The effects of dietary supplmented Ulva lactuca on the feeding preference and growth of sea cucumber Apostichopus japonicus (Selenka, 1867)

Abstract

This study was to evaluate the attractiveness and growth performance of the sea cucumber Apostichopus japonicus supplemented with Ulva lactuca. Four diets containing different percentages of U. lactuca powder and fermented soybean meal (Biomax), were formulated and referred as UV0 (0 % U. lactuca and 24.9 % Biomax, control), UV5 (5 % U. lactuca and 24.9 % Biomax), UV10 (10 % U. lactuca and 24.9 % Biomax) and BU (40 % U. lactuca and 38 % Biomax). All experimental sea cucumber survived after the 7-day attraction and 12-week feeding experiments. Regarding relative attractiveness, our results showed that BU was the most preferred (61.90±9.52 %) among four diets. In the feeding trial, the weight gain (WG) of individuals fed with BU diet (138.86±1.73 %) was significantly higher than that of individuals fed with the other diets (P < 0.05). No significant difference in WG (P > 0.05) was found between individuals fed with UV5 and UV10 (122.32 ± 4.48 and 123.26 ± 5.80 %, respectively), but both these groups exhibited significant (P < 0.05) enhancement compared to individuals fed with UV0 (86.21±4.31 %). Moreover, individuals fed with UV5, UV10 and BU showed significantly (P < 0.05) higher specific growth rate (SGR) (0.95±0.02, 0.96±0.03 and 1.04±0.01 %, respectively), lower feed conversion rate (FCR) (0.92±0.04, 0.90±0.08 and 0.84±0.05, respectively) and higher feed intake (FI) (44.99±1.26, 44.05±2.16 and 47.48±2.85, respectively) than those fed with UV0 which had 0.74±0.03 %, 1.16±0.04 and 39.76±1.61 for SGR, FCR and FI, respectively. Overall, our data suggested that dietary addition of Ulva lactuca could have benefit for sea cucumber aquaculture.