An analysis was conducted on both freshwater, coastal and marine fish species to evaluate the concentrations of heavy metals, with the aim of assessing their levels and examining the potential health risks for humans linked to the consumption of contaminated fish. This study estimate concentrations of Cr, Fe, Cu, As, Cd and Pb in 60 individuals belonging to 20 species (10 species for freshwater and another 10 for coastal and marine fishes) by using Atomic Absorption Spectrophotometer. Metal concentrations of Cr, Fe, and Pb in freshwater fishes and Cr, Fe, As, and Pb in marine fishes were exceeded the maximum allowable concentration (MAC). The Estimated Daily Intake (EDI), Average Pollution Load Index (APLI), Target Hazard Quotient (THQ), Hazard Index (HI) and Target Cancer Risk (TCR) of heavy metals were determined for the assessment of human health risk. Ranking order of the values of EDI for freshwater fishes, coastal and marine fishes were Cd > Fe > Pb > Cr > Cu > As and Cd > Fe > Pb > Cr > As > Cu. Highest APLI value of 8.14 (Puntius ticto) that is seriously polluted and 3.003 observed in Otolichthoides pama in freshwater and marine fishes, respectively. THQ_Pb and THQ_As for all the fish species were exceed the safe limit (THQ>1) suggesting potential health risk to consumers. The hazard index for both the fish samples were exceeded the USEPA (United States Environmental Protection Agency) permitted risk level (HI > 1). The target carcinogenic risk value for Cr and As were crossed the USEPA standard limit (TCR> 1E-04), which denotes that continuous consumption of studied fishes may cause health risk to the consumers. On the other hand, sensitivity analysis of freshwater, coastal and marine fishes indicates that all the metal concentrations were responsible factor for health risk.

Shrimp aquaculture has become a vital industry, meeting the growing global demand for seafood. Shrimp viral diseases have posed significant challenges to the aquaculture industry, causing major economic losses worldwide. Conventional treatment methods have proven to be ineffective in controlling these diseases. However, recent advances in RNA interference (RNAi) technology have opened new possibilities for combating shrimp viral diseases. This cutting-edge technology uses cellular machinery to silence specific viral genes, preventing viral replication and spread. Numerous studies have shown the effectiveness of RNAi-based therapies in various model organisms, paving the way for their use in shrimp health. By precisely targeting viral pathogens, RNAi has the potential to provide a sustainable and environmentally friendly solution to combat viral diseases in shrimp aquaculture. This review paper provides an overview of RNAi-based therapy and its potential as a game-changer for shrimp viral diseases. We discuss the principles of RNAi, its application in combating viral infections, and the current progress made in RNAi-based therapy for shrimp viral diseases. We also address the challenges and prospects of this innovative approach.

The fastest-growing aquaculture industry plays a crucial role in fulfilling the increased demand for animal protein. However, the outcomes of the sectors are greatly hindered by unexpected disease prevalence, environmental degradation, organic and inorganic pollutants in aquaculture operations, and ineffective feed exploitation to achieve the global food security goal. There has been little research on the impact of nanotechnology on fish nutrition and improved health, despite the fact that the application of nanotechnology in food production systems is being studied globally. In this respect, scientists are generating and inventing new potential ideas and technology to cope with these challenges in aquaculture. Among them, the use of nanoparticles (NPs) has grown in popularity due to their numerous attractive and distinctive features and also tremendous potential to improve aquaculture production. New ideas regarding the application of NPs in fish medicine, drug delivery techniques through NPs, diet formulation to enhance feed efficacy, and as an antiviral or antimicrobial agent to control disease prevalence in aquaculture systems to augment overall production have been discussed. Commercially cultured fish species, including shrimp, Thai koi, Common carp, Grass carp, and Tilapia, have been shown to respond favorably to a variety of nanoparticles (eg. silver, gold, iron, copper, zinc, selenium, and chitosan). Thus nanoparticles researched-based information in finfish and shellfish aquaculture have short-term or long-term prospects and can be used as a potential candidate for nanomedicines combined with fish feed. These new ideas can be studied further before being utilized commercially in the aquaculture fish feed industries and it has huge merit in the future aquaculture need to be considered. Ann. Bangladesh Agric. (2022) 26 (1) : 113-125

The present study aimed to improve the growth rate of the Bangladeshi native climbing perch (Anabas testudineus) through crossbreeding with Vietnam‐originated climbing perch, which is commercially cultured in Bangladesh. Therefore, crossbred between native and Vietnam strains of A. testudineus were evaluated in the first year (F₁) as T₁—Native ♀ × Native ♂, T₂—Vietnam ♀ × Vietnam ♂, T₃—Native ♀ × Vietnam ♂, and T₄—Vietnam ♀ × Native ♂. In the second year (F₂), backcrosses were performed between native and F₁ generations as T₅—Native ♀ × F₁ (T₃) ♂ and T₆‐F₁ (T₃) ♀ × Native ♂ following five replicates in each treatment group. The F₁ crossbreds of T₄ were irregular in size with low survivability than T₃, and therefore were not used as a parent in the second‐year backcross experiment. The breeding performances were reduced in the T₄ (F₁) and T₆ (F₂) compared to purebreds (T₁ and T₂). The specific growth rate (0.75%/day) of T₅ and T₆ was substantially lower than T₃ and T₄ but was considerably superior to the T₁ and T₂ purebred. The heterosis effect was highly evident in T₆ (27.94%), whereas negative heterosis was determined in the crossbreds of the F₁ generation (T₄). Ten morphometric characteristics were compared and the caudal fin length, pectoral fin length, eye diameter, and body depth were responsible for the variation among T₁–T₆ groups by the second principal component. Furthermore, the results showed that the Bangladeshi native female climbing perch is linked with better breeding performances, and the Vietnam strain male is linked with better growth performance. Finally, the current breeding programme could enhance native climbing perch growth and survivability, which may have aquaculture potential and can be used through careful artificial selection on the commercial farm.

Fisheries and Aquatic Sciences

Striped dwarf catfish (Mystus vittatus) is a valued freshwater species in South Asia for its taste, nutritional profile, and year-round availability. This study evaluated the effects of biosynthesized zinc oxide nanoparticles (ZnONPs) on the growth performance and hematological parameters of M. vittatus. A total of 960 fish (80/aquarium) were reared in twelve aquariums, and fed diets containing ZnONPs at 0 (T0), 50 (T1), 80 (T2), and 110 (T3) mg/kg for 75 days. Treatment T3 showed the highest weight gain (233.33%), specific growth rate (1.60%/day), and protein efficiency ratio (2.01±0.002), along with the lowest feed conversion ratio (FCR) (p0.05). Values at 80 mg/kg appeared more stable, though not statistically validated. Effect size analysis indicated large variance explained by treatment for key indices (η² = 0.31–0.39 for RBC, WBC, Hb, HCT). These values suggest biologically meaningful differences that were not statistically confirmed, likely due to small sample size. By contrast, indices with low effect sizes showed minimal treatment influence, indicating real stability across diets. The survival rate (67.50±0.73%) improved with increasing ZnONPs concentrations, reaching the highest in T3 (p < 0.05). Although mortality was a bit higher, likely due to artificial aquarium conditions and early-stage sensitivity, ZnONPs supplementation still showed a positive effect. These findings suggest that dietary ZnONPs at 110 mg/kg improved growth and survivability in M. vittatus without adverse hematological effects. Ann. Bangladesh Agric. 29(1): 89-103