In mammals, insulin-sensitive GLUTs, including GLUT4, are recruited to the plasma membrane of adipose and muscle tissues in response to insulin. The GLUT4 gene is absent from the chicken genome, and ...no functional insulin-sensitive GLUTs have been characterized in chicken tissues to date. A nucleotide sequence is predicted to encode a chicken GLUT12 ortholog and, interestingly, GLUT12 has been described to act as an insulin-sensitive GLUT in mammals. It encodes a 596 amino acid protein exhibiting 71% identity with human GLUT12. First, we present the results of a phylogenetic study showing the stability of this gene during evolution of vertebrates. Second, tissue distribution of chicken SLC2A12 mRNA was characterized by RT-PCR. It was predominantly expressed in skeletal muscle and heart. Protein distribution was analysed by Western blotting using an anti-human GLUT12 antibody directed against a highly conserved region (87% of identity). An immuno-reactive band of the expected size (75kDa) was detected in the same tissues. Third a physiological characterization was performed: SLC2A12 mRNA levels were significantly lowered in fed chickens subjected to insulin immuno-neutralization. Finally, recruitment of immuno-reactive GLUT12 to the muscle plasma membrane was increased following 1h of intraperitoneal insulin administration (compared to a control fasted state). Thus insulin administration elicited membrane GLUT12 recruitment. In conclusion, these results suggest that the facilitative glucose transporter protein GLUT12 could act in chicken muscle as an insulin-sensitive transporter that is qualitatively similar to GLUT4 in mammals.
This study was designed to improve the hatching performance, chick robustness and poultry health in the event of long-term egg storage and suboptimal age of the reproductive flock. A total of 9,600 ...eggs from one young breeder flock (28 weeks of age, batch B) and 9,600 eggs from an older breeder flock (59 weeks of age, batch E) were used (ROSS 308). Each batch was separated into three sub-groups and stored for 14 days. The first sub-group of eggs (Cool, group C) was stored at 11.6°C. The second sub-group of eggs (Warm, group W) was stored at 18.3°C with two pre-incubation on days 6 and 10 of the storage period. The final sub-group of eggs (Control, group Ct) was stored at 18.3°C throughout the storage period. Eggs were similarly incubated and hatched birds were raised on the same experimental farm. In both batches, embryonic development was significantly more advanced in W eggs than in C and Ct eggs (
< 0.01). In both batches, C and W treatments decreased early embryonic mortality by more than 10% compared with Ct, decreased the proportion of late-hatched chicks and improved the percentage of first grade chicks: in batch E, 42% of Ct eggs were first grade chicks vs. 57% in group W and 59% in group C. Benefits were even higher in batch B, where only 60% of Ct eggs gave first grade chicks vs. 83% in others groups. The hatching rate was thus higher in groups C and W regardless of flock age: for batch B eggs, 85% hatched in W and 84% in C vs. 62% in Ct, while for batch E eggs, 59% hatched in W and 61% in C vs. 45% in Ct. Day-old Ct chicks from batch E were heavier than W and C ones, and heavier than W chicks from batch B (
< 0.05). Long-term parameters on farm were not significantly different between groups. Thermal treatments during the storage of eggs from both young and old breeder flocks counterbalance the negative effects of prolonged egg storage on hatching rate, without altering chicken performance during rearing.
In chickens, a divergent selection on the
pHu allowed the creation of the pHu+ and pHu- lines, which represent a unique model for studying the biological control of carbohydrate storage in muscle. ...The present study aimed to describe the early mechanisms involved in the establishment of pHu+ and pHu- phenotypes. At hatching, pHu+ chicks were slightly heavier but exhibited lower plasma glucose and triglyceride and higher uric acid. After 5 days, pHu+ chicks exhibited higher breast meat yield compared to pHu- while their body weight was no different. At both ages,
muscle glycogen content was lower in pHu+ than in pHu- muscles. The lower ability of pHu+ chicks to store carbohydrate in their muscle was associated with the increased expression of
and
genes coding glucose transporters 1 and 3, and of
and
coding key enzymes of oxidative and glycolytic pathways, respectively. Reduced muscle glycogen content at hatching of the pHu+ was concomitant with higher activation by phosphorylation of S6 kinase 1/ribosomal protein S6 pathway, known to activate protein synthesis in chicken muscle. In conclusion, differences observed in muscle at slaughter age in the pHu+ and pHu- lines are already present at hatching. They are associated with several changes related to both carbohydrate and protein metabolism, which are likely to affect their ability to use eggs or exogenous nutrients for muscle growth or energy storage.
