Maritza Pérez Atehortúa

The reproduction of some fish species in captivity is only possible by imposing artificial reproductive procedures, and the manipulation of fish for these purposes is a stressor. Thus, anesthesia can reduce stress during handling. However, it is necessary to investigate the possible side effects on breeding and the general health of the animal. Therefore, we aimed to investigate the impact of tricaine methanesulfonate (MS-222) and eugenol (EUG) at concentrations of 300 mg L-1 and 40 mg L-1, respectively, on several stress- and reproductive-related parameters in Rhamdia quelen anesthetized before semen collection. After hormonal induction, 24 sexually mature males (534.4 ± 259 g) were randomly assigned to treatment groups and semen and blood samples were collected. Anesthesia recovery and induction time were extended in fish anesthetized with EUG; however, plasma cortisol concentrations did not differ among the treatment groups. EUG caused higher DNA fragmentation in blood cells than in the control group (without anesthesia). EUG increased the monocyte count compared to the other experimental groups. MS-222 showed a lower sulfhydryl group (SH) quantitation than the other experimental groups. The anesthetics used before semen collection in this study had no adverse effects on the fertilization or hatching capacity of anesthetized R. quelen. MS-222 (300 mg L-1) and EUG (40 mg L-1), despite being related to hematological and semen changes, did not negatively affect the reproductive capacity of R. quelen males. Thus, anesthesia is recommended for R. quelen during semen collection, considering reproductive parameters and animal welfare.

We investigated the impact of weaning at 30, 75, and 180 days of age on performance, body measurements, and rumen development (using the β-hydroxybutyrate biomarker) of beef calves until 190 days of age. A total of 64 Brangus calves were assigned to three treatments: hyper-early (W30), weaned at 32±0.89 days of age (n = 22, 10 males and 12 females); early (W75), weaned at 77±0.95 days of age (n = 20, 12 males and eight females); and conventional (W180), [...] ABSTRACT We investigated the impact of weaning at 30, 75, and 180 days of age on performance, body measurements, and rumen development (using the β-hydroxybutyrate biomarker) of beef calves until 190 days of age. A total of 64 Brangus calves were assigned to three treatments: hyper-early (W30), weaned at 32±0.89 days of age (n = 22, 10 males and 12 females); early (W75), weaned at 77±0.95 days of age (n = 20, 12 males and eight females); and conventional (W180),

This study determines the reproductive patterns of puye (Galaxias maculatus) under culture conditions. A population of 567 wild fish was caught in the Cautín River, Chile, and held in captivity for four years. Mortality, sex ratio, gonadosomatic index (GSI), sexual maturity stages, spawning period, type and frequency of spawning, and fecundity were measured. The fish grew throughout the experimental period, with the fastest rate during the first half of the first year of life. The highest mortality occurred during the first three months of the experiment and during the spawning season. The sex ratio was almost 1:1 (female:male). First sexual maturity was reached at one year of age, with an average weight of 0.85 ± 0.01 g, total length of 4.85 ± 0.16 cm, and condition factor 0.0074. The highest GSI in both females (12.14 ± 0.74) and males (17.7 ± 2.70) was recorded in August. Nevertheless, the females spawned 3 to 10 times between September and February, with the highest reproductive peak between September and October. The number of embryos per female per day varied from 1 to 429, while the total number of embryos per female during the entire season evaluated varied from 163 to 1044. There was a high correlation (r = 0.82) between absolute fecundity and body weight. Although further studies are needed in this field, these results are basic for establishing future reproductive programs in captivity as a strategy for sustainable fisheries and aquaculture management.

