Hafezieh

The brown seaweedSargassum illicifolium is abundant along the Iranian coastline

of the Oman Sea in which is rich in nutrients. The aim of the present study was to test the hypothesis which it can be used as a source of protein in shrimp diets. The experiment was conducted in a laboratory, where 6g shrimp juvenile acclimation in a 5000L tank. They were then kept in plastic tank containing 300L water and 30 shrimp juveniles in which were fed daily (3% of biomass) in four equal portions with one of four different diets in four repetitions for a period of 45 days. All diets contained 33% crude protein (isoprotein) and 355 kcal 100 g⁻¹ (isocaloric), with different percentages of Sargassum powder: Diet “A” 15%; Diet “B” 10%, Diet “C” 5%, and Diet “D” (Control) without seaweed. 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 also at 10-day intervals to assess their growth rate. The physical and chemical variables of the water were measured every 2 days. Final biomass, it's gain and specific growth rate (SGR) exhibited no significant differences between treatments (P>0.05). Survival rate 95.2% to 97.00% was almost equal under the four experimental conditions (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 physicochemical variables of the water showed no significant variation and remained within the standards necessary for the wellbeing of the animals. If sufficient biomass of beached algae can be practically and economically collected, it can be used as a component in the making of shrimp feed.