An improved survival model of hypoxia/ischaemia in the piglet suitable for neuroprotection studies

The purpose of this study, was to develop a newborn piglet model of hypoxia/ischaemia which would better emulate the clinical situation in the asphyxiated human neonate and produce a consistent degree of histopathological injury following the insult. One-day-old piglets (n = 18) were anaesthetised with a mixture of propofol (10 mg/kg/h) and alfentinal (5,5.5 mug/kg/h) i.v. The piglets were intubated and ventilated. Physiological variables were monitored continuously. Hypoxia was induced by decreasing the inspired oxygen (FiO(2)) to 3-4% and adjusting FiO(2) to maintain the cerebral function monitor peak amplitude at less than or equal to5 muV. The duration of the mild insult was 20, min while the severe insult was 30 min which included 10 min where the blood pressure was allowed to fall below 70% of baseline. Control piglets (n=4 of 18) were subjected to the same protocol except for the hypoxic/ischaemic insult. The piglets were allowed to recover from anaesthesia then euthanased 72 It after the insult. The brains were perfusion-fixed, removed and embedded in paraffin. Coronal sections were stained by haematoxylin/eosin. A blinded observer examined the frontal and parietal cortex, hippocampus, basal ganglia, thalamus and cerebellum for the degree of damage. The total mean histology score for the five areas of the brain for the severe insult was 15.6 +/-4.4 (mean +/-S.D., n=7), whereas no damage was seen in either the mild insult (n=4) or control groups. This 'severe damage' model produces a consistent level of damage and will prove useful for examining potential neuroprotective therapies in the neonatal brain. (C) 2001 Elsevier Science BY. All rights reserved.

Noninvasive measurement of cerebral bioimpedance for detection of cerebral edema in the neonatal piglet

The association of sustained cerebral edema with poor neurological outcome following hypoxia-ischaemia in the neonate suggests that measurement of cerebral edema may allow early prediction of outcome in these infants. Direct measurements of cerebral impedance have been widely used in animal studies to monitor cerebral edema, but such invasive measurements are not possible in the human neonate. This study investigated the ability of noninvasive cerebral impedance measurements to detect cerebral edema following hypoxia-ischaemia. One-day-old piglets were anaesthetized, intubated and ventilated. Hypoxia was induced by reducing the inspired oxygen concentration to 4-6% O-2. Noninvasive cerebral bioimpedance was measured using gel electrodes attached to the scalp. Cerebral bioimpedance was also measured directly by insertion of two silver-silver chloride electrodes subdurally. Noninvasive and invasive measurements were made before, during and after hypoxia. Whole body impedance was measured to assess overall fluid movements. Intracranial pressure was measured continuously via a catheter inserted subdurally, as an index of cerebral edema. There was good agreement between noninvasive and invasive measurements of cerebral impedance although externally obtained responses were attenuated. Noninvasive measurements were also well correlated with intracranial pressure. Whole body impedance changes did not account for increases in noninvasively measured cerebral impedance. Results suggest that noninvasive cerebral impedance measurements do reflect intracranial events, and are able to detect cerebral edema following hypoxia-ischaemia in the neonate. (C) 2002 Elsevier Science B.V. All rights reserved.

Experimental Infection of Swine by Isospora suis Biester 1934 for Species Confirmation

A survey of Isospora suis performed in 177 faecal samples from 30 swine farms detected thin wall type I. suis oocysts in seven samples. This type of oocyst measuring 23.9 by 20.7 mm had a retracted thin wall similar to that of the genus Sarcocystis. This type of oocysts, isolated from four different faecal samples, was inoculated in four-five-days-old piglets free of contamination in order to verify the life cycle and pathogenicity of the species. The pigs were kept in individual metal cages and fed with cow milk. Daily faecal collections and examinations were performed until the 21st day after infection. MacMaster and Sheather' s methods were used for oocyst counting and identification. Infected piglets produced yellowish-pasty diarrhoea with slight dehydration. The prepatent and patent periods were respectively from 6 to 9 and 3 to 10 days after infection. Oocyst elimination was interrupted on the 10th and 11th days after infection with biphasic cycles. Thin and thick wall oocysts were detected in the same faecal samples. Thin walls were not observed in unsporulated oocysts. The observations suggest that this type of oocysts could appear in specific strains which occur in the later stages of their development. These oocysts seem to be responsible for clinical and pathogenic signs of neonatal isosporosis in pigs.

