title: Fatty acid biosynthesis and lipogenic enzyme activities in subcutaneous adipose tissue of feedlot steers fed supplementary palm oil or soybean oil.
abstract: We hypothesized that supplementing finishing diets with palm oil would promote adipocyte differentiation in subcutaneous adipose tissue of feedlot steers, and that soybean oil supplementation would depress adipocyte differentiation. Twenty-eight Angus steers were assigned randomly to 3 groups of 9 or 10 steers and fed a basal diet without additional fat (control), with 3% palm oil (rich in palmitic acid), or with 3% soybean oil (rich in polyunsaturated fatty acids), for 10 wk, top-dressed daily. Palm oil had no effect (P > 0.05) on ADG, food intake, or G:F, whereas soybean oil depressed ADG (P = 0.02), food intake (P = 0.04), and G:F (P = 0.05). Marbling scores tended (P = 0.09) to be greater in palm oil-fed steers (Modest(09)) than in soybean oil-fed steers (Small(55)). Subcutaneous adipocyte mean volume was greater in palm oil-fed steers (515.9 pL) than in soybean-supplemented cattle (395.6 pL; P = 0.01). Similarly, glucose and acetate incorporation into total lipids in vitro was greater in subcutaneous adipose tissue of palm oil-fed steers (119.9 and 242.8 nmol·3h(-1)·10(5) cells, respectively) than adipose tissue of soybean oil-fed steers in (48.9 and 95.8 nmol·3h(-1)·10(5) cells, respectively). Glucose-6-phosphate dehydrogenase and NADP-malate dehydrogenase activities were greater (P ≤ 0.05) in subcutaneous adipose tissue of palm oil-fed steers than in adipose tissue of control steers. Palm oil did not increase palmitic acid or decrease oleic acid in subcutaneous adipose tissue or LM, but decreased (P ≤ 0.05) myristoleic, palmitoleic, and cis-vaccenic acid in adipose tissue, indicating a depression in stearoyl-coenzyme A desaturase activity. Soybean oil increased the proportion of α-linolenic acid in adipose tissue and muscle and increased linoleic acid and 18:1trans-10 in muscle. We conclude that palm oil supplementation promoted lipid synthesis in adipose tissue without depressing feed efficiency or increasing the palmitic acid content of beef.
authors: Department of Animal Science, Texas A & M University, College Station, TX 77843, USA.
authors: S H
authors: SH
authors: Choi
authors: G O
authors: GO
authors: Gang
authors: J E
authors: JE
authors: Sawyer
authors: B J
authors: BJ
authors: Johnson
authors: K H
authors: KH
authors: Kim
authors: C W
authors: CW
authors: Choi
authors: S B
authors: SB
authors: Smith
mesh_terms: D050154:Adiposity / Q000187:drug effects*; D000821:Animal Feed / Q000032:analysis; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism*; D005410:Flame Ionization / Q000662:veterinary; D050155:Lipogenesis / Q000187:drug effects; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D000073878:Palm Oil; D019308:Palmitic Acid / Q000378:metabolism*; D010938:Plant Oils / Q000008:administration & dosage / Q000378:metabolism*; D011897:Random Allocation; D013024:Soybean Oil / Q000008:administration & dosage / Q000378:metabolism*; D050151:Subcutaneous Fat / Q000187:drug effects* / Q000254:growth & development
chemical_list: D005229:Fatty Acids, Monounsaturated; D010938:Plant Oils; D019308:Palmitic Acid; D000073878:Palm Oil; D013024:Soybean Oil