Sea lettuce (Ulva lactuca) meal combined with soybean meal in a low fishmeal diet enhanced the growth and feed intake of cultured golden rabbitfish (Siganus guttatus) during the nursery stage

Abstract

A preliminary feeding trial was conducted to evaluate the effect of utilizing a high level of sea lettuce (SL), Ulva lactuca meal, as a dietary ingredient on the growth and biochemical composition of the golden rabbitfish, Siganus guttatus. Two treatments included one diet containing high SL meal combined with soybean (PP) and another diet that used fish meal as the primary protein source (FM). Golden rabbitfish were stocked into 8 of 120 L fiberglass tanks with a density of 20 fish/tank and fed for 15 weeks. The weight gain of the fish-fed PP diet was 453% higher than those provided with FM (343%). Similarly, the SGR of fish fed the PP diet was higher (1.40 %/d) compared to the PF diet (1.22 %/d). The FCR of the FM diet was lower (1.3) compared to the PP diet (1.6). Fish fed the FM diet contained a higher ash content than those fed the PP diet (14.9 vs 10.1%). Crude protein content in body fish was relatively similar for both diets. Including sea lettuce meal at 30% combined with a high level of soybean meal in a low fishmeal diet, they produced better growth performances of rabbitfish during the nursery stage.