Study on Resistance of Yak Stomach Lysozyme to Mice Diarrhea
This study aimed to express yak gastric lysozyme in PichiaPinkTM Pichia pastoris expression system to explore methods to improve the expression level of recombinant yak gastric lysozyme,and to investigate the therapeutic effect of recombinant yak gastric lysozyme on diarrhea caused by Escherichia coli O111 in mice.Ten mice with similar body weight were selected,and a mouse diarrhea model was established by Escherichia coli O111.After successful modeling,30 mice were randomly divided into six groups,with five mice in each group.A control group,a diarrhea model group,a yak gastric lysozyme group,a recombinant yak gastric lysozyme group,an antibiotic treatment group,and a lysozyme product treatment group were set up,excluding the con-trol group and the diarrhea model group,the rest of the groups were given oral administration,and the feed in-take and body weight of the mice were recorded.On the fourth day,all the mice were sacrificed,and the duo-denal tissue sections were prepared for morphological observation.The intestinal contents were analyzed for Al-pha and Beta diversity.The results showed that the highest expression level of recombinant yak gastric lyso-zyme was observed at 96 h after induction.The molecular weight was about 15.6 ku,and the specific activity was 1 428.58 U/mg.After challenge,the feed intake of the diarrhea model group,the lysozyme product treat-ment group,and the control group was significantly lower than that of the control group(P＜0.05);compared with the control group,the white cell count,lymphocyte count,and neutrophil count of the diarrhea model group were significantly increased(P＜0.01);the pathological observation of the duodenal tissue found that the intestinal villi of the yak gastric lysozyme group increased in length and thickness;the intestinal villi of the re-combinant yak gastric lysozyme group were restored.Alpha diversity analysis showed that the Simpson index of the yak gastric lysozyme group was significantly larger than that of the control group(P＜0.05);the relative a-bundances of Proteobacteria and Citrobacter in the diarrhea model group were significantly increased(P＜0.05);the relative abundances of Firmicutes and Bacteroidetes in the recombinant yak gastric lysozyme group and the yak gastric lysozyme group were increased.This study indicates that yak gastric lysozyme has a good therapeutic effect on diarrhea caused by Escherichia coli.Due to its strong resistance to gastric protease,the o-riginal enzyme and recombinant enzyme of yak gastric lysozyme have certain application potential in the fields of feed additives,food processing,and medical and health care.[Chinese Journal of Animal Nutrition,2024,36(3):1952-1963]
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维普
