development of compounded feed for grow-out of abalone Haliotis squamata
Abalone is one type of marine mollusks that has a good prospect in terms of price, market share and simple culture technique. Technology of mass seed production of abalone Haliotis squamata has been developed successfully. In addition to seeds, the availability of appropriate feed largely determines the success of abalone aquaculture development. In nature habitat, abalone eat fresh food in the form of fresh macro algae. However, abalone can also accept compounded feed properly. Therefore, the aims of this research were to know growth response of abalone fed compounded feed based on seaweed meal and to find out an appropriate proportion of seaweed meal in compounded feed for growth of abalone.
Two feeding trials on applications of compounded feed had been conducted in the Institute for Mariculture Research and Development, Gondol-Bali. For the first feeding trial, 4 compounded feeds (30,2% protein; 6,2% lipid) with different combinations of seaweed meal were prepared as dry pellet. Juvenile abalone with an average weight of 3.07 ± 1.11 g with 2.79 ± 0,27 cm shell length were reared in the concrete tank of 2 x 0.5 x 0.5 m3 with a density of 400 abalone/tank. Tanks were equipped with flow-through sea water system. Abalone fed experimental feed 2 times a day for 180 days. The experiment was designed with a completely randomized design (CRD), with 5 treatments and 3 replications for each treatment. In the second feeding trial, 3 experimental feeds (25.0% protein; 6,6% lipid) with the different proportions of seaweed meal of Ulva sp., Gracilaria sp., and Sargasum sp. were prepared as dry "block flake". The control feed for both feeding trials was fresh Gracilaria sp. from pond culture. Juvenile abalone of 5.30 ± 1.07 g body weight and 3.35 ± 0.29 cm shell length were stocked at density of 388 abalone/tank. Tank system was the same as for the first feeding trial. Abalone was fed experimental feed twice a day for 168 days. The experiment was designed with CRD with 4 treatments and 4 replications for each treatment.
The results of the first feeding trial showed that the diets prepared from mixture of Gracilaria sp. with Ulva sp. meal or a mixture of Gracilaria sp. from pond culture with Sargassum sp. meal provided good growth responses of abalone H. squamata. The results of the second feeding trial showed that the growth of abalone fed compounded feed did not differ significantly, but the feed with the proportion of Ulva sp. meal 35% tend to give better growth. For both feeding trial survival was the same and the best growth was obtained from the abalone fed fresh Gracilaria sp. The protein content of abalone meat fed compounded feed was significantly higher compared to the control.