Effect of dietary administration of lactobacillus plantarum on reproduction related genes expression Vitellogenin and Estrogen receptor and cyp19a) Sex hormones ( progesterone, estradiol) and histology of gonad in female of zebrafish (Danio rerio) on Sex hormone estradiol and histology of gonad in female of zebrafish (Danio rerio)

The objective of this study was to investigate the effect of different levels of Lactobacillus plantarum probiotic on estradiol hormone and gonad tissue in zebrafish (Danio rerio). So, six hundred healthy zebrafish (0.15+0.01 gr) were randomly distributed in 12 glass aquariums and fed experimental diets contain different levels of L. plantarum (0%, 105, 106 and 107CFU/gr ) for 3 months . After this period and sex determination, males were seprated and females fed probiotic for 1 month more. At the end of the experiment, the whole body of the fish was used to measure the hormone, the amount of esteroid hormone was measured by RIA method. Also of the histological point of view were studied by light microscope. The results of this study showed an increase in the amount of estradiol hormone during vitellogenesis in fish fed 106 CFU/gr L. plantarum which had a significant difference with other treatments (P <0.05). However, 107 CFU/g fed L. plantarum treatment had a decreasing trend. In tissue sections, the most of the eggs in control were clearly in the second and third stages of sexual maturation while in the 106 CFU/gr fed treatment, most of the eggs were in the third and fourth stages and even at the end of the fourth stage of maturation.These stages were more common than treatments fed 105 CFU/g and 107 CFU/g L. plantarum. The results of the present study indicated that the use of probiotics L. pentarum in the effective amounts can be considered as a new strategy to improve reproductive performance.