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Chilean Journal of Agricultural & Animal Sciences
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  This is an Open Access Journal Open Access journal
ISSN (Print) 0719-3882 - ISSN (Online) 0719-3890
Published by SciELO Homepage  [672 journals]
  • CRECIMIENTO Y CALIDAD DE PLANTAS DE CAFÉ ARÁBICA CON LA APLICACIÓN DE
           BIOCHAR Y BIOFERTILIZANTES EN VIVERO

    • Abstract: ABSTRACT The physiological quality of seedlings in the nursery stage is essential to guarantee their adaptation and survival to post-transplant stress in the field. This study aimed to evaluate the effects of biochar and biofertilizers on the growth and quality of Coffea arábica cv. Sarchimor-1669 plants in the nursery. The evaluated treatments were: biochar (T1), biofertilizer (T2), biochar + biofertilizer (T3), chemical fertilization (T4), and a control (T5). Biochar was applied in doses of 20 g kg-1 in the substrate. The biofertilizer used was a native microbial consortium consisting of bacteria, mycorrhizae, fungi and yeasts, which was applied in doses of 5 mL L-1 using water. The main variables under study were: dry matter content (DMC), leaf area (LA), relative growth rate (RGR), net assimilation rate (NAR) and Dickson's quality index. The results showed significant differences (p<0.05) for all the variables evaluated. The treatments T1, T2, T3 and T4 were statistically similar, but they presented differences with respect to the control treatment. The biochar + biofertilizer mixture (T3) reached higher dry matter and leaf area per plant compared to the other treatments, with values of 8.28 g and 316.63 cm2, respectively. This treatment also recorded higher RGR, NAR and Dickson's quality index. The quality of the plants was positively correlated with the growth variables. It is concluded that the application of biochar and biofertilizer tends to enhance both growth and quality of coffee seedlings in the nursery. However, further research is required to evaluate higher doses and application frequencies in order to achieve conclusive results.RESUMEN La calidad fisiológica de plántulas en fase de vivero es un aspecto fundamental para garantizar la adaptación y sobrevivencia al estrés post-trasplante en campo definitivo. El objetivo de la investigación fue evaluar el efecto de biochar y biofertilizantes sobre el crecimiento y calidad de plantas de Coffea arábica cv. Sarchimor-1669 en vivero. Los tratamientos evaluados fueron: biochar (T1), biofertilizante (T2), biochar + biofertilizante (T3), fertilización química (T4) y un control (T5). El biochar fue colocado en dosis de 20 g kg-1 de sustrato. El biofertilizante utilizado fue un consorcio microbiano nativo compuesto de bacterias, micorrizas, hongos y levaduras, que fue colocado en dosis de 5 mL L-1 de agua. Las principales variables estudiadas fueron masa seca de planta (MS), área foliar (AF), tasa de crecimiento relativo (TCR), tasa de asimilación neta (TAN) e índice de calidad de Dickson. Los resultados mostraron diferencias significativas (p<0,05) para todas las variables evaluadas. Los tratamientos T1, T2, T3 y T4 fueron estadísticamente similares, pero mostraron diferencias con respecto al tratamiento control. La mezcla biochar + biofertilizante (T3) alcanzó mayor masa seca y área foliar por planta en relación a los demás tratamientos, con valores de 8,28 g y 316,63 cm2, respectivamente. Este tratamiento también presentó mayor TCR, TAN e índice de calidad de Dickson. La calidad de las plantas se correlacionó positivamente con las variables de crecimiento. Se concluye que la aplicación de biochar y biofertilizante tiende a potenciar el crecimiento y calidad de plántulas de café en vivero. Sin embargo, se require explorar mayores dosis y frecuencias de aplicación con fines de lograr resultados concluyentes.
       
