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Revista MVZ Córdoba

versão impressa ISSN 0122-0268
versão On-line ISSN 1909-0544

Rev.MVZ Cordoba vol.23 no.3 Córdoba set./dez. 2018

http://dx.doi.org/10.21897/rmvz.1373 

Originals

Assessment of homeopathic medicines on survival and antioxidant response in white shrimp Litopenaeus vannamei

Evaluación de medicamentos homeopáticos en la supervivencia y respuesta antioxidante del camarón blanco Litopenaeus vannamei infectado con Vibrio parahaemolyticus

José Mazón-Suástegui1  , Milagro García-Bernal2  , Araceli Avilés-Quevedo3  , Ángel Campa-Córdova1  , Joan Salas-Leiva1  , Fernando Abasolo-Pacheco4  * 

1 Centro de Investigaciones Biológicas del Noroeste S.C., La Paz, Baja California Sur, México.

2 Centro de Bioactivos Químicos, Universidad Central de Las Villas, Santa Clara, Villa Clara, Cuba.

3 Instituto Nacional de Pesca (INAPESCA), La Paz, Baja California Sur, México. Investigador jubilado.

4 Universidad Técnica Estatal de Quevedo, Facultad de Ciencias Agrarias, Quevedo, Ecuador.

ABSTRACT

Objective.

Evaluating the effect of homeopathic medicines on survival and activity of the superoxide dismutase (SOD) enzyme in white shrimp Litopenaeus vannamei subjected to infection with the pathogenic Vibrio parahaemolyticus.

Materials and methods.

The average lethal dosage (LD50) was determined for the pathogen strain in L. vannamei juveniles under immersion (Imm), injection (Inj) and incision + immersion (Inc+Imm) methods. Four treatments were applied: (1) Mix CIB®-HOM Heel-Mix (TH1), constituted by equal v/v ratio, of Cyme-Heel®, Gal-Heel®, Hepa-Heel®, Mucs-Heel® and Chol-Heel®; (2) Mix CIB®-HOM Pav-Mix (TH2), constituted by the same v/v ratio of Passiflora incarnata, Valeriana officinalis, Zincum valerianicum and Ignatia amara (Similia®); (3) Heel-Mix/Pav-Mix (TH3) consisting of a 1:1 v/v combination of the TH1 and TH2 treatments, and (4) ViT-Mix (TH4), constituted by Vidatox®, and a control (not treated/infected).

Results.

While applying the methods Imm, Inj and Inc+Imm, LD50 was 0.9 x 106; 0.6 x 106 and 0.5 x 106 UFC.mL-1, respectively. At the end of the challenge, the groups treated with TH2, TH3 and TH4 had a greater survival rate to that of the control group (p<0.05). Moreover, these two last treatments showed a greater SOD activity with respect to the control group (p<0.05).

Conclusions.

The homeopathic treatments (TH3 and TH4) increased survival and SOD activity in L. vannamei juveniles challenged with V. parahaemolyticus, which suggests that the homeopathic treatments employed had the potential as an alternative for the control of V. parahaemolyticus and its associated diseases, including the early mortality syndrome in shrimp farming.

Key words: Aquaculture homeopathy; shrimp; immune response; Vibrio parahaemolyticus. (Sources: CAB)

RESUMEN

Objetivo.

Evaluar el efecto de medicamentos homeopáticos sobre la supervivencia y actividad de la enzima superóxido dismutasa (SOD) del camarón Litopenaeus vannamei sometido a infección con Vibrio parahaemolyticus.

Materiales y métodos.

Se determinó la dosis letal media (DL50) para la cepa patógena en juveniles de L. vannamei, bajo los método de inmersión (Inm), inyección (Iny) e incisión + inmersión (Inc+Inm). Luego el efecto de cuatro medicamentos homeopáticos sobre juveniles de L. vannamei retados con Vibrio parahaemolyticus fue evaluado usando el índice la supervivencia y la actividad SOD. Se aplicaron cuatro tratamientos: (1) Mezcla CIB®-HOM Heel-Mix (TH1), constituido por igual proporción v/v, de Cyme-Heel®, Gal-Heel®, Hepa-Heel®, Mucs-Heel® y Chol-Heel®; (2) Mezcla CIB®-HOM Pav-Mix (TH2), constituido por igual proporción v/v de Passiflora incarnata, Valeriana officinalis, Zincum valerianicum e Ignatia amara (Similia®); (3) Heel-Mix/Pav-Mix (TH3) constituido por una combinación 1:1 v/v de los tratamientos TH1 y TH2, y (4) ViT-Mix (TH4), constituido por Vidatox®, y un control (no tratado/infectado).

