Effects of overfeeding on the fatty acid profile and stearoyl-CoA desaturase-1 indices in the liver and subcutaneous adipose tissue in cats.

To evaluate the effect of overfeeding on fatty acid distribution and metabolism, especially stearoyl-CoA desaturase-1 (SCD-1) indices, 8 cats in the experimental and control groups (4 per group) were evaluated in this study. The experiments involved feeding the experimental group cats twice their daily energy requirement with a commercial diet for 4 weeks. The control group was fed the estimated daily energy requirement with the same diet. Body weight, feline body mass index, body condition score, several zoometry measurements, and plasma metabolites/hepatic injury markers were measured in all the cats before and after the experiment. In addition, the fatty acid profiles in the liver and subcutaneous adipose tissue were measured after the experiment. After 4 weeks of overfeeding, the experimental group demonstrated significant increases in hepatic C18:1, plasma triglyceride, and nonesterified fatty acid (NEFA) concentrations and in alanine aminotransferase activity. Furthermore, hepatic SCD-1 indices were positively correlated with body weight, feline body mass index, body condition score, and plasma NEFA concentration, although subcutaneous adipose tissue did not demonstrate any increase in SCD-1 indices in this study. The increase in hepatic SCD-1 indices might be enhanced by the inflow of plasma NEFA into the liver, and NEFA toxicity might stimulate C18:1 synthesis by SCD-1.

Estimation of beef marbling in the Longissimus muscle with computer image analysis of ultrasonic pictures of the Iliocostalis muscle area.

This study investigated an objective method for estimating beef marbling using ultrasonic images of the Iliocostalis muscle and the Lomgissimus muscle area sections. Thirty-one Japanese Black cattle steers were used in this study. The end of the left side shoulder blade bone was scanned using an ultrasonic device. Ultrasonic images were captured of the Longissimus muscle area and that around the Iliocostalis muscle area. Twenty items were measured in the two images using computer image analysis software. The level of beef marbling was measured according to the Beef Marbling Standard (BMS) for carcass grading, and the percentage of ether-extractable fat content in the Longissimus muscle (EE). The difference in the gray level between the Iliocostalis muscle and intermuscular fat (X10) was used to estimate the BMS and the EE, which were highly correlated (r(2) = 67.72% and 61.30%). An equation was developed using four parameters from the two ultrasonic images, which could estimate the BMS (r(2) = 85.88%). This equation could also estimate the EE (r(2) = 68.98%). The equations used to estimate beef marbling were based on one to four parameters that included X10. Thus, ultrasonic images of the Iliocostalis muscle area section are important for estimating beef marbling.

The effects of feeding a low level of distiller's dried grains with solubles (DDGS) to yearling Holstein steers.

We examined the effects of feeding a low percentage of distiller's dried grains with solubles (DDGS) to yearling Holstein beef steers during the late stage of the fattening period on growth performance and carcass quality. Fifteen animals were fed a total mixed ration (TMR) feed plus a DDGS supplement equal to 10% of the total feed weight for 3 months (DDGS group). The other 15 animals were fed TMR with no DDGS (Control group). The vitamin E (VE) levels in the blood from the DDGS group showed a tendency to be higher in the DDGS group (P=0.056). Blood urea nitrogen levels in the DDGS group were also higher (P<0.05). The Beef Color Standard (BCS) number for the DDGS group was also higher than that for the Control group (P<0.05). Forty-eight hours after cutting, the yellowness (b*) value for Longissimus muscle in the DDGS group was significantly higher (P<0.05) and the redness (a*) value in the DDGS group tended to be higher than that in the Control group (P=0.05). The study results show a potential for adding value to yearling beef by improving the ability to maintain meat color with an increase in VE content.

Effects of feeding dried distillers grains with solubles (DDGS) on meat quality at the late stage of the fattening period of Holstein steers.

Feeding dried distillers grains with solubles (DDGS) during the late stage of the fattening period of Holstein steers was studied in regard to the influence on meat quality. Sixteen Holstein steers approximately 18 months old were used in this study. Eight animals were fed commercial concentrated feed for the entire fattening period. The other eight animals were fed 15% DDGS in the concentrated feed for 3 months before slaughtering. The moisture, ether extract and crude protein from both groups was approximately the same. The thiobarbituric acid reactive substance (TBA) value of storage for 7 days at 5°C from the animals fed DDGS showed a tendency to be lower (P = 0.059). The change in the TBA value during storage was also lower for the animals not fed DDGS (P < 0.05). There were no differences in the subcutaneous fat color between the two groups. The a*(measure of redness) and b*(measure of yellowness) of the M. longissimus from the animals fed DDGS showed a tendency to be lower (P = 0.051, 0.070). The fatty acid composition of the M. longissimus, subcutaneous and perirenal fat were not widely influenced by the feeding of DDGS. It is suggested that feeding 15% DDGS during the late stage of the fattening period for Holstein steers reduced the oxidation of the beef.

Relationship between adipose maturity and fatty acid composition in various adipose tissues of Japanese Black, Holstein and Crossbred (F1) steers.

The amount of monounsaturated fatty acid (MUFA) is intimately related to adipose softness, melting point (MP) and flavor in beef. Stearoyl-CoA desaturase (SCD) is a main gene involved in MUFA synthesis. Mature adipose tends to be highly saturated, whereas immature or maturing adipose is highly unsaturated when chronologically based, so the degree of non-saturation can be an index of adipose maturity. In this study, three different adipose tissues (coelomic (CL), perirenal (PR), and subcutaneous (SC)) from three beef breeds with differing slaughter ages (Japanese Black (29.5 months), Holstein (20.1 month), and F1 crossbreed (25.6 months)) were examined to: (i) determine adipose maturity level as indexed by MUFA %; and (ii) determine SCD and other lipogenic gene messenger RNA (mRNA) expression levels in relation to unsaturated fatty acid content. Fatty acid composition was significantly different between adipose tissues (P < 0.05). MUFA amount was high in the following order: SC > CL > PR. This pattern corresponded to SCD mRNA expression profile showing higher expression in SC than CL and PR. However, Japanese black cattle are an exception with CL adipose containing similar UFA % as SC adipose, yet having the lowest SCD mRNA expression level among all adipose tissues tested. Therefore, SCD mRNA expression and MUFA % appear to be directly related; however, differences in SCD mRNA expression among three adipose tissues may reflect differences in the fat development characteristics affected by chronological age of the cattle breeds.

Novel mutations of the FASN gene and their effect on fatty acid composition in Japanese Black beef.

Eight novel and four known mutations were detected in the coding sequence of the bovine fatty acid synthase (FASN) gene of an F2 population from Japanese Black and Limousin cattle. Two mutations, g.16024A>G and g.16039T>C, detected in exon 34, which determine amino acid substitutions of threonine (T) to alanine (A) and tryptophan (W) to arginine (R), were clearly separated in the parental breeds. The haplotypes (TW and AR) segregated in F2 individuals and had a significant effect on the fatty acid composition of backfat, intermuscular fat, and intramuscular fat. The TW haplotype was associated with increasing C18:0 and C18:1 content and the ratio of monounsaturated to saturated fatty acids, and decreasing C14:0, C14:1, C16:0, and C16:1 content. The two mutations were screened in two commercial Japanese Black half-sibling populations and similarly determined the contribution to the fatty acid composition of intramuscular fat. The frequency of the TW haplotype was markedly higher in Japanese Black (0.67) than in Holstein (0.17), Angus (0.02), and Hereford (0.07). We conclude that these mutations may contribute to the characteristic fatty acid composition of Japanese Black beef.