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Yersinia ruckeri causes important economic losses for rainbow trout (Oncorhynchus mykiss) farms worldwide. This bacterial disease is likely the most common among trout in Peru; however, no commercial vaccine is available nationally, which is, in part, due to a lack of information on the bacterium. The aim of the current study was to characterize 29 Y. ruckeri isolates sampled from seven cage-reared farms in the Puno Region, the focal point for aquaculture activities in Peru. For this, samples were taken from fish with clinical signs (i.e. haemorrhages, uni- or bilateral exophthalmia, hyphaemia and/or melanosis). Notable among our findings was the existence of both Y. ruckeri biotype 1 (9 isolates) and biotype 2 (20 isolates; negative for sorbitol and Tween 80). The isolates further differed in API profiles 5307100 (21 isolates), 1307100 (4 isolates), 1305100 (2 isolates), 1307120 (1 isolate) and 5305100 (1 isolate), with the main differences being in the tests for lysine decarboxylase, gelatine hydrolysis and D-saccharose fermentation. Despite these differences, all isolates shared identical ERIC-PCR and REP-PCR profiles and belonged to the O1a serotype. Fingerprints were identical to the reference strain CECT 955 (serotype O1a). The information obtained will be used for epidemiological purposes by health authorities and for the development of a vaccine against Y. ruckeri, a prominent request made by fish farmers in Peru.

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Leptospirosis is a zoonotic disease caused by the genus Leptospira, presenting complex and dynamic epidemiology. To determine the genetic variability and its phylogenetic relationship of Leptospira spp isolates from three sources in Iquitos (Peruvian Amazon) from 2002 to 2013, seven MLST genes were analyzed to obtain the Sequence Type (ST) and these sequences were concatenated for phylogenetic analysis. The genetic relationship between STs was determined with the goeBURST algorithm and genetic diversity was determined using DnaSP. Of 51 isolates, 48 were pathogenic belonging to five different species: Leptospira interrogans Nascimento 2004, Leptospira santarosai Feil 2004, Leptospira noguchii Haake 2021, Leptospira borgpetersenii Levett 2021, and Leptospira kirschneri Levett 2021. Of 20 STs identified, 60% corresponded to new genotypes circulating only in Peru. The genotypes ST17, ST37, and ST301 were recorded in rodents and humans. A high intraspecific genetic diversity was demonstrated in L. noguchi. The goeBURST analysis revealed three clonal complexes (CCs) and 16 singletons. The STs were found to show high genetic variability and phylogenetic and goeBURST analysis determined that the genotypes found did not form specific groups according to the source of infection or origin, which confirms the zoonotic potential of these STs in an area highly endemic for leptospirosis.

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Hypoxia is currently one of the greatest threats to coastal ecosystems worldwide, generating massive mortality of marine organisms, loss of benthic ecosystems and a decrease in fishery production. We evaluated and compared the tolerance to hypoxia of two species from different habitats of the Peruvian coast, the Peruvian rock seabass Paralabrax humeralis and the Peruvian grunt Anisotremus scapularis. The effect of hypoxia was measured as a function of the exposure time (progressive and chronic) on the behavioural and physiological responses of the two species, as well as on the enzymatic activity associated with the oxidative stress response of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and alkaline phosphatase (AKP). The ventilatory frequency was measured at two different temperatures (16 and 22°C) under progressive hypoxia conditions to determine the ventilatory critical point (Vcp). A. scapularis showed a higher Vcp than P. humeralis, which was positively affected by temperature. The median lethal time of A. scapularis was 36 min at 60% of oxygen saturation, while P. humeralis showed no mortality after 31 days of exposure at 5% oxygen saturation. Different enzymatic activity (P < 0.05) between species under hypoxia was recorded, in SOD (gill and muscle) and AKP (blood). A general tendency, under hypoxia, to slightly increase LDH activity (except for blood in A. scapularis, P < 0.05) and SOD activity (mainly in muscle of A. scapularis, P < 0.05), and decrease AKP activity (mainly in liver of P. humeralis, P < 0.05) was observed. The response of P. humeralis to hypoxia goes through a reduction in activity and metabolism, so this species can be considered hypoxia-tolerant, allowing it to face hypoxia events during prolonged periods. On the other hand, A. scapularis response to hypoxia prioritizes avoidance mechanisms and, together with other adaptations, makes it especially vulnerable to hypoxia and able to be considered hypoxia-intolerant.

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Peru is one of the world's leading fishing nations and its seafood industry relies on the trade of a vast variety of aquatic resources, playing a key role in the country's socio-economic development. DNA barcoding has become of paramount importance for systematics, conservation, and seafood traceability, complementing or even surpassing conventional identification methods when target organisms show similar morphology during the early life stages, have recently diverged, or have undergone processing. Aiming to increase our knowledge of the species diversity available across the Peruvian supply chain (from fish landing sites to markets and restaurants), we applied full and mini-barcoding approaches targeting three mitochondrial genes (COI, 16S, and 12S) and the control region to identify samples purchased at retailers from six departments along the north-central Peruvian coast. DNA barcodes from 131 samples were assigned to 55 species (plus five genus-level taxa) comprising 47 families, 24 orders, and six classes including Actinopterygii (45.03%), Chondrichthyes (36.64%), Bivalvia (6.87%), Cephalopoda (6.11%), Malacostraca (3.82%), and Gastropoda (1.53%). The identified samples included commercially important pelagic (anchovy, bonito, dolphinfish) and demersal (hake, smooth-hound, Peruvian rock seabass, croaker) fish species. Our results unveiled the marketing of protected and threatened species such as whale shark, Atlantic white marlin, smooth hammerhead (some specimens collected during closed season), shortfin mako, and pelagic thresher sharks. A total of 35 samples (26.72%) were mislabeled, including tilapia labeled as wild marine fish, dolphinfish and hake labeled as grouper, and different shark species sold as "smooth-hounds". The present study highlights the necessity of implementing traceability and monitoring programs along the entire seafood supply chain using molecular tools to enhance sustainability efforts and ensure consumer choice.

