Disparate metabolic effects of blackcurrant seed oil in rats fed a basal and obesogenic diet

Abstract

Purpose: It was hypothesised that blackcurrant seed oil beneficially modulates metabolic disorders related to obesity and its complications. The study also aimed to investigate the potentially adverse effects of an unbalanced diet on the distal intestine.

Methods: Male Wistar rats were randomly assigned to four groups of eight animals each and were fed a basal or obesogenic (high in fat and low in fibre) diet that contained either rapeseed oil (Canola) or blackcurrant seed oil. A two-way analysis of variance was then applied to assess the effects of diet and oil and the interaction between them.

Results: After 8 weeks, the obesogenic dietary regimen increased the body weight, altered the plasma lipid profile and increased the liver fat content and the plasma transaminase activities. In addition, the obesogenic diet decreased bacterial glycolytic activity and short-chain fatty acid formation in the distal intestine. Dietary blackcurrant seed oil improved the lipid metabolism by lowering liver fat accumulation and the plasma triglyceride concentration and atherogenicity as well by increasing the plasma HDL-cholesterol concentration. However, in rats fed an obesogenic diet containing blackcurrant seed oil, the plasma HDL-cholesterol concentration was comparable with both rapeseed oil-containing diets, and a significant elevation of the plasma transaminase activities was noted instead.

Conclusions: The obesogenic dietary regimen causes a number of metabolic disorders, including alterations in the hindgut microbial metabolism. Dietary blackcurrant seed oil ameliorates the lipid metabolism; however, the beneficial effect is restricted when it is provided together with the obesogenic diet, and a risk of liver injury may occur.

Fig. 1

The plasma activity of alanine transaminase (ALT) and aspartate transaminase (AST) in rats. Groups B-RO and B-BO were fed a basal diet containing rapeseed oil or blackcurrant seed oil, respectively, as the source of fat. Groups O-RO and O-SO were fed an obesogenic diet containing rapeseed oil or blackcurrant seed oil, respectively. The mean values with unlike letters of the same colour (a, b) were significantly different in Duncan’s post hoc test (P < 0.05)