Submitted to: OECD Workshop - Practical and Innovative Measures for the Control of Agricu
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2000
Publication Date: 12/31/2004
Citation: Pursel, V. G., Mitchell, A. D. Wall, R. J., Solomon, M. B., Coleman, M. E. and Schwartz, R. J. (2001). Transgenic research to enhance growth and lean carcass composition in swine. In: Molecular Farming. J. P. Toutant and E. Balazs, Eds. pp. 77-86. Proceedings OECD Conference on Molecular Farming. INRA Editions, Paris. (Proceedings Book). Interpretive Summary:
Technical Abstract: Although growth hormone is considered the primary growth-promoting hormone in mammals, many of its effects are mediated by insulin-like growth factor-I (IGF-I). Founder transgenic pigs were produced with a fusion gene composed of avian skeletal alpha-actin regulatory sequences and a cDNA encoding IGF-I. For the study reported here one transgenic boar was mated to non-transgenic gilts to produce sibling transgenic (TG) and control (CT pigs. Daily gain did not differ for TG and CT pigs up to 90 kg, then the TG pigs gained significantly faster. At 90 and 120 kg, pigs were anesthetized and scanned by dual-energy x-ray absorptiometry (DXA) to estimate fat and lean composition. Between the first and second DXA scans, the rates of lean tissue accretion was 30.3 and 31.6 % higher, and conversely, rates of fat accretion were 20.7 and 23.7 % lower in TG gilts and barrows than in CT pigs. Pigs were sacrificed the day after the second dDXA scan, the right half of each carcass was scanned by DXA, and measurements were taken. Transgenic gilts and barrows, respectively, had 36 and 29% larger loin eye areas, 9 and 12% more carcass lean tissue, and 18 and 23% less total carcass fat than CT pigs (P < .001, for each). Individual muscles dissected from the left carcass half were significantly heavier for the TG pigs than for CT pigs. Our results confirm our earlier findings that the targeting of IGF-I expression to striated muscles clearly had a major impact on carcass composition.