Resumen: Un pez nativo cada vez más estudiado en Latinoamérica es el Dormitator latifrons, pero se desconoce el efecto de altas densidades de siembra en su fisiología. El objetivo fue determinar el efecto de diferentes densidades de siembra en el crecimiento y parámetros sanguíneos. Se utilizaron organismos silvestres aclimatados al cautiverio, alimentados al 4% de biomasa total durante 60 días. Se registró peso y longitud inicial y final, determinando índices de crecimiento y supervivencia. Al final del experimento se tomó una muestra de sangre al total de organismos para evaluar parámetros sanguíneos No se encontraron diferencias en el crecimiento y supervivencia entre las diferentes densidades. Los parámetros sanguíneos no fueron afectados por la densidad, a excepción del estallido respiratorio, todos se encuentran entre los rangos de referencia de buena salud para peces. La especie no presentó señales de estrés o respuesta inmune adversa asociada al incremento de la densidad de cultivo.

Abstract: The native fish Dormitator latifrons culture technology in Latin America has increased, but the effect of high stocking densities on the physiology of the species is still unknown. The objective of this study was to analyze the effect of different stocking densities on growth and blood parameters. Wild organisms were acclimatized to culture conditions, and fed daily at 4% of total biomass, during 60 days. The weight and length of the organisms were recorded at the beginning and end of the experiment, growth and survival rates were determined. At the end of the experiment, a blood sample was taken from all fish for blood parameters evaluation. No differences in growth and survival were found between the different densities tested. Blood parameters were not affected by stocking density. All blood parameters are within the reference ranges indicating good fish health, except respiratory burst. The fish did not show signs of stress or any negative immune response at all culture densities tested.

ABSTRACT In order to provide information on the current knowledge about the native fish Dormitator latifrons and identify the gaps that must be filled to achieve correct resource management, a scientometric study was carried out using different scientific databases. A total of 103 publications were registered between the years 1972 and 2021. Results indicate that the species has been addressed since 2001 with less than one publication per year, with 2008 being the year with the highest number of publications (10). The main topics addressed were ecology, physiology, and parasitology of fish. The available knowledge generated about the species is concentrated in 68 journals, with Mexico as the most productive country, followed by USA and Ecuador, and the most productive research centers about this fish were Mexico’s Instituto Politécnico Nacional and Universidad de Guadalajara. A total of 285 authors were detected contributing knowledge to the species, with Violante-González in the top with ten publications. The co-authorship co-occurrence maps suggest there is no solid collaborative relationship between the scientific community and that the information generated is insufficient for conserving and exploiting this fish. It is essential to increase the study of thematic areas that allow their comprehensive management in the medium term; topics like reproduction in captivity, aquaculture, and nutrition must be addressed in the future to assure a sustainable use of this resource.

Abstract The relationship of body weight and length with sperm load and spermatophore weight was evaluated in wild males of Macrobrachium tenellum (Smith, 1871). In addition, the influence of a commercial and natural feed on the load and viability of sperm was determined in wild males. In 28 wild males spermatophore extraction was performed by electrostimulation 24 h after capture to analyze the relationship between body length/weight and sperm load and viability, respectively. Spermatophore weight (SW), total number (TS), dead (DS) and abnormal sperm cells (AS) were used as indicators of sperm viability. The results obtained show that there is a positive correlation between TS per spermatophore compared to body length and weight of the male. To study the effect of different diets on sperm load, three diets were employed: Diet A, commercial shrimp feed; Diet B, natural feed (mixture of squid, sardine and clam); and Diet C, combination of natural and commercial diet. To assess the initial reproductive status of the males at the beginning of the experiment, sperm viability was determined in a subsample of specimens after capture. Broodstock were fed ad libitum once a day during 70 days. TS, DS, AS and SW were evaluated. The results of the bioassay did not show differences between treatments in the parameters analyzed, except DS, which was higher in the initial group. In conclusion, the present work suggests that it is feasible to substitute fresh feed for an artificial diet for the maintenance in captivity of male M. tenellum broodstock shrimp.

