Hervé Rémignon

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: Pépoi, 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 neighbour‐joining 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

In 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.

Current advances in proteomic analysis of (fatty) liver.

In this review, an overview on proteomic studies conducted in livers of farm animals is conducted with a special focus on liver steatosis in waterfowl. Several studies had interest in understanding liver metabolism in dairy cows under various conditions (e.g. fasting) or the evolution of liver proteome during embryonic phases or growing periods in chicken. Those studies provide interesting results leading to a better understanding of the liver metabolism. Liver steatosis development in waterfowl represents a special case and a focus on proteomic studies conducted in these birds will be done. Indeed, recent studies aimed at resolving protein evolution during overfeeding in duck. Proteomic analysis combining two complementary approaches (2-dimensional electrophoresis gels and shot gun strategy) in order to better understand the mechanisms underlying the variability of cooking yield of fatty liver will be presented.

Are one early muscle pH and one early temperature measurement sufficient to detect PSE breast meat in turkeys

1. Within a large flock of turkey toms (2000 BUT9 conventionally reared and slaughtered), early muscle pH measurements were randomly done to distinguish two groups of birds presenting low (fast glycolysing, GR) or normal (normal glycolysing, GN) values. 2. Subsequently, ultimate pH values and meat quality parameters were also recorded. Meat quality parameters from GR or GN samples differ more or less indicating more or less severe PSE conditions. Proteins extracted from the samples at 20 min post mortem were similar while they differed greatly at 24 h post mortem. Moreover, among the GR birds, a subgroup of animals (called AB) presented SDS-PAGE profiles largely different from other GR or GN birds. 3. All the subsequent analysis developed on meat quality parameters as well as for protein extractabilities also differed between AB and other animals indicating that they must be considered differently in term of PSE syndrome development. 4. Western blots against Myosin Heavy Chain and actin at 24 h post mortem indicate that myofibrillar protein alterations are different in AB and GR or GN samples. 5. At 20 min post mortem, glycogen content was lowest in AB samples while the glycolytic potential was similar in all samples at the time of death. Measurements of PFK enzyme specific activity did not indicate a different regulation of post mortem glycolysis in AB samples. 6. Our results suggest that a unique pH measurement at 20 min post is insufficient to detect animals more prone to developing a severe PSE syndrome in turkeys. In consequence, it is suggested that a more precise evaluation of the kinetics of pH and temperature decrease has to be conducted to understand the aetiology of meat quality parameter alterations in poultry.

Effects of Physical Activities on Biochemical and Biomechanical Properties of Tendons in Two Commercial Types of Chickens

The aim of our experiment was to study the effects of physical activities on the biochemical and biomechanical properties of tendons in 12 standard (S) broilers and 12 Label Rouge (LR) chickens. In the two types of birds no differences were found between control and active birds for body weights. Gastrocnemius (Gas) tendon and Pectoralis minor (Pm) tendons were harvested and processed for passive stretch tests prior to cooking or not. Some biochemical parameters also were determined. Results showed that total collagen content in Gas tendon was significantly higher in active than in control birds. However, no significant changes were found in collagen solubility in LR tendons while these values were increased in S ones. Active birds showed greater sGAGs content than control ones. Ultimate load was found to be significantly higher in active birds than in control. Deformability (defined by Poissons ratio) of raw and heated at 80°C Gas tendons increases in active groups because Poissons ratio decreases. Physical activities also increase the rigidity (defined by elastic modulus) of raw and heated at 80°C Gas tendons because elastic modulos values increase. Physical activity was not able to modify stiffness or maximum stress values in raw or heated at 80°C Gas tendons from broilers whereas these two parameters were found to be slightly higher in active group from LR chickens only in raw tendons. All the biomechanical results recorded in Pm tendons from both types of chickens were not significantly different between control and active birds. A significant correlation was found between the total collagen content and stiffness in Gas tendon from LR active birds.

Achieving sustainable production of poultry meat, volume 3, health and welfare

This volume is divided into two parts consisting of 16 chapters written by several international scientists. It is part of a series of three books dedicated to sustainable production of poultry meat. This volume reports recent knowledge relating to poultry health (part 1) and welfare (part 2). All chapters are more or less illustrated with tables and figures reporting recent scientific results but there is always a large citation of updated literature related to the concerned topic. Moreover, at the end of each chapter, a section entitled ‘Where to look for further information’ indicates books, reports or websites where the interested reader can find further information. In the first part of the book, related to poultry health, readers are given very general information on disease prevention and management in poultry flocks. Specific focuses are made on gut health and leg disorders because these specific pathologies can dramatically affect poultry performance at a subclinical level. Two other chapters give general information on the most common viruses and parasites that can be encountered in poultry flocks but, amazingly, none deals with bacterial infections (apart from the ones concerning gut health and leg disorders) such as colibacillosis, pasteurellosis, tuberculosis and salmonellosis. Complementary chapters of this first part of the book are more targeted towards disease management in poultry flocks with a special emphasis on ways to boost poultry immune systems and how to use competitive exclusion treatments to control pathogens in poultry. These chapters are the most targeted towards a more sustainable production because they describe new trends to decrease the massive use of antibiotics in poultry. However, it is a pity that very few illustrated results, showing bird performance obtained with probiotics for example, are presented. Part two of the book deals with an overview of poultry behaviour and welfare. Besides generalities, interesting specific focuses concern key methodological challenges for behavioural studies and case studies on welfare of broilers in an enriched environment, in free range or hot weather conditions, during transportation or at slaughtering. Those cases are interesting because they clearly address one of the three pillars (social acceptability) of the sustainable production of broilers. At this point, readers must be informed that this volume is restricted to poultry meat production and consequently no information concerning the welfare or behaviour of laying hens is given. More surprisingly, a whole chapter is dedicated to the effect of incubation temperature on embryonic development in poultry. It is well done and written but the reader can only wonder about its presence in a book dedicated to the sustainability of poultry meat production As a whole, this book presents two very distinct parts with no real links between them and a very tenuous one with sustainability. Nevertheless, all scientific presentations are of a very good quality and students or general readers will find there good information about health and welfare of broilers.

Two-Dimensional Zymography of Proteases from Steatotic Duck Liver

Protease activity present in liver cells with steatosis can be electrophoretically characterized. Zymographic techniques allow semi-quantitative results, successfully detecting cathepsin and metalloprotease activity using polyacrylamide gels copolymerized with gelatin and quantified by densitometry. By using specific inhibitors, the identity of the proteases can be confirmed. 2D zymography allows the determination of both M r. and pI of the metalloprotease and cathepsin activity present in the homogenates. The analysis of liver proteases activities in force fed ducks may elucidate the mechanisms behind steatosis development.