Effect of dietary supplementation with seaweed on growth and nutritional quality of Nile tilapia

Abstract

Feed is a major component of production in aquaculture, accounting for about 80% of production cost. High quality feeds are a prerequisite to healthy and nutritious fish. Aqua feeds are expensive owing to the fact that fish oil and fish meals are the main sources of lipid and protein components respectively. Having alternative cheap sources of lipids in the feeds is therefore important. The brown seaweed (Sargassum portieranum) that is locally available is known to be rich in omega 3 fatty acids. The aim of this study was to determine the effects of brown seaweed supplementation on the nutritional quality and growth performance of Nile tilapia (Oreochromis niloticus).

A total of 180 male Nile tilapia fingerlings were divided into three experimental groups in triplicates. The fish were assigned to one of the three treatment diets: 0% (control diet), 5% and 10% inclusion of the brown seaweed and fed for 12 weeks. The weight and length (head to tail) of the fish was measured every two weeks to determine the growth performance. At the end of the experiment the fish muscle protein, lipid and mineral content were determined using AOAC methods.

Seaweed supplementation significantly (P<0.05) improved the body weight, length, survival and the specific growth rate of the fish, with the 10% inclusion showing higher performance than the 5%. The protein, mineral and lipid contents of the fish muscle were also significantly affected by the seaweed supplementation. Fish fed with the 10% diet had the highest total lipid content at 0.93% compared to 0.78% in the fish fed on the control diet. The protein content in the fish muscle was not significantly affected (P<0.05) by inclusion of seaweed in the feed. Overall, the results indicated improved growth performance and nutritional quality of tilapia fish when the feed were supplemented with either 5% or 10% of the brown seaweed. Thus, including the brown seaweed meal in the diet of tilapia fish could offer an effective means to boast production in aquaculture.