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Title: CHANGES IN BODY COMPOSITION WHEN YOUNG PIGS ARE RESTRICTED TO NEAR MAINTENANCE DIETARY INTAKE

Author
item Mitchell, Alva
item SCHOLZ, A. - UNIVERSITY OF MUNICH
item PURSEL, V. - ARS, BGL RETIRED

Submitted to: International Journal of Body Composition Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2003
Publication Date: 9/1/2003
Citation: Mitchell, A.D., Scholz, A.M., Pursel, V.G. 2003. Changes in body composition when young pigs are restricted to near maintenance dietary intake. International Journal of Body Composition Research. 1(3):123-128.

Interpretive Summary: When adult animals are fed at maintenance intake, no change in body weight or composition would be expected. However, when young normally growing animals are subjected to maintenance intake, changes in body composition are likely to result. Dual energy X-ray absorptiometry (DXA) was used to measure the body composition of pigs before and after an eight-week period during which they were fed only enough to maintain body weight. During this time, pigs that were not restrictively fed (controls) gained 49 kg, consisting of 17 kg of fat and 32 kg of lean. By comparison the restricted pigs gained 5 kg of lean, but lost 0.8 kg of fat. Relative to the initial measurement, the fat content of the restricted pigs decreased by 7.5% while that of the ad libitum fed pigs increased by 151%. As a percentage of total body weight, the bone mineral content increased in the restricted pigs, but decreased in the control pigs. These results provide a model for changes in body composition during restricted growth that might occur as a result of malnutrition or disease.

Technical Abstract: The purpose of this study was to investigate the changes in body composition that occur when young-rapidly growing animals are subjected to an acute period of restricted dietary intake that results in little or no change in body weight. At 60 kg, a total of 74 pigs were scanned by dual-energy X-ray absorptiometry (DXA). Subsequently, 49 pigs were restrictively fed to maintain body weight and 25 pigs were fed ad libitum. After 56 days all pigs were again scanned by DXA. During the 56-day study restricted pigs gained only 4.3 ± 0.5 kg while the pigs on ad libitum intake gained 49.9 ± 0.4 kg. DXA analysis revealed that during this time, the restricted pigs lost 0.78 ± 0.15 kg of body fat while gaining 4.9 ± 0.5 kg of lean and 160 ± 20 g of bone mineral (BMC). Bone mineral density (BMD) decreased slightly (-0.01 g/cm²). By comparison, the ad libitum fed pigs gained 16.8 ± 0.5 kg of fat, 32.4 ± 0.5 kg of lean and 679 ± 30 g of BMC, and BMD increased by 0.18. Relative to the initial measurement, the fat content of the restricted pigs decreased by 7.5% while that of the ad libitum fed pigs increased by 151%. As a percentage of total body weight, the BMC increased in the restricted pigs, but decreased in the ad libitum fed pigs. These results provide a model for changes in body composition during restricted growth that might occur as a result of malnutrition or disease.