Effects of dietary oxidized oil on growth performance, meat quality and biochemical indices in poultry – a review

Lipids (fats and oils) are a concentrated source of energy in poultry diets that improves palatability, feed consistency, provides essential fatty acids and increases the absorption of fat-soluble vitamins. Fresh oil is an expensive energy source and its exposure to air, heat, metallic catalyst during storage and processing may lead to its oxidative deterioration. This review highlights the response of modern poultry to dietary oxidized oil on growth performance, nutrients digestibility, gut health, carcass characteristics, meat quality, blood chemistry and tissue oxidative status. Literature shows that in moderately (peroxide value (PV): 20 to 50 meq kg⁻¹) and highly (PV: 50 to 100 meq kg⁻¹ or above) oxidized oils, lipid peroxidation causes rancid odours and flavours that negatively affect feed palatability, reduces intestinal villus height that decreases the surface area available for nutrients absorption. The oxidation products also damage fat soluble vitamins (A, D, E and K) in blood resulting in an oxidative stress. The use of oxidized oil in poultry diets has no significant effect on dressing percentage, pH and meat colour, whereas carcass weight decreases and drip loss of meat increases. Overall, there is a contradictory data regarding the influence of oxidized oil in poultry feed depending on the PV and inclusion levels. The reviewed literature shows that the use of mildly oxidized (PV < 20 meq kg⁻¹) oil in poultry feed with 4 to 5% inclusion level decreases the feed cost and ultimately cost of poultry production without compromising their growth performance. It can, therefore, partially replace fresh oil as an efficient, cost effective and sustainable energy source in poultry diets.