Effects of somatotropin and salbutamol in three genotypes of finishing barrows: growth, carcass, and calorimeter criteria.
We evaluated the combined use of 0 or 4 mg/d of recombinant porcine somatotropin (pST) and 0 or 2.75 ppm salbutamol in three genotypes of growing barrows (139 d old) differing in lean and lipid accretion potential. Treatments were in a 2 x 2 x 3 factorial arrangement, and the three genotypes tested were Meishan (M, n = 32, 49 kg), Duroc x White composite (D x Wc, n = 31, 62 kg), and Meishan x White composite (M x Wc, n = 31, 64 kg) pigs. Growth performance was evaluated over 28 d for individual pigs, and 20-h feed-deprived heat production was measured before slaughter (d 34). Daily pST injection increased ADG (+70 g/d) and reduced ADFI (-.61 kg/d) across genotypes (P < .05). Salbutamol increased (P < .05) ADG in M x Wc pigs (+146 g/d) but not in M pigs (-60 g/d) or D x Wc (+80 g/d) pigs. However, M pigs had the lowest ADG and ADFI, and M x Wc pigs not treated with salbutamol grew slower than D x Wc pigs (P < .05). Carcass protein and moisture accretion were additively (P < .05) increased by pST and salbutamol for D x Wc and M x Wc pigs. Meishan pigs had increased carcass protein and moisture accretion from pST, whereas only moisture accretion was increased by salbutamol (P < .05). The longissimus muscle area and semitendinosus weight increased as the percentage of M in the genotype decreased (P < .05), and both were increased by pST or salbutamol treatment (P < .001). Leaf fat was decreased more (P < .05) in M pigs than in D x Wc or M x Wc pigs with pST injection. The similar magnitude of leaf fat reduction between D x Wc and M x Wc pigs resulted in a mean genotype difference (P < .05), and salbutamol decreased leaf fat across genotypes. Oxygen consumption and heat production were increased by pST in M pigs more than in the crossbred genotypes, but CO2 production was reduced by similar magnitudes across genotypes, and salbutamol only tended to reduce CO2 production in D x Wc pigs. In general, these data indicate that pST and salbutamol result in additive increases in carcass lean composition; however, growth rate, carcass accretion, and various organ weights may vary among genotypes with salbutamol and pST treatment.
Hansen
J A
JA
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-0201, USA.
Yen
J T
JT
Nelssen
J L
JL
Nienaber
J A
JA
Goodband
R D
RD
Wheeler
T L
TL
D000420:Albuterol / Q000494:pharmacology*; D000818:Animals; D001823:Body Composition / Q000187:drug effects / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002153:Calorimetry, Indirect / Q000379:methods / Q000662:veterinary; D002245:Carbon Dioxide / Q000378:metabolism; D004338:Drug Combinations; D004435:Eating / Q000502:physiology; D005838:Genotype; D013006:Growth Hormone / Q000494:pharmacology*; D050356:Lipid Metabolism; D008297:Male; D008460:Meat / Q000592:standards*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000502:physiology; D013552:Swine / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology
D001993:Bronchodilator Agents; D004338:Drug Combinations; D018377:Neurotransmitter Agents; D002245:Carbon Dioxide; D013006:Growth Hormone; D000420:Albuterol