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Silica nanoparticles (Si-NPs) are increasingly prevalent in various industrial applications, potentially impacting aquaculture. The study investigated the effects of dietary Si-NPs on growth performance and its repercussions on muscle compositions in Stinging catfish, Heteropneustes fossilis (H. fossilis). In this study, four isonitrogenous diets containing Si-NPs (0, 1, 2, and 3 mg/kg) were fed to juvenile H. fossilis for 60 days. Several growth indices (weight gain, WG; percent weight gain, %WG; length gain, LG; and specific growth rate, SGR), feed utility parameters (feed conversion ratio, FCR; feed conversion efficiency, FCE; and protein efficiency ratio, PER) and survival rate was assessed at the end of the feeding trial. This study showed significant effects of Si-NPs (2 mg/kg) in the growth and muscle composition of H. fossilis. However, Si-NPs did not significantly affect the feed utility of H. fossilis. The findings of this study recommended that Si-NPs can be effectively supplemented into the diets of H. fossilis for better production.

There has been a consistent interest in the aquaculture industry in the use of plant elements as a substitute for fish meal (FM). The present study aimed to examine the impact of substituting FM with varying proportions of fermented spent coffee grounds (FCG) on the growth performance, feed stability, blood biochemistry, liver, and intestinal histology of African catfish, Clarias gariepinus. Five isonitrogenous diets were formulated with a crude protein content of 32 %. These diets were created with different percentages of FM replacement, specifically 0 % (T1), 10 % (T2), 20 % (T3), 40 % (T4), and 80 % (T5). The fish were then fed these diets for a duration of 70 days. The results showed that fish provided with 10 % FCG (T2) gave the highest improvement (p < 0.05) in growth conditions compared with other treatments. The feed’s physical properties were varying, but floatability and water stability were highest in T2 diets. Total bacteria (TB) in feed and intestine were more elevated in fish fed with 10 % FCG compared to other treatments. The histopathological damage in the intestine and liver morphology was observed when the level of inclusion of FCG was increased in all treatments. In addition, T2 gave the highest value (p < 0.05) in villus length, width, and crypt depth. Some parameters were improved in both blood haematology and blood biochemical parameters, and T2 gave the highest value (p < 0.05) in white blood cells, lymphocytosis, monocytes, red blood cells, haemoglobin, albumin, globulin, total protein, and creatine. In summary, the substitution of 10 % FCG with FM holds potential for application within the aquafeed sector, as it has been observed to contribute to enhanced growth and improved health conditions in African catfish and other freshwater species.

Heavy metal contamination in aquatic environment is a serious concern throughout the world. Metal contamination are responsible for the accumulation of metals within the fish body. And, consumption of these contaminated fish possess serious threat to the associated consumers. In this current study, five commonly cultured freshwater fishes (rui, Labeo rohita; mrigal, Cirrhinus mrigala; silver carp, Hypophthalmicthys molitrix; bata, Labeo bata, and sarpunti, Puntius sarana) were collected from a commercial fish farm of Natore district, Bangladesh to analyze metals levels in edible portion (flesh), and to assess the associated human health risk. Several heavy metals such as zinc (Zn); cadmium (Cd); chromium (Cr); arsenic (As); lead (Pb); and nickel (Ni) were analyzed by a flame atomic absorption spectrophotometer. Besides, the target hazard quotient (THQ), hazard index (HI) and lifetime cancer risk (TR) were also estimated for assessing the associated human health risk. In this study, concentrations of Zn, Cd, Cr, As, Pb and Ni in different fish species were found 6.36 ± 1.48 to 13.31 ± 1.33; 0.017 ± 0.01 to 0.049 ± 0.02; 0.654 ± 0.04; 0.015 ± 0.01 to 0.033 ± 0.01; 0.534 ± 0.11 and 0.08 ± 0.05, respectively. All the analyzed values were within the recommended level except Cr in C. mrigala. The THQ, HI and TR values of all the analyzed metals in the fishes indicated that no associated cancer risk resulting from the consumption of those fishes. Therefore, the current study revealed that fishes of the target area might be free from associated metals contamination and hence, might be safe for human consumption.

Pesticides are from the potent chemical contaminants in aquatic environment. These chemicals are routed into the aquatic environment through several natural and anthropogenic activities. Pesticides toxicity adversely affect growth, physiology, reproduction, immunity, hemato-biochemical profile and induce serious histopathological alterations of several tissues of aquatic organisms including fish. From the aforementioned effects, histopathological and hemato-biochemical parameters serve as important biomarkers of aquatic contamination resulted from pesticides. Pesticides are major concern around the world as they can bioaccumulate into different fish tissues which will consequently result in serious health concern for the consumers. Therefore, searching out of ecofriendly, effective, and suitable alternatives of pesticides is important to protect the aquatic ecosystems as well as health status of several aquatic living organisms especially fish. In this context, the present review depicts several histopathological and hemato-biochemical alterations resulted from pesticide toxicity. It also highlights the possible methods for diminishing the negative effects of pesticides on fish to ensure healthy aquatic environment for fish farming.

