Abstract :
The aim of the present study was to evaluate the genetic variation of milk fat CLA, together
with the variation of CLA precursors, including the individual PUFA that are potentially
involved in the metabolic pathway of CLA. The allelic substitution effect, upon these FA,
was estimated for a number of polymorphisms, that are located within 9 candidate genes
known to influence milk FA partitioning. Sheep milk was chosen because it contains higher
total fat percentage, and higher CLA levels per gram fat, than milk of other ruminants. Milk
FAME analyses were performed on individual milk samples of sheep from three different
breeds. Our results reflect the association of three genes (alpha-1-antichymotrypsin; diacylglycerol
O-acyltransferase homolog-2; and zona pellucida glycoprotein-2) with the values
of both linolenic FA and CLA; of three more genes (insulin-like growth factor I; lecithincholesterol
acyltransferase and propionyl coenzyme A carboxylase, beta polypeptide) with
the variability of linolenic FA; and of one gene, the fatty acid synthetase with the variability
of CLA and stearic FA. The current study might contribute to the understanding of
the metabolic pathway of PUFA in sheep milk, providing suggestions to modify milk fat
composition through selection
