Влияние пробиотика «Энзимспорин» на морфофизиологические показатели гибрида ленского осетра и белуги при выращивании в аквакультуре

Abstract

The use of probiotics is recommended for sustainable growth, increased resistance and efficiency of feed assimilation. Currently, there are commercial probiotic products prepared from the bacteria Bacillus sp., Lactobacillus sp., Enterococcus sp., Carnobacterium sp. The use of the probiotic supplement “Enzimsporin” in fish farming is in its infancy. However, information is available on the effectiveness of its use in rainbow trout. In this regard, an urgent task is to study the effect of the probiotic “Enzimsporin” on the morphophysiological parameters of the juvenile hybrid of Lena sturgeon and beluga (Lenbel) under existing cultivation conditions. At the initial stage, the fish were divided into 8 groups of 50 fish each according to the principle of pairs of analogues. Large and small individuals were divided into four groups: control and experimental with a dose of Enzimsporin of 1 g/kg, 1.5 g /kg and 2 g/kg of feed, respectively. The duration of the experiment was 60 days. Total catches were made at the beginning and end of the experiment, and intermediate catches were made every 15 days, individually weighing 25–35% of the total number of fish in the pool. The physiological state and immune status of Lenbel were assessed by hematological and cytochemical parameters. Blood for analysis was collected from the caudal vein of fish in vivo. Leukocyte composition and the proportion of immature cell types were determined in Pappenheim-stained peripheral blood smears under a digital microscope. The phagocytic activity of fish neutrophils was evaluated by a lysosomal cation test using a cytochemical method with bromophenol blue. During the two months of the experiment, the main hydrochemical parameters (pH, nitrites, nitrates, ammonium), water temperature and the dissolved oxygen content were within the technological norms. The best absolute and relative growth rates were obtained in the experimental groups receiving a probiotic at a dose of 1.5 g/kg of feed. These fish had high indicators: absolute and relative growth, absolute and relative growth rate, mass accumulation coefficient. The best survival rate was recorded in the group of small yearlings of Lenbel at a probiotic dose of 2 g/kg of feed. In large fish, the maximum survival rate (80%) was recorded at a dose of 1 g/kg of “Enzimsporin”. There is significantly more lysosomal cationic protein in the blood neutrophils of the experimental groups – activation of cellular immunity.