Restriction of dietary protein leads to conditioned protein preference and elevated palatability of protein-containing food in rats

PHYSIOLOGY & BEHAVIOR

卷:184

Article

Murphy, Michelle¹  Peters, Kate Z.¹  Denton, Bethany S.¹  Lee, Kathryn A.¹  Chadchankar, Heramb¹  McCutcheon, James E.¹ 

[1] Univ Leicester, Dept Neurosci Psychol & Behav, Univ Rd, Leicester LE1 9HN, Leics, England

关键词: Protein;    Casein;    Carbohydrate;    Maltodextrin;    Palatability;    Microstructure;   

DOI  :  10.1016/j.physbeh.2017.12.011

来源: Elsevier

【 摘 要 】

The mechanisms by which intake of dietary protein is regulated are poorly understood despite their potential involvement in determining food choice and appetite. In particular, it is unclear whether protein deficiency results in a specific appetite for protein and whether influences on diet are immediate or develop over time. To determine the effects of protein restriction on consumption, preference, and palatability for protein we assessed patterns of intake for casein (protein) and maltodextrin (carbohydrate) solutions in adult rats. To induce a state of protein restriction, rats were maintained on a low protein diet (5% casein) and compared to control rats on non-restricted diet (20% casein). Under these dietary conditions, relative to control rats, protein-restricted rats exhibited hyperphagia without weight gain. After two weeks, on alternate conditioning days, rats were given access to either isocaloric casein or maltodextrin solutions that were saccharin -sweetened and distinctly flavored whilst consumption and licking patterns were recorded. This allowed rats to learn about the post-ingestive nutritional consequences of the two different solutions. Subsequently, during a preference test when rats had access to both solutions, we found that protein-restricted rats exhibited a preference for casein over carbohydrate whereas non-restricted rats did not. Analysis of lick microstructure revealed that this preference was associated with an increase in cluster size and number, reflective of an increase in palatability. In conclusion, protein restriction induced a conditioned preference for protein, relative to carbohydrate, and this was associated with increased palatability.

【 授权许可】

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