Mitochondrial Haplogroups Influence Mitochondrial Structure and Function, Oxidative Stress, Autophagy, and Lipid Metabolism of Chicken Hepatocytes in Response to Energy Stimulation

Mitochondria are crucial carriers of maternal effects, and their function is closely related to energy metabolism and disease occurrence. Previous studies have shown that chickens with different mitochondrial haplogroups exhibit differences in production performance, but the underlying mechanism remains unclear. This study investigates the differences in mitochondrial structure and function-related indices between the A and E mitochondrial haplogroups (referred to as A-group and E-group) in recessive white-feathered chickens. It was achieved using in vivo fasting/refeeding models and an in vitro model of treating hepatocytes with nutritional factors (glucose and fatty acids). In vivo study indicated that compared to A-group chicken hepatocytes, E-group hepatocytes had shorter perimeters of mitochondria and shorter lengths of mitochondria associated with the endoplasmic reticulum membrane during refeeding (p < 0.05); mitochondria were more abundant (p = 0.05) but displayed compromised structural integrity during fasting; mitochondrial swelling was more severe during both refeeding and fasting (p < 0.01, p < 0.05); the protein level of mitofusin 2 (MFN2) was lower during fasting (p < 0.05); and there were more vacuoles and lipid accumulation in liver sections during refeeding (p < 0.05). In cultured hepatocytes, compared to A-group cells, E-group cells had higher reactive oxygen species (ROS) level after oleic acid treatments (p < 0.001); the protein level of microtubule-associated protein 1A/1B-light chain 3 beta (LC3) was lower after glucose treatment (p < 0.01), and the protein levels of MFN2 and LC3 were lower after oleic acid treatment (p < 0.01, p < 0.05). These findings suggest that mitochondrial haplogroups are associated with mitochondrial structure and function, oxidative stress, autophagy, and lipid metabolism of chicken hepatocytes in response to energy stimulation. The findings may explain how mitochondrial haplogroups affect chicken production performance.