Use of aspergillus oryzae extract containing alpha - amylase in feedlot diets for nellore cattle

Author(s)

Cleisy Ferreira do Nascimento

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2018-05-29.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2018-02-23
• Advisor: Flávio Dutra de Resende

Abstract

In diets with high levels of starch supplied to ruminants, the strategy to improve reduce underutilization of the concentrate is to optimize the digestibility. The digestion is enzyme-mediated by the rumen microorganisms, the addition of exogenous isoenzymes can enhance the use of diet. The objective of this study was to evaluate the effects use of Aspergillus oryzae extract containing alpha-amylase in feedlot diets on metabolism and performance of Nellore cattle. The study was in feedlot at the APTA experimental facility - Colina / SP / Brazil. Two distinct designs were used to evaluate metabolism (Exp. 1) and performance (Exp. 2). Exp. 1: Ten Nellore bulls, rumen cannulated (initial body weight between 400 ± 25 kg and age of 24 months) were housed in individual pens. The experimental design was crossover, in which the animals were randomized between two treatments 1: Control - absence of amylase and 2: Amylase -Aspergillus oryzae extract containing alpha amylase activity (Amaize®, Alltech, Inc,), 5 g/animal daily. The diet was isoprotein provided ad libitum, formulated to contain 2,96 Mcal/kg ME. Ruminal fermentation was measured from rumen fluid samples collected at the end of a 25 day period, while blood samples were collected at the beginning and end of this period. The digestibility and nitrogen balance were measured concomitantly, through total collection of feces and urine, respectively (3 consecutive days). Exp. 2 (performance): Forty-two bulls Nellore (initial body weight of 353 ± 13 kg and 24 months) were used in individual pens. The experimental design was a randomized blocks (blocked by initial BW) with the same treatments and diet as on metabolism design. The data were analyzed using the MIXED procedure of SAS. The differences between means were compared by the t-test with 5% probability and trends were discussed between 5 and 10% probability. The concentration of propionate was 8.72% greater for animals receiving Amylase (P = 0.027), showing decreasing trends in acetate concentration and consequently acetate: propionate ratio (P = 0.088). Plasma insulin concentration in animals receiving Amylase tended to be lower (P = 0.062). The digestibility of CP tended to be higher (P = 0.064), as well as for the digestibility of NDF in animals receiving Amylase (P = 0.066). The balance of nitrogen compounds was not affected using Amylase (P = 0.904). Among the performance characteristics, the final BW, hot carcass weight (HCW) and gains in BW and carcass weight tended to be greater for animals receiving Amylase (P = 0.092), which would correspond to almost 9 kg more carcass weight compared to control animals. For the meat quality characteristics, there were differences for the color L * (luminosity) (P = 0.041) and tendencies for the color b * (yellow) (P = 0.074). The color L * (37.80 vs 40.01) and b * (13.98 vs. 15.33) had lower values in animals receiving Amylase, compared to control, respectively. The content of hypocholesterolemic fatty acids was greater for Amilase (P = 0.049), corresponding to 5.92% higher in compared to the control group. The use of Aspergillus oryzae contanning alpha - amylase extract increases dietary utilization through better digestibility of CP and fiber, as well as greater concentration of propionate in the rumen which will imply in better performance both by gain in weight and by the characteristics of meat quality. (AU)

• FAPESP's process: 15/07046-1 - Use of Aspergillus oryzae alpha amylase in feedlot diets for Nellore
• Grantee: Cleisy Ferreira Do Nascimento
• Support Opportunities: Scholarships in Brazil - Doctorate