: In brief: The containers used in cell cryopreservation are essential to maintain cell integrity and viability after thawing. This paper reveals the methodology of using biodegradable containers for fish sperm cryopreservation. Cryopreserved sperm in biodegradable containers showed high fertility capability. Biodegradable capsules could be alternative containers to plastic straws for sperm cryopreservation. Containers used to cryopreserve sperm are made with non-biodegradable plastic compounds, having a high monetary and environmental cost. Therefore, the development of biodegradable alternative containers for cell cryopreservation is necessary. Thus, this study aimed to evaluate the efficiency of hard-gelatin and hard-hydroxypropyl methylcellulose (HPMC) capsules as low-cost and biodegradable alternative containers for sperm cryopreservation. Sperm from 12South American silver catfish Rhamdia quelen were individually cryopreserved in plastic straws 0.25 mL (as control), hard-gelatin, and hard-HPMC capsules. The quality of post-thaw sperm cryopreserved in the different containers was checked by measuring spermatozoa membrane integrity, kinetic parameters, mitochondrial activity, fertilization, hatching, and normal larvae rates. The samples cryopreserved in straws showed a higher percentage of membrane integrity (68%) than those frozen in hard-gelatin (40%) and hard-HPMC capsules (40%). However, we did not observe differences between the samples stored in straws and hard capsules for the rest of the tested sperm parameters. Thus, based on the high sperm fertility capability, both capsules were efficient as cryopreservation containers for maintaining sperm functionality.

La hierba kikuyu es una planta con alto potencial para integrar carbono en materia orgánica porque utiliza la ruta fotosintética C4, se cree que esta hierba tiene la capacidad de contribuir a la mitigación del calentamiento global. Esto es posible, bajo buenas prácticas de manejo tanto durante el pastoreo como en el período de recuperación de los pastizales. El objetivo del trabajo fue identificar las reservas de carbono en el pasto kikuyu ( Cenchrus clandestinus).(ex Hochst. Chiov.) Morrone) en sus diferentes compartimentos, biomasa aérea (AB) (hojas, tallos y tallos rastreros) y biomasa subterránea (BB) (raíces finas y raíces gruesas o "Stolons") a 20 y 40 cm de profundidad del suelo. Se realizaron seis muestreos sucesivos de acuerdo con el período de descanso del pasto, el sistema de pastoreo (sistema tradicional y silvopastoril) y de acuerdo con la geoforma del terreno (flanco cóncavo (CCF), flanco convexo (CXF), flanco rectilíneo (RF) y relieve plano (FR)). La biomasa aérea se muestreó con cuadros de medición y la biomasa subterránea se muestreó con barrena de raíz. Este experimento se llevó a cabo entre junio de 2016 y junio de 2017 en San Pedro de los Milagros, Antioquia, Colombia. Los resultados obtenidos nos permitieron determinar que las raíces stoloniferous a 20 cm de profundidad, los tallos rastreros muertos y las hojas fueron los compartimentos con las mayores reservas de carbono, que contenían 4,52, 3,58 y 1,9 toneladas de C ha-1, respectivamente. Se encontraron diferencias significativas (p <0.05) entre el relieve plano y las geoformas de flanco rectilíneo para la biomasa de las hojas, y entre el relieve plano y los otros relieves evaluados para las raíces gruesas variables a 20 cm de profundidad. Concluimos que la hierba kikuyu contribuye a mantener reservas de carbono en los pastos. La biomasa producida en cada compartimento por la planta es proporcional al carbono incorporado. La biomasa para raíces finas y gruesas contribuye a la captura de carbono, se obtuvieron alrededor de 2820 kg y 655 kg de carbono por hectárea a profundidades de 20 y 40 cm respectivamente. Debido a la alta producción de biomasa subterránea, de tallos rastreros y su alta capacidad de rebrote bajo condiciones adversas, la hierba kikuyu puede ayudar a reducir la erosión de los suelos de las laderas y mejorar la contribución del carbono al aportar 3.475 kg de carbono por hectárea a 40 cm de profundidad. Lo anterior indica que juega un papel importante en la mitigación de los gases de efecto invernadero, ayudando a conservar los suelos tropicales altos en sistemas de producción de lácteos especializados.