ABSTRACT The development of native fish aquaculture represents an important alternative to mitigate ecological displacement generated by exotic fish. The introduction of native fish in polyculture systems with high commercial value fishes has provided a useful strategy for sustainable aquaculture development. The present study aims to provide information on tilapia, as an exotic species, and Dormitator latifrons, as a native species, in a duo culture not programmed as such. Using juveniles of Pacific fat sleeper D. latifrons leftovers from another experiment, we decide to analyze and report the biological feasibility of a duoculture system with this species and Nile tilapia (Oreochromis niloticus). Two hundred fifty organisms of each species were placed for 90 days in a concrete tank with a capacity of 50 m3 to evaluate the compatibility of these species. The biological variables measured were growth, survival, feed conversion rate, and protein efficiency. The findings suggest a good interaction between species, with adequate growths and a survival rate of 98%. No antagonistic behavior was observed during confinement, suggesting the duoculture of these species may represent a good alternative for tropical sustainable aquaculture.

ABSTRACT The present work is a review of the literature on the native Mexican fish Dormitator latifrons. The aim is to contribute to the integration and systematization of current knowledge to make it easier to identify existing knowledge gaps and breakthroghs Moreover, promote the successful cultivation and protection of this species whose consumption is increasing in Latin America. A review of the articles related to D. latifrons published in international and regional databases was carried out. The articles reviewed focus on taxonomy and systematics, phylogenetic, geographic distribution, ecology, physiology, reproduction, development, pathology, health, and the technologies used to cultivate this fish species. The conclusion is that, even though the cultivation of D. latifrons is of commercial interest in some countries, there are still significant gaps in our knowledge of biology and, consequently, the domestication potential of the species. Filling these gaps will require systematic research efforts on protecting natural populations and improving mass cultivation techniques.

ABSTRACT Groups of Dormitator latifrons in triplicate (4.1 ± 2.0 g and 6.2 ± 1.0 cm) were fed experimental diets containing four levels of substitution of fishmeal (FM) by soybean meal (SM) (0, 40, 70, and 100%, respectively). The diets were formulated to be isoproteic (35% crude protein) and isolipidic (8.0% crude lipids). The effect of each treatment on growth was evaluated and its implications on the cost of feeding. After 60 days of feeding, there were no significant differences in the fish’s proximate composition (P < 0.05). There were no significant differences between the diets (P < 0.05) in the evaluated biological indices: total growth increase (TGI), specific growth rate (SGR), thermal growth coefficient (TGC), and survival (%). Feeding costs decreased significantly as the proportion of soybean meal in the diet increased. The results indicated that substituting FM by up to 100% of SM can promote adequate growth in D. latifrons without affecting body composition and survival while also reducing operative costs during the fattening process.

Abstract Understanding the upstream migration of amphidromous prawns is important to address the impact of anthropomorphic activities in natural freshwater ecosystems. The ability of Macrobrachium tenellum (Smith, 1871) juveniles to overcome an artificial barrier was evaluated, simulating an obstacle in their upstream migration, under an experimental laboratory system. The prawns were collected from a stream located in Puerto Vallarta, Mexico (N = 1000). An experimental recirculation system was used, which consisted of a tank with a capacity of 600 L, a sheet of galvanized steel that acted as an anthropogenic barrier and two submersible electric pumps with flows of 0.12 L/s and 0.40 L/s. In this system, two inclinations of the barrier were tested, 45° and 90° in combination with the two flows. The results show that there are significant differences between the treatments with different inclinations, where a higher stimulation response was observed at the 90° angle. Within this inclination, the flow of 0.40 L/s produced the highest stimulation to climb the barrier in prawns between 30 and 60 mm in length. This study demonstrates the direct relationship between the slope and the effect of water flow of the anthropogenic barriers that hinder the migration process of M. tenellum.

ABSTRACT Dormitator latifrons is an amphidromous fish species distributed on the Pacific coastal region from California to Peru. It has a high potential to be cultured in Mexico. However, there is very little information about its biology, physiology and culture. This research study is a contribution to the hematology and blood chemistry of this native species. Results show hematocrit values of 28%, erythrocytes 2.075×106 mm3, leukocytes 35.035×103 mm3, mean corpuscular volume 161.547 fL, NBT 0.39, glucose 51.467 mg dL−1, protein 3.936 g dL−1, albumin 1.906 g dL−1, globulin 2.391 g dL−1 and albumin/globulin ratio 0.686.

