This study aims to establish a model that will allow the comparison of the phenotypic variations between a fat-preferring strain and a macronutrient non-preferring strain of mouse.Methods
Five strains (AKR, A/J, ARC, C57Bl/6 and BALB/c) were fed a two-choice diet (high-fat/low-carbohydrate and low-fat/high-carbohydrate) for 30 days. Following completion of the 30-day feeding period, the brains of the fat-preferring and macronutrient non-preferring mice were removed for the analysis of the expression of the genes – agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC).Results
Upon completion of the experiment, it was found that the C57Bl/6 strain was the strongest fat preferrer consuming 72% of their calories from the high-fat diet, whereas the BALB/c was found to have no macronutrient preference. Using in situ hybridization techniques, no significant differences in the expression of POMC were found between the two strains. It was, however, showed that the BALB/c mice had a 33.7% higher expression level of AgRP than the C57Bl/6 mice.Conclusions
The lower expression level of AgRP in the C57Bl/6 mice may be suggestive of a defensive response to their chronic preferential consumption of the high-fat diet. However, the wide variety of neuroregulatory signals involved in macronutrient preference along with the possibility of the occurrence of post-transcriptional effects suggests further biological analyses need to be performed using this model.