Liver metabolic changes induced by conjugated linoleic acid in calorie-restricted rats

ABSTRACT Objective Complexes like conjugated linoleic acid (CLA) reduce the percentage of body fat by increasing energy expenditure, fat oxidation, or both. The aim of this study was to verify if CLA is able to mimic caloric restriction (CR), and determine the effects of CLA on liver metabolic profile of young adult male Wistar rats. Materials and methods We divided 36 animals into the following groups: 1) Control; 2) CLA (1% of daily food intake, 21 days, orogastric intubation); 3) Restr (fed 60% of the diet offered to controls); and 4) CLA Restr. Liver tissues were processed for biochemical and molecular or mitochondrial isolation (differential centrifugation) and blood samples were collected for biochemical analyses. Results Treatment of the animals for 21 days with 1% CLA alone or combined with CR increased liver weight and respiration rates of liver mitochondria suggesting significant mitochondrial uncoupling. We observed a decrease in adipose tissue leading to insulin resistance, hyperinsulinemia, and hepatic steatosis due to increased liver cholesterol and triacylglycerol levels, but no significant effects on body mass. The expression of hepatic cellular connexins (43 and 26) was significantly higher in the CLA group compared with the Control or Restr groups. Conclusion CLA does not seem to be a safe compound to induce mass loss because it upregulates the mRNA expression of connexins and induces hepatic mitochondrial changes and lipids disorders.

Manipulation of the fatty acids composition of poultry meat and giblets by dietary inclusion of two oil sources and conjugated linoleic acid / Mudança na composição de ácidos graxos das vísceras e da carne de aves tratadas com uma dieta contendo ácido linoléico conjugado e duas fontes de óleo

The effect of dietary conjugated linoleic acid (CLA) in association with two vegetable oil sources on the fatty acids of meat and giblets of broiler chickens was evaluated. Two hundred 21-day-old broiler chickens were distributed in a completely randomized factorial design 2 x 5 (two oil sources, soybean or canola oil; and five levels of CLA, 0.0, 2.5, 5.0, 7.5, and 10.0g/kg). The addition of CLA to the diet resulted in an increase (P<0.05) in CLA deposition in the analyzed tissues. CLA supplementation also reduced (P<0.05) the rate of polyunsaturated to saturated fatty acids in thigh, breast, heart, and gizzard. There was interaction of CLA x oil source (P<0.05). The intake of soybean oil, associated with increasing CLA, resulted in an increase in lipid deposition in edible portions as observed by an increase in the overall content of fatty acids, including CLA, while the use of canola oil, associated with increasing CLA in the diet, resulted in a decrease in lipid content in edible portions, specifically regarding that of saturated fat (P<0.05) in breast meat and liver and in the content of monounsaturated fatty acids (P<0.05) in thigh, breast, liver, and gizzard.

Avaliou-se o efeito da suplementação de ácido linoléico conjugado (CLA) associado com duas fontes de óleo na dieta de frangos de corte sobre a composição de ácidos graxos das vísceras e da carne de aves. Duzentos frangos de corte, machos, com 21 dias de idade, foram distribuídos em delineamento inteiramente ao acaso, em arranjo fatorial 2 x 5 (duas fontes de óleo, soja e canola e cinco níveis de CLA, 0,0, 2,5, 5,0, 7,5 e 10,0g/kg). A adição de CLA na dieta resultou em aumento (P<0,05) de sua deposição na carne e nas vísceras de aves. Foi observado decréscimo (P<0,05) na taxa de poliinsaturados:saturados nas carnes da coxa e do peito, no coração e na moela com a suplementação de CLA. Houve interação (P<0,05) CLA x fonte de óleo. O uso de teores crescentes de CLA na dieta contendo óleo de soja na dieta resultou em aumento (P<0,05) no conteúdo lipídico. O contrário foi verificado com a utilização de óleo de canola, especificamente no conteúdo de ácidos graxos saturados (P<0,05) na carne do peito e no fígado e de monoinsaturados (P<0,05) nas carnes do peito e da coxa, fígado e moela.

Conjugated linoleic acid supplementation modified the body composition and serum leptin levels in weaning rats

Dietary supplementation with conjugated linoleic acid (CLA) may reduce body fat mass and increase lean body mass in various species. The objective of this study was to study the effects of conjugated linoleic acid (CLA) supplementation on body composition, serum leptin and triacylglycerol levels in Wistar rats. Rats received linoleic acid (group C) or conjugated linoleic acid (group AE, supplemented with AdvantEdge® CLA, and group CO, supplemented with CLA One®) in the concentrations of 2% of daily feed consumption. Serum leptin and triacylglycerol levels of rats were measured by means of commercial kits. After 42 days of supplementation, rats in the control group exhibited body fat contents of 53.94 ± 6.80 g, and those in groups AE and CO had 45.43 ± 4.86 g and 43.75 ± 1.93 g, respectively, corresponding to a mean body fat reduction of 18%. Water, whole body protein and ash contents of rats supplemented with CLA were statistically higher relative to control group content (corresponding to a mean increasing of 7.65%; 6.5% and 12.35%, respectively). Experimental groups AE and CO, which received CLA supplementation, had statistically lower serum leptin levels (3.45 ± 0.46 ng/mL and 3.08 ± 0.19 ng/mL, respectively) relative to the control group (4.21 ± 0.22 ng/mL) which received linoleic acid. Triacylglycerol levels did not change after CLA supplementation (p > 0.05). Supplementation with conjugated linoleic acid in the concentration of 2% of mean daily feed consumption was able to change body composition of rats after 42 days of experimentation.

La suplementación con ácido linoléico conjugado modificó la composición corporal y los niveles séricos de leptina en ratas recién destetadas. El objetivo de este trabajo fue estudiar los efectos del suplemento con ácido linoléico conjugado (CLA) sobre la composición corporal, leptina en suero y niveles de triacilglicerol en ratas Wistar. Las ratas recibieron ácido linoléico (grupo C) o ácido linoléico conjugado (grupo AE, suplementado con AdvantEdge® CLA, y grupo CO, suplementado con CLA One®) en una concentración de 2% del consumo diario de alimentación. Los niveles de leptina en suero y triacilglicerol de las ratas fue medido por medio de kits comerciales. Después de 42 días de suplementación, las ratas del grupo de control exhibieron contenidos de grasa corporal de 53.94 ± 6.80 g, y los de los grupos AE y CO tuvieron 45.43 ± 4.86 g y 43.75 ± 1.93 g, respectivamente, lo que corresponde a una reducción media de la grasa corporal del 18%. El agua, la proteína corporal total y el contenido de cenizas de las ratas suplementadas con CLA fueron estadísticamente superiores en relación al contenido del grupo control (lo que corresponde a un aumento medio de 7.65%; 6.5% y 12.35%, respectivamente). Los grupos experimentales AE y CO, que recibieron suplementación con CLA, tuvieron niveles de leptina en suero estadísticamente menores (3.45 ± 0.46 ng/mL y 3.08 ± 0.19 ng/mL, respectivamente) en relación al grupo control (4.21 ± 0.22 ng/mL) que recibió ácido linoléico. Los niveles de triacilglicerol no cambiaron después del suplemento con CLA (p > 0,05). La suplementación con ácido linoléico conjugado en una concentración de 2% del promedio del consumo diario de alimento fue capaz de cambiar la composición corporal de las ratas después de 42 días de experimentación.