Abstract: The aim of this experiment was to study the effect of rutin addition to the diet on rumen fermentation, rumen flora structure and antioxidant properties in perinatal Hu sheep. Thirty 24-month-old perinatal Hu sheep with similar perinatal period and similar body weight[(62.90±2.80) kg] were selected and randomly divided into three groups with 10 replicates in each group. The rutin additive dose was 0 mg·kg^-1 BW (Control group), 50 mg·kg^-1 BW (Group Ⅰ) and 100 mg·kg^-1 BW (Group II) to the basal diet, respectively. The pre-test period was 7 d and the formal test period was 56 d. At 28 days postpartum before morning feeding, five sheep in each group were randomly selected for slaughter, and rumen tissue morphology, rumen fermentation parameters, antioxidant properties and rumen flora structure were examined. The results showed that:1) The differences in daily roughage intake, daily dry matter intake and daily neutral detergent fiber intake of perinatal Hu sheep were not significant (P>0.05) among the groups; Postpartum body weight, FBW and ADG were higher in the 2 experimental groups of perinatal Hu sheep than in the Control group, but the differences were not significant (P>0.05), there was no significant change in the number of lambing and the weight of lambs in each group (P>0.05); 2) The rumen papilla length of perinatal Hu sheep in Group II was significantly increased compared with that in Control group (P<0.05); 3) GSH-Px and CAT activities in rumen fluid of Group I were significantly higher than those in Control group (P<0.05); 4) Compared with the Control Group, the concentration of bacterial protein, protozoan protein, acetic acid, propionic acid, valeric acid and total volatile fatty acids (TVFA) in the rumen fluid of perinatal Hu sheep in Group II were significantly higher (P<0.05), and the concentration of microbial protein was extremely significantly higher (P<0.01); 5) The first dominant bacterial phylum in the rumen of perinatal Hu sheep in the Control group and Group I was the Frimicutes, and the second dominant bacterial phylum was the Bacteroidetes; The first dominant bacterial phylum in the Group II was the Bacteroidetes, and the second bacterial dominant phylum was the Frimicutes. Compared with the Control group, the relative abundance of both the Frimicutes and the Spirochaetes were significantly lower in Group II (P<0.05), and the relative abundance of the Bacteroidetes was significantly higher in Group II (P<0.05). The dominant genus of rumen bacteria in all groups of perinatal Hu sheep was Prevotella. Compared with the Control group, the relative abundance of Prevotella was significantly higher in Group I (P<0.05); The relative abundance of Prevotella was highly significantly higher in Group II (P<0.01), and the relative abundance of Treponema was significantly lower in Group II (P<0.05). In summary, rutin has improved the morphology of rumen tissue in perinatal Hu sheep, and can improve the antioxidant capacity of rumen, change the structure of rumen flora, and effectively improve the fermentation function of rumen in perinatal Hu sheep.

Key words: rutin, perinatal Hu sheep, rumen tissue, antioxidant performance, rumen fermentation, rumen flora structure