AUTHOR=Jin Xinxin , Yuan Boyu , Liu Mingming , Zhu Mingqiang , Zhang Xue , Xie Gaijie , Wu Wenxiang , Wang Zifan , Xu Haidong , Lv Yantao , Huang Yanhua , Wang Wei 

TITLE=Dietary Hermetia illucens Larvae Replacement Alleviates Diarrhea and Improves Intestinal Barrier Function in Weaned Piglets Challenged With Enterotoxigenic Escherichia coli K88

JOURNAL=Frontiers in Veterinary Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2021.746224

DOI=10.3389/fvets.2021.746224

ISSN=2297-1769

ABSTRACT=<p>A high-quality protein substitute, <italic>Hermetia illucens</italic> (black soldier fly) larvae powder, is rich in protein and often used in animal feed. This study aimed to investigate the feasibility and optimal ratio of replacing fish meal with <italic>H. illucens</italic> larvae in weaned piglets and to demonstrate the effects on piglets' growth performance, intestinal microflora and immune performance. Forty-eight female weaned piglets were randomly classified into three groups. Each group consisted of eight pens (replicates), with two piglets per pen. Three groups containing different proportions of <italic>H. illucens</italic> larvae (0, 4, and 8%) were referred to as C, HI4, and HI8. We first designed a 28-day feeding experiment to detect growth performance; after that, the piglets were induced with oral gavage of enterotoxigenic <italic>Escherichia coli</italic> K88 (ETEC K88) and recording diarrhea on day 29 of the experiment. Samples were taken on the 32nd day to detect the effect of <italic>H. illucens</italic> larvae on the immune performance of the weaned piglets. <italic>H. illucens</italic> larvae replacement did not cause any obvious change in the growth performance nether in HI4 nor in HI8 of weaned piglets with 28 d feeding stage. <italic>H. illucens</italic> larvae could improve the intestinal health of weaned piglets by increasing the content of <italic>Lactobacillus</italic> and reducing the content of <italic>Streptococcus</italic>. Compared with C+K88 group, the diarrhea rate was attenuated for the <italic>H. illucens</italic> supplemented group. The integrity of ileum villi in HI4+K88 and HI8+K88 groups was better than that in C+K88 group, and the villi in C+K88 group were severely damaged. The expression of <italic>IL-10, Occludin</italic> and <italic>Claudin-3</italic> in the intestinal mucosa of the HI4+K88 group and HI8+K88 group were significantly increased (<italic>P</italic> &lt; 0.05), and the expression of <italic>TNF</italic>-α was significantly decreased (<italic>P</italic> &lt; 0.05) compared with the C+K88 group. The results of immunoblotting also validated that the same ETEC K88 treatment of weaned piglets enhanced the expression of tight junction protein in the intestinal mucosa of the <italic>H. illucens</italic> addition group. ETEC-induced diarrhea will be reduced by the diet of weaned piglets containing <italic>H. illucens</italic> larvae, ameliorating the immune performance of piglets. Our results indicates that the optimal dosage of <italic>H. illucens</italic> replacement in weaned piglets is 4%.</p>