Effect Of Hermetia Illucens Larvae On Growth Performance Of Weaned Piglets And Diarrhea Caused By ETEC

Hermetia illucens larvae meal is rich in protein,fat,amino acid,calcium,chitosan and other substances,which is a high-quality protein feed resource.In this study,according to the nutritional requirements of weaned piglets,the effects of Hermetia illucens larvae meal on growth performance and diarrhea induced by ETEC K88 of weaned piglets were studied by adding 4%and 8%Hermetia illucens larvae into the feed to replace part or all fish meal.In this study,48 ternary female weaned piglets were randomly divided into 3groups,each with 8 pigs,two replicates,and each group was fed with a different proportion of Hermetia illucens larvae meal feed(0,4%,8%;C,HI4,HI8).The growth test was 28 days.The ADG,ADFI and F/G of each group of weaned piglets were calculated,feces were collected and the digestibility of dry matter,crude protein,crude fat and Ca phosphorus was determined by the acid insoluble ash method.Serum was collected and tested on the 28th day Serum biochemical indicators,etc.On the29th day,8 weaned piglets were randomly selected from each group,and the diarrhea was recorded by oral gavage of ETEC K88 50m L(10~9CFU/m L).On day 32,4 piglets were selected from each group to collect serum,colon contents,and intestines.Tract tissue and jejunum,ileum and colon mucosa samples were tested.The results of the first 28 days’growth experiment showed that the supplementation of Hermetia illucens larvae meal in the diet had no effect on the ADG,ADFI and F/G of weaned piglets.The digestibility and absorption of protein,P and Ca in diets supplemented with 4%and 8%Hermetia illucens larvae meal could be significantly improved.Stool16S r RNA sequencing results showed that the abundance of lactic acid bacteria in group HI4 and HI8 was significantly higher than that in group C,and the abundance of streptococcus and staphylococcus in group HI4 and HI8 was significantly lower than that in group C.The Hermetia illucens larvae meal can regulate the microbial composition of the intestines and improve the intestinal health of pigs.After oral administration of ETEC K88 to weaned piglets,the rate of diarrhea was lower in the the Hermetia illucens larvae meal supplement group.Paraffin sections showed that the ileal villi in the C+K88 group were more severely damaged,while the ileal villi in the HI4+K88 and HI8+K88 groups were higher in height,lower in crypt depth,and higher in villus height/crypt depth.The expression of aquaporins AQP1 and AQP3 in the ileal mucosa of the HI4+K88 group was significantly higher than that of the C+K88 group(P<0.05).The expression levels of ion transporters NHE3 and CFTR in the HI4+K88 group and HI8+K88 group were significantly higher than those in the C+K88 group(P<0.05).The activities of CAT and POD in serum of HI4+K88 group and HI8+K88 group were significantly higher than those of C+K88 group(P<0.01).The Ig G and Ig A levels in serum of HI4+K88 group were significantly higher than those of C+K88 group(P<0.05).Compared with the C+K88 group,the anti-inflammatory factor IL-10 expression in the jejunum,ileum,and colon mucosa of the HI4+K88 group and the HI8+K88 group increased(P<0.05).The expression of TNF-αin jejunum and colon mucosa of HI4+K88 group was significantly lower than that of C+K88 group(P<0.05).The expression of tight junction proteins Occludin and Claudin-3 in the jejunum,ileum,and colon mucosa of the HI4+K88 group and HI8+K88 group was significantly increased compared with the C+K88 group.Western blotting also verified the expression of these tight junction proteins.After ETEC infection,the HI4+K88 group and HI8+K88 group showed better immune performance,and the integrity of the intestinal barrier was better maintained.The results showed that the Hermetia illucens larvae meal could completely replace fish meal as protein source in feed,increase lactobacillus content,reduce streptococcus content,improve disease resistance,improve immune performance of pigs,and improve intestinal health,it can also promote the transformation and absorption of unsaturated fatty acids and regulate the composition of medium and long chain fatty acids in colon segment.These studies provide new ideas for the use of Hermetia illucens larvae meal as a sustainable protein source in pig feed.