Dietary inclusion of Acti-Meal improves growth and feed utilisation of greenlip abalone (Haliotis laevigata)

Acti-Meal is a co-product of the wine industry, consisting of a steam distilled, milled and dried grape marc meal rich in carbohydrates (55–65%). In this 90-day study, growth and feed utilisation of juvenile (1.82 g) greenlip abalone (Haliotis laevigata) fed diets containing graded dietary inclusion levels of Acti-Meal (0 basal, 5, 10, 15 and 20%) were examined. Four replicates were allocated per treatment with 15 abalone per tank and abalone were fed to excess daily. All experimental diets were formulated to contain 35% crude protein, 5% crude lipid and 17.5 MJ kg⁻¹ gross energy. In addition, a commercial diet was also fed to abalone and compared with the 0% diet. Growth and feed utilisation of greenlip abalone fed the commercial diet and the 0% basal diet were similar. Greenlip abalone fed any Acti-Meal inclusion level (5, 10, 15 and 20%) exhibited significantly superior growth to abalone fed the 0% basal diet. Notably, in comparison to the basal diet, specific growth rate and biomass gain were improved by 5 to 6% and 10 to 12% respectively. The improvements were achieved despite greenlip abalone consuming significantly less feed (~9%) when fed the Acti-Meal diets. Greenlip abalone fed diets with Acti-Meal also exhibited superior apparent feed conversion ratios compared to those fed the 0% basal diet, on average FCRs were reduced by 13%. We recommend dietary inclusions of up to 20% Acti-Meal to improve greenlip abalone growth. We also recommend an on-farm growth trial to validate this product.