Determination of field capacity in the Chibunga and Guano rivers micro-basins.

Background: The micro-basins of the Chibunga and Guano rivers are located within the sub-basin of the Chambo River, which starts at the thaw of the Chimborazo, crosses the cities of Guano and Riobamba, and ends in the Chambo River. These rivers are considered fluvial hydrological forces and geological limits of the aquifer, located in this sub-basin. For this reason, our investigation addressed the field capacity in the micro-basins of Chibunga and Guano rivers, to determine the maximum retention potential, i.e., the saturation of water in the soil. Methods: We investigated the change of precipitation to runoff through the correlations between the characteristics of the soil and its vegetation. We applied the Curve Number (CN) method introduced by the United States Soil Conservation Service (USSCS); this represents an empirical model, which relates the vegetation cover to the geological and topographic conditions of the soil. Along with the geographic information system, the model allows to represent the variation of runoffs for each micro-basin, according to the different land use categories, over the time frame from 2010 to 2014. Results: We found that the maximum retention potential is directly affected by CN values, representing the runoff potential. Highest values of 100 belong to the wetlands, urban area, snow, and water, as rain is converted directly into runoff, being impervious areas. The Guano river micro-basin possesses clay soil with CN of 78, the soil texture for eucalyptus forest is clay loam, and its CN value, 46, is the lowest of the data set. Knowledge of field capacity allows to properly evaluate the storage capacity of soil and water conservation. Conclusions: Results of this work will be useful in the quantification of the water balance, to determine the water supply and demand.

Differences in the ratio of soil microbial biomass carbon (MBC) and soil organic carbon (SOC) at various altitudes of Hyperalic Alisol in the Amazon region of Ecuador.

Protecting soil fertility represents a fundamental effort of sustainable development. In this study we investigate how different altitudes affect soil microbial biomass carbon (MBC) and soil organic carbon (SOC), and their ratio, MBC/SOC in Hyperalic Alisol. MBC and SOC are well established and widely accepted microbial quotients in soil science. Our work hypothesis was that a decrease in MBC and SOC should be observed at higher altitudes. This initial assumption has been verified by our measurements, being attributed to the increase in MBC and SOC at low altitudes. Our approach should contribute to the better understanding of MBC and SOC distribution in soil and changes in MBC/SOC at various altitudes in the region.

Effect of Extender and Freezing Rate on Quality Parameters and In Vitro Fertilization Capacity of Alpaca Spermatozoa Recovered from Cauda Epididymis.

In alpacas, improvement of reproductive efficiency of male camelids is limited by the small testicular size, low spermatozoa production, and low quality of semen. In this study we aim to evaluate the effect of two extenders and two freezing rates on post-thaw quality of sperm recovered from alpaca epididymis with two methods (flushing and mincing), and to evaluate the in vitro fertilization (IVF) capacity of frozen sperm selected with two different selection methods (washing and swim-up). Sperm samples were processed with Tris-egg yolk or Bioxcell® extenders and frozen with slow freezing and fast freezing. The oocytes were coincubated with spermatozoa for 72 hours, and cleavage rates were recorded afterward. The results indicated that the recovery method did not influence sperm quality (∼70%). However, total sperm recovery was significantly lower for the flushing method than the mincing method. The sperm quality was influenced by the freezing extender (23.3% vs. 33.2%) and freezing rate (20.9% vs. 35.7%). When comparing different methods of sperm selection for IVF, no differences were observed on cleavage rate except for the fact that the concentration of sperm from swim-up method (20.6%) was significantly lower than the one obtained from the washing method (78.7%). The recovery technique of sperm does not affect sperm quality and the method of fast freezing was shown to be the most effective for cryopreservation of alpaca sperm.