Application of dietary feed additives is an excellent approach to improve fish health status under different stressful condition. The current study investigated the roles of different level of dietary gallic acid (GA) on growth performances, biochemical indices, digestive enzymes activity, antioxidant status and immunological responses in common carp (Cyprinus carpio) subjected to crowding stress. Fish were fed with the control diet (0 mg/kg GA) and four graded levels of GA (150, 300, 450 and 600 mg/kg) for 60 days each with three replicates. Moreover, fish were challenged with crowding stress for six hours. The results revealed significant improvement in growth performances, immune indices in common carp fed with dietary GA in comparison to the control diet. The study also demonstrated significant improvement feed utility through enhanced activities of digestive enzymes (amylase, lipase and protease) by dietary GA provision. Moreover, dietary GA noticeably enhanced the antioxidant status of common carp by improving superoxide dismutase, catalase, glutathione peroxidase, and lowering malondiadehyde specially after exposure to crowding stress. Considering these results, the current study reveals that dietary GA at the concentration of 450 mg/kg can successfully improve growth performances, biochemical indices, digestive enzymes activity, antioxidant status and immunological responses in common carp.

Seaweed, also known as macroalgae, represents a vast resource that can be categorized into three taxonomic groups: Rhodophyta (red), Chlorophyta (green), and Phaeophyceae (brown). They are a good source of essential nutrients such as proteins, minerals, vitamins, and omega-3 fatty acids. Seaweed also contains a wide range of functional metabolites, including polyphenols, polysaccharides, and pigments. This study comprehensively discusses seaweed and seaweed-derived metabolites and their potential as a functional feed ingredient in aquafeed for aquaculture production. Past research has discussed the nutritional role of seaweed in promoting the growth performance of fish, but their effects on immune response and gut health in fish have received considerably less attention in the published literature. Existing research, however, has demonstrated that dietary seaweed and seaweed-based metabolite supplementation positively impact the antioxidant status, disease resistance, and stress response in fish. Additionally, seaweed supplementation can promote the growth of beneficial bacteria and inhibit the proliferation of harmful bacteria, thereby improving gut health and nutrient absorption in fish. Nevertheless, an important balance remains between dietary seaweed inclusion level and the resultant metabolic alteration in fish. This review highlights the current state of knowledge and the associated importance of continued research endeavors regarding seaweed and seaweed-based functional metabolites as potential modulators of growth, immune and antioxidant response, and gut microbiota composition in fish.

Water pollution is a threat to aquatic organisms, including fish, and is a global concern for aquatic biodiversity and ecosystem integrity. This study evaluates the effect of waterborne pollutants on Gangetic Mystus (Mystus cavasius) collected from the Surma River, Bangladesh between April 2018 to March 2019. Histomorphological studies of liver and kidney were carried out on 10 individual species collected at each of four sampling sites and one control site. Water quality parameters were also recorded at each site. We observed several histological alterations in the liver, including hemorrhage, pyknosis, necrosis, vacuolation, lipid droplet, nuclear alterations, and hepatocyte hypertrophy. In the kidney, the histopathological alterations included vacuolation, necrosis, hemorrhage, degeneration of glomerular tubule, dilation of Bowman's space and blood congestion. Temperature fluctuated between 19.7 ± 1.57 °C and 32.3 ± 1.74 °C, dissolved oxygen at the surface ranged from 4.15 ± 0.31 to 5.15 ± 0.35 ppm, pH ranged from 7.42 ± 0.33 to 6.50 ± 0.12, nitrite ranged from 0.022 ± 0.21 to 0.817 ± 0.02 mg/l, ammonia ranged from 0.70 ± 0.11 to 0.16 ± 0.19 mg/l and alkalinity ranged from 109.41 ± 0.02 to 14.32 ± 0.20 mg/l during the time frame of the study. Water quality parameters could not found the suitable range from November to February. The main aim of the present investigation revealed that histopathological changes of liver and kidney of Gangetic Mystus appeared to be a useful biomarker to assess the impact of toxicity of water pollution.