Resultados.

Al aplicar los método Inm, Iny e Inc+Inm la DL50 fue de 0.9 x 106; 0.6 x 106 y 0.5 x 106 UFC.mL-1, respectivamente. Los camarones tratados con TH3 y TH4 presentaron una mayor actividad de SOD con respecto al grupo control (p<0.05). Al final del reto, los grupos TH2, TH3 y TH4 tuvieron una supervivencia mayor a la del grupo control (p<0.05).

Conclusiones.

Los tratamientos homeopáticos (TH3 y TH4), aumentaron la actividad de la enzima SOD y la supervivencia en juveniles de L. vannamei, retados con V. parahaemolyticus. Esto sugiere que los tratamientos homeopáticos empleados tienen potencial como alternativa para el control de V. parahaemolyticus y sus enfermedades asociadas, incluido el síndrome de mortalidad temprana en el cultivo del camarón.

Palabras-clave: Camarón; homeopatía acuícola; respuesta inmune; Vibrio parahaemolyticus (Fuente: CAB)

INTRODUCTION

-The shrimp Litopenaeus vannamei is a species with rapid growth, high survival and price in the market, which makes this crustacean one of the most important resources at world level 1. Nonetheless, the production of this important resource has been hindered by recurrent epizootic outbreaks and sudden mortalities caused by pathogen microorganisms, particulary to pathogenic bacteria Vibrio parahaemolyticus that causes the pathology identified as “Early Mortality Syndrome” (EMS), and later called “Acute Hepatopancreatic Necrosis Syndrome” (AHPNS) caused by a pathogenic strain of Vibrio parahaemolyticus was observed 2. This pathology occurs during the first 30 days post-harvest and could cause up to 100% mortality 3.

To face the challenge, several chemical and antibiotic products have usually been applied 4, whose prophylactic application was initially an effective strategy. However, they have caused the development of resistant bacteria making it necessary to reduce their application 5. These problems have led the shrimp culture industry to explore and develop new strategies that would be as effective or better than antibiotics but respectful to the environment and consumers, and above all sustainably applicable in the medium and long term 6. As part of the search for new options, homeopathy has been confirmed as an alternative with the potential of disease control in farming aquatic and terrestrial animals 7. It has been catalogued as a complementary medication that uses high dilutions of substances that derive from plants, minerals, or animals, and it is based on the similarity principle 8. The animals could benefit from the use of homeopathic products because they stimulate their immune system and specific organic responses 9. Besides contributing preventively by reducing stress, homeopathic treatments can also reduce the application of chemotherapeutic agents and antibiotics avoiding risks for cultured animals, consumers, and the environment 10.

Taking this background into account, the objective of this study was to assess the effect of homeopathic medication on survival and antioxidant response in L. vannamei before infection with V. parahaemolyticus.

MATERIALS AND METHODS

Study site. The experiment was performed in the Mollusc Laboratory of Centro de Investigaciones Biológicas del Noroeste (CIBNOR) in La Paz, Baja California Sur, México. Juveniles of L. vannamei (8 ± 0.05 g) were obtained from the commercial shrimp laboratory of the company Acualcultura Mahr located in Puerto de Pichilingue, La Paz, México. The shrimp were acclimated in 1500-L fiberglass tanks with filtered seawater at 1 µm and sterilized with UV light, salinity of 37 g L-1, continuous airflow and temperature of 29 ± 0.5°C for five days. The organisms were fed ad libitum three times a day with a balanced diet (Alimento PIASA®, Planta La Paz, B.C.S., México, 35% protein).

