Effect of starch substitution with crude glycerol on growing rabbit and lactating doe performance

The aim of this work was to study the effect of dietary inclusion of 2.5 or 5.0% of glycerol in substitution for starch on performance of lactating does and fattening rabbits. Over four consecutive reproductive cycles, a total of 81 New Zealand ´ Californian rabbit does and 813 young rabbits weaned at 25 (fattening trial 1) or 35 (fattening trial 2) days of age were allocated at random to the experimental treatments. Inclusion of glycerol in the diet up to 5% did not influence total feed consumption of does and suckling rabbits, body weight and bioelectrical impedance of does at parturition or at day 21 of lactation and litter weight at weaning, or reproductive efficiency. Substitution of starch with glycerol did not affect feed intake, weight gain or mortality during fattening. The results of the current study indicate that crude glycerol from the biofuel industry can be used at levels up to 5% in rabbit diets without any detrimental or beneficial effect on performance

Olive growing in the arid valleys of Northwest Argentina (provinces of Catamarca, La Rioja and San Juan)

En este artículo se describe la situación del olivar en las provincias argentinas de Catamarca, La Rioja y San Juan.

Problemática estructural y de funcionamiento de la cadena de valor del jamón ibérico de bellota: el caso de Guijuelo en España

El sector porcino ibérico es un sector típicamente español. La imagen que asocia el consumidor a los productos ibéricos es la correspondiente a los productos elaborados a partir de cerdos ibéricos en explotaciones extensivas, (dehesas), y cebados en montanera. Sin embargo, según los datos publicados por el Ministerio de Agricultura, Alimentación y Medio Ambiente, más de un 70 por ciento de los cerdos ibéricos que se producen en España son criados en granjas intensivas. El sector porcino ibérico está en pleno proceso de cambio, tanto por las variaciones que se derivan de la crisis que sufre el sector, como por las modificaciones que se esperan en la norma de calidad, recientemente acordadas. En este entorno en el que existe una reducción importante de los márgenes comerciales en todos los eslabones de la cadena de valor del jamón ibérico de bellota, adquiere importancia el estudio de su estructura y funcionamiento, la determinación de los aspectos que mejoran la eficiencia económica a lo largo de la misma y su concordancia a lo largo de ella. Así mismo, un sector de los consumidores comienza a buscar productos de calidad, se interesa por productos con determinados etiquetados que garantizan la calidad o unas determinadas prácticas de producción y elaboración, como sucede con los productos ecológicos. Existen numerosos estudios sobre distintos aspectos del sector porcino ibérico, realizados por distintas instituciones, como universidades, instituciones privadas y proyectos europeos. En general, se centran en la mejora de la producción de los cerdos ibéricos o en la mejora de la elaboración de los jamones. La novedad de la investigación realizada en la presente Tesis Doctoral reside en el estudio de los aspectos que determinan la mayor eficiencia económica de la cadena de valor del jamón ibérico de bellota de la denominación de origen de Guijuelo, y en las características que aporta al jamón ibérico de bellota la producción ecológica frente a la convencional. Resumen Los objetivos planteados en esta investigación son la mejora de la cadena de valor del jamón ibérico de bellota de la denominación de origen de Guijuelo, mediante el estudio de la problemática estructural y de funcionamiento de la misma. Como objetivos específicos se proponen la mejora de la eficiencia económica en las relaciones comerciales entre los distintos eslabones de la cadena de valor, y el impulso de la oferta de los productos ecológicos de ibérico, mediante el estudio comparativo de las producciones convencionales y ecológicas. Para alcanzar estos objetivos la metodología utilizada es la cadena de valor agroalimentaria, utilizando como herramientas de análisis el método Delphi y la realización de un análisis DAFO del sector porcino ibérico. Las fuentes de información primarias utilizadas proceden por una parte de la colaboración realizada en el proyecto europeo Q-Porkchains, coordinado por el Dr. Jacques H. Trienekens, y por otra parte de los cuestionarios especialmente diseñados para el análisis Delphi realizado. Las fuentes de información secundarias proceden de artículos académicos publicados, de artículos de revistas especializadas en el sector y de informes y estadísticas publicados por el Ministerio de Agricultura, Alimentación y Medio Ambiente. Las conclusiones de la investigación son las siguientes. Las relaciones comerciales de la cadena de valor estudiada están gestionadas, ya que se otorga gran valor a las relaciones comerciales basadas en la confianza, tanto en el aprovisionamiento de productos como en la venta de los mismos en cada eslabón. Sin embargo, no se gestiona adecuadamente la gama de productos que se oferta a lo largo de la cadena de valor, puesto que los eslabones de la misma obtienen diferente eficiencia económica para el mismo producto. Por otra parte, aunque la denominación de origen de Guijuelo es una marca conocida por el consumidor, el esfuerzo por tener una marca colectiva de calidad no ha sido totalmente satisfactorio, en especial para el eslabón de la distribución. Por esta razón, es importante resaltar que es recomendable la creación de una marca propia que cuide la calidad con especial atención, modificando incluso las empresas integrantes de la cadena de valor si el objetivo de calidad no coincide. Es importante garantizar la calidad del producto al consumidor, mediante la trasmisión la información generada por los informes de inspección y certificación realizados por las entidades correspondientes en relación a la norma de calidad de los productos de cerdo ibérico y por el Consejo Regulador de Guijuelo. Se requiere un estudio detallado de los posibles nichos de mercado para llegar a los clientes que buscan un producto de calidad diferenciada como es el jamón ibérico de denominación de origen de Guijuelo. Dentro de los posibles clientes debe tenerse en consideración al colectivo de personas alérgicas, ya que no se encuentran con facilidad en el mercado productos cárnicos de cerdo libres de alérgenos. Por último, la innovación es muy importante en este sector, y pueden ofertarse nuevos productos que ayuden al acortamiento de la cadena de valor, como podría ser la carne fresca de cerdo ibérico de bellota. La producción ecológica de porcino ibérico, en la actualidad no es significativa. El manejo que se realiza de los cerdos ibéricos convencionales de bellota es muy similar al manejo que se realiza de los cerdos ecológicos, salvo en la alimentación que reciben los cerdos ibéricos antes del cebo en montanera y en los medicamentos permitidos en ambas producciones. La producción de porcino ecológico de bellota puede ser interesante para la exportación. Los jamones ibéricos de bellota dispondrían de un sello que garantiza un manejo tradicional –como se realiza en muchas explotaciones extensivas de cerdos ibéricos de bellota-, y que es apreciado por los consumidores de otros países, dispuestos a pagar por productos de calidad diferenciada. Este tipo de producción quizá podría solventar la limitación al ámbito nacional de la norma de calidad de los productos de cerdo ibérico. La falta de claridad y unanimidad en el sector sobre la calidad de los productos de ibéricos que se percibe en los cambios previstos en la legislación, y el interés del eslabón de la industria elaboradora de jamones en calidades no ligadas a producciones extensivas sino intensivas, por su mayor volumen de ventas y sus mejores rendimientos, mueven a los productores de “ibérico puro de bellota” a desmarcarse del sector “ibérico”, donde el peso del producto ibérico cruzado de pienso tiene mucho peso en las decisiones que se toman. The Iberian pork industry is a typically Spanish industry. The associated image by the consumer to these products corresponds to products made from Iberian pigs in extensive farms (meadows), and fattened in open range. However, according to data released by the Ministry of Agriculture, Food and Environment, more than 70 percent of the Iberian pigs produced in Spain are raised on factory farms. The Iberian pork industry is in process of change, both by modifications resulting from the crisis in the sector, and the expected ones in the quality standard, recently agreed. In this environment where there is a significant reduction in trade margins in all links of the value chain of Iberian ham, becomes important to study its structure and operation, identifying the aspects that improve economic efficiency along the value chain and their concordance along it. Likewise, part of the consumers begins searching for quality products, they are interested in certain products that guarantee some sort of quality or production and processing practices, like organic products. There are several studies on various aspects of the Iberian pork industry, made by different institutions, such as universities, private institutions and some European projects. In general, their goal is focused on improving the Iberian hog production or on improving the elaboration of hams. The novelty of the research conducted in this PhD thesis lies in the study of the aspects that determine the economic efficiency of the value chain of Iberian ham from Guijuelo designation of origin, and the comparison between the features that organic or conventional production of Iberian ham brings to it. The objectives propound in this research are the improvement of the value chain of Iberian ham from Guijuelo designation of origin, through the study of its structural and operational problematic. The proposed specific objectives are the improvement of the economic efficiency Resumen in trade relations between the different links in the value chain, and the promotion of the supply of Iberian organic pork products, through the comparative study of conventional and organic productions. In order to achieve these objectives, the used methodology is the agrifood value chain, using as analysis tools the Delphi method, and a SWOT analysis of the Iberian pork industry. The primary sources of information come partly from the collaboration in the European project Q-Porkchains, coordinated by Dr. Jacques Trienekens, and partly from the questionnaires specially designed for the Delphi analysis performed. The secondary sources come from published academic papers, specialized journal articles and reports published by the Ministry of Agriculture, Food and Environment. The research conclusions are as follows. Trade relations in the studied value chain are managed, as it is granted a great value to business relationships based on trust, both in the supply of products and in the sale in each link. However, the portfolio that is offered throughout the value chain is not properly managed, since the economic efficiency obtained for the same product is different in each link. Moreover, although the designation of origin of Guijuelo is a well-known brand, the effort made to acquire a collective quality trademark has not been entirely satisfactory, especially in the distribution link. Due to it, it is important to highlight that it is recommended to create a brand focused on quality, and indeed to change the firms integrating the vale chain, if the goal is not shared by all the companies. It is essential to ensure the quality of the product to the consumer, through the transmission of the available information related to the quality standard of Iberian pork products and of the Guijuelo Regulating Council. A detailed study of potential niche markets is required, in order to reach customers looking for a differentiated quality product as Iberian ham of Guijuelo designation of origin. It should be taken into consideration the group of allergy sufferers as potential customers, as they do not easily find pork products in the market free of allergens. Innovation is very important in this industry, and new products could be commercialized that help to shorten the value chain, as fresh acorn Iberian pork. Nowadays, the organic production of Iberian pork products is not significant. The operation is very similar in both conventional and organic production of Iberian pork products, except in the food received by Iberian hogs and the sort of medicinal treatments allowed in each production. The organic acorn Iberian pork production could be interesting for export. Acorn Iberian hams would have a well-known hallmark, which guarantees a traditional production, -as it is done in many extensive holdings of Iberian acorn-pigs-, and that is appreciated by consumers in other countries This niche of consumers could pay for differentiated quality products. Perhaps, this sort of production could solve the limitation to national scope of the quality standard of Iberian pork products. The lack of clarity and unanimity in the industry on the quality of Iberian pork products has been perceived in the agreed changes of the legislation as well as the interest of the processing industry in hams of quality categories which are not linked to extensive but intensive productions, due to their higher sales volume and better yields. This situation pushed "acorn pure Iberian " pigs farmers to split from the Iberian industry, where the importance of cross Iberian pig from intensive farms is growing so high that they can influence the negotiations and decisions taken inside and outside the industry.

