Effect of biological additives on Japanese eel (Anguilla japonica) growth performance, digestive enzymes activity and immunology. Issue 84 (January 2019)

• Record Type: Journal Article
• Authors: Zheng, Cheng-cai; Cai, Xin-yi; Huang, Meng-meng; Mkingule, Idefonce; Sun, Cong; Qian, Shi-Chao; Wu, Zhen-ju; Han, Bing-nan; Fei, Hui
• Is Part Of: Fish & shellfish immunology. Issue 84(2019)
• Page Start: 704
• Page End: 710
• Publication Date: 2019-01
• Subjects: Bacillus amyloliquefaciens -- Yarrowia lipolytica lipase 2 -- Anguilla japonica -- Growth performance -- Digestive enzymes activity -- Resistance to pathogens -- Innate immunity; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2018.10.048
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: Japanese eel ( Anguilla japonica ) has become a commercially important fish species all over the world. High-density aquaculture has led to congestion and contributed to bacterial infection outbreaks that have caused high mortality. Therefore a 56-days feeding trial was conducted to determine the effects of dietary Bacillus amyloliquefaciens (GB-9) and Yarrowia lipolytica lipase2 (YLL2) on growth performance, digestive enzymes activity, innate immunity and resistance to pathogens of A. japonica . Fish growth performance was significantly affected by dietary YLL2 supplementation but not by GB-9. Fish fed diets with YLL2 at 2.0 g/kg diet in combination of high and low levels of GB-9 (5.0 g/kg and 2.0 g/kg) produced the highest growth. For digestive enzyme, lipase and trypsin activities was promoted by dietary containing YLL2, while amylase activities was increased by dietary containing YLL2, GB-9 single or combination. For innate immunity, the mucus lysozyme activity, leukocytes phagocytosis activity and reactive oxygen species level of skin, peroxidase and lysozyme activity of serum were enhanced in fish fed with GB-9 compared to those in control group (p < 0.05). The highest resistance to Vibrio anguillarum and Aeromonas hydrophila was determined in fish fed with 5.0 g kg −1 GB-9 + 2.0 g/kg YLL2. This study demonstrated that GB-9 and YLL2 enhanced non-specific immune defense system of A. japonica, providing them with higher resistance to pathogens. The present results suggested that the combination of these supplements could be considered as potential biological additives for aquaculture farmed fish. Highlights: The supplementations of YLL2 resulted in a significant increase in growth performance of Japanese eel. The lysozyme and peroxidase activity, phagocytosis rates, ROS level were significantly higher in supplemented group. The digestive enzymes activity were significantly higher in GB-9 supplemented group. The survival rate of Japanese eel challenged with V. anguillarum and A. hydrophila was significantly improved.