  • COMPARISON OF THE NUTRITIONAL AND ANTIOXIDANT VALUES OF THE PERIPHERAL
           LAYERS IN TWO SPECIES OF WHEAT (SOFT AND HARD) GROWN IN ALGERIA

    • Abstract: ABSTRACT A study was carried out to determine the content of secondary metabolites and their antioxidant activity, and compare the chemical composition of the peripheral layers of two varieties of wheat, soft wheat (Triticum aestivum) Ziden and durum wheat (Triticum durum) Chen's, cultivated in the western region of Algeria. The infusion of the powder from the outer layers of both varieties was carried out with methanol. Antioxidant activity was evaluated by the DPPH (2,2-diphényl 1-picrylhydrazyle) and FRAP(fluorescence recovery after photo bleaching) methods. The phenolic compounds in the crude extracts of the two varieties were analyzed by HPLC. Contents of calcium, iron, magnesium, copper, and manganese were analyzed by atomic absorption spectrophotometry. The ethyl acetate extract (EC50 mg mL-1 = 0.24 ± 0.001) for Ziden (EC50 mg mL-1) = 0.03 ± 0.004) for Chen's showed antioxidant potential. Three phenolic acids were detected for the Chen's variety (Gallic acid, 4- (p)-hydroxybenzoic and Syringic acid), and a phenolic acid (Syringic acid) was detected for the Ziden variety. Protein determination by the Bradford method showed that the Chen's variety has a higher concentration of proteins (0.005 mg / mL), with a1.5%fiber content. Regarding mineral content, the most abundant element was calcium. Images of the peripheral surface layers of husked wheat grains obtained by scanning electron microscopy revealed almost similar structures for the two species. It can be concluded that Chen's (durum wheat) has more nutritional value than Ziden (durum wheat).
       
  • SUSTAINABILITY AND PRODUCTIVITY OF DIFFERENT CROP SEQUENCES UNDER TWO
           TECHNOLOGICAL MANAGEMENT PRACTICES IN THE PAMPEAN REGION OF ARGENTINA

    • Abstract: ABSTRACT According to FAO estimates, global food production needs to increase by 60% to feed the world's population in 2050. This increasing demand for food has led to agricultural intensification, which has strongly affected the structure and function of agroecosystems. The objective of this study was to evaluate productivity and sustainability of different crop sequences based on different indicators under two technological management practices (medium and high levels) in the Pampean Region, Argentina. The following indicators were evaluated: balances of nitrogen (N), phosphorous (P), carbon (C), and water use efficiency (WUE). Canola/ soybean (late-sown)-corn-sorghum-wheat was the sequence with the highest annual mean values of productivity (234 GJ ha-1), C balance (923 kg ha-1), and water use efficiency (9.60 kg ha-1 mm-1). However, it recorded the lowest negative annual balances of N (-138 kg ha-1) and P (-20 kg ha-1). Oat/soybean (late-sown)-corn-sunflower sequence had the lowest annual nutrient extractions, and thus the least negative annual nutrient balances of N (-81.75 kg ha-1) and P (-8.67 kg ha-1), also recording the lowest annual productivity (172 GJ ha-1) and WUE (7.99 kg ha-1 mm-1). Barley/soybean (late-sown)-corn-soybean- wheat and wheat/soybean (late-sown)-corn-soybean-wheat sequences had high productivity and contributed C to the soil, but they also caused high nutrient extraction. High technological level resulted in higher levels of productivity (194 GJ ha-1), balance of C (602 kg ha-1), N (-97.5 kg ha-1) and P (13.7 kg ha-1), as well as increased water use efficiency (8.95 kg ha-1 mm-1) compared to the medium technological level. The increasing demand for food and the search for resilient agricultural practices that combine productive and ecological aspects highlight the importance of diversified production based on indicators, allowing for sustainable food production systems.
       
  • INSECT-RESISTANT MAIZE HYBRIDS TOLERANT TO GLUFOSINATE DUE TO THE pat
           GENE, UNDER DIFFERENT GLUFOSINATE RATES

    • Abstract: ABSTRACT The use of glufosinate may have different effects on maize, with greater symptoms of injury for technologies with lower expression of the pat gene. As tolerance may vary with technology, it is important to investigate the selectivity of glufosinate in maize hybrids with the pat gene (resistant to insects). The objective of this study was to evaluate the selectivity of glufosinate rates applied in post-emergence, in insect-resistant transgenic maize with the pat gene. The experiment was carried out in Palotina, state of Paraná, Brazil, in 2020. A randomized block design with a factorial scheme (9x4) was used. The treatments were 9 maize hybrids and 4 glufosinate rates (0, 500, 700 and 1,000 g of active ingredient [ai] ha-1). Injury symptoms, plant height, 1,000-grain mass and yield were evaluated. The results showed that injury increases with increasing glufosinate rates. For plant height and 1,000-grain mass, a significant effect was detected only for hybrids, while there was no effect on yield, even at the highest rates. Glufosinate was selective for insect-resistant maize hybrids with the pat gene, up to the rate of 1,000 g ai ha-1, presenting initial injuries and some differences between maize hybrids. However, there was no impact on yield.
       
