Abstract
The feasible strategies to keep up the growth and wellbeing of aquatic organisms by using beneficial dietary additives are highly recommended. Among these additives, beta-glucan (BG) and mannanoligosaccharide (MOS) were examined on common carp performances in the current experiment. For 80 days, carps were fed four diets with 0%, 1%, 2%, and 3% BG/MOS (1:1) and distributed in four groups (triplicates). Higher final weight and weight gain (P<0.05) were detected in carps fed 1%, 2%, and 3% of BG/MOS than the control group. The feed conversion ratio showed lower values (P<0.05) in carps fed BG/MOS mixture at 2%, and 3% than 0% and 1% levels. The activities of amylase, lipase, and protease were higher in fish fed BG/MOS mixture than in the control group. Interestingly, fish fed BG/MOS mixture had markedly increased villi length and width with branched villi integrity. Further, the count of goblet cells was increased (P<0.05) in groups fed BG/MOS mixture than in carps fed the basal diet. The hemoglobin and hematocrit levels and the counts of red and white blood cells were higher in carps led BG/MOS mixture than the control with the highest counts in 3% level. Additionally, the blood total protein, globulin, and phagoeytic activity were higher (P<0.05) in groups that received BG/MOS mixture at 3% than the control. The lysozyme had a higher value in 1% group than the control (P<0.05). Therefore, using the mixture of BG/MOS at 2-3% is suggested for improving the growth rate, intestinal health, blood health, and immunity of common carp.