This study aims to evaluate the dietary replacement effect of various levels of fish meal (FM) with meat meal (MM) on the growth, feed utilization, chemical composition, hematological parameters, and innate immune responses of olive flounder. A total of 360 juvenile fish (initial weight of 14.7 g) were randomly assigned to 18 flow-through containers. The control (MM0) diet included 65% FM. Then, 10%, 20%, 30%, 40%, and 50% FM in the MM0 diet were replaced with MM, referred to as the MM10, MM20, MM30, MM40, and MM50 diets, respectively. The fish were hand-fed to satiation daily for 56 days. Weight gain, the specific growth rate, the feed efficiency ratio, and the protein efficiency ratio of fish fed the MM0 diet were statistically greater than those of fish fed the MM30, MM40, and MM50 diets, but not statistically different from those of fish fed the MM10 and MM20 diets. To incite the maximum values of weight gain and the specific growth rate (SGR) of the fish, an estimated 7.0% of FM substitution with MM in diets was required according to regression analysis. However, the feed consumption, protein retention, hematological parameters, and innate immune (superoxide dismutase and lysozyme activities) responses of the fish were not statistically impacted by the dietary replacement levels of MM for FM. In conclusion, the feed ingredient grade of MM can substitute FM by up to 20% in the diet without causing any negative impact on the growth, feed consumption, feed utilization, or innate immune responses of olive flounder.

Fish seed are important for the growth of aquaculture in Bangladesh, but there are many challenges associated with supplying quality fish seed. This review evaluated the current level of production, issues and challenges that are affecting the production of fish seed in Bangladesh. The fish hatchery was found to be the major contributor in terms of fish seed production. Out of 671 metric tons of fish seed produced in 2020–2021, above 99% were from hatcheries. Freshwater finfish hatcheries have expanded over the last 30 yr, and are distributed throughout the country, but there is no commercial hatchery for coastal and marine water finfish species in the country. Shrimp and prawn hatcheries are concentrated in Cox's Bazar and the greater Jassore regions, respectively, while crab culture is entirely dependent on wild capture. Crablets are collected from nature, which has a devastating impact on biodiversity and wild stocks. The fish seed value chain is multidirectional and interlinked, and intermediaries dominate the supply chain. Disease outbreaks and indiscriminate use of chemicals are major concerns in fish seed production. Management strategies such as the introduction of certification, training programs, technology transfer, access to credit, and implementation of the law could improve the quality and productivity of fish seed in Bangladesh.

The effect of Nigella sativa (black cumin) seed extracts supplemented diets at 2%, 4% and 6% doses with common diet as control (0%) fed to common carp, Cyprinus carpio against Pseudomonas fluorescens was investigated critically on weeks 1, 2 and 4 as immunomodulator. Immunological factors including bactericidal activity and phagocytic action were examined along with the disease resistance. The outcomes of the research recommend 4% dose of N. sativa oil enriched diet as an effective immune response and disease resistance agent for C. carpio against P. fluorescens although further investigation will facilitate to optimize the precise quantity comparing with the weight of fish body.

Inclusion of various sources of additives in aquafeeds is practically helpful to elevate the growth performance and disease resistance of aquatic animals. An 8‐week feeding trial was conducted to determine the inclusion effects of phyto‐additives (yacon, ginger, and blueberry) into diets on olive flounder growth, feed utilization, chemical composition, and plasma chemistry, and to challenge test against Edwardsiella tarda in comparison to a commercial probiotic SUP (Super lacto®). Six hundred juvenile olive flounder were randomly allocated into 15, 50 L flow‐through tanks (40 fish per tank). Five experimental diets were formulated. No additive was included in the control (Con) diet. One percent of yacon, ginger, and blueberry powders, and 0.5% Super Lacto® were included at the expense of wheat flour and water in the Con diet, also referred to as the YCP (yacon powder), GGP (ginger powder), BBP (blueberry powder), and SUP diets, respectively. All experimental diets were hand‐fed to triplicate groups of fish twice a day until they were visually satiated for a period of 8 weeks. Following the 4‐ and 8‐week feeding trials, 10 and 20 fish were taken from each tank and artificially infected with E. tarda, and then survival was monitored for the next 6 and 8 days after infection, respectively. At the end of the 8‐week feeding trial, no significant difference was observed in weight gain, feed consumption, feed utilization, chemical composition, and plasma chemistry in olive flounder. However, the survival of olive flounder fed the GGP diet was significantly (p < 0.004 and p < 0.02, respectively) higher than that of fish fed the SUP, BBP, and Con diets, and the SUP and Con diets after the 4‐ and 8‐week feeding trials, respectively, according to the Kaplan–Meier survival curve. In conclusion, phyto‐additive, especially GG, can be used as an effective immunostimulant in the olive flounder diet at the occurrence of E. tarda.

This study was conducted to determine the growth performance, body composition, and haematological profile of Heteropneustes fossilis in response to the replacement of fish meal (FM) by sunflower meal (SFM). The experiment was conducted in a completely randomized design (CRD) with five treatments and three replications. The fish (initial average body weight of 2.42 ± 0.01 g) were reared in 15 glass aquaria (40 fish/aquarium) with a 150‐L water capacity. Five isoproteic (35%) diets were prepared by replacing FM protein with SFM protein at a rate of 0% (T₀), 10% (T₁₀), 20% (T₂₀), 30% (T₃₀), and 40% (T₄₀). Fish were fed with experimental diet twice a day (9.00 and 16.00), 7 days a week for 8 weeks. Fish were sampled at the end of the experimental period of 8 weeks. At the end of the rearing period, the highest weight gain (6.25 ± 0.11g), % weight gain (163.32%), and specific growth rate (1.61 ± 0.03%/day) were observed in the control (T₀) treatment, but the difference was not significant (p > 0.05) with T₁₀ and T₂₀ treatments. However, all the growth factors were decreased with the further inclusion level of SFM in replacement of FM, and the lowest growth performance was observed in T₄₀ treatment. The protein efficiency ratio (PER) and feed conversion ratio (FCR) followed the same pattern as the growth parameters. It was found that the whole‐body proximate composition of fish was also affected significantly (p < 0.05). Haematological parameters significantly (P < 0.05) altered at 30% and 40% levels of replacement of FM with SFM. Based on these results, it can be concluded that 20% FM protein can be substituted with SFM protein in the diet of H. fossilis without compromising growth performance, feed utilization, chemical composition, and haematological status. However, according to polynomial regression analysis, the optimum level of replacement of FM protein with SFM protein was determined to be 14.3% in the diet of H. fossilis.

The study was conducted on the hatchery labors in some selected area of Jessore Sadar Upazila in Bangladesh under the district of Jessore by using a logical questionnaire on socio-economic condition of hatchery labor. The main objective of the study is to know the socio-economic condition of the hatchery labors in some selected area of Chanchra region of Jessore district. The specific objectives are to know the different labor categories in hatcheries of Chanchra region and to know the socio-economic condition of hatchery labors. A total of 40 hatchery labors were selected and interviewed. It was found that the average age group of hatchery labor is 26-35 years, predominantly all of them are male and any presence of female labor was not found. It was found that about 95% labor use tube-well water and 5% use deep tube-well water. Regarding mean of transport, 65% labor move by on foot. It was found that about 75% hatchery had no medical treatment facility. However, further study about the socio-economic condition is needed and institutional, organizational, technical and credit supports are needed for their better socio-economic and sustainable livelihood.