Fishery-biological indicators and disease prevention of common carp (Cyprinus carpio) due to the use of innovative additives in feed

The work aimed to comprehensively study the impact of innovative feed additives on the physiological state, growth, and development of common carp (Cyprinus carpio). The object of the research was two-year-old common carp (Cyprinus carpio). Three hundred fish specimens were selected for the experiment, with an average initial weight of ~250 g. All selected fish were divided into three groups of 100 specimens each: the Control group (C) received standard feed without innovative additives. Experimental group 1 received feed with the prebiotic inulin. Experimental group 2 received feed with probiotics containing Bacillus spp. and Lactobacillus spp. The studies found that at the end of the year, the live weight of fish receiving innovative additives was higher, compared to the control group, by 70 g when using inulin and by 120 g when using probiotics. Optimal growth of carp is observed at water temperatures of 20–24 °C (June–August), after which the growth rate decreases. Adding inulin and probiotics to the feed improves protein digestion. It increases the moisture content of the intestinal contents, especially in the group with probiotics, reducing their fat component and carbohydrate content. Inulin also positively affects the composition of the intestinal contents, especially in terms of protein digestion, but its effect is less pronounced than that of probiotics. Adding inulin and probiotics improves the sanitary condition of water bodies, an essential factor in maintaining fish health and ecological balance. Both additives demonstrate a similar effect in reducing microbial pollution, which indicates their effectiveness in improving the quality of the aquatic environment. Feeding fish with probiotics and inulin significantly improves their productivity, increases survival, feed digestion, and contributes to greater weight gain. The most effective probiotics provided the highest average daily gain, the best feed conversion ratio, and maximum survival.