Pablo Emilio Cruz-Casallas’s research while affiliated with University of the Llanos and other places

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Publications (11)


Fig. 1. Total sperm abnormalities found in fresh and cryopreserved Piaractus orinoquensis sperm at 24 h, 1, 6 and 12 months. Bars represent the mean ± standard deviation (mean ± SD). Different letters indicate significant differences (P < 0.05). h: hours, m: months.
Fig. 3. Scanning Electron Microscope images of Piaractus orinoquensis spermatozoa. A) fresh spermatozoa (10.0 KV; SP= 9.0; WD=12.4; x 5.0 K). B: Spermatozoa cryostored for 12 months (10.0 KV; SP= 12.0; WD=12.3; x 5.0 K). Spermatozoa with cryo-damage at head level (white arrows). KV: voltage acceleration; SP: spot size; WD: working distance; K: 1000.
Cryostorage of white cachama (Piaractus orinoquensis) sperm: Effects on cellular, biochemical and ultrastructural parameters
  • Article
  • Full-text available

January 2023

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142 Reads

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5 Citations

Aquaculture Reports

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Pablo Emilio Cruz-Casallas

To date, little attention has been paid to identifying the effects of long-term cryopreservation on sperm quality for Piaractus orinoquensis. The object of this study was therefore to evaluate the effect of long-term cryopreser-vation (24 h, 1, 6 and 12 months) on sperm motility, viability, DNA integrity, ATP content, total antioxidant capacity (TAC), morphology and sperm ultrastructure in this species. Milt samples from six males were cry-opreserved in a medium containing final concentrations of 7.5% Me 2 SO, 4.1% glucose and 9.0% egg yolk. The samples were frozen in liquid nitrogen (LN) vapor and stored in LN for periods of 24 h and 1, 6 and 12 months. After thawing, both the motility rate and the viability decreased significantly compared with fresh sperm; however, these parameters did not differ among the four cryopreservation times. The DNA integrity and ATP content decreased significantly after 6 months of cryopreservation. There were no significant differences in TAC values between fresh and cryopreserved sperm. The total sperm abnormalities in cryopreserved samples were about 5-fold higher than in fresh sperm; short tail was the most common defect occurring after cryostorage. The ultrastructural analysis reveals that P. orinoquensis spermatozoa consist of an ovoid head without acrosome, a cylindrical mid-piece, and a single flagellum. The nuclear fossa is located at the base of the nucleus and contains the centriolar complex. There are 1-2 ring-shaped mitochondria located in the mid-piece. The flagellum shows a 9 + 2 organization of microtubules in the axoneme. Post-thaw spermatozoa presented damage such as swelling and rupture of the plasma membrane, mitochondrial damage, loss of the electron-dense chromatin of the nucleus , and degeneration in the middle region.

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Descripción de los niveles de testosterona, estradiol y cortisol en Pseudoplatystoma metaense x Leiarius marmoratus

August 2022

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8 Reads

Revista de Medicina Veterinaria

Los esteroides desempeñan un papel importante en la coordinación de las actividades del eje hipotálamo-hipófisis-gónada, y su actividad en el control de múltiples procesos, incluidos el apareamiento y la reproducción, es fundamental. El presente estudio consistió en describir los niveles séricos de testosterona (T), estradiol (E2) y cortisol en ejemplares mayores de dos años de Pseudoplatystoma metaense x Leiarius marmoratus en condiciones de cautiverio. Se realizaron ocho muestreos durante los meses de enero a octubre. Fueron empleados nueve individuos híbridos entre machos y hembras (4:5, respectivamente), siendo seleccionados aleatoriamente 7 ± 2 individuos por cada muestreo. Las muestras de sangre obtenidas fueron procesadas y analizadas cada 40 - 45 días durante el periodo experimental. Los niveles de T en machos (0,65 ng/ml) y E2 en hembras (0,88 ng/ml) presentaron los picos más altos durante los meses de mayor pluviosidad en la región (junio – julio) que desencadenaron el inicio de la temporada reproductiva. Por un lado, los niveles de E2 en hembras posiblemente se encuentran asociados con la maduración ovárica y actividad de la aromatasa, en tanto que los machos mostraron descensos de 0,1 ng/ml durante junio - julio; y un incremento máximo de 0,7 ng/ml para el mes de octubre. Por otro lado, los niveles de cortisol se incrementaron hacia la temporada de reproducción siendo mayores en hembras (18,8 – 25,4 ng/ml). Lo anterior puede indicar que, a pesar de altas concentraciones de cortisol, no se inhibió la producción de esteroides.



