Scientia Agropecuaria

Molecular characterization of native colored cotton varieties on the north coast of Peru

Effect of smoking and fat content on the dynamic perception of bacon by Brazilian consumers

The high heterogeneity of meat and meat products can influence the sensory perception of the consumers, being necessary to measure the real impact of these non-controllable variables on the dynamic sensory properties of the smoked bacon during tasting. The aim of this study was to evaluate the effect of smoking and fat content on the dynamic sensory perception of bacon by Brazilian consumers. For this, four different samples were prepared, varying the fat content (from "low" to "high") and the type of smoking shown on the product label (natural and artificial). Thirty-five habitual smoked bacon consumers evaluated the dynamic sensory properties of the product using the Temporal Dominance of Sensations (TDS) method. The results were submitted to univariate (bandplot by attribute) and multivariate analyzes (Principal Component Analysis) to study both the dominance rate and its duration, respectively. The main attributes modified during tasting were "salty," "fatty," and "succulent," thus showing that the dynamic sensory perception of smoked bacon was modified by the type of smoking and the fat content of the sample.

Quantification of total polyphenols and antioxidant capacity in skins and seeds from cacao (Theobroma cacao L.), tuna (Opuntia ficus indica Mill), grape (Vitis Vinífera) and uvilla (Pourouma cecropiifolia)

Los objetivos fueron cuantificar los polifenoles totales y la capacidad antioxidante mediante la inhibición de los radicales DPPH y ABTSº+ en cáscara y semilla de tuna, cacao, uva y uvilla . Las muestras fueron secadas a 60 °C/12 h y molidas, se preparó un extracto agua/metanol (v/v) se maceró por 24 h y centrifugó a 10000 rpm/10min/4 ºC. Los resultados fueron analizados mediante el diseño completo al azar (DCA) y un análisis multivariado. El contenido de polifenoles varió entre 9,07 a 1,78 g EAG/100g. La capacidad antioxidante frente al radical DPPH tuvo el siguiente orden: Semilla de uva, piel y semilla de uvilla> piel de uva y cascarilla de cacao>cáscara de cacao>cáscara de tuna morada> semilla de tuna amarilla> piel de tuna amarilla> cáscara de tuna amarilla > piel de tuna morada > semilla de tuna morada. La correlación entre polifenoles totales y la eficiencia de la actividad antioxidante (DPPH), fue r2 = 0,934. La mayor capacidad antioxidante frente al radical ABTSº+ se encontró en piel y semilla de uvilla, semilla de uva, y la menor en cáscara tuna amarilla. Según el análisis de componentes principales los mejores tratamientos fueron la piel y semilla de uvilla y semilla de uva.

The objectives were to quantify the total polyphenols and the antioxidant capacity by inhibiting the DPPH and ABTSº+ radicals in skins/peel and seed of tuna, cocoa, grape and uvilla. The samples were dried at 60 °C/12 h and ground; an extract water/methanol (v/v) was prepared; it was macerated for 24 hours and then centrifuged at 10000 rpm/10 min/4 ºC. The results were analyzed using the completely randomized design (CRD; DCA - acronym in Spanish) and a multivariate analysis. The content of the polyphenols varied between 9.07 and 1.78 gEAG/100g. The antioxidant capacity against the DPPH free radical had the following order: grape seed, cape gooseberry skin and seed > grape skin and cacao skin > cacao hull > purple prickly pear peel > yellow prickly pear seed > yellow prickly pea r skin > yellow prickly pear peel > purple prickly pear skin > purple prickly pear seed. The correlation between total polyphenols and the antioxidant activity (DPPH) efficiency was r2 = 0.934. The greatest antioxidant capacity against the ABTSº+ free radical was found in the cape gooseberry skin and seed and the grape seed; the least was found in the yellow prickly pear peel. According to the principal component analysis, the best treatments were the cape gooseberry skin and seed and the grape seed .

