Effect of heated and unheated fish silage as a protein source in diets forabalone Haliotis fulgens

Both unheated (US) and heated (HS) fish silage were evaluated as sole dieta ry protein sources in an artificial diet for the culture of juvenile abalon e Haliotis fulgens. The fish silage was heated to reduce the level of hydro lysis and thereby increase the availability of nutrients. After 140 d of cu lture, growth rates of abalone fed the US- and MS-containing diets were 16. 4 and 19.8 mu m/d and were not significantly different despite greater leac hing of protein and carbohydrate in the US-containing diet. Growth rates ac hieved with the US- and MS-containing diets were significantly lower than t hat achieved by feeding a commercially available diet used as a reference d iet. Abalone that were fed the US- and MS-containing diets were then switch ed to a diet in which two-thirds of the total amount of silage was replaced with fishmeal. At the termination of the experiment, day 217, the abalone originally fed the US and HS diets had composite growth rates of 24.3 and 2 3.5 mu m/d, while abalone that continued to be fed the commercial diet had a growth rate of 18.6 mu m/d. Stability of the dry matter of the diets was not related to the level of protein leaching. Fish meal outperforms fish si lage as a dietary protein source for abalone. However, growth rates achieve d still fall short of that needed to achieve a market size product within a 2-yr period of growth.