Digestible energy of crude glycerol for pacu and silver catfish

The increase in global biodiesel production is originating a glycerol surplus, which has no defined destination. An alternative to overcome this problem is its use as energy source in animal feeding. In Brazil, Pacu (Piaractus mesopotamicus) is one of the most farmed native fish species, whereas Silver catfish (Rhamdia quelen) is suitable for production in subtropical region. Considering little knowledge about crude glycerol utilization in feeds for Neotropical fish species, it was evaluated the apparent digestibility coefficients (ADCs) for energy of crude glycerol for P mesopotamicus and R. quelen. The digestibility and digestible energy content of crude glycerol can be considered excellent even when compared to energy of common ingredients such as maize and wheat, presenting 0.97 and 0.89 of energy ADCs, and 15.2 and 13.95MJ kg(-1) of digestible energy for Pacu and Silver catfish, respectively In conclusion, crude glycerol is an energetic ingredient with good potential in Brazilian native fish diets.