Affiliation:
1. Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea (Ministry of Agriculture and Rural Affairs), Dalian Ocean University, Dalian 116023, China
2. Hubei Key Laboratory of Yeast Function, Angel Yeast Co., Ltd., Yichang 443000, China
3. Angel Yeast Co., Ltd., Yichang 443000, China
Abstract
This study was performed to investigate the effects of selenium yeast (Se-yeast) on the growth, intestinal health, immune status and body composition of juvenile Apostichopus japonicus before and after aestivation. Five experimental diets were formulated with increasing addition of Se-yeast (0, 0.5, 1.0, 1.5 and 2.0 mg/kg), with the diet without Se-yeast as the control. Each diet was randomly assigned to three tanks of juvenile A. japonicus (initial body weight: 2.96 ± 0.04 g). The whole experiment lasted for 135 days, which included a 45-day feeding experiment before aestivation, a 60-day aestivation phage and a 30-day feeding experiment after aestivation. The results showed that weight gain rate (WGR) was significantly increased by the increasing addition of Se-yeast before aestivation. After aestivation, WGR was markedly elevated by 1.0 mg/kg Se-yeast but was inhibited by 1.5–2.0 mg/kg Se-yeast. The evisceration rate (ER) of A. japonicus was obviously inhibited by the relatively higher addition level of Se-yeast (1.5–2.0 mg/kg) before aestivation. After aestivation, the ER was significantly inhibited by Se-yeast at an addition of 1.5 mg/kg. Before aestivation, the highest activities of all digestive enzymes were obtained by Se-yeast addition at a level equal to or above 1.0 mg/kg Se-yeast. After aestivation, the activities of most digestive enzymes were maximized by Se-yeast at the addition level of no more than 1.0 mg/kg. Before aestivation, the activities of nitric oxide synthase and alkaline phosphatase significantly increased by the increasing addition of Se-yeast. After aestivation, immune related parameters exhibited the highest or comparable values when the addition level of Se-yeast was equal to or less than 1.0 mg/kg. Notably, the selenium content in the body wall of A. japonicus increased significantly as Se-yeast addition increased in the diets. These results showed that Se-yeast at the addition level of 1.5–2.0 mg/kg before aestivation and 1.0–1.5 mg/kg after aestivation was beneficial for the promotion of growth, intestinal health and immune status of juvenile A. japonicus.
Funder
High-Level Talent Support Grant for Innovation in Dalian
Subject
Ocean Engineering,Water Science and Technology,Civil and Structural Engineering