Bacterial strains. For the survival study, the strain Vibrio parahaemolyticus (CIAD-CAIM 170) was used; it was cultivated in tryptone soy broth (TSB; #257107, Difco) at 35°C for 48 h. The culture was centrifuged at 4696 g at 4°C for 10 min; the pellet was re-suspended in sterile seawater, and bacterial density was adjusted to 1.0 to obtain a final density of 1 x 109 UFC mL-1 (11.

Pathogen inoculation and average lethal dosage (LD 50) in Litopenaeus vannamei . To determine LD50, a batch of shrimp was infected in groups in triplicate by means of three inoculation methods: [immersion (Imm), injection (Inj) and incision + immersion (Inc+Imm)]. For each infection method, three groups (10 shrimp each) were formed with different concentrations (103, 105, 107) of V. parahaemolyticus. For Imm, the shrimp were placed in water at the pathogen concentrations previously mentioned. For Inj the shrimp were injected in the third abdominal segment with 30 µL of each one of the bacterial concentrations already mentioned 12. For Inc+Imm, two incisions of approximately two mm in length were performed through the cuticle and the muscle of the third abdominal muscle. Then, the shrimp were immersed in seawater with the pathogen at the concentrations mentioned 13. After infection was performed, mortality was recorded in each group and replicate for the following 48 h to determine the average lethal dosage (LD50) by applying the Probit analysis 14.

Preparation of homeopathic medication. The experimental treatments were prepared starting from the commercial homeopathic medicine for humans, ingestible in alcoholic dilution 30 Centesimal Hahnemaniana (30 CH) of the Laboratorios Similia® (México), Labiofam® (Cuba), and Heel® in injectable aqueous dilution of Laboratorios Rubiopharma® (México). The treatments were prepared by combining the required volume with the respective “stock dynamisation” (30 CH) of each one of their components diluted in a proportion of 1:99 to obtain “work dynamisation” (31 CH) utilizing ethanol 30oGL as vehicle, which was prepared by diluting ethanol 87oGL (Similia®, México) in distilled water.

Experimental treatments. Four treatments were used 1 Mix CIB®-HOM Heel-Mix (TH1) constituted by an equal v/v proportion of Cyme-Heel®, Gal-Heel®, Hepa-Heel®, Mucs-Heel® and Chol-Heel®; (2) Mix CIB®-HOM Pav-Mix (TH2) constituted by equal v/v proportion of Passiflora incarnata, Valeriana officinalis, Zincum valerianicum and Ignatia amara (Similia®); (3) Heel-Mix/Pav-Mix (TH3) constituted by a proportion of 1:1 v/v combination of the treatments TH1 and TH2; and (4) ViT-Mix (TH4) constituted by Vidatox®. Additionally, a fifth experimental group was included as control (non-treated/non-infected). The homeopathic treatments (31CH) prepared with ethanol 30oGL were interspersed (5% volume/weight) in pelletized commercial feed with 35% protein (PIASA®, Planta La Paz, B.C.S. México), provided ad libitum for seven days previous to and also during challenge. The same type of food was used for the control group, but in this case it was interspersed with ethanol 30oGL.

During the sequential dynamisation process, the dilution at 1:99 was alternated with shaking in vortex equipment (Benchmark mixer™, Benchmark Scientific Inc. Edson, NJ, U.S.A.) at 3200 rpm for two minutes applying basic principles of homeopathic pharmacopoeia. Independently of its origin, all “work” (31 CH) dynamisations were prepared utilising ethanol 30oGL as vehicle to homogenise alcoholic content in all treatments since the medication Vidatox® (La Habana, Cuba) vehicle is ethanol 30oGL.

Experimental design. The juveniles of L. vannamei were distributed randomly (10 shrimp/group) in 4 L experimental units gauged with 2 L of filtered seawater and disinfected with UV at 29 ± 0.5°C with constant aeration and photoperiod of 12:12 h. These units were covered with lids under pressure fitted with an opening of 5 x 5 cm (with mosquito mesh). Such recipients were placed in a thermoregulated system at 29 ± 1°C within plastic boxes with chlorinated drinking water. The shrimp were fed the interspersed commercial diet ad libitum with the respective homeopathic treatments and with 30oGL ethanol for control three times a day. Particulate bottom matter of the tubs was eliminated daily by siphoning, recovering the volume (25%) of eliminated water immediately. The treatments were administered for seven days, and a challenge bioassay started from the eighth day with a total length of 120 h.

