The effect of conjugated linoleic acid supplementation on lipid profile and body composition of healthy growing wistar rats. / O efeito da suplementação com acido linoleico conjugado sobre o perfil lipidico e a composição corporal em ratos wistar saudaveis em crescimento.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Conjugated linoleic acid (CLA), a group of positional and geometric isomers of linoleic acid with conjugated double bonds, occurs in small quantities in a wide variety of foods. CLA can originate in the rumen by biohydrogenation of fatty acids from ingested food, and by the desaturation of the trans-11 C18:1 fatty acid. Thus, significant concentrations of CLA are found in beef, milk and dairy products. The purpose of this study was to assess the effect of conjugated linoleic acid supplementation on lipid profile and body composition of healthy growing Wistar rats. Two biological assays were performed: one varying CLA supplement concentration in the diet, and another varying the commercial brands of CLA used. For the first assay, 40 albino male, weaning rats were distributed at random in 4 groups of 10 animals each, according to the amount of supplement to be administered. Animals in groups AE1, AE2 and AE4 were supplemented daily for 21 days with the commercial product AdvantEdge® CLA (EASTM) at 1, 2 and 4 % of food intake respectively, and those in group C (control) with linoleic acid at 2% of food intake. The aim of this first assay was to find the optimum amount of supplement for the purpose of body fat reduction. In the second assay, 30 albino male, weaning Wistar rats were distributed at random in 3 groups of 10 animals each, according to the brand of supplement. Animals were supplemented daily for 42 days at a concentration of 2 %, chosen on the basis of results in the previous assay. Group AE received AdvantEdge® CLA (EASTM); group CO was fed CLA One® (Pharmanutrients); and group C (control) was given linoleic acid at 2 % of food intake. Throughout the experimental period animals had their weight and food intake controlled every 2 days. At the end of each experiment, the animals were killed by cervical displacement under anesthesia (sodium pentobarbital . 46 mg/kg). The blood was used for the determinations of serum triacylglycerols, total cholesterol and leptin; and the carcass was used for determining body composition. Gut contents were removed to obtain empty carcass weight. The carcass was then frozen in liquid nitrogen, chopped, dried, ground and stored at - 80 °C until determinations of water, ash, protein and fat were performed. Feeding efficiency of the rats was not altered by CLA supplementation in either of the assays. No significant difference (p >0.05) was observed in the serum levels of triacylglycerols after supplementation with CLA. Total cholesterol values, as measured in the first essay after 21 days of treatment, presented a dose-dependent reduction. In the second assay, however, CLA supplementation was found to increase total cholesterol after 42 days. An average reduction of 18.0 % on body fat percentage was found in groups AE2 (11.2 %) and AE4 (11.6 %), compared to the control (13.9 %). Body fat percentage was also reduced by 18.0 % in the second assay in groups AE and CO, compared to the control (18.1 %, 16.7 % e 21.2 %, respectively). After 42 days of CLA supplementation, animals in groups AE and CO, in the second assay, displayed an increase of 7.5 % in ash content and a decrease of 22.4 % in the serum leptin concentration. Considering the results obtained it can be concluded that the conjugated linoleic acid supplementation at a concentration of 2 % of food intake reduced the body fat and increased the ash content of rats.

ASSUNTO(S)

nutrição satty acids rats lipids lipidios - analise nutrition rato corpo - composição acidos graxos body composition

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