Abstract Invertebrates’ immune defense mechanisms play a critical role in pathogen recognition and elimination. De novo assembly and annotation of the Argopecten ventricosus transcriptome were performed for the immune-related gene identification. Scallops (height: 4.4 cm) were challenged with inactivated Vibrio parahaemolyticus IPNGS16. The RNA from different tissues was pooled for a single cDNA library construction sequenced by NextSeq 500 platform 2×75 paired‐end chemistry. Before de novo assembling with Trinity, reads were analyzed with FastQC, Trimmomatic, and Prinseq. Assembled sequences were analyzed by CD-HIT-EST and TransDecoder. The corresponding annotation was performed against NCBI-nr, RefSeq protein, and KAAS (KEGG) databases. The Trinity assembly yielded 107,516 contigs. TransDecoder yielded 25,285 sequences as CDSs of which, 16,123 were annotated against the NCBI-nr protein, most of them scored with Crassostrea gigas data. Gene ontology mapped sequences (15,262) were classified in molecular functions (∼13,000), cellular components (∼11,000), and biological processes (∼13,000). The KAAS analysis showed biological categories for metabolism (13%), cellular processes (12%), genetic information processing (10%), organismal systems (19%), environmental information (13%), and human diseases (33 %). Within the organismal systems, 467 immune-related genes (KO) were identified. Sixty-four immune-related genes were annotated/blasted against the NCBI-nr and RefSeq protein databases. An RT-qPCR was performed to analyze the expression level of immune-related genes obtained in the transcriptome analysis in scallops (height 4.5 cm) treated with probiotic bacilli added to culture water. Bacilli significantly increased the expression of the HSP70 and PGRP genes. The gene transcripts analysis of A. ventricosus will better understand its immune response against pathogens in culture systems.

ABSTRACT The effect of dietary inulin on the intestinal bacterial communities of Penaeus vannamei by 16S metagenomic analysis was assessed. PCR amplified the V3 region of the bacterial 16S rDNA. Sequencing reads were generated using the 2×150 (300 cycles) for the base-read length chemistry of the Illumina MiniSeq platform. The software Shaman and MicrobiomeAnalyst were used to analyze the sequences. The phylum Proteobacteria and the genus Vibrio were among the most abundant taxonomic ranks for control and inulin treatment. The relative abundance of the phylum Bacteroidetes and genus Ruegeria was lower in inulin treatment concerning the control condition. Alpha and beta indices did not show significant differences between inulin treatment and control conditions. For all samples, most of the bacterial organisms showed the presence of carbohydrate and amino acid metabolism-related genes, and to a lesser extent, of energy, lipid, and cofactors and vitamin metabolism-related genes. The principal metabolic functions were glycine, serine, threonine, glyoxylate and dicarboxylate, purine, pyrimidine, pyruvate, and quorum sensing. The interaction network analysis showed fewer interactions in the inulin treatment concerning control condition. Proteobacteria, Bacteroidetes, Vibrio, and Ruegeria predominated in all samples, and inulin did not change the net microbial diversity in the intestine of P. vannamei. Streptomyces, Roseobacter, and Ruegeria showed negative interactions with Vibrio, suggesting their use as probiotics. This study sheds light on the inulin supplement on the essential role of microbiota in the shrimp.

Abstract Background: Volunteer plants have been considered as a problem in crop areas as a possible disease reservoir, but also of microorganism diversity. Mycotrophic plants, such as maize may allow preserving mycorrhizal inoculum. The ecological preservation area La Uba, in Guasave, Sinaloa, is a relictual area of vegetation of low deciduous forest and studies of its soil microbiota are scarce. This region has been recently converted to agricultural soils. This is why we studied a contiguous transition zone. Objective: To establish the diversity of arbuscular mycorrhizal fungi (AMF) present in the rhizosphere and roots of volunteer maize plants in the transition zone contiguous to La Uba. Methods: Volunteer maize roots and soil were collected once in between agricultural cycles in a transition zone. Genomic DNA was extracted from AMF colonized maize roots and soil spores; the ITS region of the ribosomal DNA was amplified and massively sequenced. Results and conclusions: A total of twelve species of AMF were found, belonging to the genera Glomus, Rhizophagus, Funneliformis y Gigaspora.; Glomus was the most abundant genus. Glomus indicum was reported for the first time in Mexico. Volunteer maize plants may assist in conserving AMF inoculum in crop soils.