  • COMPARISON BETWEEN THE EFFECTIVENESS AND SENSITIVITY OF THE SUGAR SHAKE
           METHOD VERSUS THE SOAPY WATER WASHING TECHNIQUE TO DETECT PHORETIC MITES
           OF Varroa destructor

    • Abstract: ABSTRACT Colony infestation caused by Varroa destructor is a major concern in the apiculture industry because it often results in production losses and reduced colony survival. Over the years, several diagnostic methods have been developed to estimate Varroa infestation levels in a colony, being Soapy Water Washing (SWW) and Sugar Shake (SS) the most widely used methods. However, the effectiveness and sensitivity of the latter remain unclear. This represents a potential risk for beekeepers who use SS as it could lead them to underestimate the infestation level of their colonies, potentially delaying treatment application. The objective of this study was to evaluate the effectiveness and sensitivity of SS as compared to the "gold standard" SWW, for the detection of V. destructor in adult bees. Ninty-nine samples were collected and divided into 3 groups according to infestation rate (IR): low (<3%); medium (3.01-5.0%); and high (>5.01%). It was found that the SS and SWW methods showed 76.6% and 100% effectiveness of mite removal, respectively (p< 0.05). The sensitivity of SS was lower as compared to SWW. In samples with a low IR, 5 of them resulted in false negatives and 23 had a poorly estimated IR. This did not occur in samples with a medium or high IR. Our results suggest that the SS method is less efficient in detecting and removing phoretic mites in adult bee samples, which can underestimate Varroa infestation levels, especially when the number of mites is low.
       
  • NATIVE AND NATURALIZED PASTURE GRASSES OF SOUTHERN CHILE: PHYSICAL AND
           GERMINATIVE CHARACTERISTICS OF THE SEEDS AND VIGOR OF ESTABLISHMENT

    • Abstract: RESUMEN Las praderas dominadas por especies nativas y naturalizadas constituyen un porcentaje significativo de la superficie total de praderas en el sur de Chile. Sin embargo, la información sobre estos ecosistemas es escasa, particularmente en lo que respecta a las semillas de las especies que los componen. El objetivo de este estudio fue evaluar las características germinativas y de establecimiento de Bromus valdivianus Phil., Paspalum dasypleurum Kunza ex Desv., Holcus lanatus L., Agrostis capillaris L. y Arrhenaterum elatius L. spp. bulbosus (Wild), provenientes de dos zonas geográficas del sur de Chile y clasificadas en dos tamaños de semilla contrastantes. Las zonas evaluadas fueron el sector precordillerano (Cordillera de la Costa) de la comuna de La Unión y el sector precordillerano (Cordillera de los Andes) de la comuna de Lago Ranco. Se realizó un análisis de germinación para determinar el porcentaje y tasa de germinación, diámetro, longitud y peso de 1000 semillas. Posterior a ello, se determinó el vigor de germinación, cuantificando longitud foliar, peso aéreo, radical y total de cada especie para cada tratamiento. Además, se realizaron ensayos en macetas bajo condiciones controladas de temperatura, luz y humedad para determinar el vigor de establecimiento, cuantificándose los mismos parámetros evaluados para el vigor de germinación. Los datos fueron analizados bajo un diseño completamente al azar anidado. B. valdivianus fue la especie que presentó mejor desempeño en todas las variables evaluadas (P < 0,05). En cuanto a la localidad, Lago Ranco dio origen a semillas más grandes y La Unión a semillas de mejor germinación. En términos de tamaño, las semillas grandes demostraron ser más vigorosas y tener un mejor desempeño germinativo. Se concluyó que el porcentaje, la tasa de germinación, el vigor de germinación y de establecimiento varían entre tamaño de semilla y localidad de origen dentro de la misma especie.ABSTRACT Pastures dominated by native and naturalized species account for a large portion of the total grassland area in southern Chile. However, information on these ecosystems is scarce, particularly with respect to the seeds of the species that compose them. The objective of this study was to evaluate the physical and germinative characteristics of Bromus valdivianus Phil., Paspalum dasypleurum Kunza ex Desv., Holcus lanatus L., Agrostis capillaris L. y Arrhenaterum elatius L. spp. bulbosus (Wild), collected from two geographical areas of southern Chile and classified into two contrasting sizes. The areas evaluated were the foothills (Coastal Mountain Range) of the commune of La Unión and the foothills (Los Andes Mountain Range) of the commune of Lago Ranco. Seed germination percentage, germination rate, diameter, length, and 1000 seed weight were determined. Subsequently, germination vigor was determined by measuring leaf length, aerial weight, root weight and total weight of the species. In addition, a pot experiment was conducted under controlled conditions of temperature, light and humidity to determine establishment vigor, measuring the same parameters as for germination vigor. The data were analyzed under a completely randomized nested design. Bromus valdivianus Phil. was the species that showed the best performance in all the evaluated variables (P < 0.05). In terms of locality of origin, Lago Ranco recorded larger seeds, while La Unión presented better germination. In terms of size, large seeds proved to be more vigorous and had better germination performance. It was concluded that germination percentage and rate as well as vigor of germination and establishment vary between seed size and locality of origin within the same species.
       
