Using 2-DE for the differentiation of local chicken breeds

The aim of this study was to apply a proteomic approach for the characterisation of local chicken breeds. The experiment involved a total of 29 males of three local Italian chicken breeds: Pe\ub4poi, Padovana and Ermellinata di Rovigo. Sarcoplasmic protein fractions of breast muscle were analysed by 2-DE. Image analysis followed by statistical analysis enabled to differentiate groups of individuals based on the similarities of protein expression. Individuals were distinguished into clusters and groups, corresponding to the breed of origin. Distances among individuals, calculated using data on spot volumes, were used to draw a neighbourjoining tree, showing clear individual and breed grouping. The most relevant spots regarding breed differentiation were detected; 11 were identified by MS revealing preliminary evidences on the mechanisms of the breed differentiation process. The results evidenced the ability of proteomic analyses for the characterisation of chicken breeds

Functional genomics of the muscle response to restraint and transport in chickens

International audienceIn the present study, we used global approaches (proteomics, transcriptomics, and metabolomics) to assess the molecular basis of the muscle response to stress in chickens. A restraint test, combined with transport for 2 h (RT test) was chosen as the potentially stressful situation. Chickens (6 wk old) were either nontreated (control chickens) or submitted to the RT test (treated chickens). The RT test induced a 6-fold increase in corticosterone concentrations, suggesting hypothalamic-pituitary-adrenal axis activation. The RT test decreased the relative abundance of several hexose phosphates [glucose-1-P (G1P), glucose-6-P (G6P), fructose-6-P (F6P), and mannose-6-P (M6P)] in thigh muscle. In addition, 55 transcripts, among which 39 corresponded to unique annotated genes, were significantly up- (12 genes) or downregulated (27 genes) by treatment. Similarly, 45 proteic spots, among which 29 corresponded to unique annotated proteins, were overexpressed (11 proteins), underexpressed (14 proteins), or only expressed in treated chickens. Integrative analysis of differentially expressed genes and proteins showed that most transcripts and proteins belong to 2 networks whose genes were mainly related with cytoskeleton structure or carbohydrate metabolism. Whereas the decrease in energetic metabolites suggested an activation of glycogenolysis and glycolysis in response to the RT test, the reduced expression of genes and proteins involved in these pathways suggested the opposite. We hypothesized that the prolonged RT test resulted in a repression of glycogenolysis and glycolysis in thigh muscle of chickens. The down-expression of genes and proteins involved in the formation of fiber stress after the RT test suggests a reinforcement of myofibrils in response to stress

Modeling the relationships between quality and biochemical composition of fatty liver in mule ducks

The fatty liver of mule ducks, i.e. French 'foie gras', is the most valuable product in duck production systems. Its quality is measured by the technological yield, which is the opposite of the fat loss during cooking. The purpose of this study was to determine whether biochemical measures of fatty liver could be used to accurately predict the technological yield (TY). Ninety one male mule ducks were bred, overfed and slaughtered under commercial conditions. Fatty liver weight (FLW) and biochemical variables, such as dry matter content (DM) and lipid (LIP) and protein content (PROT) were collected. To evaluate evidence for nonlinear fat loss during cooking, we compared regression models describing linear and nonlinear relations between biochemical measures and TY. We detected significantly greater than linear relation between DM and TY. Our results indicate that LIP and PROT follow a different pattern (linear) than DM and showed that LIP and PROT are nonexclusive contributing factor to TY. Other components such as carbohydrates other than those measured in this study could contribute to DM. Stepwise regression for TY was performed. The traditional model with the FLW was tested. The results showed that the weight of the liver is of limited value in the determination of fat loss during cooking (R2 = 0.14). The most accurate TY prediction equation included DM (in linear and quadratic terms), FLW and PROT (R2 = 0.43). Biochemical measures in the fatty liver were more accurate predictors of TY than liver weight. The model is useful in commercial conditions because DM, PROT an FLW are non invasive measures