Partial characterization of digestive proteases in juveniles of Microphis brachyurus (short-tailed pipefish) (Syngnathiformes: Syngnathidae)

Short-tailed pipe fish (Microphis brachyurus) is a freshwater organism with high economic potential for the aquarium hobby, so it is necessary to implement methods to promote its culture through studies of digestive physiology. General activities of acid and alkaline proteases were evaluated, as well as the effect of pH, temperature and inhibitors. The optimal pH of stomach proteases was 2, while the optimal pH of intestinal proteases was 10. Optimal temperature for the acidic proteases was 35 ºC, while for alkaline proteases it was 45 ºC. Thermal stability showed high resistance at 35 ºC for both acid and alkaline proteases (above 100% residual activity). Acid proteases are resistant at pH 2 (50% of residual activity), meanwhile alkaline proteases were highly resistant at pH 10 (90% of residual activity). Acid proteases were inhibited by 80% with pepstatin A and alkaline proteases were inhibited with TLCK and TPCK for trypsin (75%) and chymotrypsin (80%), respectively. Finally, metallo-proteases were 75% partially inhibited some serine proteases by 75% with EDTA. In conclusion, M. brachyurus has a good digestive capacity, since they can degrade a wide variety of proteins due to their greater proteolytic activity.(AU)

El pez pipa (Microphis brachyurus) es un organismo dulceacuícola con alto potencial económico para la acuarofilia; sin embargo, es necesario implementar su cultivo a través de estudios de fisiología digestiva. Se evaluó el efecto del pH, temperatura e inhibidores sobre las actividades enzimáticas de proteasas ácidas y alcalinas. El pH óptimo de proteasas estomacales es de 2, mientras que el de proteases intestinales es de 10. La temperatura óptima de proteasas ácidas es de 35 ºC y las alcalinas de 45 ºC. La estabilidad térmica para proteasas ácidas y alcalinas es a los 35 ºC (más de 100% de actividad residual). La estabilidad a los diferentes pH de las proteasas ácidas es en 2 (50 % de la actividad residual), mientras que para las proteasas alcalinas es en 10 (90 % de la actividad residual). Las proteasas ácidas fueron inhibidas en 80% con pepstatina A y las proteasas alcalinas fueron altamente inhibidas con TLCK para tripsina (75%) y TPCK quimitripsina (80%). Finalmente, las metaloproteasas fueron inactivadas con EDTA en 70%. En conclusión, M. brachyurus tiene una buena capacidad digestiva al degradar una amplia variedad de proteinas debido a su alta actividad proteolítica.(AU)

The sagittal otolith morphology observations of sturgeon species in Iranian waters of the Caspian Sea / Observaciones sobre la morfologia de otolitos sagitales de varias especies de esturion en las aguas iranies del Mar Caspio

The morphology of the sagittal otolith of Great sturgeon (Huso huso), Persian sturgeon (Acipenser persicus) and starry sturgeon (Acipenser stellatus) species from the Iranian waters of the Caspian Sea were studied. Three otolith measurements and three shape indices were recorded from 90 sturgeon specimens. Fish biometry traits were measured and relationship between sagittal otolith length (OL)-total length (TL), and sagittal otolith weight (WO)-body weight of fish (BW) were estimated. Sagittal otolith has a triangle shape with irregular edges in great sturgeon, elongate triangle with smooth surfaces in Persian sturgeon, and relatively circular with smooth surface in starry sturgeon. The ratio of the WO/BW in starry sturgeon was significantly higher ( P <0.05) than great sturgeon and Persian sturgeon. There is a direct proportional relationship between BW and WO in Persian sturgeon (r2=0.7), great sturgeon (r2=0.9) and starry sturgeon (r2=0.9). Regression line slope for these relationships in starry sturgeon were less than Persian sturgeon and great sturgeon. Furtheremore, there is significant linear regression between OL-TL. Results showed that it is possible to identify Caspian sturgeon species based on body morphometry and sagittal otolith characteristics.

