Effects of dietary lipid levels on the expression of CPT1 in Micropterus salmoides

To study the effect of lipid level on the expression of carnitine palmitoyl transferase I (CPT1) gene in the body tissues of Micropterus salmoides and the expression patterns of different growth stages, three different isonitrogenous diets with graded levels of lipid 6% (low lipid), 12% (medium lipid) and 18% (high lipid) were fed to M. salmoides with the initial weight of (23.60 ± 1.26) g. Tissue samples of liver, intestine, kidney and muscle were taken on the 30th, 60th and 90th day of feeding, and the 18S was used as the internal reference gene. The real-time PCR experiment was performed with CPT1 specific primers, and the relative expression data of CPT1 gene were obtained by 2^−△△C_T method. The results showed that the expression level of CPT1 gene was the highest in the liver, followed by intestine and kidney, and the expression level was lower in gill filament, heart, muscle, stomach, brain and spleen; at different fat levels, the expression of CPT1 increased with the increase of lipid level; in different growth stages, the expression of CPT1 increased with the prolongation of feeding time. The results showed that the increase of lipid level and feeding time would induce the expression of CPT1 gene, and CPT1 gene may play a certain role in the decomposition of fat in M. salmoides.