ABSTRACT A comparative study of serum biochemical and hematological parameters from Andinoacara rivulatus and Ichthyoelephas humeralis in Los Ríos Province, Ecuador, was carried out. Two of the native species that are the most commercialized in Quevedo, Mocache and Fumisa, were identified; 60 specimens were captured in each area (180 total). A factorial design (3×2) was used: three habitat zones (Fumisa, Quevedo, and Mocache) and two species (A. rivulatus and I. humeralis). Sex, weight, length, serum biochemistry (total protein, albumin, globulin, albumin/globulin ratio, aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium, phosphorus, sodium, magnesium, and potassium), hematological parameters (hemoglobin, hematocrits, erythrocytes, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), total leukocytes, granulocytes leukocytes, and agranulocytes leukocytes) in fishes were determined. There was zone-species interaction for all indicators except MCH and MCHC (P < 0.05). For total proteins, albumins and ALT were for I. humeralis in Fumisa and Mocache zones (2.81, 1.57, and 326.67 g dL-1, respectively). In comparison, A. rivulatus was higher in Fumisa and Quevedo in globulins and the albumins/globulins ratio with 2.28 g dL-1 and 2.14, respectively. Electrolytes were found in low concentrations in the two species. For the hematological parameters, all presented significant differences (P < 0.05) except MCH and MCHC. For I. humeralis, its highest values were presented in hemoglobin with 13.37 g dL-1 in Fumisa, for MCV and total leukocytes (93.11 fL-1 and 8.03×103 μL-1) respectively, in the Mocache area. This study will provide essential tools in monitoring the health status of these fish species in particular and fish species in general.

Abstract: In this study the enrichment dietary effect with different crude protein levels (CP) and feed additives on growth, survival, feed conversion ratio (FCR), feed consumption (FC) and total hemocyte count (THC) in juvenile white shrimp Litopenaeus vannamei were evaluated. The study covered two bioassays: in the first one, juveniles were daily fed for 45 days with four experimental diets containing: (1) Control, commercial feed (35% CP); (2) 29% CP; (3) 32% CP; (4) 35% CP. After the 29% CP diet was selected, juveniles in bioassay II were daily fed for 45 days with a single CP diet complemented with probiotics: (1) Control, commercial feed (35% CP); (2) 29% CP; (3) 29% CP + Bacillus mix at 1×106 CFUg-1 feed; and (4) 29% CP + yeast mix at 1×106 CFUg-1 feed. Juvenile shrimp fed with experimental diets gained significantly more weight and increased survival, FCR, FC and THC compared with control diet. However, differences among experimental diets were not significant. In bioassay II, juvenile shrimp fed with experimental diet + feed additives significantly increased survival, FCR, FC and THC compared with control diet. Growth of juveniles significantly increased with 29% CP and 29% CP + yeast mix diets, compared with control group. Complementing the diet with yeast mix showed higher survival and THC of juveniles compared with the other experimental treatments. Different CP levels in shrimp diet improved growth, survival and circulating hemocytes, and addition of mixed yeast as feed additive induced better survival and immune response in juvenile shrimp.

Resumen: En este estudio se evaluó el efecto del enriquecimiento de dietas con diferentes niveles de proteína cruda (CP) y aditivos en el crecimiento, supervivencia, tasa de conversión alimenticia (FCR), consumo de alimento (FC) y conteo total de hemocitos (THC) en juveniles de camarón blanco Litopenaeus vannamei. El estudio consta de dos bioensayos: en el primero, los juveniles fueron alimentados diariamente por 45 días con cuatro dietas experimentales con diferente contenido de proteína: (1) Alimento comercial o control, CP 35%; (2) CP 29%; (3) CP 32%; (4) CP 35%. Después de seleccionar CP 29%, en el bioensayo II los juveniles fueron alimentados diariamente por 45 días con una dieta proteica complementada con probióticos: (1) Alimento comercial o control, CP 35%; (2) CP 29%; (3) CP 29% + mezcla de Bacillus a 1×106 UFCg-1 alimento; y (4) CP 29% + mezcla de levaduras a 1×106 UFCg-1 alimento. Los camarones juveniles alimentados con las dietas experimentales mostraron ganancia en peso significativamente mayor e incremento en supervivencia, FCR, FC y THC comparado con la dieta control. Sin embargo, no hubo diferencias significativas entre las dietas experimentales. En el segundo bioensayo, los juveniles alimentados con la dieta experimental + aditivos alimentarios incrementaron significativamente supervivencia, FCR, FC y THC comparado con la dieta control. El crecimiento de juveniles se incrementó significativamente con las dietas CP29% y CP29%+mezcla de levaduras, comparado con el crecimiento de la dieta control. La dieta complementada con la mezcla de levaduras mostró el valor más alto de supervivencia y THC de juveniles comparado con los demás tratamientos experimentales. Los diferentes niveles experimentales de CP incluidos en la dieta de camarón incrementaron crecimiento, supervivencia y hemocitos circulantes; la adición de una mezcla de levaduras como aditivo alimentario, indujo mejor supervivencia y respuesta inmune en juveniles de camarón.

