Exposure of 7-week-old normal rats for 3-7 months to a diet deprived of long-chain polyunsaturated omega3
fatty acids was recently reported to induce changes in the
fatty acid content and pattern of liver
phospholipids and
triglycerides similar to those otherwise found in second generation omega3-depleted rats. In the present study, the changes in
body weight, parametrial adipose tissue mass, plasma
glucose and
insulin concentrations and
insulin resistance index were investigated in the same control and omega3-depleted rats, which were then given access for 2 to 4-5 weeks to either a
flaxseed oil-enriched diet (control and omega3-depleted rats) or a
soybean oil-enriched diet (control rats). The
body weight failed to differ between control and omega3-depleted rats. The latter rats, however, displayed increases in adipose tissue mass, plasma
glucose and
insulin concentrations, and
insulin resistance index. In the control rats given access to the soybean or
flaxseed oil-enriched diet,
body weight and adipose tissue mass were little affected, but both the plasma
glucose concentration and
insulin resistance index decreased. In the omega3-depleted rats given access to the
flaxseed oil-enriched diet, both
body weight and adipose tissue mass underwent a rapid, pronounced and sustained increase, whilst the plasma
glucose concentration and
insulin resistance index decreased similarly to those in the control rats. The present design of omega3
fatty acid dietary deprivation thus reproduces the
visceral obesity and
insulin resistance otherwise observed in second-generation omega3-depleted rats. However, the supply of exogenous omega3
fatty acids to the omega3-depleted rats failed to oppose
visceral obesity, possibly as a result of the orexigenic effects of these omega3
fatty acids.