Biodiesel‐derived glycerol as a dietary maize replacement for silver catfish (Rhamdia quelen) during the fattening phase

摘要

Abstract The aim of the present study was to assess the effects of crude biodiesel‐derived glycerol on the zootechnical performance, carcass and fillet chemical composition, and blood parameters of silver catfish (Rhamdia quelen) during the fattening phase. A total of 150 adult silver catfish specimens (mean weight 188.89 ± 0.60 g) were distributed in thirty 1000 L‐tanks containing a water recirculation system with mechanical filter and biofilter, in a completely randomized design comprising six treatments, 0, 20, 40, 60, 80 and 100 maize replacement by glycerol, with five repetitions each. The experiment was conducted for 206 days. Silver catfish morphometric parameters were not influenced (p > 0.05) by the glycerol maize replacement, although silver catfish standard length and width exhibited linear improvements (p < 0.05) with the dietary glycerol replacement. Fillet yield was affected (p < 0.05) by glycerol maize replacement, where the 80 replacement treatment led to better fillet yields (46.04), differing only from the 20 replacement treatment (42.40 fillet yields). The blood plasma levels of glucose, pyruvic glutamic transaminase and triglycerides were influenced by the treatments (p < 0.05). The crude protein of fillet was influenced by the treatments (p < 0.05), where the highest value was observed in 100 glycerol maize replacement. Therefore, crude glycerol derived from biodiesel production is a suitable alternative energy source ingredient for silver catfish during their fattening phase, as it can replace maize in up to 100.