Dietary protein requirement of female climbing perch, Anabas testudineus (Bloch, 1792) broodstock

Nutritional components are multifarious amongst different producers, whereas they are just designed for fish farming but not suitable for improving the reproductive performance of brood fish. Climbing perch, Anabas testudineus is one of the candidate species for freshwater aquaculture in Asia. However, there is little knowledge available about the nutrient requirement of A. testudineus broodstock. Therefore, a feeding trial was conducted for 90-days to optimize the dietary protein requirement for reproductive performances of A. testudineus female broodstock. Six iso-energetic (around 400 Kcal digestible energy/100 g), iso-lipidic (8%) and hetero nitrogenous (25–50% crude protein, CP) semi-purified diets namely, 25% CP (T25), 30% CP (T30), 35% CP (T35), 40% CP (T40), 45% CP (T45) and 50% CP (T50) were prepared for feeding the fish of respective group twice daily. Three hundred and sixty (360) adults A. Testudineus (average body weight 18.67 ± 0.09 g) with female and male ratio of 1:1 were randomly distributed in six treatments in triplicate with the stocking density of 20 fish/ tank (500 L water volume) following a completely randomized design. Results indicated that the gonado-somatic index and viscero-somatic index increased significantly (p < 0.05) up to 40% CP then reduced gradually. But intraperitoneal fat content decreased with increasing dietary protein levels. T40 group showed lowest hepato-somatic index. The absolute fecundity was highest (p < 0.05) in 35% dietary protein fed group but found similar (p > 0.05) between T30 and T45 group. Estradiol was significantly lowest (p < 0.05) but highest 17α, 20β di-hydroxy progesterone level were observed in 35% CP fed group. Cortisol was found highest (p < 0.05) in T40, T45andT50groupand lowest in T35 group. Histological observations revealed that the females with higher proportion of vitellogenic oocytes were from 35% to 40% protein-fed groups. After induced spawning, significantly (p < 0.05) higher fecundity of spawning, rate of fertilization and hatching, and survival of larvae were observed in 40% CP fed group. Second-order polynomial regression analysis of fertilization rate (%) and larval survival (%) estimated 39.07–39.21% dietary protein is optimum for gonadal development, oocyte maturation and reproductive performance of female A. testudineus broodstock.