In vitro Study on Effects of Different Proportions of Hops Pellets and Cerium Chloride and Its Combination on Rumen Fermentation
The purpose of this experiment was to investigate the effects of different proportions of hops pellets and cerium chloride and its combination on rumen fermentation through a in vitro study. The total mixed ration ( TMR) and rumen fluid of high⁃yield dairy cows were used as fermentation substrate and fermentation micro⁃flora. A 4×4 two⁃factor experiment design was adopted, the hops pellets were set 4 concentrations of blank ( 0 mg／L) , low ( L, 3.34 mg／L) , middle ( M, 6.67 mg／L) and high ( H, 10.00 mg／L) , respectively; the cerium chloride were set 4 concentrations of blank ( 0 mg／L ) , low ( l, 1.33 mg／L ) , middle ( m, 1.60 mg／L) and high ( h, 1.87 mg／L) , respectively, to meet the hops pellets contents of dry matter fermen⁃tation substrate were 0, 0.5, 1.0 and 1.5 g／kg, respectively; and the cerium chloride contents were 0, 0.20, 0.24 and 0.28 g／kg, respectively. According to different combinations of hops pellets and cerium chloride, 16 groups (5 replicates per group) were divided into C ( blank control) , l, m, h, L, Ll, Lm, Lh, M, Ml, Mm, Mh ,H, Hl, Hm and Hh. Anaerobic fermentation was carried out for 24 h using the American ANKOM RFS gas measurement system, and the pH, ammonia nitrogen ( NH3⁃N) concentration, microbial crude pro⁃tein ( MCP) yield, dry matter digestibility ( DMD) , gas production ( GP) and the concentrations of acetic acid, propionic acid and total volatile fat acids ( TVFA) were detected when fermentation stopped. The results showed as follows: 1) among the groups adding hops pellets alone, the NH3⁃N concentration in groups L and M were significantly decreased than that in group C ( P＜0.05) , the MCP yield in group M was significantly increased than that in group C ( P＜0.05). 2) Among the groups adding cerium chloride alone, the MCP yield in groups l, m and h was significantly increased than that in group C ( P＜0.05 or P＜0.01), the DMD, GP and concentrations of acetic acid, propionic acid and TVFA in group l were significantly increased than those in group C ( P＜0.05). 3) The combination of hops pellets and cerium chloride had significant interactive effects on the NH3⁃N, acetic acid, propionic acid and TVFA concentrations and MCP yield ( P＜0.05). The NH3⁃N concentration in all groups except groups Hh and Lh was significantly decreased that in group C ( P＜0.01) , and that in groups Hl and Ll was lower; the MCP yield in all groups except group Lh was significantly in⁃creased that in group C ( P＜0.05 or ( P＜0.01) , and that in groups Lm, Ll, Ml was higher; and the TVFA concentration in groups Mh, Lh and Ll was significantly increased that in group C ( P＜0.05). According to the comprehensive analysis of each index, groups M, l and Ll are the optimal group among hops pellets and ceri⁃um chloride alone and its combination groups, the rumen fermentation performance effect can be improved in the order of group Ll＞ group l＞ group M.[ Chinese Journal of Animal Nutrition, 2019, 31(9) :4200⁃4207]
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维普