Challenge with Vibrio parahaemolyticus . After seven days of treatment, we proceeded to challenge the shrimp with the pathogen. For this purpose, five experimental groups were formed (10 shrimp per group) and three replicates, which were placed separately in 4-L experimental units and gauged with 2-L filtered and sterilised seawater. All the groups were challenged with the pathogen V. parahaemolyticus, corresponding to the diet LD50 (obtained in the previous assays) except for the control group.

Determination of SOD activity. At 70 h after starting the challenge, nine shrimp from each experimental group were selected at random. Muscular tissue (100 mg) was taken from these juveniles and submerged in 500 µL of phosphate-buffered saline (PBS) pH 7.5 for subsequent determination of superoxide dismutase (SOD) activity. The sampled tissue was processed with a tissue homogeniser (Toption, model JS18, Xi’an, China). The homogenised tissue was centrifuged at 9327 g at 4ºC for 10 min; once the supernatant was recovered, it was stored at -20ºC for its subsequent assessment. The SOD activity was determined using a commercial kit (SOD Assay Kit-WST #19160, Sigma-Aldrich, St. Louis, MO, U.S.A.), following the instructions of the manufacturer. The results were expressed as inhibition percentage of complex formation WST-1 (water-soluble tetrazolium) formazan 15.

Statistical analysis. The data obtained were used in Kolmogorov-Smirnov test to verify normality, and Levene’s test was used to analyse equality of variances. Arcsine transformation was applied to the data expressed as percentage (survival and SOD) before performing ANOVA. Tukey multiple comparison of means tests were performed to detect significant differences among the enzymatic SOD activity and survival values obtained in each one of the treatments. The differences were considered significant for P < 0.05. All the analyses were performed by the statistical program SPSS version 21 for Windows (SPSS Inc., Chicago II).

RESULTS

During the determination of LD50, the percentage of accumulated mortality of L. vannamei was obtained 48 h post-infection by using different methods of infection and charge of V. parahaemolyticus (Table 1). The LD50 results were 0.9 x 106 CFU mL-1 with the immersion method; 0.6 x 106 CFU mL-1 with the injection method; and 0.5 x 106 CFU mL-1 with the incision + immersion method (Table 1). The dosage selected for the experimental challenge was the one that showed a mortality of 50% by the immersion method to avoid possible collateral effects of the incision.

Table 1 Mortality accumulated and LD50 in Litopenaeus vannamei juveniles challenged with Vibrio parahaemolyticus at 48 h post-infection, using different methods to determine average lethal dosage. 

At the end of the challenge, 120 h post-infection, the groups treated with TH2, TH3 and TH4 showed significantly higher survival rates (P < 0.05) than the control group (Figure 1). The highest survival rates corresponded to TH3 and TH4 64.43% and 56%, respectively. The group treated with TH1 and the control group, showed an accumulated survival of 0% when the pathogen challenge concluded at 120 h (Figure 1).

Figure 1 Survival of Litopenaeus vannamei juveniles treated with homeopathic medications during challenge (120 h) with Vibrio parahaemolyticus. Letters a, b, c indicate statistical differences between treatments and control. 

With respect to SOD activity in shrimp L. vannamei tissue at 72 h after challenge, the groups treated with TH1 and TH2 did not show significant differences (34.48 ± 1.87 and 16.32 ± 1.22, respectively) in relation to the control group (41.63 ± 2.59); whereas TH3 and TH4 showed a SOD activity of 86.43 ± 1.02 and 83.47 ± 5.54, respectively, with significantly higher values (P < 0.05) with respect to the control group (41.63 ± 2.59) after challenge with V. parahaemolyticus (Figure 2).

