Estudo da expressão génica de enzimas reguladoras do metabolismo intermediário em ovinos sujeitos a restrição alimentar

• Author(s): Brito, Renata Alves Paiva de
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.5/4086
• Origin: Repositório da UTL
• Subject(s): lambs; food restriction; intermediary metabolism; gene expression; real-time PCR
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Cardoso, Luís Granger Alfaro; Mourato, Miguel Barbosa
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia

The effect of food restriction on expression of genes encoding the regulatory enzymes of intermediary metabolism was studied. We used two distinct breeds of lambs (Australian Merino and Dorper) which were submitted to two nutritional treatments: food restriction (80% of daily requirements for maintenance) and control (ad libitum feeding) during 42 days. The animals were divided into four experimental groups (Australian Merino Control, Australian Merino Restriction, Dorper Control and Dorper Restriction). After the trial, the animals were slaughtered and samples were collected from liver tissue, which were used to quantify the expression of genes encoding the synthesis of relevant intermediary metabolism enzymes (Hexokinase, Fosfofructokinase, Pyruvate kinase, Pyruvate carboxylase, Phosphoenolpyruvate carboxykinase, Fructose 1,6-bisphosphatase, Glucose-6-phosphatase, Glycogen phosphorylase, Glycogen synthase, Acetyl CoenzymeA carboxylase, Fatty acid synthase, Hepatic lipase, Glutamate dehydrogenase e Carbamoyl phosphate synthase), through Real Time PCR. The results showed a superiority of Dorper sheep in maintaining glucose homeostasis. Food restriction led to a significant decrease of gene expression of glycolytic enzymes in Dorper animals. The expression of gluconeogenic enzymes showed no changes in experimental animals and the lipogenic enzymes showed an equal decrease of expression in two experimental breeds. The Dorper breed also showed a reduced use of aminoacids and an increase in the synthesis of urea. These results are consistent with the reductions found in body weight (15,3% for the Australian Merino and 7,5% for Dorper), which reflect a better nutritional performance of the Dorper breed.