ABSTRACT The objective of the research was to analyze the active methodologies and technological applications in the teaching-learning process in the transition from face-to-face to virtual, carried out as a consequence of the COVID-19 health emergency, in the educational institutions of Zone 1, 2, and 5 of Ecuador. The research focused on a quantitative study, under a descriptive exploratory study, based on a non-experimental design. The survey technique was applied by means of an online questionnaire to intentionally selected groups of pre-school, elementary, middle and high school educational institutions. The results showed that the active methodologies applied in education in times of COVID-19, in the educational institution of the initial, basic, middle and higher levels; executed from the internet, and with applications that are offered free of charge on the web guarantee the quality of education. Likewise, in Ecuadorian education the active methodology is applied, based on the resolution of projects, followed by collaborative and cooperative work. Likewise, teachers claim that students need communication skills and teamwork; in addition, they require continuous training, since this type of methodologies are mostly applicable in the face-to-face modality.

RESUMEN La investigación realizada tuvo como objetivo analizar las metodologías activas y las aplicaciones tecnológicas en el proceso de enseñanza aprendizaje en la transición de lo presencial a lo virtual, realizado como consecuencia de la emergencia sanitaria de la COVID-19, en las instituciones educativas de la Zona 1, 2, y 5 del Ecuador. La investigación se enfocó en un estudio cuantitativo, bajo un estudio exploratorio descriptivo, a partir de un diseño no experimental. Se aplicó la técnica de la encuesta a través de un cuestionario online a grupos seleccionados intencionalmente de las instituciones de educativa inicial, básico, media y superior. Los resultados demostraron que las metodologías activas aplicadas en la educación en tiempos de COVID- 19, en la institución educativa de los niveles inicial, básica, medio y superior; ejecutadas desde el internet, y con aplicaciones que se ofertan de forma gratuita en la web garantizan la calidad de la educación. De la misma manera, en la educación ecuatoriana se aplica la metodología activa, basada en la resolución de proyectos, seguidas del trabajo colaborativo y cooperativo. Asimismo, los docentes alegan que se necesita de parte de los estudiantes habilidades de comunicación y el trabajo en equipo; además, requieren de una formación contante, ya que este tipo de metodologías son aplicables mayormente en la modalidad presencial.

ABSTRACT The master's program proposed by the Technical State University of Quevedo will contribute to the development of new knowledge to promote good aquaculture practices and train professionals with scientific and humanistic vision framed to the theoretical perspective raised in the objectives of the National Development Plan 2017-2021 - Toda una Vida, and to the zonal agenda 5, which concretely address national development objectives 4, 5, 6 and 7. The statistical analysis of the results allowed concluding, that the feasibility of the implementation of postgraduate studies in the proposed area has a high degree of acceptance by professionals, as they wish to improve their professional profile and develop competencies and skills in a specific area of study. 84.8% of the professionals interested in the program are between 21 and 30 years of age. All the proposed topics to be included in the master's program were selected by the respondents. In that sense, a population of 1800 professionals, 360 can opt for this master's degree, so there is sufficient demand for this 4th level academic offer in the Zonal Region 5.