Application of ZnO-Functionalised-Sepiolite in weaning piglet diets

The objective was to evaluate the effect of ZnO-Functionalised-Sepiolite (ZnO-Sepiolite) to fulfil Zn requirements and health status of weaning piglets. Pre-starter Basal Diet (BD, corn– soybean based, from weaning till 14 days on trial) was calculated to provide 27 mg Zn/kg feed from raw materials and had no added ZnO and no antibiotics or organic acids. Treatments during pre-starter period were: 1) BD+90% of NRC Zn requirements completed with ZnO (ZnO90); 2) BD+90% of NRC Zn requirements completed with ZnO-Sepiolite (ZnOS90); 3) BD+3000 mg ZnO/kg of diet (ZnO3000); 4) BD+150 mg added Zn/kg diet from ZnO-Sepiolite (ZnOS150). The starter feed (corn–soybean based, from 14 till 31 days on trial) was common for all piglets, and met 90% NRC Zn requirements by adding ZnO. Diarrhea affected more than 50% of the animals of ZnO90, ZnOS90 and ZnOS150, and 33% of the ZnO3000 animals. Animals from ZnOS90 tended (Pb0.10) to improve Gain to Feed ratio (G:F) compared to animals from ZnO90 (0.830 kg/kg vs. 0.811 kg/kg for G:F). Performance of animals from ZnO3000 was not significantly different from the other treatments, and was numerically similar to animals from ZnOS90. The inclusion of ZnO at 3000 mg/kg of feed in the pre-starter period numerically decreased P in serum at the end of this period, with no effect on Ca level; normal levels were restored after 2 weeks of feeding the same levels of Zn than other animals. Animals fed ZnOSepiolite diets had numerically higher serum Ca than ZnO90 and ZnO3000 at 12 days and higher than ZnO90 at 28 days. Serum Zn levels were significantly higher for ZnO3000 than the other treatments.

Clostridium difficile ribotypes in humans and animals in Brazil

Clostridium difficile is an emerging enteropathogen responsible for pseudomembranous colitis in humans and diarrhoea in several domestic and wild animal species. Despite its known importance, there are few studies aboutC. difficile polymerase chain reaction (PCR) ribotypes in Brazil and the actual knowledge is restricted to studies on human isolates. The aim of the study was therefore to compare C. difficileribotypes isolated from humans and animals in Brazil. Seventy-six C. difficile strains isolated from humans (n = 25), dogs (n = 23), piglets (n = 12), foals (n = 7), calves (n = 7), one cat, and one manned wolf were distributed into 24 different PCR ribotypes. Among toxigenic strains, PCR ribotypes 014/020 and 106 were the most common, accounting for 14 (18.4%) and eight (10.5%) samples, respectively. Fourteen different PCR ribotypes were detected among human isolates, nine of them have also been identified in at least one animal species. PCR ribotype 027 was not detected, whereas 078 were found only in foals. This data suggests a high diversity of PCR ribotypes in humans and animals in Brazil and support the discussion of C. difficile as a zoonotic pathogen.

A bi-dimensional genome scan for prolificacy traits in pigs shows the existence of multiple epistatic QTL

