Dietas con follaje de yuca y su efecto sobre las características al sacrificio y rendimiento en canal y en cortes de pollos de engorde / Diets with cassava foliage meal and its effect on the slaughter traits and carcass and retail cuts yield of broilers

Para evaluar el efecto de la incorporación de la harina de follaje de yuca (HFY) en niveles crecientes (0; 2,5; 5 y 7,5%) en raciones alimenticias para pollos de engorde sobre las características al sacrificio y el rendimiento en canal y en cortes, se usaron 32 pollos de engorde, hembras de la raza Cobb de 42 días de edad. El análisis de la varianza detectó efectos significativos (P<0,05) del nivel de HFY sobre rendimiento de la cabeza, obteniéndose los mayores valores (3,26 y 2,72%, respectivamente) con 5 y 7,5% de HFY. La inclusión de HFY produjo un aumento del 6% (P<0,05) en el rendimiento del muslo, con o sin cadera, pero no afectó significativamente el rendimiento de la canal fría ni ningún otro corte. La utilización de HFY en la alimentación de pollos de engorde a niveles de 7,5%, no ocasionó detrimento en algunos de los parámetros productivos, ni produjo efectos negativos en las características al sacrificio ni en el rendimiento en los diferentes cortes.

To study the effect of incorporation of cassava foliage meal (CFM) at increasing levels (0; 2.5; 5 and 7.5%) in food rations for broilers on carcass traits and retail cuts yield were used 32 broilers, females, Cobb breed, with 42-d old). The analysis of variance detected significant effects (P <0.05) of level of inclusion of CFM on the head percentage. The highest values in head percentage (3.26 and 2.72%, respectively) were found with 5 and 7.5% of CFM. The inclusion of CFM only showed an increase of 6% (P <0.05) for the percentage of leg (drumstick-thigh combination) and leg quarter (with the back portion included). However, the chilled carcass yield was not affected significantly by the treatments. The use of CFM in feeding stuffs for broilers up to 7.5%, did not cause a detriment of the productive performance and did not has a negative effect on slaughter characteristics or retail cuts yields.

Efecto de la ingestión de cultivo Saccharomyces cerevisiae y selenio en pollos de engorde expuestos a bajos niveles de aflatoxina B1 en la dieta / Effect of Saccharomyces cerevisiae Culture and Selenium Intake in Broiler Chickens Exposed to Low Levels of Aflatoxin B1 in the Ration

El presente estudio determinó el efecto de 0,1% de cultivo de levadura Saccharomyces cerevisiae (CSc) y 2 mg/kg de selenio (Se) sobre los índices productivos y concentración de proteínas totales en pollos de engorde que recibieron dietas con 0,07 mg/kg de aflatoxina B1 (AFB1). Un total de 480 pollos de engorde, de un día de nacidos, fueron asignados al azar para recibir 8 tipos de dietas durante 42 días. Se registró el peso de las aves (P), consumo de alimento (C), conversión de alimento (CV), ganancia de peso corporal (GPC), mortalidad (M) y a los 42 días se tomó suero sanguíneo de cada grupo para determinar la concentración de proteínas totales (PT). Las dietas correspondieron a los siguientes tratamientos (T) T1: grupo control que consiste en alimento comercial (AC) sin niveles detectables de aflatoxina; T2: AC + AFB1; T3: AC + CSc; T4: AC + AFB1 + CSc; T5: AC + Se; T6: AC + AFB1 + Se; T7: AC + CSc + Se; T8: AC + AFB1 + CSc + Se. La inclusión de CSc y/o Se en dietas con o sin AFB1 no alteró (P>0,05) el P, GPC, CV PT. El C incrementó (P£0,01) con la inclusión de CSc y/o Se en el alimento con AFB1 (T4, T6, T8), con respecto a los pollos que recibieron CSc y/o Se sin AFB1 (T3, T5, T7). La M en aves que recibieron AFB1 (T2, T4, T6, T7), incrementó (P<0,15), con respecto a las que recibieron dietas sin AFB1 (T1, T3, T5, T7). Estos resultados sugieren que la ingestión durante 42 días de 0,07 mg/kg de AFB1 en la dieta de pollos de engorde, puede tener efectos en algunos parámetros productivos, pudiendo aumentarse el consumo de alimento sin cambios en el P, GPC y CV por la inclusión individual o combinada de CSc y Se en las dietas contaminadas.

The present study determine the effect of 0.1% of yeast Saccharomyces cerevisiae (CSc) and 2 mg/kg de selenium (Se) over productive ranges and total protein concentrations on broiler chickens feed with a diet contaminated with 0.07 mg/kg of aflatoxin B1 (AFB1). 480 newborn broiler were randomly organized to receive 8 different diet during a 42 days period. Weight (P), Daily consume (C), Food convertion (CV) corporal weight gain (GPC), mortality (M) of broiler and at 42 days it was took blood serum of each group to determine total protein (PT) concentration. Diets corresponded the following treatments (T). T1: control group constitute by a commercial diet (AC) without any detectable level of aflatoxins; T2: AC + AFB1; T3: AC + CSc; T4: AC + AFB1 + CSc; T5: AC + Se; T6: AC + AFB1 + Se; T7: AC + CSc + Se; T8: AC + AFB1 + CSc + Se. The inclusion of CSc and/or Se diets with or without AFB1 did not affect (P>0.05) P, GPC, CV and PT. The increase of C (P£0.01) with inclusion of CSc and/or Se at feeding with AFB1 (T4, T6, T8), compared to boilers that received CSc and/or Se without AFB1 (T3, T5, T7). M on broilers that received AFB1 (T2, T4, T6, T8) incremented (P<0.15) compared to broilers that received a feeding without AFB1 (T1, T3, T5, T7). These results suggest that the ingestion during 42 days period with 0.07 mg/kg of AFB1 on diet of broiler, could have some effects on production parameters increasing consume of food without changes for P, GPC and CV by individual or combined inclusion of CSc and Se on contaminated diets.