Cryopreservation of coporo (Prochilodus mariae) milt using three permeating cryoprotectant agents and two freezing systems

August 2021

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43 Reads

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3 Citations

In the present study, we examined three permeating cryoprotectant agents (CPAs) and two freezing systems for the cryopreservation of coporo spermatozoa. Milt samples of 5 males were diluted with cryoprotectant solutions containing 10% Me2SO, 10% MeOH and 8% DMA, respectively, with or without hen egg yolk. Half of the 0.25‐ml straws were frozen in a programmable system and the other half in a dry shipper. Sperm motility and viability were evaluated in both fresh and post‐thaw samples by conventional methods. Sperm motility and viability were both significantly lower in all post‐thaw treatments. Of the CPA tested, 10% MeOH provided the best protection as there were no significant differences in motility (66.67 ± 5.77% vs. 66.68 ± 5.70%) and viability (80.00 ± 4.35% vs. 83.33 ± 0.57) between the programmable system and the dry shipper when that CPA was used. On the other hand, the most effective freezing system was the programmable freezer as all the CPA tested presented sperm motility (43.33 ± 5.77 to 66.50 ± 5.00%). In conclusion, coporo sperm can be cryopreserved in either of these two systems using 10% methanol.


Gonadal Maturation in Pseudoplatystoma metaense x Leiarius marmoratus Hybrids, (Siluriformes: Pimelodidae)

October 2020

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53 Reads

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1 Citation

International Journal of Morphology

Establishing guidelines for responsible management in fish production systems requires knowledge of the basic biology of the fish to be raised. The objective of this work was to determine the reproductive capacity of hybrids produced from the crossing of females of Pseudoplatystoma metaense with males of Leiarius marmoratus. Males presented a digitiform, unrestricted spermatogonial testicle containing caudal digits producing glycoproteins that do not form a seminal vesicle. It was possible to find free sperm in the lumen of the tubules and in the ducts. The ovary of the females was found to be saccular and synchronous with at least three groups of oocytes. In the first year of life, only oogonia up to previtellogenic oocytes (cortical alveolus 284.9 ± 35.7 mm in diameter) were found. After the second year vitellogenic oocytes 730 ± 3.78 mm in diameter were observed. The events of gonadal development of the hybrids indicate that they are gonochoric, synchronic animals. The maturation peaks in the high-water season, overlapping with the parental species. Therefore, the escape of hybrids from fish cultures to the rivers may increase the risk of crosses, gene introgression, or diminution of the reproductive capacity of the pure species.


Fig. 1. Localización de los puntos de muestreo, cuerpos de agua aledaños a las comunidades indígenas de Yacayacá
(01°05’00,5”N - 070°28’19,4”W), Piracemo (01°19’55,8”N - 70°23’00,8”W) y Santa Cruz (01°09’27”N - 70°00’24,3”W)
en el departamento de Vaupés, Colombia.
Fig. 1. Location of sampling points, water bodies close by the indigenous communities of Yacayacá (01°05’00,5”N -
070°28’19,4” W), Piracemo (01°19’55,8”N -70°23’00,8”W) y Santa Cruz (01°09’27”N -70°00’24,3”W) at the department
of Vaupés, Colombia.
Fig. 2. Frecuencia de ocurrencia (%) de ítems alimenticios en peces Leporinus friderici muestreado desde marzo 2014 a mayo 2015. A. Valores que consolidan los tres sitios de muestreo. B. Yacayacá. C. Piracemo. D. Santa Cruz. Fig. 2. Frequency of occurrence (%) of food items Leporinus friderici fish sampled from the months of March 2014 to May 2015. A. Values that consolidate all three sampling sites. B. Yacayacá. C. Piracemo. D. Santa Cruz.
Fig. 4. Índice de Importancia Relativa (IIR) (%) de ítems alimenticios en peces Leporinus friderici muestreado desde los meses de marzo de 2014 a mayo de 2015. A. Valores consolidando los tres sitios de muestreo. B. Yacayacá. C. Piracemo. D. Santa Cruz. Fig. 4. Relative importance index (IIR) (%) of food items Leporinus friderici fish sampled from the months of March 2014 to May 2015. A. Values that consolidate all three sampling sites. B. Yacayacá. C. Piracemo. D. Santa Cruz.
Fig. 5. Análisis de cluster jerárquico de Bray-Curtis y MDS con base en el contenido estomacal de peces Leporinus friderici muestreados desde marzo 2014 a mayo 2015. A. Similitud superior al 60 %; B. MDS mostrando el agrupamiento dentro de 2 grupos cada uno con similitudes en sus ítems alimenticios. Asc: aguas ascendentes, Alta: aguas altas, Desc: aguas descendentes, Baja: Aguas bajas. Fig. 5. Hierarchical cluster analysis (Bray-Curtis) and MDS based on stomach content of Leporinus friderici sampled during the months of March 2014 to May 2015. A. Similarity higher than 60 %; B. MDS showing grouping between two groups each one with similarities in the feeding items. Asc: ascending water level, High: high water level, Desc: descending water levels, Low: low water levels.
Hábitos alimenticios de Leporinus friderici (Anostomidae, Teleostei) durante un ciclo hidrobiológico en el río Vaupés, Colombia

