Nanoselenium versus bulk selenium as a dietary supplement: Effects on growth, feed efficiency, intestinal histology, haemato‐biochemical and oxidative stress biomarkers in Nile tilapia ( Oreochromis niloticus Linnaeus, 1758) fingerlings

Abstract

Five isonitrogenous (30% crude protein) diets were formulated to contain two forms of selenium (Se): convention Se named Bulk‐Se or Se nanoparticles (Nano‐Se), both forms of Se supplemented at two levels 0.4 and 0.8 mg kg−1 diet compared to the control diet without addition for a period of 84 days. Nile tilapia, Oreochromis niloticus, fingerlings (5.0 ± 0.2 g) fed tested diets in triplicates at a rate of 5% of their total biomass three times a day for 84 days. The results showed that the best growth performance and amylase and lipase enzymes activity (p ≤ 0.05) were observed in fish fed 0.4 or 0.8 mg kg−1 Nano‐Se diet. In anterior intestine, fish fed 0.8 mg kg−1 Nano‐Se recorded the highest level (p ≤ 0.05) of villi height and width and goblet cell number. The highest values mucosal‐to‐serosal amplification ratio (MSR) and absorption area of villous were recorded in fish fed 0.4 mg kg−1 Nano‐Se. Fish fed 0.8 mg kg−1 Nano‐Se recorded the highest value (p ≤ 0.05) of villi height, villi width, MSR and crypt thickness, while fish fed the control diet recorded the lowest level one in posterior intestine. In addition, fish fed 0.8 mg kg−1 Nano‐Se noted the best values of haemoglobin, haematocrit, red blood cells and white blood cell count. Alanine and aspartate aminotransferases were lower, while total serum protein, albumin and globulin contents were significantly higher in fish fed diet contained 0.4 or 0.8 mg kg−1 Nano‐Se compared to Bulk‐Se and control diet. The highest significant values of superoxide dismutase, catalase, glutathione peroxidase, glutathione, glutathione‐S‐transferase and glutathione reductase activity accompanied with the lowest MDA value recorded of fish fed diet supplemented with 0.8 mg kg−1 Nano‐Se. The results indicated that the inclusion of Nano‐Se at 0.8 mg kg−1 was the recommended source and level of Se to improve performance, efficiency of nutrient, digestive enzyme activity and absorption surface of intestine, haemato‐biochemical parameters and oxidative stress responses of Nile tilapia compared with other treatments.

Selenium Nanoparticles as a Natural Antioxidant and Metabolic Regulator in Aquaculture: A Review

“…Accordingly, the beneficial bacteria can perform more effectively in digesting the nutrients through the secretion of digestive enzymes. The enhancement in the growth performance of fish is also explained by Ibrahim et al [5], who indicated that Nile tilapia-fed dietary Se nanoparticles (0.4-0.8 mg/kg) showed enhanced growth performance and feed efficiency. The authors also confirmed that Se nanoparticles caused a positive impact on the intestinal histomorphological features.…”

“…Aquatic animals suffer from various biotic and abiotic stressors that may occur during the farming season [76]. Nutritionally balanced aquafeed is the main key factor that helps counteract these stressors leading to high productivity and well-being [5]. Microelements, including Se, is another vital strategy to guarantee the balance of the nutritional value of aquafeed [1].…”

“…Indeed, stressful conditions are involved in the imbalance of the physiological and metabolic function of a fish's entire body [78]. Along with well management practices, high-quality feeds containing macro and micronutrients are recommended to enable fish to perform well and resist biotic and abiotic stressors [5]. In this context, red sea bream fed Se nanoparticles (1-2 mg/kg) showed high resistance against low salinity stress [68].…”

“…Accordingly, nanominerals can beneficially affect animals' metabolic, physiological, and biological functions [4]. Selenium (Se) particles are one of the microelements involved in various tasks in the entire body of aquatic animals [1,5]. The targeting role of Se is to protect cells from oxidation through the formation of antioxidative defenses [6].…”

“…Se nanoparticles are well investigated with high potential as a growth promotor, antioxidative, and immunostimulant agent in aquaculture [11,12]. Multiple studies reported the necessity of including Se nanoparticles for enhancing the growth performance, physiological, and health status in aquatic animals [5,13,14]. Due to the low margin between the benefits and the toxicity, Se nanoparticles have to be included in aquafeed based on a dose-specific manner.…”