Effects of dietary Lactobacillus plantarum and AHL lactonase on the control of Aeromonas hydrophila infection in tilapia.
This study addressed the effects of dietary Lactobacillus plantarum or/and N-acylated homoserine lactonase (AHL lactonase) on controlling Aeromonas  hydrophila infection in juvenile hybrid tilapia (Oreochromis niloticus♀ × O. aureus ♂). Fish were fed Lb. plantarum subsp. plantarum strain JCM1149 (10(8)  CFU/g feed) or/and AHL lactonase AIO6 (4 U/g) and were exposed to a chronic challenge of A. hydrophila NJ-1 (10(5)  cells/mL) for 14 days. Intestinal (foregut) alkaline phosphatase (IAP) activities were evaluated 1 day post challenge to reflect the resistance of fish against A. hydrophila infection. Parallel groups of fish with the same dietary assignments while unchallenged were also included to investigate the effect of dietary Lb. plantarum or/and AIO6 supplementation on gut health of tilapia. The results showed that IAP activity was significantly lower in fish fed with diets supplemented with Lb. plantarum JCM1149 or the combination of Lb. plantarum JCM1149 and AIO6, indicating enhanced resistance against A. hydrophila. Light microscopy and transmission electron microscopy images of foregut revealed damage caused by A. hydrophila NJ-1, but dietary Lb. plantarumJCM1149 or/and AIO6 significantly alleviated the damages. Compared to the fish immersed in A. hydrophila NJ-1, dietary Lb. plantarum JCM1149 or AIO6 could maintain the microvilli length in the foregut of tilapia. However, among the unchallenged groups of fish, the microvilli length in the foregut of tilapia fed AIO6 (singly or combination) and the microvilli density of tilapia fed AIO6 (singly) were significantly lower than those of the control, though the microvilli density in the combination treatment was significantly improved. Additionally, the dietary Lb. plantarum JCM1149 could down-regulate the expression of stress-related gene in the gut after the acute phase. In conclusion, the dietary Lb. plantarum JCM1149 is recommended to control the A. hydrophila infection in tilapia.
Key Laboratory of Freshwater Biodiversity Conservation and Utilization, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.|Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.|Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science, Nanchang, Jiangxi, 330200, China.
Wenshu
W
Liu
Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Chao
C
Ran
Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Zhi
Z
Liu
College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
Qian
Q
Gao
Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Shude
S
Xu
Faculty of Biosciences, Fisheries and Economics, Norwegian College of Fishery Science, UiT The Arctic University of Norway, Tromsø, Norway.
Einar
E
Ringø
Institute of Anatomy and Cell Biology, University of Bergen, Bergen, Norway.
Reidar
R
Myklebust
Key Laboratory of Freshwater Biodiversity Conservation and Utilization, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Zemao
Z
Gu
Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Zhigang
Z
Zhou
D016980:Aeromonas hydrophila / Q000187:drug effects / Q000472:pathogenicity*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000821:Animal Feed / Q000382:microbiology; D000818:Animals; D017756:Aquaculture / Q000379:methods; D002265:Carboxylic Ester Hydrolases / Q000494:pharmacology*; D004032:Diet; D005393:Fish Diseases / Q000382:microbiology / Q000628:therapy*; D048191:Lactiplantibacillus plantarum / Q000378:metabolism*; D019936:Probiotics / Q000494:pharmacology*; D017210:Tilapia / Q000382:microbiology*
D002265:Carboxylic Ester Hydrolases; C432003:N-acyl homoserine lactonase; D000469:Alkaline Phosphatase
AHL lactonase; disease; immunity; lactobacillus; tilapia