Physical characterization of growing media using standard methods (CEN)- Limitations of Applicability for pine bark and vermiculite

CEN standards have helped to harmonize analytical methods for substrate analysis.Though, for special substrates or constituents the applicability might be Iimited. In this paper a comparative study of implementation of CEN standards to samples of pine bark and vermiculite has been carried out. For composted pine bark, an elongation of the equilibrium period up to 72 instead of 48 hours might increase the accuracy of determinations physical parameters according to EN 13041. For vermiculite, we suggest pycnometry as a feasible technique for the determination of particle density (PD), as the determination of organic matter (OM) as requested by EN 13041 for the calculation of the PD seems not to be applicable for this kind of material.

Bile Acids Induce Glucagon-Like Peptide 2 Secretion with Limited Effects on Intestinal Adaptation in Early Weaned Pigs

Early weaning is a stressful event characterized by a transient period of intestinal atrophy that may be mediated by reduced secretion of glucagon-like peptide (GLP) 2. We tested whether enterally fed bile acids or plant sterols could increase nutrient-dependent GLP-2 secretion and improve intestinal adaptation in weanling pigs. During the first 6 d after weaning, piglets were intragastrically infused once daily with either deionized water -control-, chenodeoxycholic acid -CDC; 60mg/kg body weight-, or b-sitoesterol -BSE; 100 mg/kg body weight-. Infusing CDC increased plasma GLP-2 -P menor que 0.05- but did not affect plasma GLP-1 and feed intake. The intestinal expression of Glp2r -glucagon-like peptide 2 receptor-, Asbt -sodium-dependent bile acid transporter-, Fxr -farnesoid X receptor-, and Tgr5 -guanosine protein?coupled bile acid receptor- genes were not affected by CDC treatment. The intragastric administration of CDC did not alter the weight and length of the intestine, yet increased the activation of caspase-3 in ileal villi -P menor que 0.02- and the expression of Il6 -interleukin 6; P menor que 0.002- in the jejunum. In contrast, infusing BSE did not affect any of the variables that were measured. Our results show that the enteral administration of the bile acid CDC potentiates the nutrient-induced secretion of endogenous GLP-2 in early-weaned pigs. Bile acid?enhanced release of GLP-2, however, did not result in improved intestinal growth, morphology, or inflammation during the postweaning degenerative phase.

Influence of crude protein content, ingredient complexity, feed form, and duration of feeding of the phase I diets on productive performance and nutrient digestibility of Iberian pigs.

The influence of CP content and ingredient complexity, feed form, and duration of feeding of the Phase I diets on growth performance and total tract apparent digestibility -TTAD- of energy and nutrients was studied in Iberian pigs weaned at 28 d of age. There were 12 dietary treatments with 2 type of feeds -high-quality, HQ; and low-quality, LQ-, 2 feed forms -pellets vs. mash-, and 3 durations -7, 14, and 21 d- of supply of the Phase I diets.

Improving parameters selection of a seeded region growing method for multiband image segmentation

In the last decade, Object Based Image Analysis (OBIA) has been accepted as an effective method for processing high spatial resolution multiband images. This image analysis method is an approach that starts with the segmentation of the image. Image segmentation in general is a procedure to partition an image into homogenous groups (segments). In practice, visual interpretation is often used to assess the quality of segmentation and the analysis relies on the experience of an analyst. In an effort to address the issue, in this study, we evaluate several seed selection strategies for an automatic image segmentation methodology based on a seeded region growing-merging approach. In order to evaluate the segmentation quality, segments were subjected to spatial autocorrelation analysis using Moran's I index and intra-segment variance analysis. We apply the algorithm to image segmentation using an aerial multiband image.

