ABSTRACT
The primary objective of this study was to determine the effect of long-term feeding of whole cottonseed (WCS) on lipogenesis and stearoyl-coenzyme A desaturase activity in growing steers. Brangus steers were fed either a control, cornbased diet (n = 11) or 30% WCS (n = 12). The 30% WCS contributed an estimated 6.6% additional lipid to the diet. Steers fed the added WCS had greater live weights (P = 0.04) and kidney, pelvic, and heart fat (P = 0.005). Subcutaneous fat thickness was not different (P = 0.20) between treatment groups, although WCS elicited an increase in the proportion of large diameter subcutaneous adipocytes. The rate of [U-14C]acetate incorporation into fatty acids in subcutaneous adipose tissue was reduced by dietary WCS (171.4 vs 122.1 nmol x 100 mg adipose tissue-1 x 2 hr-1, P = 0.03), indicating that the increased dietary fat depressed de novo lipogenesis. Hepatic desaturase activity was much lower than that of subcutaneous adipose tissue, a feature common to cattle. We anticipated that added WCS also would depress stearoyl-coenzyme A desaturase activity in subcutaneous adipose tissue and liver due to its cyclopropene fatty acid content. Instead, desaturase activity was numerically (although not significantly) greater in liver (P = 0.37) and adipose tissue (P = 0.23).
Subject(s)
Adipose Tissue/drug effects , Adipose Tissue/metabolism , Cottonseed Oil/administration & dosage , Lipids/biosynthesis , Stearoyl-CoA Desaturase/metabolism , Adipose Tissue/anatomy & histology , Animals , Cattle , Depression, Chemical , Liver/drug effects , Liver/enzymology , Male , Organ Size/drug effectsABSTRACT
Angus (n = 10) and crossbred (3 4 and 7 8 ) Wagyu (n = 10) steers were fed a diet according to typical Japanese standards for 552 days. The steers were fed to gain approximately 0·90 kg/head/day. Fatty acid composition was determined for subcutaneous and intramuscular adipose tissue, and M. longissimus dorsi muscle. Trained sensory evaluation and a consumer triangle test were performed on M. longissimus dorsi muscle steaks. For subcutaneous and intramuscular tissue. Wagyu adipose tissue possessed higher (P < 0·05) percentages of 14:1, 16:1 and 18:1 and a lower (P < 0·05) percentage of 16:0 and 18:0 than corresponding tissues from Angus steers. Trained sensory panel analysis revealed no differences (P < 0·05) in any of the sensory traits between steaks from Wagyu crossbred and Angus steers. However, a consumer triangle test indicated that consumers can detect a difference between breeds.
ABSTRACT
Three experiments were conducted to document the fatty acid composition of tissues from purebred Wagyu cattle from Japan and North American crossbred Wagyu. In experiment 1, subcutaneous (s.c.) adipose tissues (n = 23) were obtained from Japanese cattle representing the five Japanese fat quality grades. The monounsaturated:saturated fatty acid ratio (MUFA:SFA) was greatest in fat quality grade 5 samples (2·57) and least in the fat quality grade 3 samples (2·08; P < 0·05). In experiment 2, M. longissimus dorsi and the associated intramuscular (i.m.) and s.c. adipose tissues were obtained from carcasses of Wagyu crossbred steers (1/2-7/8) raised in the USA. Fatty acid composition varied among depots, but the MUFA:SFA ratio in s.c. adipose tissue (1·46) was not different from values reported for other breeds of cattle. In experiment 3, samples of M. longissimus dorsi ribsteaks were obtained from three regions in Japan. Samples from the Gunma region had the greatest (P < 0·05) MUFA:SFA ratio (2·10), relative to samples from the Kagoshima (1·82) and Miyazaki (1·65) regions. The data indicate that beef from purebred Wagyu cattle raised in Japan is enriched in monounsaturated fatty acids, and that the degree of enrichment depends upon the region of Japan from which the samples were obtained.
