Total lipid from feed material was extracted according to AOAC
(2005)procedures for the determination of fats. Total lipid from muscle
samples was quantitatively extracted, according to the method of Folch,
Lees, and Stanley (1957), using chloroform and methanol in a ratio of
2:1, butylated hydroxytoluene was added at a concentration of 0.001%
to the chloroform:methanol mixture. A rotary evaporator was used to
dry the fat extracts under vacuum and the extracts were dried overnight in a vacuum oven at 50 °C, using phosphorus pentoxide as a moisture adsorbent. Total extractable intramuscular fat was determined gravimetrically from the extracted fat and expressed as percent fat
(w/w) per 100 g tissue. The extracted fat from feed and muscle was
stored in a polytop (glass vial, with push-in top) under a blanket of
nitrogen and frozen at−20 °C pending fatty acid analyses