Crude glycerinmay contain relatively lowconcentrations ofmethanol
resulting fromthe chemical processing of biodiesel. Ingestedmethanol is
converted into formic acid, which, in excess, seriously harms animals
causing, for instance, blindness, nervous system depression, motor alterations
and metabolic acidosis in poultry and mammal production
(Lammers et al., 2008). However, such a problem can be overcomewithout
effort in aquaculture sincemethanol is stripped from fish diets under
high temperature processing, i.e., extrusion cooking. Moreover, inclusion
of small amounts of glycerin in diet formulations was proven to improve
pellet durability and machinery efficiency, reducing circa 50% of energy
costs in feed processing (Groesbeck et al., 2008; Shields, 2009).
Nile tilapia is a rather important aquaculture commodity, the quest
for surrogate dietary energy sources for fish farming purposes a true
need, and the increased availability and low cost of CGL a reality. This
work thus assessed the digestibility and effects of graded levels of dietary
CGL on growth, hematological parameters and carcass composition
of Nile tilapia.