Resumen Antecedentes: Las plantas voluntarias se consideran un problema en suelos de cultivo como posible reservorio de enfermedades, pero también de diversidad de microorganismos. Plantas micotróficas como el maíz permitirían preservar inóculos micorrízicos. La zona de preservación ecológica La Uba, en Guasave, Sinaloa, es un relicto de vegetación de selva baja caducifolia y su microbiota ha sido poco estudiada. Esta región ha sido reconvertida a suelo agrícola, por lo que estudiamos una zona de transición aledaña. Objetivo: Establecer la diversidad de hongos micorrízicos arbusculares (HMA) presentes en rizósfera y raíces de plantas voluntarias de maíz en una zona de transición contigua a La Uba. Métodos: Se colectaron raíces de maíz de plantas voluntarias y suelo una vez, entre ciclos agrícolas en una zona de transición. Se extrajo ADN genómico de raíces colonizadas con HMA y esporas del suelo, se amplificó y se secuenció masivamente el ITS del ADN ribosomal. Resultados y conclusiones: Se encontraron un total de 12 especies de HMA, pertenecientes a los géneros Glomus, Rhizophagus, Funneliformis y Gigaspora; siendo Glomus el más abundante. Glomus indicum se reporta por primera vez en México. Las plantas voluntarias de maíz pueden servir como reservorio de inóculo de HMA en suelos agrícolas.

Resumen Antecedentes: El virus del síndrome de la mancha blanca (WSSV) ocasiona alta mortalidad en acuacultura. El empleo de inmunoestimulantes incrementa la resistencia de los animales. Objetivo: Evaluar el porcentaje de infección de WSSV y el efecto inmunoestimulante de bacterias ácido lácticas y levadura (MI= inmunoestimulantes microbianos) en Litopenaeus vannamei infectado con WSSV. Métodos: Se realizó un bioensayo durante 33 días con tratamientos por triplicado. Se agregó MI al alimento (8,5 mg/kg de alimento), suministrandolo al camarón (9,9 ± 3,1 g) diariamente, cada 2, o cada 3 días. Los camarones se infectaron con WSSV a los 9 y 19 días. Se estudió la expresión de cuatro genes relacionados con el sistema inmune utilizando qRT-PCR. Resultados: No hubo diferencias significativas en el crecimiento y la sobrevivencia entre los tratamientos. Al final del bioensayo, el porcentaje de infección de WSSV (baja carga viral) disminuyó un 8,3 y un 25% en los tratamientos III y IV en comparación con el grupo control. Los tratamientos con MI mostraron diferencias significativas en la expresión relativa de los genes LvToll, transglutaminasa, y profenoloxidasa cuando se suministró MI diariamente en comparación con el grupo control. Los MI no regularon la expresión del gen de la superóxido dismutasa. El porcentaje de infección de WSSV disminuyó cuando el alimento con MI se aplicó cada 3 d. Conclusiones: Los MI disminuyen el porcentaje de infección de WSSV en L. vannamei infectado con baja carga viral cuando se aplican cada tres días. Además, los MI causan una sobre-expresión de los genes LvToll, Tgase y proPO cuando se administran diariamente. Se necesita más investigación sobre los inmunoestimulantes microbianos como tratamiento profiláctico contra WSSV en granjas comerciales de camarón.

