Effect of dietary protein, vitamin E, and vitamin C levels on the growth and gonad development of hybrid male abalone (Haliotis fulgens ♂×H. discus hannai ♀) by the orthogonal array design

A natural feed of fresh seaweed and sixteen diets designed by L16 (43) orthogonal array were formulated to contain differentlevels of protein (200, 250 g, 300, 350 g/kg), α- Vitamin E (VE) (0, 0.1, 0.3, 0.5 g/kg) and Vitamin E (VC) (0, 0.5, 1, 1.5 g/kg) to evaluate the effects of dietary protein, VE, VC and their combination on growth and gonadal development of hybrid male abalone ( Haliotis fulgens ♂×H. discus hannai ♀ ). Each diet was randomly assigned to triplicate groups of 18 abalones (34.27±2.93 g) that were stocked in sea cages for eight weeks. Results showed that the maximum weight gain (WG) and specific growth rate (SGR) were obtained in hybrid male abalone fed D10 diets. The highest gonad somatic index (GSI) value was found in the D14 diet. Moreover, the ANOVA results showed that only dietary protein could significantly affect the GSI of hybrid male abalones ( P < 0.05). The mRNA expression of vasa in the testis of D14 abalone was the lowest. Abalones fed the D14 diet had higher testosterone level and sperm in testis than those fed other diets. In conclusion, protein of 300 g/kg, VE of 0.1 g/kg and VC of 1.5 g/kg (D10) and protein of 350 g/kg, VE of 0.1 g/kg and VC of 1 g/kg (D14) might be the optimal combinations in the diet for growth and gonadal development of hybrid male abalones respectively.