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Aquaculture, as a strategic and developmental industry, plays an important role in ensuring food security and economic stability within countries. This crucial sector faces various influences, including infectious and nutritional diseases. Certain minerals function as essential nutrients, playing a main role in processes across all aquatic animals when present in appropriate dietary proportions. Studies showed that some heavy metals serve as a catalyst for various biological functions, including the maintenance of colloidal systems, acid-base balance, bone formation, and the regulation of fundamental natural elements such as vitamins, hormones, and minerals. Fish acquire essential elements crucial for their well-being through both diet and water sources. Adequate levels of essential elements, such as iron, zinc, copper, cobalt, manganese, and selenium, in the diet contribute to enhanced growth, increased survival rates, improved disease resistance, and heightened specific immunity in fish. When incorporated in appropriate quantities, these elements play a pivotal role in disease prevention, fostering the production of high-quality fish, minimizing economic losses, and solidifying aquaculture as a robust and profitable industry. This article aims to delve into the immunological effects induced by metal elements, specifically copper (Cu), cobalt (Co), manganese (Mn), zinc (Zn), and selenium (Se), in diverse fish species. The objective is to underscore the significance of this exploration, paving the way for the development of more potent immune supplements in the future. These supplements have the potential to improve growth, fortify immune responses, and enhance resilience against diseases in various fish species. [ABSTRACT FROM AUTHOR]

The current research was conducted to examine the effect of Artemisia dracunculus (AD) extract on growth performance, haemato‐immunological, biochemical parameters, and mucosal immunity in the rainbow trout (Oncorhynchus mykiss). The fish were fed with a diet supplemented with 0 (control), 1%, 2% and 3% AD for 8 weeks. The findings indicated that in all groups fed AD, especially at the 2% level, the growth parameters and survival rate significantly increased compared with the control group. Blood biochemical parameters, creatinine, glucose, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and triglyceride were decreased significantly in AD‐treated groups. Total serum protein (TSP) levels, lysozyme (LYZ) and respiratory burst activities (RBA) were increased in the fish fed with AD. TSP levels, ALP and protease (PA) activities in the mucus were significantly increased following fish fed with AD. Increased in the total immunoglobulins (Ig) and superoxide dismutase (SOD) activity were observed in the fish fed with 3% AD. Fish fed with 2% AD showed the highest levels of alternative complement (ACH50) significantly. In addition, the mucus bactericidal activity was significantly increased in some treatments fed AD diet against Lactococcus garvieae and Aeromonas hydrophila. After infection with Yersinia ruckeri, there was a reduction in the mortality rate in the AD‐fed groups compared with the control group. Thus, it can be concluded that diets supplemented with AD can significantly impact diverse physiological parameters in fish, improving their growth performance, blood biochemical parameters and immune response. [ABSTRACT FROM AUTHOR]

The toxicological effects of three commonly used pesticides in Iran on the fries of Caspian kutum (Rutilus kutum, Kamensky, 1901) were investigated through determining 50.00% lethal concentration (LC50) 96-hr and cholinesterase (ChE) inhibition. The LC50 96-hr of carbaryl, glyphosate, and malathion were equal to 11.69, 6.64, and 0.97 mg L-1, respectively, that were considered as harmful (10.00 - 100 mg L-1), toxic (1.00 - 10.00 mg L-1) and very toxic (< 1.00 mg L-1) compounds for this species. The exposure of fries to sub-lethal concentrations of the pesticides over 15 days indicated that the average of ChE activity in the head and trunk were 1086.89 ± 124.34 and 627.36 ± 99.60 mU min-1 per mg protein, respectively, with a significant difference relative to each other. There was a significant difference between fry exposed to all three pesticides and the control group in cholinesterase inhibition. The fries exposed to carbaryl (890.12 ± 28.08 mU min-1 per mg protein) and glyphosate (891.77 ± 31.61 mU min-1 per mg protein) showed lower ChE inhibition than those exposed to malathion (790.00 ± 58.14 mU min-1 per mg protein). [ABSTRACT FROM AUTHOR]

A six‐week feeding trial was conducted to determine the effect of butyric acid (BA) inclusion in diet on performance of Barramundi (Lates calcarifer). Fish (12.0 ± 0.2 g) were fed with four experimental diets contained 0.0 (control), 2.5, 5.0 and 10.0 g BA/kg in triplicate. Fish fed on 5 and 10 g BA/kg diets had higher growth and total alkaline protease and lipase activities than the other treatments. Fillet protein content in BA‐supplemented groups was higher than the control. Liver catalase activity was highest in 2.5 g BA/kg group compared with the other groups. The values of liver superoxide dismutase activity and serum total protein concentration in 5 and 10 g BA/kg treatments were higher than those in the control (p <.05). Moreover, the highest and the lowest levels of serum lysozyme activity were noticed in the 10 g BA/kg and the control groups, respectively (p <.05). Also, the highest respiratory burst activity was observed in fish fed 5 g BA/kg feed. Supplementing diet with 2.5 or 5 g BA/kg resulted in higher serum haemolytic activity in fish compared with the other groups. The number of red and white blood cells increased in fish fed BA‐supplemented diets compared with the control (p <.05). In conclusion, the results of this study showed inclusion of BA at 5 g/kg diet in L. calcarifer juveniles improved growth and upgraded the general health condition by enhancing fish antioxidant enzyme activities and haemato‐immunological responses. [ABSTRACT FROM AUTHOR]