linoleic-acid and Hypertrophy

Seventy-five yearling bulls of the "Asturiana de los Valles" northern-Spanish beef breed (double-muscled, mh/mh, n=24; heterozygous, mh/+, n=26; normal, +/+, n=25) were produced under intensive conditions and the effects of double-muscling genotype on trans-18:1 and CLA isomer profiles were examined. Total trans-18:1 contents, measured as percentages of total fatty acid methyl esters, were 10.98-15.07% in backfat and 8.64-9.46% in muscle, and the major isomer was 10t-18:1 in all animals. In mh/+ animals, 11t-18:1 was the second most abundant trans isomer in muscle whereas in mh/mh and +/+ animals 11t-18:1 and 13t/14t-18:1 were relatively similar. Total CLA percentages were 0.71-0.85% in backfat and 0.32-0.40% in muscle. The highest total CLA percentage found was in mh/+, intermediate in +/+ and lowest in mh/mh animals (P<0.05). Heterozygous animals had significantly higher percentages of 9c,11t- (P<0.01), 11t,13c- (P<0.01) and 9c,11c-18:2 (P<0.05) and also significantly higher percentages of the sum of 9c,11t-/11t,13c-/11t,13t-18:2. Overall, mh/+ animals produced meat with a slightly better trans and CLA profile (i.e., less 10t-18:1 and more 11t-18:1 and 9c,11t-18:2) than other genotypes, however, further improvements would still be necessary to achieve a profile with a positive health image.

Topics: Adipose Tissue; Animal Feed; Animals; Cattle; Dietary Fats; Esters; Genotype; Heterozygote; Hypertrophy; Isomerism; Linoleic Acid; Linoleic Acids, Conjugated; Male; Meat; Muscle, Skeletal; Trans Fatty Acids

We have shown that dietary long-chain triglycerides and 16,16-dimethyl prostaglandin E2 enhance and aspirin impairs postresection mucosal adaptation in rats. The present studies examined the hypothesis that supplemental linoleic acid (LA) above the minimum requirement may enhance postresection mucosal adaptation through altered prostaglandin (PG) synthesis. Forty male Sprague-Dawley rats (105 +/- 5 g) were fed purified diet containing either 5% LA or 4% palmitic acid and 1% LA. After 2 weeks, 12 rats from each dietary group underwent 70% proximal jejunoileal resection and the remainder were sham-operated. Dietary regimens were continued for an additional 13 days. Mucosal fatty acid analysis of 1% LA group revealed a ratio of 20:3 n-9/20:4 n-6 lower than 0.2, indicating normal essential fatty acid status. Mucosal protein per centimeter bowel was higher in the 5% LA group compared to the 1% group, but mucosal DNA, maltase, and ex vivo PG synthesis were not affected. These results indicate that LA stimulates postresection mucosal hypertrophy, which does not appear to be related to PG synthesis.

Topics: Adaptation, Physiological; Animals; Dietary Fats; Hypertrophy; Ileum; Intestinal Mucosa; Jejunum; Linoleic Acid; Linoleic Acids; Male; Rats; Rats, Inbred Strains