Management factors affecting mortality, feed intake, and feed conversion ratio of grow-finishing pigs

The aim of this study was to determine the effect of animal management and farm facilities on total feed intake (TFI), feed conversion ratio (FCR) and mortality rate (MORT) of grower-finishing pigs. In total, 310 batches from 244 grower-finishing farms, consisting of 454 855 Pietrain sired pigs in six Spanish pig companies were used. Data collection consisted of a survey on management practices (season of placement, split-sex by pens, number of pig origins, water source in the farm, initial or final BW) and facilities (floor, feeder, ventilation or number of animals placed) during 2008 and 2009. Results indicated that batches of pigs placed between January and March had higher TFI (P=0.006), FCR (P=0.005) and MORT (P=0.03) than those placed between July and September. Moreover, batches of pigs placed between April and June had lower MORT (P=0.003) than those placed between January and March. Batches which had split-sex pens had lower TFI (P=0.001) and better FCR (P<0.001) than those with mixed-sex in pens; pigs fed with a single-space feeder with incorporated drinker also had the lowest TFI (P<0.001) and best FCR (P<0.001) in comparison to single and multi-space feeders without a drinker. Pigs placed in pens with <50% slatted floors presented an improvement in FCR (P<0.05) than pens with 50% or more slatted floors. Batches filled with pigs from multiple origins had higher MORT (P<0.001) than those from a single origin. Pigs housed in barns that performed manual ventilation control presented higher MORT (P<0.001) in comparison to automatic ventilation. The regression analysis also indicated that pigs which entered to grower-finisher facilities with higher initial BW had lower MORT (P<0.05) and finally pigs which were sent to slaughterhouse with a higher final BW presented higher TFI (P<0.001). The variables selected for each dependent variable explained 61.9%, 24.8% and 20.4% of the total variability for TFI, FCR and MORT, respectively. This study indicates that farms can increase growth performance and reduce mortality by improving farm facilities and/or modifying management practices.

Quantitative analysis of morphological changes in yeast colonies growing on solid medium: the eccentricity and Fourier indices

The colony shape of four yeast species growing on agar medium wasmeasured for 116 days by image analysis. Initially, all the colonies are circular, with regular edges. The loss of circularity can be quantitatively estimated by the eccentricity index, Ei, calculated as the ratio between their orthogonal vertical and horizontal diameters. Ei can increase from 1 (complete circularity) to a maximum of 1.17–1.30, depending on the species. One colony inhibits its neighbour only when it has reached a threshold area. Then, Ei of the inhibited colony increases proportionally to the area of the inhibitory colony. The initial distance between colonies affects those threshold values but not the proportionality, Ei/area; this inhibition affects the shape but not the total surface of the colony. The appearance of irregularities in the edges is associated, in all the species, not with age but with nutrient exhaustion. The edge irregularity can be quantified by the Fourier index, Fi, calculated by the minimum number of Fourier coefficients that are needed to describe the colony contour with 99% fitness. An ad hoc function has been developed in Matlab v. 7.0 to automate the computation of the Fourier coefficients. In young colonies, Fi has a value between 2 (circumference) and 3 (ellipse). These values are maintained in mature colonies of Debaryomyces, but can reach values up to 14 in Saccharomyces.All the species studied showed the inhibition of growth in facing colony edges, but only three species showed edge irregularities associated with substrate exhaustion. Copyright © 2014 John Wiley & Sons, Ltd.

Ammonia and methane gas emissions from pig slurry: variability induced through feeding strategies