Abstract Background: The white spot syndrome virus (WSSV) causes high mortalities in aquaculture. The use of immunostimulants increases animal resistance. Objective: To evaluate the WSSV infection percentage and the immunostimulant effect of lactic acid bacteria and yeast (MI= microbial immunostimulants) on WSSV infected Litopenaeus vannamei. Methods: A bioassay was performed for 33 d, with treatments in triplicate. The MI was added to the feed at 8.5 mg/kg feed and offered to shrimp (9.9 ± 3.1 g) daily, every 2 days, or every 3 days. Shrimp were infected with WSSV at 9 and 19 days. The expression of four immune system-related genes was studied using qRT-PCR. Results: No significant differences were observed in growth and survival among treatments. At the end of the bioassay, WSSV infection percentage (low viral load) decreased 8.3 and 25% in treatments III and IV as compared to the control group. Treatments with MI showed significant differences in the relative expression of LvToll, transglutaminase, and prophenoloxidase genes when MI was offered daily as compared to the control group. The MI did not regulate the expression of the superoxide dismutase gene. The WSSV infection percentage decreased when feed with MI was offered every 3 d. Conclusion: The MI decrease WSSV infection percentage in L. vannamei infected with low viral load when it is offered every three days. The MI up-regulates LvToll, Tgase, and proPO genes when it is offered daily. Further research is needed regarding prophylactic treatment with microbial immunostimulants against WSSV in commercial shrimp farms.

Resumo Antecedentes: O vírus da mancha branca (WSSV) causa alta mortalidade na aqüicultura e o uso de imunoestimulantes aumenta a resistência em animais. Objetivo: Este trabalho avaliou a prevalência do WSSV e o efeito imunoestimulante de bactérias ácido lácticas e levadura (MI= inmunoestimulantes microbianos) em Litopenaeus vannamei infectado con WSSV. Métodos: Se realizou um bioensayo durante 33 dias com tratamientos por triplicado. Se agregou MI al alimento (8,5 mg/kg feed) e se o fornecimento de camarão (9,9 ± 3,1 g) diariamente, cada 2 e cada 3 d. Los camarones foram infectados com WSSV a los 9 y 19 d. Se estudió a expressão de quatro genes relacionados com o sistema imune, use qRT-PCR. Resultados: No hubo diferencias significativas no crescimento e na supervisão entre os tratamientos. Al final del bioensayo, a prevalência do WSSV diminuiu um 8.3 e não 25% nos tratamentos III e IV em comparação com o grupo de controle. Os tratamentos com MI mostraram diferenças significativas na expressão relativa dos genes. LvToll, transglutaminasa e prophenoloxidase quando se administraron em diários de MI em comparação com o controle de grupo. Los MI não regularam a expressão do genótipo da superóxido dismutasa. A prevalência do WSSV diminuiu quando o alimento com MI se aplicó cada 3 d. Conclusões: Los IM diminuir a prevalência de WSSV em L. vannamei infectado com baixa carga viral quando aplicável a cada três dias. Além disso, os IM causaram uma sobre-expressão dos genes LvToll, Tgase e proPO quando se administran diariamente. Há mais informações sobre imunoestimulantes microbianos como tratamento profiláctico contra WSSV en granjas comerciales de camarón.

ABSTRACT Survival was investigated in Penaeus vannamei fed with powdered plants (PP: garlic, echinacea, ginger, and basil) and challenged with white spot syndrome virus (WSSV) and Vibrio parahaemolyticus by ingestion and immersion, respectively. PP was added to commercial feed at a concentration of 1, 2 and 4 g kg−1. The infection with both pathogens was made at the same time. Shrimp fed with PP (4 g kg feed−1) at different frequencies showed higher survival (96.7%) as compared to the positive control group not fed with PP (6.7%). WSSV prevalence in live and dead shrimp was similar in all treatments challenged with both pathogens varying from 33.3 to 55%. PP protects shrimp against WSSV and V. parahaemolyticus. Therefore, further research about the effect of PP is necessary for commercial shrimp farms.

