Efecto de diferentes concentraciones de Taninos sobre la flora microbiana ruminal y en la degradabilidad in vitro del forraje de alfalfa.

Tesis (Maestría en Ciencias en Producción Animal) UANL

Uso de técnicas isotópicas de 15 N aplicadas al estudio de la fijación biológica de nitrógeno en el cultivo de alfalfa (Medicago sativa L.) en La Comarca Lagunera, México

Tesis (Maestría en Ciencias con Especialidad en Microbiología) UANL

Influence of exogenous fibrolytic enzyme level and incubation pH on the in vitro ruminal fermentation of alfalfa stems

A series of in vitro experiments was carried out to examine the impact of enzyme application rate and incubation medium pH on the rate and extent of fermentation of alfalfa stems. In Experiment 1, a commercial enzyme product (Liquicell 2500, Specialty Enzyme and Biochemicals, Fresno, CA, USA) was added to alfalfa stems at six levels: 0, 0.51, 1.02, 2.55, 5.1, and 25.5 mu l/g (control and L1-L5, respectively) to forage DM in a completely randomized design, with a factorial arrangement of treatments. Rate and extent of fermentation and apparent organic matter degradation (OMD) were determined in vitro, using a gas production technique. Addition of enzyme linearly increased (P < 0.01) gas production for up to 12 h (68.9, 70.9, 67.6, 67.9, 71.9, and 74.9 ml/g OM for control, L1-L5, respectively) and OMD for up to 19 h incubation (0.425, 0.444, 0.433, 0.446, 0.443, and 0.451 for control, L1-L5, respectively), but no increases (P > 0.05) were detected thereafter. In Experiment 2, the effect of the same enzyme as used previously (added at 0.51 mu l/g forage DM, directly into the incubation medium), and buffer pH were examined using the ANKOM system, in a completely randomized design. Incubation medium pH was altered using 1 M citric acid, in order to obtain target initial pH values of 6.8 (control, no citric acid added), 6.2, 5.8, and 5.4. Actual initial pH values achieved were 6.72, 6.50, 6.20, and 5.72. Lowering the pH decreased (P < 0.01) dry matter disappearance (DMD) at 18 h incubation (0.339, 0.341, 0.314, and 0.291 for 6.72, 6.50, 6.20, and 5.72, respectively), whereas enzyme addition increased (P < 0.05) DMD at 24 h (0.363 versus 0.387 for control and enzyme-treated, respectively). Addition of enzyme increased (P < 0.05) neutral detergent fibre (NDF), acid detergent fibre (ADF), and hemicellulose (HC) degradation at pH 6.50 (0.077 versus 0.117; 0.020 versus 0.051; 0.217 versus 0.270 for control and enzyme-treated NDF, ADF and hemicellulose degradation, respectively) and 6.72 (0.091 versus 0.134; 0.041 versus 0.079; 0.205 versus 0.261 for control and enzyme-treated NDF, ADF and HC degradation, respectively). It is concluded that the positive effects of this enzyme product were independent of the pre-treatment period, but pH influenced the responses to enzyme supplementation. Under the conditions of this experiment, exogenous fibrolytic enzymes seemed to work better at close to neutrality ruminal pH conditions. (C) 2006 Elsevier B.V. All rights reserved.

Splanchnic metabolism of nitrogenous compounds and urinary nitrogen excretion in steers fed alfalfa under conditions of increased absorption of ammonia and L-arginine supply across the portal-drained viscera

Effects of increased ammonia and/or arginine absorption across the portal-drained viscera (PDV) on net splanchnic (PDV and liver) metabolism of nitrogenous compounds and urinary N excretion were investigated in six cathetenzed Hereford x Angus steers (501 +/- 1 kg BW) fed a 75% alfalfa:25% (as-fed basis) corn-soybean meal diet (0.523 MJ of ME/[kg BW0.15.d]) every 2 h without (27.0 g of N/kg of dietary DM) and with 20 g of urea/kg of dietary DM (35.7 g of N/kg of dietary DM) in a split-plot design. Net splanchnic flux measurements were obtained immediately before beginning and ending a 72-h mesenteric vein infusion of L-arginine (15 mmol/h). For 3 d before and during arginine infusion, daily urine voided was measured and analyzed for N composition. Feeding urea increased PDV absorption (P < 0.01) and hepatic removal (P < 0.01) of ammonia N, accounting for 80% of increased hepatic urea N output (P < 0.01). Numerical increases in net hepatic removal of AA N could account for the remaining portion of increased hepatic urea N output. Arginine infusion increased hepatic arginine removal (P < 0.01) and hepatic urea N output (P < 0.03) and switched hepatic ornithine flux from net uptake to net output (P < 0.01), but numerical changes in net hepatic removal of ammonia and AA N could not account fully for the increase in hepatic urea N output. Increases in urine N excretion equaled quantities of N fed as urea or infused as arginine. Estimated salivary urea N excretion was not changed by either treatment. Urea cycle regulation occurs via a complex interaction of mechanisms and requires N sources other than ammonia, but the effect of increased ammonia absorption on hepatic catabolism of individual AA in the present study was not significant.

