The effect of salinity and dietary protein on the hemolymph indices in whiteleg shrimp (Litopenaeus vannamei Boone, 1931) juvenile

In this study, the effects of different dietary protein and salinity levels on cellular parameters of hemolymph in white leg shrimp (as a part of immune system) of the white leg shrimp (Litopenaeus vannamei) juvenile were studied. The number of 350 shrimps with the average weight of 5.55±0.18 g and length of 8.81±0.15 cm were distributed randomly in 27 ten tones (length: 600 cm, width: 170 cm and height: 100 cm) concrete tanks. A 3×3 factorial experimental including three levels of salinity (0-3, 12-15 and 32-35 ppt) and three dietary protein levels (25, 35 and 45%). Experimental shrimps were fed to satiation 4 times a day throughout the experimental 56 days. According to the results cellular parameters like: total hemocytes count (THC) and differential hemocyte count (DHC) were analysed and recorded. The dietary protein levels 35% and salinity of 32-35 ppt had direct positive impact on THC and granular cells (GC). Although the semi granular poisonous cells have been decreased with the increase in both of the experimental variables (P≤ 0/05) and no effected on the agranular cells. So based on the results of this study, the protein diet with the 35% is suggested for L. vannamei. Taking in to consideration the results of the study we can say the best water salinity for culture of this species is 32-35 ppt.