Effects of vitamin A,D and E supplementation during pregnancy on rumen fermentation parameters and microflora of grazing sheep

ZHANG Zhipeng; FU Chenfei; ZHANG Jianqiang; MA Junde; ZHANG Wenju

doi:10.13557/j.cnki.issn1002-2813.2025.18.003

Abstract：The experiment aimed to investigate the effects of supplementing different gradient levels of vitamins A,D and E in the supplementary feed during pregnancy on the rumen fermentation characteristics and microflora of grazing sheep.A total of 40 Chinese Merino sheep with a similar age and weight of(55.38±7.26)kg in late pregnancy were selected and randomly divided into four groups,with 10 replicates per group and one sheep per replicate.Under grazing conditions,the control group(group CON)was only fed with concentrated feed.The low-dose group(group L)supplemented 900,100 and 30 IU/kg of vitamins A,D,and E in the concentrated feed,respectively.The medium-dose group(group M)supplemented 1 800,200 and 60 IU/kg of vitamins A,D,and E in the concentrated feed,respectively.The high-dose group(group H)supplemented 2 700,300 and 90 IU/kg of vitamins A,D,and E in the concentrated feed,respectively.The pre-test period was five days,and the formal test period was 55 days.The results showed that compared with the group CON,the concentrations of acetic acid,propionic acid and total volatile fatty acids in the group M were significantly increased(P＜0.05),the ethylene-propylene ratio in the group CON was significantly higher than that in groups L,M and H(P＜0.05).There were no significant differences in ruminal pH value,ammonia nitrogen and butyric acid concentrations between each group(P＞0.05).Ace index and Chaol index in the group M were significantly higher than those in the group CON(P＜0.05),Shannon index was significantly higher than that in the groups CON and L(P＜0.05).β diversity analysis showed that the groups CON and M samples were significantly separated in principal coordinate analysis(PCoA)(P＜0.05).At the phylum level,Bacteroidota and Firmicutes were the dominant flora,at the genus level,Prevotella and Cryptobacteroides were the dominant bacterial genera.The study indicates that adding vitamins A,D and E to supplementary concentrated feed can enhance the energy utilization efficiency,improve the richness,diversity and abundance of rumen microorganisms of grazing sheep,and the effects are better when 1 800,200 and 60 IU/kg of vitamins A,D and E are respectively supplemented in the feed.