Conjugated linoleic acid decreases fat accretion in pigs evaluation by dual-energy X-ray absorptiometry

Abstract

Thirty female Large White &times; Landrace pigs (average weight 57&middot;2 (SD 1&middot;9) kg) were allocated to one of six dietary treatments containing 0, 1&middot;25, 2&middot;5, 5&middot;0, 7&middot;5 or 10&middot;0 g 55 % conjugated linoleic acids (CLA) isomers (CLA-55)/kg diet and fed for 8 weeks. Each pig was scanned at 0, 28 and 56 d and again at post slaughter using dual-energy X-ray absorptiometry (DXA) to determine the temporal pattern of body composition responses. Values determined by DXA were adjusted using regression equations generated from validation experiments between chemically and DXA-predicted values. Overall, there was a significant linear reduction in fat content with the increasing levels of CLA in the diet (P=0&middot;007, P=0&middot;011, P=0&middot;008 at week 4, week 8 and for the carcass, respectively). The greatest improvement was recorded at the early stages of CLA supplementation and for the highest dose of CLA (week 4, -19&middot;2 % compared with week 8, -13&middot;7 %). In the first 4 weeks of feeding CLA, pigs receiving 10 g CLA-55/kg diet deposited 93 g less fat/d than pigs fed basal diets (P=0&middot;002) compared with only 6 g less fat than control animals in the final 4 weeks. Lean content and lean deposition rate were maximised at 5 and 2&middot;5 g CLA-55/kg diet for the first 4 weeks (P=0&middot;016) and the final 4 weeks of treatment (P=0&middot;17), respectively. DXA estimates of bone mineral content and bone mineral density were not affected by CLA supplementation throughout the experiment. These data demonstrate that dietary CLA decreases body fat in a dose-dependent manner and that the response is greatest over the initial 4 weeks of treatment.<br /