Open AccessDietary supplementation with Bacillus subtilis LT3‐1 enhance the growth, immunity and disease resistance against Streptococcus agalactiae infection in genetically improved farmed tilapia, Oreochromis niloticus
Author(s) -
Zhu Chuanzhong,
Yu Lijuan,
Liu Wei,
Jiang Ming,
He Shan,
Yi Ganfeng,
Wen Hua,
Liang Xufang
Publication year - 2019
Publication title -
aquaculture nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 79
eISSN - 1365-2095
pISSN - 1353-5773
DOI - 10.1111/anu.12938
Subject(s) - biology , oreochromis , streptococcus agalactiae , tilapia , bacillus subtilis , lysozyme , streptococcus iniae , microbiology and biotechnology , feed conversion ratio , food science , immune system , zoology , streptococcus , immunology , bacteria , endocrinology , biochemistry , fishery , body weight , fish <actinopterygii> , genetics
A feeding trial was conducted to investigate the effect of different levels of Bacillus subtilis LT3‐1 in diets on growth, immune parameters, intestinal morphology and disease resistance in genetically improved farmed tilapia, Oreochromis niloticus . Fish (46.91 ± 0.17 g) were fed with a basal diet supplemented with B. subtilis LT3‐1 at 0 (B0), 3.8 × 10 10 (B1), 7.6 × 10 10 (B2), 1.14 × 10 11 (B3) and 1.52 × 10 11 (B4) CFU kg −1 for 6 weeks. The results showed that the weight gain of fish in B1 group was significantly enhanced compared to that in B0 group ( p < 0.05). The addition of B. subtilis significantly affected serum biochemical indices (total protein, albumin, aspartate aminotransferase, alkaline phosphatase). Besides, the haematocrit, total counts of red and white blood cells, as well as the serum catalase and lysozyme activities, were increased, whereas the serum malondialdehyde, the serum immunoglobulin M and complement three contents were reduced. Parameters for intestinal morphology suggested a healthier intestine for the fish fed B. subtilis ‐supplemented diets than fish fed the control diet. The survival rate after Streptococcus agalactiae challenge increased in tilapia fed with B. subtilis . The present study demonstrated B. subtilis can effectively improve growth, immunological status and resistance against S. agalactiae infection in tilapia farming.