Protein extraction and enzymatic hydrolysis of ammonia-treated cassava leaves (Manihot esculenta Crantz).

In the present work, cassava leaves were treated with 0.5 kg ammonia/kg dry matter at 78 degrees C and 30% moisture content in a 2-kg reactor. Protein extraction was carried out with a calcium hydroxide solution (pH 10) for 30 min at several temperatures (30 degrees C, 45 degrees C, 60 degrees C, 75 degrees C, and 90 degrees C) and solid/liquid ratios (1:10 and 1:15) in a thermostatized bath. Soluble protein content of the extracts was determined by Lowry's method. Dry substrate concentrations of 5%, 7.5%, and 10% and enzyme doses of 2 and 5 IU/g dry matter were used for the enzymatic hydrolysis in an orbital incubator at 50 degrees C and 100 rpm. Both cellulase and xylanase were used. Reducing sugars produced were determined with the dinitrosalicylic acid method. The highest protein extraction yield for the ammonia-treated leaves was 29.10%, which was 50% higher than with the untreated leaves (20%), and was obtained at 90 degrees C with a 1:10 solid/liquid ratio. The concentrate had a protein content of 36.35% and the amino acid profile was suitable for swine and poultry. The highest sugar yield was 54.72% with respect to theoretical and was obtained with 5% solids and an enzyme dose of 5 IU/g dry matter. This yield was 3.4 times higher than the yield of the untreated leaves (16.13%). These results indicate that cassava leaves have a great potential for animal feeding and ethanol production. Both protein extraction and sugar yields may be enhanced by optimizing the ammonia treatment.

Leaf protein from ammonia-treated dwarf elephant grass (Pennisetum purpureum Schum cv. Mott).

Proteins can be an excellent byproduct of the biorefining of lignocellulosic materials. In this work, extraction conditions for the white leaf proteins (cytoplasmic) of ammonia-treated dwarf elephant grass were established to obtain a protein juice suitable for the production of leaf protein concentrates. A calcium hydroxide solution was used as extracting agent, at several solid-liquid ratios, pHs, temperatures, and times. Extractions were carried out in Erlenmeyer flasks containing 5 g (dry basis) of forage with constant agitation (100 rpm). The soluble protein content was determined by the Lowry method. Optimal extraction conditions for the ammonia-treated forage were 12.60 pH, 1:10 solid-liquid ratio, 90 degrees C, and 30 min extraction time, resulting in 52.65% extraction yield. The ammonia treatment significantly increased (p<0.05) the release of proteins from the fibrous matrix, facilitating their extraction.

Contenido de diacetilo en queso venezolano tipo palmita / Diacetyl content in venezuelan palmita type cheese

Veinte muestras de queso venezolano tipo Palmita, proveniente de dos expendios comerciales en la ciudad de Maracaibo, fueron analizadas en su contenido de diacetilo durante un lapso experimental de cinco semanas. Las muestras de queso fueron sometidas a destilación para recuperar el diacetilo formado. A 10 ml del destilado de cada queso, se le adicionó 0,5 ml de o-fenilendiamina y 2 ml de HCI para obtener valores de absorbancia del diacetilo a 340 nm, en un espectrofotómetro UV perkin-Elmer, lambda 3-ß. La concentración de diacetilo en cada muestra de queso se obtuvo a través de una curva estándar. Los resultados revelaron diferencias significativas (P<0,05) entre los quesos analizados. Las concentraciones de diacetilo variaron entre niveles de 0,92 y 6,92 ppm, los cuales están dentro del rango encontrado en los quesos Emmental, Cheddar y Parmesano

Xylanase production by Trichoderma reesei rut C-30 on rice straw.

Xylanase production of Trichoderma reesei Rut C-30 was examined at different initial pH values (4.8, 5.9, and 7.0) on rice straw in shake flasks, and in a fermentor, for the best pH condition. Enzyme performance was tested on ammonia-treated dwarf elephant grass. The maximum xylanase activities, 92 and 122 IU/mL, were obtained at pH 4.8 in the shake flasks and fermentor, respectively, in which good growth of the fungus was observed during the first 24 h and consumption of proteins dissolved from the rice straw caused the pH to rise later to values between 6.4 and 6.7 (optimal for xylanase production). The xylanases from T. reesei were as effective as Multifect XL, a commercial enzyme preparation, in hydrolyzing ammonia-treated elephant grass.

Enzymatic hydrolysis of ammonia-treated rice straw.

Rice straw pretreated with liquid anhydrous ammonia was hydrolyzed with cellulase, cellobiase, and hemicellulase. Ammonia-processing conditions were 1.5 g of NH3/g of dry matter, 85 degrees C, and several sample moisture contents. There were four ammonia addition time (min)-processing time (min) combinations. Sugars produced were analyzed as reducing sugars (dinitrosalicylic acid method) and by high-performance liquid chromatography. Monomeric sugars increased from 11% in the nontreated rice straw to 61% of theoretical in treated rice straw (79.2% conversion as reducing sugars). Production of monosaccharides was greater at higher moisture content and was processing time dependent. Glucose was the monosaccharide produced in greater amounts, 56.0%, followed by xylose, arabinose, and fructose, with 35.8, 6.6, and 1.4%, respectively.