Effect of different dietary lipid levels on digestive enzyme activity and immune status of the Pacific white shrimp Litopenaeus vannamei at two salinity levels

The purpose of the current study was to examine the effect of five varying lipid levels (6%, 8%, 10%, 12%, and 14%) combined with two different salinity levels (15 and 30 ppt) on growth performance, survival, serum antioxidant response and digestive enzyme activity of white leg shrimp, Litopenaeus vannamei. The study was conducted in thirty rectangular Separate tanks (measuring 66 x 47 x 44 cm, holding 50 L) reinforced with water salinity levels of 15 and 30 ppt over a period of 90 days. There were 3 replicates for each treatment; each tank held 30 post-larvae with a range body weight of 0.02g. Shrimp were fed experimental diets contain almost 35% crude protein four times a day, equivalent to 14% of their initial body weight, which was slowly decreased to 5% by the end of the study. The best treatment, which contained 6% lipid and salinity of 30 ppt, showed the best result in growth performance and survival (%). The levels of trypsin activity in the intestines were notably higher in white shrimp in the group exposed to a salinity of 30 compared to those in the group exposed to a salinity of 15. The greatest amount of lipase activity was observed when shrimp were fed diets with 6, 8, and 10% lipid levels. It was determined that shrimp fed a diet containing 14% lipid at 15 and 30 ppt had the highest crude lipid content, while shrimp at 15 ppt exhibited the highest GSH-Px activity. These findings were observed under experimental circumstances.