Effects of plant-derived fermented broth on rumen fermentation, gastrointestinal development, and microbial community in fattening lambs

Lu Zhang¹Huiwen Zhang²Lianjie Song³Yongliang Li¹Jianjun Guo³Feng Li³Bosen Li²Wei Chen²Yuqing Liu¹Haitong Yang¹Jianjie Li¹Xinsheng Sun^1*Yuhong Gao^1*

• ¹Hebei Agricultural University, Baoding, China
• ²Veterinary Drug Administration, Chengde City, China
• ³Chengde Academy of Agricultural and Forestry Sciences, Chengde, China

Digestive dysfunction in lamb fattening has been concerned in recent years. The objective of this study was to investigate the effects of a fermentation broth (FB) derived from 8 plants on rumen fermentation, gastrointestinal development, and microbial community in fattening lambs via in vitro and in vivo tests. In vitro rumen fermentation was performed with 6 groups of 0, 1:125, 1:250, 1:500, 1:1000, and 1:2000 (FB:diet, mL/g). Fermentation parameters and nutrient disappearance rates were determined during a period of 48 h. Based on results of in vitro test, two optimal doses of FB (1:500 and 1:1000) were selected for further in vivo test for 120 d. Total of 90 weaned small-tailed Han lambs were assigned into 3 groups. Each group was offered FB in drinking water at 0 (control), 1:500, and 1:1000 (vol/vol). Results showed that three parameters of gas production (GP) including fast-and slow-degradable fractions and theoretical GP were greater (P < 0.05) for both 1:500 and 1:1000 groups than other groups. Results from in vivo test exhibited that two FB supplements (1:500 and 1:1000) improved microstructure in rumen (apilla length, papilla surface, mucosa thickness, and muscle thickness) and in jejunum (villus height, villus surface, and muscle thickness). Moreover, two diversity indexes of rumen bacterial community in two FB groups, including PD_whole_tree (P = 0.06) and shannon (P = 0.07), demonstrated the increased trends compared to the control group. Rumen Firmicutes and Bacteroidota abundances were also increased (P < 0.01) and decreased (P < 0.01) by 1:500 FB, respectively. In jejunum, abundances of Euryarchaeota and Methanobrevibacter for 1:500 FB demonstrated the decreases (All P = 0.02), while Actinomycetes and Aeriscardovia abundances exhibited the increases (All P = 0.01), compared to the control. In summary, FB supplements in lambs' drinking water at a ratio of 1:500 (FB:diet, mL/g) could improve rumen fermentation and microecological balance.