High carbohydrate diet ingestion increases post-meal lipid synthesis and drives respiratory exchange ratios above 1 [SHORT COMMUNICATION]

S. Talal, A. Cease, R. Farington, H. E. Medina, J. Rojas, and J. Harrison Locusts have been reported to elevate metabolic rate in response to high carbohydrate diets; this conclusion was based on metabolic rates calculated from CO2 production, a common practice for insects. However, respiratory exchange ratios (RER, CO2 production divided by O2 consumption) can rise above 1 due to de novo lipid synthesis, providing an alternate possible explanation of the prior findings. We studied the relationship between macronutrient ingestion, RER, and lipid synthesis using South American locusts (Schistocerca cancellata) reared on artificial diets varying in protein:carbohydrate (p:c) ratio. RER increased and rose above 1 as dietary p:c decreased. Lipid accumulation rates were strongly positively correlated with dietary carbohydrate content and ingestion. RERs above 1 were only observed for animals without food in the respirometry chamber, suggesting that hormonal changes after a meal may drive lipid synthesis. S. cancellata does not elevate metabolic rate on low p:c diets; in fact, the opposite trend was observed.

Source: Journal of Experimental Biology - February 3, 2021 Category: Biology Authors: Talal, S., Cease, A., Farington, R., Medina, H. E., Rojas, J., Harrison, J. Tags: SHORT COMMUNICATION Source Type: research