Effects of dietary L-Carnitine and DDGS on growth, carcass characteristics, and loin and fat quality of growing-finishing pigs

A total of 1,104 barrows and gilts (PIC 337 × 1050, initially 80 lb) were used in a 109-d study to evaluate the effects of dietary L-Carnitine and dried distillers grains with solubles (DDGS) on growth, carcass traits, and loin and fat quality. Pigs were blocked by weight and randomly assigned to 1 of 6 treatments with 7 replications per treatment. Treatments were arranged as a 2 × 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 \u3c 0.02) ADG, which resulted in greater (P \u3c 0.02) final BW with the response tending to be linear (P \u3c 0.07). For F/G, a DDGS × L-Carnitine interaction (quadratic, P \u3c 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 \u3c 0.02) HCW compared with those not fed dietary L-Carnitine. Also, increasing dietary L-Carnitine increased carcass weight (quadratic, P \u3c 0.03), carcass yield (quadratic, P \u3c 0.07), and backfat (quadratic, P \u3c 0.04), with the maximum response observed from pigs fed 50 ppm dietary L-Carnitine. In loin quality, feeding dietary L-Carnitine increased (P \u3c 0.04) purge loss compared with pigs fed no L-Carnitine, with the response being linear (P \u3c 0.03). In jowl fat fatty acid profile, as expected, feeding dietary DDGS increased (P \u3c 0.001) Linoleic acid, total polyunsaturated fatty acids (PUFA), the ratio of unsatu- rated 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 composi- tion. 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.; Swine Day, Manhattan, KS, November 17, 201