RESUMEN El programa de maestría propuesto por la Universidad Técnica Estatal de Quevedo contribuirá al desarrollo de nuevos conocimientos para fomentar buenas prácticas acuícolas y formar profesionales con visión científica y humanista enmarcados a la perspectiva teórica planteada en los objetivos del Plan Nacional de Desarrollo 2017-2021 - Toda una Vida, y a la agenda zonal 5, que abordan de forma concreta los objetivos nacionales de desarrollo 4, 5, 6 y 7. El análisis estadístico de los resultados permitió concluir, que la factibilidad de la implementación de estudios de posgrado en el área propuesta tiene un alto grado de aceptación por parte de los profesionales, ya que estos desean mejorar su perfil profesional y desarrollar competencias y habilidades en un área específica de estudio. El 84,8% de los profesionales interesados en el programa tienen una edad entre 21 a 30 años. Todas las temáticas propuestas que incluirán en el programa de maestría se seleccionaron por los encuestados. En ese sentido, una población de 1800 profesionales, 360 pueden optar por esta maestría, por lo que existe suficiente demanda para esta oferta académica del 4to nivel en la de la Región Zonal 5.

RESUMO: Nós medimos o efeito de baixa, normal e alta salinidade (5, 35 e 50ppt) na digestibilidade aparente da matéria seca, proteína e energia em duas dietas formuladas e seis comerciais para camarão juvenil do Pacífico, Litopenaeus vannamei. Os coeficientes de digestibilidade aparente da matéria seca, proteína e energia foram determinados in vivo utilizando o óxido crômico como marcador inerte nas dietas (peso inicial médio de 4g), em um teste de 120 dias. Hidrostabilidade na dieta de 86,8% a 99,9%, os coeficientes de digestibilidade da matéria seca variaram de 49,1 a 64,1%, os coeficientes de digestibilidade da proteína apresentaram maiores variações em todas as salinidades (56,9-85,8%), enquanto os coeficientes de digestibilidade da energia variaram de 70,1 a 86,4%. Efeito significativo da salinidade na digestibilidade da matéria seca, proteína e energia foi encontrado. Esses resultados, usando a análise de componentes principais (PCA) com a matriz de covariância, sugerem que a dieta E2 (fórmula à base de farinha de peixe) e salinidade a 35 ppt é ideal para a hidrostabilidade e digestibilidade das dietas para juvenis de camarão-branco-do-Pacífico.

ABSTRACT: This study evaluated the effect of low, medium, and high-water salinity (5, 35, and 50 ppt) on the apparent dry matter, protein, and energy digestibility of two formulated and six commercial diets for juvenile whiteleg shrimp, Litopenaeus vannamei, in a 120-day trial. Digestibility was determined in vivo using chromic oxide as an inert diet marker. Hydrostability in pellets varied from 86.8% to 99.9%; dry matter digestibility varied from 49.1% to 64.1%; protein digestibility showed greater variations at all salinities (56.9%-85.8%); and energy digestibility ranged from 70.1 to 86.4%. Salinity had a significant effect on dry matter, protein, and energy digestibility. Using a principal component analysis (PCA) with a covariance matrix, our findings suggested that the E2 (fishmeal-based formulation) diet and 35 ppt salinity provided optimum hydrostability and digestibility to Pacific white leg shrimp juveniles.

Abstract The objective of this work was to determine the effect of age and climate on the chemical composition of Cenchrus purpureus in degraded ecosystems of Cuba. An experiment was carried out in two well-defined periods: slightly rainy (January to April) and rainy (July to October). The treatments (regrowth ages: 30, 45, 60, 75, 90 105 days) were distributed in a randomized block design with four replicas. The structural constituents of the cell wall, minerals (calcium and phosphorus), and digestibility of dry and organic matter were determined. The neutral detergent fiber showed a behavior defined by the climatic season (72.37%) in rains and 69.67% in few rains). The elements of the climate showed a high relationship with the chemical composition and linear regression models were adjusted with high coefficients of determination, greater than 0.71 in the two periods evaluated; the rainfall and maximum temperature variables were the ones that provided the greatest adjustments. With the increase in age, the quality of the plant decreased, and of climatic factors, rainfall and maximum temperature are those that most affect the nutritional quality of the plant.

