بررسي عوامل موثر در استانداردهاي كيفي پست لاروهاي ميگوي سفيد هندي PENEUS INDICUS

Studying effective factors on qualitative standards of Penaeus indicus post larvae

The quality control measures of the white Indian shrimp {Penaeus indicus) post larvae were studied on the eight, ten, twelve and lifiteen - days old (PL8, PL10.PL12 and PL15 stages). Post larvae activity rates (AR) and their apparent criteria including: color, feeding rates (FR), upper rostral teeth (RT), necrotic spots (NS), muscle to gut rates (MGR) in the sixth abdominal segment and their length were investigated in this study. The tolerance of the post larvae in stressed conditions were tested by salinity drops of 10, 15, 20, 25 and zero ppt and exposure to 300, 250, 200 and 150 ppm formalin during 120 minutes. The results revealed that the PL15 had the highest tolerance and the PL8 had the lowest tolerance in salinity stressed condition. The Pis had tolerance in formaline exposure. The PL15 had positive AR, 2/3 of their gut filled with feed materials, their MGR in the sixth abdominal segment were 3/1 and had 5-6 upper RT. With respect to the effect of age on stress tolerance, it is recommended that grow - out ponds be stocked by the PLs with 15 days old after the mysis stage, together with testing salinity stress and their apparent criteria. However, incompleteness of the upper RT in the PL15 could be due to malnutrition. It is suggested that by improvement of nutrition the apparent criteria and the stress tolerance of the PLs will be improved.