Splanchnic metabolism of nutrients and hormones in steers fed alfalfa under conditions of increased absorption of ammonia and L-arginine supply across the portal-drained viscera

Effects of increased ammonia and/or arginine absorption on net splanchnic (portal-drained viscera [PDV] plus liver) metabolism of nonnitrogenous nutrients and hormones in cattle were examined. Six Hereford x Angus steers (501 +/- 1 kg BW) prepared with vascular catheters for measurements of net flux across the splanchnic bed were fed a 75% alfalfa:25% (as-fed basis) corn and soybean meal diet (0.523 MJ of ME/[kg BW(0.75.)d]) every 2 h without (27.0 g of N/kg of DM) and. with 20 g of urea/kg of DM (35.7 g of N/kg of DM) in a split-plot design. Net flux measurements were made immediately before and after a 72-h mesenteric vein infusion Of L-arginine (15 mmol/h). There were no treatment effects on PDV or hepatic 02 consumption. Dietary urea had no effect on splanchnic metabolism of glucose or L-lactate, but arginine infusion decreased net hepatic removal Of L-lactate when urea was fed (P < 0.01). Net PDV appearance of n-butyrate was increased by arginine infusion (P < 0.07), and both dietary urea (P < 0.09) and arginine infusion (P < 0.05) increased net hepatic removal of n-butyrate. Dietary urea also increased total splanchnic acetate output (P < 0.06), tended to increase arterial glucagon concentration (P < 0.11), and decreased arterial ST concentration (P < 0.03). Arginine infusion increased arterial concentration (P < 0.07) and net PDV release (P < 0.10) and tended to increase hepatic removal (P < 0.11) of insulin, as well as arterial concentration (P < 0.01) and total splanchnic output (P < 0.01) of glucagon. Despite changes in splanchnic N metabolism, increased ammonia and arginine absorption had little measurable effect on splanchnic metabolism of glucose and other nonnitrogenous components of splanchnic energy metabolism.

Adaptation of Rhizobium leguminosarum to pea, alfalfa and sugar beet rhizospheres investigated by comparative transcriptomics

Background The rhizosphere is the microbe-rich zone around plant roots and is a key determinant of the biosphere's productivity. Comparative transcriptomics was used to investigate general and plant-specific adaptations during rhizosphere colonization. Rhizobium leguminosarum biovar viciae was grown in the rhizospheres of pea (its legume nodulation host), alfalfa (a non-host legume) and sugar beet (non-legume). Gene expression data were compared to metabolic and transportome maps to understand adaptation to the rhizosphere. Results Carbon metabolism was dominated by organic acids, with a strong bias towards aromatic amino acids, C1 and C2 compounds. This was confirmed by induction of the glyoxylate cycle required for C2 metabolism and gluconeogenesis in all rhizospheres. Gluconeogenesis is repressed in R. leguminosarum by sugars, suggesting that although numerous sugar and putative complex carbohydrate transport systems are induced in the rhizosphere, they are less important carbon sources than organic acids. A common core of rhizosphere-induced genes was identified, of which 66% are of unknown function. Many genes were induced in the rhizosphere of the legumes, but not sugar beet, and several were plant specific. The plasmid pRL8 can be considered pea rhizosphere specific, enabling adaptation of R. leguminosarum to its host. Mutation of many of the up-regulated genes reduced competitiveness for pea rhizosphere colonization, while two genes specifically up-regulated in the pea rhizosphere reduced colonization of the pea but not alfalfa rhizosphere. Conclusions Comparative transcriptome analysis has enabled differentiation between factors conserved across plants for rhizosphere colonization as well as identification of exquisite specific adaptation to host plants.

Selection of alfalfa cultivars adapted for tropical environments with repeated measures using PROC MIXED of SAS (R) System

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The effect of exogenous fibrolytic enzymes and a ferulic acid esterase-producing inoculant on the fibre degradability, chemical composition and conservation characteristics of alfalfa silage

The objective of this study was to determine the effect of applying fibrolytic enzymes at ensiling, either alone or in combination with a ferulic acid esterase-producing bacterial silage inoculant, on the silage conservation characteristics and nutritive value of alfalfa (Medicago sativa L). Second-cut alfalfa (340 g DM/kg fresh crop) was harvested, wilted, chopped and sub-sampled into 24 batches. Samples were randomly allocated in triplicate to one of four enzyme product treatments supplying endoglucanases and xylanases: none (control), EN1, EN2, EN3; applied alone or in combination with a ferulic acid esterase-producing silage inoculant (FAEI). Treatments were arranged in a 4 x 2 factorial design. All enzyme treatments were applied at 2 ml enzyme product/kg herbage DM, and inoculant was applied at 1 x 10(5) cfu/g fresh herbage. Samples were packed into laboratory-scale silos and stored for 7, 27 or 70 days, and analysed for dry matter (DM) losses, aerobic stability, chemical composition and in vitro ruminal degradability. The use of enzymes did not affect (P>0.05) ensilage DM losses or lactic or acetic acid concentrations after 70 days of ensilage, compared to the control silage. Silage produced using EN1 had lesser neutral detergent fibre (aNDF, P=0.046) and acid detergent fibre (ADF; P=0.006) concentrations than control silage. However, no difference (P>0.05) was observed between the control silage and silage produced with EN1 for aNDF or ADF degradability (NDFD, ADFD). Silages produced with FAEI had greater DM losses (P=0.017) and pH (P<0.001) and lesser NDFD (P=0.019), ADFD (P=0.010) and proportion of lactic acid in the total fermentation products (P=0.006) after 70 days of ensilage, compared to uninoculated silages. The use of fibrolytic enzymes did not have a major effect on the ensilage fermentation of alfalfa, either ensiled alone or with an inoculant. No advantage in ruminal DM or fibre degradability was observed for silages produced with fibrolytic enzymes. The use of a ferulic acid esterase-producing inoculant alone did not improve the nutritive value of alfalfa silage, and did not promote any incremental effects when applied in combination with fibrolytic enzyme products. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.

