Effect of inulin and probiotic bacteria on growth, survival, immune response, and prevalence of white spot syndrome virus (WSSV) in Litopenaeus vannamei cultured under laboratory conditions

The effect of inulin and probiotic bacteria on the growth, survival, immune response and viral prevalence of white spot syndrome virus (WSSV) in white shrimp was evaluated. Presumptive bacilli and lactic acid bacteria (LAB) were characterized for hemolytic and enzymatic activity, hydrophobicity and antagonism against Vibrio. Selected isolates (Bacilli and LAB) were included in the diet of juvenile shrimp. Two bioassays were conducted with treatments by triplicate (10 shrimp per replicate) with inulin and inulin and bacteria. Fourteen LAB and six bacilli isolates had potential as probiotics. Survival and growth was not affected by the addition of the inulin and bacteria to diet. Inulin and bacteria improved immunity in cultured shrimp. Also, these feed additives reduced the prevalence of WSSV in cultured shrimp.Keywords: Probiotics, prebiotics, white spot syndrome virus (WSSV), immune system, Litopenaeus vannameiAfrican Journal of Biotechnology Vol. 12(21), pp. 3366-337

Isolation and characterization of infectious Vibrio sinaloensis strains from the Pacific shrimp Litopenaeus vannamei (Decapoda: Penaeidae)

10 páginas, 2 figuras, 2 tablas[EN] Infectious diseases especially those caused by bacterial and viral pathogens are serious loss factors in shrimp farming. In this study, bacteria were isolated from the gut and hepatopancreas of stressed shrimps obtained from a commercial farm. The isolates were screened on Thiosulfate citrate bile salt sucrose (TCBS) agar plates for the selection of Vibrio species. Presumptive vibrios were characterized through tests for hemolytic and enzymatic activity, hydrophobicity, growth and molecular identification. Three experimental infections were conducted in order to confirm the pathogenicity of selected bacterial strains VHPC18, VHPC23, VHPC24 and VIC30. In the third experimental challenge the LD50 was obtained, it lasted 10 days with 10 shrimp, weighing 6.9±1.1g, per tank. The treatments in triplicate were: (1) saline solution (control group); (2) 2×105CFU/shrimp; (3) 4×105CFU/shrimp; (4) 2×106CFU/shrimp; (5) 4×106CFU/shrimp, and (6) 8×106CFU/shrimp. In all challenges, water parameters measured during the experimental period remained within optimum ranges. Pathogenicity tests confirmed that the mixture of four vibrio isolates, identified as Vibrio sinaloensis, was virulent for L. vannamei. The LD50 value was 1.178×105CFU/g body weight. V. sinaloensis may act as opportunistic pathogens for cultured L. vannamei.[ES] Las enfermedades de etiología infecciosa, especialmente las causadas por patógenos bacterianos y virales ocasionan graves pérdidas en el cultivo de camarón blanco Litopenaeus vannamei. En este estudio se caracterizó: la actividad enzimática y hemolítica; hidrofobicidad; crecimiento e identificación molecular de vibrios aislados del intestino y hepatopancreas de camarones estresados, obtenidos de una granja comercial, en medio Agar Tiosulfato Citrato Bilis Sacarosa. Además, se realizaron tres infecciones experimentales para confirmar la patogenicidad de las cepas bacterianas seleccionadas VHPC18, VHPC23, VHPC24 y VIC30. En la tercera infección experimental se obtuvo la LD50, el reto duró 10 días, con 10 camarones por tanque con un peso de 6.9±1.1g. Los tratamientos se realizaron por triplicado: (1) solución salina (grupo control); (2) 2×105UFC/camarón; (3) 4×105UFC/camarón; (4) 2×106UFC/camarón; (5) 4×106UFC/camarón y (6) 8×106UFC/camarón. En todos los retos, los parámetros del agua permanecieron dentro de los intervalos óptimos. Las pruebas de patogenicidad confirmaron que la mezcla de cuatro aislados de Vibrio, identificados como Vibrio sinaloensis, fue virulenta para L. vannamei. El valor de la LD50 fue de 1.178×105UFC/g de peso corporal. Los resultados permiten establecer que las cepas de V. sinaloensis pueden actuar como patógenos oportunistas en L. vannamei cultivado.Authors are grateful to Consejo Estatal de Ciencia y Tecnología del Estado de Sinaloa (CECyT-Sinaloa) and to the Secretaría de Investigación y Posgrado del Instituto Politécnico Nacional (SIP-IPN) for financial support. Ma. del Carmen Flores Miranda acknowledges CONACYT-Mexico and SIP-IPN for the M.Sc. grantsPeer reviewe

Effect of inulin and probiotic bacteria on growth, survival, immune response, and prevalence of white spot syndrome virus (WSSV) in Litopenaeus vannamei cultured under laboratory conditions