Inhibitory action of dried leaf of Cassia alata (Linn.) Roxb against lipoxygenase activity and nitric oxide generation

The mechanisms of inflammation mediated by metabolites of lipoxygenase and nitric oxide play essential roles in physiological immune response. The aim of this study was to evaluate the lipoxygenase (LOX) inhibitory activity of methanolic extract of dried leaf of Cassia alata (Linn.) Roxb. as well as its effect on in vitro accumulation of nitric oxide (NO). The LOX inhibitory activity was evaluated for its ability to inhibit lipoxygenase (soyLOX) by absorbance-based assay using linoleic acid as the substrate while the influence of the extract on accumulation of NO was monitored spectrophotometrically by Griess assay method. Moreover, gas chromatographic analysis was carried out on the ether extract to identify and quantify the volatile compounds in the extract. The study showed effective soyLOX inhibitory activity correlating with the NO depletion in a concentration- dependent manner. The gas chromatographic identification of the volatile compounds in the extract showed the presence of stearic, oleic and linoleic acids. This study revealed the methanolic extract of the leaf of C. alata (Linn.) Roxb. as potent inhibitor of both soyLOX and nitric oxide generation. Thus, these results give indications regarding therapeutic interest of C. alata (Linn.) Robx. as a potential anti- inflammatory agent.

A diet based on Ulva lactuca flour improves growth fingerlings sea chub Girella laevifrons (Pisces: Kyphosidae)

El objetivo fue evaluar el uso del alga verde Ulva lactuca en el crecimiento de alevines de bauncos Girella laevifrons. Se emplearon tres dietas experimentales con niveles de inclusión del 15, 30 y 45% de harina de U. lactuca y una dieta control sin inclusión de harina de U. lactuca (0%). El ensayo duro 30 días y se realizó en grupos duplicados y se emplearon 120 alevines de peso medio de 0,458 ± 0,10 g, los cuales fueron distribuidos en 8 acuarios de vidrio a razón de 15 ejemplares por acuario. El mayor crecimiento en peso y longitud se obtuvo con 30% de inclusión de harina de U. lactuca, significativamente diferente (p < 0,05) del tratamiento con el 15% de inclusión de harina de U. lactuca. Este es el primer trabajo donde se ha investigado el uso de la macroalga U. lactuca en el crecimiento de esta especie y por tanto se recomienda realizar más trabajos de índole similar para poder determinar el potencial acuícola que tendría la misma.

The objective was to evaluate the use of green alga Ulva lactuca in the growth of fingerlings sea chub Girella laevifrons. Three experimental diets were used with inclusion levels of 15, 30 and 45% U. lactuca meal and a control diet without inclusion of U. lactuca meal (0%). The trial lasted 30 days and was carried out in duplicate groups and 120 fingerlings of average weight of 0.458 ± 0.10 g were used, which were distributed in 8 glass tanks at a rate of 15 specimens per aquarium. The highest growth in weight and length was obtained with 30% inclusion of U. lactuca meal, significantly different (p < 0.05) from the treatment with 15% inclusion of U. lactuca meal. This is the first work where the use of the macroalga U. lactuca has been investigated in the growth of this species and therefore it is recommended to perform more similar work in order to determine the aquaculture potential that it would have.

Antagonistic capacity of Trichoderma harzianum compared to Rhizotecnia, Nakataea sigmoidea, Sclerotium rolfsii and its effect in native strains of Trichoderma isolated form rice crops

Se ha estudiado la capacidad antagónica de una cepa comercial de Trichoderma harzianum, frente a Rhizoctonia spp., Nakatea sigmoide y Sclerotium rolfsii, causantes de la Pudrición de tallos y vainas del arroz, así como su efecto en 14 cepas nativas de Trichoderma aisladas de diferentes campos arroceros. La prueba in vitro demostró que T. harzianum presenta una elevada actividad antagónica e hiperparasítica contra Rhizoctonia. La mayor acción de micoparasitismo se presentó con Rhizoctonia, siendo muy frecuente el enrollamiento de hifas y la penetración; en Nakataea se observó sólo enrollamiento y, en Sclerotium no se observó enrollamiento. El desarrollo de la cepa de T. harzianum (comercial), no afecta a las cepas nativas de Trichoderma spp. ensayadas en este trabajo, en la mayoría de los casos, las cepas de Trichodermas nativos mostraron un rápido desarrollo entre las 48 y las 72 horas. Aun cuando las cepas de Trichoderma nativos mostraron un mayor desarrollo vegetativo, la cepa comercial de T. harzianum genera una mayor producción de conidias, con un incremento de 29,53% muy importante en la trasmisión y diseminación de estos antagonistas en el suelo.

