title: Manipulation of the n-3 polyunsaturated fatty acid content of muscle and adipose tissue in lambs.
abstract: Fifty Suffolk-crossbred wether lambs, with an initial live weight of 29 +/- 2.1 kg, were allocated to one of five concentrate-based diets formulated to have a similar fatty acid content (60 g/kg DM), but containing either linseed oil (high in 18:3n-3); fish oil (high in 20:5n-3 and 22:6n-3); protected linseed and soybean (PLS; high in 18:2n-6 and 18:3n-3); fish oil and marine algae (fish/algae; high in 20:5n-3 and 22:6n-3); or PLS and algae (PLS/algae; high in 18:3n-3 and 22:6n-3). Lambs were slaughtered when they reached 40 kg. Growth performance and intake were similar (P > 0.35) among treatments. By contrast, gain:feed was higher (P < 0.05) in lambs fed the fish oil compared with the linseed oil or PLS/algae diets. Total fatty acid concentration (mg/100 g) in the neutral lipid of the longissimus muscle was not affected by treatment (P > 0.87) but was least (P < 0.05) in the phospholipid fraction in lambs fed the linseed oil diet. Lambs fed either diet containing marine algae contained the highest (P < 0.05) percentage of 22:6n-3 in the phospholipid (mean of 5.2%), 2.8-fold higher than in sheep fed the fish oil diet. In lambs fed the fish/algae diet, the percentage of 20:5n-3 was highest (P < 0.05), contributing some 8.7, 0.8, and 0.5% of the total fatty acids in the muscle phospholipid, neutral lipids, and adipose tissue, respectively. The percentage of 18:3n-3 in the phospholipid fraction of the LM was highest (P < 0.05) in lambs fed the linseed oil diet (6.9%), a value double that of sheep fed the PLS diet. By contrast, lambs fed the PLS diet had twice the percentage of 18:3n-3 in the muscle neutral lipids (3.8%) than those offered the linseed oil diet, and 5.5-fold greater than lambs fed the fish/algae treatment (P < 0.05), an effect that was similar in the adipose tissue. The percentage of 18:2n-6 was highest (P < 0.05) in lambs fed the PLS diet, where it contributed 33.7, 10.1, and 11.2% in the muscle phospholipid, neutral lipids, and adipose tissue, respectively. The highest (P < 0.05) muscle PUFA-to-saturated fatty acid (P:S) ratio was obtained in lambs fed the PLS diet (0.57), followed by the PLS/algae diet (0.46), and those fed the fish oil or linseed oil diets had the lowest ratios (0.19 and 0.26, respectively). The favorable P:S ratio of lambs fed the PLS/algae diet, in conjunction with the increased levels of 20:5n-3 and 22:6n-3, enhanced the nutritional qualities of lamb to more closely resemble what is recommended for the human diet.
authors.affiliation: ASRC, School of Agriculture, Harper Adams University College, Edgmond, Newport, Shropshire TF10 8NB, United Kingdom.
authors.forename: S L
authors.initials: SL
authors.lastname: Cooper
authors.forename: L A
authors.initials: LA
authors.lastname: Sinclair
authors.forename: R G
authors.initials: RG
authors.lastname: Wilkinson
authors.forename: K G
authors.initials: KG
authors.lastname: Hallett
authors.forename: M
authors.initials: M
authors.lastname: Enser
authors.forename: J D
authors.initials: JD
authors.lastname: Wood
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry* / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D002149:Energy Intake; D056890:Eukaryota; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000032:analysis* / Q000378:metabolism*; D005395:Fish Oils / Q000008:administration & dosage / Q000378:metabolism; D019787:Linoleic Acid / Q000008:administration & dosage / Q000378:metabolism; D008043:Linseed Oil / Q000008:administration & dosage / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000378:metabolism; D009751:Nutritional Requirements; D009753:Nutritive Value; D010743:Phospholipids / Q000032:analysis; D011897:Random Allocation; D012756:Sheep / Q000254:growth & development* / Q000378:metabolism
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D010743:Phospholipids; D008043:Linseed Oil; D019787:Linoleic Acid