Dried distillers grains with solubles (DDGS) is currently a common ingredient in swine diets; however, it can have negative effects on carcass quality because DDGS contains 10 to 11% fat. Because L-carnitine is involved within the energy metabolism in the body, it is theorized that dietary L-carnitine may increase the dietary energy utilization in DDGS diets fed to pigs and improve fat quality. The objective of this study was to investigate the effects of dietary L-carnitine and DDGS on growth performance, carcass characteristics, and fat and loin quality of finishing pigs. A total of 1,104 barrows and gilts (initially 80 lb) were used in a 109-d study. Pigs were blocked by weight and randomly assigned to 1 of 6 treatments with 7 replications per treatment. Treatments were arranged as a 2 x 3 factorial with main effects of added DDGS (0 or 30% in Phases 1, 2, and 3 and 20% in Phase 4) and L-carnitine (0, 50, or 100 ppm). Dietary treatments were corn-soybean meal-based and fed in 4 phases.
Overall (d 0 to 109), dietary L-carnitine improved (P < 0.02) ADG, which resulted in greater (P < 0.02) final BW with the response tending to be linear (P < 0.07). For F:G, a DDGS x L-carnitine interaction (quadratic, P < 0.01) was observed. This was the result of pigs fed 50 ppm L-carnitine, with no DDGS having better F:G than pigs fed 0 or 100 ppm, but in diets containing DDGS, pigs fed 50 ppm L-carnitine had worse F:G compared with those fed 0 or 100 ppm. In carcass traits, pigs fed dietary L-carnitine had greater (P < 0.02) HCW compared with those not fed dietary L-carnitine. The increase in dietary L-carnitine also increased carcass weight (quadratic, P < 0.03), carcass yield (quadratic, P < 0.07), and backfat (quadratic, P < 0.04), with the maximum response observed from pigs fed 50 ppm dietary L-carnitine. In loin quality, feeding dietary L-carnitine increased (P < 0.04) purge loss compared with pigs fed no L-carnitine, with the response being linear (P < 0.03). In jowl fat fatty acid profile, as expected, feeding dietary DDGS increased (P < 0.001) linoleic acid, total polyunsaturated fatty acids (PUFA), the ratio of unsaturated fatty acids to saturated fatty acids, and iodine value (IV) compared with feeding no dietary DDGS; however, feeding L-carnitine did not alter jowl fatty acid composition.
Feeding dietary L-Carnitine improved ADG and carcass weight, with the maximal response observed at 50 ppm, but dietary L-Carnitine did not affect loin or fat quality.
W Ying, JM DeRouchey, MD Tokach, SS Dritz, RD Goodband, TA Houser and JL Nelssen. Effects of dietary L-carnitine and DDGS on growth, carcass characteristics, and loin and fat quality of growing-finishing pigs. 2011. Swine Day, Kansas State University, 319-329.