The chemical properties of soil for alfalfa production after biofertiliser application

The objective of this study was to evaluate the use of biofertilisers for the production of alfalfa shoot, root and nodule dry matter, and also, to evaluate the chemical properties of the soil. This study was conducted in the greenhouse of the Support Department, Animal Production and Health, Faculty of Veterinary Medicine/UNESP, Aracatuba - SP, from May to October 2010. The experimental design was completely randomised with six biofertiliser doses (0, 25, 50, 100, 200 and 400 m(3) ha(-1)) and five replicates. The biofertiliser doses were the primary treatments and the cuts (five) were subplots. The cuts were performed, on average, every 27 days at 10 cm above the soil. At the end of the experiment, the roots, nodules and soil from all experimental units were collected for chemical analysis. We observed a linear increase in dry matter production of the shoots relative to the doses studied. The dry matter production of the roots and nodules was not significantly different. The chemical properties of the soil significantly improved for calcium and magnesium as well as the sum of bases and base saturation with biofertiliser application. Biofertilisers can be used for agricultural production and favourably alter the soil characteristics.

Diurnal behavior of dairy cows on alfalfa pastures supplemented with corn silage and concentrate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NUTRITIONAL STATUS AND DRY MASS PRODUCTION OF ALFALFA IN FUNCTION OF POTASSIUM RATES IN TWO SOILS

Potassium fertilization is very important to alfalfa crop in terms of yield, quality and persistence of forage, especially on soils naturally poor K. Thus, to assess the effects of K fertilization in alfalfa production and nutritional status, was carried out an experiment in a greenhouse using samples of a Dystrophic Oxisol medium texture (LV) (0.6 mmol(c) dm(-3) K) and a Dystrophic Ultisol sandy/medium texture (PVA) (2.2 mmol(c) dm(-3) K). A completely randomized design in a factorial arrangement 6 x 2 (six K rates and two soils) was used, with four replications. The K rates used were: 0, 25, 50, 100, 150 and 200 mg kg(-1) K. Potassium fertilization increased K content in soil and shoots. Dry matter production was increased with the K addition. However, in the PVA, this occurred only in the second cut. In LV, potassium fertilization increased N concentration in alfalfa shoots in both cuts. Plants with K concentration around 10 g kg(-1) had typical symptoms of this nutrient deficiency. The K critical levels of K in soil and shoots were 1.8 mmolc dm(-3) and 16.7 g kg(-1), respectively.

Rendimento e qualidade do queijo tipo Minas Frescal de cabras alimentadas com raspa de mandioca e alfalfa

Pós-graduação em Zootecnia - FMVZ

Cow-Calf Production from Alfalfa-Grass or Smooth Bromegrass Pastures Rotationally Grazed at Three Stocking Rates

Pastures containing alfalfa-grass or smooth bromegrass were stocked with .6, .8, or 1.0 cow-calf units per acre to compare cow and calf production in rotational grazing systems managed for optimum forage quality. To remove excess forage early in the grazing season, yearling heifers or steers grazed with the cows in each pasture at a stocking rate of .6 ccu per acre for the first 28, 37, and 40 days of grazing in years one, two, and three. Live forage density and days of grazing per paddock were estimated by sward height. Cows, calves, and yearlings were weighed and cows condition scored every 28 days. All cows grazed for 140 days unless forage became limiting. The cows on the smooth bromegrass pasture stocked at 1.0 cow-calf units per acre were removed after 119 days in 1994, 129 days in 1995, and 125 days in 1996. Cows on one of the alfalfagrass pastures stocked at 1.0 ccu per acre were removed after 136 days of grazing in 1996 because of lack of forage. Alfalfa-grass pastures tended to have a more consistent supply of forage over the grazing season than the bromegrass pastures. Cows grazing the alfalfa-grass pastures had greater seasonal weight gains and body condition score increases and lower yearling weight gains than the smooth bromegrass pastures. Daily and total calf weight gains and total animal production also tended to be greater in alfalfa-cool season grass pastures. Increasing stocking rates resulted in significantly lower cow body condition increases and yearling weight gains, and also increased the amounts of calf and total growing animal produced.