Peru Project: Broodstock Diets and Spawning of Colossoma macropomum and/or Piaractus brachypomus Research Update
by Rebecca Lochmann, University of Arkansas at Pine Bluff
ne of the objectives of this Tenth Work Plan project is to determine the effect of improved broodstock nutrition on maturation and spawning performance of Colossoma macropomum and/or Piaractus brachypomus, species native to the Peruvian Amazon and locally known as tambaqui and pacu. Ideally, optimal broodstock diets will be formulated using nutrient sources that are cost effective and readily available in the Amazon region.
Assessment of the diets used previously for Characid broodstock revealed that they contain very low levels of xanthophyll (about 17 mg/kg) but no other carotenoids. Carotenoids are known to influence reproduction in some fish (red sea bream, yellowtail, Atlantic salmon). Furthermore, the natural diets of Characids are rich in carotenoids. Pijuayo (Bactris gasipaes) is a locally available fruit with a deep orange-red color. The fruit is similar to corn in its percentages of protein and lipids, but pijuayo contains mostly beta-carotene and corn contains xanthophyll. Previous research (Mori-Pinedo et al., 1999) has shown that pijuayo and corn could be used interchangeably for growth and body composition in tambaqui fingerlings. In addition, pijuayo is being used indiets for ornamental fishes at Fondepes, a government fish production facility in Peruvian Amazon city of Iquitos.
Assuming pijuayo has no negative effects on pacu growth, health, or
Therefore, pijuayo can be substituted for corn at 16% of the diet without sacrificing growth or health of pacu. Mori-Pinedo et al. (1999) showed that pijuayo or corn could be used up to 55% of the diet for comparable growth and body composition in tambaqui fingerlings. The next step is to determine whether substitution of corn with pijuayo confers any benefits to broodstock Characids in terms of spawning success.
Other work in progress at UAPB indicates additional changes to consider for pacu (broodstock and fingerling) diets. Apparent digestible energy coefficients determined recently for common feedstuffs in pacu indicate that the available energy content of wheat bran is about half that of fish meal, soybean meal, or corn (Fernandes and Lochmann, unpublished). Apparent protein and lipid digestibility coefficients are also being determined for these feedstuffs in pacu.