Nutrients supply in wethers fed a tropical grass based-diet supplemented with levels of canola meal

Abstract

ResultsOnly cystine and methionine were significantly influenced by dietary methionine level but not with phytase level. This confirms the interrelationship between the cystine and methionine in the metabolism of the two amino acids. Also, threonine was significantly affected by only dietary methionine levels. There was no significant interaction between methoinine and phytase level. Though not significant, phytase addition led to numerical improvement in most of the amino acid digestibility. ConclusionThese results show that when methionine is marginally deficient in the diet of laying hens, addition of phytase could bring about numerical improvement in the AA digestibility which is not significant. This suggests that the inclusion level of methionine must be met even when phytase is to be used. AcknowledgementThe authors gratefully acknowledge the funding received from Alexander von Humboldt, Bonn, Germany. References IntroductionContinual growth of the biodiesel industry in Brazil has increased the availability of byproducts, such as canola meal (CM), for use in livestock feeding. However, the nutritional effects of CM supplementation for ruminants fed tropical grass based-diets need to be evaluated. This study evaluated the effect of offering canola meal as a supplementary feed on digestible organic matter intake, microbial protein synthesis, duodenal flux of amino acids and N retention in wethers fed a tropical grass based-diet. Materials and methodsEight Polwarth 3 Texel crossbreed wethers (31.1 6 3.8 kg live weight) housed in metabolism cages were used in a replicated 4 3 4 Latin Square experiment. Four of them were implanted with duodenal cannulae. Each experimental period was conducted over 15 d, with a 10 d adaptation and a 5 d measurement period. Wethers were fed a basal diet consisting of Sudangrass (Sorghum sudanense) ad libitum (100 to 200 g/kg of orts) and treatments were not supplementation (control) or supplementation with CM at a rate of 5, 10 or 15 g/Kg live weight. Forage and supplements were offered separately, in two daily meals, at 0800 and 1700 h. Cracked corn grain was added to CM (1:9) to improve palatability. Feed, refusals, urine and fecal output were recorded and sampled daily on days 10 to 15 of each experimental period. Duodenal sub-samples (100 mL) were taken on day 15 of each collection period in three hour intervals during a 24-h period. All samples were composited by animal and period. Feed, refusals, duodenal and feces samples were analysed for dry matter (DM), organic matter (OM), N and acid detergent lignin (ADL). Duodenal samples were also analysed for purines and a-amino N. Urine samples were analysed for N concentration. Duodenal flux of DM was estimated based on ADL concentration in duodenal digesta and feces as follows: Duodenal DM (g/day) 5 [fecal DM (g/day) 3 fecal ADL (g/kg of DM)]/duodenal ADL (g/kg of DM) (Porter & Singleton 1971). The amount of microbial N supplied to the small intestine (g/d) was calculated considering a ratio of purine N/microbial N of 0.116 (C...