Aim: 

The present study aimed to evaluate the effect of different dietary fat sources (lard or fish oil) on: i) obesity, hyperlipidemia, insulin resistance and liver steatosis development, ii) liver mitochondrial energy efficiency.

Methods: 

Three groups of rats were fed, for 6 weeks, three different diets: standard diet (N rats), high fat diet rich in lard (40% J/J, L rats), or in fish oil (40% J/J, F rats).

Body energy balance, serum triglycerides levels and oral glucose tolerance were analysed. Liver steatosis and glycogen content were assessed in haematoxylin-eosin stained sections and PAS (Periodic acid-Schiff reactive) method respectively. Hepatic mitochondrial energy efficiency was determined by measuring proton leak kinetics.

Results: 

L rats showed increased body weight and lipid gain, triglyceride serum levels, insulin response to oral glucose load, total body and hepatic mitochondrial energy efficiency compared to N rats. All these parameters were lowered in F rats compared to L ones. F and L rats liver showed diffusely mixed steatosis, which was predominantly microvescicular in F rats while L rats showed increased LDs vescicular size. L rats showed the widest glycogen depleted areas in liver PAS section.

Conclusions: 

High fat diet rich in fish oil, compared to high fat diet rich in lard, reduced obesity, insulin resistance and hepatic steatosis development by decreasing total body and mitochondrial energy efficiency.

Conflict of Interest: 

None disclosed

Funding: 

No funding