ABSTRACT The objective of this work was to assess the acceptance of live and inert food by Macrobrachium tenellum during the early larval stages. The larvae were obtained by collecting wild ovigerous females in the Ameca River in the State of Jalisco, Mexico. Eight treatments (diets) were used to feed the larvae: D1, control (fasting); D2, micro-pulverized food (Purina®); D3, living, newly hatched nauplii of Artemia franciscana (INVE®, Salt Lake City, Utah, USA); D4, commercial paste containing microalgae (Instant Algae Rotifer Diet®); D5, water extracted from a biofloc system; D6, cooked egg yolk; D7, newly hatched and frozen nauplii of A. franciscana (INVE®, Salt Lake City, Utah, USA); D8, nutritional supplement for shrimp larvae (Epifeed LH1®). Treatments D2, D5, D6 and D8 showed traces of food in the digestive system. The larvae did not consume D3 and D7 treatments. The diets that had more acceptance were micro-pulverized food, a nutritional supplement for shrimp larvae Epifeed® LH1, cooked egg yolk, and biofloc water.

ABSTRACT Dormitator latifrons inhabits a wide range of salinities as a result of its migratory and reproductive cycle. The objective of the study was to evaluate the physiological response time and survival to saline change under laboratory conditions. The basal gill ventilation frequency (GVF) of organisms was recorded at 33 ups (SW) and in freshwater at 0.3 ups (FW). The gill ventilation frequency of organisms that were transferred from FW-SW and inversely from SW-FW (15, 25, and 33 ups) was counted, in triplicate, for 1 minute and 1, 4, 24 and 48 h. Statistical differences (p < 0.05) were found in fish transferred from FW-SW and SW-FW at the first minute with respect to basal GVF. In all treatments the organisms recovered their GVF one hour after being exposed to saline modification. There was 100% survival in all treatments. D. latifrons has a rapid physiological response to sudden changes in salinity.

RESUMEN Dormitator latifrons habita en un amplio intervalo de salinidades producto de su ciclo migratorio y reproductivo. El objetivo del trabajo fue evaluar el tiempo de respuesta fisiológica y la sobrevivencia al cambio salino en condiciones de laboratorio. Se registró la frecuencia ventilatoria branquial (FVB) basal de organismos a 33 ups (AS) y en agua dulce 0.3 ups (AD). Se contabilizó la frecuencia ventilatoria branquial de organismos que fueron transferidos AD-AS e inversamente AS-AD (15, 25, y 33 ups), por triplicado, durante 1 minuto, 1,4, 24 y 48 h. Se encontraron diferencias estadísticas (p < 0.05) en los peces transferidos de AD-AS y AS-AD al primer minuto con respecto a FVB basal. En todos los tratamientos los organismos recuperaron la FVB una hora después de ser expuestos a la modificación salina. Se tuvo un 100% de sobrevivencia en todos los tratamientos, D. latifrons tiene rápida respuesta fisiológica a cambios bruscos de salinidad.

ABSTRACT The native fish Dormitator latifrons, also known as chame, popoyote, puyeque and Pacific fat sleeper, grows in brackish environments in estuaries of the American Pacific coast, from Baja California (Mexico) to Perú. It is consumed regionally, and its characteristics under culture conditions are currently being evaluated. This study compared the proximate composition and fatty acid profile of wild and cultured specimens of D. latifrons to determine the effect of feeding them a commercial diet for tilapia under culture conditions. The protein content of the muscle of wild fish was higher than that of cultured fish, but the total lipid content was lower. The levels of fatty acids C18:1n9 and C18:2n6 were significantly higher (P < 0.05) in cultured fish, while the levels of C20:5n3 (EPA) and C22:6n3 (DHA) were significantly higher (P < 0.05) in wild fish. The n3/n6 ratio was higher in wild fish. These results show that D. latifrons is a species that can be readily cultured and that quickly gets used to formula feed. However, given the fatty acid composition of this species, it is necessary to control the quality of oil in the diet.

