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A major challenge in Clariid catfish seed production is our inability to induce voluntary captive spawning of the brooders. Since voluntary captive spawning had been previously elicited in a Clarias species by simulating natural breeding environment, we speculated that the major obstacle in voluntary spawning might be the absence of an inducing agent that triggers mating response in the brooders. To address the issue, oxytocin was injected to the brooders along with Ovatide (a commercial inducing agent comprising salmon gonadotropin‐releasing hormone analogue and domperidone). Administration of 40 mIU/kg body weight of oxytocin after 12 hr of Ovatide injection resulted in voluntary spawning of the fish (81.5%, i.e. 31 out of 38 trials), with more than 70% hatching rate in simple and low‐cost spawning facilities. Histology of male gonads indicated sustained gamete maturation and the gonads were observed to be visibly turgid in the fish that received both the hormones. In contrast, gamete maturation slackened after 10 hr in the control fish, injected with Ovatide only. Administration of oxytocin along with Ovatide was also observed to induce aggressive sexual behaviour among the males. Neither of the hormones, acting alone, could induce voluntary spawning in the fish or influence sexual behaviour. Our results clearly show that oxytocin plays a significant role in sustaining the male gamete maturation induced by Ovatide and trigger the behavioural mating response, leading to voluntary spawning in C. magur. The results hold potential to make a paradigm shift in the commercial catfish seed production technology. [ABSTRACT FROM AUTHOR]

An experiment was designed to evaluate the requirement of dietary protein for Reba carp, Cirrhinus reba fingerlings using semi‐purified diet. Five isocaloric diets were prepared containing 20%, 25%, 30%, 35% and 40% level of protein using casein, gelatin as a major protein source. The experiment was conducted for 105 days in triplicates to evaluate the growth, survival, feed utilization, carcass composition of C. reba. Mean weight gain was highest (p < .05) in T3. Specific growth rate was highest in T3 and lowest in T1. Similarly, significantly (p < .05) highest net fish yield were recorded in T3. No significant difference was recorded in survivability. Feed conversion ratio, protein efficiency ratio, feed conversion efficiency and protein conversion efficiency were significantly (p < .05) higher for T3 compared with other treatments. Highest carcass protein and lipid values were recorded in T3. So, conclusion can be drawn that 30% crude protein is optimum for overall performance. Furthermore, broken‐line analysis for specific growth rate, final biomass and net fish yield indicated that dietary protein level of 28.148 to 28.253% is optimum for the best growth performance of fingerling C. reba. [ABSTRACT FROM AUTHOR]