ABSTRACT
Con el propósito de evaluar el efecto de un secuestrante comercial de micotoxinas (SM) con base en glucomananos, sobre la producción de gas y degradación ruminal in vitro, se incubó harina de granos de maíz (Zea mayz L.) en licor ruminal con concentraciones de aflatoxina B1 (AFB1) de 4, 8 y 12 ppb, respectivamente, y proporciones de AFB1: SM de 1:75000 (SM-75), 1:150000 (SM-150) y 1:225000 (SM-225). Adicionalmente, se consideró un tratamiento sin inclusión del secuestrante de micotoxinas (SM-0). La producción de gas se registró a las 3, 6, 9, 12, 16 y 24 h, y la actividad del SM a las 3 h de incubación. La información fue analizada utilizando un diseño completamente aleatorizado con arreglo factorial 3x4. La concentración de AFB1 afectó negativamente (P<0,05) la producción de gas, con el mayor impacto a las 9 h, cuando 12 ppb [5,15 mL/g de materia seca (MS)] generaron una reducción en la producción de gas, en comparación con 4 y 8 ppb (6,57 y 6,01 mL/g MS), respectivamente. Independientemente del nivel utilizado y luego de 24 h de incubación, el uso de SM incrementó (P<0,05) la producción de gas respecto al SM-0 en 25,5% (68,5 vs. 56,6 mL/g MS, respectivamente). En todos los tratamientos, SM-75 mostró la mayor producción de gas, sin mejoras debido a aumentos adicionales en la relación SM:AFB1. La concentración de AFB1 afectó (P<0,05) negativamente la degradación de la MS de la harina de maíz, con una reducción del 39,8%, luego de 12 h de incubación. La capacidad secuestrante fue del 86,0 ± 3,34%, sin diferencias (P>0,05) debida al nivel de AFB1 o a la relación AFB1:SM. Estos resultados demuestran que el aditivo biotecnológico evaluado, reduce el impacto negativo de la AFB1 sobre la producción ruminal in vitro de gas y la degradación aparente de la MS.
To evaluate the effect of a commercial mycotoxin binder (MB) based on glucomannans, on the in vitro gas production and ruminal degradation, maize (Zea mayz L.) grain meal was incubated in ruminal liquor with aflatoxin B1 (AFB1) concentrations of 4, 8 y 12, respectively, and proportions of AFB1: MB of 1:75000 (MB-75), 1:150000 (MB-150), and 1:225000 (MB-225). Additionally, a treatment without MB was considered (MB-0). Gas production was measured at 3, 6, 9, 12, 16, and 24 h, and MB activity after 3 h of incubation. Data was analyzed using a completely randomized design with a 3x4 factorial arrangement. The results show that gas production was negatively affected by AFB1 concentration (P<0.05), with the higher impact at 9 h, when 12 ppb [5.15 mL/g of dry matter (DM)] generated a reduction, when compared to 4 and 8 ppb (6.57 and 6.01 mL/g of DM, respectively). Regardless of the level used and after 24 h of incubation, the use of MB increased (P<0.05) gas production in 25.5%, compared to SM-0 (68.5 vs. 56.6 mL/g of DM, respectively). In all treatments, MB-75 showed the highest gas production without improvements, due to further increases in the ratio MB: AFB1. The AFB1 concentration negatively affected (P <0.05) degradation of DM of maize meal, with a reduction of 39.8%, after 12 h of incubation. The binding capacity was 86.0 ± 3.34%, without differences (P<0.05) due to AFB1 concentration or AFB1: MB relation. These results demonstrate that the assessed biotechnological additive reduces the negative impact of AFB1 on the in vitro ruminal gas production and apparent DM degradation.
ABSTRACT
Con el fin de detectar la presencia de hongos y aflatoxinas, en harina de maíz precocida distribuida en el estado Aragua, Venezuela, se muestrearon cuatro presentaciones comerciales durante cinco semanas. La cuantificación de hongos se realizó por el método de contaje por incorporación en placa, utilizando agar extracto de malta e incubación durante ocho días a 27± 2 ºC. La determinación de las aflatoxinas se realizó por la prueba de ELISA. El ensayo fue conducido bajo un diseño completamente aleatorio y todos los resultados fueron sometidos a la prueba estadística no paramétrica de Kruskal-Wallis y a pruebas de medias no paramétricas. Los contajes de hongos oscilaron entre 1,79 a 4,7x10UFC de hongos/g de muestra, encontrándose por debajo del nivel establecido por la Norma Covenin 1337-90 de 10(4) UFC/g de harina. Las especies fúngicas identificadas fueron: Aspergillus spp., A. flavus, A. niger, A. terreus y Penicillium spp. Los contenidos de aflatoxinas cumplieron con el nivel de tolerancia permitido para el maíz (20 ng/g).