It has studied the antagonistic capacity a commercial Trichoderma harzianianum, against a Rhizoctonia spp., Nakatea sigmoide y Sclerotium rolfsii, causing the rot of stems and pods of rice, as well as its effect on 14 native strains of Trichoderma isolated of different rice fields. The in vitro test showed that T. harzianum presents a high antagonistic activity and hyperparasitica against Rhizotocnia. The greater action of mycoparasitism arose with Rhizotocnia, being very frequent the curl of hyphae and penetration; in Nakataea, only curl was observed and no curl was observed in Sclerotium. The development of strain of T. harzianum (comercial) does not affect the native strains of Trichoderma spp. Tested in this work, in most cases, strains of Trichodermas native showed a rapid development between 48 and 72 hours. Although the strains of Trichoderma native showed a greater vegetative development, the strain comercial T. harzianum generates a higher production of conidia, with an increase of 29.53% very important in the transmission and dissemination of these antagonists in the soil.

Irrigation coefficients of turfgrass (Stenotaphrum secundatum) in arid conditions, under water stress using subsurface drip irrigation

El trabajo de investigación tuvo como objetivo obtener los coeficientes de riego del césped americano, se evaluaron 1,0; 0,8; 0,6 y 0,4 de la evapotranspiración potencial para cada estación durante un año. Las variables climáticas fueron monitoreadas por una estación automática y se utilizó el riego por goteo subterráneo, no se presentó intrusión de las raíces en los laterales de riego. Para el monitoreo de la distribución de humedad se utilizaron sensores TDR, obteniéndose coeficientes de uniformidad entre el 90 a 92 %. El monitoreo de la humedad en el tiempo y el estado energético se realizó mediante sensores FDR y curvas pF. La calidad visual fue evaluada mediante el color, uniformidad y cobertura, esta última apoyada en imágenes digitales. Se ensayaron diferentes coeficientes de riego para cada estación. Finalmente se seleccionaron los coeficientes que permitieron mantener al césped con bajo requerimiento de agua y mantenimiento, así como una buena calidad visual, aplicando el Proceso de Análisis Jerárquico. Los coeficientes seleccionados fueron: 0,8; 0,8; 0,4 y 0,6 de la ETo para la verano, otoño, invierno y primavera respectivamente, obteniendo con ellos una adecuada calidad visual y un ahorro del volumen agua del 31%.

The research work had the objective to obtain the irrigation coefficients of Saint Augustine turfgrass, were evaluated 1.0; 0.8; 0.6 and 0.4 of the potential evapotranspiration for each season during the year. Climatic variables were monitored by an automatic station and sub-surface drip irrigation was used, no intrusion of the roots into the irrigation hoses and drips. To monitor the moisture distribution, TDR sensors were used, a uniformity coefficient between 90 and 92% was obtained. Moisture monitoring during the time and energy status were used FDR sensors and pF curves. Visual quality was evaluated through color, uniformity and coverage, the last one supported by digital imag es. Different irrigation coefficients were presented for each season. Finally, the coefficients that allowed keeping the turfgrass with low water requirement and maintenance were selected, as well as a good visual quality by applying the Hierarchical Analysis Process, the coefficients selected were: 0.8; 0.8; 0.4 and 0.6 of the ETo for the summer, autumn, winter and spring respectively, obtaining an adequate visual quality and a water volume saving of 31%.

Microbiological indicators of tropical soils quality in ecosystems of the north-east area of Peru

Tropical soils withstand heavy pressure due to deforestation as a result of the change in land use, decreasing their quality. Traditionally, the quality of soil has been based on physical and chemical indicators; however, the biological ones can predict variations in the quality, in an early and effective way. In this research, the microbiological quality of soils from two ecosystems was evaluated, one from the Cumbaza Sub-Basin (CSB) and the other from Degraded Pastures at Cuñumbuque (DPC), both in San Martín, Peru. The physicochemical characteristics were studied and the microbial populations of Total Bacteria (TB), Sporulated Bacteria (SB), Total Fungi (TF), Actinobacteria (ACT), and parameters of microbial activity such as Basal Respiration (BR), Microbial Biomass (MB), Metabolic Quotient (qCO2) and Microbial Quotient (qMIC). According to the Principal Component Analysis (PCA), the soils of the CSB had on average a lower biological quality compared to the DPC soils. The PCA discriminated that the microbial populations of TB, SB, ACT and MB represented effective microbiological indicators to evaluate the quality of the soils, in this respect the soils of Shapumba, Chontal, Aucaloma and Vista Alegre are degraded and require the application of new technologies and public policies for their recovery.