Esta Tesis doctoral fue desarrollada para estudiar las emisiones de amoniaco (NH3) y metano (CH4) en purines de cerdos, y los efectos ocasionados por cambios en la formulación de la dieta. Con este propósito, fueron llevados a cabo tres estudios. El experimento 1 fue realizado con el objetivo de analizar los factores de variación de la composición de purines y establecer ecuaciones de predicción para emisiones potenciales de NH3 y CH4. Fueron recogidas setenta y nueve muestras de piensos y purines durante dos estaciones del año (verano y invierno) de granjas comerciales situadas en dos regiones de España (Centro y Mediterráneo). Se muestrearon granjas de gestación, maternidad, lactación y cebo. Se determinó la composición de piensos y purines, y la emisión potencial de NH3 y CH4. El contenido de nutrientes de los piensos fue usado como covariable en el análisis. La espectroscopia de reflectancia del infrarrojo cercano (NIRS) se evaluó como herramienta de predicción de la composición y potencial emisión de gases del purín. Se encontró una amplia variabilidad en la composición de piensos y purines. Las granjas del Mediterráneo tenían mayor pH (P<0,001) y concentración de cenizas (P =0,02) en el purín que las del Centro. El tipo de granja también afectó al contenido de extracto etéreo (EE) del purín (P =0,02), observando los valores más elevados en las instalaciones de animales jóvenes. Los resultados sugieren un efecto tampón de la fibra de la dieta en el pH del purín y una relación directa (P<0,05) con el contenido de fibra fecal. El contenido de proteína del pienso no afectó al contenido de nitrógeno del purín, pero disminuyó (P=0,003) la concentración de sólidos totales (ST) y de sólidos volátiles (SV). Se obtuvieron modelos de predicción de la emisión potencial de NH3 (R2=0,89) y CH4 (R2=0,61) partir de la composición del purín. Los espectros NIRS mostraron una buena precisión para la estimación de la mayor parte de los constituyentes, con coeficientes de determinación de validación cruzada (R2cv) superiores a 0,90, así como para la predicción del potencial de emisiones de NH3 y CH4 (R2cv=0,84 y 0,68, respectivamente). El experimento 2 fue realizado para investigar los efectos del nivel de inclusión de dos fuentes de sub-productos fibrosos: pulpa de naranja (PN) y pulpa de algarroba (PA), en dietas iso-fibrosas de cerdos de cebo, sobre la composición del purín y las emisiones potenciales de NH3 y CH4. Treinta cerdos (85,4±12,3 kg) fueron alimentados con cinco dietas iso-nutritivas: control comercial trigo/cebada (C) y cuatro dietas experimentales incluyendo las dos fuentes de sub-productos a dos niveles (75 y 150 g/kg) en una estructura 2 × 2 factorial. Después de 14 días de periodo de adaptación, heces y orina fueron recogidas separadamente durante 7 días para medir la digestibilidad de los nutrientes y el nitrógeno (N) excretado (6 réplicas por dieta) en cerdos alojados individualmente en jaulas metabólicas. Las emisiones de NH3 y CH4 fueron medidas después de la recogida de los purínes durante 11 y 100 días respectivamente. La fuente y el nivel de subproductos fibrosos afectó a la eficiencia digestiva de diferentes formas, ya que los coeficientes de digestibilidad total aparente (CDTA) para la materia seca (MS), materia orgánica (MO), fracciones fibrosas y energía bruta (EB) aumentaron con la PN pero disminuyeron con la inclusión de PA (P<0,05). El CDTA de proteína bruta (PB) disminuyó con la inclusión de las dos fuentes de fibra, siendo más bajo al mayor nivel de inclusión. La concentración fecal de fracciones fibrosas aumentó (P<0,05) con el nivel de inclusión de PA pero disminuyó con el de PN (P<0,01). El nivel más alto de las dos fuentes de fibra en el pienso aumentó (P<0,02) el contenido de PB fecal pero disminuyó el contenido de N de la orina (de 205 para 168 g/kg MS, P<0,05) en todas las dietas suplementadas comparadas con la dieta C. Adicionalmente, las proporciones de nitrógeno indigerido, nitrógeno soluble en agua, nitrógeno bacteriano y endógeno excretado en heces no fueron afectados por los tratamientos. Las características iniciales del purín no difirieron entre las diferentes fuentes y niveles de fibra, excepto para el pH que disminuyó con la inclusión de altos niveles de sub-productos. La emisión de NH3 por kg de purín fue más baja en todas las dietas suplementadas con fibras que en la dieta C (2,44 vs.1,81g de promedio, P<0,05). Además, purines de dietas suplementadas con alto nivel de sub-productos tendieron (P<0,06) a emitir menos NH3 por kg de nitrógeno total y mostraron un potencial más bajo para emitir CH4, independientemente de la fuente de fibra. El experimento 3 investigó los efectos de la fuente de proteína en dietas prácticas. Tres piensos experimentales fueron diseñados para sustituir una mescla de harina y cascarilla de soja (SOJ) por harina de girasol (GIR) o por DDGS del trigo (DDGST). La proporción de otros ingredientes fue modificada para mantener los contenidos de nutrientes similares a través de las dietas. El cambio en la fuente de proteína dio lugar a diferencias en el contenido de fibra neutro detergente ligada a proteína bruta (FNDPB), fibra soluble (FS) y lignina ácido detergente (LAD) en la dieta. Veinticuatro cerdos (ocho por dieta), con 52,3 o 60,8 kg en la primera y segunda tanda respectivamente, fueron alojados individualmente en jaulas metabólicas. Durante un periodo de 7 días fue determinado el balance de MS, el CDTA de los nutrientes y la composición de heces y orina. Se realizó el mismo procedimiento del experimento 2 para medir las emisiones de NH3 y CH4 de los purines de cada animal. Ni la ingestión de MS ni el CDTA de la MS o de la energía fueron diferentes entre las dietas experimentales, pero el tipo de pienso afectó (P<0.001) la digestibilidad de la PB, que fue mayor para GIR (0,846) que para SOJ (0,775), mientras que la dieta DDGST mostró un valor intermedio (0,794). La concentración fecal de PB fue por tanto influenciada (P<0,001) por el tratamiento, observándose la menor concentración de PB en la dieta GIR y la mayor en la dieta SOJ. La proporción de N excretado en orina o heces disminuyó de 1,63 en la dieta GIR hasta 0,650 en la dieta SOJ, como consecuencia de perdidas más bajas en orina y más altas en heces, con todas las fracciones de nitrógeno fecales creciendo en paralelo a la excreción total. Este resultado fue paralelo a una disminución de la emisión potencial de NH3 (g/kg purín) en la dieta SOJ con respecto a la dieta GIR (desde 1,82 a 1,12, P<0,05), dando valores intermedios (1,58) para los purines de la dieta DDGST. Por otro lado, el CDTA de la FS y de la fibra neutro detergente (FND) fueron afectados (P<0,001 y 0,002, respectivamente) por el tipo de dieta, siendo más bajas en la dieta GIR que en la dieta SOJ; además, se observó un contenido más alto de FND (491 vs. 361g/kg) en la MS fecal para la dieta GIR que en la dieta SOJ, presentando la dieta DDGST valores intermedios. El grado de lignificación de la FND (FAD/FND x 100) de las heces disminuyó en el orden GIR>DDGST>SOJ (desde 0,171 hasta 0,109 y 0,086, respectivamente) en paralelo a la disminución del potencial de emisión de CH4 por g de SV del purín (desde 301 a 269 y 256 mL, respectivamente). Todos los purines obtenidos en estos tres experimentos y Antezana et al. (2015) fueron usados para desarrollar nuevas calibraciones con la tecnología NIRS, para predecir la composición del purín y el potencial de las emisiones de gases. Se observó una buena precisión (R2cv superior a 0,92) de las calibraciones cuando muestras de los ensayos controlados (2, 3 y Antezana et al., 2015) fueron añadidas, aumentando el rango de variación. Una menor exactitud fue observada para TAN y emisiones de NH3 y CH4, lo que podría explicarse por una menor homogeneidad en la distribución de las muestras cuando se amplía el rango de variación del estudio. ABSTRACT This PhD thesis was developed to study the emissions of ammonia (NH3) and methane (CH4) from pig slurry and the effects caused by changes on diet formulation. For these proposes three studies were conducted. Experiment 1 aimed to analyse several factors of variation of slurry composition and to establish prediction equations for potential CH4 and NH3 emissions. Seventy-nine feed and slurry samples were collected at two seasons (summer and winter) from commercial pig farms sited at two Spanish regions (Centre and Mediterranean). Nursery, growing-fattening, gestating and lactating facilities were sampled. Feed and slurry composition were determined, and potential CH4 and NH3 emissions measured. Feed nutrient contents were used as covariates in the analysis. Near infrared reflectance spectroscopy (NIRS) was evaluated as a predicting tool for slurry composition and potential gaseous emissions. A wide variability was found both in feed and slurry composition. Mediterranean farms had a higher pH (P<0.001) and ash (P=0.02) concentration than those located at the centre of Spain. Also, type of farm affected ether extract (EE) content of the slurry (P=0.02), with highest values obtained for the youngest animal facilities. Results suggested a buffer effect of dietary fibre on slurry pH and a direct relationship (P<0.05) with fibre constituents of manure. Dietary protein content did not affect slurry nitrogen content (N) but decreased (P=0.003) in total solid (TS) and volatile solids (VS) concentration. Prediction models of potential NH3 emissions (R2=0.89) and biochemical CH4 potential (B0) (R2=0.61) were obtained from slurry composition. Predictions from NIRS showed a high accuracy for most slurry constituents with coefficient of determination of cross validation (R2cv) above 0.90 and a similar accuracy of prediction of potential NH3 and CH4 emissions (R2cv=0.84 and 0.68, respectively) thus models based on slurry composition from commercial farms. Experiment 2 was conducted to investigate the effects of increasing the level of two sources of fibrous by-products, orange pulp (OP) and carob meal (CM), in iso-fibrous diets for growing-finishing pig, slurry composition and potential NH3 and CH4 emissions. Thirty pigs (85.4±12.3 kg) were fed five iso-nutritive diets: a commercial control wheat/barley (C) and four experimental diets including two sources of fibrous by-products OP and CM and two dietary levels (75 and 150 g/kg) in a 2 × 2 factorial arrangement. After a 14-day adaptation period, faeces and urine were collected separately for 7 days to measure nutrient digestibility and the excretory patterns of N from pigs (6 replicates per diet) housed individually in metabolic pens. For each animal, the derived NH3 and CH4 emissions were measured in samples of slurry over an 11 and 100-day storage periods, respectively. Source and level of the fibrous by-products affected digestion efficiency in a different way as the coefficients of total tract apparent digestibility (CTTAD) for dry matter (DM), organic matter (OM), fibre fractions and gross energy (GE) increased with OP but decreased with CM (P<0.05). Crude protein CTTAD decreased with the inclusion of both sources of fibre, being lower at the highest dietary level. Faecal concentration of fibre fractions increased (P<0.05) with the level of inclusion of CM but decreased with that of OP (P<0.01). High dietary level for both sources of fibre increased (P<0.02) CP faecal content but urine N content decreased (from 205 to 168 g/kg DM, P<0.05) in all the fibre-supplemented compared to C diet. Additionally, the proportions of undigested dietary, water soluble, and bacterial and endogenous debris of faecal N excretion were not affected by treatments. The initial slurry characteristics did not differ among different fibre sources and dietary levels, except pH, which decreased at the highest by-product inclusion levels. Ammonia emission per kg of slurry was lower in all the fibre-supplemented diets than in C diet (2.44 vs. 1.81g as average, P<0.05). Additionally, slurries from the highest dietary level of by-products tended (P<0.06) to emit less NH3 per kg of initial total Kjeldahl nitrogen (TKN) and showed a lower biochemical CH4 potential , independently of the fibre source. Experiment 3 investigated the effects of protein source in practical diets. Three experimental feeds were designed to substitute a mixture of soybean meal and soybean hulls (SB diet) with sunflower meal (SFM) or wheat DDGS (WDDGS). The proportion of other ingredients was also modified in order to maintain similar nutrient contents across diets. Changes in protein source led to differences in dietary content of neutral detergent insoluble crude protein (NDICP), soluble fibre (SF) and acid detergent lignin (ADL). Twenty-four pigs (eight per diet), weighing 52.3 or 60.8 kg at the first and second batch respectively, were housed individually in metabolic pens to determine during a 7-day period DM balance, CTTAD of nutrients, and faecal and urine composition. Representative slurry samples from each animal were used to measure NH3 and CH4 emissions over an 11 and or 100-day storage period, respectively. Neither DM intake, nor DM or energy CTTAD differed among experimental diets, but type of feed affected (P<0.001) CP digestibility, which was highest for SFM (0.846) than for SB (0.775) diet, with WDDGS-based diet giving an intermediate value (0.794). Faecal DM composition was influenced (P<0.001) accordingly, with the lowest CP concentration found for diet SFM and the highest for SB. The ratio of N excreted in urine or faeces decreased from SFM (1.63) to SB diet (0.650), as a consequence of both lower urine and higher faecal losses, with all the faecal N fractions increasing in parallel to total excretion. This result was parallel to a decrease of potential NH3 emission (g/kg slurry) in diet SB with respect to diet SFM (from 1.82 to 1.12, P<0.05), giving slurry from WDDGS-based diet an intermediate value (1.58). Otherwise, SF and insoluble neutral detergent fibre (NDF) CTTAD were affected (P<0.001 and P=0.002, respectively) by type of diet, being lower for SFM than in SB-diet; besides, a higher content of NDF (491 vs. 361 g/kg) in faecal DM was observed for SFM with respect to SB based diet, with WDDGS diet being intermediate. Degree of lignification of NDF (ADL/NDF x 100) of faeces decreased in the order SFM>WDDGS>SB (from 0.171 to 0.109 and 0.086, respectively) in parallel to a decrease of biochemical CH4 potential per g of VS of slurry (from 301 to 269 and 256 ml, respectively). All slurry samples obtained from these three experiments and Antezana et al. (2015) were used to develop new calibrations with NIRS technology, to predict the slurry composition and potential gaseous emissions of samples with greater variability in comparison to experiment 1. Better accuracy (R2cv above 0.92) was observed for calibrations when samples from controlled trials experiments (2, 3 and Antezana et al., 2015) were included, increasing the range of variation. A lower accuracy was observed for TAN, NH3 and CH4 gaseous emissions, which might be explained by the less homogeneous distribution with a wider range of data.

