| China is a large pork consuming country,and the per capita pork consumption accounts for the highest in the world.However,in the process of pig breeding,weaning stress of piglets often causes various weaning syndromes,which seriously affects the growth and development of piglets.It is understood that yeast hydrolysate(Yeast Hydrolysate,YH)contains more than 44.5% crude protein,which has the effect of improving animal growth performance and enhancing the immunity of the body.Yeast Cell Wall(YCW),on the other hand,has the effect of improving non-specific immunity and promoting the proliferation of beneficial intestinal bacteria in the body.The purpose of this experiment was to study the effect of adding two yeast derivatives(yeast hydrolysate and yeast cell wall)to the diet on the growth and development of piglets and their mechanism.In the yeast hydrolysate test,96 piglets weaned at 25±3d were randomly divided into 4 experimental groups: group A(basal diet,control group),group B(basal diet +4% hydrolysate),group C(basal diet + 2% plasma protein powder + 2% hydrolysate)and group D(basal diet + 4% plasma protein powder),with 6 replicates of 4 pigs in each group.Growth performance data were recorded daily;blood samples were collected on the 14 th day of the test to determine immune-related indexes;piglets in each group were randomly selected for intestinal sampling(ileum,jejunum and duodenum)and intestinal morphology was examined.The results showed that the daily feed intake and daily weight gain of piglets in group D were significantly higher than those in the control group(P<0.05),and the feed coefficient was significantly lower than that in group A.There were no significant differences between groups B and C and group D(P>0.05);compared with group A,there were significant differences in serum alkaline phosphatase,glutamic oxalacetic transaminase and immunoglobulin G in groups B,C and D(P<0.05).And there was no significant difference between groups B and C and group D.In terms of jejunal and ileal development,experimental group D had better intestinal villus height,V/C compared to all other groups(P < 0.05),and group A had poorer intestinal development compared to other groups,and the results of growth performance and immune performance tended to be consistent.Yeast cell wall test animals were selected from 72 Du x Chang x Da ternary crossbred weaned piglets with similar weight and good body condition at 28 days of age,and divided into 6 treatment groups(control group,yeast cell wall Ⅰ,yeast cell wallⅡ,cell wall Ⅲ,cell wall Ⅳ,cell wall Ⅴ)according to the principle of similar average weight and half of each male and female,with 6 replicates in each group.Growth data were recorded daily,blood samples were collected,and immune-related indexes were to be measured;at the end of the test,fresh piglet feces were collected from each group and brought back to the laboratory for E.coli and Lactobacillus counts in feces using the plate count method.Three groups(control,cell wall group III and cell wall group IV)were selected,and two piglets in each group were randomly selected to collect 10 g of fresh piglet feces,which were divided into sterile lyophilized tubes and immediately frozen and sent to sequencing company for fecal flora and metabolite detection.The results of the study showed that there was no significant difference(P>0.05)in the data related to growth performance between the groups.Compared to the control group,all groups had some effect in reducing diarrhea,with yeast cell wall IV being able to reduce the diarrhea rate of piglets very significantly(P < 0.05).Serum biochemical indexes showed that yeast cell wall III significantly increased the levels of glutamic transaminase activity and globulin content in piglets’ serum.Yeast cell wall IV and V significantly increased the number of lactic acid bacteria in the feces(P<0.05),while yeast cell wall III and IV significantly decreased the number of E.coli in the feces(P<0.05).In the fecal flora zone analysis,there was an increasing trend in sobs,ace and chao indices in cell wall group III and cell wall group IV compared with the control group.There was an increase in OUT unique to the piglet fecal-like flora compartment.In the metabolite analysis,we found that the addition of yeast cell wall to the diet of weaned piglets produced six differential metabolites of lysophospholipids,choline,guanine nucleoside,γ-tocotrienol,buddleia methyl ester and inosine,all of which were up-regulated compared to the control group and were mainly involved in the metabolism of glycerophospholipids,amino acids and nucleotides.In conclusion,the addition of yeast hydrolysate(4% yeast hydrolysate,2% yeast hydrolysate + 2% plasma protein powder)to the diet was used to replace plasma protein powder,which could replace plasma protein powder to some extent by adding it to the weaned piglet feed without affecting the productive performance of the weaned piglets,while having similar effects to plasma protein powder in terms of immunity.Among the different yeast cell wall products,yeast cell wall IV performed the best,significantly reducing the frequency of diarrhea in weaned piglets,increasing the content of Lactobacillus and reducing the number of E.coli in piglet feces.This may be due to the fact that the addition of yeast cell wall increases the abundance and diversity of the flora and promotes the stability of the intestinal microecological balance,which in turn maintains the health of the gastrointestinal tract. |
