Effect of environmental temperature and a protected lipid supplement on the fatty acid profile of ovine longissimus dorsi muscle, liver and adipose tissues

Abstract

The objective for this study was to determine whether there is an alteration in the fatty acid profile of lipid in tissues from sheep exposed to two different temperatures (0°C — cold and 23°C — warm) with or without a protected lipid supplement in the diet. Twenty-four Suffolk-cross 5-month-old wether lambs were randomly allotted to six treatments of warm control, warm lipid, cold control, cold lipid, pairfed-cold control and pairfed-cold lipid of a 5-week, 3×2 factorial environment×diet feeding experiment. Cold temperature exposure or dietary lipid supplementation did not alter the total lipid content (%) in the longissimus dorsi muscle (LD), liver, and subcutaneous, mesenteric and perirenal adipose tissues. However, lipid content of the internal adipose fat depots was 20% higher ( P<0.05) than that of the peripheral (subcutaneous) depot. For the composition of fatty acids, the primary difference between the three adipose tissues appeared to be in the relative proportions of the 16:0, 18:0 and 18:1 fatty acids, with the two internal adipose tissue depots containing more ( P<0.05) 16:0 and 18:0 fatty acids compared with the peripheral subcutaneous fat depot. In LD and subcutaneous adipose tissue, saturated fatty acids (14:0, 15:0, 16:0, 17:0 and 18:0) constituted approximately 45% of the total fatty acid present. In the liver and mesenteric and perirenal adipose tissues, saturated fatty acids accounted for 52–55% of the total fatty acids. In LD and liver, polyunsaturated fatty acids (18:2ω6, 18:3ω3, 20:4ω6 and 20:5ω3) ranged from 8 to 20% of the total fatty acids whereas, in the adipose tissues, polyunsaturated fatty acids accounted for 4.3–5.5% of the total fatty acids. In summary, except for differences in some individual fatty acids in the tissues, effects of environment or dietary lipid supplementation on the fatty acid composition of the tissues were small in magnitude.