Microbial enrichment vermicompost under two production system and its effects on radish (Raphanus sativus L.) production

Se evaluó la calidad de vermicompost resultante de excreta de vacuno bajo dos sistemas de producción a través de sus parámetros físico químicos y de su efecto sobre el crecimiento y el rendimiento de plantas de rábano (Rhaphanus sativus L) bajo condiciones de campo en la Universidad Nacional Agraria la Molina (UNALM), Lima, Perú. Se empleó un diseño de bloques completo al azar (DBCA) 12 tratamientos con tres repeticiones. El primer factor de estudio incluyó dos tipos de compost de vacuno, compostados bajo dos tratamientos (lavado e inoculado con microorganismos benéficos). Como segundo factor se empleó dos tipos de microorganismos (Bacillus sp., y microorganismos benéficos). Un tercer factor incluyó dos sistemas de producción de vermicompost (zanja y techo a dos aguas) empleando Eisenia foetida (40 días). Los vermicomposts procedentes del sistema zanja presentaron mayor descenso en salinidad, pH, relación C/N, contenido total de fósforo, potasio, sodio y mayor incremento en contenido de humedad, calcio, magnesio y sustancias húmicas. C/N indicó la estabilización del vermicompost. En el rendimiento del rábano el tratamiento MZM (compost inoculado con microorganismos benéficos del sistema zanja) alcanzó mayor altura y peso fresco de hojas y peso de hipocótilo.

Vermicompost production from livestock manure was evaluated under two production systems through their chemical parameters and evaluating its effect on the growth and yield of radish (Rhaphanus sativus L.) under field condition at the National Agrarian University La Molina, in Li ma - Perú. The experimental design was a complete randomized block design (CRBD) with 12 treatments and three replications. The first factor of study includes two different types of livestock manure that was pre-decomposed under two treatments (washing and inoculation with beneficial microorganism consortium). As second factor, included two kinds of microorganism (Bacillus sp., and beneficial microorganism’s consortium). The third factor included two vermicomposting production system (superficial named "gable roof" and underground "pit system’’) processed with Eisenia foetida during 40 days. The characterization of vermicomposts from the pit system presented greater reduction in salinity, pH, C/N, total phosphorus, potassium, sodium concentration, higher retained moisture, total calcium, magnesium and humic subtances concentration. The C/N value showed that the vermicompost was stable. By comparison, the means indicate that treatment MMZ (livestock manure pre-decomposed inoculate with beneficial microorganism under pit system) attained greater height and length of leaves and individual weight of fruit.

Doses and splitting of nitrogen in two sowing densities of the flint yellow maize hybrid

Fue realizado un experimento con el objetivo de evaluar el efecto de diferentes densidades de siembra (62 500 y 69 444 plantas ha-1), dosis de nitrógeno (180, 200 y 220 kg ha-1) y su fraccionamiento (dos veces: estadios V3 (50%) y V7 (50%); y tres veces: estadios V3 (20%), V7 (40%) y V12 (40%)), sobre el desempeño agronómico del maíz amarillo duro ‘EXP-05’. El diseño experimental utilizado fue el de bloques completos al azar, en arreglo factorial 2x3x2, con cuatro repeticiones. No hubo efecto significativo de las interacciones de los factores sobre el crecimiento y componentes del rendimiento. Por otro lado, hubo efecto individual de las dosis de nitrógeno y de la densidad poblacional sobre el rendimiento en grano y diámetro de tallo, respectivamente. El mayor rendimiento en grano (10,639 t ha-1) fue obtenido con 200 kg ha-1 de N y el mayor diámetro de tallo (2,42 cm) con la menor densidad poblacional (62 500 plantas ha-1). A pesar que la interacción de los factores evaluados no fue significativa, el mayor rendimiento en grano (10,939 t ha-1) fue obtenido con 200 kg ha-1 de N, fraccionado en los estadios V3 (50%) y V7 (50%) y utilizando 69 444 plantas ha-1.

