Intestinal fatty acid binding protein gene (I-FABP) in golden pompano Trachinotus ovatus (Linnaeus 1758) larvae: ontogenetic expression and response to water temperature and nutrition manipulation

Abstract

The gene for fatty acid binding proteins (I-FABP) in golden pompano Trachinotus ovatus larvae was cloned and analyzed from hatch to 18 dayspost hatch (DPH). The I-FABP gene (GenBank accession: MF034871) of golden pompano is composed of 815 bp with an open reading frame of 399 bp, encoded in one amino acid with a molecular weight of 15.24 kDa. The predicted amino acid sequence of I-FABP genes from golden pompano showed high similarity and identity with Japanese sea bass Lateolabrax japonicus (97% and 87.9%, AOW69620.1). The highest tissue expression of I-FABP genes was found in the intestine, followed by the eye on 18 DPH. During the ontogenetic development, the expression of I-FABP genes remained at a low level during the first five days, and reached the highest level on 12 and 18 DPH. The expression of I-FABP genes was not significantly affected by environmental temperature on 12 DPH, but was significantly affected by the temperature on 18 DPH. Nutrition enhancement with algae containing high fatty acids significantly affected the expression of I-FABP genes. The highest expression was observed in the non-enriched treatment, but the lowest expression was in the Nannochloropsis feeding treatment. Results of the present study indicate that the expression of the I-FABP gene varies with environmental temperature and nutritional conditions during the ontogenetic development of golden pompano larvae. The expression of I-FABP genes may be potentially used as an indicator for assessing nutrient supply and functional development of the digestive system in fish larvae. The IJA appears exclusively as a peer-reviewed on-line open-access journal at http://www.siamb.org.il/. To read papers free of charge, please register online at registration form. Sale of IJA papers is strictly forbidden. 137 amino acids depending on species (Chen and Shi, 2009; Pelsers et al., 2005; Sharma et al., 2004). FABPs can mediate the transportation of free fatty acids for targeting specific metabolic pathways, protecting cells from cytotoxic effects of free fatty acids, modifying lipid metabolic enzymes, and participating in fatty acid signaling within the nucleus (Besnard et al., 2002; Lowe et al., 1987; Storch and McDermott, 2009). Different FABP types have been named after the mammalian tissue from which they were first isolated, such as intestine, heart, liver, myelin, and adipose tissues. Early studies have confirmed that the existence of these FABP types fulfilled specific roles associated with the histological structure and physiological functions of different tissues (Banaszak et al., 1994; Veerkamp et al., 1991; Veerkamp et al., 1993). The intestinal fatty acid-binding protein (I-FABP) is a small cytosolic protein and has been considered to play a crucial role in intracellular fatty acid trafficking and metabolism in fish gut (Her et al., 2004). Evidence has indicated that the expression of I-FABP genes is an important marker for intestinal differentiation in humans (Sonnino et al., 2000), rats (Likic and Prendergast, 1999), frogs (Chalmer...