Abstract Background: Different methods are currently used for the prevention and control of diseases in aquaculture. Prophylaxis with immunostimulants from microscopic fungi provides protection against diseases and increases resistance to parasites. In this context, Basidiomycota fungi could have high potential for use in aquaculture because they contain different compounds, such as fungal proteins, polysaccharides, terpenoids, vitamins, and minerals, which could work as immunostimulants. Goals: Collect and disseminate the information on species of macroscopic fungi that have been used as immu nostimulants in the farming of teleost fish and the fungi that have not been tested in fish but have shown positive results in other organisms. Methods: We gather, discuss and compare the experimental, scientific and theoretical literature related to the immunostimulant effect of macroscopic fungi in the cultivation of teleosts, as well as fungi whose stimulating effect has been positive in other organisms. Results: We evaluated more than 50 species of fungi with immunostimulating properties. Nevertheless, in recent years, the effects of only eight species of macromycetes, belonging to the genera Ganoderma, Inonotus, Lentinula, Pleurotus, and Trametes, have been evaluated in 17 published papers regarding the immune response of nine species of fish. Seven of these papers are about isolated glucans, six about crude and alcoholic extracts, two about pulverized basidiomata, and one about a mushroom fermented by-product. Conclusions: Due to the limited information on the immunostimulating effect of macromycetes on fish, more research is needed regarding other fungi species with immunostimulant properties, the correct determination of fungi species, their culture, and in vivo and in vitro tests that confirm their immune system effects on the model organism and target organism.

Resumen Antecedentes: Actualmente se utilizan diferentes métodos para la prevención y control de enfermedades en la acuicultura. La profilaxis con inmunoestimulantes a partir de hongos macroscópicos proporciona protección ante enfermedades y aumenta la resistencia a parásitos. En este contexto, los hongos Basidiomycota podrían tener un alto potencial para su uso acuícola, ya que contienen diferentes compuestos, como proteínas fúngicas, polisacáridos, terpenoides, vitaminas y minerales, que podrían tener un efecto inmunoestimulante. Objetivos: Analizar la información existente relativa a las especies de hongos macroscópicos que han sido evaluadas como inmunoestimulantes en el cultivo de peces teleósteos y también la de aquéllos que no han sido probados en peces pero que han mostrado resultados positivos en la respuesta inmune en otros organismos. Métodos: Se reunió, expuso y comparó la literatura experimental, científica y teórica relacionada con el efecto inmunoestimulante de los hongos macroscópicos en el cultivo de teleósteos así como la relativa a hongos cuyo efecto estimulante ha sido positivo en otros organismos. Resultados: Actualmente se han comprobado las propiedades inmunoestimulantes de más de 50 especies de hongos macroscópicos. No obstante, en 17 investigaciones publicadas durante los últimos años sólo se ha evaluado el efecto sobre la respuesta inmune de nueve especies de peces ante ocho especies de hongos: Ganoderma, Inonotus, Lentinula, Pleurotus, Phellinus y Trametes. De dichas publicaciones, siete consisten en la evaluación de glucanos purificados, seis de extractos crudos o alcohólicos, dos de basidiomas pulverizados y uno de un subproducto de hongo fermentado. Conclusiones: Debido a la escasa información existente sobre el efecto inmunoestimulante de macromicetes en peces, es preciso llevar a cabo más investigaciones que aborden su potencial en otras especies, que se estudie su cultivo y su correcta determinación, y se realicen pruebas in vitro e in vivo, tanto del organismo modelo como de organismos blanco, para confirmar sus efectos sobre el sistema inmune.

ABSTRACT In this research it was evaluated the effect of background color on the development of the chromatophores in Macrobrachium tenellum prawns, six juvenile prawns were exposed to five background colors: black, white, pink, red, white and green; each one in triplicate, for 60 days. The development of the chromatophores was evaluated by means of the chromatophores index using a scale of 1 (the maximum concentrated pigment) to 5 (the maximum dispersed pigment). The coloration was analyzed in four anatomical regions of the organisms with the HSB model (hue-saturation-brilliance). The results show that the prawns modify their pigmentation according to the different background colors of experimental aquariums.