Background: Prolificacy is the most important trait influencing the reproductive efficiency of pig production systems. The low heritability and sex-limited expression of prolificacy have hindered to some extent the improvement of this trait through artificial selection. Moreover, the relative contributions of additive, dominant and epistatic QTL to the genetic variance of pig prolificacy remain to be defined. In this work, we have undertaken this issue by performing one-dimensional and bi-dimensional genome scans for number of piglets born alive (NBA) and total number of piglets born (TNB) in a three generation Iberian by Meishan F2 intercross. Results: The one-dimensional genome scan for NBA and TNB revealed the existence of two genome-wide highly significant QTL located on SSC13 (P < 0.001) and SSC17 (P < 0.01) with effects on both traits. This relative paucity of significant results contrasted very strongly with the wide array of highly significant epistatic QTL that emerged in the bi-dimensional genome-wide scan analysis. As much as 18 epistatic QTL were found for NBA (four at P < 0.01 and five at P < 0.05) and TNB (three at P < 0.01 and six at P < 0.05), respectively. These epistatic QTL were distributed in multiple genomic regions, which covered 13 of the 18 pig autosomes, and they had small individual effects that ranged between 3 to 4% of the phenotypic variance. Different patterns of interactions (a × a, a × d, d × a and d × d) were found amongst the epistatic QTL pairs identified in the current work.Conclusions: The complex inheritance of prolificacy traits in pigs has been evidenced by identifying multiple additive (SSC13 and SSC17), dominant and epistatic QTL in an Iberian × Meishan F2 intercross. Our results demonstrate that a significant fraction of the phenotypic variance of swine prolificacy traits can be attributed to first-order gene-by-gene interactions emphasizing that the phenotypic effects of alleles might be strongly modulated by the genetic background where they segregate.

Efecto de la suplementación con ácidos grasos de cadena media sobre la evolución de peso en lechones con poco peso al nacimiento

La evolución de peso en los períodos de lactación y transición de 583 lechones fue estudiada mediante un análisis estadístico, evaluando el efecto de la suplementación con ácidos grasos de cadena media (AGCM) en lechones con poco peso al nacimiento. 188 de los 375 lechones que nacieron con un peso al nacimiento (PN) &1250 g recibieron 3mL de AGCM cada 24 h durante los primeros 3 días de vida; su peso medio al destete (día 28) fue inferior respecto al grupo control (lechones no suplementados) (-114,17 g). No obstante, 106 de los 180 lechones nacidos con un PN &1000 g fueron suplementados, y su peso medio al destete y a finales de transición (día 63) fue superior respecto al grupo control (destete: +315,16 g; día 63: +775,47 g). Finalmente, los lechones suplementados con PN&800 g tuvieron los peores resultados: su diferencia de peso medio al destete fue de -177,58 g respecto al grupo control. Por lo tanto, en esta prueba fueron estudiados los lechones con un PN entre 800 y 999 g porque el grupo suplementado al destete tuvo una diferencia de peso medio considerable respecto al grupo control:+511,58 g. Asimismo, considerando una probabilidad de error inferior a 0,05, no hubieron diferencias significativas en las diferentes categorías de PN analizadas. De todas maneras, es importante destacar el alto grado de significación en la suplementación con AGCM en lechones con PN entre 800 y 999g (P=0,059). Por otra parte, el PN del grupo suplementado con PN&1000 g fue inferior que el del grupo no suplementado con PN&1000 g; esta diferencia de PN fue significativa (P=0,004) y como consecuencia el grado de significación en la suplementación con AGCM en lechones con PN entre 800 y 999 g fue inferior al esperado. Además, en esta prueba se incluyeron algunos resultados generales y también un análisis simple de supervivencia, aunque no era el objetivo principal

Rapid cohort generation and analysis of disease spectrum of large animal model of cone dystrophy.

Large animal models are an important resource for the understanding of human disease and for evaluating the applicability of new therapies to human patients. For many diseases, such as cone dystrophy, research effort is hampered by the lack of such models. Lentiviral transgenesis is a methodology broadly applicable to animals from many different species. When conjugated to the expression of a dominant mutant protein, this technology offers an attractive approach to generate new large animal models in a heterogeneous background. We adopted this strategy to mimic the phenotype diversity encounter in humans and generate a cohort of pigs for cone dystrophy by expressing a dominant mutant allele of the guanylate cyclase 2D (GUCY2D) gene. Sixty percent of the piglets were transgenic, with mutant GUCY2D mRNA detected in the retina of all animals tested. Functional impairment of vision was observed among the transgenic pigs at 3 months of age, with a follow-up at 1 year indicating a subsequent slower progression of phenotype. Abnormal retina morphology, notably among the cone photoreceptor cell population, was observed exclusively amongst the transgenic animals. Of particular note, these transgenic animals were characterized by a range in the severity of the phenotype, reflecting the human clinical situation. We demonstrate that a transgenic approach using lentiviral vectors offers a powerful tool for large animal model development. Not only is the efficiency of transgenesis higher than conventional transgenic methodology but this technique also produces a heterogeneous cohort of transgenic animals that mimics the genetic variation encountered in human patients.

