Hepatic lipase is an important gene in lipid metabolism, which is crucial in the growth of fish. In this study, the cDNA sequence of genetically improved farmed tilapia (GIFT) HL gene was cloned by aimed rapid amplification of cDNA ends (RACE) method. Then, the characteristics of HL were analyzed with bioinformatics methods, and the expression of HL was assessed by the quantitative real-time PCR. To study the regulation of HL expression, GIFT were fed with diets containing different contents of lipid (40, 80, and 120 g kg⁻¹) and choline (500, 750, and 1000 mg kg⁻¹) and fed with different frequencies (2 or 3 times/day) and amounts (20, 40, 60, 80, and g kg⁻¹ of body weight). Our results revealed that the GIFT HL gene has a full length of 1872 bp, encoding 493 amino acids. Consistent with the study in other species, GIFT HL was specially expressed in the liver. The HL gene of GIFT shared identity of 60.9–96.6% with other species. The expression of HL in 120 g kg⁻¹ dietary lipid and 1000 mg kg⁻¹ dietary choline group was the highest in all groups (P < 0.01). The expression of HL was increased gradually with 3 times/day frequency. All these results revealed the cDNA sequence of GIFT HL, and the expression of HL was affected by dietary choline and lipid levels, feeding frequency, and amount. This would guide the aquaculture of GIFT in the future.

肝脂肪酶是脂质代谢中的重要基因，对鱼类的生长至关重要。在这项研究中，通过有针对性的cDNA末端快速扩增（RACE）方法克隆了转基因农用罗非鱼（GIFT）HL基因的cDNA序列。然后，通过生物信息学方法分析HL的特征，并通过实时定量PCR评估HL的表达。为了研究HL表达的调节，GIFT饲喂了不同含量的脂质（40、80和120 g kg ^-1）和胆碱（500、750和1000 mg kg ^-1）的饮食，并以不同的频率（和每天2或3次）和用量（20、40、60、80和g kg ^-1体重）。我们的结果表明，GIFT HL基因的全长为1872 bp，编码493个氨基酸。与其他物种的研究一致，GIFT HL在肝脏中特别表达。GIFT的HL基因与其他物种共有60.9–96.6％的同一性。120 g kg ^-1饮食脂质和1000 mg kg ^-1饮食胆碱组中HL的表达在所有组中最高（P  <0.01）。HL的表达以3次/天的频率逐渐增加。所有这些结果揭示了GIFT HL的cDNA序列，并且HL的表达受到饮食胆碱和脂质水平，进食频率和量的影响。这将在将来指导GIFT的水产养殖。