June 2017

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893 Reads

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3 Citations

Revista de Biologia Tropical

The most important fish species of the Vaupes River is known as a Warakú tres puntos (Leporinus friderici), the most representative migratory Characidae from the Vaupés state, Colombia, with a significant importance in food security of indigenous communities. To contribute with the knowledge of its basic biology, we determined the habits and food preferences of Leporinus friderici, during one hydrobiological cycle (March 2014 to May 2015) in the Vaupés River, Colombia. Three sites were sampled, two of them along the Vaupés river (Yacayacá and Santa Cruz communities) and the other one in the Cuduyarí river, tributary of the Vaupés river (Piracemo community). Physical and chemical water parameters from the surface and depth level of the river were determined. Stomach contents from 316 fish were analyzed by frequency of occurrence (FO), gravimetric index, vacuity index (VI) and relative importance index (RII). Vaupés’s average depth in ascending water period was of 3.7 ± 0.6 m, during rainy season of 5.9 ± 1.4 m, in descending water period of 4.6 ± 1.3 m and during dry season of 2.4 ± 1.0 m. The higher acidity and turbidity were observed during the ascending water period. The average VI was 14.5 % for the period, but it reached 40 % in descending waters. In general, a FO of plant material was the most frequent (44.4-66.7 %), followed by insects (21.1-33.3 %, secondary diets). The gravimetric indices showed that plant material was the most consumed item, followed by insects, and in almost in equal proportion, invertebrates and animal material were also observed. The differences in diet composition confirm the opportunistic nature of this species with a predominance of omnivorous habits. This study can be used as an integral part of the feeding ecology of L. friderici knowledge, in order to develop strategies for its protection in the Vaupés region because of its importance for local communities.


Hibridización de silúridos: una alternativa para la piscicultura con alto riesgo para la conservación de las especies nativas

July 2016

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198 Reads

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7 Citations

Revista Orinoquia

El propósito de este artículo es analizar, desde una mirada crítica, el riesgo a que se ven expuestas ciertas especies de silúridos, sometidas a procesos de hibridación por razones estrictamente comerciales, incluyendo los efectos sobre el hábitat, la competencia y la erosión genética. Es fácil comprender que dichos procedimientos tendrán en el futuro serios efectos sobre los recursos hidrobiológicos, los servicios ecosistémicos y la seguridad alimentaria, los cuales sólo pueden ser medidos a través del tiempo y no de forma inmediata.Palabras clave: Acuicultura; fitness; erosión genética; peces nativos; recursos acuáticos; Aquaculture; fitness; genetic erosion; native fish; aquatic resources


Figura 1. Sistema cerrado de circulación del agua: A. Vista lateral, B. Detalle de los contenedores.
The effect of rearing density on body weight and survival of larval stripped catfish (Pseudoplatystoma sp) into a closed circulating system

June 2016

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42 Reads

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1 Citation

Revista Orinoquia

In order to evaluate the effects of larval density rearing on body weight and survival of larvae of striped catfish (Pseudoplatystoma sp), was designed and built a closed recirculation system, which allowed maintaining stable physical and chemical variables of water throughout the experimental period. For this purpose, vitelline larvae were rearing in three densities: 10 (T1), 50 (T2) and 100 (T3) larvae per liter and monitored until 20 days post-hatch. They were evaluated four replicates per treatment, kept under photoperiod 0:24 (light: dark) and fed to apparent satiety with Artemia saline hatchlings, which were supplied divided into five portions a day: at 07:00, 09: 00, 14:00, 18:00 and 22:00 hours. The water quality characteristics observed during the test were: dissolved oxygen 5.7 ± 0.5 mg/L; temperature 26 ± 0.8 ° C; pH 7.6 ± 0.2; hardness 38.2 ± 5.2 mgCaCO3/L; alkalinity 26.5 ± 5.2 mg CaCO3 / L; NH3


Hybridization Silurids: An alternative for fish farming at high risk for the conservation of native species

June 2016

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16 Reads

Revista Orinoquia

The purpose of this article was to analyze, from a critical perspective, the risk that would be exposed some silurid species in captivity, subjected to hybridization processes for strictly commercial reasons, including habitat effects, competition and genetic erosion. It is easy to understand that these procedures will be in the future effects on aquatic resources, ecosystem services and food security, which can only be measured over time and not immediately.


