Effects of different levels of dietary manganese on growth, blood parameters, immunity indices, blood biochemical and tissue accumulation of elements in young beluga, Huso huso

Manganese (Mn), functioning as a microelement, serves as a crucial cofactor in numerous enzyme systems. This element is indispensable for regulating the nervous system, bone growth, and reproduction, while also playing a pivotal role in carbohydrate metabolism. This research endeavours to establish the optimal dietary Mn range for young beluga, Huso huso. A cohort of ۱۸۰ young beluga, with an average initial weight of ۲۶۶ ± ۳.۰۵ g, underwent a two-week acclimatization period to adapt to their environment. The fish were systematically allocated into ۶ treatments, each with three replications, encompassing concentrations of ۵ (Mn۱), ۱۰ (Mn۲), ۱۵ (Mn۳), ۲۰ (Mn۴), and ۲۵ (Mn۵) mg of Mn sulphate monohydrate (MnSO۴, H۲O) per kg of diet. A control treatment (Mn۰), devoid of MnSO۴ supplementation, was also included. The feeding regimen involved ۳ time-daily feedings, constituting ۱.۸% of the biomass, sustained over two months. Biometric growth indices at the end of each month revealed no statistically significant differences across diverse treatments (p > ۰.۰۵), but the maximum values of these indices were observed in the control and Mn۳ treatments, respectively. However, the number of red blood cells (RBCs) and white blood cells (WBC), as well as haemoglobin (Hb) levels, exhibited significant differences (p < ۰.۰۵). Additionally, significant variations were observed in the plasma triglyceride and cholesterol levels (p < ۰.۰۵). Mn۲ treatment demonstrated the highest significant activity of lysozyme and total immunoglobulin (Total Ig) levels (p < ۰.۰۵). Conversely, immunoglobulin M (IgM) levels and complements activity (C۳ and C۴) remained non-significant across Mn۰, Mn۱, and Mn۲ treatments (p > ۰.۰۵). Despite the noteworthy level of tissue Mn aggregation (p < ۰.۰۵), no significant differences were noted in the tissue cumulation of Ca, Fe, and P elements within muscle, blood, cartilage, and liver (p > ۰.۰۵). Based on the obtained results, it is concluded that the optimal supplementation level of MnSO۴ required for young H. huso falls within the range of ۱۰-۱۵ mg kg-۱ of diet.

کلیدواژه ها:

Beluga ، Huso huso ، Diet ، MnSO۴ ، Immunity ، Biochemical ، Element accumulation