Interrelationships between sex and ractopamine on protein and lipid deposition in rapidly growing pigs.
Sixty pigs were used to investigate the effects of two levels of dietary ractopamine (RAC; 0 and 20 mg/kg) and three sex types (SEX; boars, gilts, and barrows) on performance over the live weight range 60 to 90 kg. Pigs were housed in individual pens and allowed ad libitum access to a diet containing 3.466 Mcal of DE and 10.7 g of lysine/kg. Control boars exhibited faster and more efficient growth and deposited more protein and less fat than gilts or barrows. The RAC increased ADG by 17 and 21% in gilts and barrows but not in boars. Feed intake was not altered by dietary RAC. Dietary RAC increased the rate of protein deposition by 15, 42, and 41% in boars, gilts, and barrows, respectively. Nevertheless, the daily rate of protein deposition was greatest in RAC-treated boars. The RAC tended to reduce the daily rate of fat deposition by 21% in boars but not in gilts or barrows. Carcass protein content increased by 5% and fat content decreased by 8% in response to RAC. These improvements in carcass composition occurred without compromising meat quality. Results show that RAC is a potent stimulator of protein deposition in finishing pigs. However, increased protein deposition is not necessarily at the expense of fat deposition.
Dunshea
F R
FR
Department of Agriculture, Victorian Institute of Animal Science, Werribee, Australia.
King
R H
RH
Campbell
R G
RG
Sainz
R D
RD
Kim
Y S
YS
D000273:Adipose Tissue / Q000254:growth & development; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005260:Female; D006133:Growth Substances / Q000008:administration & dosage / Q000494:pharmacology*; D050356:Lipid Metabolism; D008297:Male; D008460:Meat / Q000592:standards; D024510:Muscle Development; D009919:Orchiectomy / Q000662:veterinary; D009929:Organ Size / Q000187:drug effects; D010627:Phenethylamines / Q000008:administration & dosage / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D012727:Sex Characteristics; D013552:Swine / Q000254:growth & development* / Q000378:metabolism; D015430:Weight Gain / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D006133:Growth Substances; D010627:Phenethylamines; D011506:Proteins; C060897:ractopamine