Nutrient Sensing and Modulations of Protein Utilization in Fish
Gen He*1,2, Xuan Wang1, Haowen Jiang1, Kangsen Mai1, 2
1. Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
2. Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
Increase efficiency of protein utilization in fish is critical in aquaculture. We have been studying the signaling network that senses the nutritional status and modulates the nitrogen metabolism in several fish species. We have demonstrated that the postprandial amino acid influx and duration vary among different protein sources in turbot. More importantly, such variation leads to distinct activation of nutrient sensing pathways and anabolism/catabolism. Thus, our study provides a promising model on the phenotypic performances of different protein sources. Furthermore, we showed that methionine deficiency (MD) was detected and translated into highly integrated transcriptional, proteomic, and metabolic responses. Initially, inhibition of target of rapamycin (TOR) and activation of amino acid response (AAR) signaling by MD led to reduced protein synthesis. Then, MD triggered degradation of multiple amino acids, highlighting the tight regulation of amino acid balance in cells. Reduced glycolysis and lipogenesis, as well as increased lipolysis by MD demonstrated the close metabolic connections among macronutrients. Increased catabolism and energy expenditure under MD clearly demonstrated that cellular homeostasis was maintained by intricate and inter-connected signaling and metabolic pathways. Limitation of a single nutrient, such as methionine, would likely be sensed and trigger cascades of signaling and metabolic consequences and disrupt homeostasis. Our results clearly suggest that differential nutrient sensing responses are critical for the nutrient utilization in fish.
Acknowledgements: Supported by: NSFC to GH, and 973 program grant to KM.
Key Words: nutrient sensing, aquaculture, protein sources, utilization, metabolism
Gen He*1,2, Xuan Wang1, Haowen Jiang1, Kangsen Mai1, 2
1. Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
2. Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
Increase efficiency of protein utilization in fish is critical in aquaculture. We have been studying the signaling network that senses the nutritional status and modulates the nitrogen metabolism in several fish species. We have demonstrated that the postprandial amino acid influx and duration vary among different protein sources in turbot. More importantly, such variation leads to distinct activation of nutrient sensing pathways and anabolism/catabolism. Thus, our study provides a promising model on the phenotypic performances of different protein sources. Furthermore, we showed that methionine deficiency (MD) was detected and translated into highly integrated transcriptional, proteomic, and metabolic responses. Initially, inhibition of target of rapamycin (TOR) and activation of amino acid response (AAR) signaling by MD led to reduced protein synthesis. Then, MD triggered degradation of multiple amino acids, highlighting the tight regulation of amino acid balance in cells. Reduced glycolysis and lipogenesis, as well as increased lipolysis by MD demonstrated the close metabolic connections among macronutrients. Increased catabolism and energy expenditure under MD clearly demonstrated that cellular homeostasis was maintained by intricate and inter-connected signaling and metabolic pathways. Limitation of a single nutrient, such as methionine, would likely be sensed and trigger cascades of signaling and metabolic consequences and disrupt homeostasis. Our results clearly suggest that differential nutrient sensing responses are critical for the nutrient utilization in fish.
Acknowledgements: Supported by: NSFC to GH, and 973 program grant to KM.
Key Words: nutrient sensing, aquaculture, protein sources, utilization, metabolism