Herbal Feed Additives for Gonadal Maturity and Breeding Performance of Female Snow Trout (Schizothorax richardsonii) in Captive Condition

Abstract

Addressing the issue of gonadal maturity and breeding in captive condition for a commercially important indigenous Coldwater fish, snow trout, Schizothorax richardsonii, field study was conducted with dietary supplementation of the blend of Ashwagandha (Withania somnifera) root powder, dried powder of garlic (Allium sativum), and hing (Ferula asafoetida). Experimental fish of 3 years age were reared in FRP tanks (n = 4) of 1200 L capacity with stocking density of n = 60 in each tank and fed with control (CD) and experimental (TD) diets in duplicate at the feeding rate of 3–5% of their body weight twice in a day. Gonadosomatic index (GSI) and hepatosomatic index (HSI) were recorded for annual breeding cycle coupled with breeding indices in breeding season and regular monitoring of water quality parameters. In female stock, the GSI values ranges from 0.87 to 12.83 and 1.84 to 15.42 in control and treated groups, respectively. Two peaks of GSI values reflects the two breeding season of the species during the month of March and September. Similarly, HSI was lowest during the month of March and September in captive reared female fish and highest during the month of May to June and January to February, with similar trend in both, control treated and groups. In captive condition, 80% specimens were observed mature for spawning in treated group, while only 15% females were ready to spawn in control stock. The fecundity of the fish was observed in the range of 20210-23710 eggs/kg body weight with 80–94.2% fertilization rate. The egg size was observed in the range of 3.5–3.8 mm. The study revealed that 1.0% supplementation of blend of herbs in the diet is beneficial for gonadal maturity of females and better spawning of S. richardsonii in captive Coldwater condition.