Effect of dietary fatty acids on lipoprotein lipase gene expression in the liver and visceral adipose tissue of fed and starved red sea bream Pagrus major

Juvenile red sea bream Pagrus major were fed either a commercial diet (diet 1) or diets supplemented with 10% oleate (diet 2), 5% oleate+5% linoleate (diet 3) or 5% oleate+5% n-3 polyunsaturated fatty acid mixture (diet 4) for 4 weeks. Following the conditioning period, the effects of dietary fatty acids on lipoprotein lipase (LPL) gene expression in the liver and visceral adipose tissue of fed (5 h post-feeding) and starved (48 h post-feeding) fish were investigated by competitive polymerase chain reaction. Fish liver showed substantial LPL mRNA expression that is not found in adult rat liver. When compared with diet 1, diets 2-4 tended to increase the LPL mRNA level in the liver, but tended to decrease it in the visceral adipose tissue under the fed condition. The reciprocal regulation of the liver and visceral adipose LPL mRNA abundance by dietary fatty acids was comparable to that of rat brown and white adipose tissue, respectively. The change in the LPL mRNA level by fatty acids was not completely consistent with the degree of fatty acid unsaturation. Our results indicate that the regulatory effect of dietary fatty acids on LPL gene expression was tissue-specific and related to feeding conditions, but was not solely dependent on the degree of unsaturation of fatty acids.