ABSTRACT: Dormitator latifrons is a fish with commercial potential that inhabits environments with tropical and subtropical climates from southern California (USA) to Peru. The objective was to determine the nutritional requirements of protein and lipids for the growth of juveniles; four experimental diets were prepared with protein contents of 30 and 40%, and lipids of 8 and 16%, with three repetitions per treatment. Proximal analysis of the experimental diets, of the muscle at the beginning and at the end of the experiment, was carried out and the apparent digestibility was determined. No significant differences (p > 0.05) were detected in the growth, survival and proximal composition of the fish muscle. The apparent digestibility of the diet with 30% protein and 8% lipids was significantly higher than the rest of the diets, so it is considered sufficient for adequate growth of D. latifrons juveniles.

RESUMEN: Dormitator latifrons es un pez con potencial comercial que habita ambientes con climas tropicales y subtropicales desde el sur de California (EEUU) hasta Perú. El objetivo fue determinar los requerimientos nutricionales de proteína y lípidos para el crecimiento de juveniles, se elaboraron cuatro dietas experimentales con contenidos de proteína del 30 y 40%, y lípidos del 8 y 16%, con tres repeticiones por tratamiento. Se realizó el análisis proximal de las dietas experimentales, del músculo al inicio y al final del experimento y se determinó la digestibilidad aparente. No se detectaron diferencias significativas (p > 0.05) en el crecimiento, supervivencia y la composición proximal del músculo de los peces. La digestibilidad aparente de la dieta con 30% de proteína y 8% de lípidos fue significativamente superior al resto de las dietas, por lo que se considera suficiente para un adecuado crecimiento de juveniles de D. latifrons.

Abstract Aquafeed quality for striped bass (Morone saxatilis) was evaluated under commercial conditions in sea cages using stable isotopes as tracers for nitrogen. Using a crossover experimental design, fish that were fed during 270 days with aquafeed "A" was switched to aquafeed "B" during the following 160 days. Samples of aquafeeds and of muscle, and liver tissues were analyzed before and during feeding with aquafeed "B". The isotopic value from diet "A" and muscle and liver tissues after being fed during 270 days were 10.3, 14.6 and 13.1‰ resulting in a discrimination factor of 4.3 and 2.7 for muscle and liver. At day 90 and 160 the discrimination factor reach the equilibrium both for muscle and liver tissues (2.3 and 0.0). It was concluded that diet "B" hadbetter quality as a result of a lower discrimination factor than that observed with diet "A". The nitrogen stable isotope is a reliable tool to evaluate aquafeeds quality under commercial conditions where the other estimations like feed intake and apparent digestibility are difficult to obtain.

Resumen La calidad entre dos alimentos comerciales ("A" y "B") se evaluó utilizando isótopos estables como trazadores de la retención de nitrógeno (δ15N) en lobina rayada (Morone saxatilis) mantenidas en jaulas marinas. Con base en un diseño cruzado, se utilizaron peces que habían sido alimentados durante 270 días con el alimento "A", mismos que fueron cambiados al alimento "B" durante otros 160 días. Se analizaron muestras de los alimentos comerciales y de tejido de músculo e hígado antes y durante la alimentación con el alimento comercial "B", para determinar su composición química e isotópica. El valor isotópico de los alimentos comerciales, músculo e hígado, al término de la alimentación con el alimento "A" fue de 10.3, 14.6 y 13.1‰, lo que refleja un factor de discriminación para músculo e hígado de 4.3 y 2.7, respectivamente. Al hacer el cambio al alimento "B" (11.09‰), se observó una reducción en los valores isotópicos. Para los días 90 y 160, los valores de discriminación ya eran casi constantes tanto para músculo como para hígado (2.3 y 0.0). Se concluye que el alimento "B" presentó una mejor calidad al incorporarse con un menor factor de discriminación que lo observado con el alimento "A". La técnica de isótopos estables demostró ser una herramienta útil para monitorear la calidad del alimento bajo condiciones comerciales, ya que mide directamente la eficiencia de la retención del nitrógeno, mientras que en otras pruebas como las de consumo y de digestibilidad aparente, es difícil de obtener.