The team of D.D. Boler, D.M. Fernández-Dueñas, L.W. Kutzler, J. Zhao, R.J. Harrell, D.R. Campion, F.K. McKeith, J. Killefer and A.C. Dilger set out to evaluate the effect of feeding oxidised corn oil with or without a dietary antioxidant (AOX) on performance, tissue oxidative status and meat quality in barrows.

One hundred sixty barrows were arranged in a 2×2 factorial design of treatments in a complete randomised block design with eight pens per treatment and five pigs per pen.

Diets contained 5.0mg per kg of one of two types of corn oil (fresh or oxidised), with or without antioxidant.

Final oxidised oil was produced in a heated container by continuously bubbling air heated to 95°C at a rate of 80L per minute to reach a target peroxide value of approximately 150 and 7.5mEq per kg in the final diet.

After 56 days, barrows fed diets formulated with fresh oil had increased average daily gain (P=0.03) and average daily feed intake (P=0.04) and heavier final bodyweight (P=0.03) than barrows fed oxidised oil.

Increased gain:feed ratio (P=0.07) was observed for barrows fed diets with AOX after 28 days of feeding but not after 56 days of feeding (P=0.67) when compared with barrows not fed AOX.

An increase (P=0.06) in plasma thiobarbituric acid reactive substances (TBARS) values, a decrease (P=0.03) in plasma glutathione peroxidase (GPx) enzyme activity and a decrease (P=0.01) in liver vitamin E concentrations were observed in barrows fed diets with oxidised oil.

Dietary AOX reduced plasma protein carbonyl content regardless of oil type (P=0.04). Barrows fed fresh oil had 4.4 per cent heavier average hot carcass weight (P=0.01) and 0.7 percentage units increase in dressing percentage (P=0.01) compared with barrows fed oxidised oil.

Loin TBARS values from barrows fed AOX were lower (P<0.001) after 14 and 21 days of storage in both fresh and oxidised oil groups.

In summary, the study published in the Journal of Animal Science revealed that feeding oxidised oil impaired growth performance and caused oxidation stress. Dietary AOX partially ameliorated the negative effects of oxidised oil in finishing pigs by reducing protein oxidation and improving shelf life.

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February 2013