Effects of Different Dietary Protein Levels for Maximum Growth of Rabbitfish (Siganus guttatus Bloch) Reared in Floating Netcages

Abstract

A 60-day feeding trial was conducted in 12 units of cages measuring 1.0 x 1.0 x 1.5 m installed at South Sea AquaVenture Fishcage Project, Tiniguiban Cove, Puerto Princesa City, Palawan to determine the growth and survival rates of wild rabbitfish (Siganus guttatus Bloch) fed with formulated diets with protein levels ranging from 20% to 30% with 5% interval. "Lumut" (Chaetomorpha spp.) was also used as feed to serve as the control. Rabbitfish with a mean initial body weight ranging from 5.73+0.30g to 6.05+0.14g and mean total length from 8.11+0.18cm to 8.58+0.34cm., were randomly distributed at a stocking density of 20pcs/m3. The stocks were fed at 10% body weight thrice daily.

The fish fed with 20 and 30% crude protein showed significantly higher FCR, final weight, and biomass than those fed with "lumut". Moreover, the FCE of rabbitfish fed with formulated diets was highly significant than those fed with "lumut". There were no significant differences in terms of K, weight gain, SGR and survival among treatments.

The better biomass, FCR and FCE obtained from treatments with formulated feeds suggest improved growth response of rabbitfish with high protein diet. It is recommended that a longer culture period and higher protein level be used on further study for optimum fish growth.