Effects Of Lactobacilli On Immunity And Reproduction Performance In Zebrafish (Danio Rerio)

In order to investigate the effect of lactobacilli as probiotic on host immunity and fecundity,this research chosed Lactobacillus planetarium JCM1149, Lactobacillus brevis CGMCC1.2028，Lactobacillus rhamnosus JCM20300to administate the zebrafish and observed theinfluence of lactobacilli on the zebrafish gut microbiota using high throughput sequencingmethod and the expression of immune cytokines IL-1β，TGFβ and NFκBIαA in the guttissue using the Real-Time PCR analysis during the lactobacilli addtion period. After the14dadministration, the immunity of zebrafish were tested by challenge with Aeromonashydrophila NJ-1; In additon, Lactobacillus plantarum JCM1149and Lactobacillusrhamnosus JCM20300were fed to zebrafish (Danio rerio) for30days and the number ofeggs ovulated, the fertilization rate of eggs and the hatching rates and times of eggs wereobserved during the administration period. The expression of genes leptin, kiss2, bmp15, tgfb1,gnrh3and lhgcr,which regulate the reproduction of zebrafish, and the rates of stage V oocytein the ovaries were detected using Real-Time PCR and paraffin tissue section method after30d administration. Followedly, the larvae from different groups were challenged withAeromonas hydrophila NJ-1and expression of immune cytokines IL-1β and NFκBIαA weredetected using the Real-Time PCR analysis in48h post challenge.The results showed that Lactobacillus planetarium JCM1149, Lactobacillus brevisCGMCC1.2028and Lactobacillus rhamnosus JCM20300changed the composition ofzebrafish gut microbiota, decreased the expression of immune cytokines in the gut tissue andimproved the immunity of zebrafish; Lactobacillus plantarum JCM1149and Lactobacillusrhamnosus JCM20300improved the numbers of eggs, the maturation of oocyte and theexpresion of gene leptin, kiss2, gnrh3and lhgcr, and restrained the expressin of gene bmp15and tgfb1. However, the Lactobacillus plantarum JCM1149, with strong adhesive ability,treatments promoted reproduction in a more acute and persistent manner, compared withLactobacillus rhamnosus JCM20300group, with strong adhesive ability. The immunity oflarvae from the lactobacilli group was not enhenced.In conclusion, Lactobacillus planetarium JCM1149, Lactobacillus brevis CGMCC1.2028，Lactobacillus rhamnosus JCM20300could enhanced the immunity of zebrafish; Lactobacillus planetarium JCM1149and Lactobacillus rhamnosus JCM20300couldimproved the reproduction performance of zebrafish.