Seaweed Gracilariopsis heteroclada , formulated flaked diet, and a combination of both as feed for the abalone Haliotis asinina : effect on growth and survival

This paper compares the effect of feeding the abalone Haliotis asinina with seaweed (SW), formulated (FD), and mixed (SW+FD) diets. The feeding experiment, in six replicates, was conducted in a tank facility and lasted for 10 months. At the end of the experiment, abalone fed mixed diets had significantly the highest mean shell length and body weight (45.90±0.19 mm, 22.82±0.31 g), followed by those fed seaweeds (43.47±0.17 mm, 18.25±0.26 g), and lastly, by those fed formulated diets (41.78±0.18 mm, 15.76±0.22 g). Mean growth rates were significantly higher in abalone fed mixed diets at 1.48±0.03 mm and 1.69±0.04 g mo −1 than those fed seaweeds (1.26±0.03 mm, 1.27±0.06 g mo −1 ) or formulated diet (1.06±0.09 mm, 1.00±0.11 g mo −1 ). Survival was consistent 1 month from the start of culture until harvest—highest in abalone fed mixed diets (78.81±2.48%), followed by those fed seaweeds (70.12±4.07%), and lastly formulated diet (64.53±4.61%). Moreover, feed conversion ratios (FCR) were significantly lower in abalone fed mixed diets (15.48±0.69) and formulated diet (18.07±3.50) compared with those fed seaweeds (41.31±2.36). The body weight to shell length ratios (BW:SL), which were the same in all treatments at the start of the experiment (0.19 g mm −1 ), increased to 0.51, 0.44, and 0.38 in abalone fed mixed diets, seaweeds, and formulated diet, respectively. Based on the results of this experiment, giving abalone a mix of formulated and natural diets is the best feeding regime. The importance of a balanced and more nutritional diet on the well-being of the abalone was observed in this study.