Effects Of Dietary Supplementation With Clostridium Butyricum On Growth Performance,Carcass Traits And Immune Function Of Fattening Goats

In animal production,it is of great importance to improve feed efficiency and organism health for efficient breeding and quality production.A nutritional control strategy can be continuously optimized to accelerate feed conversion for animal growth and contribute to the alleviation of adverse reactions due to immunosuppression.Clostridium butyricum,as a probiotic that can adapt to the gastrointestinal environment,has an independent digestive enzyme system and can secrete a variety of bioactive substances beneficial to humans and animals,helping to improve the function of the intestinal barrier,promote the digestion and absorption of feed and other nutrients,improve feed efficiency,and effectively improve the health of the body.Currently,studies have shown that supplementing C.butyricum in the diets of monogastric animals can improve the integrity of the intestinal tract,inhibit the invasion of harmful bacteria,enhance the immune function of the intestine,promote the digestion and absorption of nutrients,and alleviate inflammatory reactions.However,the effects of C.butyricum in ruminants are still unclear,especially the effects of C.butyricum rumen digestive system on the flora are still unclear.Therefore,in order to clarify the effects of C.butyricum in the rumen and intestinal tract of ruminants,this study aimed to investigate the effects of C.butyricum supplementation in the diet on the growth performance,carcass traits and immune function of fattening goats.Trial 1:Effects of dietary supplementation with C.butyricum on growth performance,apparent digestibility,blood metabolites,ruminal fermentation and bacterial communities of fattening goatsTwenty-four healthy male Albas goats(body weight=22±2.03 kg)were randomly divided into 3 treatment groups with eight goats in each group.The treatments were as follows:control group(CON)(basal diet,concentrate to forage ratio=65:35;n=10);low-dose C.butyricum(LCB)(basal diet plus 2.0×10~8 CFU/kg C.butyricum;n=8);and high-dose C.butyricum(HCB)(basal diet plus 1.0×10~9 CFU/kg C.butyricum;n=8).The total trial period was 70 days.To evaluate the effects of dietary supplementation with different levels of C.butyricum on growth performance,plasma biochemistry,nutrient digestibility,rumen fermentation,rumen and rectal bacterial communities of fattening goats.The results showed that supplementing high concentration diets with C.butyricum helped delay the decline of rumen p H,but had no significant effect on growth performance(P>0.10).Compared with the control group,dietary C.butyricum supplementation significantly increased the relative abundance of Prevotella＿1,Christensenellaceae AE＿R-7＿Group and Prevotellaceae AE＿UCG-003(P<0.05),and significantly decreased Succiniclasticum and Muribaculaceae＿unclassified(P<0.05).The relative abundance of Clostridium in the rumen was less than 1.0%.Moreover,16S r DNA analysis showed that the rectal Clostridium count was significantly decreased(P<0.05),and the relative abundance of Alistipes and Akkermansia had a significant upward trend(P<0.10)compared with the control group.Summary,Supplementing C.butyricum in a high-concentrate diet did not significantly affect the performance of fattening goats,while regulation of the gastrointestinal microbiota was associated with rumen fermentation.Trial 2:Effects of dietary supplementation with C.butyricum on carcass traits of fattening goats and chevon qualityThe design and feeding management of the current trial were the same as the trial 1.Based on the growth trial,10 goats were randomly selected for slaughter from the CON and HCB(CB)groups,and the live weight,hot carcass weight and visceral weight were recorded,and the longest dorsal muscle of fattening goats and cecum contents to evaluate the effects of C.butyricum on the carcass traits,quality and antioxidant capacity of chevon through the regulation of intestinal microbiota.The results showed that dietary supplementation with C.butyricum had no significant effect on carcass traits,organ index,cooking loss and shearing force of fattening goats(P>0.10).There was no significant change in drip loss of chevon in each treatment over 24 h,while drip loss in the CB group was significantly lower than that in the CON and RPCB groups over 48 h(P<0.05).This was consistent with the result of lower p H of chevon in the CB group(P<0.05),indicating that supplementation of C.butyricum in the diet of goats helped to improve the water retention capacity of chevon.In addition,C.butyricum could effectively improve the redness(a*)and total antioxidant capacity(T-AOC)of chevon,and led to an effective decrease in the malondialdehyde(MDA)content of chevon(P<0.05).It showed that