Effect of diet, sex and age on fatty acid metabolism in broiler chickens : SFA and MUFA

The present study was conducted to evaluate the effect of different dietary lipid sources, age and sex on the SFA and MUFA metabolism in broiler chickens using a whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm; soyabean oil, Soya; linseed oil, Lin; and fish oil, Fish) were added at 3% to a basal diet containing 5% Palm. Diets were fed to female and male chickens from day 1 to either day 21 or day 42 of age. The accumulation (percentage of net intake and <i>ex novo</i> production) of SFA and MUFA was significantly lower in broilers fed on Palm than in broilers fed on the other diets (85·7 <i>v</i>. 97·4 %). Conversely, β-oxidation was significantly higher in Palm-fed birds than the average of the other dietary treatments (14·3 <i>v</i>. 2·6 %). On average, 33·1% of total SFA and MUFA accumulated in the body were elongated, and 13·8% were Δ-9 desaturated to longer chain or more unsaturated metabolites, with lower proportions being elongated and desaturated for the Palm and Fish diets than for the Soya and Lin diets. Total <i>in vivo</i> apparent elongase activity decreased exponentially in relation to the net intake of SFA and MUFA, while it increased with age. Total <i>in vivo</i> apparent Δ-9 desaturase activity was not significantly affected by dietary treatment or age. Total <i>ex novo</i> production and β-oxidation of SFA and MUFA showed a negative and positive curvilinear relationship with net intake of SFA and MUFA, respectively. Sex had no effect on SFA and MUFA metabolism.<br />