Figure 2 Activity of SOD enzyme in white shrimp Litopenaeus vannamei juveniles treated with homeopathic treatments at 72 h after starting challenge with Vibrio parahaemolyticus. Data were expressed as media ± standard deviation. Columns with different letters show difference (p<0.05). 

DISCUSSION

Homeopathic medications are natural substances of animal, plant or mineral origin, highly diluted and agitated, and thus sufficiently innocuous 7, which could activate specific sensibility mechanisms in living organisms, and they do not contravene their natural defence reactions 8. Homeopathy has been used with success in aquaculture 16,17, and it has the applicability to reduce stress associated to a gradual and progressive intensification, which is habitual in modern aquaculture production systems 7,16.

The lesions and stress that cultured shrimp may suffer under adverse environmental conditions reduce their natural resistance, making them susceptible to viral and/or bacterial infections 18. In shrimp, natural infection by virulent bacteria is made by different routes: oral, transcuticular or by lesions, and it could be associated with an imbalance of their normal intestinal microbiota 19. The average lethal dosage (LD50) was established to determine virulence of the pathogen strain, and it has been used to evaluate shrimp resistance or susceptibility to vibriosis 11. This study selected the LD50 of 0.9 x 106 UFC mL-1 by the immersion method because it was the least aggressive method of infection with less collateral effects that imitates the natural conditions that shrimp are exposed to the bacteria present in the marine environment 20.

The marine invertebrates, including shrimp, have developed an immune innate system based mainly in phagocytosis and generation of antimicrobial peptides and reactive oxygen species (ROS) 21. Because ROS, in their majority superoxide anions, can also affect the host tissues; invertebrates counterattack their effect by producing diverse compounds, including SOD enzymes, catalase and glutathione peroxidase 22. The activity of SOD has been referenced as a parameter to evaluate the potential of the immune system in some shrimp species 23,24.

This study has demonstrated that in the L. vannamei juveniles treated with the homeopathic treatments TH3 and TH4, the SOD enzyme activity increased significantly at 70 h post-infection with V. parahaemolyticus with respect to the control group. Whereas shrimp treated with TH1 and TH2, their response was similar to that of the control group. Treatment TH3 included the formulation of the medication Passival®, used in human medicine as tranquiliser to reduce stress and improve sleep besides the mixture Heel-Mix, which included medication used for enzymatic disorder, infectious diseases and stimulation of organism defence. Treatment TH4 is a homeopathic medication whose active principle is the venom of the Rhopalurus junceus scorpion, an endemic species to Cuba. Anti-tumour properties have been attributed to this medicine shown through some preclinical toxicity studies 25 on tumour cells of epithelial origin 26 and an immunomodulatory effect that increases production of white cells and interleukins 27.

The greatest survival recorded in animals that received treatments TH2, TH3 and TH4 after V. parahaemolyticus challenge indicated a protector effect, which shows that the homeopathic medications assessed could be an alternative tool for controlling bacterial diseases in shrimp farming. In relation to this study, the bacteria of the genus Vibrio are well known as pathogens of marine shrimp, so it is possible to assume that a greater survival of the shrimp treated with homeopathic medications is related to the stimulation of their immunological systems, and in consequence to a greater resistance to acute infectious diseases associated to this genus, for example, the early mortality syndrome or acute hepatopancreatic necrosis syndrome (EMS/AHNPS) 28,29.

In conclusion the homeopathic medicine included in the treatments TH3 and TH4, increased survival and immunity of the shrimp L. vannamei juveniles when infected with V. parahaemolyticus. These results contribute to the generation of new knowledge that helps to confirm that aquaculture homeopathy is a potential and eco-sustainable alternative facing the use and abuse of chemotherapeutic agents and antibiotics used to attack certain pathogens, including EMS/AHNPS increasing productivity in shrimp industry at world level.

Acknowledgements

This study was financed by Proyectos Ciencia Básica SEP-CONACYT/CIBNOR-258282 and PROINNOVA-CONACYT/PEASA-241777 under the responsibility of JMMS. The authors are thankful to the support of the governments of Cuba and Mexico, Empresa Acuacultura Mahr and CIBNOR technical staff Norma Ochoa, Delfino Barajas, Pablo Ormart, Pablo Ormart, Carmen Rodríguez, Eulalia Meza and Arturo Sierra, and to Diana Fischer for editorial services in English.

