In order to understand the structure and function of heart type fatty acid binding protein H-FABP,the full-length cDNA sequence of H-FABP gene was cloned from obscure puffer(Takifugu obscurus)by using SMART RACE technique.The entire H-FABP cDNA was 772 bp,containing a 402 bp open reading frame encoding a protein with 133 amino acids.Bioinformatics analysis indicated that the H-FABP gene had a conserved domain of lipocalin family and several phosphorylation sites.Phylogenetic analysis indicated that the H-FABP gene of Takifugu obscurus was closely related to Takifugu rubripes,followed by that of Perciformes.Real-time PCR revealed that H-FABP gene was ubiquitously expressed in all tested tissues.The highest expression of H-FABP was tested in the liver,followed by muscle and heart.This indicates that H-FABP is mainly involved in fatty acid oxidation process.To evaluate the feasibility of using soybean oil as a dietary lipid,juvenile fish were fed with four formulated diets differing in lipid composition,with soybean oil accounting for 0,25%,50% and 75% of total dietary lipid respectively.After feeding for 8 weeks,the expression of H-FABP gene in the liver of the fish oil group was significantly higher than those in 50% soybean oil group and 75% soybean oil group(P<0.05).However,there was no significant difference(P >0.05)between the 25% soybean oil group and the fish oil group.The expression of H-FABP gene in the liver decreased with the increasing of the proportion of soybean oil in diets,indicating that fish oil rich in n-3 polyunsaturated fatty acids can promote fatty acid oxidation and prevent fatty liver.Therefore,in order not to affect the liver fat metabolism of obscure puffer,the proportion of soybean oil instead of fish oil should be less than 50%.