An experiment was conducted in La Molina, Lima, Peru, with the objective of evaluate the effect of planting densities (62 500 and 69 444 plants ha-1), nitrogen doses (180, 200 and 220 kg ha-1) and nitrogen splitting (two times: stages V3 (50%) and V7 (50%); and three times: stages V3 (20%), V7 (40%) and V12 (40%)), on the agronomic performance of the flint yellow corn hybrid EXP -05. The experiment used a completely random block design, in 2x3x2 factorial arrangement, with four replications. There was not significant effect of the interactions of the evaluated factors on growth and yield components. On the other hand, there was an individual effect of nitrogen doses and planting density on grain yield and stem diameter, respectively. The highest grain yield (10.639 t ha-1) was obtained with 200 kg ha-1 of N and the largest stem diameter (2.42 cm) with the lowest planting density (62 500 plant s ha-1). Although the interaction of the evaluated factors was not significant, the highest grain yield (10.939 t ha-1) was obtained with 200 kg ha-1 of N, splitting in two stages which are V3 (50%) and V7 (50%) and using 69 444 plants ha-1.

Grazing pressure on forage availability of Brachiaria decumbens

El objetivo de esta investigación fue evaluar el efecto de dos presiones de pastoreo en la disponibilidad de forraje Brachiaria Decumbens. La investigación se llevó a cabo en la Subestación Experimental Quilichao, del Centro Internacional de Agricultura Tropical (CIAT), Cauca, Colombia. Se evaluaron ocho disponibilidades iniciales de 4 300, 4 400, 4 800, 4 900, 6 000, 7 200, 17 400 y 18 900 kg de MSV por hectárea a dos presiones iniciales de pastoreo: baja, 1000 PV/100 kg MSV y alta, 1500 kg PV/100 kg MSV. El diseño fue de bloques al azar, con cuatro réplicas. El área se dividió en 12 subparcelas por tratamiento y la disponibilidad de forraje se midió al inicio, a las 2, 4, 6, 22, 26, 30, 46, 54, 70, 74 y 96 h de pastoreo. Se utilizaron novillos comerciales de la raza cebú, con peso promedio de 350 kg. Los resultados muestran que existen diferencias estadísticas (p < 0,05) entre presiones iniciales de pastoreo alta y baja. En ese sentido se concluye que a mayor disponibilidad inicial se tendrá mayor porcentaje de área foliar y tallos, pero menor porcentaje de material muerto, sin embargo, la relación hoja tallo disminuye conforme incrementa la disponibilidad inicial.

The objective of this research was to evaluate the effect of two grazing pressures on the availability of Brachiaria Decumbens forage. The research was carried out at the Quilichao Experimental Substation, of the International Center for Tropical Agriculture (CIAT), Cauca, Colombia. Eight initial availabilities of 4 300, 4 400, 4 800, 4 900, 6 000, 7 200, 17 400 and 18 900 kg of MSV per hectare were evaluated two initial grazing pressures: low, 1000 PV / 100 kg MSV and high, 1500 kg PV / 100 kg MSV. The design was of random blocks, with four replicas. The area was divided into 12 subplots per treatment and forage availability was measured at the beginning, at 2, 4, 6, 22, 26, 30, 46, 54, 70, 74 and 96 h of grazing. Commercial bullocks of the zebu race were used, with an average weight of 350 kg. Results show that there are statistical differences (p < 0,05) between initial high and low grazing pressures. Therefore, it is concluded that, the higher the initial availability, the higher the percentage of leaf area and stems, but the lower percentage of dead material, however, the leaf stem ratio decreases as the initial availability increases.

