| The aim of this study was to evaluate the effects of yeast culture（YC）supplementation on digestive tract microecology,enzyme activity and fattening performance in sheep,and evaluate the availability of YC supplementation in fattening sheep production.20 castrated male small-tailed Han sheep were randomly divided into two groups according to the principle of uniform weight,with 10 replicates in each group and one sheep per replicate.The sheep in control group were fed on a fully mixed granular basic diet,and the sheep in treatment group were fed on basic diet supplemented with 2.3 g/kg（DM）of YC.The trial period consist of 15 days to adaption and 60 days of feeding.The results of this study showed that:1.Supplemented with YC in the diet significantly reduced the ruminal pH（P < 0.05）,and increased the ratio of acetic to propionic acid（P < 0.05）.There is a tendency to decrease the ammonia nitrogen（NH3-N）with YC supplementation（P = 0.08）,while a tendency to increase the concentrations of acetic acid（P = 0.06）and TVFA（P = 0.08）.2.In this study,YC supplementation in the diet significantly affected the ruminal and lower-jejunum microflora.Supplemental YC significantly increased the relative abundances of Prevotella1,Succinivibrio,and Bifidobacterium（P < 0.05）,whereas,decreased the ralative abundances of Prevotella7,Roseburia,Succiniclasticum and Oribacterium（P < 0.05）.In lower-jejunum,supplemental YC significantly increased the relative abundances of Turicibacter 、 CandidatusSaccharimonas 、 LachnospiraceaeNK3A20 、 CandidatusSaccharibacteria、Saccharofermentans and Bifidobacterium（P < 0.01）.The relative abundances of Peptoclostridium 、 [Eubacterium]nodatum 、 Pseudoramibacter and RuminococcaceaeUCG005 were significantly decreased（P < 0.05）with YC supplementation.3.Compared with control group,the activities of trypsin and lipase in rumen,duodenum and lower-jejunum were significantly increased（P < 0.05）with YC supplementation.There is a tendency to increase the amylase activity in duodenum with YC supplementation（P = 0.07）.Supplemental YC significantly increased the lipase activity in rumen and lower-jejunum（P < 0.05）and had the tendency to increase the lipase activity in the duodenum（P = 0.08）.However,supplemental YC significantly decreased the cellulase activity in the lower-jejunum（P < 0.05）.4.Supplemented with YC had a tendency to increase ADG（20g/d;P = 0.06）.However,there was no significant effect on DMI,F/G and GR with YC supplementation.In conclusion,YC can modify rumen fermentation,improve the digestive enzyme activity.Moreover,supplemental YC can regulate the BCC of rumen and lower-jejunum,which improves the digestion and utilization of nutrients,maintains the health of the intestines,and improve the fattening performance. |