ABSTRACT: The size structure of Callinectes arcuatus was determined from 2,786 ind (1,956 males and 830 females) of C. arcuatus, which were collected from March 2012 to March 2013 in El Colorado Lagoon, Sinaloa, Mexico. Sampling was random in grid form considering five stations located within the study area. Measurements of length (CL), the width of the carapace (CW) and total weight (TW) were registered. The average carapace width of C. arcuatus was 9.4 ± 0.03 cm with a minimum of 5.3 cm and a maximum of 19.5 cm. For the length of the carapace (CL) the mean was 4.8 ± 0.02 cm with a minimum of 2.8 cm and a maximum of 9.2 cm, while the total weight varied between 16 and 416 g with an average of 54.0 ± 0.71 g, in both sexes (juveniles and adults).The morphometric relationships between CL-CW were adjusted a linear model. The equation is describing the relation TW-CW, which was adjusted to a potential model with a coefficient of determination of R2 = 0.71. The growth parameters estimated using the model of von Bertalanffy, for males was K = 0.84 yr-1 y CW∞ = 14.0 cm while for females K = 0.55 yr-1 and CW∞ = 15. 6 cm. According to the results obtained, it is observed that the organisms with sizes and maximum weights were presented in juvenile and adult males in C. arcuatus, being slightly larger and heavier than females in similar sizes and according to the growth curves the organisms, this species reaching is the maximum length between 3-4 years old.

Abstract Background: Knowledge of growth is relevant because it provides information on the local dynamics of the population. Goals: This study evaluated the growth, size structure, morphometry, and sex ratio of C. bellicosus crab caught in the El Colorado lagoon, Ahome, Sinaloa, Mexico. Methods: Through size distributions and by the modal-progression method using the FISAT II program. Similarly, the growth parameters of the von Bertalanffy stationalized equation and the growth performance or Munro index (Ø) were determined from March 2012 to March 2013. Results: 3,242 organisms of C. bellicosus were captured of which 1,770 were males and 1,472 were females. The population of C. bellicosus in the lagoon ranged in size from 40 mm to 190 mm (CW), showing two similar modes for males and females (100 mm and 110 mm, respectively). The relationships between CL-CW for both sexes were adjusted to a linear type model (males, CL = 0.5265CW-0.0539, R2 = 0.8058, p <0.05, females, CL = 0.581CW-0.6335, R2 = 0.7643, p <0.05). The CW-TW relationship was of potential type (males, TW = 0.561AC3.0751, R2 = 0.7968, p <0.05; females, TW = 0.0834C2.9077, R2 = 0.7589, p <0.05). In females, K = 0.90 years-1 and L∞ = 169 mm, K = 1.20 years-1 and L∞ = 178.5 mm. Conclusions: The growth curves suggest that C. bellicosus reaches its maximum length at 2.5 to 3 years. The sex ratio of 0.81 F : 1 M was significant (X2 (0.05, 11) = 19.675, X2 observada = 58.481, p < 0.05).