REFERENCES

1. Valdez G, Díaz F, Re AD, Sierra E. Efecto de la salinidad sobre la fisiología energética del camarón blanco Litopenaeus vannamei (Boone). Hidrobiológica 2008; 18(2):105-115. [ Links ]

2. Soto-Rodriguez SA, Gomez-Gil B, Lozano-Olvera R, Betancourt-Lozano M, Morales-Covarrubias MS. Field and experimental evidence of Vibrio parahaemolyticus as the causative agent of acute hepatopancreatic necrosis disease (AHPND) of cultured shrimp (Litopenaeus vannamei) in northwestern Mexico. Appl Environ Microbiol. 2015; 81(5):1689-1699. [ Links ]

3. Schryver PD, Defoirdt T, Sorgeloos P. Early mortality syndrome outbreaks: a microbial management issue in shrimp farming? PLoS Pathog. 2014; 10(4):e1003919. [ Links ]

4. Newaj-Fyzul A, Austin B. Probiotics, immunostimulants, plant products and oral vaccines, and their role as feed supplements in the control of bacterial ?sh diseases. J Fish Dis. 2015; 38(11):937-955. [ Links ]

5. Lakshmi B, Viswanath B, Sai Gopal DVR. Probiotics as antiviral agents in shrimp aquaculture. J Pathog. 2013; ID: 424123. [ Links ]

6. Standen BT, Rawling MD, Davies SJ, Castex M, Foey A, Gioacchini G. Probiotic Pediococcus acidilactici modulates both localised intestinal- and peripheral-immunity in tilapia (Oreochromis niloticus). Fish Shellfish Immun. 2013; 35(4):1097-1104. [ Links ]

7. Ortiz-Cornejo NL, Tovar-Ramírez D, Abasolo-Pacheco F, Mazón-Suástegui JM. Homeopatía, una alternativa para la acuicultura. Rev Med Homeopat. 2017; 10(1):18-24. [ Links ]

8. Khuda-Bukhsh AR, Pathak S. Homeopathic drug discovery: theory update and methodological aspect. Expert Opinion Drug Discovery. 2008; 3(8):979-990. [ Links ]

9. Vockeroth WG. Veterinary homeopathy: an overview. Can Vet J. 1999; 40(8):592-594. [ Links ]

10. Siena CE, Natali MRM, Braccini GL, Oliveira AC, Ribeiro RP, Vargas L. Effect of core homeopathic homeopatila 100(r) in productive efficiency of fingerlings reverted from Nile tilapia (Oreochromis niloticus). Semina: Ciênc Agrár. 2010; 31(4):985-994. [ Links ]

11. Luis-Villaseñor IE, Voltolina D, Gomez-Gil B, Ascencio F, Campa-Córdova ÁI, Audelo-Naranjo JM, Zamudio-Armenta OO. Probiotic modulation of the gut bacterial community of juvenile Litopenaeus vannamei challenged with Vibrio parahaemolyticus CAIM 170. Lat Am J of Aquat Res. 2015; 43(4):766-775. [ Links ]

12. Takahashi Y, Itami T, Kondo M, Maeda M, Fujii R, Tomonaga S, Supamattaya K., Boonayaratpalin S. Electron microscopic evidence of bacilliform virus infection in kuruma shrimp (Penaeus japonicus). Fish Pathology. 1994; 29:121-125. [ Links ]

13. Flegel TW. (ed) Advances in shrimp biotechnology. National Center for Genetic Engineering and Biotechnology, Bangkok: Mahidol University; 1998. [ Links ]

14. Finney DJ. Probit analysis: a statistical treatment of the sigmoid response curve. 2nd. Cambridge University Press: Cambridge; 1952. [ Links ]

15. Dudonné S, Vitrac X, Coutière P, Woillez M, Mérillon JM. Comparative study of antioxidant properties and total phenolic content of 30 plant extracts of industrial interest using DPPH, ABTS, FRAP, SOD, and ORAC assays. J Agric Food Chem. 2009; 57(5):1768-1774. [ Links ]

