Macronutrient selection by seven inbred mouse strains and three taste-related knockout strains

Abstract

Many animals thrive when given a choice of separate sources of macronutrients. How they do this is unknown. Here, we report some studies comparing the spontaneous choices between carbohydrate-and fat-containing food sources of seven inbred mouse strains (B6, BTBR, CBA, JF1, NZW, PWD and PWK) and three mouse models with genetic ablation of taste transduction components (T1R3, ITPR3 and CALHM1). For 8 days, each mouse could choose between sources of carbohydrate (CHO-P; sucrose-corn-starch) and fat (Fat-P; vegetable shortening) with each source also containing protein (casein). We found that the B6 and PWK strains markedly preferred the CHO-P diet to the Fat-P diet, the BTBR and JF1 strains markedly preferred the Fat-P diet to the CHO-P diet, and the CBA, NZW and PWD strains showed equal intakes of the two diets (by weight). Relative to their WT littermates, ITPR3 and CALHM1 KO mice had elevated Fat-P preferences but T1R3 KO mice did not. There were differences among strains in adaption to the diet choice and there were differences in response between males and females on some days. These results demonstrate the diverse responses to macronutrients of inbred mice and they point to the involvement of chemosensory detectors (but not sweetness) as contributors to macronutrient selection.

The BTBR mouse model of idiopathic autism – Current view on mechanisms

“…The inositol triphosphate receptor 3 gene ( Itpr3 ), was identified as responsible for the mouse tufted (tf) locus (Ellis et al 2013), which resulted with a change of the strain name from BTBR T + tf/J to BTBR T + Itpr3 tf /J. More importantly, the deletion within the Itpr3 gene was found to cause indifference of BTBR mice to sweet, Polycose, umami, bitter, and calcium tastes (Tordoff et al 2013), which in turn affects their food intake (preferential fat consumption, as compared to carbohydrate-rich diet, Tordoff et al 2014). In the light of these results, the reports of impaired social communication of food-preference in this strain (McFarlane et al 2008), as well as the use of BTBR mice to validate food reward based tasks (Martin et al 2014) need to be reconsidered.…”

Using Animal Models to Determine the Role of Gustatory Neural Input in the Control of Ingestive Behavior and the Maintenance of Body Weight

“…For example, it was reported that CALHM1 KOs were “visually indistinguishable” from their WT littermates (Vingtdeux et al 2011). However, a more detailed and longer term examinations found deficits in body mass, as well as in macronutrient intake, relative to control mice (Hellekant et al 2015; Tordoff et al 2014). Similar results have been observed with other KO models of gustatory transduction in the periphery (TRPM5 and T1R3 KOs; e.g., Damak et al 2013; Minaya 2014).…”