Resumen Antecedentes: El conocimiento del crecimiento en cualquier especie es relevante debido a que proporciona información de la dinámica local de la población. Objetivos: Evaluar el crecimiento, la estructura de tallas, la morfometría y la proporción de sexos de las jaibas C. bellicosus capturadas en la laguna El Colorado, Ahome, Sinaloa, México. Métodos: Durante el periodo de marzo de 2012 a marzo de 2013 se evaluaron las distribuciones de frecuencias de tallas y se aplicó el método de progresión modal mediante el programa FiSAT II. Asimismo, se determinaron los parámetros de crecimiento de la ecuación de von Bertalanffy y el desempeño del crecimiento o índice de Munro (Ø). Resultados: Se capturaron 3,242 organismos de C. bellicosus, de los cuales 1,770 fueron machos y 1,472, hembras. La población de C. bellicosus en la laguna presentó un intervalo de tallas de 40 mm a 190 mm (AC), mostrando dos modas similares para machos y hembras (100 mm y 110 mm, respectivamente). Las relaciones entre el LC-AC para ambos sexos se ajustaron a un modelo de tipo lineal (machos, LC = 0.5265AC-0.0539, R2= 0.8058, p <0.05; hembras, LC = 0.581AC-0.6335, R2 = 0.7643, p <0.05). La relación AC-PT fue de tipo potencial (machos, PT = 0.561AC3.0751, R2 = 0.7968, p <0.05; hembras, PT = 0.0834AC2.9077, R2 = 0.7589, p <0.05). En hembras se estimó una K= 0.90 años-1 y L∞ = 169 mm, en los machos fue K = 1.20 años-1 y L∞ = 178.5 mm. Conclusiones: Las curvas de crecimiento sugirieron que C. bellicosus alcanzó su longitud máxima de 2.5 a 3 años. La proporción de sexos de 0.81 H : 1 M fue significativa (X2 (0.05, 11) = 19.675, X2 observada = 58.481, p < 0.05)

ABSTRACT The immune response is critical in cultured shrimp facing pathogens that are serious concerns. Therefore, immune-related gene expression was investigated in Penaeus vannamei fed with Aloe vera. Shrimp weighing 2.9 ± 0.8 g were fed with 1 g of A. vera kg feed−1. Six shrimp were sampled at 0, 6, 12, 24, 48, and 72 h for gene expression. Samples of time zero were taken just before feeding with aloe. After feeding with aloe during 24 h, uneaten food and waste material were removed and then shrimp were fed only with commercial feed. Quantitative real-time PCR measured time series expression of four genes (translationally controlled tumor protein [TCTP], superoxide dismutase [SOD], heat shock protein 70 [HSP70], and penaeidin4). The expression of TCTP was down-regulated, and the expression of SOD, HSP70, and penaeidin4 was up-regulated. This is the first report showing the effect of A. vera on the modulation of shrimp immune response. The immunostimulant properties of A. vera could be useful for cultured shrimp health.

ABSTRACT The effects of reducing feeding rate and molasses on water quality, growth, and gene expression of Litopenaeus vannamei were evaluated in a super intensive system with zero water exchange. A bioassay of 35 days (0,75 ± 0,22 g, 36 shrimp tank-1, 450 shrimp m-3) with treatments in triplicate was performed: I) 100% commercial feed (control group) with water exchange; II) 100% commercial feed without water exchange; III) 100% commercial feed + Bacillus licheniformis BCR 4-3 + molasses without water exchange; IV) 90% commercial feed + B. licheniformis BCR 4-3 + molasses without water exchange, and V) 80% commercial feed + B. licheniformis BCR 4-3 + molasses without water exchange. Shrimp survival, weight, nitrogenous wastes, settleable solids (SS), and the relative expression (RT-qPCR) of stress and digestive genes were determined. Shrimp survival was 100% in all treatments. The reduced diet, bioflocs, and bacilli did not affect shrimp growth. The culture conditions reduced nitrogenous wastes and modulated mRNA expression of trypsin, chymotrypsin, and heat shock protein 70. Reduced feed ration can help to maintain water quality and lower costs in intensive shrimp cultures with bioflocs.

Vibrio parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (AHPND), was isolated from the hepatopancreas of moribund whiteleg shrimp of commercial farms from Guasave, Sinaloa, Mexico. The isolates were screened on thiosulfate citrate bile salt sucrose agar plates for the selection of green colonies and further characterized through PCR with AP3 primers, 89F/R primers, hemolysin genes, hemolytic and enzymatic activity, hydrophobicity, autoaggregation, and biofilm formation. Bioassays by immersion challenge were conducted to confirm the pathogenicity of selected bacterial strains. In addition, the LC50 was calculated for each isolate. All isolates (35) belonged to V. parahaemolyticus, but three isolates did not correspond to strains that cause AHPND since they were negative with 89F/R primers. All isolates were a-hemolytic and showed biofilm formation (from moderate to strong). Isolates were hydrophobic or hydrophilic and showed high autoaggregation capacity. Eight strains did not kill shrimp and eleven were pathogenic, but differences in virulence were found among them perhaps due to α-hemolysis and differences in biofilm formation and hydrophobicity. Therefore, performed characterization may help to understand the pathogenicity of V. parahaemolyticus. Finally, results showed that smaller shrimp are less resistant to V. parahaemolyticus infection.