Se estudió la morfología del otolito sagital del gran esturión (Huso huso), el esturión persa (Acipenser persicus) y el esturión estrellado (Acipenser stellatus) de las aguas iraníes del Mar Caspio. Se registraron tres mediciones de otolitos y tres índices de forma, de 90 especímenes de esturión. Se midieron los rasgos de la biometría de los peces y se estimó la relación entre la longitud del otolito sagital (LO) - longitud total (LT) y el peso del otolito (PO) - peso del cuerpo de los peces (PC). El otolito sagital tiene forma de triángulo con márgenes irregulares en el gran estu- rión (Huso huso), triángulo alargado con superficies lisas en estu- rión persa y relativamente circular con superficie lisa en esturión estrellado. La relación del PO / PC en el esturión estrellado fue significativamente mayor (P <0.05) que el gran esturión y el estu- rión persa. Existe una relación directamente proporcional entre PC y PO en el esturión persa (r2 = 0.7), el gran esturión (r2 = 0.9) y el esturión estrellado (r2 = 0.9). La pendiente de la línea de regresión para estas relaciones en el esturión estrellado fue menor que el esturión persa y el gran esturión. Por otra parte, existe una regresión lineal significativa entre LO-LT. Los resultados mostraron que es posible identificar especies de esturión del Caspio basadas en la morfometría corporal y las características del otolito sagital.

The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae) to physical and chemical stress / Efecto de la astaxantina en la resistencia al estrés físico y químico de los langostinos jóvenes de Macrobrachium nipponense (Decapoda: Palaemonidae)

In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquacultureand its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of differentphysicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50mg/kg, AX100 with 100mg/kg, and AX150 with 150mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1 000L) used for holding prawns. Three replicate aquaria were initially stocked with 36org/m² per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5mg/L; and ammonia-nitrogen, 0.05mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75mg/L), and reduced oxygen (0.5mg/L). The time to lethargyand the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed greater reduction than those exposed to other treatments. It is possible that higher levels of astaxanthin in the body under oxygen reduction stress can be beneficial forprawns. These results suggest that male prawns showed lethargy earlier than females, and the percentage of carotenoid reduction in muscle and gill tissues was higher inmales. Rev. Biol. Trop. 62 (4): 1331-1341. Epub 2014 December 01.

En años recientes, la utilización de nuevas técnicas científicas ha tenido un efecto importante en mejorar los procesos de producción en acuicultura. La astaxantina tiene varias propiedades en la acuicultura y sus propiedades antioxidantes se encuentran estrechamente relacionadas con la resistencia al estrés. La astaxantina en muchos crustáceos y peces es un factor esencial para el crecimiento. El objetivo de este estudio fue evaluar la resistencia del langostino (Macrobrachium nipponense) alimentado con dietas conteniendo diferentes cantidades de astaxantina (AX), bajo diferentes condiciones de estrés ambiental. Un ensayo de 70 días fue llevado a cabo para evaluar el efecto de la suplementación de fuentes de astaxantina (Carophyll Pink, 10 % astaxanthin) en varios niveles en la dieta de jóvenes de M. nipponense. Cuatro dietas fueron preparadas: AX0 sin astaxantina, AX50 con 50mg/kg, AX100 con 100mg/kg y AX150 con 150mg/kg de astaxantina. Los ensayos de alimentación fueron conducidos en un sistema de recirculación de agua consistente en 12 estanques de fibra de vidrio (1 000L). Tres replicas fueron sembradas con 36org/m2 por tanque. Durante el experimento los langostinos fueron mantenidos con un fotoperiodo de 12:12 luz:oscuridad con lámparas incandescentes y los parámetros de la calidad del agua fueron mantenidos a 25-26°C la temperatura, 1 g/L la salinidad, 8.5-8.8 el pH, 6.0-6.5 mg/L el oxígeno y 0.05mg/L el nitrógeno amoniacal. La incorporación de la astaxantina, producción y condiciones fisicoquímicas fueron registradas después de 10 semanas de alimentación. Al final del periodo de crecimiento, los langostinos fueron expuestos a un shock térmico (0°C), amonio (0.75mg/L) y reducción de oxígeno 0.5 mg/L. El tiempo de letargia y el tiempo de muerte fueron registrados. Se encontró que la dieta con la mayor concentración de astaxantina (150mg/kg) presentó el mayor tiempo de letargia y la mayor concentración en branquias y músculo en el langostino M. nipponense.

