Effects of dietary energy level on the transcription of the H-FABP gene in different tissues of sheep

Abstract

A total of 36 four-month-old crossbred lambs (Dorset × Thin-tailed Han sheep) with similar BW were randomly allocated to three dietary treatments with different energy (7.21, 10.33 and 13.49 MJ d⁻¹ ME). Longissimus dorsi, femoral biceps and cardiac muscle tissue were sampled and total RNA was extracted to determine relative transcript levels of the Heart-type fatty acid-binding proteins (H-FABP) gene by real-time PCR. The results showed that the abundance of H-FABP mRNA in different tissues of sheep increased with the elevation of dietary energy. In the longissimus dorsi and femoral biceps muscles, the H-FABP mRNA levels showed significant differences among the three groups (P < 0.01); in the cardiac muscle, the H-FABP mRNA level in the high energy group was significantly higher than that in the moderate and low energy groups (P < 0.01), and the H-FABP mRNA level in the moderate energy group was significantly different from the low energy groups (P < 0.05). The number of H-FABP copies (Qty) in different tissues of sheep was different, it was greater in the cardiac muscle tissue than in longissimus dorsi muscle and femoral biceps muscle.

Introduction

Heart-type fatty acid-binding proteins (H-FABP) are thought to facilitate both cellular uptake and intracellular transport of fatty acids and contribute to efficient fat storage and utilization. Intracellular transport of fatty acids towards sites of metabolic conversion is most likely accomplished by cytoplasmic fatty acid-binding proteins (Schaap et al., 1998). Calvo et al. (2002) cloned and sequenced H-FABP gene of sheep. Qiao et al. (2009) studied the polymorphisms of H-FABP gene and five nucleotide variations were found in different sheep breeds. Many studies showed that H-FABP gene was an important candidate gene for meat quality and correlated with intramuscular fat (IMF) contents in pigs and chickens (Uemoto et al., 2007, Wang et al., 2007, Cho et al., 2009, Li et al., 2010), and there was significant difference in mRNA expression level of H-FABP gene in different tissues (Veerkamp and van Moerkerk, 1993, Gardan et al., 2007, Tu et al., 2010). In this study, we compared the differences in relative transcript levels of the H-FABP gene among muscular and cardiac tissues in sheep fed with different dietary energy levels. The objective was to clarify the differences in relative transcript levels of the H-FABP gene in the different tissues under different dietary energy levels, and to provide a theoretical basis for the further study of the function of the H-FABP gene in the muscles of sheep.