Total mercury and selenium levels in commercial shrimp along the Pacific coast of Mexico.

The present study analyzed the content of total mercury (THg) and selenium (Se) in the muscle of shrimp collected from local markets in the 11 Pacific coastal states of Mexico. Methylmercury (MeHg) concentration, Se:Hg ratio, health benefits value from selenium consumption (HBVSe) and the permissible weekly consumption were estimated to assess the health risk to consumers. All THg and Se concentrations were below the maximum permissible limits. All hazard quotient (HQ) values were <1, however in Hermosillo, Culiacán and Guadalajara, the Se:Hg ratio and HBVSe were <1 and negative, due to the low concentrations of Se. As a general conclusion, there is no risk nor benefit from the consumption of shrimp from the Pacific coast of Mexico due to its Hg and Se content.

Total Mercury and Selenium in wild Shrimp from Coastal Lagoons of Northwest Mexico: Human Health risk Assessment.

This study analyzed total mercury (THg), and selenium (Se) in edible tissues of white shrimp (Litopenaeus vannamei), blue shrimp (L. stylirostris) and brown shrimp (F. californiensis), from three states of the Northwest of Mexico in September and October 2017. Concentrations of THg and Se in the muscle were between 0.026 and 0.829 and 0.126-1.741 µg/g dry weight (dw), respectively. Significant differences were observed among Hg concentration of Sonora and Nayarit and among Se concentration of Sinaloa and Nayarit. In addition, the health risk assessment (HQ) in the three species of shrimp was between 0.550 and 0.607. All Se:Hg molar ratios were > 1 and positive HBVSe values that showed that shrimp from Northwest of Mexico does not represent a risk to human health.

First Molecular Characterization of Colletotrichum sp. and Fusarium sp. Isolated from Mangrove in Mexico and the Antagonist Effect of Trichoderma harzianum as an Effective Biocontrol Agent.

The aim of this study was to characterize potential fungal species affecting mangrove species in Mexico. The phytopathogens were identified based on morphological and molecular characteristics using internal transcribed spacer (ITS1/ITS4) primers then sequenced and compared with the other related sequences in GenBank (NCBI). Three fungal species were identified as Colletotrichum queenslandicum (Weir and Johnst, 2012) from black mangrove (Avicennia germinans); Colletotrichum ti (Weir and Johnst, 2012) from white mangrove (Laguncularia racemosa) and buttonwood mangrove (Conocarpus erectus); Fusarium equiseti (Corda) from red mangrove (Rhizophora mangle). In addition, C. ti and F. equiseti were identified from mango Mangifera indica L. sampled close by the mangrove area. This study provides first evidence of anthracnose on four mangrove species caused by Colletotrichum and Fusarium species in the "Términos" coastal lagoon in Campeche State southern Mexico. This is the first time that C. queenslandicum and C. ti are reported in Mexico. F. equiseti has not been reported affecting M. indica and R. mangle until the present work. Little is known regarding fungal diseases affecting mangroves in Mexico. These ecosystems are protected by Mexican laws and may be threatened by these pathogenic fungus. This is the first report of the effect of Trichoderma harzianum TRICHO-SIN as an effective biological control against of Colletotrichum and Fusarium species.

Effects of a co-culture of marine algae and shrimp (Litopenaeus vannamei) on the growth, survival and immune response of shrimp infected with Vibrio parahaemolyticus and white spot virus (WSSV).

In aquaculture, fighting infectious diseases is a necessity. This study measured the immuno-stimulating effect of live macroalgae consumption on Litopenaeus vannamei against Vibrio parahaemolyticus and WSSV infection in two independent bioassays. Shrimps and macroalgae were cultivated in a co-culture with two species of macroalgae separately (Gracilaria vermiculophylla and Dictyota dichotoma), and later, shrimp were infected with V. parahaemolyticus. In another bioassay, shrimp and macroalgae (G. vermiculophylla, D. dichotoma and Ulva lactuca) were grown and subsequently infected with WSSV. For both bioassays, survival after 120 h was determined, the total hemocyte count (TCH) was measured and the activity of superoxide dismutase (SOD) and catalase (CAT) in tissue were measured. The results indicate that the use of macroalgae in co-culture with L. vannamei provides a nutritional benefit that achieves higher growth than the control organisms, as well as improvements of the ammonium concentration and immune response after infection with V. parahaemolyticus and WSSV. A better immune response was obtained in organisms cultured with macroalgae in both bioassays at a ratio of 1.6-1.9 for organisms infected with bacteria and 1.4 to 1.6 times for organisms infected with the virus. In turn, the enzymatic activity of SOD and CAT were higher in the treated organisms relative to the controls in both experiments.

