BACKGROUND: Enzymes are organic catalysts that trigger and/or accelerate chemical reactions. OBJECTIVES: This research was done to compare the separate and combined levels of commercial multienzymes on feeding efficiency and carcass chemical composition of common carp (Cyprinus carpio). METHODS: Total number of 96 common carp fingerlings weighing 13.06±2.56g were distributed in six treatments including control (without multienzyme), 1 g/kg Combo, 1.5 g/kg Combo, 1 g/kg Natuzyme Plus, 1.5 g/kg Natuzyme Plus and mixture of 1g/kg Combo+1 g/kg Natuzyme Plus in two replicates for 8 weeks. RESULTS: Growth indices such as the final weight, percentage of body weight increase, specific growth rate, food conversion ratio and average daily growth in treatment 1g/kg Natuzyme Plus showed significant differences compared to other experimental treatments (P<0.05). Also, all experimental treatments had better condition in comparison with the control. The highest condition factor was seen in fish fed 1.5 g/kg Natuzyme Plus which showed significant difference with 1.5 g/kg Combo (P<0.05). Common carp fingerlings fed mixture of Combo+Natuzyme Plus recorded a slight increase in protein content of carcass compared to other dietary treatments. Fish fed multienzymes had less (P>0.05) lipid content of carcass in comparison with the control. There was no significant difference in ash and moisture contents of carcass (P>0.05). CONCLUSIONS: According to results, it can be stated that Natuzyme Plus at the level of 1.5 g/kg can be effective in improvement of growth performance and feed efficiency in farmed common carp fingerlings.

BACKGROUND: Probiotics and prebiotics are the most important bioactive compounds for aquatic health. OBJECTIVES: In this study, the effects of prebiotic (immunowall) and probiotic (primalac) were assessed on growth performance, survival, body composition, and blood biochemical parameters in the Caspian Sea common carp Cyprinus carpio fingerlings. METHODS: Juveniles (n = 100 per tank, 21 tanks) were distributed in four inclusion levels (each in three treatments) of 0, 0.05, 0.1 and 0.15% of immunowall and primalac inclusions for a period of 56 days. Growth, body composition, and hematological parameters have been evaluated in different inclusion levels at the end of culture period. RESULTS: The increment of body weight, specific growth rate, and feed conversion ratio in fish fed with diets containing 0.15% prebiotic and 0.1% probiotic improved considerably compared to other treatments. The survival rate of the juveniles was not significant between treatments, and the group fed with the pre- and probiotics revealed higher survivals. Protein content in the group fed with the pre- and probiotic showed significantly higher contents compared to the control group, and lipid content showed increasing trend in different inclusions. The red blood cells contents showed no differences between treatments; but the white blood cells contents revealed higher performances in the fish-fed probiotics compared to prebiotic and control groups. CONCLUSIONS: These results recommend the addition of 0.1 % immunowall and 0.15 % primalac in the diets of the juveniles in terms of growth, feeding, and hematological indicators in the Caspian carp.