Production of Protein Hydrolysates Using Marine Catfish Bagre panamensis Muscle or Casein as Substrates: Effect of Enzymatic Source and Degree of Hydrolysis on Antioxidant and Biochemical Properties.

Protein hydrolysates from fishery byproducts have resulted to be nutraceutical ingredients with potential to be applied in human nutrition; however, critical quality attributes are dependent on some process parameters such as enzyme source and degree of hydrolysis. This study analyzed the biochemical properties and in vitro antioxidant activity (using DPPH, ABTS, and FRAP assays), of protein hydrolysates at 10, 20, and 30% degree of hydrolysis (DH), measured by pH-STAT and prepared from sea catfish (Bagre panamensis) muscle and casein as protein sources by treatment with alcalase (ALC) and a semi-purified protease extract (SPE) from B. panamensis intestinal tissues as enzyme sources. With SPE, the DH was reached faster than ALC regardless of the protein substrate used. Sea catfish muscle (MUSC) hydrolysate made with SPE at 30% DH showed the highest antioxidant activity (DPPH: 118.8 µmoles TE/mg; ABTS: EC50 of 1.5 mg/mL). In FRAP assay, the MUSC hydrolysates produced with SPE or ALC at 20% DH showed the higher activity (0.38 and 0.40 µmoles TE/mg, respectively). MUSC hydrolysates made with SPE contained the highest proportion of peptides with MW < 1.35 kDa and had a high protein content (72 to 78%), and almost 50% of the amino acids were essential. These results suggest that intestinal proteases and muscle of marine catfish represent a potential source to elaborate antioxidant protein hydrolysates. Our results promote the full utilization of this fish species and offer a biotechnological strategy for the management and valorization of its byproducts.

Reproduction and community structure of fish from winter catch sites from industrial shrimp bycatch from the northeast and southeast Mexican Pacific.

The shrimp fishery is one of the most important fisheries in the world, although the low selectivity from trawling nets has led to the capture of a large number of non-target species. Shrimp-bycatch species include a large number of fish and invertebrate species, of which fish species are the most abundant. The present study aims to determine the community structure as well as the average sizes at first maturity of the fish species from shrimp-bycatch caught from industrial fisheries in the Mexican Pacific from Sinaloa to Guerrero, from January to March 2015. The shrimp-bycatch fish diversity value was found to be 2.22. A total of 37 species of finfish were found, of which five were considered rare. The fish species with the highest Importance Value Index (IVI) levels were Pseudupeneus grandisquamis, Paralichthys woolmani, Lutjanus peru and Diapterus peruvianus. The average size at first maturity was calculated for all species. Of the analysed organisms, 90% were in the juvenile stage, including species with riverine and artisanal fisheries. The present study demonstrates the risk within marine populations to different non-target species due to the poor selectivity of shrimp trawls.

Gonadal development of Peprilus medius (Peters, 1869) (Perciformes: Stromateidae) from Southeast of the Gulf of California, Mexico / Desarrollo gonádico de Peprilus medius (Peters, 1869) (Perciformes: Stromateidae) del Sureste del Golfo de California, México

The gonadal development assessment is a fundamental work in researching the reproduction of Peprilus medius, on the way to understand its population dynamics and to achieve a sustainable management of its fisheries. The diagnosis based on morphochromatic features is the quicker, more practical and cheaper method, and properly validated, it may be an accurate procedure. This is particularly useful in researches when it is required to provide prompt and accurate information to support decision-making for fisheries management, and during long-term fisheries monitoring to detect changes in reproductive patterns due to environmental anomalies. These are issues of concern in P. medius and other fishery resources. In this context, a scale that describes the gonadal development through morphochromatic and histological features is presented, and plus anatomical observations of the reproductive organs. Ovarian development was characterized through six phases: immature, development (sub-phases: early and late), mature, spawning (sub-phases: partial and partial post-spawning), post-spawning and resting. Testicular development was described through five phases: immature, development, ejaculation, ejaculated and resting. The position and shape of the reproductive organs are apparently defined by the shape of the fish and the visceral cavity. P. medius's gonads show a gonadal lobe at lower position and an upper lobe in the visceral cavity, and both lobes presented a horizontal placement from gonopore toward the back of the fish. In addition, gonadal deformities occurrence due to deformities in the visceral cavity was evidenced. We recommend to use presented descriptions as a guide in gonadal assessment.

