Molecular and Cellular Mechanisms of Intramuscular Fat Development and Growth in Cattle

Intramuscular fat, also referred to as marbling fat, is the white fat deposited within skeletal muscle tissue. The content of intramuscular fat in the skeletal muscle, particularly the longissimus dorsi muscle, of cattle is a critical determinant of beef quality and value. In this review, we summarize the process of intramuscular fat development and growth, the factors that affect this process, and the molecular and epigenetic mechanisms that mediate this process in cattle. Compared to other species, cattle have a remarkable ability to accumulate intramuscular fat, partly attributed to the abundance of sources of fatty acids for synthesizing triglycerides. Compared to other adipose depots such as subcutaneous fat, intramuscular fat develops later and grows more slowly. The commitment and differentiation of adipose precursor cells into adipocytes as well as the maturation of adipocytes are crucial steps in intramuscular fat development and growth in cattle. Each of these steps is controlled by various factors, underscoring the complexity of the regulatory network governing adipogenesis in the skeletal muscle. These factors include genetics, epigenetics, nutrition (including maternal nutrition), rumen microbiome, vitamins, hormones, weaning age, slaughter age, slaughter weight, and stress. Many of these factors seem to affect intramuscular fat deposition through the transcriptional or epigenetic regulation of genes directly involved in the development and growth of intramuscular fat. A better understanding of the molecular and cellular mechanisms by which intramuscular fat develops and grows in cattle will help us develop more effective strategies to optimize intramuscular fat deposition in cattle, thereby maximizing the quality and value of beef meat.

Association of polymorphisms in lipid and energy metabolism-related genes with fattening performance in Simmental cattle

Lipid and energy metabolism are major constituents of mammal growth and thus fattening performance of cattle. This study was designed to evaluate the effects of polymorphisms in lipid and energy metabolism-related genes including oxidized low-density lipoprotein receptor 1 (OLR1), lactoferrin (LTF), stearoyl-CoA desaturase (SCD), beta-lactoglobulin (LGB), thyroglobulin (TG), annexin A9 (ANXA9), myogenic factor 5 (MYF5), protein kinase AMP-activated non-catalytic subunit gamma 3 (PRKAG3), and pituitary-specific transcriptional factor 1 (PIT1), on fattening performance in Simmental cattle. A total of 72 purebred Simmental bulls with a similar initial age and weight were fattened on the same farm for 10 months. Association analysis was performed using linear mixed models. The OLR1 marker was significantly associated with the final weight (FW), hot carcass weight (HCW), chilled carcass weight (CCW), dressing percentage (DP), and total weight gain (TWG). SCD affected the FW, TWG, and average daily live weight gain (ADWG). The present results clearly demonstrated the significant impact of the TG marker on fattening performance. It was highly significantly associated with the FW, HCW, CCW, and TWG. The SCD × TG and the OLR1 × TG interactions had remarkable effects on the traits analyzed. The GACC and CCCC haplotypes of the SCD × TG and OLR1 × TG, respectively, were found to be powerful markers for fattening performance in Simmentals. Novel associations in this study may be useful for further genetic evaluations to improve beef cattle breeding.

Electronic Tongue as a Correlative Technique for Modeling Cattle Meat Quality and Classification of Breeds

Discrimination and species identification of meat has always been of paramount importance in the European meat market. This is often achieved using different conventional analytical methods but advanced sensor-based methods, such as the electronic tongue (e-tongue), are also gaining attention for rapid and reliable analysis. The aim of this study was to discriminate Angus, domestic buffalo, Hungarian Grey, Hungarian Spotted cattle, and Holstein beef meat samples from the chuck steak part of the animals, which mostly contained longissimus dorsi muscles, using e-tongue as a correlative technique with conventional methods for analysis of pH, color, texture, water activity, water-holding capacity, cooking yield, water binding activity, and descriptive sensory analysis. Analysis of variance (ANOVA) was used to determine significant differences between the measured quality traits of the five-meat species after analysis with conventional analytical methods. E-tongue data were visualized with principal component analysis (PCA) before classifying the five-meat species with linear discriminant analysis (LDA). Significant differences were observed among some of the investigated quality parameter. In most cases, Hungarian Grey was most different from the other species. Using e-tongue, separation patterns could be observed in the PCA that were confirmed with 100% recognition and 97.5% prediction of all the different meat species in LDA.

Meat quality of Maremmana young bulls

Maremmana is a local Italian breed reared in southern Tuscany and northern Latium. Twenty-two young bulls were reared in pasture system with concentrate supply (PSCS), whereas 20 young bulls were reared in feedlot intensive system (IS) in order test differences between meat typologies. The bulls were slaughtered at 18 months old. The performances at slaughtering were similar between finishing systems. IS bull meat has shown higher cooking loss than PSCS bull meat (p < 0.001), higher moisture content (p < 0.01), and fat (p < 0.001), and lower crude protein (p < 0.001). The SFA, MUFA and PUFA percentage were similar between meat typologies; whereas if considered in mg per 100 gr of muscle MUFA and SFA content was higher in PSCS meat (p < 0.05). Among the Healthy Indices, C18:2/C18:3 was higher in IS System (14.08 vs. 9.77; p < 0.001); the results of the PCA (Principal Component Analysis) of fatty acids composition showed that PSCS meat was characterized by MUFA and SFA, while IS meat was identified by C18:2/C18:3, and ω6/ ω3.