Comparative physiological and immunological assessment of carp crosses

Abstract

The main purpose of hybridization in the aquaculture industry is improving the productivity of hybrids compared to their parents in specific environmental conditions. The physiological state and resistance are judged by blood parameters, which are sensitive and informative indicators of the state of the body’s defense power and allow timely detection their changes under the influence of abiotic and biotic environmental factors. The article presents the results of studying of the productive and physiological properties of two-year-old carp crosses: interbreed hybrids of the first generation (F1). Shown, that the driveability index of the new threebreed carp cross is significantly lower than that of the “Surskiy Malokostny” and “Petrovskiy” crosses, which characterizes its high commercial qualities. The new three-breed cross has a lower swim bladder index: the lengths of the anterior and posterior chambers are almost equal. The number of vertebrae is less, compared to others. However, in the caudal region the number of vertebrae is close to that of the “Sursky Malokostny” cross and greater than that of the “Petrovsky”. In terms of size and weight indicators, the two-year-olds of the new three-breed carp cross exceeded those of other studied crosses, which indicates significant production potential. All recorded blood parameters of the studied fishes were within the limits of the physiological norm. The new three-breed cross is characterized by a high level of nonspecific cellular protection: a large proportion of microphages — segmented neutrophils is noted in the blood leukogram of the new cross. High immune resistance is evidenced by high vitality and a relatively low content of cationic protein in the lysosomes of neutrophils, which is consumed during immune defense when preparing fish for wintering. A comparative assessment of the crosses showed their excellent and productive marketable qualities, survival at different stages of ontogenesis, and good physiological and immunological status.