Osteocalcin prevents insulin resistance, hepatic inflammation, and activates autophagy associated with high-fat diet–induced fatty liver hemorrhagic syndrome in aged laying hens

• Published in: Poultry science 2021-01, Vol.100 (1), p.73-83
• Main Authors: Wu, X.L., Zou, X.Y., Zhang, M., Hu, H.Q., Wei, X.L., Jin, M.L., Cheng, H.W., Jiang, S.
• Format: Article
• Language: English
• Subjects: Animals; Autophagy - drug effects; Chickens; Diet, High-Fat; Fatty Liver - prevention & control; Fatty Liver - veterinary; fatty liver hemorrhagic syndrome; Female; hen; high-fat diet; Immunology, Health and Disease; Inflammation - prevention & control; Inflammation - veterinary; Insulin Resistance; Liver - drug effects; metabolic disorder; osteocalcin; Osteocalcin - pharmacology; Poultry Diseases - etiology; Poultry Diseases - pathology; Poultry Diseases - prevention & control; Random Allocation
• ISSN: 0032-5791; 1525-3171
• DOI: 10.1016/j.psj.2020.10.022

The aim of this study was to investigate the effects of osteocalcin (OCN) on fatty liver hemorrhagic syndrome (FLHS) in aged laying hens. Thirty 68-week-old White Plymouth laying hens were randomly assigned into conventional single-bird cages, and the cages were randomly allocated into one of 3 treatments (n = 10): normal diet (ND + vehicle, ND + V), high-fat diet (HFD + vehicle, HFD + V), and HFD + OCN (3 μg/bird, 1 time/2 d, i.m.) for 40 d. At day 30, oral glucose tolerance tests (OGTT) and insulin tolerance tests (ITT) were performed. At the end of experiment, the hens were euthanized followed by blood collection. The plasma aspartate transaminase (AST), alkaline phosphatase (ALP), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured using an automatic biochemistry analyzer. Pathological changes in the liver were examined under both light and transmission electron microscopes. The plasma inflammatory factors including interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-α) were analyzed by ELISA, and the gene expressions of these inflammatory factors in the liver were analyzed by real-time PCR. The level of oxidative stress was evaluated using malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) assay kits, respectively. The results showed that HFD + V hens had more severe liver hemorrhage and fibrosis than ND + V hens (P