Effect of Dietary Mannan Oligosaccharide (MOS) on Growth Performance and Immune Response of Gibel Carp Juveniles (Carassius auratus gibelio)

In this study, we examined effect of mannan oligosaccharides (MOS) on growth performance and immune response of gibel carp juveniles (Carassius auratus gibelio(. After acclimation, fish (6.87 ± 0.21 g) were allocated into 12 aquariums (20 fish per aquarium). Basal diet were supplemented with 0 (control), 1.5, 3 and 4.5 g kg-1 MOS in a totally randomized design trial in triplicate groups. At the end of the trial (8 weeks), growth factors (final weight, weight gain, specific growth rate (SGR), food conversion ratio (FCR), and condition factor) and immune responses (serum Ig levels, lysozyme activity and alternative complement activity (ACH50)) were assessed. The results showed no significant differences in growth and feeding parameters between control and MOS supplementation diets (P > 0.05). The highest and the lowest growth performances were observed in 4.5 g kg-1 MOS and control group (P < 0.05). Subsequently, immune responses (Ig levels, lysozyme activity and ACH50) were significantly higher in 4.5 g kg-1 MOS fed fish (P < 0.05). The survival rate of control group was lower than the MOS groups, but not significant (P > 0.05). These results indicate that MOS at 4.5 g kg-1 of the diet can be considered as a beneficial dietary supplement for improving the growth performance and immune response of gibel carp juveniles.