Microbial Probiotic Microorganisms in Aquaculture: Effects on Fish Growth, Immunity, and Water Qualit

Abstract

The effect of probiotic microorganisms on growth and immunity of the fish and water quality in aquaculture was studied through a controlled experimental design. All healthy fish were randomly allocated into 4 different treatments including control (no probiotic application), three with increasing doses of a probiotic supplement and each treatment was replicated to reduce experimental error. Fish growth parameters, feed conversion ratio, survival rate and selected immune indicators were followed during the experimental period and water quality was evaluated by determining water temperature, dissolved oxygen, pH, ammonia, and nitrate concentrations. The effects of the treatments were evaluated by one-way analysis of variance (ANOVA) and regression analysis of experimental data to confirm the treatment effects and to find the optimum probiotic concentration to achieve the best biological and environmental results. Probiotic supplementation yielded statistically significant increases in weight gain, specific growth rate, feed conversion ratio, survival, and certain immune parameters compared to the control group and generally resulted in a dose dependent response in these parameters, with a plateau at the highest probiotic supplement. Probiotics supplementation also resulted in significantly better water quality, with lower ammonia, nitrate, more stable dissolved oxygen and pH compared to the control. The probiotic concentration and growth performance as well as water quality parameters showed significant positive correlation up to the determined threshold concentration through regression analysis. The study concludes that probiotic supplementation is a promising method to enhance fish growth, immune status, and rearing water quality in aquaculture systems and provides suggestions on probiotic dosage, aquaculture management practice and future research.