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science, Canada

Urschel K.L.,University of Kentucky | Geor R.J.,Michigan State University | Shoveller A.K.,Animal and Poultry science | McCutcheon L.J.,University of Guelph | McCutcheon L.J.,Michigan State University
Equine Veterinary Journal

Reasons for performing study: Providing protein or amino acid mixtures in combination with glucose to post exercise in man has resulted in increases in the post feeding insulin response and in muscle glycogen and protein synthesis rates. However, whether protein and/or amino acids can modify the post exercise insulin responses in horses remains to be fully elucidated.Objectives: To determine whether whey protein or leucine addition to a glucose solution affects the post gavage plasma insulin, glucose and amino acid responses in horses and whether these responses are different following a period of exercise vs. rest. Methods: Six mature, conditioned Thoroughbreds received a nasogastric gavage containing either 1 g/kg bwt glucose (G), G + 0.3 g/kg bwt whey protein (GW) or G + 0.3 g/kg bwt leucine (GL), following a period of either rest (R) or an exercise test on a high speed treadmill (EX). Each horse was studied under all 6 treatment conditions, separated by 10 day intervals. Blood samples were collected pre-exercise/rest, pregavage and at regular intervals up to 300 min post gavage. Plasma was analysed for glucose and amino acid concentrations and serum insulin concentrations were determined. Results: There was a significantly (P<0.05) greater insulin response in GL-R and GL-EX when compared to the other treatments. When compared to rest, post exercise plasma glucose responses were lower in G and GW but unchanged following GL administration. Plasma alanine concentrations were elevated post exercise in all EX treatments. With the exception of markedly elevated plasma leucine concentrations after GL-R and GL-EX, the plasma concentrations of all indispensable amino acids decreased during the post gavage period.Conclusions: Leucine but not whey protein augmented the serum insulin response to an oral glucose load. Leucine supplementation warrants further investigation as a means to increase the rate of post exercise muscle glycogen synthesis in horses. © 2010 EVJ Ltd. Source

Zhang W.,Animal and Poultry science | Bai S.,Animal and Poultry science | Liu D.,Human Nutrition | Cline M.A.,Animal and Poultry science | Gilbert E.R.,Animal and Poultry science
Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology

Neuropeptide Y is an evolutionarily conserved neurotransmitter that stimulates food intake in higher vertebrate species and promotes adipogenesis in mammals. The objective of this study was to determine if NPY also enhances adipogenesis in birds, using chickens as a model. The stromal-vascular fraction of cells was isolated from the abdominal fat of 14. day-old broiler chicks and effects of exogenous chicken NPY on proliferation and differentiation determined. Based on a thymidine analog incorporation assay and gene expression analysis, there was no effect of NPY on proliferation during the first 12. hours post-treatment in cells that were induced to proliferate. However, there were effects of NPY treatment on proliferation and lipid accumulation during the first 6. days post-induction of differentiation. Neuropeptide Y supplementation during induction of differentiation was associated with greater glycerol-3-phosphate dehydrogenase activity and staining for neutral lipids, indicative of augmented lipid accumulation. This was also accompanied by increased proliferation during differentiation, which was characterized by up-regulation of proliferation and preadipocyte marker mRNA, and a greater number of proliferating cells in groups that were treated with NPY. Additionally, NPY treatment was associated with increased expression of fatty acid binding protein 4 and lipoprotein lipase during differentiation. In conclusion, these results suggest that NPY plays a role in promoting adipogenesis in chickens and that the mechanisms involve an increase in the synthesis of new preadipocytes and increased lipid synthesis and storage. © 2014 Elsevier Inc. Source

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