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The effect of fasting on the appetite-associated factors and energy sensors expression in the hypothalamus of different TI broilers
Tonic immobility (TI) is a behaviour related to fear and stress response. Bird can exhibit a short (STI) or long (LTI) tonic immobility phenotype on the basis in TI duration. In this study, the differences in the hypothalamic appetite-associated factors and energy sensor gene expression between STI and LTI broilers were evaluated under free feed access or 16 h fasting. The results showed that the concentrations of cholesterol (CHOL), high density lipoprotein-cholesterol (HDL-C), non-esterified fatty acid (NEFA), malonaldehyde (MDA), lactate dehydrogenase (LDH), creatine kinase (CK), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma were significantly increased (P < 0.05) in fasting broilers compared to broilers fed ad libitum, while plasma glucose (Glu), triglyceride (TG), and total antioxidant capacity (TAOC) concentrations were decreased (P < 0.05). With respect to TI, however, only low density lipoprotein-cholesterol (LDL-C) and glutathione peroxidase (GSH-Px) concentrations in plasma showed significant differences between LTI and STI broilers, with higher concentrations in LTI compared to STI. Real-time PCR results showed that only NPY mRNA expression demonstrated a tendency to increase in STI broilers compared to LTI (P = 0.095). Fasting down-regulated SREBP-1 and its target gene FAS but up-regulated CPT1 in the hypothalamus. Additionally, levels of hypothalamic p-GR and p-AMPK protein expression decreased after fasting. These results indicate that a 16 h fasting results in a negative energy status, and is accompanied with changes in expression of hypothalamic energy sensor and appetite-associated factors.
AN15473 Accepted 31 July 2017
© CSIRO 2017