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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. [ABSTRACT FROM AUTHOR]

The chilhuil sea catfish (Bagre panamensis) is an ecologically relevant species contributing to the structure, organization, and functioning of the ecosystems it inhabits. Also, it is an important artisanal fishery resource in the Mexican Pacific coast. This study aimed to determine the genetic diversity, population structure, and historical demography of B. panamensis in the Mexican Pacific. The mitochondrial DNA was amplified from two distinct regions, r16S and COI, resulting in an 1142bp of the concatenated genes. Low genetic diversity levels were detected for r16S (H = 12; h = 0.131; π = 0.0003) and high genetic diversity levels for COI (H = 57; h = 0.9128; π = 0.0039) and the concatenated gene fragments (H = 62; h = 0.9307; π = 0.0023). Population structure analysis indicated ‘panmixia’ for B. panamensis along the Mexican Pacific. Furthermore, historical demographic analysis (Tajima’s D, Fu’s Fs, mismatch distribution, and Bayesian Skyline plot analyses) supported a population expansion scenario for the studied species. [ABSTRACT FROM AUTHOR]

Among Bagre genera, there is a high variation in the estimation of age, a concern due to overexploitation risk in fisheries because of age underestimation. Bagre panamensis is an important fishery resource of the Mexican Pacific and the Gulf of California. Its age is known from otoliths, but its accuracy needs to be confirmed, and the periodicity of the otoliths record validated. The external morphology, some microstructure attributes, and age record of B. panamensis' otoliths were described from 371 specimens collected southeast of the Gulf of California. The lapilli otoliths were larger than the sagittae and asterisci otoliths. The lapilli otoliths present aragonite crystals with a prismatic shape, and their growth is radial, from the core to the otolith edge. The lapilli otoliths form an annual growth ring, defined by the slowdown in the growth that occurs during April to July, during the breeding season. The ages of the individuals ranged from 1 to 15 years, and the applied method is considered adequate and accurate for its estimation (otolith cross-sectioning and red-neutral staining). [ABSTRACT FROM AUTHOR]

The recovery of proteases from fish viscera could be a strategy to reduce environmental problems caused by inadequate disposal of fish by-products. This study reports the biochemical characterization of proteases isolated from chihuil sea catfish (Bagre panamensis) intestines and the evaluation of their stability to different physical and chemical factors. Protein hydrolysates from chihuil muscle and casein were produced using its semi-purified proteases extract (SPE) and alcalase. Assays with specific protease inhibitors indicate that trypsin and chymotrypsin are the main types of serine proteases in SPE. Semi-purified enzymes exhibited proteolytic activity at alkaline pH (9–12), and high stability at low/mild temperatures (10–40 °C). A 92% of SPE proteolytic activity was retained in the presence of 30% NaCl. The enzyme extract was stable in reducing agents (2-mercaptoethanol and DTT) but lost about 70% of proteolytic activity in anionic detergents like SDS and tween-80. Organic solvents did not affect the enzyme activity of SPE. Finally, maintaining a same E/S ratio for protein hydrolysates elaboration, chihuil serin proteases exhibited a higher hydrolytic efficiency compared to alcalase when casein and proteins from chihuil muscle were hydrolyzed. Thus, the semi-purification of serine proteases from chihuil viscera provided a low-cost source of enzymes with interesting catalytic features. [ABSTRACT FROM AUTHOR]

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The chihuil sea catfish (Bagre panamensis) is endemic of the Eastern Pacific and is a species of fishery importance in the Mexican Pacific. The complete mitochondrial genome of Bagre panamensis has been assembled from Illumina sequencing data. The circular genome was 16,714 bp in lengh, and consist of 13 protein-coding, two ribosomal RNAs (rRNAs), and 22 transfer RNA (tRNA) genes. Base composition is 30.8% A, 26.6% T, 28.2% C, and 14.4% G, and 42.6% GC content. Protein-coding genes present two start codon (ATG and GTG) and eight stop codon (TAA, TCT, CCT, TTA, CAT, AAT, ATT, and TAG). The control region possesses the highest A + T (64.4%) and lowest G + C content (35.6%) among all mitochondrial regions. These data would contribute to the evolutionary studies of related taxa.

The chihuil sea catfish (Bagre panamensis) is endemic of the Eastern Pacific and is a species of fishery importance in the Mexican Pacific. The complete mitochondrial genome of Bagre panamensis has been assembled from Illumina sequencing data. The circular genome was 16,714 bp in lengh, and consist of 13 protein-coding, two ribosomal RNAs (rRNAs), and 22 transfer RNA (tRNA) genes. Base composition is 30.8% A, 26.6% T, 28.2% C, and 14.4% G, and 42.6% GC content. Protein-coding genes present two start codon (ATG and GTG) and eight stop codon (TAA, TCT, CCT, TTA, CAT, AAT, ATT, and TAG). The control region possesses the highest A + T (64.4%) and lowest G + C content (35.6%) among all mitochondrial regions. These data would contribute to the evolutionary studies of related taxa. [ABSTRACT FROM AUTHOR]

Arius manillensis is a Philippine endemic species and is an economically important fishery resource in Laguna de Bay, the largest lake in the country. Drastic reduction in population sizes of A. manillensis has been recorded in the past, which may have resulted in genetic bottleneck. In this study, the genetic diversity and population structure of A. manillensis in Laguna de Bay were assessed using the mitochondrial DNA control region. Specimens were obtained from three localities along Laguna de Bay, namely Binangonan ( n == 27), Tanay ( n == 29), and Calamba ( n == 30). Of the 86 DNA sequences generated, 22 distinct haplotypes were observed. There were four unique haplotypes for Binangonan, six for Calamba, and five for Tanay. There were two haplotypes common to the three sites. The maximum likelihood tree and median-joining network showed little geographic separation among the haplotypes. Chi-square test showed no significant differentiation in A. manillensis from the three sites. The overall computed FST was 0.0144, indicating small genetic differentiation in A. manillensis from the three localities sampled. Likewise, analysis of molecular variance showed a greater percentage of variation within population (98.62%) than variation among populations (1.38%; P == 0.21). Total haplotype diversity and nucleotide diversity among the specimens from the three sites were 0.775 and 0.013, respectively. The high haplotype diversity coupled with low nucleotide diversity observed in this study confirms that genetic bottleneck occurred in A. manillensis which was followed by population expansion. This is also supported by the non-significant values for both Tajima's D and Fu's F. Furthermore, multimodal mismatch distribution plots were generated, which is consistent with the model of spatial range expansion followed by demographic expansion. [ABSTRACT FROM AUTHOR]

By combining anion-exchange membrane purification with high-performance size-exclusion chromatography (HPSEC) analysis, a two-step chromatographic method was developed for the determination of vitellogenin (Vtg) in fish plasma. Most plasma protein interferences can be removed during anion-exchange membrane purification process. Vtg is eluted from the size-exclusion chromatography column with a retention time of about 9 min and is characterized based on the native molecular weight, with a limit of quantification of 20 μg Vtg mL-1 plasma. The spiked recovery and interassay variability were better than 80% and 4.8%. This method was successfully applied to analyze the plasma Vtg levels of loach (Misgurnus angaillicaudatus) and sea catfish (Enchelyopus elongatus). In addition to all the female fish, Vtg is detected in 75% of male loaches and 100% of male sea catfish. The result indicates that some chemicals or unknown factors with estrogenic activity have induced male fish to produce Vtg. [ABSTRACT FROM AUTHOR]