Effect of Dietary Rumen-Degradable Starch to Rumen-Degradable Protein Ratio on In Vitro Rumen Fermentation Characteristics and Microbial Protein Synthesis
Panliang Chen,
Yan Li,
Yizhao Shen,
Yufeng Cao,
Qiufeng Li,
Meimei Wang,
Mingchao Liu,
Zhiyuan Wang,
Zihan Huo,
Shuai Ren,
Yanxia Gao,
Jianguo Li
Affiliations
Panliang Chen
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Yan Li
Key Laboratory of Healthy Breeding in Dairy Cattle (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Hebei Agricultural University, Baoding 071001, China
Yizhao Shen
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Yufeng Cao
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Qiufeng Li
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Meimei Wang
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Mingchao Liu
Key Laboratory of Healthy Breeding in Dairy Cattle (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Hebei Agricultural University, Baoding 071001, China
Zhiyuan Wang
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Zihan Huo
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Shuai Ren
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Yanxia Gao
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
Jianguo Li
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China
The objective of this study was to investigate the effects of dietary rumen-degradable starch (RDS, g/kg of DM) to rumen-degradable protein (RDP, g/kg of DM) ratios (SPR) on in vitro rumen fermentation characteristics and microbial protein synthesis (MCPS). Treatments were eight diets with SPR of 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 and 2.6 and were formulated to be isoenergetic, isonitrogenous, and isostarch. Substrates were anaerobically incubated in sealed culture vials (100 mL) for 6, 24 or 48 h. Three incubation runs were conducted within two consecutive weeks. With the increase of the dietary SPR, the gas production (GP), in vitro dry matter disappearance (IVDMD) and concentration of MCPS and total volatile fatty acids (TVFA) linearly increased after 6 h of incubation (p ≤ 0.01), whereas they quadratically increased and peaked at the SPR of 2.3 after 24 and 48 h of incubation (p p 3-N) concentration linearly decreased (p < 0.01) after 6, 24 and 48 h of incubation. Based on the presented results, an SPR of 2.3 is recommended for formulating a diet due to its greatest IVDMD, IVNDFD, GP, TVFA and MCPS. However, as the results obtained are strictly dependent on the in vitro conditions, further in vivo studies are needed to verify our findings.
