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The effects of adding exogenous amylases, a protease and their combinations on in vitro dry matter and starch digestibility of mature dent corn grain.

F. X. Amaro

Events

06-23-2020

Abstract:

185
The effects of adding exogenous amylases, a protease and their combinations on in vitro dry matter and starch digestibility of mature dent corn grain.
F. X. Amaro*1, K. G. Arriola1, D. Kim1, M. C. N. Agarussi1,2, V. P. Silva1,2, A. P. Cervantes1, Y. Jiang1, L. F. Ferraretto1, S. Yu3, W. Li4, A. T. Adesogan1, D. Vyas1. 1University of Florida Gainesville, FL, 2Universidade Federal de Vicosa Vicosa, MG, Brazil, 3DuPont Nutrition & Biosciences Aarhus, Denmark, 4DuPont Nutrition & Biosciences Wilmington, DE.

The objective was to evaluate 4 amylases, a protease and their combinations on ruminal in vitro dry matter (IVDMD) and starch digestibility (IVSD) of mature dent corn grain using a batch culture system. Treatments were control (no enzyme), 4 amylases (4Cs4, 5Trga, 6Afuga, 7Fvga; 0.25 mg/g DM each), a protease (11P14L) and their respective combinations. Experimental design was a randomized complete block and treatments were arranged in a 2 � 5 factorial design with 2 levels of 11P14L (0, 0.25 mg/g DM) and 5 levels of amylase (0 or 0.25 mg/g DM each of 4Cs4, 5Trga, 6Afuga, and 7Fvga) resulting in 10 treatments incubated for several time points (0, 3, 7, 9, 12, and 24 h) in quadruplicates in 3 independent runs (blocks). Mature ground (4-mm) dent corn grain was used as substrate (0.5 g) and enzymes were directly applied on the substrate before incubating in pooled rumen fluid collected from 3 rumen-cannulated lactating dairy cows. Data were analyzed using GLIMMIX procedure of SAS to test for main effects of amylase, protease and the interaction. Block (run) was used as random factor. Synergistic effects of individual amylase � protease within each time point were tested through contrasts (4Cs4 vs 4Cs4 � 11P14L; 5Trga vs 5Trga � 11P14L; 6Afuga vs 6Afuga � 11P14L; 7Fvga vs 7Fvga � 11P14L). Main effects of amylase and protease on IVDMD were observed at all time points (P < 0.01). Synergistic improvements in IVDMD were observed with every combination of amylase and protease after 3, 7, 9, 12, and 24h of incubation (P < 0.05). Based on the contrast values, synergistic improvement in IVSD was observed with the combination of 5Trga � 11P14L and 6Afuga � 11P14L at 3, 7 and 12 h of incubation (P < 0.05). Similarly, the combination of 4Cs4 � 11P14L and 7Fvga � 11P14L resulted in IVSD improvement at 12 and 3 h of incubation, respectively (P < 0.05). In conclusion, IVDMD and IVSD were increased by exogenous enzymes with greater improvements observed with the combination of amylases and protease. Future in vivo studies are required to validate these findings and recommend these enzymes for inclusion in livestock feed.

Keywords: starch, amylase, protease.

Biography: Felipe Xavier Amaro was born in Brazil, got his bachelor's degree in animal sciences from Universidade Federal de Vicosa in 2016. He joined the student body of the University of Florida in 2017 and got his master's degree in 2018, since then he has been working on his Ph.D. researching nutritional strategies to improve feed efficiency in dairy cattle.