  • TOTAL CARBOHYDRATE MOBILIZATION AND CRUDE PROTEIN CONTENT OF Adesmia
           bicolor (Poir.) DC. CROP UNDER PHOSPHORUS FERTILIZATION

    • Abstract: RESUMEN En la región árida-semiárida central de Argentina la disponibilidad de biomasa de los pastizales naturales en el periodo de bajas temperaturas es escasa, por lo que es importante lograr una mayor producción de especies forrajeras de crecimiento invernal. Entre estas especies se encuentra Adesmia bicolor (Poir.) DC, leguminosa perenne, de ciclo indefinido, herbácea, con crecimiento clonal, lo que favorece su persistencia bajo pastoreo intensivo, y una elevada capacidad para fijar nitrógeno (N). Existe escasa información respecto al comportamiento de este cultivo bajo fertilización. Por tanto, el objetivo de este estudio fue evaluar la producción de biomasa, contenido de proteína bruta y movilización de carbohidratos totales de A. bicolor bajo fertilización con fósforo (P). El ensayo se llevó a cabo en una parcela con A. bicolor en cultivo ya establecido. El diseño empleado fue de bloques completos al azar con tres repeticiones. Los tratamientos aplicados fueron tres dosis de fertilizante fosfatado líquido: Tratamiento I: 0 kg ha-1 (control); Tratamiento II: 50 kg ha-1 y Tratamiento III: 100 kg ha-1. Se realizaron seis muestreos cada 60 días en los que se determinó: biomasa aérea y subterránea, porcentaje de proteína bruta y concentración de carbohidratos totales. Los resultados mostraron que la mayor producción de biomasa se obtuvo con la dosis de 50 kg ha-1, el contenido de proteína bruta en biomasa aérea y subterránea fue similar en todos los tratamientos y el patrón de movilización de carbohidratos no se vio favorecido significativamente por la aplicación de P.ABSTRACT In the arid-semi-arid central region of Argentina, biomass availability from natural grasslands in the period of low temperatures is scarce, and therefore achieving a higher production of winter-growing forage species is important. One of these species is Adesmia bicolor (Poir.) DC., a perennial herbaceous legume with an indefinite cycle and clonal growth, which favors its persistence under intensive grazing and high capacity to fix nitrogen (N). There is little information about the behavior of this crop under fertilization. Therefore, the objective of this work was to evaluate biomass production, crude protein content and total carbohydrate mobilization of A. bicolor under phosphorus fertilization. The experiment was carried out in a plot with an already established A. bicolor crop. A randomized complete block design with three replicates was used. The treatments consisted of three doses of liquid phosphate fertilizer: Treatment I: 0 kg ha-1 (control); Treatment II: 50 kg ha-1, and Treatment III: 100 kg ha-1. Six samples were collected every 60 days, and aboveground/ belowground biomass, crude protein and total carbohydrate content were determined. The results showed that Treatment II (50 kg ha-1) recorded the highest level of biomass production of all the treatments, whereas the different fertilizer doses did not affect crude protein content of aboveground/ belowground biomass or carbohydrate mobilization patterns.
       
