Genetic Variation in Intramuscular Fat of Prime Lambs Supplemented with Varying Concentrations of Degummed Crude Canola Oil

The main objective of this study was to quantify the intramuscular fat (IMF) content of Longissimus thoracis et lumborum, biceps femoris and triceps brachii muscles in genetically divergent lambs supplemented with varying levels of degummed crude canola oil (DCCO). Over a nine-week feeding trial, twenty-four first-cross prime lamb progeny from Merino, Dorset and White Suffolk rams mated with purebred Merino ewes under the same nutritional management were supplemented with one of three levels of wheat-based pellets with or without DCCO. The experimental treatments included the Control (1kg of plain wheat-based pellets without DCCO/head/day on dry matter basis), High (1kg of wheat-based pellets containing 50ml of DCCO/kg/head/day on dry matter basis) and Medium (500g of Control + 500g of High wheat-based pellets/head/day on dry matter basis). All lambs had a three-week adjustment period and had ad libitum access to lucerne hay and water. After nine weeks of supplementation, all experimental lambs were slaughtered at a commercial abattoir with the exception of four purebred Merino ewes retained in the flock for breeding purposes. IMF content was analysed using a 2:1 vol/vol ratio of chloroform/methanol extraction and precipitated with 10% potassium chloride. IMF content varied significantly with the level of DCCO supplementation (p<0.0125) and muscle type (p<0.0001). There were also highly significant interactions between sire breed and level of DCCO supplementation (P<0.0016), and muscle type and sex (P