Effects of modified tall oil on growing-finishing pig growth performance, carcass characteristics, and meat quality attributes and on body composition and blood and tissue levels of cholesterol, phospholipids, and alpha-tocopherol in adult ovariectomized

Six experiments, utilizing growing-finishing pigs (n = 428; initially 43 kg), were conducted to determine the effects of modified tall oil (MTO) on growth, carcass, and meat quality traits and one experiment was conducted with adult ovariectomized rats (n 26; initially 224 g) to evaluate the effects of MTO on body composition and serum and tissue levels of cholesterol, phospholipids, and alpha-tocopherol. Diets fed to pigs were corn-soybean meal based, nutritionally adequate, and fed in two phases (42.2 to 75.8 and 75.8 to 113.7 kg). Feeding MTO to pigs improved (P < .10) ADG (Exp. 1, 3, 4, and 6), ADFI (Exp. 1 and 4), and feed efficiency (Exp. 3 and 6). Modified tall oil decreased (P < .10) average backfat (Exp. 2, 3, 5, and 6) and increased longissimus muscle area (P = .07) in Exp. 2 and percentage lean (P ≤ .03) in Exp. 2 and 5. Feeding MTO increased (P = .04) intramuscular marbling in Exp. 5. Feeding MTO increased belly firmness (P < .10) in the experiments in which it was determined (Exp. 2, 3, and 4). Rats were pair-fed diets containing an additional 1% soybean oil mix or MTO mix. Rats fed MTO gained weight slower (P ≤ .07) during the six wk trial and had reduced (P = .0006) body fat and increased (P = .0007) fat-free mass. Feeding MTO elicited a tissue enrichment (P < .05) of cholesterol (liver, kidneys, and fat) and phospholipids (liver) and shifted (P ≤ .005) the deposition of alpha-tocopherol to the fat. These data suggest that MTO may be fed to pigs to improve growth, carcass, and meat quality, or a combination of these traits. From the results of Exp. 2 and the supporting data of the other studies, it appears that a dietary MTO inclusion level of .50% optimizes growth, carcass, and meat quality attributes of growing- finishing pigs. Additionally, MTO elicits beneficial responses (reduced weight and fat gain and increased fat-free mass) in a rat model targeted for post-menopausal women.