Heavy metals pollution causes a threat to the aquatic environment and to its inhabitants when their concentrations exceed safe limits. Heavy metals cause toxicity in fish due to their non-biodegradable properties and their long persistence in the environment. This review investigated the effects of heavy metals on early development, growth and reproduction of fish. Fish embryos/larvae and each developmental stage of embryo respond differently to the intoxication and vary from species to species, types of metals and their mode of actions, concentration of heavy metals and their exposure time. Many of the heavy metals are considered as essential nutrient elements that positively improve the growth and feed utilization of fishes but upon crossing the maximum tolerable limit these metals cause not only a hazard to fish health but also to human consumers and the disruption of ecological systems. Reduced gonadosomatic index (GSI), fecundity, hatching rate, fertilization success, abnormal shape of reproductive organs, and finally failure of reproduction in fish have been attributed to heavy metal toxicity. In summary, this review sheds light on the manipulation of fish physiology by heavy metals and seeks to raise sensitivity to the prevention and control of aquatic environmental contamination, particularly from heavy metals.

Insects such as black soldier fly larvae (BSFL) are gaining interest among researchers and the aquafeed industry due to the fluctuating price and supply of fish meal (FM). This study evaluated the growth performance, feed stability, blood biochemistry, and liver and gut morphology of Betta splendens using BSFL as an alternative to FM. Five formulated diets were prepared: 0% BSFL, 6.5% BSFL, 13% BSFL, 19.5% BSFL, and 24.5% BSFL. The expansion rate, pellet durability index, floatability, bulk density, and water stability of the prepared feed have been assessed. Except for the diameter of the feed, all the parameters studied differed significantly (p

Heavy metals, the most potent contaminants of the environment, are discharged into the aquatic ecosystems through the effluents of several industries, resulting in serious aquatic pollution. This type of severe heavy metal contamination in aquaculture systems has attracted great attention throughout the world. These toxic heavy metals are transmitted into the food chain through their bioaccumulation in different tissues of aquatic species and have aroused serious public health concerns. Heavy metal toxicity negatively affects the growth, reproduction, and physiology of fish, which is threatening the sustainable development of the aquaculture sector. Recently, several techniques, such as adsorption, physio-biochemical, molecular, and phytoremediation mechanisms have been successfully applied to reduce the toxicants in the environment. Microorganisms, especially several bacterial species, play a key role in this bioremediation process. In this context, the present review summarizes the bioaccumulation of different heavy metals into fishes, their toxic effects, and possible bioremediation techniques to protect the fishes from heavy metal contamination. Additionally, this paper discusses existing strategies to bioremediate heavy metals from aquatic ecosystems and the scope of genetic and molecular approaches for the effective bioremediation of heavy metals.

Pesticides and heavy metals are considered as potent contaminants in aquatic environment. Both contaminants are sourced into the aquatic ecosystems by various types of anthropogenic as well as natural practices. Such types of aquatic contamination drastically affect the normal activity of associated living organisms particularly fish. Both the pesticides and heavy metals toxicity cause several negative effects on fish growth, physiology, immune response, reproduction, embryonic and larval development as well as different histopathology of major organs including fish gill, kidney, liver, gonads, and intestine. Besides, the consumption of contaminated fish poses a serious health concern to associated consumers. Considering these serious issues, the current review is designed to investigate the toxic effects of pesticides and heavy metals on different aspects of fishes along with their possible sources, major types, and mode of action as well as role of medicinal herbs to mitigate their toxicity. [ABSTRACT FROM AUTHOR]

Probiotics, an eco-friendly alternative to antibiotics application appears to have strong potential for improving the sustainability of aquaculture. The aim of the study was to evaluate the effect of probiotic brewer’s yeast, Saccharomyces cerevisiae supplementation on growth performance, feed utilization and intestinal morphometry of Nile tilapia, Oreochromis niloticus. A feeding trial of 60 days was conducted in which tilapia fingerlings (7.55 ± 1.25 g) were randomly distributed into three replicate aquaria under four different treatment groups, receiving S. cerevisiae at 0, 1, 2 and 4 g kg−1 diet, respectively. At the end of the feeding trial, growth performance parameters (weight gain, WG; % WG; specific growth rate, SGR), feed utilization indices (protein efficiency ratio, PER; feed conversion ratio, FCR) and intestinal morphology were assessed. The results obtained from this study revealed that growth performance and feed utilization indices were increased significantly in the fish fed with 4 g kg−1 S. cerevisiae supplemented diet compared to controls. The length, width and area of villus were significantly enlarged in fish fed 4 g kg−1 S. cerevisiae supplemented diet. Likewise, intestinal mucosal fold, width of lamina propria, width of enterocytes and number of goblet cells increased in the fish fed with 4 g kg−1 S. cerevisiae supplemented diet. These results demonstrated that S. cerevisiae can be effectively recommended as an important growth promoter for tilapia culture.