The evolution of parameters known to be relevant indicators of energy status, oxidative stress, and antioxidant defense in chickens was followed. These parameters were measured weekly from 1 to 42 ...days in plasma and/or muscles and liver of two strains differing in growth rate. At 1-day old, in plasma, slow-growing (SG) chicks were characterized by a high total antioxidant status (TAS), probably related to higher superoxide dismutase (SOD) activity and uric acid levels compared to fast-growing (FG) chicks whereas the lipid peroxidation levels were higher in the liver and muscles of SG day-old chicks. Irrespective of the genotype, the plasma glutathione reductase (GR) and peroxidase (GPx) activities and levels of hydroperoxides and α- and γ-tocopherols decreased rapidly post-hatch. In the muscles, lipid peroxidation also decreased rapidly after hatching as well as catalase, GR, and GPx activities, while the SOD activity increased. In the liver, the TAS was relatively stable the first week after hatching while the value of thio-barbituric acid reactive substances (TBARS) and GR activity increased and GPx and catalase activities decreased. Our study revealed the strain specificities regarding the antioxidant systems used to maintain their redox balance over the life course. Nevertheless, the age had a much higher impact than strain on the antioxidant ability of the chickens.
Algae represent a large and new source of nutrients with other health benefits as supplements in animal feed formulations. 'Algae' is a generic term that groups brown, green, and red types of both ...macro- and micro-algae. These marine plants may play a key role in the future for poultry production, as they constitute a new and valuable nutrient source, thanks to their nutritional composition and richness in as polyphenols, polysaccharides and fatty and amino acids. Many studies have evaluated the advantages and inconvenience of using micro- and macro-algae in poultry nutrition and their ability to improve animal health and, thus, welfare. This review describes the main nutritional characteristics of algae and the current knowledge on their effects in poultry production, impacts on animal health, growth performance and product quality (eggs and meat). The increase in laying rate and egg weight can reach +4.0 to 8.6 percentage points and +1.3 to 1.5 g, respectively. The increase in body weight of broilers and decrease in feed conversion ratio can vary from 5% to 22% and from 4% to 15%, respectively. According to the literature, a dietary incorporation rate of 2% for microalgae or a range between 1% and 5% for macroalgae is suitable for both laying hens and broiler chickens, even though these ranges greatly depend on the type of algae used and the expected benefits for poultry production.
Abstract
Glucose transport into cells is the first limiting step for the regulation of glucose homeostasis. In mammals, it is mediated by a family of facilitative glucose transporters (GLUTs) ...(encoded by SLC2A* genes), with a constitutive role (GLUT1), or insulin-sensitive transporters (GLUT4, GLUT8, and GLUT12). Compared to mammals, the chicken shows high levels of glycemia and relative insensitivity to exogenous insulin. To date, only GLUT1, GLUT8, and GLUT12 have been described in chicken skeletal muscles but not fully characterized, whereas GLUT4 was reported as lacking. The aim of the present study was to determine the changes in the expression of the SLC2A1, SLC2A8, and SLC2A12 genes, encoding GLUT1, GLUT8, and GLUT12 proteins respectively, during ontogenesis and how the respective expression of these three genes is affected by the muscle type and the nutritional or insulin status of the bird (fed, fasted, or insulin immunoneutralized). SLC2A1 was mostly expressed in the glycolytic pectoralis major (PM) muscle during embryogenesis and 5 d posthatching while SLC2A8 was mainly expressed at hatching. SLC2A12 expression increased regularly from 12 d in ovo up to 5 d posthatching. In the mixed-type sartorius muscle, the expression of SLC2A1 and SLC2A8 remained unchanged, whereas that of SLC2A12 was gradually increased during early muscle development. The expression of SLC2A1 and SLC2A8 was greater in oxidative and oxidoglycolytic muscles than in glycolytic muscles. The expression of SLC2A12 differed considerably between muscles but not necessarily in relation to muscle contractile or metabolic type. The expression of SLC2A1, SLC2A8, and SLC2A12 was reduced by fasting and insulin immunoneutralization in the PM muscle, while in the leg muscles only SLC2A12 was impaired by insulin immunoneutralization. Our findings clearly indicate differential regulation of the expression of three major GLUTs in skeletal muscles, with some type-related features. They provide new insights to improve the understanding of the fine regulation of glucose utilization in chicken muscles.
Le métabolisme glucidique de l’oiseau est important pour maitriser la croissance de l’animal et la qualité de la viande. Nous avons étudié l’utilisation périphérique du glucose chez le poulet au ...niveau musculaire en identifiant et en caractérisant les principaux acteurs impliqués. Nous avons identifié et caractérisé un nouveau transporteur de glucose chez les oiseaux, GLUT12. Il est exprimé dans les muscles, son expression est régulée in vivo par l’insuline et il peut être enrichi dans les membranes plasmiques des cellules suite à une stimulation insulinique. In vitro, une augmentation du transport de glucose est mesurée sur le même pas de temps que la translocation de GLUT12. Comme pour GLUT4 chez les mammifères, la PI3K est impliquée dans la translocation de GLUT12. L’expression des GLUTs musculaires varie avec l’âge des animaux mais aussi avec leur état physiologique, le type métabolique et/ou la fonction du muscle. L’ensemble de nos résultats explique en partie le métabolisme glucidique atypique des oiseaux et laisse entrevoir le développement de nouvelles stratégies d’élevage pour répondre à une demande croissante de produits avicoles de qualité.