  • SOIL CHARACTERISTICS AND SALICYLIC ACID SUPPLEMENTATION IN CASTOR BEAN
           (Ricinus communis L.) OIL PRODUCTION

    • Abstract: ABSTRACT Castor bean (Ricinus communis L.) is an oleaginous plant of economic importance due to its different industrial applications. Edaphic characteristics are used to determine the viability of places considered as suitable to obtain castor oil. The objectives of this study were to determine the edaphic characteristics and oil content of R. communis, and to evaluate elicitation with salicylic acid (SA) in El Marqués, Querétaro, Mexico. Sampling was carried out in a direct way, selecting sites where castor bean plants were found. Samples of 1.5 kg of soil were taken and 3 clusters of castor bean in a mature state were collected from 21 accessions. The physicochemical characteristics of the soil and oil content of seeds were determined. Finally, 300 plants of the Guanajuatoil variety were planted and elicitated with different SA concentrations under greenhouse conditions in order to determine oil content. The physical analysis of the soil samples indicated dark-colored soils, Mollisol and Vertisol types, with different textures: clay, clay loam, sandy clay loam and sandy loam. Soil chemical analyses showed the following soil characteristics: pH 7.22; electrical conductivity 0.52 dS m-1; organic matter 7.17%; cation exchange capacity 26.77; calcium 38.62, magnesium 6.81, sodium 13.41and potassium 6.97 cmol kg-1; and nitrogen and phosphorus contents of 16.32 and 54 mg kg-1, respectively. Castor oil content was higher in clay soils (41.46%). The plants elicited with SA presented oil contents ranging from 28.99% to 52.9%, obtained with 100 and 900 ^M. In conclusion, elicitation with SA is an adequate method to increase oil content in castor bean seeds. The locality of El Marqués has good potential for the production of castor oil.
       
  • DID WE UNDERESTIMATE SILT AND CLAY CONTENT IN THE TEXTURAL ANALYSIS'

    • Abstract: ABSTRACT Particle size distribution (PSD) is a soil physical property influenced by organo-mineral complexes (or-mic) in silt and clay fractions. In Andosols, these fractions are underestimated due to the presence of or-mic in soil micro-aggregates. This study estimated quantitatively the organo- mineral fraction by comparing two methodologies of granulometric analysis (sequential dispersion and sieve-sedimentation) in Andosols and Fluvisols from southern Chile. Or-mic were calculated through specific dissolution extractions (Al, Si, Fe). In addition, pHNaF, and soil organic carbon (SOC) were determined. Correlations between Alo (0.74), Alp (0.71), pH in NaF (0.41), and the or-mic were found. Or-mic were higher in Andosols, varying between 1.5 and 5.2%, which led to an underestimation of silt and clay fractions of the soil in PSD analysis and, thus, an overestimation of soil texture due to the continuous formation of micro-aggregates. Therefore, to properly determine soil PSD, it is essential to estimate or-mic, particularly in highly reactive soils, which are readily capable of binding organic compounds in their mineral fraction.
       