dietary supplementation with C.butyricum had no significant effect on the carcass traits of fattening goats,but it could improve the quality and antioxidant capacity of chevon.In addition,the results at the genus level of 16S r DNA sequencing showed that the addition of C.butyricum to the diet significantly reduced the relative abundance of Clostridium and Clostridiaceae＿unclassified(P<0.05).Moreover,the Clostridium species level results showed that the presence of C.butyricum was detected only in the CB group,although its relative abundance was<0.1%,and the samples were detected with C.butyricum in both rumen and rectal samples.The correlation heat map showed that g＿and s＿Clostridiales＿unclassified performed a high positive correlation with p H and MDA(P<0.05),and C.butyricum showed a positive correlation with a*of chevon(P<0.05).The results showed that dietary supplementation of C.butyricum had no significant effect on the carcass traits of fattening goats,but C.butyricum could reach the intestine via the rumen,optimize the structure of the intestinal microbiota to improve the quality and antioxidant capacity of chevon.Trial 3:Effects of dietary supplementation with C.butyricum on LPS-induced acute immune stress in goatsThe strong immune function of fattening goats is also essential to improve their growth performance.It was hypothesized that C.butyricum could improve the immune function and antioxidant capacity of goats by regulating their intestinal microbiota and blood metabolism,and effectively alleviate the acute immune stress response induced by lipopolysaccharide(LPS).From the CON and LCB(CB)groups respectively on the basis of trial 1,four goats were randomly selected from each group for the LPS challenge on day 71,and blood and feces were collected at 0 and 6 h to evaluate the effects of C.butyricum on their intestinal microbiota,immune function,antioxidant function and plasma metabolites.The results showed that C.butyricum had no significant effect on plasma biochemical parameters at the beginning of the LPS challenge;however,supplementation with C.butyricum effectively increased plasma levels of Ig A,Ig G,T-SOD and T-AOC(P<0.05)and resulted in a significant decrease in plasma TNF-α,IL-6 and MDA levels(P<0.05)and an increasing trend in IL-10 levels(P<0.10).Rectal microbiota analysis showed that supplementation of goat diets with C.butyricum significantly increased the relative abundance of Epsilonbacteraeota at the phylum level;At the genus level,the relative abundance of Campylobacte and Anaerorhabdus]＿furcosa＿group also increased significantly(P<0.05),and the dominant group Christensenellaceae＿R7＿Group also showed a significant increase in its abundance values(0.05<P<0.10),while Clostridium and Lachnospiraceae＿UCG-001 showed a significant decrease in their abundance values(P<0.05).Spearman’s correlation analysis showed that the abundance of Clostridium and Lachnospiraceae＿UCG-001 decreased significantly(P<0.05).Lachnospiraceae＿UCG-001 relative abundance reduction was positively correlated with TNF-αand IL-6 and negatively correlated with T-SOD,while the correlation results of Anaerorhabdus]＿furcosa＿group with Clostridium and Lachnospiraceae＿UCG-001,Christensenellaceae＿R-7＿group and Ig A had a strong positive correlation(P<0.01).When the LPS challenge continued up to 6 h,C.butyricum still resulted in significantly higher plasma Ig A,IL-10and T-SOD concentrations in goats than in controls,effectively reducing TNF-αlevels(P<0.05).Meanwhile,plasma levels of total cholesterol and low-density lipoprotein were significantly decreased and plasma d-proline expression was significantly upregulated(P<0.05).In addition,correlation analysis showed that significant expression of plasma inflammatory and antioxidant factors was strongly correlated with the upregulation of d-proline(P<0.05).This suggested that dietary supplementation with C.butyricum could optimize the structure of the intestinal microbiota,synergistically improve the expression of plasma metabolites to enhance the alleviating effect of goats on acute immune stress response.To sum up,high-concentrate dietary supplementation with C.butyricum had no significant effects on growth performance and carcass traits of fattening goats,but helped improve chevon quality.There were significant differences in Clostridium abundance in the rumen and intestine of goats,and dietary supplementation with C.butyricum could reach the intestine via the rumen and optimize the microbiota structure,reducing the relative abundance of harmful Clostridium.Combined non-targeted metabolomics techniques showed that C.butyricum could effectively alleviate the acute immune stress induced by LPS in goats by regulating the expression of intestinal microbiota and blood metabolites,and improve the immunity and antioxidant capacity.