16. Mazón-Suástegui JM, García-Bernal M, Saucedo PE, Campa-Córdova Á, Abasolo-Pacheco F. Homeopathy outperforms antibiotics treatment in juvenile scallop Argopecten ventricosus: effects on growth, survival, and immune response. Homeopathy. 2017; 106(1):18-26. [ Links ]

17. Merlini LS, Vargas L, Piau R, Ribeiro PR, Merlini NB. Effects of a homeopathic complex on the performance and cortisol levels in Nile tilapia (Oreochromis niloticus). Homeopathy. 2014; 103:139-142. [ Links ]

18. Gómez B, Roque A, Guerra AL. Enfermedades Infecciosas más comunes en la camaronicultura en México y el impacto del uso de antimicrobianos. Instituto de Ciencias del Mar y Limnología: México; 2001. [ Links ]

19. Saulnier D, Haffner P, Goarant C, Levy P, Ansquer D. Experimental infection models for shrimp vibriosis studies: a review. Aquaculture. 2000; 191:133-144. [ Links ]

20. Aguirre-Guzmán G, Sánchez-Martínez JG, Pérez-Castañeda R, Palacios-Monzón A, Trujillo-Rodríguez T, De La Cruz-Hernández NI. Pathogenicity and Infection Route of Vibrio parahaemolyticus in American White Shrimp, Litopenaeus vannamei. J World Aquac Soc. 2010; 41:464-470. [ Links ]

21. Lemaitre B, Hoffmann J. The host defense of Drosophila melanogaster. Annu Rev Immunol. 2007; 25:697-743. [ Links ]

22. Fridovich I. Oxygen toxicity: a radical explanation. J Exp Biol. 1998; 201:1203-1209. [ Links ]

23. Franco, R., Martín, L., Arenal, A., Santiesteban, D., Sotolongo, J., Cabrera, H., Castillo, N. M. Evaluation of two probiotics used during farm production of white shrimp Litopenaeus vannamei (Crustacea: Decapoda). Aquac Res. 2017; 48(4):1936-1950. [ Links ]

24. Liu, G., Zhu, S., Liu, D., Guo, X., Ye, Z. Effects of stocking density of the white shrimp Litopenaeus vannamei (Boone) on immunities, antioxidant status, and resistance against Vibrio harveyi in a biofloc system. Fish Shellfish Immun. 2017; 67:19-26. [ Links ]

25. Díaz-García A, Morier-Díaz L, Frión-Herrera Y, Rodríguez-Sánchez H, Caballero-Lorenzo Y, Mendoza-Llanes D, Riquenes-Garlobo Y, Fraga-Castro JA. In vitro anticancer effect of venom from Cuban scorpion Rhopalurus junceus against a panel of human cancer cell lines. J Venom Res. 2013; 4:5-12. [ Links ]

26. Díaz A, Morier L, Rodríguez H, Caballero Y. Citotoxicidad del veneno del escorpión cubano Rhopalurus junceus y sus fracciones sobre líneas celulares tumorales humanas. LABIOFAM. 2010; 1:12-18. [ Links ]

27. Hernández Betancourt O, Casado Hernández I, Iglesias Huerta E, Ramírez Labrada A, Del Risco Ramos J, Rodríguez Pargas A. Evaluación de la toxicidad in vitro del veneno del alacrán Rhopalurus junceus a través de un ensayo celular. Rev Cubana de Invest Bioméd. 2009; 28(1):1-11. [ Links ]

28. Akazawa N, Eguchi M. Environmental trigger for EMS/ AHPNS identified in Agrobest shrimp ponds. Glob Aquacult Advocate. 2013; 4:16-17. [ Links ]

29. Hoanh DTH, Phu TQ, Phuong NT, Tuan PA. Ongoing Vietnam studies find Vibrio with phage transmits EMS/AHPNS. Glob Aquacult Advocate. 2013; 4:22-23. [ Links ]

Recebido: Novembro de 2017; Aceito: Junho de 2018

* Correspondence: fabasolo@uteq.edu.ec

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