Induction of somatic embryogenesis from foliar explants in three varieties of coffee

El objetivo de la investigación fue establecer un protocolo de inducción de embriogénesis somática en las variedades Castillo, Catuaí y Costa Rica 95. Se instaló un ensayo de desinfección de hojas y otro para la inducción de embriogénesis somática. En el primer ensayo se evaluó diferentes concentraciones de NaClO, tiempo de inmersión y uso de solución antioxidante. El tratamiento de desinfección con mejores resultados fue 2% de NaClO por 5 minutos. En el segundo ensayo, se evaluó el efecto de diferentes tipos y concentraciones de reguladores de crecimiento; las citoquininas BAP y KIN (2,0; 4,0 y 6,0 mg/L), la auxina 2,4-D (0,1; 0,5 y 1,0 mg/L) y la combinación 2,4-D (0,1; 0,5 o 1,0 mg/L) + KIN (1,5 mg/L). Se logró inducir embriogénesis somática, directa e indirecta, en un solo medio de cultivo a partir de la semana 7 de iniciado el ensayo. La tasa de embriogénesis somática alcanzó valores de 100% en las tres variedades en algunos tratamientos. El número promedio de embriones/explante fue de 21,62; 26,84 y 7,4 en las variedades Castillo, Catuaí y Costa Rica 95, respectivamente. De los resultados, se concluyó que los tratamientos con BAP, 2,4-D y 2,4-D+KIN inducen embriogénesis somática según la variedad de café.

The objective of the research was to establish a protocol of somatic embryogenesis induction in Castillo, Catuai and Costa Rica 95 coffee varieties. Two trials were installed, one for leaf disinfection and other for somatic embryogenesis induction. In the first experiment different concentrations of NaClO, immersion times and use of antioxidant solution were evaluated. The best disinfection treatment was 2% NaClO for 5 minutes. In the somatic embryogenesis induction, different types and concentrations of growth regulators were tested; three concentrations of BAP and KIN (2.0, 4.0 and 6.0 mg/L), three concentrations of 2,4-D (0.1, 0.5 and 1.0 mg/L) were tested including combinations 2,4-D (0.1, 0.5 or 1.0 mg/L) + KIN (1.5 mg/L). Direct and indirect somatic embryogenesis was induced in only one culture medium from seventh week. The somatic embryogenesis rate reached values of 100% in the three varieties in some treatments. The average number of embryos/explant was 21.62, 26.84 and 7.4 in Castillo, Catuaí and Costa Rica 95 varieties, respectively. From the results, it was concluded that treatments with BAP, 2,4-D and 2,4-D+KIN induce embryogenesis according to coffee variety.

Fenología y rendimiento de cuatro variedades de papa en el Altiplano peruano

El objetivo de este trabajo fue comparar cuatro variedades de papa (Subsp. andigenum Hawkes, S. curtilobum Juz et Buk, S. juzepczukii Buk, S. stenotomum Just et Buk) en términos de fenología y rendimiento en condiciones agroecológicas de la región altiplánica del Perú. Para ello, se evaluaron parámetros fenológicos (descripción del tubérculo, planta, hoja, flor, bayas, intensidad de floración y período vegetativo) y productivos (rendimiento y número de tubérculos). Siendo la muestra 40 plantas seleccionadas al azar, las cuales fueron sembradas en suelo franco arenoso, bajo un manejo agronómico tradicional y riego por gravedad. Se determinó que la Subsp. andigenum Hawkes tiene la mayor producción (número y peso) en relación con las variedades estudiadas. El período vegetativo tuvo una duración entre los 169 a 183 días. Se concluye que las variedades estudiadas, son especies de ciclo fenológico semitardío.

The objective of this work was to compare four varieties of potato (S. andigenum Hawkes, S. curtilobum Juz et Buk, S. juzepczukii Buk, S. stenotomum Just et Buk) in terms of phenology and yield under agroecological conditions of the Altiplano region. Peru. For this, phenological parameters were evaluated (description of the tuber, plant, leaf, flower, berries, flowering intensity and vegetative period) and productive (yield and number of tubers). The sample consists of 40 plants selected at random, which were planted in sandy loam soil, under traditional agronomic management and gravity irrigation. It was determined that the Ssp. andigenum Hawkes has the highest production (number and weight) in relation to the varieties studied. The vegetative period lasted between 169 to 183 days. It is concluded that the varieties studied are species of semi-late phenological cycle.

