Evaluación agronómica, nutricional y ambiental de 130 accesiones de Megathyrsus maximus para selección en el Valle del Patía - Cauca Colombia

Se evaluaron aspectos agronómicos, nutricionales y ambientales de una colección de 130 accesiones de Megathyrsus maximus en épocas de máxima y mínima precipitación, en el Valle del Patía, zona representativa de trópico seco colombiano, que presenta lluvias concentradas en dos épocas del año (abril-mayo y noviembre-diciembre) con periodos prolongados de sequía. A través de un diseño de bloques completos al azar, evaluaciones por un periodo de dos años y con metodologías de: la RIEPT, NIRS y tasas de nitrificación se evidenció que la época influye en el comportamiento agronómico, morfológico y nutricional de M. maximus favoreciendo el desempeño en época de alta precipitación, en contraposición a la floración y porcentaje de materia seca; se observó que el contenido de FDN, FDA y DIVMS, difirieron levemente comparados con la época de mínima precipitación. No obstante, se destacan accesiones con mayor tolerancia a condiciones de época seca. Paralelamente, se identificó 12 mateiales con producciones de materia seca mayor a 6t/ha/pastoreo y 4t/ha/pastoreo para época de máxima y mínima precipitación respectivamente, con adecuado vigor, altura, buen consumo por los animales y sin afectación económica de plagas y enfermedades pero con floración variable entre los genotipos; además tres de estas accesiones se destacaron por la baja tasa de nitrificación lo que sugiere potencial inhibición biológica de la nitrificación (IBN), como propiedad innovadora de la especie en la zona, lo que las define como materiales con potencial para un programa de mejoramiento genético y para uso en ganaderías ecoeficientes.//Abstract: The agronomic, nutritional and environmental aspects of a collection of 130 accessions of Megathyrsus maximus were evaluated in the maximum and minimum wet seasons, in Patía Valley, an area representative of the dry Colombian tropic, which presents concentrated rains at two seasons of the year (April-May and November-December) with prolonged periods of drought. Through a randomized complete block design, evaluations for a period of two years, and with methodologies of: The International Evaluation Network for Tropical Pasture, Near-Infrared Spectroscopy and nitrification rates, it was evidenced that the season influences the agronomic, morphological and nutritional behavior of M. maximus favoring the performance in the high precipitation season, as opposed to the flowering and percentage of dry matter; it was observed that the content of neutral detergent fiber (NDF), acid detergent fiber (ADF) and in vitro digestibility of dry matter (IVDMD), differed slightly compared with the time of minimum precipitation. However, accessions with greater tolerance to dry season conditions stand out. In parallel, 12 accessions were identified with productions of dry matter greater than 6t / ha / grazing and 4t / ha / grazing for peak and minimum rainfall respectively, with adequate vigor, height, good consumption by the animals and without economic affectation of pests and diseases but with variable flowering among the genotypes; In addition, three of these accessions were highlighted by the capacity of biological inhibition of nitrification (IBN), as an innovative property of the species in the area, which defines them as materials with potential for a breeding program and for use in LivestockPlus.Doctorad

Digestibilidad de la harina de guandúl (cajanus cajan) en alimentación de pollos de engorde

With the objective of evaluate the apparent digest of foodstuff and protein of diets with the inclusión of guandul grain fluor as an alternative source for broiler chicken growth, there were used 96 male animals of the Cobb 500 line distributed in 16 metabolic cages,using an experimental design completely at random (DCA) with four treatments, four repetitions and six animals per experimental unit, the treatments were 4 diets iso-protein and iso-energetic with levels of inclusión of 0,10,20 and 30% of guandul fluor. In the results there were observed different meaningful statistics (p≤0,05) in the starter phase, the treatments T0 and T1 were statistically different from treatments with bigger guandul inclusion T2 y T3. In the ended phase the treatments T0 and T1 were equal statistically, being different from treatments T2 and T3 in which there were not meaningful differences of statistics. In the ended phase of the chicken diet it may even include a 10% of guandul flour as a protein source without affecting negatively in the apparent digest of the food and protein.Con el objetivo de evaluar la digestibilidad aparente del alimento y la proteína de dietas con inclusión de harina de grano de guandúl como fuente alternativa de alimentación para pollos de engorde, se utilizaron 96 animales machos recriados de la línea Cobb 500 distribuidos en 16 jaulas metabólicas, empleando un diseño experimental completamente al azar (DCA) con cuatro tratamientos, cuatro repeticiones y seis animales por unidad experimental, donde los tratamientos fueron  4 dietas iso-protéicas e iso-energéticas con niveles de inclusión de 0, 10, 20 y 30% de harina de guandúl. En los resultados se observó diferencias estadísticas significativas (p≤0,05) en la etapa inicial, los tratamientos T0 y T1 fueron estadísticamente diferentes a los tratamientos con mayor inclusión de guandúl T2 y T3. En la etapa final los tratamientos T0 y T1 fueron iguales estadísticamente diferenciándose de los tratamientos T2 y T3 entre los cuales no se presentó diferencias estadísticas significativas. En la etapa final de la alimentación de pollos se puede incluir hasta el 10% de harina de guandúl como fuente protéica sin presentar diferencias estadísticas significativas de las digestibilidades aparentes del alimento y de la proteína.