La evaluación del desarrollo gonádico es una labor fundamental para investigar la reproducción de Peprilus medius, en vías a comprender la dinámica de sus poblaciones y lograr un manejo sustentable de sus pesquerías. El diagnóstico a partir de características morfocromáticas es el método más rápido, práctico y barato, y adecuadamente validado puede ser un procedimiento preciso. Este es particularmente útil en investigaciones cuando se requiere aportar información rápida y precisa que apoye la toma de decisiones de manejo pesquero, y durante los monitoreos pesqueros de largo plazo, que permiten detectar cambios en los patrones reproductivos debido a anomalías ambientales. Estos son temas preocupantes en P. medius y otros recursos pesqueros. En ese contexto se presenta una escala que describe el desarrollo gonádico a través de características morfocromáticas e histológicas, y además se presentan observaciones anatómicas de los órganos reproductores. El desarrollo ovárico fue caracterizado a través de seis fases: inmadura, desarrollo (subfases: inicial y avanzado), maduro, desove (subfases: parcial y postdesove parcial), postdesove y reposo. El desarrollo testicular fue descrito a través de cinco fases: inmadura, desarrollo, eyaculación y reposo. La posición y forma de los órganos reproductores están aparentemente definidos por la forma del pez y su cavidad visceral. Las gónadas de P. medius muestran un lóbulo gonádico en posición inferior y uno superior en la cavidad visceral, y ambos lóbulos presentan una colocación horizontal desde el gonoporo hacia la parte posterior del pez. Además se evidencia la ocurrencia de deformidades en las gónadas debido a deformidades en la cavidad visceral. Recomendamos utilizar las descripciones presentadas como una guía en la evaluación de las gónadas.

Population structure and reproductive behavior of Sinaloa cichlid Cichlasoma beani (Jordan, 1889) in a tropical reservoir

The population structure and reproductive condition of the Sinaloa cichlid Cichlasoma beani from samples obtained from June 2000 to July 2001 were determined. Samples in the first week each month from the largest trader of tilapia in the Aguamilpa Reservoir in Mexico and were caught in gillnets (9.6 and 11.4 cm stretch-mesh size). Of 596 specimens, there were 427 males and 169 females; monthly sex ratio, frequency of lengths by the multinomial distribution, timing of reproduction, condition index, and size at first maturity was determined. Differences in the sex ratio and monthly totals were significant, favoring males, except for September 2000 and March 2001. From one (August 2000) to three modal groups (July 2000 and June 2001) were identified by size. There were no significant differences in standard length weight relationships by sex, which indicated that a shared model for both genders is appropriate, and isometric growth was detected. Based on the proportion of mature and partially matures fish, the main reproductive period was April through June; size at first maturity was 18.9 cm. Water temperature was not significantly related to the percentage of mature and partially matures Sinaloa cichlids or spawning. These findings provide information for regulating the Cichlasoma beani fishery in this region such minimum legal size and non-fishing period.

Se determinó la estructura poblacional y condición reproductiva del cíclido de Sinaloa Cichlasoma beani desde junio de 2000 a julio de 2001. Las muestras se obtuvieron de la captura comercial de tilapia en el embalse de Aguamilpa, México durante la primera semana de cada mes. Los especímenes se capturaron con redes de enmalle (9,6 y 11,4 cm de tamaño de malla). De los 596 organismos recolectados, 427 fueron machos y 169 hembras. Se determinó la proporción de sexos mensual, grupos modales de tallas a través de una distribución multinomial, época reproductiva, índice de condición y talla de primera madurez. Se encontraron diferencias significativas en la proporción de sexos total y mensual favoreciendo a los machos, excepto en septiembre de 2000 y marzo de 2001. Se identificaron desde uno (agosto de 2000) hasta tres grupos modales de tallas (julio de 2000 y junio de 2001). No se encontraron diferencias significativas en la relación longitud patrón - peso total por sexo, lo que sugiere que el uso de un solo modelo para ambos sexos es adecuado, presentando crecimiento de tipo isométrico. Con base en la proporción de organismos parcialmente maduros y maduros, el pico principal de reproducción fue desde abril hasta junio; la talla de primera madurez fue de 18,9 cm. No se encontró una correlación significativa entre la temperatura del agua y el porcentaje de individuos parcialmente maduros, maduros o desovados. La información generada es útil para la regulación de la pesca de Cichlasoma beani en esta región, sugiriendo una talla mínima legal de captura y un periodo de veda adecuado para la especie.