Degummed Crude Canola Oil Supplementation Affects Fat Depot Melting Points in Purebred and First-Cross Merino Sheep

Abstract

The objective of this study was to test the hypothesis that degummed crude canola oil (DCCO) will lower fat melting points (FMP) of both visceral and subcutaneous fats in lambs. Twenty-four lambs comprising purebred and first-cross Merino progeny from Dorset, White Suffolk and Merino sires mated to purebred Merino ewes were supplemented with varying levels of DCCO over a nine-week period. The experimental treatment groups were: Control (1kg plain wheat-based pellets only), Medium (500g plain wheat-based pellets + 500g wheat-based pellets containing DCCO), and High (1kg wheat-based pellets containing DCCO at a concentration of 50ml/kg) supplementation levels. The flock comprised eight wether and ewe lambs per treatment. However, at the end of the trial, four Merino ewes were retained in the flock for breeding purposes, while the remaining twenty lambs were slaughtered in a commercial abattoir. Visceral fat samples were taken from the kidney region and subcutaneous fat samples were taken from the Longissimus dorsi muscle. FMP was determined using temperature slip point methodology in the laboratory. DCCO had significant effects on the FMP of both subcutaneous (p 0.0002) and visceral (p<0.0001) fats, with the lowest FMP achieved at high levels of supplementation in both fat depots. Significant sire breed differences (p<0.0001) were also detected in which Dorset-sired progeny had the highest melting points in both fat depots. The results of this study indicate that within fat depots, DCCO supplementation produced softer fats with lower melting points, suggesting potentially healthier fats likely to contain higher levels of unsaturated fatty acids.