Effects of different levels of galactooligosaccharide on growth, biochemical body composition, and blood indices in juvenile common carp, Cyprinus carpio

In this study, in order to use prebiotics as one of the best solutions to maintain the health of farmed aquatic animals and increase their resistance against pathogens instead of antibiotics, the effects of different levels of galatooligosaccharide (GOS) prebiotics on growth performance, biochemical body composition, and some blood serum indices were investigated. Therefore, two hundred and forty fish were randomly distributed into 12 tanks with capacity of 100 L in four treatments with three replicates. Experimental treatments included control (no GOS added), T1: 1% dietary GOS added, T2: 2% dietary GOS, and T3: 4% dietary GOS. The fish were fed ad libitum two times daily for 8 weeks. The results showed that GOS improved growth and nutritional performance, body biochemical composition, and some blood serum indices in common carp. T2 exhibited the highest performance in terms of final weight (32.58 ± 1.08 g), food conversion ratio (1.57 ± 0.09), protein content of the body (14.78 ± 3.77%), serum total protein (4.66 ± 0.18 g/dL), globulin (3.34 ± 0.15 g/dL), and some other biochemical parameters of blood. Therefore, 2% dietary GOS had beneficial effects on performance of juveniles common carp.