Effects of Various Lipid Sources and L-Carnitine Supplementation on the Growth Performance, Body Composition, and Antioxidants Enzyme Ability of Dog Conch Larvae, Laevistrombus canarium

Abstract

A feeding experiment was conducted to study the effects of dietary lipid sources and L-carnitine on the growth performance, body component, muscle fatty acid composition, and antioxidant enzyme ability of average weight of 0.28 g dog conch larvae, Laevistrombus canarium. Three sources of lipid: fish oil, soybean oil, and beef tallow were tested in combination with two levels (0 and 0.5%) of L-carnitine. The dog conch larvae fed diets containing fish oil with L-carnitine supplementation exhibited the highest weight gain. After air exposure challenge, the liver tissue of dog conch fed the diets containing soybean oil and beef tallow without supplemented L-carnitine had lower levels of superoxide dismutase (SOD, U min−1), phenoloxidase (PO, U min−1), and glutathione peroxidase (GPx, mU/mL) activity. The activity of SOD, PO, and GPx of dog conch larvae increased with increasing levels of dietary L-carnitine. In particular, dog conch larvae fed the diet containing fish oil supplemented with L-carnitine exhibited significantly ( $P<0.05$ ) enhanced antioxidant responses. The thiobarbituric acid reactive substances (TBARS) in the muscle tissue of dog conch larvae fed the diet containing fish oil without L-carnitine supplementation showed significantly ( $P<0.05$ ) higher activity. It was concluded that dietary administration of L-carnitine can enhance resistance against beta-oxidation, and the administration of fish oil in the diet was the best strategy to promote growth due to high nutritional availability.