Changes in gut microbiota, hematological parameters, and immune response following dietary administration of oyster mushroom (Pleurotus ostreatus) in silver carp (Hypophthalmichthys molitrix)

Abstract

The primary aim was to evaluate the impact of oyster mushroom (Pleurotus ostreatus) on the gut microbiota, hematological parameters, and immune response of silver carp (Hypophthalmichthys molitrix). The experimental group was given P. ostreatus powder at 2% of body weight, while the control group was fed with commercial fish feed. Fish were treated with these two feeds for 8 weeks. Culturing of bacteria, hematological tests, and immunological assays were done to evaluate the effect of these feeds on H. molitrix. Physico-chemical parameters of the aquarium were maintained end-to-end during the trial period, such as DO at 5-7 mg L^-1, temperature at 24-28 °C, and pH at 7.0-8.2. The quantitative outcomes from the groups were compared using the t-test. In all three culturing media, such as nutrient agar (NA), tryptic soy agar (TSA), and eosin methylene blue (EMB), the results indicated a significant decrease in bacterial colonies in the treatment group, when compared with the control group. Compared to the control group, the treatment group had a significantly higher RBC count, higher hemoglobin value, enhanced hematocrit levels, MCV, and MCHC. White blood cells (WBCs), neutrophils, and lymphocytes in the treatment group had a significantly higher count than those of the control group. However, the hematological parameter MCH and immune cells, such as monocytes, remained unchanged in the treatment and control groups. Hence, using immunostimulants such as mushrooms in aquaculture increases the body’s natural resistance to infection and facilitates the prevention of various diseases.