Nonruminant Nutrition: Weanling Pig - Vitamin & Mineral

Poultry fat has become a more economical source of energy than byproducts currently used. Therefore, this study was conducted to determine the effects of dietary fat source (poultry fat or beef tallow) in finishing diets for cattle on the fatty acid composition of beef. Sixty Angus crossbred steers (410.8 kg initial BW) were stratified by source, blocked by weight, and assigned within block to 15 pens (4 steers/pen). Pens were then assigned randomly within blocks to one of three dietary treatments consisting of: 1) a corn-soybean meal control diet devoid of supplemental fat (Ctrl); 2) the control diet formulated with 4% tallow (TAL); or 3) the control diet formulated with 4% poultry fat (PF). Cattle were fed for 112-d and harvested at a commercial beef packing plant. Wholesale ribs were collected during carcass fabrication (357.7, 357.3, and 369.5 kg for carcasses of Ctrl, TAL, and PF-fed cattle, respectively), and samples of subcutaneous fat and LM were analyzed for fatty acid composition (reported as mg/g wet tissue). In the LM, total saturated fats (14:0, 15:0, 16:0, and 18:0) were similar (P > 0.10) among diets. Furthermore, total monounsaturated fatty acids (MUFA) were not (P > 0.10) affected by finishing diets. The LM from the steers fed PF had increased (P < 0.05) 18:2 and total PUFA than the LM of the steers fed Ctrl or TAL-diets. Conversely, the LM of TAL-steers had lower (P < 0.05) concentrations of 20:3 than Ctrl or PF-fed steers. The only changes detected in subcutaneous fat were steers that consumed the Ctrl-diet had the highest (P < 0.05), and PF-fed steers had the lowest (P < 0.05), 17:0 concentrations. Furthermore, subcutaneous fat from TAL-fed steers had lower (P < 0.05) conjugated linoleic acid concentrations than fat from controls and PF steers; however, diet did not (P > 0.10) affect total saturated, MUFA, PUFA, omega-6, or trans fatty acids. Feeding finishing steers diets formulated with poultry fat did not negatively impact the fatty acid composition of subcutaneous fat or the LM, and may serve as an alternative to beef tallow as a source of energy for cattle finishing diets.