Digestibilidad in vitro Prececal y Cecal de plantas forrajeras tropicales para la nutrición en cerdos

Con el objetivo de evaluar nutricionalmente el follaje de leguminosas tropicales Canavalia (C. brasiliensis), Desmodium (D. velutinum), Caupi (V. unguiculata), Stylosanthes (S. guianensis), Cratylia (C argentea), Lablab (L purpureus), Centrosema (C. molle) y Centrocema brasilianum mediante pruebas de composición química, digestibilidad in vitro prececal de materia seca,(DIMS) energía (DIVE) y proteína (DIVP) y fermentación in vitro cecal. Se encontró C. molle y V. unguiculata tuvieron valores superiores en DIVMS y DIVE sin presentar diferencias estadística significativas (P0,001) los valores menores fueron para S. guianensis y C. brasilianum; las leguminosas C. molle, C. argentea y D. velutinum presentaron DIVP de 62,2; 61,4 y 59,7% respectivamente.//Abstrac: In order to evaluate nutritionally foliage of tropical legumes Canavalia (C. brasiliensis), Desmodium (D. velutinum), Cowpea (V. unguiculata), Stylosanthes (S. guianensis), Cratylia (C argentea), Lablab (L purpureus) , Centrosema (C. molle) and Centrocema brasilianum by chemical tests, in vitro digestibility of dry matter prececal (DIMS) energy (DIVE) and protein (DIVP) and cecal fermentation in vitro. It was found and V. unguiculata y C. molle had higher values in IVDMD and DIVE without no differences statistically significant (P 0.001) minor values were for S. guianensis and C. brasilianum, and legumes C. molle, C. argentea and D. velutinum presented DIVP 62.2, 61.4 and 59.7% respectively.Maestrí

Digestibilidad de la harina de guandúl (cajanus cajan) en alimentación de pollos de engorde

Con el objetivo de evaluar la digestibilidad aparente del alimento y la proteína de dietas con inclusión de harina de grano de guandúl como fuente alternativa de alimentación para pollos de engorde, se utilizaron 96 animales machos recriados de la línea Cobb 500 distribuidos en 16 jaulas metabólicas, empleando un diseño experimental completamente al azar (DCA) con cuatro tratamientos, cuatro repeticiones y seis animales por unidad experimental, donde los tratamientos fueron  4 dietas iso-protéicas e iso-energéticas con niveles de inclusión de 0, 10, 20 y 30% de harina de guandúl. En los resultados se observó diferencias estadísticas significativas (p≤0,05) en la etapa inicial, los tratamientos T0 y T1 fueron estadísticamente diferentes a los tratamientos con mayor inclusión de guandúl T2 y T3. En la etapa final los tratamientos T0 y T1 fueron iguales estadísticamente diferenciándose de los tratamientos T2 y T3 entre los cuales no se presentó diferencias estadísticas significativas. En la etapa final de la alimentación de pollos se puede incluir hasta el 10% de harina de guandúl como fuente protéica sin presentar diferencias estadísticas significativas de las digestibilidades aparentes del alimento y de la proteína.

Risk of COVID-19 after natural infection or vaccinationResearch in context

Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health

Risk of COVID-19 after natural infection or vaccinationResearch in context

Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health