The Selenium Supplementation Dietary Effect on the Nutritional Value and Immune Response of the Pacific White Shrimp Litopenaeus vannamei (Boone, 1931)

While Selenium (Se) deficiency results in the corruption of antioxidants’ efficacy, any increase in its level causes toxicity and subsequently weakens growth rate and immune responses. Thus, it is important to assess the appropriate levels of Se supplementation in the diet, either inorganic or organic form, to precisely comprehend its impact on the growth and health of experimental samples. Samples of Litopenaeus vannamei were fed diets supplemented with different levels of organic and inorganic selenium (seleno-L methionine and sodium selenate). For 90 days, shrimps were fed on a diet formulated as pellets mixed with 0.3, 0.4 and 0.5 mg of organic Se and represented mainly by selenomethionine, and the same concentrations were considered for the inorganic selenium (sodium selenite). The effect of the formulated diet on the proximate composition of basic biochemical constituents of the cultured Litopenaeus vannamei was evaluated. After the feeding trial, shrimps were used for protein and fat composition, amino acids and fatty acids analysis. Detection of vibrio count in hepatopancreas and haemolymph count were also measured. The results revealed that the Se type and concentrations affecting amino acid ratio indicate the priority of inorganic Se over organic Se and 0.3mg/ kg concentration over the higher ones (0.4 and 0.5mg/ kg). The highest recorded fatty acids % were associated with organic Se dietary (oleinic acid and elaidic acid) (24.1% and 14.9, respectively), which significantly increased at 0.5mg/ kg organic Se (31.2% and 17.9% respectively). Generally, the organic Se scored higher fatty acid ratios than basic and inorganic Se diets, especially at 0.4mg/ kg Se. L. vannamei fed Se in its diets recorded lower bacteraemia than control ones; this was mainly observed in those fed 0.4 and 0.5mg/ kg organic Se (P< 0.05). Furthermore, the incorporation of organic selenium (OS) in the diet stimulated the proliferation rate of total haemocyte cells (THCs) in the studied species.