Effect of Stevia rebaudiana Bertonni Leaves powder on Lipid Profiles and Productive Parameters of Laying Hens

Eggs are sources of high nutritious value; however, their intake is associated with hypercholesterolemia in consumers. Stevia rebaudiana, among other properties, has a hypoglycemic and hypocholesterolemic effect in humans, rats and broilers chicken. The objectives of this research were to determine the effect of the inclusion of 0, 1, 2 and 3% of Stevia rebaudiana leaves powder in the diet on the lipid profile and productive parameters of Isa Brown hens. One hundred, 17-24 week old, Isa Brown laying hens were used and distributed in a completely randomized design with four treatments and five repetitions. The increase in the levels of powder from Stevia leaves decreased the cholesterol profile (p < 0.05), without changing other profiles and the productive parameters (p > 0.05). Additionally, the triglyceride profile and weight gain showed quadratic and negative linear tendencies, respectively associated with the increase of powder from Stevia leaves in the diet. It is concluded that the levels of cholesterol, triglycerides, final weight and total weight gain of Isa Brown laying hens has a tendency to decrease when the levels of powder from Stevia leaves is increased in the diet.

Obtaining a complementary DNA encoding a fructan 1-exohydrolase in yacón, Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson

El yacón es una planta asterácea originaria de los Andes que en los últimos años ha recibido especial atención por sus propiedades nutricionales y farmacológicas. Sus raíces almacenan fructanos de tipo inulina con bajo grado de polimerización, también llamados fructooligosacáridos (FOS). La pérdida de los FOS en las estructuras reservantes con la consecuente disminución de sus propiedades funcionales están relacionadas directamente con la actividad de la enzima fructanoexohidrolasa (FEH). Las plantas de yac ón fueron obtenidas de la estación experimental "Baños del Inca" perteneciente al Instituto Nacional de Innovación Agraria (INIA). Examinando cuatro métodos de extracción de RNA total a partir de las raíces reservantes, se obtuvo un mejor rendimiento y calidad con el método CTAB modificado. El juego de cebadores diseñados y la técnica de RT-PCR generaron fragmentos traslapados del gen feh, así como el extremo 3’ del ARNm. El ensamblaje de los fragmentos permitió determinar cerca del 80 por ciento de la secuencia del gen y la región no codificante del extremo 3’. La construcción del árbol filogenético mostró un alto grado de identidad de la secuencia con las 1-FEHs de: C. intybus (88,5 %), H. tuberosus (88,2 %), V. herbácea (86,5 %) y A. lappa (85 %)

Yacon (Smallanthus sonchifolius) is an asteraceous plant native to the Andes that in recent years has received special attention for its nutritional and pharmacological properties. Its roots store fructans of inulin type with low degree of polymerization, also called fructooligosaccharides (FOS). The loss of FOS in the yacon reserve structures and the consequent decrease of its functional properties are directly related to the hydrolytic activity of the enzyme fructanexohydrolase (FEH). Yacon plants were obtained from the "Baños del Inca" experimental station, belonging to the National Institute of Agrarian Innovation (INIA). By examining four methods of extracting total RNA from the storage roots, better performance and quality were obtained with the modified CTAB method the designed primer sets and the RT-PCR technique generated overlapping fragments of the feh gene, as well as the 3'-end of the mRNA. The assembly of the fragments allowed to determine about 80 percent of the gene sequence and a 3’untranslated region. Construction of the phylogenetic showed a high degree of identity of the sequence with the 1-FEHs of: C. intybus (88.5 %), H. tuberosus (88.2 %), V. herbacea 86.5 %) and A. lappa (85 %)

Effect of habitat change on the nutritional and functional characteristics of 16 quinoa (Chenopodium quinoa Willd.) accessions cultivated in the Peruvian Coast

