Triglyceride measurements

TG levels were analyzed by the TG quantitation kit (ab65336, abcam; Waltham, MA, USA) from the abalone intestine according to the manufacturer’s protocol. Briefly, lipids were extracted by homogenizing 100 mg of intestine tissues in 1 mL of 5% NP-40 solution using a pestle and mortar and then slowly heated to 95°C in the water bath for 5 min. The samples were cooled, heated to solubilize all TGs into solution, and centrifuged at 15,200 g force for 2 min at room temperature. The supernatant was diluted 10 times with double-distilled water, and lipase and TG reaction mixture were added as the kit supplier recommended. The mixed samples were incubated at room temperature for 1 h while protected from light, and the absorbance was analyzed on a microplate reader (EL800, Bioteck, Vermont (VT), USA) at 562 nm.