TWO DIETARY BETAINE SUPPLEMENTATIONS ON GROWTH, FEED UTILIZATION, LIPID METABOLISM, AND IMMUNE RESPONSE OF WHITE SHRIMP (LITOPENAEUS VANNAMEI) FED TWO LEVELS OF COMPOUND ATTRACTANTS

Feed attractants have been widely used to improve the palatability of aquatic animal feeds, but there are few studies on the effects of feed attractants on growth and health of Litopenaeus vannamei. This study aims to investigate the effects of betaine supplementations on growth performance, feed utilization, lipid metabolism, and immune response of Litopenaeus vannamei fed two levels of raw feed attractants (8%, 0). Juvenile shrimp initial body weight (0.71±0.00) g were randomly distributed into four groups, each group included four fiberglass tanks 30 shrimp in each tank (0.3 m³). The shrimp were fed with raw feed attractants group (P), soybean meal replacing feed attractants in P (N), raw feed attractants + betaine group (PB) and betaine supplementation group (NB) for 7 weeks, respectively. Results showed that the raw feed attractants enhanced the expression levels offas, acc, sod, dorsal, relish in hepatopancreas, as well as toll and sod in the intestine of shrimp, while the expression levels of relish in the intestine were reversed. Betaine increased ash content in muscle, upregulated fas,acc, sod, and dorsal in hepatopancreas, as well as sod expression in the intestine, while it decreased feed intake, muscle crude lipid, low density lipoprotein cholesterol, malondialdehyde contents and total nitric oxide synthase activity in hepatopancreas, as well as the expression levels of acox, cpt-1,myd88 and relish in hepatopancreas. The interaction of raw feed attractants and betaine had significant effects on feed conversion ratio, hepatopancreas total nitric oxide synthase activity, ampk, acc, cpt-1, sod, myd88 and relish. In conclusion, a diet with 1.30% yeast extract +4.80% squid viscera powder+1.90% fish soluble improves the immunity and antioxidant capacity of shrimp. Dietary 0.6% betaine reduces feed intake and promotes lipid utilization, and up-regulates the expression of immune-related genes of shrimp. This study showed that two dietary betaine supplementations on growth, feed utilization, lipid metabolism, and immune response of white shrimp (Litopenaeus vannamei) fed two levels of compound attractants, which provides reference value for white shrimp culture.