Glucose metabolism in birds is important to control animal growth and meat quality. We studied peripheral glucose utilization in chicken muscle by identifying and characterizing a new glucose transporter in birds, GLUT12. This transporter is expressed in muscles, its expression is regulated in vivo by insulin and it can be enriched in cells plasma membranes following insulin stimulation. In vitro an increase of glucose transport is measured in the same time than GLUT12 translocation. As for GLUT4 in mammals, PI3K pathway is involved in GLUT12 translocation. Expression of muscular GLUTs varies depending on animals’ age but also depending on their physiological state and on the metabolic type and/or function on the muscle. All of our results partly explain the atypical glucose metabolism in birds and let us foresee development of new farming strategies in order to answer to increased demand of avian quality products.
In mammals, insulin-sensitive GLUTs, including GLUT4, are recruited to the plasma membrane of adipose and muscle tissues in response to insulin. The GLUT4 gene is absent from the chicken genome, and ...no functional insulin-sensitive GLUTs have been characterized in chicken tissues to date. A nucleotide sequence is predicted to encode a chicken GLUT12 ortholog and, interestingly, GLUT12 has been described to act as an insulin-sensitive GLUT in mammals. It encodes a 596 amino acid protein exhibiting 71% identity with human GLUT12. First, we present the results of a phylogenetic study showing the stability of this gene during evolution of vertebrates. Second, tissue distribution of chicken SLC2A12 mRNA was characterized by RT-PCR. It was predominantly expressed in skeletal muscle and heart. Protein distribution was analysed by Western blotting using an anti-human GLUT12 antibody directed against a highly conserved region (87% of identity). An immuno-reactive band of the expected size (75kDa) was detected in the same tissues. Third a physiological characterization was performed: SLC2A12 mRNA levels were significantly lowered in fed chickens subjected to insulin immuno-neutralization. Finally, recruitment of immuno-reactive GLUT12 to the muscle plasma membrane was increased following 1h of intraperitoneal insulin administration (compared to a control fasted state). Thus insulin administration elicited membrane GLUT12 recruitment. In conclusion, these results suggest that the facilitative glucose transporter protein GLUT12 could act in chicken muscle as an insulin-sensitive transporter that is qualitatively similar to GLUT4 in mammals.
Bovine embryos cultured in serum-containing media abnormally accumulate lipid droplets, compared to their in vivo counterparts. The objective of this study was to investigate the effect of different ...culture systems on the mRNA expression and on the quantification and localisation of adipocyte differentiation-related protein (ADRP), a protein associated with lipid accumulation in bovine blastocysts. Two experiments were independently performed for ADRP mRNA expression analysis. In experiment A, blastocysts were produced in modified synthetic oviduct fluid (mSOF)+10% foetal calf serum (FCS), in coculture (bovine oviduct epithelial cells, Boec) and in ewe oviducts, whereas in experiment B, they were produced in mSOF+10μM docosahexaenoic acid (DHA) and in vivo. Control groups were also performed. ADRP mRNA expression was downregulated in the Boec, ewe oviduct and in vivo groups compared to the 10% FCS or DHA groups, respectively. Moreover, the expression of this protein was downregulated in the Boec group compared to the control group (P<0.05). A third experiment (experiment C) was performed to quantify and localise ADRP protein. Boec, in vivo and control groups were tested. After immunofluorescence staining followed by confocal microscopy analysis, embryonic ADRP was clearly localised around lipid droplets, indicating that ADRP is also a lipid droplet coat protein in bovine embryos. In conclusion, our results demonstrate that bovine embryos at the blastocyst stage expressed ADRP mRNA and protein, and that the embryonic culture system modified this expression.
In mammals, insulin-sensitive GLUTs, including GLUT4, are recruited to the plasma membrane of adipose and muscle tissues in response to insulin. The GLUT4 gene is absent from the chicken genome, and ...no functional insulin-sensitive GLUTs have been characterized in chicken tissues to date. A nucleotide sequence is predicted to encode a chicken GLUT12 ortholog and, interestingly, GLUT12 has been described to act as an insulin-sensitive GLUT in mammals. It encodes a 596 amino acid protein exhibiting 71% identity with human GLUT12. First, we present the results of a phylogenetic study showing the stability of this gene during evolution of vertebrates. Second, tissue distribution of chicken SLC2A12 mRNA was characterized by RT-PCR. It was predominantly expressed in skeletal muscle and heart. Protein distribution was analysed by Western blotting using an anti-human GLUT12 antibody directed against a highly conserved region (87% of identity). An immuno-reactive band of the expected size (75kDa) was detected in the same tissues. Third a physiological characterization was performed: SLC2A12 mRNA levels were significantly lowered in fed chickens subjected to insulin immuno-neutralization. Finally, recruitment of immuno-reactive GLUT12 to the muscle plasma membrane was increased following 1h of intraperitoneal insulin administration (compared to a control fasted state). Thus insulin administration elicited membrane GLUT12 recruitment. In conclusion, these results suggest that the facilitative glucose transporter protein GLUT12 could act in chicken muscle as an insulin-sensitive transporter that is qualitatively similar to GLUT4 in mammals.
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