Influence of castration on growth performance and carcass and meat quality of heavy female pigs

The main objetive of this Doctoral Thesis was to study the influence of female castration and pig sex on growth performance and carcass and meat quality of white pigs slaughtered at different final weights. Three experiments (Exp.) were conducted. In Exp. 1, a total of 200 (Landrace * Large White dam x Pietrain * Large White sire) gilts of 50 ± 3 days of age (23.3 ± 1.47 kg BW) was used to investigate the effects of castration (intact females, IF vs. castrated feamles, CF) and slaughter weight (106 vs. 122 kg BW) on productive performance and carcass and meat quality. There were four experimental treatments arranged as a 2 x 2 factorial and 5 replicates of 10 pigs each per treatment. Half of the gilts were ovariectomized at 58 d of age (8 days after the beginning of the trial; 29.8 ± 1.64 kg BW) whereas the other half remained intact. Meat samples were taken at m. Longissimus thoracis at the level of the last rib and subcutaneous fat samples were taken at the tail insertion. For the entire experiment period, CF had higher BW gain (P<0.05) and backfat and m. Gluteus medius (GM) fat thickness (P<0.001) than IF. However, IF had higher loin and trimmed primal cut yields (P<0.05) than CF. Meat quality was similar for IF and CF but the proportion of linoleic acid in subcutaneous fat was higher (P<0.001) for IF. Pigs slaughtered at 122 kg BW had higher (P<0.001) feed intake and poorer feed efficiency than pigs slaughtered at 106 kg BW. An increase in slaughter weight (SW) improved (P<0.001) carcass yield but decreased (P<0.05) trimmed primal cut yield. Meat from females slaughtered at the heavier BW was redder (a*; P<0.001) and had more (P<0.01) intramuscular fat and less thawing (P<0.05) and cooking (P<0.10) loss than meat from females slaughtered at the lighter BW. Also, females slaughtered at 122 kg BW had less (P<0.01) linoleic acid content in the subcutaneous fat than pigs slaughtered at 106 kg BW. Castration of gilts and slaughtering at heavier BW might be useful practices for the production of heavy pigs destined to the dry cured industry in which a certain amount of fat in the carcass is required. In contrast, when the carcasses are destined to fresh meat production, IF slaughtered at 106 kg BW are a more efficient alternative. In Exp. 2, crossbred pigs (n=240) from Pietrain*Large White sires mated to Landrace*Large White dams with an average of 100 d of age (60.5 ± 2.3 kg) were used to investigate the effects of gender and slaughter weight (SW) on growth performance and carcass and meat quality characteristics. There were 6 treatments arranged factorially with 3 genders (IF vs. CF vs.castrated males, CM) and 2 SW (114 vs. 122 kg BW). Each of the 6 combinations of treatments was replicated 4 times and the experimental unit was a pen with 10 pigs. Castrated males and CF ate more feed, grew faster and had more carcass backfat depth and fat thickness at the GM muscle, but lower loin yield than IF (P<0.05). In addition, CF and CM had more intramuscular fat (P<0.05) and less linoleic acid content in the subcutaneous fat (P<0.01) than IF. Pigs slaughtered at 122 kg BW had lower ADG (P<0.05), poor gain-to-feed ratio (P<0.05), and more GM fat than pigs slaughtered at 114 kg BW (P < 0.05). It is concluded that CF and CM had similar productive performance and meat quality characteristics when slaughtered at the same age, and that the castration of females improved daily gains and increased weight and fat content of primal cuts with respect to IF. Therefore, castration of females is recommended in pigs destined to the dry-cured industry because of the beneficial effects on the quality of the primal cuts. In Exp. 3, the effects of gender and castration of females (IF vs. CF vs. CM) on performance and carcass and meat quality were studied in crossbred pigs (Landrace x Large White dams x Duroc sires) slaughtered at 119.2 (trial 1) or 131.6 (trial 2) kg BW. Intact females had better feed conversion and less carcass fat than CF and CM. Trimmed shoulder yield was higher for CM than for CF with IF being intermediate. Primal cut yield and meat quality, however were similar for all treatments. Proportion of linoleic acid in backfat was lower for CF than for IF or CM, and the differences were significant in pigs slaughtered witn 131.6 kg BW. The higher fat content and the fatty acid profile favour the use of CF and CM over IF for the production of heavy pigs destined to the dry-cured industry.

Validation and aplication of Bioelectrical Impedance (BIA) method to determine body and carcass composition and nutrient retention of growing rabbits = Validación y aplicación de la técnica de la Impedancia Bioeléctrica (BIA) para determinar la composición corporal, de la canal y la retención de nutrientes de conejos en crecimiento