Effects of different dietary of protein and lipid levels on the growth of freshwater prawns (Macrobrachium carcinus) broodstock / Efecto de diferentes niveles dietéticos de proteína y lípidos en el crecimiento de reproductores del langostino de agua dulce (Macrobrachium carcinus)

Objective. Evaluate the effects of varying dietary protein and lipid levels on the growth and body composition of adult freshwater prawns, Macrobrachium carcinus (Linnaeus 1758), in a recirculation system for 11 weeks (77 days). Materials and methods. The experimental treatments were assigned in triplicate. Six test diets were formulated with three different protein levels (35, 40 and 45%) and two lipid levels (8 and 13%). Results. The highest survival rate, growth indices and feed utilization were observed for M. carcinus adults fed protein:lipid diets of 35:13, 40:13 and 45:13, and the lowest values for these parameters were recorded for prawns fed diets with the lowest lipid levels; the differences in these parameters between these types of diets were significant (p<0.05). A non-significant tendency for an increased percentage of protein in the body with an increased dietary protein level was observed. The percentage of lipids decreased with an increasing dietary protein level, and no definite trends in ash content were found. Conclusions. The results suggest that a diet with 35% dietary crude protein and 13% lipids enhances the growth and body composition of adult M. carcinus.

Objetivo. Evaluar los efectos de diversos niveles dietéticos de proteína y lípidos en el crecimiento y composición corporal de reproductores del langostino de agua dulce Macrobrachium carcinus (Linnaeus 1758), en un sistema de recirculación durante 11 semanas (77 días). Materiales y métodos. Los tratamientos experimentales fueron asignados por triplicado. Seis dietas de prueba fueron formuladas con tres niveles diferentes de proteínas (35, 40 y 45%) y dos niveles de lípidos (8 y 13%). Resultados. Se observó la tasa más alta de supervivencia, índices de crecimiento y utilización del alimento para ejemplares adultos de M. carcinus alimentados con niveles dietarios de proteína: lípidos de 35:13, 40:13 y 45:13, mientras que el valor más bajo en estos parámetros se registró en langostinos alimentados con el nivel más bajo de lípidos; las diferencias en estos parámetros entre estos tipos de dietas fueron significativas (p<0.05). Se observó una tendencia no significativa en un aumento del porcentaje de proteína en el cuerpo con un nivel mayor de proteína dietética. El porcentaje de lípidos disminuyó con un nivel de proteína dietario creciente, y no se encontró ninguna tendencia definida en el contenido de cenizas. Conclusiones. Los resultados sugieren que una combinación de dieta de proteína cruda del 35% y 13% de lípidos mejora el crecimiento y composición corporal de M. carcinus adultos.

Reproductive performance of the Mesa silverside (Chirostoma jordani Woolman, 1894) under natural and controlled photoperiods

Chirostoma jordani is a native annual species inhabiting lacustrine waters of the Central Mexico Plateau. It is widely distributed and is currently facing high environmental pressures. Five experiments were performed to study the reproductive performance of this species. Four of the experiments were conducted in 270-L indoor recirculation tanks. Two males and one female at the first stage of reproduction were included in each test. A photoperiod of 14 light hours and 10 dark hours was used. In a fifth experiment, 10 females and 15 males were kept in an outdoor 3,000-L recirculation tank under natural photoperiod. The number of spawns, fertilised eggs and 30-day-old juveniles were counted and the survival rate was calculated. The results indicated significant differences (P< 0.05) between treatments. Higher spawn numbers and greater egg production were observed under controlled photoperiod, and higher numbers of juveniles and a higher survival rate were observed under natural photoperiod. The trials exhibited different patterns of egg production during the experiment. The egg production in the natural-photoperiod trials followed a polynomial curve model. In contrast, the trials under the controlled photoperiod showed an irregular pattern of increases and decreases in egg production.

