Biochemical composition of eggs and nauplii in White Pacific Shrimp,Penaeus vannamei(Boone), in relation to the physiological condition of spawners in a commercial hatchery

Abstract

In this study, triacylglycerol, cholesterol and glucose were measured in nauplii of Penaeus vannamei (Boone) to explain high and low survival rates from nauplii to zoea in a commercial hatchery. Triacylglycerol and glucose levels were significantly higher in nauplii that had increased survival rates to zoea. No significant differences were found in nauplii size or cholesterol levels. The influence of the long-term effect of ablation of broodstock on the biochemical composition of egg and nauplii was also determined. As the days after ablation increased, the glucose and triacylgyceride level in eggs, and the glucose levels in nauplii decreased. The broodstock had higher fecundity and body length 96 days after ablation, but the more recently ablated broodstock (18 days) produced the largest nauplii, which could indicate a higher development rate. A nauplii condition index was calculated from nauplii triacylglycerol levels, percentage of viable nauplii and nauplii length. A decline in this condition index was observed with increased days after ablation. The biochemical composition of egg and nauplii can be associated with the physiological status of the broodstock. In turn, the hatching success and survival to zoea are affected by the fuel levels. The differences in egg and nauplii fuels from broodstock with different time after ablation suggest that reproductive exhaustion of the broodstock is also related to insufficient metabolic fuel which, in turn, has an effect on larval viability.