Effects Of Chlorogenic Acid On Growth Performance,Gastrointestinal Tract Histomorphology And Microbiota Of Hu Sheep

The purpose of this study was to investigate the effects of different levels of chlorogenic acid on the growth performance,serum biochemical indexes,antioxidant capacity,gastrointestinal tract tissue morphology and microbiota of Hu sheep.Ninety 2 months old healthy weaned lambs with similar body weight were randomly divided into 5 groups,with 3 replicates in each group and 6 in each replicate.The control group was fed the basal diet(CON group),while the test group 1(CGA1group),test group 2(CGA2 group),test group 3(CGA3 group)and test group 4(CGA4group)were respectively fed the basal diet + 500 mg/kg chlorogenic acid,basal diet +1000 mg/kg chlorogenic acid,basal diet + 2000 mg/kg chlorogenic acid and basal diet+ 3000 mg/kg chlorogenic acid,The Preliminary feeding period was 7 days and the formal period was 43 days.The results of the experiment were as follows:To study the effects of chlorogenic acid addition to diets on growth performance,apparent nutrient digestibility,serum biochemical indexes,antioxidant properties and meat quality of Hu sheep.The results of this experiment showed that: the average daily weight gain of Hu sheep in CGA3 group was significantly higher than that of CON group and CGA4 group(P<0.05),and the feed-to-gain ratio of CGA3 group was significantly lower than that of other groups;The final weight of Hu sheep in CGA2 and CGA3 groups were improved compared with that of CON group,but the difference was not significant(P>0.05).The apparent digestibility of crude fat was significantly higher than that of the CON and CGA4 groups(P<0.05),and the highest apparent digestibility of crude fat was found in the CGA3 group of Hu sheep in each group;The apparent digestibility of dry matter,crude protein,neutral detergent fiber,and acid detergent fiber in each treatment group did not differ significantly(P>0.05).The urea nitrogen content of Hu sheep in the CGA3 group was significantly higher than that of other groups(P<0.05),and the total cholesterol content was significantly lower than that of other groups(P<0.05);Compared with the CON group,the alkaline phosphatase activities of CGA2,3 and 4 groups were increased(P<0.05),and the alkaline phosphatase activity of CGA4 group was the highest;the β-hydroxybutyric acid content of each group with chlorogenic acid added tended to increase gradually compared with that of the CON group,but the difference was not significant(P>0.05).Compared with the CON group,the SOD activities of the CGA2 and CGA3 groups were significantly higher(P<0.05);The MDA activities of all experimental groups with chlorogenic acid were significantly lower than that of the CON group(P<0.05),and the MDA activity of the CGA2 group was the lowest.The shear force of the CGA1,CGA2 and CGA3 groups was significantly lower than that of the CON and CGA4 groups(P<0.05),with the lowest shear force in the CGA3 group;The drip loss and cooking loss of each group with added chlorogenic acid tended to be lower compared to the CON group,but the difference was not significant(P>0.05).The effects of chlorogenic acid addition to the diet on rumen tissue morphology,rumen fermentation parameters and rumen microbiota of Hu sheep were investigated.Compared with the CON group,the rumen papilla height of Hu sheep in the CGA1 and CGA4 groups was significantly lower(P<0.05),and the papilla height in the CGA2 and CGA3 groups tended to increase,but the difference was not significant(P>0.05).Compared with the CON group,the papilla width was significantly increased in the CGA1 and CGA2 groups(P<0.05).There was no significant effect of chlorogenic acid on the p H and NH3-N concentration of rumen fluid of Hu sheep in each test group(P>0.05).Acetic acid and propionic acid contents in CGA3 and 4 groups were significantly higher than those in CON,CGA1 and CGA2 groups(P<0.05);Ruminal isovaleric acid concentration in CGA3 group was significantly higher than those in CON,CGA2 and CGA4 groups(P< 0.05).Alpha diversity,compared with the CON and CGA1 groups,the Shannon index of the CGA3 and 4 groups was significantly higher(P<0.05);The rumen Simpson index of each group with chlorogenic acid was significantly lower than that of the CON group(P<0.05).The Chao index was significantly higher in all groups with chlorogenic acid than that of the CON group(P<0.05).In terms of Beta diversity,the similarity of samples within each test group was high,and the composition of samples in the CON group and the group with chlorogenic acid added were significantly separated,and the differences in the composition of microorganisms were relatively large.In terms of species composition of microorganisms,at the phylum level,the dominant species in all groups in this experiment were Firmicutes and Bacteroidota;Compared with the CON group,the addition of chlorogenic acid increased the relative abundance of Firmicutes and Bacteroidota in the Hu sheep and decreased the abundance of Actinobacteria in each group.At the genus level,the top three groups were Christensenellaceae_R-7_group,Olsenella and Prevotella in all groups.Whose Christensenellaceae_R-7_group and Prevotella relative abundance was higher with chlorogenic acid addition than in the CON group,with the highest relative abundance in the CGA1 group.In the correlation analysis between volatile fatty acid and genus level of the group,acetic acid and Christensenellaceae_R-7_group showed a very strong positive correlation,and total volatile fatty acid and Christensenellaceae_R-7_group showed a strong positive correlation.The effects of chlorogenic acid addition to the diet on the intestinal histomorphology and ileal microbiota of Hu sheep were studied.In the duodenum,the chorionic villus height and chorionic crypt ratio were significantly higher in the CGA3 group compared with the CON group(P<0.05),In the jejunum,the chorionic crypt ratio was significantly higher and the crypt depth was significantly lower in the CGA2 and3 groups compared with the CON group(P<0.05).In the ileum,the addition of chlorogenic acid significantly increased the ileal chorion height of Hu sheep(P<0.05),and increased the chorionic crypt ratio in the CGA2,3 and 4 groups(P<0.05);In terms of Alpha diversity,the addition of chlorogenic acid significantly increased the ileal microbial Chao index(P<0.05),with the highest Chao index in the CGA3 group;Compared with the CON group,the Shannon index of the CGA3 and CGA4 groups increased significantly(P<0.05),and the Simpson index decreased significantly(P<0.05);In terms of Beta diversity analysis,the composition of ileal samples was similar between the CGA1 and CGA2 groups;The composition of samples from the CON and chlorogenic acid-added groups was significantly different.In terms of microbial species composition,at the phylum level,the dominant species in all groups were Firmicutes and Actinobacteriota;Compared with the CON group,the addition of chlorogenic acid increased the relative abundance of Firmicutes and decreased the relative abundance of Actinobacteriota in the ileum of lambs.At the genus level,the top three groups in relative abundance were Aeriscardovia,Olsenella and Lachnospiraceae_NK3A20_group;Chlorogenic acid significantly increased the relative abundance of Aeriscardovia and Christensenellaceae_R-7_group(P<0.05),and decreased the relative abundance of Olsenella and norank_f__Eubacterium_coprostanoligenes_group(P<0.05).According to the review,the addition of chlorogenic acid to the diet of Hu sheep can significantly improve the growth performance of Hu sheep,regulate lipid metabolism,improve antioxidant capacity,promote the development of the rumen and intestinal tract,optimize the composition of the gastrointestinal flora,improve the meat quality of Hu sheep and enhance disease resistance.The recommended concentration of chlorogenic acid is 2000 mg/kg.