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La escuticociliatosis es una enfermedad causada por ciliados del orden Scuticociliatida los cuales se caracterizan por su alto potencial para invadir al huésped, significando un serio problema en la acuicultura marina. El presente trabajo describe la infección con escuticociliados en lenguado Paralichthys adspersus en cautiverio. Los signos externos e internos de la infección incluyen zonas necróticas en el tegumento, abundante mucosidad, abultamiento de la cavidad visceral con acumulación de líquido ascítico, necrosis de las fibras musculares, licuefacción del cerebro, entre otros. Se identificó y caracterizó molecularmente al parásito ciliado como M. avidus, utilizando secuencias de gen mitocondrial citocromo oxidasa I (COI), y de los genes nucleares β-tubulina y la región de la subunidad menor rRNA 18S, mostrando una sinonimia con P. dicentrarchi. Todas las lesiones estuvieron invadidas de ciliados. A nivel histológico, se detectaron ciliados en casi todos los tejidos siendo el cerebro el órgano más parasitado. Los ejemplares infectados, acompañados de infecciones bacterianas secundarias predominantemente por Vibrio alginolyticus, después de un periodo de letargia mueren.

The Scuticociliatosis, a disease caused by ciliates from the order Scuticociliatida characterized by their high potential to in vade the host, is a serious problem in marine aquaculture. This paper describes scuticociliatosis infection in farmed flounder Paralichthys adspersus. External and internal signs of infection include necrotic areas in the tegument, abundant mucus, swelling of the visceral cavity with ascitic fluid accumulation, necrotic muscle fibers and brain liquefaction, among others. The ciliate parasite was molecularly identified and characterized as M. avidus, using sequences of mitochondrial gene cytochrome oxidase I (COI), and nuclear genes β-tubulin and the region of the small subunit 18S rRNA, showing synonymy with P. dicentrarchi . All lesions were infested by ciliates. Histologically, ciliates are detected in almost all tissues being the brain the organ more parasitized. The infected specimens associated with secondary bacterial infections, predominantly Vibrio alginolyticus, died after a lethargy period.

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Determinar la variabilidad genética y evaluar la utilidad de microsatélites (STR) en la determinación de paternidad en alpacas blancas huacaya, pertenecientes al Centro Piloto de Mejoramiento Genético Munay Paqocha y el Fundo Itita, de la Sociedad Peruana de Criadores de Alpacas y Llamas (SPAR) Puno. Realizar la genotipificación y selección de marcadores STR útiles para la asignación de paternidad y parentesco. Metodología: Se evaluaron 10 marcadores STR a partir de ADN aislado de sangre y de folículos pilosos de 183 individuos colectados al azar procedentes de dos rebaños. Resultados y Conclusiones: Se observó un alto nivel de variabilidad alélica en el total de individuos analizados, y la presencia de alelos exclusivos entre poblaciones, con frecuencias menores al 1,5% en los loci LCA37, LCA90, LCA5, VOLP92, YWLL36, YWLL44 y YWLL08. Se propone la incorporación de tres marcadores adicionales, VOLP92, LCA94 y LCA90 para los análisis de variabilidad genética en alpacas. Los valores de FIS (0,016), y FST (0,003) reflejaron bajo niveles de endogamia. El rebaño del Fundo Itita presentó una mayor Ho (0,858) respecto a la He (0,848), mientras que por el contrario el rebaño del Centro Munay Paqocha presentó un menor valor de la Ho (0,815) respecto a la He (0,848), con una tendencia al déficit de heterocigotos. Los 10 marcadores presentaron una probabilidad de exclusión de parentesco adecuada, con un valor superior al 99,9%, cuando se conoce el genotipo de ambos padres, y un poder de discriminación mayor a 0,90...

To determine the genetic variability and the selection of STR markers useful for the evaluation of inbreeding, assignment of paternity and kinship, and the genotyping of two breeding herds of white huacayas alpacas Vicugna pacos, from the Pilot Center for Genetic Improvement Munay Paqocha and Fundo Itita, in Puno Perú. Methodology: 10 STR markers were assessed in 183 individuals, randomly selected. Results and Conclusions: We observed a high level of allelic variability in the total individuals, and unique alleles among populations with frequencies lower than 1.5% in loci LCA37, LCA90, LCA5, VOLP92, YWLL36, YWLL44 and YWLL08. We propose the addition of three markers, VOLP92, LCA94 and LCA90 for the genetic variability analysis in alpacas. FIS (0.016) and FST (0.003) values reflected low levels of inbreeding. Fundo Itita herd showed higher Ho (0.858) than He (0.848), while the herd of Munay Paqocha showed lower Ho (0.815) respect to He (0.848), with trending heterozygote deficit. The 10 markers showed an appropriate exclusion relationship probability, with a value greater than 99.9% when the genotype of both parents was known, and a power of discrimination greater than 0.9...

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