Reproductive performance and offspring quality in mud crab (Scylla paramamosain) broodstock fed different diets

A 2-month feeding trial was conducted toevaluate the reproductive performance andoffspring quality of mud crab (Scyllaparamamosain) females fed either a mixture offresh food items (squid, shrimp, trash fish andArtemia biomass) or two experimentaldiets developed for penaeids. Before testinitiation, mud crab females with an averageindividual wet weight of 200–300 g wereacclimated for 2–3 days and reared together inone concrete tank of 2.0 × 0.5 × 8 m untilspawning. After spawning, the spent spawnerswere unilaterally eyestalk ablated and randomlydivided (20 animals/treatment) over three tanksof the same size and subjected to the dietarytreatments. Spent spawners were used toeliminate the effect of feeding history.There were only minor differences inreproductive performance between dietarytreatments. No differences were observed in theduration of the latency period from eyestalkablation to spawning. Fecundity was onlymarginally higher for the broodstock fed thecontrol diet. Also egg quality seemed onlyslightly affected by the treatments. Egghatching rates were slightly higher in crabsfed the formulated diets compared to thosecrabs fed the fresh diet. The onlystatistically significant difference (p < 0.05) observed however was in egg hatchingrate between the control diet and diet A2. Incontrast, the crabs fed the fresh diet producedstronger larvae as determined by a starvationtest.We therefore conclude that artificial dietsresulted in reproduction success comparable tothe use of fresh food. The nutritionalcomposition of the artificial diets couldhowever be improved in order to produce larvaeof optimal quality. Based on our researchfindings, the protein level and n-3 HUFA levelin the diet warrants further investigation inthis respect.