Resumen El objetivo del presente trabajo fue determinar el efecto de la edad de rebrote y del clima en la composición química del Cenchrus purpureus en ecosistemas degradados de Cuba. Se realizó un experimento en dos períodos bien definidos: poco lluvioso (enero a abril) y lluvioso (julio a octubre). Los tratamientos (edades de rebrote: 30, 45, 60, 75, 90 105 días) se distribuyeron en un diseño de bloques al azar con cuatro réplicas. Se determinaron los constituyentes estructurales de la pared celular, minerales (calcio y fósforo), y digestibilidad de la materia seca y orgánica. La fibra detergente neutra mostró un comportamiento definido por la estación climática (72,37% en lluvias y 69,67% en pocas lluvias). Los elementos del clima mostraron alta relación con la composición química y se ajustaron modelos lineales de regresión con elevados coeficientes de determinación, superiores a 0,71 en los dos períodos evaluados; las variables lluvias y temperatura máxima fueron las que proporcionaron mayores ajustes. Con el incremento de la edad disminuyó la calidad de la planta, y de los factores climáticos, las precipitaciones y temperatura máxima son las que más afectan la calidad nutritiva de la planta.

ABSTRACT Coastal lagoons are an important component of the Gulf of California as they are considered natural ecosystems with high productivity and home to species of regional economic interest such as the striped mullet (Mugil cephalus), which, for its eating habits tends to present parasitism. The objective of the present work was to identify and determine the number of nematode parasites in the striped mullet in three lagoon systems (Navachiste, La Reforma, and Ceuta) in coastal areas of the southern Gulf of California. Thirty Mugil cephalus were randomly obtained from each of the lagoon systems. From each fish was obtained the total length, weight and condition factor (FC), next was dissected to be analyzed hepatosomatic index (HSI) and determine by direct count the prevalence, average intensity and average abundance of nematode; nematodes are identified taxonomically and molecularly. The nematode parasites found to belong to the genus Contracaecum of the family Anisakidae in all the fish sampled the parasitic prevalence was 67%. The nematode parasites found by sex indicated that 77% of the striped mullet females analyzed were parasitized, while the males presented 59%. The CF obtained was 1.17- 4.07, and the HSI ranged between 0.85 and 1.45; the average intensity for nematodes was 7.45, and the average abundance was 4.97, demonstrating that Contracaecum multipapillatum is the main nematode parasite present in all lagoon systems the southern Gulf of California.

ABSTRACT The environmental problems that plague humanity are urgent to be solved. Therefore, professionals are required to be trained under an ethical conscience with respect to the current situation of the environment. The objective of this work is to show a set of actions so that the students of the Zootechnics career can identify and act from the subject of Animal Health on the environmental problems that derive from bad livestock practices. The proposed set of actions propitiates, from a teaching developer and integrator process, an integral professional formation of the future graduated, so that in this future field of action, they can guarantee sustainable livestock productions on the basis of an adequate sanitary management.

RESUMEN Los problemas medioambientales que azotan a la humanidad resultan apremiantes de solución. Por tanto, se requiere de profesionales que se formen bajo una conciencia ética con respecto a la situación actual del medio ambiente. El presente trabajo tiene como objetivo mostrar un conjunto de acciones para que los estudiantes de la carrera de Ingeniería Zootécnica puedan identificar y accionar, desde la asignatura Sanidad Animal sobre los problemas medio ambientales que se derivan de las malas prácticas pecuarias. El conjunto de acciones propuesto propicia, desde un proceso docente desarrollador e integrador, una formación profesional integral del futuro egresado, para que en su futuro campo de actuación pueda garantizar producciones pecuarias sostenibles sobre la base de un manejo sanitario adecuado.

ABSTRACT Using a random block design and five replications (the experimental unit was the five-meter-long furrow), the evaluation of eight Cenchrus purpureus varieties obtained by in vitro tissue cultures with possible salinity tolerance (CT- 501, 502, 503, 504, 505, 506, 507 and 508) was performeddime and were compared with their progenitor (Cenchrus purpureus cv. Cuba CT-115). The experiment was developed in the Estación Experimental de Pastos y Forrajes (EEPF) belonging to the IIA "Jorge Dimitrov", Bayamo, Cuba. After the establishment cut, measurements every 15 days from 30 to 105 regrowth days were taken, in the rainy and dry seasons of the year. The analysis of the main components showed that the yield, leaf width, leaf area, length and width of the internode, leaves percent and height explain 93.14 % of the variability between varieties in the rainy season, while in the dry season the 86.12 % of the variability was explained through the width and length of the internode, length and width of leaves, leaves percent, yield and leaf area. The cluster analysis showed the presence of five and four groups of varieties for the periods mentioned, where the CT-508 is highlight for its higher height and yield. The multivariate analysis showed the agronomic indicators that most contribute to explain the variability among the varieties and it is suggested to deep into the bromatological indicators to develop management strategies for this region.