Effect of temperature and salinity on larval survival and development of Litopenaeus vannamei / Efecto de temperatura y salinidad sobre la supervivencia y desarrollo larval de Litopenaeus vannamei

ABSTRACT Objective. The combined effect of salinity (25, 30, 35, and 40psu) and temperature (25, 30, and 35oC) was evaluated on survival and development from nauplii V (NV) larvae until postlarvae (PL1) of Litopenaeus vannamei. Materials and methods. Four replicates were applied to each combination of salinity and temperature. The larvae were placed in 12 L beakers a density of 100larvae/L. Salinity was increased dissolving commercial salt without iodine, into marine water, whereas fresh filtered tap water was used to decrease the salinity from seawater. The NV were adapted at 35psu and 30°C during 30 minutes. Thereafter, were transferred at each experimental combination of salinity and temperature. Every 24 h, samples of larvae were obtained to determine in vivo their stage of development and survival. All data were analyzed using a two-way ANOVA. Results. Survival and larval development were significantly (p<0.05) affected by salinity, temperature and interaction of both factors. Maximum ultimate survival to PL1 was obtained at 30°C and 30psu (82.2%) followed by 30 and 35°C at 25psu (71.5 y 71.6%). The highest development at PL1 was found at 30°C and 30psu (6.76). Larval development during experiment was lower at 25°C as compared to 30 and 35°C, regardless of the salinity levels. Conclusions. The most adequate conditions for survival and larval development were obtained between 30-35°C and 25-30psu.

RESUMEN Objetivo. Analizar el efecto combinado de salinidad (25, 30, 35 y 40 ups) y temperatura (25, 30 y 35°C) sobre la supervivencia y el desarrollo de larvas nauplio V (NV) hasta postlarvas (PL1) de Litopenaeus vannamei. Materiales y métodos. Los experimentos se realizaron por cuadriplicado por cada combinación de salinidad y temperatura. Las larvas se mantuvieron en acuarios de 12 L a una densidad de 100larvas/L. La salinidad se incrementó disolviendo sal granulada libre de yodo, a partir de agua de mar, mientras que para alcanzar las salinidades menores se utilizó agua dulce filtrada. Los NV aclimatados a 35ups y 30°C durante 30 minutos fueron transferidos a cada combinación experimental de salinidad y temperatura. Cada 24 h, se obtuvieron muestras de larvas para determinar in vivo su etapa de desarrollo y supervivencia. Los datos fueron analizados por un ANOVA de dos vías. Resultados. La supervivencia y el desarrollo larval fueron significativamente afectadas por la salinidad, temperatura y su interacción (p<0.05). La máxima supervivencia final a PL1 se obtuvo a 30°C y 30ups (82.2%), seguido por 30 y 35°C a 25ups (71.5 y 71.6%). El desarrollo más alto a PL1 fue encontrado a 30°C y 30ups (6.76). El desarrollo larval durante el experimento fue más bajo a 25°C en comparación con 30 y 35°C, independientemente de los niveles de salinidad. Conclusiones. Las condiciones más adecuadas para la supervivencia y desarrollo larval se obtuvieron entre 30-35°C y 25-30ups.

Antioxidant, antimutagenic and antiproliferative activities in selected seaweed species from Sinaloa, Mexico.

Context Seaweeds from the Mexican Pacific Ocean have not been evaluated as a source of chemoprotectants. Objective The objective of this study is to evaluate chemopreventive activities of the seaweeds Phaephyceae - Padina durvillaei (Dictyotaceae) - Rodhophyceae - Spyridia filamentosa (Spyridiaceae), Gracilaria vermiculophylla (Gracilariaceae) - and Chlorophyceae - Ulva expansa (Ulvaceae), Codium isabelae (Codiaceae), Rhizoclonium riparium (Cladophoraceae) and Caulerpa sertularioides (Caulerpaceae). Materials and methods Methanol, acetone and hexane seaweed extracts were assessed at 30 and 3 mg/mL on antioxidant capacity (DPPH and ABTS assays), 0.003-3.0 mg/plate on antimutagenic activity against AFB1 using Salmonella typhimurium TA98 and TA100 tester strains in Ames test, and 12.5 to 100 µg/mL on antiproliferative activity on Murine B-cell lymphoma. Phenols, flavonoids and pigments content were also assessed as antioxidant compounds. Results Extraction yield was higher in methanol than in acetone and hexane extracts (6.4, 2.7 and 1.4% dw). Antioxidant capacity was higher in brown and green than in red seaweed species, particularly in P. durvillaei extracted in acetone (EC50 value= 16.9 and 1.56 mg/mL for DPPH and ABTS). Flavonoids and chlorophylls were identified as mainly antioxidant components; particularly in hexane extracts, which were correlated with the antioxidant capacity. Highest mutagenesis inhibition (> 40%) occurred in R. riparium at the lowest concentration assayed (0.003 mg/plate), while highest antiproliferative inhibition (37 and 72% for 12.5 and 25 µg/mL) occurred in C. sertularioides. Discussion and conclusion Flavonoids and chlorophylls explained the chemopreventive activities assessed in S. filamentosa, R. riparium and C. sertularioides. These seaweeds have a high potential as a source of novel chemoprotectants.

