The growth performance, anti-oxidative capacity, immunity and resistance to heat stress of abalone Haliotis discus hannai can be improved by a mixture of herbs

Abstract

An 84-day feeding trial was carried out to assess the effects of dietary Chinese herbs mixture (CHM) on the growth performance, anti-oxidative capacity, immunity and resistance to heat stress of abalone Haliotis discus hannai. The CHM included, Scutellariae Radix (Scutellaria baicalensis, Gardeniae Fructus (Gardenia jasminoides), Artemisiae Scopariae Herba (Artemisia capillaris), Uncariae Ramulus Cum Uncis (Uncaria rhynchophylla), Polygoni Cuspidati Rhizoma et Radix (Polygonum cuspidatum). Six diets containing 0.00% (control group), 0.02%, 0.04%, 0.06%, 0.08% and 0.10% of CHM were formulated and fed to abalone (initial weight: 3.59 ± 0.03 g). The group with 0.04% of dietary CHM exhibited the highest weight gain rate (WGR), while the survival was not significantly affected by dietary CHM. The optimal level of dietary CHM for abalone was determined to be 0.049% on the basis of the quadratic regression model for WGR. Dietary CHM significantly elevated the activities of lipase, trypsin, cellulase, Na+/K+-ATPase, acid phosphatase, alkaline phosphatase and lysozyme and total anti-oxidative capacity. Besides, dietary CHM significantly reduced the malondialdehyde content and alanine amino transferase activity. The mRNA levels of cationic amino acid transporter 1 (cat1) and nuclear factor erythroid 2-related factor 2 (nrf2) were significantly up-regulated in the group with 0.04% of dietary CHM. While the mRNA levels of kelch-like ECH-associated protein 1 (keap1), nuclear factor-κb (nf-κb) and tumor necrosis factor-α (tnf-α) were decreased in dietary CHM supplemented groups. The glucose and cortisol content in the CFH and the falling rate of abalone were significantly lower in the CHM supplemented groups than that in the control group. In conclusion, dietary supplementation of CHM improved the growth performance, anti-oxidative capacity, immunity and the resistance to heat stress of abalone. The recommended level of CHM supplemented in diets for abalone was 0.049%.