Programming of the glucose metabolism in rainbow trout juveniles after chronic hypoxia at hatching stage combined with a high dietary carbohydrate: Protein ratios intake at first-feeding

It is well known that change in environmental parameters experienced during early life can have profound effect on the metabolism of individuals later in life. The purpose of the present study was to evaluate the impact of a chronic hypoxic stimulus (15 days, 50% dissolved O2, 5.0 mg·L−1) applied at hatching (oxygen history) alone or combined with a 60% high carbohydrate (HC) dietary stimulus (8 days) applied at first-feeding (dietary history) on growth performance and glucose metabolism of juvenile trout. The effectiveness of the hypoxic and the HC dietary stimuli were verified by monitoring the modulation in mRNA levels of oxygen-sensitive and dietary carbohydrate-sensitive genes, respectively. At juvenile stage (28 weeks after first-feeding), neither dietary history nor oxygen history had long-term effect on growth performance. These juveniles were then subjected to a 5 days challenge test with a 30% carbohydrate diet. Our data showed that mRNA levels of some glucose transport-related genes in liver and muscle, and plasma triglycerides were down-regulated in fish which were exposed to hypoxia during early life. Regarding to the effect of dietary history, the mRNA level of muscular pfkmaa was observably increased in fish previously subjected to the HC dietary stimulus. In summary, the present study indicated that a chronic hypoxic stimulus applied at hatching alone or combined with a high carbohydrate stimulus at first-feeding can affect plasma triglycerides level and glucose metabolism-related genes in juvenile trout.