Vibrio parahaemolyticus, el agente causante de la enfermedad de la necrosis hepatopancreática aguda (AHPND), fue aislado del hepatopáncreas de camarón blanco moribundo proveniente de granjas comerciales de Guasave, Sinaloa, México. Los aislados (colonias verdes) fueron seleccionados en placas de agar TCBS, purificados y caracterizados mediante PCR con oligos AP3, 89F/R y genes de hemolisinas, actividad hemolítica y enzimática, hidrofobicidad, autoagregación y la formación de biopelículas. Se realizaron infecciones experimentales por inmersión para confirmar la patogenicidad de los aislados bacterianos seleccionados. Además, se calculó la LC50 para cada aislado. Todos los aislados (35) pertenecen a V. parahaemolyticus, pero tres de ellos no corresponden a las cepas que causan AHPND ya que fueron negativos con los oligos 89F/R. Todos los aislados fueron a-hemolíticos y formaron biopelículas (de moderado a fuerte). Los aislados fueron hidrofóbicos o hidrofílicos y mostraron gran capacidad de autoagregación. Ocho aislados no mataron a los camarones pero once fueron patógenos, aunque se encontraron diferencias en la virulencia entre ellos. Por lo tanto, la caracterización realizada puede ayudar a entender la patogenicidad de V. parahaemolyticus. Finalmente, los resultados mostraron que los camarones más pequeños son menos resistentes a la infección por V. parahaemolyticus.

The effect of inulin and fulvic acid, added in the feed, on growth, survival, WSSV prevalence, and immune system was studied in Litopenaeus vannamei. To the above, a bioassay, with treatments in triplicate, was performed to test different additive concentrations. WSSV analysis was done in organisms infected with a relatively high viral load using single and nested PCR. At the end of the bioassay, hemolymph was extracted and the immune system was studied in hemocytes at biochemical and genetic level (quantitative PCR). The final growth was similar in all treatments and survival was between 66,7% and 93,3%. WSSV prevalence decreased 13% as compared to control. The number of hemocytes, phenoloxidase activity, and superoxide anion concentration were similar in all treatments. Inulin and fulvic acid modulated the expression of transglutaminase, superoxide dismutase, and prophenoloxidase genes, but not the Toll receptor. Additives do not negatively affect growth of white shrimp and they protect them against WSSV when infected with a relatively high viral load. Additives did not affect the immune system effectors studied at biochemical level but they modulated the expression of some immune-related genes in L. vannamei.

Se estudió el efecto del prebiótico inulina y ácido fúlvico, adicionados en el alimento, sobre el crecimiento, supervivencia, prevalencia de WSSV y sistema inmune de Litopenaeus vannamei. Para esto, se realizó un bioensayo, con tratamientos por triplicado, donde se probaron diferentes concentraciones de los aditivos. Se hizo un análisis de WSSV en organismos infectados con una carga viral relativamente alta utilizando la PCR sencilla y anidada. Al final del bioensayo se extrajo la hemolinfa y se estudió el sistema inmune en hemocitos a nivel bioquímico y genético (PCR cuantitativo). El peso final fue similar en todos los tratamientos y la supervivencia estuvo entre 66,7% y 93,3%. La prevalencia de WSSV disminuyó un 13% respecto al control. El número de hemocitos, la actividad de la fenoloxidasa y la concentración de anión superóxido fueron similares en todos los tratamientos. Los aditivos modularon la expresión de los genes transglutaminasa, superóxido dismutasa y profenoloxidasa, pero no la del receptor Toll. Los aditivos no afectan negativamente el crecimiento y protegen al camarón contra WSSV en organismos infectados con una carga viral relativamente alta. No se observó efecto de los aditivos en los efectores del sistema inmune estudiados a nivel bioquímico pero si modularon la expresión de algunos genes relacionados con el sistema inmune en L. vannamei.

