The Attenuate Effects Of Gly-Glu-Zn On The Diarrhea Of Pre-Weaning Calves

Gly-Glu-Zn is an organic zinc chelated with dipeptides and zinc ions.Organic zinc is characterized by high biological activity,high absorption rate and high utilization rate.Besides,Gly-Glu-Zn also has nutrition and immune functions.Previous studies have shown that organic zinc has the effect of alleviating diarrhea in young animals.However,it is not clear whether Gly-Glu-Zn can alleviate calf diarrhea.This research investigated the effects of Gly-Glu-Zn on the diarrhea rate,growth properties,blood biochemical parameters,intestinal flora and metabolites of intestinal flora of Holstein calves by feeding Gly-Glu-Zn.The purpose is to study the effect of Gly-Glu-Zn on calf diarrhea.The aim is to reduce the incidence of diarrhea in calves,ensure their health,and provide theoretical basis for the development of new additives.30 Holstein calves around 7 days old have been selected from the herd based on the principle of similar weight and date of birth,and divided into three groups(n=10)randomly.After morning feeding,the Con group were fed with 50 m L purified water,low zinc group were fed with 50 m L low concentration Gly-Glu-Zn solution(The zinc content is equivalent to 80 mg/day),high zinc group were fed with 50 m L high concentration GlyGlu-Zn solution(The zinc content is equivalent to 160 mg/day).The experimental lasted for 14 days.Body weight was measured at d0,d7 and d14,and fecal scores were recorded daily.Immune and antioxidant indicators of d7 serum were measured.16 S r RNA sequencing and metabolomics analysis were used to explore the effect of Gly-Glu-Zn on intestinal flora and metabolites.The main results are as follows:(1)The statistics results of diarrhea rate: Feeding high concentrations of Gly-Glu-Zn significantly reduced fecal scores(P<0.05)from d7 to d12.(2)The antioxidant capacity of calves has been enhanced by Gly-Glu-Zn,High concentrations of Gly-Glu-Zn significantly increased the concentration of CAT(P<0.05)in serum,significantly reduced the concentration of MDA(P<0.05);High concentration of Gly-Glu-Zn significantly increased the concentration of CAT(P<0.05)in serum.(3)Low concentration of Gly-Glu-Zn significantly increased the concentration of immunoglobulin sIgA(P<0.05)in rectal contents;High concentration of Gly-Glu-Zn significantly reduced the concentration of pro-inflammatory factors IL-2 and IFN-γ in serum(P<0.05),significantly increased the concentration of immunoglobulin sIgA(P<0.01)in rectal contents.(4)Low concentration of Gly-Glu-Zn significantly increased the concentration of valerate in d7 rectal contents(P<0.05);High concentration of Gly-Glu-Zn reduced the concentration of propionate in d14 rectal contents(P<0.05).(5)Microbiomics results: At the phylum level,both low and high concentrations of Gly-Glu-Zn significantly reduced the relative abundance of Proteobacteria(P<0.01).At the genus level,low concentrations of Gly-Glu-Zn significantly reduced the relative abundance of the Staphylococcus(P<0.01);High concentration of Gly-Glu-Zn significantly reduced the relative abundance of Erysipelotrichaceae＿UCG＿009(P<0.01).(6)Metabolomics results: The metabolites of low concentration zinc treatment group has significant difference,and 108 biomarkers were screened out;high concentration zinc treatment group also has significant difference,and 112 biomarkers were screened out.Comparing the metabolites between the experimental groups,the results of metabolite enrichment indicate that Gly-Glu-Zn may affect the metabolic pathway of vitamin digestion and absorption.Conclusion: Gly-Glu-Zn reduces the diarrhea rate of pre-weaned calves,improves their antioxidant and anti-inflammatory abilities,and has the function of regulating intestinal flora and metabolic pathways,thereby achieving the goal of alleviating calf diarrhea.