Los objetivos de esta tesis fueron 1) obtener y validar ecuaciones de predicción para determinar in vivo la composición corporal y de la canal de conejos en crecimiento de 25 a 77 días de vida utilizando la técnica de la Impedancia Bioeléctrica (BIA), y 2) evaluar su aplicación para determinar diferencias en la composición corporal y de la canal, así como la retención de nutrientes de animales alimentados con diferentes fuentes y niveles de grasa. El primer estudio se realizó para determinar y después validar, usando datos independientes, las ecuaciones de predicción obtenidas para determinar in vivo la composición corporal de los conejos en crecimiento. Se utilizaron 150 conejos a 5 edades distintas (25, 35, 49, 63 y 77 días de vida), con un rango de pesos entre 231 y 3138 g. Para determinar los valores de resistencia (Rs,) and reactancia (Xc,) se usó un terminal (Model BIA-101, RJL Systems, Detroit, MI USA) con cuatro electrodos. Igualmente se registró la distancia entre electrodos internos (D), la longitud corporal (L) y el peso vivo (PV) de cada animal. En cada edad, los animales fueron molidos y congelados (-20 ºC) para su posterior análisis químico (MS, grasa, proteína, cenizas y EB). El contenido en grasa y energía de los animales se incrementó, mientras que los contenidos en proteína, cenizas y agua de los animales disminuyeron con la edad. Los valores medios de Rs, Xc, impedancia (Z), L y D fueron 83.5 ± 23.1 , 18.2 ± 3.8 , 85.6 ± 22.9 , 30.6 ± 6.9 cm y 10.8 ± 3.1 cm. Se realizó un análisis de regresión lineal múltiple para determinar las ecuaciones de predicción, utilizando los valores de PV, L and Z como variables independientes. Las ecuaciones obtenidas para estimar los contenidos en agua (g), PB (g), grasa (g), cenizas (g) and EB (MJ) tuvieron un coeficiente de determinación de (R2) de 0.99, 0.99, 0.97, 0.98 y 0.99, y los errores medios de predicción relativos (EMPR) fueron: 2.79, 6.15, 24.3, 15.2 y 10.6%, respectivamente. Cuando el contenido en agua se expresó como porcentaje, los valores de R2 y EMPR fueron 0.85 and 2.30%, respectivamente. Al predecir los contenidos en proteína (%MS), grasa (%MS), cenizas (%MS) y energía (kJ/100 g MS), se obtuvieron valores de 0.79, 0.83, 0.71 y 0.86 para R2, y 5.04, 18.9, 12.0 y 3.19% para EMPR. La reactancia estuvo negativamente correlacionada con el contenido en agua, cenizas y PB (r = -0.32, P < 0.0001; r = -0.20, P < 0.05; r = -0.26, P < 0.01) y positivamente correlacionada con la grasa y la energía (r = 0.23 y r = 0.24; P < 0.01). Sin embargo, Rs estuvo positivamente correlacionada con el agua, las cenizas y la PB (r = 0.31, P < 0.001; r = 0.28, P < 0.001; r = 0.37, P < 0.0001) y negativamente con la grasa y la energía (r = -0.36 y r = -0.35; P < 0.0001). Igualmente la edad estuvo negativamente correlacionada con el contenido en agua, cenizas y proteína (r = -0.79; r = -0.68 y r = -0.80; P < 0.0001) y positivamente con la grasa y la energía (r = 0.78 y r = 0.81; P < 0.0001). Se puede concluir que el método BIA es una técnica buena y no invasiva para estimar in vivo la composición corporal de conejos en crecimiento de 25 a 77 días de vida. El objetivo del segundo estudio fue determinar y validar con datos independientes las ecuaciones de predicción obtenidas para estimar in vivo la composición de la canal eviscerada mediante el uso de BIA en un grupo de conejos de 25 a 77 días, así como testar su aplicación para predecir la retención de nutrientes y calcular las eficacias de retención de la energía y del nitrógeno. Se utilizaron 75 conejos agrupados en 5 edades (25, 35, 49, 63 y 77 días de vida) con unos pesos que variaron entre 196 y 3260 g. Para determinar los valores de resistencia (Rs, ) y reactancia (Xc, ) se usó un terminal (Model BIA-101, RJL Systems, Detroit, MI USA) con cuatro electrodos. Igualmente se registró la distancia entre electrodos internos (D), la longitud corporal (L) y el peso vivo (PV) del cada animal. En cada edad, los animales fueron aturdidos y desangrados. Su piel, vísceras y contenido digestivo fueron retirados, y la canal oreada fue pesada y molida para posteriores análisis (MS, grasa, PB, cenizas y EB). Los contenidos en energía y grasa aumentaron mientras que los de agua, cenizas y proteína disminuyeron con la edad. Los valores medios de Rs, Xc, impedancia (Z), L y D fueron 95.9±23.9 , 19.5±4.7 , 98.0±23.8 , 20.6±6.3 cm y 13.7±3.1 cm. Se realizó un análisis de regresión linear múltiple para determinar las ecuaciones de predicción, utilizando los valores de PV, L and Z como variables independientes. Los coeficientes de determinación (R2) de las ecuaciones obtenidas para estimar los contenidos en agua (g), PB (g), grasa (g), cenizas (g) and EB (MJ) fueron: 0.99, 0.99, 0.95, 0.96 y 0.98, mientras que los errores medios de predicción relativos (EMPR) fueron: 4.20, 5.48, 21.9, 9.10 y 6.77%, respectivamente. Cuando el contenido en agua se expresó como porcentaje, los valores de R2 y EMPR fueron 0.79 y 1.62%, respectivamente. Cuando se realizó la predicción de los contenidos en proteína (%MS), grasa (%MS), cenizas (%MS) y energía (kJ/100 g MS), los valores de R2 fueron 0.68, 0.76, 0.66 and 0.82, y los de RMPE: 3.22, 10.5, 5.82 and 2.54%, respectivamente. La reactancia estuvo directamente correlacionada con el contenido en grasa (r = 0.24, P < 0.05), mientras que la resistencia guardó una correlación positiva con los contenidos en agua, cenizas y proteína (r = 0.55, P < 0.001; r = 0.54, P < 0.001; r = 0.40, P < 0.005) y negativa con la grasa y la energía (r = -0.44 y r = -0.55; P < 0.001). Igualmente la edad estuvo negativamente correlacionada con los contenidos en agua, cenizas y PB (r = -0.94; r = -0.85 y r = -0.75; P < 0.0001) y positivamente con la grasa y la energía (r = 0.89 y r = 0.90; P < 0.0001). Se estudió la eficacia global de retención de la energía (ERE) y del nitrógeno (ERN) durante todo el periodo de cebo (35-63 d), Los valores de ERE fueron 20.4±7.29%, 21.0±4.18% and 20.8±2.79% en los periodos 35 a 49, 49 a 63 y 35 a 63 d, respectivamente. ERN fue 46.9±11.7%, 34.5±7.32% y 39.1±3.23% para los mismos periodos. La energía fue retenida en los tejidos para crecimiento con una eficiencia del 52.5% y la eficiencia de retención de la energía como proteína y grasa fue de 33.3 y 69.9% respectivamente. La eficiencia de utilización del nitrógeno para crecimiento fue cercana al 77%. Este trabajo muestra como el método BIA es técnica buena y no invasiva para determinar in vivo la composición de la canal y la retención de nutrientes en conejos en crecimiento de 25 a 77 días de vida. En el tercer estudio, se llevaron a cabo dos experimentos con el fin de investigar los efectos del nivel de inclusión y de la fuente de grasa, sobre los rendimientos productivos, la mortalidad, la retención de nutrientes y la composición corporal total y de la canal eviscerada de conejos en crecimiento de 34 a 63 d de vida. En el Exp. 1 se formularon 3 dietas con un diseño experimental factorial 3 x 2 con el tipo de grasa utilizada: Aceite de Soja (SBO), Lecitinas de Soja (SLO) y Manteca (L) y el nivel de inclusión (1.5 y 4%) como factores principales. El Exp. 2 también fue diseñado con una estructura factorial 3 x 2, pero usando SBO, Aceite de Pescado (FO) y Aceite de Palmiste como fuentes de grasa, incluidas a los mismos niveles que en el Exp. 1. En ambos experimentos 180 animales fueron alojados en jaulas individuales (n=30) y 600 en jaulas colectivas en grupos de 5 animales (n=20). Los animales alimentados con un 4% de grasa añadida tuvieron unos consumos diarios y unos índices de conversión más bajos que aquellos alimentados con las dietas con un 1.5% de grasa. En los animales alojados en colectivo del Exp. 1, el consumo fue un 4.8% más alto en los que consumieron las dietas que contenían manteca que en los animales alimentados con las dietas SBO (P = 0.036). La inclusión de manteca tendió a reducir la mortalidad (P = 0.067) en torno al 60% y al 25% con respecto a las dietas con SBO y SLO, respectivamente. La mortalidad aumentó con el nivel máximo de inclusión de SLO (14% vs. 1%, P < 0.01), sin observarse un efecto negativo sobre la mortalidad con el nivel más alto de inclusión de las demás fuentes de grasa utilizadas. En los animales alojados colectivo del Exp. 2 se encontró una disminución del consumo (11%), peso vivo a 63 d (4.8%) y de la ganancia diaria de peso (7.8%) con la inclusión de aceite de pescado con respecto a otras dietas (P < 0.01). Los dos últimos parámetros se vieron especialmente más reducidos cuando en las dietas se incluyó el nivel más alto de FO (5.6 y 9.5%, respectivamente, (P < 0.01)). Los animales alojados individualmente mostraron unos resultados productivos muy similares. La inclusión de aceite pescado tendió (P = 0.078) a aumentar la mortalidad (13.2%) con respecto al aceite de palmiste (6.45%), siendo intermedia para las dietas que contenían SBO (8.10%). La fuente o el nivel de grasa no afectaron la composición corporal total o de la canal eviscerada de los animales. Un incremento en el nivel de grasa dio lugar a una disminución de la ingesta de nitrógeno digestible (DNi) (1.83 vs. 1.92 g/d; P = 0.068 en Exp. 1 y 1.79 vs. 1.95 g/d; P = 0.014 en Exp. 2). Debido a que el nitrógeno retenido (NR) en la canal fue similar para ambos niveles (0.68 g/d (Exp. 1) y 0.71 g/d (Exp. 2)), la eficacia total de retención del nitrógeno (ERN) aumentó con el nivel máximo de inclusión de grasa, pero de forma significativa únicamente en el Exp. 1 (34.9 vs. 37.8%; P < 0.0001), mientras que en el Exp. 2 se encontró una tendencia (36.2 vs. 38.0% en Exp. 2; P < 0.064). Como consecuencia, la excreción de nitrógeno en heces fue menor en los animales alimentados con el nivel más alto de grasa (0.782 vs. 0.868 g/d; P = 0.0001 en Exp. 1, y 0.745 vs. 0.865 g/d; P < 0.0001 en Exp.2) al igual que el nitrógeno excretado en orina (0.702 vs. 0.822 g/d; P < 0.0001 en Exp. 1 y 0.694 vs. 0.7999 g/d; P = 0.014 en Exp.2). Aunque no hubo diferencias en la eficacia total de retención de la energía (ERE), la energía excretada en heces disminuyó al aumentar el nivel de inclusión de grasa (142 vs. 156 Kcal/d; P = 0.0004 en Exp. 1 y 144 vs. 154 g/d; P = 0.050 en Exp. 2). Sin embargo, la energía excretada como orina y en forma de calor fue mayor en el los animales del Exp. 1 alimentados con el nivel más alto de grasa (216 vs. 204 Kcal/d; P < 0.017). Se puede concluir que la manteca y el aceite de palmiste pueden ser considerados como fuentes alternativas al aceite de soja debido a la reducción de la mortalidad, sin efectos negativos sobre los rendimientos productivos o la retención de nutrientes. La inclusión de aceite de pescado empeoró los rendimientos productivos y la mortalidad durante el periodo de crecimiento. Un aumento en el nivel de grasa mejoró el índice de conversión y la eficacia total de retención de nitrógeno. ABSTRACT The aim of this Thesis is: 1) to obtain and validate prediction equations to determine in vivo whole body and carcass composition using the Bioelectrical Impedance (BIA) method in growing rabbits from 25 to 77 days of age, and 2) to study its application to determine differences on whole body and carcass chemical composition, and nutrient retention of animals fed different fat levels and sources. The first study was conducted to determine and later validate, by using independent data, the prediction equations obtained to assess in vivo the whole body composition of growing rabbits. One hundred and fifty rabbits grouped at 5 different ages (25, 35, 49, 63 and 77 days) and weighing from 231 to 3138 g were used. A four terminal body composition analyser was used to obtain resistance (Rs, ) and reactance (Xc, ) values (Model BIA-101, RJL Systems, Detroit, MI USA). The distance between internal electrodes (D, cm), body length (L, cm) and live BW of each animal were also registered. At each selected age, animals were slaughtered, ground and frozen (-20 ºC) for later chemical analyses (DM, fat, CP, ash and GE). Fat and energy body content increased with the age, while protein, ash, and water decreased. Mean values of Rs, Xc, impedance (Z), L and D were 83.5 ± 23.1 , 18.2 ± 3.8 , 85.6 ± 22.9 , 30.6 ± 6.9 cm and 10.8 ± 3.1 cm. A multiple linear regression analysis was used to determine the prediction equations, using BW, L and Z data as independent variables. Equations obtained to estimate water (g), CP (g), fat (g), ash (g) and GE (MJ) content had, respectively, coefficient of determination (R2) values of 0.99, 0.99, 0.97, 0.98 and 0.99, and the relative mean prediction error (RMPE) was: 2.79, 6.15, 24.3, 15.2 and 10.6%, respectively. When water was expressed as percentage, the R2 and RMPE were 0.85 and 2.30%, respectively. When prediction of the content of protein (%DM), fat (%DM), ash (%DM) and energy (kJ/100 g DM) was done, values of 0.79, 0.83, 0.71 and 0.86 for R2, and 5.04, 18.9, 12.0 and 3.19% for RMPE, respectively, were obtained. Reactance was negatively correlated with water, ash and CP content (r = -0.32, P < 0.0001; r = -0.20, P < 0.05; r = -0.26, P < 0.01) and positively correlated with fat and GE (r = 0.23 and r = 0.24; P < 0.01). Otherwise, resistance was positively correlated with water, ash and CP (r = 0.31, P < 0.001; r = 0.28, P < 0.001; r = 0.37, P < 0.0001) and negatively correlated with fat and energy (r = -0.36 and r = -0.35; P < 0.0001). Moreover, age was negatively correlated with water, ash and CP content (r = -0.79; r = -0.68 and r = -0.80; P < 0.0001) and positively correlated with fat and energy (r = 0.78 and r = 0.81; P < 0.0001). It could be concluded that BIA is a non-invasive good method to estimate in vivo whole body composition of growing rabbits from 25 to 77 days of age. The aim of the second study was to determine and validate with independent data, the prediction equations obtained to estimate in vivo carcass composition of growing rabbits by using the results of carcass chemical composition and BIA values in a group of rabbits from 25 to 77 days. Also its potential application to predict nutrient retention and overall energy and nitrogen retention efficiencies was analysed. Seventy five rabbits grouped at 5 different ages (25, 35, 49, 63 and 77 days) with weights ranging from 196 to 3260 g were used. A four terminal body composition analyser (Model BIA-101, RJL Systems, Detroit, MI USA) was used to obtain resistance (Rs, ) and reactance (Xc, ) values. The distance between internal electrodes (D, cm), body length (L, cm) and live weight (BW, g) were also registered. At each selected age, all the animals were stunned and bled. The skin, organs and digestive content were removed, and the chilled carcass were weighed and processed for chemical analyses (DM, fat, CP, ash and GE). Energy and fat increased with the age, while CP, ash, and water decreased. Mean values of Rs, Xc, impedance (Z), L and D were 95.9±23.9 , 19.5±4.7 , 98.0±23.8 , 20.6±6.3 cm y 13.7±3.1 cm. A multiple linear regression analysis was done to determine the equations, using BW, L and Z data as parameters. Coefficient of determination (R2) of the equations obtained to estimate water (g), CP (g), fat (g), ash (g) and GE (MJ) content were: 0.99, 0.99, 0.95, 0.96 and 0.98, and relative mean prediction error (RMPE) were: 4.20, 5.48, 21.9, 9.10 and 6.77%, respectively. When water content was expressed as percentage, the R2 and RMPE were 0.79 and 1.62%, respectively. When prediction of protein (%DM), fat (%DM), ash (%DM) and energy (kJ/100 g DM) content was done, R2 values were 0.68, 0.76, 0.66 and 0.82, and RMPE: 3.22, 10.5, 5.82 and 2.54%, respectively. Reactance was positively correlated with fat content (r = 0.24, P < 0.05) while resistance was positively correlated with water, ash and protein carcass content (r = 0.55, P < 0.001; r = 0.54, P < 0.001; r = 0.40, P < 0.005) and negatively correlated with fat and energy (r = -0.44 and r = -0.55; P < 0.001). Moreover, age was negatively correlated with water, ash and CP content (r = -0.97, r = -0.95 and r = -0.89, P < 0.0001) and positively correlated with fat and GE (r = 0.95 and r = 0.97; P < 0.0001). In the whole growing period (35-63 d), overall energy retention efficiency (ERE) and nitrogen retention efficiency (NRE) were studied. The ERE values were 20.4±7.29%, 21.0±4.18% and 20.8±2.79%, from 35 to 49, 49 to 63 and from 35 to 63 d, respectively. NRE was 46.9±11.7%, 34.5±7.32% and 39.1±3.23% for the same periods. Energy was retained in body tissues for growth with an efficiency of approximately 52.5% and efficiency of the energy for protein and fat retention was 33.3 and 69.9%, respectively. Efficiency of utilization of nitrogen for growth was near to 77%. This work shows that BIA it’s a non-invasive and good method to estimate in vivo carcass composition and nutrient retention of growing rabbits from 25 to 77 days of age. In the third study, two experiments were conducted to investigate the effect of the fat addition and source, on performance, mortality, nutrient retention, and the whole body and carcass chemical composition of growing rabbits from 34 to 63 d. In Exp. 1 three diets were arranged in a 3 x 2 factorial structure with the source of fat: Soybean oil (SBO), Soya Lecithin Oil (SLO) and Lard (L) and the dietary fat inclusion level (1.5 and 4%) as the main factors. Exp. 2 had also arranged as a 3 x 2 factorial design, but using SBO, Fish Oil (FO) and Palmkernel Oil (PKO) as fat sources, and included at the same levels than in Exp. 1. In both experiments 180 animals were allocated in individual cages (n=30) and 600 in collectives cages, in groups of 5 animals (n=20). Animals fed with 4% dietary fat level showed lower DFI and FCR than those fed diets with 1.5%. In collective housing of Exp. 1, DFI was a 4.8% higher in animals fed with diets containing lard than SBO (P = 0.036), being intermediate for diet with SLO. Inclusion of lard also tended to reduce mortality (P = 0.067) around 60% and 25% with respect SBO and SLO diets, respectively. Mortality increased with the greatest level of soya lecithin (14% vs. 1%, P < 0.01). In Exp. 2 a decrease of DFI (11%), BW at 63 d (4.8%) and DWG (7.8%) were observed with the inclusion of fish oil with respect the other two diets (P < 0.01). These last two traits impaired with the highest level of fish oil (5.6 and 9.5%, respectively, (P < 0.01)). Animals housed individually showed similar performance results. The inclusion of fish oil also tended to increase (P = 0.078) mortality (13.2%) with respect palmkernel oil (6.45%), being mortality of SBO intermediate (8.10%). Fat source and level did not affect the whole body or carcass chemical composition. An increase of the fat sources addition led to a decrease of the digestible nitrogen intake (DNi) (1.83 vs. 1.92 g/d; P = 0.068 in Exp. 1 and 1.79 vs. 1.95 g/d; P = 0.014 in Exp. 2). As the nitrogen retained (NR) in the carcass was similar for both fat levels (0.68 g/d (Exp. 1) and 0.71 g/d (Exp. 2)), the overall efficiency of N retention (NRE) increased with the highest level of fat, but only reached significant level in Exp. 1 (34.9 vs. 37.8%; P < 0.0001), while in Exp. 2 a tendency was found (36.2 vs. 38.0% in Exp. 2; P < 0.064). Consequently, nitrogen excretion in faeces was lower in animals fed with the highest level of fat (0.782 vs. 0.868 g/d; P = 0.0001 in Exp. 1, and 0.745 vs. 0.865 g/d; P < 0.0001 in Exp.2). The same effect was observed with the nitrogen excreted as urine (0.702 vs. 0.822 g/d; P < 0.0001 in Exp. 1 and 0.694 vs. 0.7999 g/d; P = 0.014 in Exp.2). Although there were not differences in ERE, the energy excreted in faeces decreased as fat level increased (142 vs. 156 Kcal/d; P = 0.0004 in Exp. 1 and 144 vs. 154 g/d; P = 0.050 in Exp. 2). In Exp. 1 the energy excreted as urine and heat production was significantly higher when animals were fed with the highest level of dietary fat (216 vs. 204 Kcal/d; P < 0.017). It can be concluded that lard and palmkernel oil can be considered as alternative sources to soybean oil due to the reduction of the mortality, without negative effects on performances or nutrient retention. Inclusion of fish impaired animals´ productivity and mortality. An increase of the dietary fat level improved FCR and overall protein efficiency retention.

