Dietary effects of seaweed Sargassum ilicifolium on reducing cholesterol level of white leg shrimp (Litopenaeus vannamei)

In this research, the nutritional effects of Sargassum ilicifolium Chabahar Bay, Oman Sea, on cholesterol levels of white-leg shrimp (Litopenaeus vannamei) were studied. The seaweed was collected from coastal areas, rinsed, dried, powdered and the nutritional values were measured in the laboratory. A part of protein resources of shrimp feed replaced with seaweed powder in four treatments (D: as control without any replacement) C: with 5%, B: 10 % and A: 15% seaweed replacement, each with three replicates in order to obtain isonitrogenus 33% CP., and Isocaloric (13% fat and 15% carbohydrate) feed.  Dried diets were used according to the daily need of shrimp, calculated after each 10 day biometry. Water stability and absorption capacity of the pellets in sea water were measured and compared statistically. Juvenile shrimps (Initial body weight=3 g) were acclimated for one week under hatchery conditions and were fed 3-5% of their body weight. Abiotic parameters, weight and length biometry were measured on day two and day 10, respectively. After 45 days final biometry, body analysis were measured, and muscle colorimeter were conducted using HPLC. There were no significant differences (p>0.05) between body lipid among treatments, but cholesterol content (mg/100gWW) showed significant differences (p<0.05), the lowest (121.68±12.12) was in treatment A, and the highest in D (147.92±11.02).  Treatments A and B showed color changes to pink- partial orange and pink in shrimp muscle with no differences compared to white and no color in shrimp in treatments C and D. It seems that this color change plays a major role in market acceptability.