The results of the continuation of work on the factory reproduction of tench (Tinca tinca L.) in the Saratov region

Abstract

The present research is a continuation of experimental work on the factory reproduction of tench in the Saratov region. The purpose of our research was to develop elements of biotechnics that optimize artificial reproduction of tench, since the practice of obtaining larvae of this species of fish in fish farms is extremely limited due to the lack of effective methods of its factory reproduction. The objects of research were breeders of tench caught in the Volgograd reservoir and adapted to growing in pond conditions for two years. Two schemes for stimulating puberty of female tench with acetonated carp pituitary gland were used in the work. The first group of females was injected with pituitary solution twice; the second group was planned to be pierced three times by the pituitary gland. After 19 hours, ovulated oocytes were received from 3 females of the second group, stimulated only by two preliminary injections of the pituitary gland. The other two females of this group received eggs after a further three hours. In the females of the first group, who were injected twice, it was possible to obtain ovulated oocytes only in one 21 hours after the permissive injection. Male tench were injected once simultaneously with the pre-injection of females. Methods of de-gluing fertilized eggs with the help of proteolytic enzymes alkalase and neutrase have been studied. The solution of the enzyme alkalase at a concentration of 3 ml/liter of water and an exposure of 1 minute showed a well-pronounced de-gluing activity, followed by incubation of fertilized eggs with a larval yield of up to 80%. The second batch of ovulated oocytes was desaturated with a neutrase solution at a similar concentration and exposure as alkalases. The results of de-gluing were unsatisfactory, since the eggs were constantly glued to the walls of the flask of the Weiss apparatus.