title: Interactive effects of dietary ractopamine HCl and L-carnitine on finishing pigs: II. Carcass characteristics and meat quality.
abstract: Three experiments using 1,356 pigs (C22 × 336 PIC) were conducted to determine the interactive effects of dietary L-carnitine and ractopamine hydrochloride (RAC) on carcass characteristics and meat quality of finishing pigs. Experiments were arranged as factorials with main effects of L-carnitine and RAC; L-carnitine levels were 0, 25, or 50 mg/kg in Exp. 1 and 2 and 0 or 50 mg/kg in Exp. 3, and RAC levels of 0, 5, or 10 mg/kg in Exp. 1 and 0 or 10 mg/kg in Exp. 2 and 3. Dietary L-carnitine was fed from 38 kg to slaughter (109 and 118 kg in Exp. 1 and 3, respectively) or for 4 wk before slaughter (109 kg in Exp. 2). Ractopamine HCl was fed for 4 wk in all experiments. Exp. 1 and 2 were conducted at university research facilities (2 pigs per pen), and Exp. 3 was conducted in a commercial research barn (23 pigs per pen). In Exp. 1, an L-carnitine × RAC interaction (P < 0.02) was observed for LM visual color, L*, and a*/b*. In pigs fed RAC, increasing L-carnitine decreased L* and increased visual color scores and a*/b* compared with pigs not fed RAC. Ultimate pH tended to increase (linear, P < 0.07) with increasing L-carnitine. Drip loss decreased (linear, P < 0.04) in pigs fed increasing L-carnitine. In Exp. 2, firmness scores decreased in pigs fed increasing L-carnitine when not fed RAC, but firmness scores increased and drip losses decreased with increasing L-carnitine when RAC was added to the diet (L-carnitine × RAC interaction, P < 0.04). Percentage lean was greater (P < 0.01) for pigs fed RAC in Exp. 2. In Exp. 3, fat thickness decreased and lean percentage increased in pigs fed L-carnitine or RAC, but the responses were not additive (L-carnitine × RAC interaction, P < 0.03). Furthermore, pigs fed L-carnitine tended (P < 0.06) to have decreased LM drip loss percentage whereas pigs fed RAC had decreased (P < 0.05) 10th rib and average backfat and decreased drip loss than pigs fed diets without RAC. These results suggest that dietary RAC increased carcass leanness and supplemental L-carnitine reduced LM drip loss when fed in combination with RAC.
authors: Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0201, USA.
authors: B W
authors: BW
authors: James
authors: M D
authors: MD
authors: Tokach
authors: R D
authors: RD
authors: Goodband
authors: J L
authors: JL
authors: Nelssen
authors: S S
authors: SS
authors: Dritz
authors: K Q
authors: KQ
authors: Owen
authors: J C
authors: JC
authors: Woodworth
authors: R C
authors: RC
authors: Sulabo
mesh_terms: D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000378:metabolism*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition / Q000187:drug effects*; D002331:Carnitine / Q000008:administration & dosage / Q000378:metabolism*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008460:Meat / Q000032:analysis*; D010627:Phenethylamines / Q000008:administration & dosage / Q000378:metabolism*; D011897:Random Allocation; D034421:Sus scrofa / Q000254:growth & development / Q000502:physiology*; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D000318:Adrenergic beta-Agonists; D010627:Phenethylamines; D014803:Vitamin B Complex; C060897:ractopamine; D002331:Carnitine