Nellore metabolism receiving exogenous amylase in high-concentrate diets.

The objective of this study was to evaluate the effects of supplementation with exogenous enzyme of Aspergillus oryzae (primarily alpha amylase) in high-concentrate feedlot diets on blood and ruminal parameters of Nellore cattle. Ten Nellore bulls with rumen fistulae, initial body weight between 350 to 400 kg and age of 24 months were housed in individual pens. The experimental design was crossover, in which the animals were randomized between treatments 1: Control - absence of amylase and 2: Amylase -Aspergillus oryzae extract containing alpha amylase activity (Amaize®, Alltech, Inc.), 5 g/animal daily. There was an initial adjustment period (25 days) and a data-collection period (25 days); after, there was rest period (25 days), then the treatments were reversed and the adjustment and collection periods repeated. The diet was composed of: sugar cane bagasse (12% DM), corn (62% DM), citrus pulp (17% DM), soybean meal (4.7% DM), Optigen®, a controlled-relaease urea (1.1% DM) and mineral salt (3.2% DM). The parameters evaluated were plasma concentrations of insulin, glucose, and beta-hydroxybutyrate plus molar proportions of volatile fatty acids (VFA), pH and ammonia concentration in rumen fluid. The data were analyzed using the MIXED procedure of SAS (9.0), considering the effects of treatment, time and random animals, with P < 0.10 declared significant. As shown in Table 649, plasma insulin concentrations were reduced in animals receiving Amylase (16.9 vs 27.8 μIU/mL; P = 0.06), as well as acetate and acetate:propionate to the same animals, while the propionate was higher in animals receiving Amylase (18.8 vs 20.4 molar proportion; P = 0.03). In conclusion, exogenous amylase can reduce insulin levels in the animals' blood and also cause effect on ruminal parameters. Acknowledgments: Alltech and FAPESP. [ABSTRACT FROM AUTHOR]