Nutritional strategies for efficient reproductive performance of captive Indian white prawn, Penaeus indicus (H. Milne Edwards, 1837)

Abstract

Broodstock nutrition in penaeid is a vital component of a successful hatchery operation, however, there are still gaps in our present understanding of the nutrient requirements and strategies to optimize successful seed production. The first study determined the influence of different nutrient levels on the maturation of Indian white prawn, Penaeus indicus. Results showed maturation diet with 55/12 protein/lipid combination resulted in best reproductive performance of P. indicus in terms of maturation and offspring quality similar to that achieved in broodstock fed with fresh diet. Experimental maturation diet with the lowest nutritional inclusion resulted in poor maturation rates of broodstock, while treatments with high lipid supplementation resulted in higher lipid accumulation in the hepatopancreas and low survival. The second and third components of the dissertation determined the effect of polychaete extract supplementation on male and female broodstock maturation, respectively. Results showed inclusion (0.25% and 0.50%) of polar lipid fraction (PLF) in the diet resulted in best ovarian maturation with significantly increased ovarian vitellogenin (Vg) expression of female P. indicus. Neutral lipid fraction (NLF) and total soluble fraction (TSF) at 0.50% and 1.00% inclusion levels equally promoted ovarian maturation of female P. indicus broodstock but with lower ovarian Vg expression. All dietary treatments except for 0.25% NLF and TSF improved P. indicus ovarian maturation compared to those fed basal or fresh feed diets. Meanwhile, the lowest inclusion of TSF and NLF resulted in higher sperm counts while PLF did not improve sperm production. Polychaete extract supplementation in the maturation diet of male P. indicus broodstock did not significantly increase sperm count compared to those fed with the basal diet. Male and female broodstock have different reproductive responses to polychaete supplementation, suggesting differences in their requirements, hence, nutritional manipulation should be made sex-specific. Rearing broodstock, either monosex or mixed sex did not influence gonad maturation, sperm quantity and quality, and mating behavior and success. Overall these findings indicate that a sex-specific nutritional intervention is a practical approach to attain efficient gonad maturation and reproductive success in the breeding of P. indicus.