Figura 3. Número de casos de patologías infecciosas agrupadas de acuerdo con el sistema afectado (***Chi-2, P<0.01). 
Figura 4. Número de casos de patologías no infecciosas agrupadas de acuerdo con la clasificación patológica 
Figura 5. Número de casos de patologías neoplásicas agrupadas de acuerdo al orígen. 
A retrospective study of pathological findings in wild and captive-wild animals in Villavicencio, Colombia

June 2015

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73 Reads

Revista Orinoquia

The present work is a first retrospective study of histopathological findings in wild animals samples received at the Histopathology Laboratory of the School of Veterinary Medicine, University of the Llanos, Villavicencio (Colombia), between 2004 and 2011. 43 cases were analyzed, mainly consisting of parasitic infections, neoplasia and necrotic and inflammatory reactions. Sixty-two percent (n = 31) were free life animals and 28% (n = 12) were from captivity. Most of these animals were mammals, who presented the highest annual rate (Chi-2, P


Citations (5)


... Milt cryopreservation in fish has been tried for different species, especially those of commercial and/or environmental interest [125][126][127][128][129][130][131]. When using cryopreserved milt from Brycon insignis (Characiformes), sperm motility of cryopreserved milt was 54% compared to 100% in fresh milt. ...

Reference:

Influence of Dietary Fatty Acids on Fish Sperm Tolerance to Cryopreservation
Cryostorage of white cachama (Piaractus orinoquensis) sperm: Effects on cellular, biochemical and ultrastructural parameters

Aquaculture Reports

... That means that migration is not a prerequisite for the spawning of landlocked populations of this species. Furthermore, hormonal induction was not necessary as indicated for some migratory fish [44,45]. Probably, the spawning in this species is mainly mediated by environmental conditions, such as photoperiod, water temperature, and substrate. ...

Cryopreservation of coporo (Prochilodus mariae) milt using three permeating cryoprotectant agents and two freezing systems
  • Citing Article
  • August 2021

... En tanto, estudios morfológicos gonadal en P. metaense x L. marmoratus, han demostrado que machos mayores a un año y medio de edad presentaron desarrollo testicular intermedio comparado con sus parentales; y, de manera contraria, las hembras presentaron maduración gonadal y desarrollo de ovocitos, lo que coincide con la época de mayor precipitación (junio y julio) (23). No obstante, faltarían estudios que permitan determinar el grado de correlación entre los niveles de cortisol y el desarrollo gonadal del híbrido P. metaense x L. marmoratus. ...

Gonadal Maturation in Pseudoplatystoma metaense x Leiarius marmoratus Hybrids, (Siluriformes: Pimelodidae)

International Journal of Morphology

... Pimelodid species, like most fish species, stand out for their phenotypic plasticity, which allows the application of artificial hybridization techniques in search of heterosis or hybrid vigor. Heterosis optimizes aquaculture production with faster growth rates, resistance to diseases, high food conversion ratio, and adaptation to feed concentrate (Hashimoto et al. 2012a;Rodríguez-Pulido et al. 2016). However, the development of a new hybrid with high possibilities of incorporation into productive chains represents a potential risk for native and wild species. ...

Hibridización de silúridos: una alternativa para la piscicultura con alto riesgo para la conservación de las especies nativas

Revista Orinoquia

... Se estima que anualmente se comercializan en Colombia cerca de 25 millones de PO, de los cuales el 88 % de los peces comercializados provienen de la cuenca de la Orinoquía, el 10 % de la cuenca Amazónica, el 1,7 % de la cuenca del Pacífico y el 0,3 % de la cuenca del Magdalena (Mancera-Rodríguez & Álvarez-León, 2008;Prada-Pedreros et al., 2009;Zúñiga, 2010), Estudios reportados por Sánchez et al. (2015), reconocen 16 áreas de pesca de peces ornamentales en el país; en la cuenca del río Orinoco: Villavicencio, Puerto Gaitán, Arauca, Puerto Carreño, Inírida, San José del Guaviare y Cumaribo; en la cuenca del río Amazonas: Puerto Leguízamo, Caquetá, La Pedrera, Leticia-Tarapacá; en la cuenca Magdalena-Cauca, entre Neiva y Honda, y Barranquilla (embalse del Guájaro y alrededores); en la cuenca del río Catatumbo: la subcuenca baja del río Zulia; en el Pacífico: zonas estuarinas de Buenaventura y Tumaco. La productividad de estas áreas de pesca está determinada por los ciclos de aguas bajas dados entre enero y marzo, aguas ascendentes entre abril y mayo, aguas altas entre junio y octubre y aguas descendentes entre noviembre y diciembre (Velasco-Santamaría et al., 2017). ...

Hábitos alimenticios de Leporinus friderici (Anostomidae, Teleostei) durante un ciclo hidrobiológico en el río Vaupés, Colombia

Revista de Biologia Tropical