A 26-day bioassay was performed to evaluate the immunostimulating effect of lactic acid bacteria and yeasts (IM), added in the feed, in Litopenaeus vannamei. Bioassay treatments were performed in triplicate: I) control diet (Camaronina®); II) IM in food, daily; III) IM in food every three days and; IV) IM in food every six days. The shrimp were WSSV-free. To study the immune system, a total count of hemocytes, the concentration of superoxide anion, and the phenoloxidase activity were analyzed. We also studied the semiquantitative expression of six immune system genes, using the technique of RT-PCR. There was no significant increase in the growth and survival, the total count of hemocytes, the protein concentration, and the concentration of superoxide anion. Phenoloxidase activity in plasma in the treatment IV was significantly higher than in treatments I, II, and III. The phenoloxidase of HLS (proPO) in the IV treatment was significantly higher than in treatments I and III. The IM caused a significant overexpression of the genes coding for the prophenoloxidase (treatment IV), lysozyme (treatment III), and transglutaminase (treatment II) relative to the untreated animals (control). The mixture of microbial immunostimulants may increase the resistance of cultured L. vannamei against pathogens.

Se realizó un bioensayo de 26 días para evaluar el efecto inmunoestimulante de bacterias ácido lácticas y levaduras (MI), adicionadas en el alimento, en Litopenaeus vannamei. Los tratamientos del bioensayo se realizaron por triplicado: I) dieta control (Camaronina®); II) MI en alimento, diario; III) MI en alimento, cada tres días y; IV) MI en alimento, cada seis días. Los camarones sólo eran libres de WSSV. Para el estudio del sistema inmune se hizo un conteo total de hemocitos, se determinó bioquímicamente la concentración de anión superóxido, y la actividad de la fenoloxidasa. También se estudió la expresión semicuantitativa de seis genes del sistema inmune, utilizando la técnica de RT-PCR. No hubo aumento significativo en el crecimiento y la supervivencia, el conteo total de hemocitos, la concentración de la proteína total en plasma y hemocitos, y la concentración del anión superóxido. La actividad de la fenoloxidasa en plasma en el tratamiento IV fue significativamente mayor que en los tratamientos I, II y III. La fenoloxidasa del SLH (proFO) en el tratamiento IV fue significativamente mayor que en los tratamientos I y III. La MI provocó una sobreexpresión significativa de los genes que codifican para la profenoloxidasa (tratamiento IV), lisozima (tratamiento III) y transglutaminasa (tratamiento II), con respecto a los animales no tratados (control). La mezcla de inmunoestimulantes microbianos puede aumentar la resistencia de L. vannamei contra patógenos en los cultivos.

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 caracterizo: 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 duro 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) 2×10(5)UFC/camarón; (3) 4×10(5)UFC/camarón; (4) 2×10(6)UFC/camarón; (5) 4×10(6)UFC/camarón y (6) 8×10(6)UFC/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 1.178×10(5)UFC/g de peso corporal. Los resultados permiten establecer que las cepas de V. sinaloensis pueden actuar como patógenos oportunistas en L. vannamei cultivado.

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) 2×10(5)CFU/shrimp; (3) 4×10(5)CFU/shrimp; (4) 2×10(6)CFU/shrimp; (5) 4×10(6)CFU/shrimp, and (6) 8×10(6)CFU/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 1.178×10(5)CFU/g body weight. V. sinaloensis may act as opportunistic pathogens for cultured L. vannamei. Rev. Biol. Trop. 60 (2): 567-576. Epub 2012 June 01.