Evaluation of Physicochemical,Microbiological and Sensory Stability of Frozen Stored Vacuum-Packed Lamb Meat

Nowadays, lamb meat represents only 7% of all meat produced in the world. In recent years the demand for standardized lamb meat cuts has been considered of great importance and the marketing occurs predominantly in the form of frozen cuts. Herewith, the main of this work was to evaluate the stability and safety of lamb meat during frozen storage. Meats were vacuum packed in high barrier multilayer plastic iflms and stored during 12 mon at （-18±1）℃. The meat stability was assessed by physical and chemical （lipid oxidation, objective color, pH value, cooking losses and instrumental texture）, microbiological （total count of psychrotrophic, coliform count at 45℃, coagulase-positive staphylococci and the presence of Salmonella） and sensory analysis （acceptance test and visual evaluation）. The vacuum packed lamb meat remained stable as to most physical and chemical indexes. Microbiological indexes showed good stability throughout the storage period according to Brazilian legislation standards to pathogenic microorganisms. Although a signiifcant reduction in tenderness （shear force increase from 3 to 8 kg）, it showed a good sensorial acceptance for all attributes tested, including texture, with scores of around 7 （like moderately） during the 12 mon of storage. Therefore, it can be concluded that, under the conditions applied in this study, lamb meat presents a shelf life of at least 12 mon when stored at-18℃.

Effects of organic chromium supplementation to finishing lambs diet on growth performance, carcass characteristics and meat quality

The objective of this study was to evaluate supplemental organic chromium（Cr） to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs（age（4.5±0.2） mon;（25.8±3.6） kg body weight（BW）） were randomly assigned to three levels of supplemental organic Cr（0.0, 0.2 and 0.4 mg kg^–1 dry matter（DM）） in a complete random design. Growth performance was evaluated for 70 d, and then lambs were slaughtered to study carcass characteristics and chemical composition of meat. Orthogonal contrasts were performed（contrast one-average level 0.2 ppm Cr vs. average level 0.4 ppm Cr; contrast two-level 0 vs. average levels（0.2＋0.4） ppm Cr）. Orthogonal polynomials were used to estimate the linear and quadratic effects of Cr concentrations. Growth and carcass performance were not affected by supplemental organic Cr. Muscle conformation and leg perimeter linearly increased（P〈0.05） as organic Cr level increased in the diet. Kidney fat decreased linearly（P〈0.05） as supplemental Cr increased. In Longissimus dorsi（LD）, the ash content decreased linearly, and shear force（kg cm^–2） increased（P〈0.05） as organic Cr level increased in the diet. It is concluded that organic Cr did not affect growth performance, but it improved positively the muscle conformation, reduced kidney fat, whereas in LD there was an increment in shear force in finishing carcass lambs.

Cloning and Identification of Porcine HSPC117 Gene Differentially Expressed in F_(1)Crossbreds and Their Parents

To investigate the molecular basis of porcine heterosis, suppression subtractive hybridization （SSH） was performed to detect the differences in gene expression between porcine longissimus dorsi of Meishan X Large White （MS × LW） F1 hybrids and their parents Meishan pigs. An expression sequence tag （EST） differentially expressed was found, designated as ML556, which was homologous to a hypothetical protein HSPC117, from human hematopoietic stem/progenitor cells （HSPCs）, and the full-length cDNA of porcine HSPC117 was cloned using rapid amplification of cDNA ends （RACE） method. Translation of the mRNA transcript revealed an open reading frame （ORF） of 505 amino acid residues encoding a peroxisomal targeting signal （PTS） with theoretical molecular weight of 55 kDa. Alignment analysis revealed that the deduced protein sequence exhibit 98, 98, 98, 97, and 97% identity with that of cattle, human, dog, rat, and mouse, respectively. The tissue expression analysis indicated that the porcine HSPC117 gene is highly expressed in muscle, spleen, lung, kidney, uterus, ovary and testis, moderately expressed in fat, heart, and liver, and not expressed in stomach and small intestine. The possible role of porcine HSPC117 and its relationship with porcine heterosis were discussed.