The effect of substituting Undaria pinnatifida in formulated feeds with Sargassum horneri on growth and body composition of juvenile abalone (Haliotis discus, Reeve 1846)

Dietary substitution effect of Undaria pinnatifida with Sargassum horneri on growth and chemical composition of juvenile abalone was investigated. A total of 1260 juvenile abalone were randomly distributed in 21, 100-L net cages (60 per cage). Six formulated diets were prepared. Twenty percent U. pinnatifida powder was included in the control (SH0) diet. The U. pinnatifida component of the experimental diets was substituted with S. horneri at the rates of 20, 40, 60, 80, and 100%, referred to as the SH20, SH40, SH60, SH80, and SH100 diets, respectively. Finally, dry U. pinnatifida was prepared to compare effect of the formulated diet on abalone. Abalone were fed with one of the experimental diets once a day for 16weeks. Water stability of nutrient content in all formulated diets was changed with time. Survival of abalone fed all formulated diets was higher than that of abalone fed the U. pinnatifida. Abalone fed the SH0, SH20, SH40, SH60, and SH80 diets achieved greater weight gain and specific growth rate (SGR) than those of abalone fed the SH100 diet and U. pinnatifida. The greatest weight gain and SGR were obtained in abalone fed the SH60 diet. The proximate composition of the soft body of abalone, except for crude protein, was not affected by the experimental diets. In conclusion, U. pinnatifida up to 80% could be substituted with S. horneri when 20% U. pinnatifida was included in formulated abalone feed. The SH60 diet achieved the best growth performance of abalone.