Raudan imeytyminen ja paikallinen kudosärsytys porsailla lihaksensisäisen tai nahanalaisen rautadekstraani-injektion jälkeen

Summary: Absorption of iron and local tissue irritation after intramuscular or subcutaneous administration of an iron-dextran preparation to piglets

The effect of age at the first mating and herd size on the lifetime productivity of sows

The effect of age at the first mating and herd size were evaluated in the reference Spanish Databank (BDporc) of 37 698 sows born between 1991 and 1995 and with individual lifetime records. The data included dates of births at entrance and culling, first mating, repetitive mating and conception, first farrowing and weaning records. Individual records were validated before the analysis by screening them through a tolerance “filter” in order to eliminate the extreme values from the analysis. The total database of the sows was classified in 7 classes according to age at the first mating (< 210, 210–220, 221–230, 231–240, 241–250, 251–270, and > 270 days) and in 6 classes of herd size (< 200, 200–300, 301–400, 401–600, 601–800, and > 800 sows). The total number of litters and number of weaned piglets obtained from each sow during the lifetime production were significantly (P < 0.05) greater for gilts between 221 and 240 d of age at the first mating. There was a significant (P < 0.001) effect of the herd size on the reproductive performance of the sow, and the best performance was obtained with herds with 401 to 600 sows compared to < 200 or > 800 sow-herds. Furthermore, a significant (P < 0.001) interaction between age at the first mating and herd size was detected and can be associated with a particular pattern for the herd size class 401–600 sows with the best performances obtained for the sows first mated at less than 200 days. For the other herd sizes, the results indicated that sows mated for the first time at the right age, 221–240 days, are more productive, both in the number and size of the parities throughout lifetime production.

Estimación de los efectos del manejo reproductivo y su influencia en la selección del tamaño de la camada en porcino

Con datos procedentes de poblaciones de campo (37.920 partos porducidos en granjas de selección y 95.240 partos producidos en granjas de producción) se ha analizado la influencia de la edad al primer parto, de la duración de la lactación, de la duración del intervalo destete-cubrición fértil y del tipo de cubrición fértil sobre el número de lechones nacidos vivos por parto (NV). Además, utilizando datos simulados se ha evaluado el interés de considerar estos factores de manejo en el modelo de evaluación genética para NV. Los factores de manejo analizados influyen de forma significativa (P < 0,05) sobre NV, en magnitud y sentido similar en las poblaciones de selección y de producción. Mediante simulación se comprueba que omitir la influencia de los factores de manejo anteriores en el modelo de evaluación genética no interfiere en la respuesta a la selección, aunque puede conducir a la obtención de predictores sesgados del valor genético.

Efecto de la suplementación con ácidos grasos de cadena media sobre la evolución de peso en lechones con poco peso al nacimiento