RESUMEN Mediante un diseño de bloques al azar y cinco réplicas (la unidad experimental fue el surco de cinco metros de longitud) se realizó la evaluación de ocho variedades de Cenchrus purpureus obtenidas por cultivos de tejidos de in vitro con posible tolerancia a la salinidad (CT-501, 502, 503, 504, 505, 506, 507 y 508) y se compararon con su progenitor (Cenchrus purpureus vc. Cuba CT-115). El experimento se desarrolló en la estación experimental de pastos y forrajes (EEPF) perteneciente al IIA ¨Jorge Dimitrov¨, Bayamo, Cuba. Después del corte de establecimiento se realizaron mediciones cada 15 días desde los 30 hasta 105 días de rebrote, en los períodos lluviosos y poco lluvioso del año. El análisis de componentes principales indicó que el rendimiento, ancho de la hoja, área foliar, longitud y ancho del entrenudo, por ciento de hojas y altura explican el 93.14 % de la variabilidad entre variedades en el período lluvioso, mientras que en el período poco lluvioso el 86.12 % de la variabilidad se explicó a través del ancho y longitud del entrenudo, longitud y ancho de las hojas, por ciento de hojas, rendimiento y área foliar. El análisis de conglomerado evidenció la presencia de cinco y cuatro grupos de variedades para los períodos antes señalados, donde se destaca la CT-508 por su mayor altura y rendimiento. El análisis multivariado demostró los indicadores agronómicos que mayor aporte hacen para explicar la variabilidad entre las variedades y se sugiere profundizar en los indicadores bromatológicos para trazar estrategias de manejo para esta región.

ABSTRACT The effect of different proteins and lipids levels on antioxidant response of superoxide dismutase (SOD) was tested in muscle, hepatopancreas and whole-body tissues of cauque river prawn Macrobrachium americanum juvenile. Six diets with two crude protein (35 and 40% diet) and three lipid levels (6, 10, and 14% diet) were tested for juveniles in a factorial manner (3×2), to provide six different dietary. Juvenile prawns (0.22 ± 0.03 g) were randomly placed in 18 plastic tanks (160 L), at a density of 15 juveniles per tank (3 tank replicates/treatment). The assay lasted 60 days. SOD activity was significantly different in muscle, hepatopancreas and whole body depending on proteins and lipids levels in the diet. Results indicate that the diet containing 35% protein and 10% lipid provided adequately to while preventing diet-induced oxidative stress and protecting the integrity of the antioxidant response of SOD.

ABSTRACT The effect of five diets with different crude protein levels (27, 33, 38, 43, and 48%) on growth and survival of Macrobrachium americanum prawns was determined. Optimum dietary protein level was also calculated. Specimens were collected in the Coyuca River, Guerrero, Mexico, and classified into seven weight groups with 0.67 g intervals amplitude. Five diets with different levels of crude protein were formulated and supplied to individuals of the seven weight groups as an experimental treatment. Weight gain percentage (WG%), specific growth rate (SGR), food intake (FI), protein intake (PI), protein efficiency ratio (PER), food conversion ratio (FCR) and survival rate (SR) were calculated weekly along the 70 days experiment. A quadratic model was fitted to weekly mean weight gain and to WG% rates data to estimate protein requirement for every week of the experiment and weight group. A mortality model was also fitted to mortality data to compare mortality trend among the different experimental diets. 33% protein level resulted in the best treatment because of the parameters calculated, cost to produce and survival trend. Weekly optimum level of protein calculus varied on a range from 39.4 to 43.3% and optimal crude protein percentage for the seven weight ranges was between 49% for smaller prawns (0.248-0.918 g) and 35.7% for the larger prawns (4.271-4.940 g). Thus, it is recommended juvenile feeding prawns with different crude protein levels while the culture time elapses to achieve the maximum weight gain.