Effect of concananavalin A from jackbean seeds on short-term food intake regulation in chicks and laying hens

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Comparaison de l'aptitude des pepsines de porc et de poulet à hydrolyser les protéines

International audienceThe aim of the present study was to compare the degree of proteolysis with pig (PP) and chicken (CP) pepsins in order to find out whether PP can be used instead of CP to simulate gastric hydrolysis in the chicken. First, the pH activity profile of the two pepsins was compared using three substrates. For haemoglobin, CP showed a slightly higher optimal pH than PP, 2.5-3 and 2, respectively. For two plant protein sources (peas, wheat), the optimal pH was similar for the two enzymes, about pH 1.5. For the three substrates tested, CP exhibited a high level of activity over a broader pH range than PP. Second, the susceptibility of the two plant proteins to hydrolysis by each of the two pepsins was studied at pH levels near the chicken gastric pH (1.5-3.5). For PP, pea proteins were hydrolysed more than wheat ones, while, for CP, the hydrolysis was dependent on pH. Therefore, the classification of the two studied protein sources was dependent on the enzyme species and pH. The results of this study show that the choice of in vitro hydrolysis conditions to assess the digestibility of proteins must be made with great car

Lipogenesis gene expression in divergently selected lean and fat chickens

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Apoprotein A1 mRNA levels differ in genetically lean and fat chickens.

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Apoprotein A1 mRNA levels differ in genetically lean and fat chickens.

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Protein metabolism in heat-exposed chickens

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L'engraissement chez le poulet : aspects métaboliques et génétiques

Chantier qualité spécifique "Auteurs Externes" département de Génétique animale : uniquement liaison auteur au référentiel HR-AccessNational audienceIncrease in adipose tissues in meat-chicken carcasses has prompted investigations in order to control this unfavourable trait, to the benefit of both producers and consumers. Comparisons between experimental lean and fat chicken strains have pointed out the main metabolic differences between lean and fat birds. The main results are recalled. In addition, recent results regarding hepatic enzyme activities and mRNA amounts involved in various metabolic steps (amino acid catabolism, lipogenesis per se, lipid maturation and secretion) are reported. Many of these measurements are higher in fat chickens compared than in lean ones. A hypothesis of a common regulation of these different metabolic steps, explaining most of the differences, is proposed. Each step could, however, be individually responsible for fatness variability as it seems to occur for the glutamate desydrogenase enzyme.L’augmentation du poids de tissus adipeux présents dans les carcasses de poulet de chair a incité à en rechercher les causes, afin de pouvoir maîtriser ce caractère défavorable, tant pour les producteurs que pour les consommateurs. La comparaison de lignées expérimentales génétiquement grasses et maigres a permis d’identifier les différences métaboliques majeures entre animaux gras et maigres. Elles sont rappelées dans cet article. Les résultats les plus récents concernant le métabolisme hépatique, analysé à différentes étapes (catabolisme des acides aminés, lipogenèse proprement dite, maturation et sécrétion des lipides) par des mesures d’activités enzymatiques ou de quantités d’ARN messagers, sont rapportés. Ils montrent que beaucoup de ces paramètres sont plus élevés chez les animaux gras comparés aux maigres. L’hypothèse d’une régulation commune pour ces différentes étapes du métabolisme est avancée. Cependant, chaque étape peut aussi être individuellement responsable des différences d’engraissement, comme cela semble être le cas pour l’enzyme glutamate déshydrogénase