RESUMO
The present study was carried out to evaluate dietary Mn requirements of broilers from 22 to 42 d of age using molecular biomarkers. Chickens were fed a conventional basal maize-soyabean meal diet supplemented with Mn as Mn sulphate in graded concentrations of 20 mg Mn/kg from 0 to 140 mg Mn/kg of diet for 21 d (from 22 to 42 d of age). The Mn response curves were fitted for ten parameters including heart Mn-containing superoxide dismutase (MnSOD) mRNA and its protein expression levels and the DNA-binding activities of specificity protein 1 (Sp1) and activating protein-2 (AP-2). Heart MnSOD mRNA and protein expression levels showed significant quadratic responses (P<0·01), and heart MnSOD activity showed a broken-line response (P<0·01), whereas Mn content and DNA-binding activities of Sp1 and AP-2 in the heart displayed linear responses (P<0·01) to dietary Mn concentrations, respectively. The estimates of dietary Mn requirements were 101, 104 and 94 mg/kg for full expressions of MnSOD mRNA level, MnSOD protein level and MnSOD activity in the heart, respectively. Our findings indicate that heart MnSOD mRNA expression level is a more reliable indicator than heart MnSOD protein expression level and its activity for the evaluation of Mn requirement of broilers, and about 100 mg Mn/kg of diet is required for the full expression of heart MnSOD in broilers fed the conventional basal maize-soyabean meal diet from 22 to 42 d of age.
Assuntos
Proteínas Aviárias/metabolismo , Galinhas/fisiologia , Regulação Enzimológica da Expressão Gênica , Manganês/administração & dosagem , Miocárdio/metabolismo , Necessidades Nutricionais , Superóxido Dismutase/metabolismo , Animais , Proteínas Aviárias/química , Proteínas Aviárias/genética , Biomarcadores/metabolismo , Galinhas/crescimento & desenvolvimento , China , Ingestão de Energia , Coração/crescimento & desenvolvimento , Masculino , Manganês/análise , Manganês/metabolismo , Compostos de Manganês/administração & dosagem , Miocárdio/enzimologia , RNA Mensageiro/metabolismo , Distribuição Aleatória , Reprodutibilidade dos Testes , Fator de Transcrição Sp1/química , Fator de Transcrição Sp1/metabolismo , Sulfatos/administração & dosagem , Superóxido Dismutase/química , Superóxido Dismutase/genética , Fator de Transcrição AP-2/química , Fator de Transcrição AP-2/metabolismo , Aumento de PesoRESUMO
Tea plant (Camellia sinensis) is an important natural resource for the global supply of non-alcoholic beverage production. The extension of tea plant cultivation is challenged by biotic and abiotic stresses. Transcription factors (TFs) of the APETALA 2 (AP2)/ethylene-responsive factor (ERF) family are involved in growth and anti-stresses through multifaceted transcriptional regulation in plants. This study comprehensively analyzed AP2/ERF family TFs from C. sinensis on the basis of the transcriptome sequencing data of four tea plant cultivars, namely, 'Yunnanshilixiang', 'Chawansanhao', 'Ruchengmaoyecha', and 'Anjibaicha'. A total of 89 putative AP2/ERF transcription factors with full-length AP2 domain were identified from C. sinensis and classified into five subfamilies, namely, AP2, dehydration-responsive-element-binding (DREB), ERF, related to ABI3/VP (RAV), and Soloist. All identified CsAP2/ERF genes presented relatively stable expression levels in the four tea plant cultivars. Many groups also showed cultivar specificity. Five CsAP2/ERF genes from each AP2/ERF subfamily (DREB, ERF, AP2, and RAV) were related to temperature stresses; these results indicated that AP2/ERF TFs may play important roles in abnormal temperature stress response in C. sinensis.