Differential effects of propionate or β‐hydroxybutyrate on genes related to energy balance and insulin sensitivity in bovine white adipose tissue explants from a subcutaneous and a visceral depot1

Abstract

Ruminants rely on short-chain fatty acids (SCFA) as principal energy source. Herein, we compared the effects of propionate, β-hydroxybutyrate (BHB) and insulin on mRNA abundance of energy balance-related genes by short-term incubation (4 h) in bovine subcutaneous (SC) and retroperitoneal (RP) adipose tissue (AT) explants in vitro. Propionate either significantly (p < 0.05), or as a trend (p ≤ 0.1) affected mRNA abundance of genes such as adiponectin system in both depots in treated samples versus controls. Propionate increased adiponectin receptor 1 (AdipoR1) and AdipoR2 mRNA only in SC AT. β-hydroxybutyrate decreased mRNA abundance of adiponectin and AdipoR1 in SC AT as a trend. The mRNA abundance of free fatty acid receptor 2/3 (FFAR2/3) and other genes of interest (GOI) was increased during differentiation in bovine preadipocyte culture. The mRNA abundance of all the GOI remained unchanged after short-term insulin stimulation. In total, propionate, BHB or insulin during short-term treatment exert divergent effects on the mRNA abundance of GOI in both depots in vitro. Our results indicate that the bovine adiponectin system might be more sensitive to propionate than to BHB. We demonstrated the presence of FFAR2/3 mRNA not only in both AT depots but also in differentiating preadipocytes isolated from bovine SC AT. Therefore, we established that SCFA are able to exert insulin-independent effects on bovine adipose tissue, which might be independent from propionate uptake-related events.