Fatty acid composition of different fat depots from hair and wool x hair crossbred lambs supplemented with highly digestible fiber containing agro-byproducts on pasture

Abstract Text:

Agro-byproducts such as soy hull and corn gluten have been recognized as economical sources of feeds for small ruminants because they can provide supplemental nutrients for small ruminants with highly digestible fiber. However, their effect on the fatty acid profile of different fat depots in lambs has not been completely studied. This study was conducted to determine the fatty acid composition of different fat depots from grazing lambs supplemented with highly digestible fiber containing ago-byproducts. Thirty-six, 7.5-mo-old purebred hair (Barbados Blackbelly and St. Croix) and crossbred wool (Dorset) x hair lambs grazed predominantly Jesup tall fescue pasture. Lambs were randomly assigned to a pasture-only, or a soy hull (SH) or corn gluten feed (CGF) supplemented group balanced by breed type. Supplement was provided at 2% of BW daily at individual feeding stations. After 77 d of grazing, lambs were slaughtered using standard procedures. Intramuscular, subcutaneous and kidney fats were obtained from each carcass. Total lipids from each fat depot sample were extracted by the chloroform-methanol method. Extracted lipids were prepared for the fatty acid methyl esters (FAME) and then analyzed by a gas chromatography. All data were analyzed as a completely randomized design with a 2 x 3 factorial treatment arrangement: breed type (pure- or cross-bred) and diet (pasture-only, pasture plus SH or CGF) as main effects. The fatty acid profiles of different fat depots from lambs were significantly influenced by supplementation. Compared with lambs supplemented with SH or CGF, pasture-only fed lambs had higher concentrations of gamma-linolenic (C18:3n6; 0.50 or 0.52 vs 0.64 %), arachidonic (C20:4n6; 2.10 or 2.06 vs 3.31 %), eicosapentaenoic (C20:5n3; 0.46 or 0.36 vs 1.06%) and docosahexaenoic (C22:6n3; 0.55 or 0.52 vs 1.27%) acids, but lower (P < 0.05) concentrations of palmitic (C16:0; 17.0 or 18.1 vs 15.9%) and oleic (C18:1n9; 33.8 or 32.8 vs 29.1%) acids in intramuscular fat;  higher (P < 0.05) concentrations of myristoleic (C14:1n5), palmitoleic (C16:1n7), alpha-linolenic (C18:3n3; 1.80 or 1.24 vs 2.84%) and C18:3n6 (0.83 or 0.65 vs 2.66%) acids, but a lower (P < 0.01) concentration of C18:1n9 in subcutaneous fat; and a higher (P < 0.01) concentration of C14:1n5, but a lower concentration of C18:1n9 in kidney fat. The results indicate that fresh lamb from pasture only fed-lambs might have healthier fatty acid profiles compared with that from lambs supplemented with soy hull or corn gluten feed.

Keywords: Fatty Acid, Lamb, Agro-byproduct