Effects Of Different Probiotic Fermented Corn-Soybean Meal Feeds On Production Performance,Lipid Metabolism And Intestinal Health Of Laying Hens

During the peak egg laying period,laying hens have strong metabolism and reproductive function,relatively weak immunity and resistance,and easily affected intestinal absorption and barrier function.In addition,some feed ingredients contain anti-nutritional factors that will reduce feed quality,and mold and toxins can easily damage the liver.The impact of these unfavorable factors can affect the rate of fat deposition and the integrity of intestinal function,leading to problems such as fatty liver syndrome and intestinal inflammation.Fermented feed has the advantages of good palatability,rich in probiotics and various enzymes,and high digestion and absorption rate.Feeding probiotic fermented feed can regulate the lipid metabolism of laying hens,improve the intestinal morphology and barrier function of laying hens,and regulate intestinal bacteria.Flock structure,thereby improving production performance and egg quality,therefore,fermented feeds have received much attention in the poultry industry.A total of 360 healthy 22-wk-age Jingfen 6 laying hens were randomly divided into four treatments,including control group(CON),Clostridium butyricum group(CB),Lactobacillus curlicus group(LC)and Lactobacillus salivarius group(LS).The control group was fed with basic diet,and 6%fermented feed was used in CB group,LC group and LS group to replace the unfermented feed raw materials in basic diet.Each treatment had 6 replicates and 15 chickens per replicate.The trial period is 10 weeks,including 2 weeks of pre-trial period and 8 weeks of trial period.The experiment first measured the nutritional quality of the feed before and after fermentation,and then revealed the possible mechanism of the fermented feed regulating the lipid metabolism and intestinal health of laying hens by measuring the laying rate,feed conversion ratio,egg quality,serum and hepatic lipid content,small intestine morphology,intestinal barrier and other related indicators,combined with the data of microbiomics and transcriptome.The main results are as follows:(1)The pH value,crude fiber and ash content of fermented feed were significantly lower(P<0.05).Compared with unfermented feed,the contents of crude protein,moisture and crude fat in fermented feed did not change significantly(P>0.05).In fermented feed,The content of β-glucan decreased significantly(P<0.05),and phytic acid content tends to decrease(P=0.075).(2)Compared with the control group,the feed conversion ratio of laying hens was significantly decreased by adding Lactobacillus curlicus and Lactobacillus salivarius fermented feed in the basic diet(P<0.05),and the ADFI and egg laying rate had no significant difference among the treatments(P>0.05).Feeding Lactobacillus salivarius fermented diet significantly increased albumen height and Haugh unit(P<0.05),while the addition of fermented feed had no significant effect on egg shape index,eggshell thickness,eggshell strength and yolk color(P>0.05).(3)The addition of Lactobacillus salivarius fermented feed in the diet decreased the content of cholesterol in serum and liver(P<0.05)and increased the content of High density liptein cholesterol(P<0.05).Feeding different probiotic fermented feeds changed the gene expression in the liver of laying hens to varying degrees.Among them,the Lactobacillus salivarius group had the most significant difference genes,including 687 up-regulated genes and 733 down-regulated genes.These difference genes were significantly enriched in the biological processes related to lipid metabolism,including cholesterol biological metabolism,lipid biosynthesis,cholesterol homeostasis,steroid metabolism and so on.Lactobacillus salivarius fermented feed may inhibit lipid biosynthesis by down regulating SC5D,MSMO1,NSDHL,ACLY,LIPA and other genes,so as to regulate lipid metabolism in laying hens.(4)Feeding fermented feed could increase the villus height and the ratio of villus height to crypt depth(P<0.05),reduce the crypt depth(P<0.05),and improve the morphology of small intestine.The addition of fermented feed increased the content of sIgA in jejunum and enhanced the function of immune barrier.Compared with the control group,the expression of Occludin and Mucin-2 genes in jejunum were significantly up-regulated in the fermented feed group.Feeding fermented feed adjusted the cecal flora structure of laying hens,especially the flora richness of Lactobacillus salivarius group increased significantly,the relative abundance of beneficial bacteria increased and the relative abundance of harmful bacteria decreased.Some bacterial genera were significantly correlated with Haugh unit,cholesterol content in serum and liver,villus height and crypt depth of small intestine,intestinal barrier genes and sIgA content.Erysipelotrichaceae,Desulfovibrionace and Bifidobacterium were related to the regulation of lipid metabolism.In conclusion,fermentation can improve feed quality.Adding fermented corn-soybean meal feed to laying hens’ diet can reduce feed egg ratio,improve albumen height and Haugh unit,reduce cholesterol content,improve small intestinal mucosal morphology and enhance intestinal barrier function.Comprehensive production performance,lipid metabolism and intestinal health indicators,the feeding effect of Lactobacillus salivarius fermented feed is better than that of Clostridium butyricum and Lactobacillus crimpus fermented feed.