Effect of sunflower seed supplementation on the fatty acid composition of muscle and adipose tissue of pasture-fed and feedlot finished cattle.

摘要

Effects of feeding whole sunflower seeds (WSS) to cattle on pasture and during finishing were investigated upon the fatty acid composition of their beef (gastrocnemius, longissimus thoracis, intercostals) and adipose tissues (subcutaneous and intermuscular). 96 yearling males (average wt. 410 kg) were divided among the following pasture (P) treatments: P + WSS; P + cracked barley grain; and non-supplemented P (control). They rotationally grazed meadow bromegrass-alfalfa pasture for 66 days, after which half the cattle from each treatment group were moved to a feedlot and adjusted to finishing diets. The remaining cattle continued their dietary treatments on stockpiled pasture for a further 47 days, before being slaughtered directly off pasture. In the feedlot, half the cattle from each treatment group were fed a control diet (83% rolled barley, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral mix) and half were fed a WSS-supplemented diet (68% rolled barley, 15% WSS, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral mix). Provision of WSS to cattle on pasture for 113 days, followed by direct slaughter, increased beef and adipose tissue cis-9, trans-11 CLA contents by 17.0-29.1 and 32.0-40.3%, respectively. Contents of C18:1 trans-11 in the beef and intermuscular adipose tissue were also increased by 20.1-40.8 and 55.0%, respectively. Inclusion of WSS in finishing feeds increased CLA cis-9, trans-11 content by 31.5-209.0% in beef and by 25.6-40.7% in the adipose tissues. Corresponding increases in C18:1 trans-11 content were 80.0-207.3 and 181-224%. Strong, positive relationships were observed between tissues in the concn. of CLA cis-9, trans-11, C18:1 trans-11 and C18:3 (R2, 0.69-0.88; P < 0.0001). Results indicate that increasing the level of PUFA in cattle diets may increase levels of CLA cis-9, trans-11 and C18:1 trans-11 in beef and adipose tissues.