Comparative analysis of biometrical and reproductive indices, proximate composition, and hemato-biochemical variables of cuchia eel Monopterus cuchia (Hamilton, 1822) from six different localities of Bangladesh.

Cuchia eel (Monopterus cuchia) is among the most sought-after freshwater fish, owing to its exceptional nutritional profile and high consumer demand. The current research aimed to establish baseline data by comparing the proximate composition, hematological, and plasma biochemical indices of Cuchia eel populations across six different geographical locations in Bangladesh: Bogra, Haluaghat, Jamalpur, Moktagacha, Sylhet, and Tangail. By examining these parameters, we aim to gain valuable insights into the nutritional benefits, physiological responses, and potential adaptations of this species to varying environments. The statistical analysis revealed no significant (P > 0.05) variances in the whole-body proximate composition of the fish captured from distinct areas. However, it was observed that different geographical regions had remarkable impacts on the variations of the majority of the hematological parameters, except for some cases. Additionally, there was a notable (P < 0.05) increase or decrease in most of the serum biochemical contents in certain localities as compared to others in this study. Light microscopic examination of Cuchia eel blood smears exhibited lower numbers but larger sizes of RBCs. The findings of this study lead to the conclusion that different localities had significant impacts on the hematology and blood biochemical indices of Cuchia eel, even though the whole-body proximate composition showed no significant variations. This research contributes to a deeper understanding of the physiological aspects of Cuchia eel.

Dietary Administration of Engineered Nano-selenium and Vitamin C Ameliorates Immune Response, Nutritional Physiology, Oxidative Stress, and Resistance Against Aeromonas hydrophila in Nile Tilapia (Oreochromis niloticus).

Functional trace elements and vitamins can boost immunity and anti-oxidative response in aquatic animals with effects on nutritional physiology. Nano-selenium (nano-Se) and vitamin C (VC) have been used as immunomodulators and antioxidants in fish feed. The present work was performed to determine the protective effects of diets supplemented with different combinations of nano-Se and VC on Nile tilapia (Oreochromis niloticus). Triplicate groups of 20 fish/tank (13.87 ± 0.10 g) were reared and fed with basal diet (control-T1) (without supplementation of nano-Se and VC) and three experimental diets as T2, T3, and T4 (100, 200, and 300 mg/kg VC respectively) with a pre-determined dose of nano-Se (1.0 mg/kg) for 90 days. Different immune indices, haemato-biochemical, and antioxidant activities were measured at the end of the first, second, and third months of feeding. The findings depicted that significantly (p < 0.05) higher growth was observed in T4. Red blood cells, white blood cells, and haemoglobin were found significantly (p < 0.05) higher in T4 for the third month. Serum biochemical-immunological indices (alkaline phosphatase, glucose, cholesterol, lysozyme, myeloperoxidase, total protein, albumin and globulin) followed the same trend. Furthermore, antioxidant assays such as catalase, superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and malondialdehyde were significantly (p < 0.05) improved in T4 for the third month. Significantly (p < 0.05) least cumulative mortality against Aeromonas hydrophila was obtained in the fish-fed diets incorporated with nano-Se and VC. Therefore, dietary supplementation with nano-Se and VC is noteworthy for improving growth, serum biochemical status, immune response, antioxidant status, and disease resistance.

Nano-selenium Supplementation to Ameliorate Nutrition Physiology, Immune Response, Antioxidant System and Disease Resistance Against Aeromonas hydrophila in Monosex Nile Tilapia (Oreochromis niloticus).

In the present work, a total 180 monosex male Nile tilapia fingerlings (15.73 ± 0.05 g) were stocked in 150-l FRP tanks categorised into four diet groups with triplicate each and fed with dietary nano-selenium-supplemented diets at different concentration (T1-0, T2-0.5, T3-1.0 and T4-2.0 mg/kg of feed) for 90 days and different nutrition physiological parameters (feed utilization, haematology, serum biochemistry), immune response and antioxidant were analysed during pre- and post-challenge against Aeromonas hydrophila. The study results depicted that significantly (p < 0.05) better growth and feed utilization (absolute weight gain, specific growth rate, average daily gain, protein efficiency ratio, food conversion ratio) found in fish fed diet supplemented with 1 mg/kg of nano-Se. Significantly (p < 0.05) improved haematological (red blood cells, haemoglobin, white blood cells, platelets) and serum biochemical parameters (alanine aminotransferase, aspartate aminotransferase, glucose, cholesterol, triglycerides) observed in the same diet group. The same trend was followed by immune parameters (nitro blue tetrazolium, lysozyme activity, myeloperoxidase, total immunoglobulin). Also observed the statistically (p < 0.05) improved antioxidant activities (catalase, superoxide dismutase, glutathione peroxides, glutathione reductase, glutathione S-transferase, malondialdehyde, total antioxidant capacity) in the same diet group. Relative percent survival after the fishes challenged with A. hydrophila was significantly (p < 0.05) differed. The findings suggested that supplementation of 1 mg/kg of dietary nano-Se could able to ameliorate nutrition physiology, immunity, antioxidant activity and disease resistance in tilapia and proved that it may be one of the best element for fish farmers to increase the production in an economically feasible way.