Abstract:

The objective of this experiment was to analyze the effects of different perilla （Perilla frutescens） materials on rumen fermentation parameters， serum biochemical parameters and rumen bacteria flora of Guizhou black goat （Capra hircus） cull ewes， in order to provide technical support for developing perilla and its by-products into feed materials for use in the fattening of cull ewes. Guizhou black goats （n=32） with similar age and body condition were randomly divided into one control group and three treatment groups， which were fed with different total mixed ration pelleted feeds. The four groups comprised a control group （CK group）， a perilla straw group （S₁ group）， a perilla meal group （S₂ group） and a perilla seed group （S₃ group）. The experiment lasted for 74 days， including a 14-day adjustment period and a 60-day experimental period. Body weight was measured every 30 days. At the end of the experiment， blood and rumen fluid were collected for determination of serum antioxidant enzyme activity， rumen fermentation parameters and rumen microflora composition. The results showed that adding different perilla materials could significantly increase the daily gain of cull ewes in the early fattening period （0-30 days， P<0.05）， with S₃ group having the highest weight gain， followed by S₂ and S₁ groups； while there was no significant difference in daily gain among all groups in the late fattening period （30-60 days， P>0.05）. Secondly， the activities of superoxide dismutase and glutathione peroxidase and the concentration of malondialdehyde in serum were significantly increased in S₁ and S₃ groups（P<0.05）， while the activities of catalase and the concentration of total antioxidant capacity were varied between groups （P>0.05）. The contents of acetic acid were significantly reduced in all treatment groups （P<0.05）， but there was no significant difference （P>0.05） between S₂ or S₃ and CK in the levels of propionic acid， butyric acid， isobutyric acid， valeric acid and isovaleric acid. However， the fatty acid content in the S₁ group was significantly lower than in the CK group （P<0.05）. In addition， no significant difference in the content of ammonia nitrogen was detected among the groups. High-throughput sequencing analysis of rumen microflora showed no significant difference in rumen microbial species for the Shannon index （P>0.05）. However， the abundance of some bacteria differed significantly between S₁ and S₃ groups for the Chao 1 index （P<0.05）. The highest OTU number was detected in the S₁ group， followed by S₂， CK and S₃ groups， in that order. The dominant flora of each sheep group was analyzed at phylum level. They were mainly Firmicutes， Bacteroidetes and Proteobacteria. The total abundance of Firmicutes and Bacteroidetes in groups S₂ and S₃ was slightly higher than that in the CK group （P>0.05）， while that in S₁ was lower than CK （P>0.05）. Interestingly， the abundance of Proteobacteria in all three groups， S₁， S₂ and S₃ was lower than in CK. Cluster analysis was performed at genus level. The dominant flora were mainly Prevotella， Quinella， Succinivibrio， and an uncultured rumen bacterium. The abundance of the unidentified rumen bacterium was significantly higher in S₁， S₂ and S₃ than in CK （P<0.05）， while the abundance of other microorganisms differed in each group， but no significant overall pattern was detected （P>0.05）. In summary， adding different perilla components improved the bodyweight gain of cull ewes to different degrees in the first 30 days of feeding， with perilla seeds having the best effect. Feeding perilla materials also increased the serum antioxidant activity， regulated the digestion ability of crude fiber and non-fiber carbohydrate and regulated the composition and abundance of rumen microflora， which may account for the initial improvement in weight gain of Guizhou black goat cull ewes， observed in this experiment.

Key words: perilla materials, black goat, cull ewes, rumen fermentation, serum antioxidant activity, rumen microflora