Dietary linseed oil and selenate affect the concentration of fatty acids in selected tissues of sheep

Abstract

The aim of the study was to determine the influence of the addition of 5% linseed oil (LO) and 2 µg Se as selenate (SeVI) per g of diet on body mass gain (BMG), feed conversion efficiency (FCE), and concentrations of fatty acids (FA), especially conjugated linoleic acid (CLA) isomers, in the liver, heart, m. longissimus dorsi (MLD), m. biceps femoris (MBF), subcutaneous fat (SF), perirenal fat (PF), and intermuscular fat (IF) of sheep. Each group comprised 5 lambs with an average initial body weight of 25 ± 2 kg. For 35 days the sheep were fed the control or experimental diets enriched with 5% LO, SeVI, or LO and SeVI combined. The diets with LO, regardless of the presence of SeVI, increased BMG, FCE, and the mass of MBF, MLD, and the liver. The LO treatment increased the concentration of total CLA isomers in the liver, SF, PF, and MLD in comparison with the control. Dietary LO with or without SeVI resulted in negligible changes in the concentration of total CLA isomers in MBF. The diet enriched with LO, irrespective of the presence of SeVI, increased the concentrations of cis- monounsaturated fatty acids (cis-MUFA), polyunsaturated fatty acids (PUFA), as well as unsaturated fatty acids (UFA) in the liver, heart, and especially in SF and PF (i.e. energy storage tissues) compared with the control group and SeVI-fed sheep. Dietary SeVI more effectively increased the capacity of ∆9-desaturation in all adipose tissues as the concentration of cis9,trans11CLA increased in these tissues. The addition of SeVI to the diet decreased the yield of the catabolism of fatty acids in these adipose tissues and both muscles compared with the control sheep or other experimental groups. The diets enriched with LO with or without SeVI increased the nutritional value of MBF, MLD, and adipose tissues as the ratio of unsaturated FA/saturated FA increased. Our results of a short-term study provide useful information for nutritionists carrying out further investigations to improve the nutritional quality of feed for ruminants as well as humans.