Hydrolysis of lignocellulosic material to sugars as feedstock for growing microorganisms

Los materiales lignocelulósicos son potenciales precursores de recursos bioenergéticos, por lo que sería interesante desarrollar tecnologías capaces de capturar su energía y utilizarla en el sector del transporte como combustibles. El azúcar contenido en los materiales lignocelulósicos puede ser liberado por medio de la hidrólisis y usado después por microorganismos. El objetivo del proyecto es encontrar un método de separación de la celulosa y la biomasa de chopo en monómeros de glucosa por medio de la hidrólisis. Para ello se han estudiado tres métodos de hidrólisis: la mecano-catálisis, utilizando diferentes tipos de molinos y caolinita como catalizador, la hidrólisis con líquidos iónicos, estudiando la viabilidad de los reactivos [C4mim+][I-] y [C4mim+][PF6-], y la hidrólisis ácida, usando HCl en concentraciones y temperaturas distintas para optimizar el proceso. En todos los casos se ha llevado a cabo un pretratamiento y se ha aplicado el método de TLC como verificación del proceso. Los tres métodos se han comparado y se ha desarrollado un método de correlación entre la mancha de TLC y la concentración del producto.

Long-range signaling within growing neurites mediated by neurotrophin-3

In addition to well established trophic functions, neurotrophins acutely affect neurotransmitter secretion from the presynaptic nerve terminal, influence synaptic development, and may serve as selective retrograde messengers that regulate synaptic efficacy. The crucial question related to the mechanisms of neurotrophin-mediated signaling is whether acute effects of neurotrophins are spatially restricted to the activated synapses. Here we have used a local perfusion technique for local delivery of neurotrophin-3 (NT-3) to various regions of developing Xenopus embryo neurons in culture. Within minutes after a focal exposure of a soma or a small (≈30 μm in length) axonal segment to NT-3, we observed an increase in the spontaneous neurotransmitter secretion from the presynaptic nerve terminals located ≈300–400 μm away from the site of NT-3 application. Secretory activity along the axonal shaft was not affected. Our findings suggest that the NT-3-mediated signal may rapidly travel through neuronal cytoplasm over unexpectedly long distances and modulate neurotransmitter release specifically at the presynaptic nerve terminals.

Environmental costs and benefits of growing Miscanthus for bioenergy in the UK

Funded by BBSRC. Grant Number: LK0863 Natural Environment Research Council (NERC) Carbo-BioCrop project. Grant Number: NE/H01067X/1 MAGLUE project