El objetivo de la investigación fue evaluar el efecto del cambio de hábitat en algunas características nutricionales y funcionales de 16 accesiones de quinua con diferente contenido de saponinas, colectadas en la Sierra de Cuzco (promedio 3237 m.s.n.m.) y cultivadas en la Costa de Lima (235 m.s.n.m.) en Perú. Las quinuas se lavaron y secaron, para su posterior análisis. La cantidad promedio de proteínas (18,21±1,00%), cenizas (3,33±0,51%) y fibra dietaria Total (12,94±1,40%), de los cultivos de la Costa, fueron significativamente mayores (p value < α (0,05)), en comparación a sus homólogas originales de la Sierra (15,68±1,57%, 2,40±0,23% y 10,56±1,01%, respectivamente); mientras que la cantidad promedio de carbohidratos (69,74±1,32%), la digestibilidad de almidón in vitro (46,97±23,40%) y la digestibilidad de proteína in vitro (63,62 ±4,32%), fueron significativamente menores respecto las quinuas originales de la Sierra (72,19±3,01%, 59,16 ±23,94%, 67,21 ±6,28%, respectivamente). La humedad, grasa y fibra bruta, el contenido total de polifenoles y los niveles de capacidad antioxidante no mostraron cambios significativos. Se demuestra que el cambio de hábitat influye en algunas de las características nutricionales y funcionales en los granos de quinua.

The aim objective was evaluated the effect of habitat change on some nutritional and functional characteristics of 16 accessions of quinoa with different content of saponins, collected in the Sierra of Cuzco (3237 m.a.s.l.) and cultivated in the Coast of Lima (235 m.a.s.l.) in Peru was evaluated. Quinoas were washed, dried and ground, for further analysis. The average amount of proteins (18.21±1.00%), ashes (3.33±0.51%) and total dietary fiber (12.94±1.40%), of the crops of the Coast, were significantly higher (p value <α (0.05)), than their original homologs of the Sierra (15.68±1.57%, 2.40±0.23% and 10.56±1.01% , respectively); while the average amount of Carbohydrates (69.74±1.32%), in vitro starch digestibility levels (46.97±23.40%) and in vitro protein digestibility levels (63.62 ± 4.32%), were significantly lower than the original quinoas of the Sierra (72.19±3.01%, 59.16±23.94%, 67.21±6.28%, respectively). Fat, fiber, total polyphenol content and antioxidant capacity levels did not show significant changes when changing habitat. The habitat change is proved to be an influence on some nutritional and functional characteristics of the quinoa beans.

Botanical composition of a natural rangeland overseeded with annual ryegrass under N fertilization

The fertilization in rangelands has a positive effect in the forage production. The increased nitrogen (N) availability improves plant growth and forage quality of native pastures. However, in the Pampa biome conditions of Rio Grande do Sul State, Brazil, these responses occur surprisingly fast and consistently. Therefore, the objective of this work was to quantify the N effect in the botanical composition of a natural pasture overseeded with annual ryegrass in Southern Brazil. The effects of three rates of N fertilization (zero, 100 and 200 kg N ha-1) were evaluated. Forage biomass was estimated on a monthly basis using the double sampling approach. The different botanical components of each forage sample were manually sorted in the laboratory. In order to calculate the Rényi diversity profile, two floristic composition evaluations were performed in the experimental area in December of 2010 and September of 2011. The ryegrass biomass production is highly affected by the N fertilization. The botanical composition of natural pastures modifies most probably by increasing ryegrass competition at early spring.

Biochemical methane potential of chicken litter added with propionate in mesophilic conditions

El objetivo del trabajo fue determinar el potencial bioquímico de metano de pollinaza en combinación con una alta concentración de propionato, empleando un consorcio microbiano previamente adaptado a elevadas cantidades de este metabolito. La pollinaza al 3 % de sólidos totales (ST) con 4895 ppm de propionato fue degradada en condiciones mesofílicas empleando microcosmos con un volumen de trabajo de 250 mL. Los resultados del rendimiento de metano acumulado indicaron un comportamiento triple sigmoidal; lo cual podría atribuirse a la diferencia en las velocidades de degradación de los componentes, tales como macromoléculas y ácidos grasos volátiles. El potencial bioquímico de metano fue de 364,52 mL CH4 gSValimentados-1.

The objective of the work was to determine the biodegradability potential of chicken litter in combination with a high concentration of propionate, using a microbial consortium previously adapted to high amounts of this metabolite. The chicken litter 3 % of total solids (TS) with 4895 ppm of propionate was degraded under mesophilic conditions using microcosms with a working volume of 250 mL. The accumulated methane yield results indicated triple sigmoidal behavior; which could be attributed to the difference in the degradation rates of the components, such as macromolecules and volatile fatty acids. The biochemical potential of methane was 364,52 mL CH4 gVSfe -1.