Abstract
Effects of dietary firefly squid on serum and liver lipid levels were investigated. Male Wistar rats were fed a diet containing 5% freeze-dried firefly squid or Japanese flying squid for 2 weeks. There was no significant difference in the liver triacylglycerol level between the control and Japanese flying squid groups, but the rats fed the firefly squid diet had a significantly lower liver triacylglycerol content than those fed the control diet. No significant difference was observed in serum triacylglycerol levels between the control and firefly squid groups. The rats fed the firefly squid had a significantly lower activity of liver glucose-6-phosphate dehydrogenase compared to the rats fed the control diet. There was no significant difference in liver fatty acid synthetase activity among the three groups. Hepatic gene expression and lipogenic enzyme activity were investigated; a DNA microarray showed that the significantly enriched gene ontology category of down-regulated genes in the firefly squid group was “lipid metabolic process”. The firefly squid group had lower mRNA level of glucose-6-phosphate dehydrogenase compared to the controls. These results suggest that an intake of firefly squid decreases hepatic triacylglycerol in rats, and the reduction of mRNA level and enzyme activity of glucose-6-phosphate dehydrogenase might be related to the mechanisms.
