Using Seaweed Sargassum illicifolium in Shrimp Litopenaeus vannameii Aquaculture

Abstract

The marine brown seaweed Sargassum illicifolium is abundant along the Iranian coastline of Oman Sea which is rich in nutrients. The aim of the present study was to test the hypothesis which it canbe used as a source of protein in shrimp diets. The experiment was conducted in a laboratory, where 3 grams shrimp juvenile acclimation in a 5,000 L tank. They were then kept in plastic tank each containing 300 L water and 30 shrimp juveniles were fed daily (4% of biomass) in four equal portions with one of four diets, each with four repetitions for a period of 45 days. All diets contained 33% crude protein (isoprotein) and 355 kcal 100 gr−1 (isocaloric), with different percentages of sargassum powder: Diet “A” 15%; Diet “B” 10%, Diet “C” 5%, and Diet “D” without seaweed (control diet). Algae were collected, rinsed, dried and ground up for the feed formulations. Weight of the animals was measured at the beginning of the experiment and at 15-day intervals to assess their growth. The physicochemical variables of the water were measured every 2 days. Final biomass, biomass gain and specific growth rate (SGR) exhibited no significant differences between treatments (P>0.05). Survival rate was almost equal under the four experimental conditions, 95.2% to 97.00% (P>0.05). Diets “A” and “B”, with a greater content of algae, exhibited better feed conversion (1.15:1 and 1.17:1) than diets “C” and “D” (1.30:1 and 1.33:1) (P<0.05). The physical-chemical variables of the water showed no significant variation and remained within the standards necessary for the wellbeing of the shrimps. If sufficient biomass of beached algae can be practically and economically collected, it may be used as a component in the making of shrimp feed.