Effect of dietary organic selenium on survival, growth, antioxidation, immunity and gene expressions of selenoproteins in abalone Haliotis discus hannai.

No studies have been focused on the inclusion of organic selenium in formulated feed of abalone when organic minerals are accepted by aquaculture feed industry. This experiment evaluated the effect of organic selenium on the growth, antioxidation, immunity and gene expressions of selenoproteins in abalone. Graded levels of organic selenium were included to the basal diet at 0.00, 0.15, 0.30 and 0.60 ppm providing 157.83, 322.51, 437.59 and 596.59 ug/kg of selenium in the diet. Accordingly, the diets were named as Se‐0.00, Se‐0.15, Se‐0.30 and Se‐0.60 respectively. Results had shown that survival rate, weight gain rate and shell length increase rate were lowest for Se‐0.60 group (p < 0.05). The concentration of selenium in the whole body generally increased with increasing level of dietary organic selenium (p < 0.05). The enzyme activities related to antioxidation increased initially with low levels of dietary selenium and decreased with higher levels, with the highest value in Se‐0.30 group (p < 0.05). The enzyme activities of immunity increased with the addition of dietary selenium. With the increase of dietary selenium, Myostain expression decreased initially and increased afterwards, with lowest value for Se‐0.30 group (p < 0.05). However, the expressions of other genes related to growth, antioxidation and selenoproteins firstly increased and then decreased, with the highest value recorded for Se‐0.15 group. In conclusion, the inclusion rate of 0.15 – 0.30 ppm Se in diet could promote growth, antioxidation, immunity and gene expressions of selenoproteins in abalone; however, excess selenium with 0.60 ppm inclusion lever in diet had toxic effects. [ABSTRACT FROM AUTHOR]