Effect of dietary linseed supplements on ù-3 PUFA content and on IGF-1 expression in broiler tissues

The aim of this study was to evaluate the effect of ù-3 PUFA-rich linseed-supplemented diet on the ù-6/ù-3 PUFA content and IGF-I mRNA expression in broiler tissues. Broilers (50 of 21 d old and 90 of 42 d old) were divided into groups according to dietary additives: 1.5% linseed oil (LO), 3.0% LO, 15% linseed cake (LC) and 30% LC and to the duration of modified feeding (1 21, 1 42 and 22 42 days). PUFA content in breast muscles was assayed by gas chromatography and IGF-I mRNA content in liver, muscle and leukocytes was measured by one step RT-PCR. The experimental diets improved the ù-6/ù-3 PUFA ratio through a threefold increase in the ù-3 PUFA content in the breast muscle. The changes in PUFA content were accompanied by changes in IGF-1 gene expression levels in tissues. Therefore, both paracrine and autocrine manner of IGF-1 action are likely to be involved. 15% LC at starting period or 1.5% LO in final diet can be advised as optimal for enriching broiler meat with ù-3 fatty acids.