Differential Effects of Dietary Acidulated Soybean Oil Soapstock, Cottonseed Oil Soapstock and Tallow on Broiler Carcass Fat Characteristics

Abstract

The degree of saturation of carcass fat (both visceral and muscular) of broilers was significantly affected by the type of dietary fat and its level. The most saturated carcass fat was obtained from feeding diets supplemented with tallow, or diets not containing any fat supplement, followed by dietary acidulated cottonseed oil soapstock (ACS), with soybean oil soapstock (ASS) leading to the least saturated body fat. The effect of ACS seems to be partly due to interference with the metabolic desaturation of stearic acid. Withdrawing the ASS from the diet at 5 weeks of age, or replacing it at this stage by either tallow or ACS, decreased significantly the degree of unsaturation of muscular and visceral fat at 8 weeks. The degree of saturation of visceral fat was reflected in pronounced changes in the latter’s melting point and stability towards oxidation. ACS resulted in body fat having a higher melting point than expected from the degree of its unsaturation. The stability of meat (TBA test) of broilers fed ASS was significantly lower than that obtained on diets containing tallow.