Two fresh-food maturation diets were tested on wild Penaeus monodon broodstock during a period of 1 month in primary quarantine and 3 months in secondary quarantine; diet A was composed of 70.30% squid (Photololigo sp.), 7.66% marine worm (polychaetes), 7.94% oyster (Crassostrea sp.), and 14.10% pork liver and diet B was composed of 37.39% squid, 16.50% marine worm, 27.14% oyster, and 18.98% pork liver; all on a dry-weight basis. The formulation of diet B was to resemble the ratios of ARA/EPA, DHA/EPA, and n-3/n-6 fatty acids of mature ovaries of wild P. monodon. At the start of primary quarantine, the average weight of the shrimps allocated to the two diets was not significantly different (129.71 ± 2.96 g for females and 87.88 ± 2.49 g for males in the group of diet A and 131.74 ± 1.75 g for females and 88.95 ± 2.05 g for males in the group of diet B). After secondary quarantine, the growth rate of the female shrimps receiving diet B was significantly greater (P < 0.05) than the female shrimps fed diet A (24.44b ± 4.98% compared to 12.89a ± 3.24%, respectively). Shrimp fed diet B performed better than shrimp fed diet A in terms of spawning frequency (85% versus 57%) and fecundity (458,796a ± 35,658 and 245,718b ± 34,736 eggs/spawn, respectively), but number of spawns, hatching rate, fertilization rate and metamorphosis rate of the nauplii into zoea did not differ between the treatments (P > 0.05). The success of diet B in terms of spawning frequency, fecundity, fertilization rate and hatching rate indicates the importance of the ARA/EPA and DHA/EPA ratios in broodstock nutrition of black tiger shrimp. This study also confirmed the success of natural mating of P. monodon in small tanks (1.25 m2 bottom area). The two-step biosecure quarantine procedure was applicable for producing SPF shrimp. |
