Suitability of three red macroalgae as a feed for the abalone Haliotis tuberculata coccinea Reeve

A 60-day feeding trial was conducted to assess the suitability of three red algae, Hynea spinella, Hynea musciformis and Gracilaria cornea, as potential feed for the culture of juvenile abalone, Haliotis tuberculata coccinea R. Seaweeds were reared in a biofiltration unit with fishpond waste water effluents. The three algal species were found to contain high protein contents which would be related to its production under the high nitrogen culture conditions of the biofilter system. Protein and carbohydrate contents were highest in H. musciformis and lowest in G. cornea. Survival rates of juvenile abalone were very good, regardless of the algae fed. Feed intake of H. spinella was highest, followed by H. musciformis. Growth rates of abalone were within the range obtained under commercial conditions, final shell length and weight being significantly highest in animals fed H. spinella and lowest in those fed G. cornea. Feeding G. cornea lead to the lowest growth performance due to the lowest feed intake, whereas feed conversion ratios were significantly highest for H. musciformis and protein efficiency ratios were higher for both H. spinella and G. cornea. This study suggested the good potential of any of the three red seaweeds tested—successfully produced by the biofilter system, their nutritional composition being similar to other macroalgae used as feed for abalone and matching the abalone protein and lipid requirements—hence promoting growth and survival. Nevertheless, the biofilter produced macroalgae H. spinella showed the highest dietary value for juvenile of H. tuberculata coccinea.