La evolución de peso en los períodos de lactación y transición de 583 lechones fue estudiada mediante un análisis estadístico, evaluando el efecto de la suplementación con ácidos grasos de cadena media (AGCM) en lechones con poco peso al nacimiento. 188 de los 375 lechones que nacieron con un peso al nacimiento (PN) <1250 g recibieron 3mL de AGCM cada 24 h durante los primeros 3 días de vida; su peso medio al destete (día 28) fue inferior respecto al grupo control (lechones no suplementados) (-114,17 g). No obstante, 106 de los 180 lechones nacidos con un PN <1000 g fueron suplementados, y su peso medio al destete y a finales de transición (día 63) fue superior respecto al grupo control (destete: +315,16 g; día 63: +775,47 g). Finalmente, los lechones suplementados con PN<800 g tuvieron los peores resultados: su diferencia de peso medio al destete fue de -177,58 g respecto al grupo control. Por lo tanto, en esta prueba fueron estudiados los lechones con un PN entre 800 y 999 g porque el grupo suplementado al destete tuvo una diferencia de peso medio considerable respecto al grupo control:+511,58 g. Asimismo, considerando una probabilidad de error inferior a 0,05, no hubieron diferencias significativas en las diferentes categorías de PN analizadas. De todas maneras, es importante destacar el alto grado de significación en la suplementación con AGCM en lechones con PN entre 800 y 999g (P=0,059). Por otra parte, el PN del grupo suplementado con PN<1000 g fue inferior que el del grupo no suplementado con PN<1000 g; esta diferencia de PN fue significativa (P=0,004) y como consecuencia el grado de significación en la suplementación con AGCM en lechones con PN entre 800 y 999 g fue inferior al esperado. Además, en esta prueba se incluyeron algunos resultados generales y también un análisis simple de supervivencia, aunque no era el objetivo principal

Behavior, performance and physiological parameters of pigs reared in deep bedding

An experiment was conducted to evaluate the behavior, performance and physiological parameters of pigs in different production systems. Twenty four animals in the growth phase were distributed in a randomized block design in three treatments: T1 - concrete floor, T2 - deep bedding with wood shaving, and T3 - deep bedding with coffee husks. The behavioral study was carried out by observing the animal behavior for an uninterrupted period of eight hours throughout seven weeks. The proportions of time spent in each behavior were characterized using the frequency histogram composition. Environmental (IBGTH), physiological (rectal and skin temperature and respiratory rate) and performance (weight gain, feed intake and feed conversion) parameters were measured in animals during the period. The production systems of deep bedding showed higher values of IBGTH. There was no effect of production systems evaluated on the performance parameters. Rectal temperature was higher in animals reared on deep bedding with coffee husks in relation to the concrete floor. The use of deep bedding benefited the behavior of piglets in the growth phase and it reduced the agonistic behavior among individuals.

Energetic efficiency of a deep bed swine production system

The aim of this work was to evaluate the energy flows of a commercial production system of swine deep bed in its finishing phase, located in Juiz de Fora, in the State of Minas Gerais, Brazil. Thus, an energy efficiency study was carried out by monitoring a lot of animals, during a 94-day period. The energy rate of each compound involved in the production process was quantified and the matrixes of energy consumption were determined in the form of animal feeding, electrical energy, piglets, material used as deep bed, human labor, equipment, swine buildings, production of alive swine for slaughter, organic fertilizer production (swine deep bed or swine deep litter). From the direct input energy, 80.57% correspond to animal feeding, 11.90% to pigs for slaughter and 6.76% to piglets, while from the energy output 53.45% correspond to the terminating swine and 46.55% to organic fertilizer (swine deep bed). By the results obtained, we can conclude that such production system has corresponded to an industrial and highly specialized agro ecosystem, importing a great part of the energy consumed in the production process, with 41% of energy efficiency.

Energy expenditure in vocalizations of pigs under stress

Modern swine production faces many challenges nowadays, among which are productivity growth, meat quality improvement, decrease of environmental damage and reduction of cost production. Pigs spend energy to vocalizing, especially when they undergo stress. The waste of energy can increase the cost of production and lead to greater environmental damage. The goal of this study was to estimate the energy spent by pigs under the stress of castration and its effect on the animals' weight gain. Two groups of ten animals each were castrated, being one group with local anesthetic and the other without anesthetic. The piglets' vocalizations were recorded during different stages of the neutering process and then estimated of the amount of energy emitted during each vocalization. Afterwards, this energy was associated with the animals' weight gain. There was no difference in the total energy spent in both groups, since the energy used during the application of anesthetic was similar to the energy spent during the castration of the animals without anesthetic. There was also no correlation between energy spent and the animals' weight gain. It was possible to estimate the amount of energy emitted through vocalization. This energy spent by piglets in pain was greater than in other handling situations (contention, weighting and realease).