  • IMPACT OF THREE TILLAGE SYSTEMS ON THE FERTILITY OF AN ENTISOL SOIL IN
           ARID ZONES

    • Abstract: RESUMEN La implementación de inadecuados sistemas de labranza en terrenos de zonas áridas provoca la degradación de la fertilidad de suelo. El objetivo de este estudio fue determinar el impacto de tres sistemas de labranza sobre la fertilidad de un suelo Entisol en una zona árida. Se evaluó la estructura, macrofauna, materia orgánica, nitrógeno, fósforo, potasio, pH, salinidad y capacidad de intercambio catiónico (CIC) del suelo. La investigación se desarrolló en la Irrigación Majes, Arequipa, Perú. Los tratamientos fueron: T1) labranza horizontal (arado de discos, grada, sembradora); T2) labranza vertical (arado de cinceles, grada, sembradora); y T3) no labranza (sembradora). El diseño experimental empleado fue bloques completos al azar con tres repeticiones, y evaluaciones a 3, 10 y 17 meses. Cada tratamiento recibió la incorporación de maíz (Zea mays) y frejol (Phaseolus vulgaris) como abono verde a 30 días de la siembra en cada caso. Los tres sistemas de labranza favorecieron la formación de estructuras de tipo bloque angular de tamaño muy fino y fino, con grado de agregación débil a moderado. La composición y abundancia de macrofauna se incrementó conforme aumenta el tiempo de laboreo. La materia orgánica no presentó diferencias estadísticas significativas entre los sistemas de labranza. No se detectaron diferencias estadísticas significativas en los niveles de N, P y pH. La labranza horizontal favoreció la presencia de potasio y la CIC, y limitó la presencia de sales, con diferencia estadística significativa respecto a labranza vertical y no labranza.ABSTRACT The implementation of inadequate tillage systems in arid zone lands causes the degradation of soil fertility. The objective of this study was to determine the impact of three tillage systems on the fertility of an Entisol soil in an arid zone. Soil structure, macrofauna, organic matter, nitrogen, phosphorus, potassium, pH, salinity and cation exchange capacity (CEC) were evaluated. The research was carried out at Majes Irrigation, Arequipa, Peru. The treatments were: T1) horizontal tillage (disc plow, harrow, seeder); T2) vertical tillage (chisel plow, harrow, seeder); and T3) no tillage (seeder). The experimental design used was randomized complete blocks with three replicates, and evaluations after 3, 10 and 17 months. Corn (Zea mays) and beans (Phaseolus vulgaris) were applied as green manure at 30 days after sowing to each treatment. The three tillage systems favored the formation of angular block-type structures of very fine and fine size, with a weak to moderate degree of aggregation. The composition and abundance of macrofauna increased as tillage time increased. Organic matter did not present statistically significant differences between tillage systems. No statistically significant differences were found in terms of N, P or pH. Horizontal tillage favored the presence of potassium and CEC, and limited the presence of salts, with a statistically significant difference with respect to vertical tillage and no tillage.
       
  • CHARACTERIZATION AND VALORIZATION OF CHILEAN FRUIT EXPORT REFUSALS FOR
           TECHNICAL REASONS

    • Abstract: RESUMEN Dentro de las medidas no arancelarias (MNA) de tipo técnico tenemos las medidas sanitarias y fitosanitarias (MSF), las cuales consideran aspectos específicos en calidad e inocuidad. El análisis del impacto de las MSF se ha centrado en la estimación mediante modelos gravitacionales de sus efectos sobre los flujos de importación y exportación. Una forma menos explorada de abordar los efectos de las MSF es el estudio de los rechazos de exportaciones por su incumplimiento, sobre todo en lo que se refiere a la valorización económica de dichos rechazos. Por tanto, el objetivo del presente estudio fue caracterizar y valorizar, desde el punto de vista del flujo comercial, los rechazos de exportaciones por motivos técnicos, considerando para ello el caso de las exportaciones frutícolas chilenas al mercado de Estados Unidos. Se aplicó una metodología cuantitativa de tipo descriptivo, iniciando con la compilación de una base de datos a partir de información secundaria (registros de rechazos de la Administración de Alimentos y Medicamentos de Estados Unidos y de exportación de la Oficina de Estudios y Políticas Agrarias de Chile) y primaria (consultas a exportadores), y posteriormente mediante un análisis descriptivo y la aplicación de una ecuación de valorización económica. Los resultados muestran que el valor de los rechazos - mayoritariamente por un uso de pesticidas superior a la norma - tiene una participación muy baja en relación con el total del valor de la fruta exportada a Estados Unidos por parte de Chile durante el periodo analizado. Ello podría deberse al desarrollo del sistema de inocuidad chileno, a un "efecto reputación" y/o a la no competencia directa local.ABSTRACT Sanitary and phytosanitary measures (SPS) are within technical non-tariff measures (NTM), as they include aspects regarding quality and safety of food products. The analysis of the impact of SPS has focused on the estimation by gravity equations of their effects on import and export flows. A less explored way of addressing SPS is the study of export refusals due to non-compliance, especially regarding the economic assessment of such refusals. Therefore, the objective of this study was to characterize and value export refusals for technical reasons from the point of view of trade flows, considering the case of Chilean fruit exports to the United States market. A descriptive quantitative methodology was applied, starting with the compilation of a database from secondary sources (refusals records from the US Food and Drug Administration and export figures from the Office of Agricultural Studies and Policies of Chile) and primary sources (exporters' survey), followed by a descriptive analysis and application of a novel economic assessment equation. The results show that the value of refusals - most of them due to pesticide residue exceeding maximum limits - has a very low share in relation to the fruit exported to the USA. This could be due to the strength of the Chilean safety system, to a "reputation effect" and/or to non-direct competition with local production.
       