Chromium is considered the most detrimental pollutant to the aquatic organisms. The present experiment was conducted to determine the acute toxicity of chromium in view of its effects on hemato-biochemical parameters and the structure of erythrocytes in striped catfish, Pangasianodon hypophthalmus. Fish were exposed to seven different concentrations (0, 10, 20, 30, 40, 50 and 60 mg/L) of chromium, each with three replications for 96 h. After 96 h of exposure, the survived fish were sacrificed to measure hemato-biochemical parameters (hemoglobin, Hb; red blood cell, RBC; white blood cell, WBC; packed cell volume, PCV; mean corpuscular volume, MCV; the mean corpuscular hemoglobin, MCH and blood glucose). In addition, erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) of peripheral erythrocytes were assayed. No mortality was observed up to 10 mg/L, but 90% and 100% mortality was observed at 50 mg/L and 60 mg/L, respectively after a 96 h exposure period. The 96 h LC50 value through probit analysis was 32.47 mg/L. Hb (%), RBC (×106/mm3) and PCV (%) significantly decreased at 20, 30 and 40 mg/L of chromium, whereas WBC (×103/mm3), MCV (μm3) and MCH (pg) showed the opposite scenario. Blood glucose (mg/dL) levels significantly increased at 10, 20, 30 and 40 mg/L of chromium compared to 0 mg/L. Frequencies of ECA and ENA significantly increased with increasing chromium concentrations. This study indicates that chromium is highly toxic to striped catfish.

The use of nanotechnology in food production systems is being investigated globally, though there is limited research on its effect on fish nutrition. Therefore, this study aimed to identify the effects of silica nanoparticles (NPs) on the nutrition and physiology of tilapia, Oreochromis niloticus. Four isonitrogenous diets (300 g/kg crude protein) with NPs (0, 1, 2, and 3 mg/kg diet) were fed to fish (6.52 ± 0.20 g) in a recirculatory aquaculture system for 56 days. Throughout the study period, the effects of silica NP on survival rate, blood cell count, hemoglobin (Hb) level, condition factor (CF), and final product composition (except lipid content) were insignificant. However, growth performance and feed efficiency increased with an increasing level of silica NP, up to 2 mg/kg, and then decreased. This increase was due to the highest apparent protein digestibility and dry matter digestibility when fish were fed silica NP at 2 mg/kg. However, fish at the early stage showed better performance in all dietary groups than in later. Blood glucose (BG) content and histology of the kidney revealed that fish were stressed when a 3 mg/kg silica NP was used and they adapted through excessive excretion via expanded glomeruli. Though no significant effect on villi length was observed, silica NP increased the surface area widening the villi of the gut along with the number of goblet cells in the intestine significantly, when supplemented at a level of 2 mg/kg. The bioaccumulation of silica shows that incorporating silica NP in the fish feed will not compromise human health safety upon consumption. Although silica NP at 1 mg/kg and 3 mg/kg yielded some improvements to growth and final product quality, a 2 mg/kg silica NP generated the best results in all measured parameters.

The analytical experiment was executed to present detailed reports on the concentration of heavy metals (nickel, iron, zinc, manganese, chromium, lead, and cadmium) in farmed shrimp, Penaeus monodon and its concomitant human health risks upon consumption. A total of 147 farms from six sub-districts of Khulna were selected for sample collection and concentration of heavy metals were determined by Atomic Absorption Spectrometry (AAS) method, following electro-thermal heater digestion. Ni and Cr were found considerably below the detectable limit (BDL) in four sub-districts, while Cr found in shrimps from Rupsa and Paikgacha were far higher than the maximum recommended limit defined by FAO and WHO. The average concentrations of Fe and Mn in all sub-districts crossed the recommendations, whereas average concentrations of Zn, Ni, Cd, and Pb were within the recommendations. Regardless of sampling site, target hazard quotients (THQ) of more than 1 contributed by Fe confirmed higher level of hazard index (HI), indicating potential human health risk. Fortunately, no heavy metal or their additive effect found to offer lifetime potency of carcinogenesis upon consumption of these shrimps. Therefore, probabilistic non-carcinogenic human health risk from Fe contamination necessitates stringent monitoring and controlling of this metal from different sources to farms.

The study was carried out to obtain information on the present status and trend of finfish diversity of the Old Brahmaputra river, Bangladesh. Samples were collected directly from a professional fishing boat caught by different nets, traps and hooks from January 2019 to December 2019. Together with 4 exotic species, a total of 49 species under 6 families were recorded. Though a biodiversity index of 3.65854 and a dominance index of 0.030929 represent the richness of ichthyo-diversity within the river, Synbranchiformes and Tetraodontiformes were not reported throughout the study period. Linear regression analysis showed a positive correlation between water height of the river and monthly abundance of the species found. Catch composition of catfishes and snakeheads slumped while barbs showed triumph over previous findings. A majority of fish recorded were within the least concern category according to IUCN (2015) but portions also belonged to critically endangered, endangered, and vulnerable categories as well. Therefore, conservation measures must be infixed in the Old Brahmaputra river to hold the fish diversity in a sustainable state.