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The aim of this study was to evaluate the non-carcass components (NCC) of Berganês ecotype lambs of different sexual classes and genotypes using univariate and multivariate statistics, carrying out two experimental trials. In order to evaluate the effects of the sexual class, non-castrated males (BNC), castrated males (BC) and females (BF) of Berganês ecotype lambs were used, with mean initial body weight of 27 ± 3.1 kg. To evaluate crossbreeding, non-castrated male lambs of the genotypes Berganês (BG), Berganês × Santa Inês (BSI) and Berganês × Dorper (BD) were used, as well as the control Dorper × Santa Inês (DSI), all with mean initial body weight of 28 ± 3.8 kg. The weight and yield of the total by-products was higher for BNC. Regarding the genotype, BSI showed higher weight and yield of internal fat, but the weight and yield of the total by-products was higher for BG and BD. In factorial analysis (FA), the NCC, more correlated with empty body weight (EBW) and total weight gain (TWG), showed higher eigenvectors for factor 1. For factor 2, the weights and yields of internal fat and total viscera obtained higher eigenvectors. The discriminant analysis (DA) classified 100% of individuals in their respective sexes and genotypes. Therefore, the FA indicated that, among the NCC evaluated, the weights of liver, kidneys, GIT, skin and feets are determinant for obtaining EBW and TWG. The classification achieved by the DA indicates that the sexual classes and genotypes are heterogeneous. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of sex on carcass yield and meat quality of guinea pig (Cavia porcellus). Twenty animals (10 males and 10 females) Criollos, with initial body weight of 286 ± 4.26 g and 2 months of age were distributed in a completely randomized design. The guinea pigs fed a diet based on vegetables and concentrate in a roughage:concentrate ratio of 80:20. After 60 days, animals were slaughtered and their carcasses and meat were evaluated. Males had higher slaughter weight, total weight gain, hot carcass weight, cold carcass weight, cold carcass yield, meat weight, meat yield, leg weight, loin + flank weight and front weight (P < 0.05). Females showed higher carcass chilling loss, liver yield, cooking loss and protein and ash content in meat (P < 0.05). The use of male guinea pigs for meat production provides higher yields of carcasses, meat and commercial cuts, and lower losses during carcass chilling and meat cooking. [ABSTRACT FROM AUTHOR]

Proteins are the major constituents of muscle and are key molecules regulating the metabolic changes during conversion of muscle to meat. Brazil is one of the largest exporters of beef and most Brazilian cattle are composed by zebu (Nellore) genotype. Bos indicus beef is generally leaner and tougher than Bos taurus such as Angus. The aim of this study was to compare the muscle proteomic and phosphoproteomic profile of Angus and Nellore. Seven animals of each breed previously subjected the same growth management were confined for 84 days. Proteins were extracted from Longissimus lumborum samples collected immediately after slaughter and separated by two-dimensional electrophoresis. Pro-Q Diamond stain was used in phosphoproteomics. Proteins identification was performed using matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Tropomyosin alpha-1 chain, troponin-T, myosin light chain-1 fragment, cytoplasmic malate dehydrogenase, alpha-enolase and 78 kDa glucose-regulated protein were more abundant in Nellore, while myosin light chain 3, prohibitin, mitochondrial stress-70 protein and heat shock 70 kDa protein 6 were more abundant in Angus (P<0.05). Nellore had higher phosphorylation of myosin regulatory light chain-2, alpha actin-1, triosephosphate isomerase and 14-3-3 protein epsilon. However, Angus had greater phosphorylation of phosphoglucomutase-1 and troponin-T (P<0.05). Therefore, proteins involved in contraction and muscle organization, myofilaments expressed in fast or slow-twitch fibers and heat shock proteins localized in mitochondria or sarcoplasmic reticulum and involved in cell flux of calcium and apoptosis might be associated with differences in beef quality between Angus and Nellore. Furthermore, prohibitin appears to be a potential biomarker of intramuscular fat in cattle. Additionally, differences in phosphorylation of myofilaments and glycolytic enzymes could be involved with differences in muscle contraction force, susceptibility to calpain, apoptosis and postmortem glycolysis, which might also be related to differences in beef quality among Angus and Nellore. [ABSTRACT FROM AUTHOR]