Photoperiods and diets to control of cannibalism in piracanjuba (Brycon orbignyanus) larviculture

Abstract

Larviculture is a critical step in fish production for the high mortality rates occurring in the early stages of fish life. The causes of this mortality are linked to food and behavioral issues such as diet adequacy to larval development stage and the tendency to cannibalism. The piracanjuba (Bryconorbignyanus) is a neotropical species with great aptitude for captive production, but this species during the larval phase presents intense cannibal activity. The cannibalism in the larval phase is pointed out with a great obstacle in the development of the production of this species. The manipulation of the photoperiod and the use of adequate diet are strategies to reduce cannibalism already proven in several species. In order to reduce the rates of cannibalism in piracanjuba larvae, we evaluated the zootechnical performance and quantitative expression of mLeptina and mBmal1 in the initial larvae in different photoperiods (12L: 12D and 24L: 00D) and diets (artemianauplii and artificial micro diet). It was observed that diet and photoperiod influence on the performance of piracanjuba larvae (Bryconorbignyanus) in the initial phase of larviculture. Feeding with artemianauplii and 24L: 00D photoperiod reduce the rates of cannibalism in intensive piracanjuba larvae. Larvae of piracanjuba kept under constant luminosity and fed with artemianauplii present higher levels of expression of mLeptina, which is related to the reduction in cannibalism rates. The expression of mBmal1 is directly related to the final weight of the larvae.