Skip to Main content Skip to Navigation
Journal articles

The protein status of rats affects the rewarding value of meals due to their protein content

Abstract : Background: Protein status is controlled by the brain, which modulates feeding behavior to prevent protein deficiency. Objective: This study tested in rats whether protein status modulates feeding behavior through brain reward pathways. Methods: Experiments were conducted in male Wistar rats (mean ± SD weight; 230 ± 16 g). In experiment 1, rats adapted for 2 wk to a low-protein (LP; 6% of energy) or a normal-protein (NP; 14% of energy) diet were offered a choice between 3 cups containing high-protein (HP; 50% of energy), NP, or LP feed; their intake was measured for 24 h. In 2 other experiments, the rats were adapted for 2 wk to NP and either HP or LP diets and received, after overnight feed deprivation, a calibrated HP, NP, or LP meal daily. After the meal, on the last day, rats were killed and body composition and blood protein, triglycerides, gut neuropeptides, and hormones were determined. In the brain, neuropeptide mRNAs in the hypothalamus and c-Fos protein and opioid and dopaminergic receptor mRNAs in the nucleus accumbens (NAcc) were measured. Results: Rats fed an LP compared with an NP diet had 7% lower body weight, significantly higher protein intake in a choice experiment (mean ± SD: 30.5% ± 0.05% compared with 20.5% ± 0.05% of energy), higher feed-deprived blood ghrelin, lower postmeal blood leptin, and higher neuropeptide Y (Npy) and corticotropin-releasing hormone (Crh) mRNA expression in the hypothalamus. In contrast to NP, rats fed an LP diet showed postmeal c-Fos protein expression in the NAcc, which was significantly different between meals, with LP < NP < HP. In contrast, in rats adapted to an HP diet compared with an NP diet, energy intake was lower; and in the NAcc, meal-induced c-Fos protein expression was 20% lower, and mRNA expression was 17% higher for dopamine receptor 2 (Drd2) receptors and 38% lower for κ opioid receptor (Oprk1) receptors. Conclusion: A protein-restricted diet induced a reward system–driven appetite for protein, whereas a protein-rich diet reduced the meal-induced activation of reward pathways and lowered energy intake in male rats.
Document type :
Journal articles
Complete list of metadata

https://hal.inrae.fr/hal-02623717
Contributor : Migration Prodinra <>
Submitted on : Tuesday, May 26, 2020 - 9:09:23 AM
Last modification on : Tuesday, June 15, 2021 - 2:56:54 PM

Links full text

Identifiers

Collections

Citation

Catherine Chaumontet, Isidra Recio, Gilles Fromentin, Simon Benoit, Julien Piedcoq, et al.. The protein status of rats affects the rewarding value of meals due to their protein content. Journal of Nutrition, American Society for Nutrition, 2018, 148 (6), pp.989-998. ⟨10.1093/jn/nxy060⟩. ⟨hal-02623717⟩

Share

Metrics

Record views

33