Gene expression of regulatory enzymes involved in the intermediate metabolism of sheep subjected to feed restriction
S. van Harten,
R. Brito,
A.M. Almeida,
T. Scanlon,
T. Kilminster,
J. Milton,
J. Greeff,
C. Oldham,
L.A. Cardoso
Affiliations
S. van Harten
Instituto de Investigação Científica Tropical, Centro de Veterinária e Zootecnia, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal; Centro Interdisciplinar de Investigação em Sanidade Animal, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal
R. Brito
Instituto de Investigação Científica Tropical, Centro de Veterinária e Zootecnia, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal; Centro Interdisciplinar de Investigação em Sanidade Animal, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal
A.M. Almeida
Instituto de Investigação Científica Tropical, Centro de Veterinária e Zootecnia, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal; Centro Interdisciplinar de Investigação em Sanidade Animal, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal
T. Scanlon
Department of Agriculture and Food Western Australia, 3 Baron-Hay Court, South Perth, 6151 Western Australia, Australia
T. Kilminster
Department of Agriculture and Food Western Australia, 3 Baron-Hay Court, South Perth, 6151 Western Australia, Australia
J. Milton
Faculty of Natural and Agricultural Sciences, UWA Institute of Agriculture M082, University of Western Australia, Crawley 6009, Western Australia, Australia
J. Greeff
Department of Agriculture and Food Western Australia, 3 Baron-Hay Court, South Perth, 6151 Western Australia, Australia
C. Oldham
Department of Agriculture and Food Western Australia, 3 Baron-Hay Court, South Perth, 6151 Western Australia, Australia
L.A. Cardoso
Instituto de Investigação Científica Tropical, Centro de Veterinária e Zootecnia, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal; Centro Interdisciplinar de Investigação em Sanidade Animal, Faculdade de Medicina Veterinária, Av. da Universidade Técnica, Pólo Universitário da Ajuda, 1300-477 Lisboa, Portugal
The effect of feed restriction on gene expression of regulatory enzymes of intermediary metabolism was studied in two sheep breeds (Australian Merino and Dorper) subjected to two nutritional treatments: feed restriction (85% of daily maintenance requirements) and control (ad libitum feeding), during 42 days. The experimental animals (ram lambs) were divided into four groups, n = 5 (Australian Merino control (MC), Australian Merino Restriction (MR), Dorper control (DC) and Dorper Restriction (DR)). After the trial, animals were sacrificed and samples were taken from liver tissue to quantify glucose levels and gene expression of relevant intermediary metabolism enzymes (phosphofructokinase (PFK), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, glucose-6-phosphatase, glycogen synthase (GS), fatty acid synthase (FAS), glutamate dehydrogenase (GDH) and carbamoyl phosphate synthase (CPS)) through real-time PCR. During the experimental period, the MR animals lost 12.6% in BW compared with 5.3% lost by the Dorper lambs. MC and DC rams gained, respectively, 8.8% and 14% during the same period. Within the Dorper breed, restricted feed animals revealed a significant decrease over controls in the transcription of PFK (1.95-fold) and PK (2.26-fold), both glycolytic enzymes. The gluconeogenesis showed no change in the feed restricted animals of both breeds. DR feed group presented a significant decrease over the homologous Merino sheep group on GS. In both experimental breeds, FAS mRNA expression was decreased in restricted feed groups. GDH expression was decreased only in the DR animals (1.84-fold) indicating a reduced catabolism of amino acids in these animals. Finally, CPS was significantly (P < 0.05) higher in the Dorper sheep, indicating a facilitated urea synthesis in this breed. These results indicate a better adaptation of metabolic intermediate regulatory enzymes and hepatic glucose production of Dorper sheep to feed restriction concurring with the BW results in the experimental groups.