  • CARCASS INDICES AND MEAT QUALITY OF BROILER CHICKENS FED DIETS CONTAINING
           FORTIFIED FERMENTED CASSAVA STUMP

    • Abstract: ABSTRACT A 56-day study was conducted to evaluate carcass and meat quality of broiler chickens fed diets containing fortified fermented cassava stump (FFCS) as a replacement for maize. Cassava stumps and leaves were fermented in the solid state at room temperature, using Aspergillus niger ATCC 16404 for 192 and 96 hours, respectively, and then mixed at a ratio of 19:1 to obtain the FFCS. The birds were allotted into four treatments with three replicates (n= 30). The treatments consisted of different inclusion levels of FFCS: Diet 1 containing 0% FFCS (control treatment); Diet 2 containing 20% FFCS; Diet 3 containing 40% FFCS; and Diet 4 containing 60% FFCS. Dressing and eviscerated percentages were higher (p < 0.05) in birds fed the diets with up to 40% FFCS. The carcass yield was not significantly influenced (p > 0.05) by the inclusion of FFCS, but values obtained were higher with up to 40%. Meat quality was significantly (p < 0.05) influenced by the FFCS. In addition, the degree of meat peroxidation decreased with increased FFCS levels. Diets with up to 40% FFCS inclusion resulted in improved carcass traits, oxidative stability, and meat quality. Therefore, the addition of fortified cassava stump in broiler chickens' diets could produce meat of better quality, with low peroxidation, high oxidative stability, and longer shelf-life.
       
  • EFFECT OF DIETS WITH LOWER THAN RECOMMENDED PROTEIN AND FIBER CONTENT ON
           THE GROWTH OF MUSCOVY DUCKS (Cairina moschata Linnaeus, 1758)

    • Abstract: RESUMEN Dietas diluidas en nutrientes, con un menor contenido de proteína y mayor contenido en fibra, pueden ser elaboradas con la finalidad de disminuir el costo del alimento. El presente estudio evaluó el efecto de dietas con contenido de proteína y fibra por debajo del estándar recomendado sobre el crecimiento de patos machos Muscovy (Cairina moschata Linnaeus, 1758) desde los 28 hasta los 77 días de edad. El análisis químico proximal determinó el contenido de proteína y fibra en 8,4 y 3,0% para la dieta 1 y 14,8 y 6,3% para la dieta 2, respectivamente. El consumo de la dieta 1 disminuyó la ganancia de peso, mostró tendencias de menor rendimiento de la canal y peso del hígado, y aumentó el tamaño del intestino comparado con el consumo de la dieta 2. La deposición de grasa abdominal no fue influenciada por las dietas. La excesiva disminución de proteína en la dieta conllevaría a la aparición de nutrientes que limitan la síntesis de proteínas corporales, lo que se reflejarían en la menor ganancia de peso y rendimiento de la canal. La tendencia de menor peso hepático y menor longitud intestinal, en patos que consumieron dietas altas en fibra, sugieren menor depósito de grasa en el hígado y disminución del área de absorción intestinal por efecto de la fibra, respectivamente.ABSTRACT Nutrient-diluted diets, with lower protein and higher fiber contents, can reduce the cost of food. The present study evaluated the effect of diets with protein and fiber contents below the recommended standard on the growth of male Muscovy ducks (Cairina moschata Linnaeus, 1758) from 28 to 77 days of age. The proximal chemical analysis determined protein and fiber contents of 8.4 and 3.0% for diet 1 and 14.8 and 6.3% for diet 2, respectively. Diet 1 resulted in decreased weight gain, trends for lower carcass yield and liver weight, and increased gut size compared to diet 2. Abdominal fat deposition was not influenced by the diets. The excessive decrease in protein would lead to the appearance of nutrients that limit the synthesis of body proteins, resulting in lower weight gain and yield of the carcass. The trend of lower liver weight and shorter intestinal length in ducks that consumed high-fiber diets suggest less fat deposition in the liver and decreased intestinal absorption area due to the effect of fiber, respectively.
       
 
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