Maturation performance of <i>Penaeus vannamei</i> co-fed <i>Artemia</i> biomass preparations

Few shrimp hatcheries successfully propagate captive broodstock on a commercial scale. Diets for acceptable maturation performance of Penaeus vannamei have typically relied on the inclusion of marine polychaetes (bloodworm) from Panama or Maine, USA, which are expensive and are of unpredictable supply. Studies were therefore undertaken at experimental and commercial scale to replace or supplement the polychaetes by frozen ongrown Artemia which were either non-enriched or bioencapsulated with specific boosters. In experiment 1 the control diet consisted of frozen squid only and was evaluated against broodstock diets where 60% of the squid was substituted by bloodworm or enriched Artemia biomass. Effects were evaluated for males and females as sexes were kept in separate broodstock tanks. In experiment 2 the control treatment received a mixture of natural feed, including bloodworm. For the two other treatments, the bloodworm fraction was replaced by non-enriched Artemia adults, respectively. Finally, an evaluation at commercial scale was made comparing two feeding regimes based on a combination of semi-moist pellets and fresh-frozen marine organisms. In one of the treatments a portion of the natural food was replaced by an equal amount of enriched, frozen Artemia biomass. Dietary effects on the reproductive performance of the broodstock were evaluated and egg characteristics were monitored. Results from the three experiments confirm that dietary conditions affect the reproductive performance of P. vannamei. Even in a maturation diet consisting of multiple natural food products, frozen adult brine shrimp biomass appears to increase reproduction performance. Although the male diet did not appear to significantly affect mating or fertilization, there was a clear tendency towards improved mating success and hatching when Artemia biomass was included in a mixed diet. Combined effects of improved mating and hatching resulted in significant differences in overall nauplii production. It is therefore concluded that Artemia biomass may be useful as a supplement to or as a replacement for polychaetes in Penaeus vannamei maturation diets