The effect of inulin and probiotic bacteria on the growth, survival, immune response and viral prevalence of white spot syndrome virus (WSSV) in white shrimp was evaluated. Presumptive bacilli and lactic acid bacteria (LAB) were characterized for hemolytic and enzymatic activity, hydrophobicity and antagonism against Vibrio. Selected isolates (Bacilli and LAB) were included in the diet of juvenile shrimp. Two bioassays were conducted with treatments by triplicate (10 shrimp per replicate) with inulin and inulin and bacteria. Fourteen LAB and six bacilli isolates had potential as probiotics. Survival and growth was not affected by the addition of the inulin and bacteria to diet. Inulin and bacteria improved immunity in cultured shrimp. Also, these feed additives reduced the prevalence of WSSV in cultured shrimp

Microbial immunostimulants reduce mortality in whiteleg shrimp (Litopenaeus vannamei) challenged with Vibrio sinaloensis strains

The effect of microbial immunostimulants on the survival and immune response of juvenile Litopenaeus vannamei challenged with Vibrio sinaloensis strains was evaluated. Dead microorganisms were added to feed with the attractant Dry Oil® and consisted of four lactic acid bacteria (Lta2, Lta6, Lta8, and Lta10) and one yeast (Lt6). V. sinaloensis strains or saline solution were inoculated to shrimp by injection. The bioassay was conducted for 21 days with five treatments in triplicate: (I) shrimp fed with commercial feed+sterile saline solution at 2.5% NaCl (control group I); (II) shrimp feed with commercial feed+LD50 Vibrio (control group II); (III) shrimp fed daily with experimental diet+LD50 Vibrio; (IV) shrimp fed every 3 days with experimental diet+LD50 Vibrio; and (V) shrimp fed every 6 days with experimental diet+LD50 Vibrio. Shrimp (8.1±1.4 g) were cultured in 120-L plastic tanks and fed twice a day. The activity of lysosomal enzymes in plasma and hemocytes were determined with the API ZYM kit and lysoplate assay. Survival of shrimp in treatment IV was significantly higher than those of control II. Total hemocyte count in treatment III was significantly higher than control II. The activity of nine hydrolytic enzymes was found in plasma and six in the hemocyte lysate supernatant (HLS). Shrimp fed with immunostimulants every six days were not protected against V. sinaloensis. The results indicate that these microbial immunostimulants administered every three days is a good feed additive against Vibrio spp. in shrimp culture

Isolation and characterization of infectious Vibrio sinaloensis strains from the Pacific shrimp Litopenaeus vannamei (Decapoda: Penaeidae)

Infectious diseases especially those caused by bacterial and viral pathogens are serious loss factors in shrimp farming. In this study, bacteria were isolated from the gut and hepatopancreas of stressed shrimps obtained from a commercial farm. The isolates were screened on Thiosulfate citrate bile salt sucrose (TCBS) agar plates for the selection of Vibrio species. Presumptive vibrios were characterized through tests for hemolytic and enzymatic activity, hydrophobicity, growth and molecular identification. Three experimental infections were conducted in order to confirm the pathogenicity of selected bacterial strains VHPC18, VHPC23, VHPC24 and VIC30. In the third experimental challenge the LD50 was obtained, it lasted 10 days with 10 shrimp, weighing 6.9±1.1g, per tank. The treatments in triplicate were: (1) saline solution (control group); (2) 2×105CFU/shrimp; (3) 4×105CFU/shrimp; (4) 2×106CFU/shrimp; (5) 4×106CFU/shrimp, and (6) 8×106CFU/shrimp. In all challenges, water parameters measured during the experimental period remained within optimum ranges. Pathogenicity tests confirmed that the mixture of four vibrio isolates, identified as Vibrio sinaloensis, was virulent for L. vannamei. The LD50 value was 1.178×105CFU/g body weight. V. sinaloensis may act as opportunistic pathogens for cultured L. vannamei.Las enfermedades de etiología infecciosa, especialmente las causadas por patógenos bacterianos y virales ocasionan graves pérdidas en el cultivo de camarón blanco Litopenaeus vannamei. En este estudio se caracterizó: la actividad enzimática y hemolítica; hidrofobicidad; crecimiento e identificación molecular de vibrios aislados del intestino y hepatopancreas de camarones estresados, obtenidos de una granja comercial, en medio Agar Tiosulfato Citrato Bilis Sacarosa. Además, se realizaron tres infecciones experimentales para confirmar la patogenicidad de las cepas bacterianas seleccionadas VHPC18, VHPC23, VHPC24 y VIC30. En la tercera infección experimental se obtuvo la LD50, el reto duró 10 días, con 10 camarones por tanque con un peso de 6.9±1.1g. Los tratamientos se realizaron por triplicado: (1) solución salina (grupo control); (2) 2×105UFC/camarón; (3) 4×105UFC/camarón; (4) 2×106UFC/camarón; (5) 4×106UFC/camarón y (6) 8×106UFC/camarón. En todos los retos, los parámetros del agua permanecieron dentro de los intervalos óptimos. Las pruebas de patogenicidad confirmaron que la mezcla de cuatro aislados de Vibrio, identificados como Vibrio sinaloensis, fue virulenta para L. vannamei. El valor de la LD50 fue de 1.178×105UFC/g de peso corporal. Los resultados permiten establecer que las cepas de V. sinaloensis pueden actuar como patógenos oportunistas en L. vannamei cultivado