Grey mullet is a potential species for diversification of aquaculture due to fast growth, omnivorous feeding habits and the high market value of the fish as well as its value-added products such as salt-cured and dried eggs called 'bottarga' (Vinatea et al., 2018;Whitfield et al., 2012). The euryhaline and eurythermal characteristic of grey mullet helps in better adaptation to captive condition and makes it a suitable candidate for brackish water aquaculture.The nutritional attributes such as ω-3 and ω-6 fatty acids and essential amino acid contents make grey mullet as an appropriate

An experimental trial was conducted for 90 days to evaluate the effect of different carbon sources viz. yam and potato on growth performance of milkfish (Chanos chanos) in biofloc‐based system. Milkfish fry (average body weight of 0.66 ± 0.01 g) was stocked in biofloc treatments, yam‐based biofloc (BFY) and potato‐based biofloc (BFP), and clear water (CW) as control in triplicates. Milkfish reared in biofloc‐based units obtained significantly better (p < 0.05) performance in terms of growth, digestive enzyme activity and survival when compared to clear water control. Among the biofloc‐based treatments, the highest average body weight (11.62 ± 0.24 g), specific growth rate (3.21 ± 0.01% day−1), percentage weight gain (1688.10 ± 19.05) and survival (90.83 ± 2.01%) were found in BFY group. Similarly, the essential amino acid and non‐essential amino acid contents of biofloc and experimental fish were higher in BFY as compared to BFP. Additionally, the highest level of EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid) and total n‐6 and n‐3 PUFA were found higher in BFY. Bacterial composition analysis showed that BFY treatment groups had a more diverse bacterial community than those with BFP treatment groups. This study demonstrated that biofloc‐based culture system is suitable for rearing of C. chanos fry and the most preferable type of carbon source is found to be Yam.

The availability of zinc has been correlated with reproductive performance. To validate the hypothesis, a 60‐day feeding trial was conducted to evaluate the effect of dietary zinc on reproductive performance and gonadotropin gene (FSH and LH) expression in threatened Clarias magur brooder. Four isonitrogenous (35%) and iso‐energetic (372.18 ± 1.73 k cal/100 g) diets were prepared with zinc acetate as control (100 mg/kg diet normal requirement), T1 (50 mg/kg diet, low zinc), T2 (200 mg/kg diet, medium zinc) and T3 (300 mg/kg diet, high zinc). The weight gain % and specific growth rate were significantly (p < 0.05) decreased with the increased dietary zinc level. The pituitary mRNA levels of FSH were assessed during the reproductive cycle of female C. magur, and the FSH expression was increased which was significantly (p < 0.05) highest in T1 group. Similarly, LH expression was revealed to be highest. In all treatment groups except T1, GTH expression reduced significantly by increasing zinc inclusion in the diet. GSI and fecundity were lowest during initial sampling and start to increase was observed. The highest GSI and fecundity were recorded in the T1; however, GSI and fecundity significantly (p < 0.05) reduced with increasing the zinc level. Reproductive parameters like spawning fecundity, fertilization rate, hatching rate and larval survival were found to be dose‐dependent of zinc. This revealed that 50 mg/kg zinc was optimum for enhanced reproductive performance; therefore, the present study proposed that 50 mg/kg of zinc could be supplemented for flexible enhanced reproductive performance in threatened Asian catfish, C. magur.

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Background: Stunting is a process of suppressing growth from unfavourable conditions. The protein supplementation during stunting gives scope to maintain the nutrient reserves of fish and its quality. Methods: A feeding trial was conducted for eight months to study the effect of three hetero-nitrogenous diets with 25% (control), 30% (T1) and 35% (T2) crude protein (CP) levels on growth and physio-metabolic responses of Chanos chanos fingerlings during stunting. Milk fish fingerlings with a mean body weight of 11.71±0.18 g were stocked in earthen ponds @ 20 no/m2 in each replicate (n=3) was fed @ 2% biomass throughout the experiment. Result: Fish fed with T1 diet showed better specific growth rate (0.64±0.01% d-1), weight gain percentage (362.56±14.95) and protease activity (7.53±0.25 U/mg protein). Whereas, lower activity was observed for the enzyme assay, namely superoxide dismutase (45.41±2.50 U/min/mg protein), aspartate aminotransferase (34.01±1.88 U/min/mg protein) and alanine aminotransferase (39.64±0.64 U/min/mg protein). Hence, it may be concluded that the dietary protein inclusion level of 30% CP showed better growth performance and lower physio-metabolic response in milkfish fingerlings during the stunting.