title: Isolation of a putative probiotic strain S12 and its effect on growth performance, non-specific immunity and disease-resistance of white shrimp, Litopenaeus vannamei.
abstract: The common pathogens in aquaculture are very different from those in terrestrial animals. The objective of this study was to isolate probiotic strain (s) from the digestive tract of healthy white shrimp Litopenaeus vannamei which was effective against aquatic animal pathogens. The putative probiotic strain S12 was identified as Bacillus subtilis based on the morphological and biochemical properties and 16S rDNA gene sequencing. The L. vannamei were fed with five different diets: control (basal diet with no probiotics or antibiotics), antibiotic control (basal diet supplemented with 0.3% florfenicol), basal diet supplemented with 5 × 10(9) cfu kg(-1) , 5 × 10(10) cfu kg(-1) and 5 × 10(11) cfu kg(-1) probiotic S12 (PS1-3). Each diet was randomly fed to quadruplication groups of 40 shrimps (0.4 ± 0.01 g) reared in tanks. After an 8-week feeding, the survival rate of shrimps fed with PS1 and PS3 were the highest among all treatments (P < 0.05). The moisture content of shrimps fed with florfenicol was significantly lower than that of the control group (P < 0.05). The supplement of probiotic S12 decreased the body crude lipid significantly (P < 0.05). The activities of phagocytic rate, lysozyme (LZ), superoxide dismutase phenoloxidase (SOD) and antibacterial activity were significantly higher than those in the control (P < 0.05), and the activities of SOD and the antibacterial activity in PS2 and PS3 were significantly higher than those in antibiotic control (P < 0.05). When infected with Vibrio harveyi at 4-weeks, the mortality was significantly lower (P < 0.05) in PS2 and PS3 groups than that in the control. After being infected with V. harveyi at 8-weeks, the mortality was significantly lower in the probiotic and antibiotic groups than that in the control (P < 0.05). This study suggested that probiotics could be used as an effective immunopotentiator, the optimal dose of the probiotic strain S12 is 5 × 10(10) cfu kg(-1) diet.
authors.affiliation: Laboratory of Aquatic Animal Nutrition and Feed, Fisheries College, Guangdong Ocean University, Zhanjiang 524025, PR China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Liu
authors.affiliation: Kemin Industries (Zhuhai) Co. Ltd, Zhuhai 519110, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Laboratory of Aquatic Animal Nutrition and Feed, Fisheries College, Guangdong Ocean University, Zhanjiang 524025, PR China. Electronic address: bptan@126.com.
authors.forename: Beiping
authors.initials: B
authors.lastname: Tan
authors.affiliation: Kemin Industries (Zhuhai) Co. Ltd, Zhuhai 519110, PR China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Lao
authors.affiliation: Kemin Industries (Zhuhai) Co. Ltd, Zhuhai 519110, PR China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Duan
authors.affiliation: Laboratory of Aquatic Animal Nutrition and Feed, Fisheries College, Guangdong Ocean University, Zhanjiang 524025, PR China.
authors.forename: Wuwei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Laboratory of Aquatic Animal Nutrition and Feed, Fisheries College, Guangdong Ocean University, Zhanjiang 524025, PR China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Dong
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D001412:Bacillus subtilis / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D060467:Disease Resistance / Q000276:immunology*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D008969:Molecular Sequence Data; D009113:Muramidase / Q000378:metabolism; D033561:Penaeidae / Q000254:growth & development* / Q000276:immunology* / Q000382:microbiology*; D010587:Phagocytosis / Q000276:immunology; D019936:Probiotics / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013482:Superoxide Dismutase / Q000378:metabolism; D014733:Vibrio / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D012336:RNA, Ribosomal, 16S; D013482:Superoxide Dismutase; D009113:Muramidase
keywords: Bacillus subtilis; Immunity; Litopenaeus vannamei; Pathogen; Probiotics