Effects of feeding rate and dietary protein levels on the breeding performance of female yellow catfish ( Pelteobagrus fulvidraco )

Abstract

Nutritional components and feeding strategies are multifarious amongst different producers, whereas they are just designed for fish farming but not suitable for improving the reproductive performance of broodfish. Yellow catfish (Pelteobagrus fulvidraco), an omnivorous species, is one of the important aquaculture fish in China. In order to improve the reproductive performance of female yellow catfish (119.86—134.54 g), four feeding strategies (0.5%, 0.75%, 1% and 1.5% BW/d) and three dietary protein levels (34%, 40% and 46%) were examined, respectively, in the two separate trials. The females with moderate feed restriction (1%) showed significant lower mesenteric fat index (MFI) and higher gonadosomatic index (GSI) than the satiation group (1.5%) and excessive feeding restriction groups (0.5% and 0.75%). Females with high MFI were difficult to be artificially propagated and showed a high mortality rate, whilst the fish at 1.0% feeding rate displayed low mortality rate and high ratios of spawned fish, as well as high percentages of fertilization and hatching. Meanwhile, the offspring of 1.0% feeding rate group showed a low malformation rate and high survival rate. Multiple spawning in the same breeding season are applied in yellow catfish to reduce the number of parent fish and increase the fry production, and gonadal recrudescence after spawning might be affected by different nutrient values including dietary protein levels. In the second trail, female yellow catfish were fed with 34%, 40% and 46% crude protein diet at 1% feeding rate for the second spawning, and the best reproductive and breeding performances were observed in the fish group with 46% crude protein diet. These results demonstrate that 1% feeding rate is optimum for the spawning and reproductive performance of female yellow catfish for the first artificial spawning, and 46% dietary protein group had the best reproductive performances in the second spawning.