Activación química de ovocitos de alpaca vitrificados después de la maduración in vitro / Chemical activation of alpaca oocytes vitrified after in vitro maturation

Se evaluó la viabilidad posdescongelamiento de ovocitos de alpaca vitrificados luego de la maduración in vitro. Los ovocitos fueron recuperados de ovarios obtenidos en el camal Municipal de Huancavelica, Perú, madurados in vitro por 24-25 h en una cámara modular con 5% de O2, 5% de CO2 y 90% de N2 en medio TCM-199 suplementado con Piruvato de Na, HEPES, sulfato de gentamicina, FSH, estradiol 17-beta y suero fetal bovino. Los ovocitos fueron separados de las células de la granulosa con hialuronidasa al 0.1% y distribuidos en tres tratamientos: T1 (n=107), ovocitos expuestos a las soluciones crioprotectoras y vitrificados; T2 (n=121), ovocitos expuestos a las soluciones crioprotectoras no vitrificados (control de toxicidad de los crioprotectantes); T3 (n=232), grupo control de ovocitos no expuestos a las soluciones vitrificantes. Los ovocitos fueron vitrificados en microgotas sobre un papel de aluminio flotando en nitrógeno líquido, utilizando una solución de equilibrio con 4% de etilenglicol y una solución de vitrificación con 35% de etilenglicol, 5% de polivinilpirrolidona y 0.4 M de trehalosa. Las microgotas vitrificadas se almacenaron en nitrógeno líquido y fueron descongeladas 1-4 después. Todos los ovocitos fueron cultivados en SOF-HEPES con 5 uM de ionomicina de Ca por 4 min a temperatura ambiente y luego cultivados por 3 h en 6-DMAP a 38.5 °C en una atmósfera húmeda con 5% de O2, 5% de CO2 y 90% de N2. Luego se cultivaron por 8 d en medio SOF-IVC. Se encontró 58.4, 68.7 y 97.3% de ovocitos morfológicamente normales para T1, T2 y T3, respectivamente. Las tasas de segmentación fueron de 39.9, 49.5 y 62.3%, y las tasas de blastocistos fueron de 0, 0 y 9.2% para T1, T2 y T3, respectivamente. Los resultados demuestran que los ovocitos de alpaca pueden ser vitrificados con el método de superficie sólida y que son viables morfológicamente y fisiológicamente posdescongelamiento.

The aim of this study was to evaluate the viability of vitrified/thawed alpaca oocytes after in vitro maturation. Alpaca oocytes were retrieved from ovaries obtained in theslaughterhouse of Huancavelica, Peru and matured in vitro for 24-25 h in a modular chamber with 5% O2, 5% CO2 and 90% N2 in TCM-199 medium supplemented with sodium pyruvate, HEPES, gentamycin sulphate, FSH, estradiol 17-beta and fetal calf serum. Then, oocytes were fully denuded of cumulus cells with 0.1% hyaluronidase and assigned to three treatments: T1 (n=107), oocytes exposed to cryoprotectans and vitrified; T2 (n=121), oocytes exposed to cryoprotectans without vitrification; and T3 (n=232), control group of oocytes not exposed to vitrification solutions. Alpaca oocytes were vitrified in microdrops on a precooled aluminum foil floating in liquid nitrogen, using an equilibrium solution with 4% ethylene glycol and a vitrification solution with 35% ethylene glycol, 5% polyvinyl-pyrrolidone and 0.4 M trehalose. The vitrified microdrops were stored in liquid nitrogen and were thawed 1-4 d later. All oocytes were cultured on SOF-HEPES with 5 umM Ca ionomycin by 4 min at room temperature followed by 3 h incubation in 6-DMAP at 38.5 ºC in a 5% O2, 5% CO2 and 90% N2 in humidified atmosphere. Subsequently, were cultivated on mSOF medium during 8 days. The rates of oocytes survival were 58.4, 68.7 and 97.3% in T1, T2 and T2 respectively. The rates of cleavage were 39.9, 49.5 and 62.3% and rates of development to blastocysts were 0, 0 and 9.2% in T1, T2 and T3 respectively. The results showed that alpaca oocytes were morphologically and physiologically viable after vitrification by solid surface method.