Growth of fresh-water prawn Macrobrachium tenellum (Smith, 1871) juveniles fed isoproteic diets substituting fish meal by soya bean meal

Growth parameters (standard length, weight, specific growth rate and daily weight gain) of prawn Macrobrachium tenellum juveniles fed 40 percent crude protein isoproteic diets substituting fish meal with soya bean meal at various levels (20, 40, 60, 80 and 100 percent) were evaluated for 45 days under laboratory conditions. Experimental diets were compared with a 100 percent fish meal based diet. Total survival was recorded for all the treatments at the end of the experiment. There were no significant differences (p > 0.05) for all the growth parameters among the dietary treatments. The initial mean weight (0.36 ± 0.10 g) increased almost three times (1.00 ± 0.13 g) after 45 days. The final specific growth fluctuated from 1.82 percent BW/d for the 60 percent soya bean meal inclusion diet, to 2.62 percent for the 100 percent fish meal diet. The mean final survival was 91.66 percent. Growth performance of M. tenellum juveniles was not affected by the dietary soya bean meal levels tested.

Os parâmetros do crescimento (comprimento padrão, peso, taxa de crescimento específica e ganho diário do peso) de juveniles do Macrobrachium tenellum alimentaram a 40 por cento a proteína crua as dietas isoproteic que substituem a refeição de peixes com feijão de soya a refeição nos vários níveis (20, 40, 60, 80 e 100 por cento) foi avaliada por 45 dias sob condições do laboratório. As dietas experimentais foram comparadas com uma dieta baseada da refeição de peixes de 100 por cento. A sobrevivência total foi gravada para todos os tratamentos no fim da experiência. Não havia nenhuma diferença significativa (p > 0.05) para todos os parâmetros do crescimento entre os tratamentos dietéticos. O peso médio inicial (0.36 ± 0.10 g) aumentado quase três vezes (1.00 ± 0.13 g) após 45 dias da cultura. O crescimento específico final flutuou de 1.82 por cento BW/d para a dieta do inclusion da refeição do feijão de soya de 60 por cento, a 2.62 por cento obtidos para a dieta da refeição de peixes de 100 por cento. A sobrevivência final média foi de 91.66 por cento. O desempenho do crescimento de juveniles do M. tenellum não foi afetado pelos níveis dietéticos da refeição do feijão de soya testados.

Bioensayo de pigmentación de trucha arcoiris (Oncorhynchus mykiis) con extractos de chile ancho (Capsicum annuum) / Rainbow trout (Oncorhynchus mykiis) pigmentation bioassay using chili (Capsicum annuum) extracts

En el cultivo de trucha se requiere de una dieta iniciadora que contenga pigmentos como la astaxantina y la cantaxantina para proporcionar el color rosado característico de las truchas silvestres. La producción de pigmentos sintéticos no alcanza a satisfacer los requerimientos del mercado acuícola, además de tener un precio alto de venta. Por lo anterior, en el presente estudio se evaluó la acumulación de los pigmentos contenidos en los extractos de chile ancho (Capsicum annum), saponificados y esterificados, en la piel y músculo de la trucha arcoiris (Oncorhynchus mykiis). Para ello se emplearon tres tratamientos experimentales, que consistieron en la inclusión de extractos de chile saponificado, sin saponificar y de astaxantina comercial en la dieta finalizadora. En cada tratamiento se tuvieron 150 organismos con un peso promedio inicial de 150 g y dos repeticiones. Se encontró que los extractos de chile ancho, en sus dos presentaciones, pigmentaban la piel y el músculo de la trucha, sin embargo el color producido fue más claro y menos rojo que el obtenido con la dieta que incluyó astaxantina