Effects of methanolic macroalgae extracts from Caulerpa sertularioides and Ulva lactuca on Litopenaeus vannamei survival in the presence of Vibrio bacteria.

Macroalgae are potentially excellent sources of highly bioactive secondary metabolites that are useful for the development of new functional ingredients. This study was conducted to determine whether methanolic extracts from Caulerpa sertularioides and Ulva lactuca macroalgae might be possible alternatives for the prevention of shrimp vibriosis, which is caused by Vibrio parahaemolyticus and Vibrio alginolyticus. Macroalgae extracts prepared with methanol as the solvent were evaluated for antibacterial activity with the microplate method. The extracts' effects on the mortality of juvenile Litopenaeus vannamei were evaluated at doses of 150 and 300 mg L(-1). Two independent assays for V. parahaemolyticus and V. alginolyticus were performed. The methanolic extract of C. sertularioides exhibited activity against V. parahaemolyticus and V. alginolyticus, and it had minimal inhibitory concentrations of <1000 and < 1500 µg mL(-1), respectively. L. vannamei mortality in the presence of both The methanolic extract of C. sertularioides exhibited activity against V. parahaemolyticus and V. alginolyticus, and it had minimal inhibitory concentrations of <1000 and <1500 µg mL(-1), respectively. and V. alginolyticus bacteria significantly decreased after treatment with 300 mg L(-1) C. sertularioides methanolic extract.

Effect of the diet traditional and non-traditional on the respiration and excretion in larvae of white shrimp Litopenaeus vannamei / Efecto de la dieta tradicional y no tradicional en la respiración y excreción de larvas de camarón blanco Litopenaeus vannamei

Objective. It was studied the respiration and ammoniacal excretion of zoeas and mysis of Litopenaeus vannamei fed with the diet used traditionally (of microalgae and nauplios of Artemia) and another alternative (not traditional) of microalgae with rotifers. Materials and methods. After four hours the oxygen consumption and ammonia excretion in BOD bottles with 60 larvae (closed respirometers) was estimated. The concentrations of O2 and NH4+ were measured with an electrode polarográfico in the first case and with the indophenol blue technique for the second. Results. In zoea, oxygen consumption increased with development and showed statistical differences (p=0.023). In mysis, the oxygen consumption were significance in the traditional diet, whereas no differences were alternative (p=0.003). In both stages for the ammoniacal excretion increased development stage and there were detected statistical difference (p<0.001), although to the diets were not noticed significant differences. Conclusions. A higher energy absorption for zoea (I, II y III) what mysis (I, II y III) larvae was obtained, this is likely an interaction between rates of respiration and excretion caused by variations in the efficiency of absorption by the larvae. The weights obtained in both larvae were not supplied with differences between diets.

Objetivo. Se analizó la respiración (O2) y excreción amoniacal (NH4+) en larvas zoea y mysis de camarón blanco Litopenaeus vannamei, alimentadas con las dietas tradicionales (microalgas y nauplios de Artemia) y no tradicionales (microalgas y rotíferos). Materiales y métodos. A las cuatro horas de experimentación se estimó el consumo de oxígeno y la excreción de amonio en botellas BOD con 60 larvas (respirómetros cerrados). La concentración de O2 se midió con un electrodo polarográfico y la NH4+ se determinó con la técnica de azul de Indofenol. Resultados. En zoea, el consumo de oxígeno incrementó con el desarrollo y se presentaron diferencias estadísticas (p=0.023). En mysis, los consumos de oxígeno presentaron una significancia entre la dieta tradicional, mientras en la alternativa no se obtuvieron diferencias (p=0.003). La excreción en ambos estadios larvales aumentó con la fase y se detectaron diferencias estadísticas (p<0.001), aunque no se registraron diferencias significativas en las larvas respecto a las dietas suministradas. Conclusiones. Se obtuvo una absorción de energía superior para las zoea (I, II y III) que mysis (I, II y III), esto probablemente a una interacción entre las tasas de respiración y de excreción provocada por variaciones en la eficiencia de absorción de las larvas. Los pesos obtenidos en ambas larvas no resultaron con diferencias entre las dietas suministradas.