With the purpose of detecting presence of fungi and aflatoxins in pre-cooked corn flour in Aragua State, Venezuela, we sampled four commercial presentations during five weeks. Quantification of fungi was done by the plate incorporation counting method, using malt extract agar and incubation during 8 days at 27 ± 3ºC. Aflatoxin determination was done by the ELISA test. The assay was conducted under a completely random design and all results were submitted to the Kruskal-Wallis non parametric statistical test, as well as to non parametric means tests. Fungi counts varied between 1.79 and 4.7 x 10 CFU of fungi/g of sample, indicating that they were under the level established by the COVENIN Guideline 1337-90 of 10(4) CFU/g of flour. The fungal species identified were Aspergillus spp., A. flavus, A. niger, A. terreus, and Penicillium spp. The aflatoxin content complied with the tolerance level allowed for corn (20 ng/g).
ABSTRACT
Se obtuvieron y caracterizaron las propiedades nutricionales, enzimáticas y ocratoxigénicas de aditivos enzimáticos obtenidos de residuos húmedos del procesamiento de la pasta alimenticia, fermentados mediante el monocultivo de Aspergillus niger (A1) y el cocultivo de Aspergillus niger - Saccharomyces cerevisiae (A2). Se utilizaron 150 pollitos raza Cobb-500 para evaluar el efecto de la inclusión de los aditivos A1 y A2 en 30 ppm y 3000 ppm, respectivamente, durante 21 d sobre los parámetros productivos, utilizando un diseño completamente aleatorizado. Los resultados demuestran que las actividades de las α-amilasas y glucoamilasas en el A2 fueron superiores en 42% y 69% a las del A1, respectivamente. La composición fisicoquímica y las propiedades enzimáticas de los aditivos, revelaron que éstos están compuestos principalmente por almidón y proteína, con una actividad amilolítica similar 16020 y 15540 (FAU/g), respectivamente. Sin embargo, el A2 presentó actividad de glucoamilasa (U/g) y de fitasas (U/g) superior en 58%, respecto al A1. Los niveles de ocratoxina A de 2.10-4 y 2.10-2 ppb para A1 y A2, respectivamente, fueron inferiores a la dosis letales medias (DL50) para pollos y a los límites establecidos por la FAO/OMS. Adicionalmente, la viabilidad de Aspergillus niger en A1 y A2 fue de 3.10³ UFC/mL y de 2.10² UFC/mL en las células de levadura, respectivamente. La inclusión de 3000 ppm de A1 y de 30 ppm de A2, mejoró significativamente (P<0,05) la conversión alimenticia (11-13%) y el consumo de alimento (6-8%), al compararse con el grupo control. La ganancia de peso no fue afectada significativamente por los tratamientos.
A study was conducted to obtain and characterize the nutritional, enzymatic, and ocratoxigenic properties of enzyme additives obtained from fermentation of moist residues of commercial production of pasta, of both a monoculture of Aspergillus niger (A1) and a mixed culture (coculture) of Aspergillus niger-Saccharomyces cerevisiae (A2). The effects on productive performance parameters were assessed, during 21 d. A total of 150 broilers (Cobb-500) were used and fed with diets which included the additives A1 and A2 in the amount of 30 and 3000 ppm, respectively, using a completely randomized design. The results show that both α-amylase and glucoamylase activities in A2 were 42 and 69% higher than those of A1, respectively. The physicochemical composition of additives revealed that they are mainly composed of starch and protein. Both A1 and A2 showed a similar amylase activity (15540 and 16020 FAU/g, respectively). However, the A2 exhibited higher glucoamylase and phytase activities (U/g) 58% than the A1. The ocratoxin A levels for A1 (2.10-4 ppb) and A2 (2.10-2 ppb), respectively, were below the median lethal dose (LD50) for chickens and for the limits established by FAO/WHO. Additionally, the viability of Aspergillus niger in A1 and A2 was 3.10³ UFC/mL and of 2.10² CFU/mL in yeast cells, respectively. The inclusion of 30 ppm of A1 and 3000 ppm of A2, respectively significantly (P<0.05) improved feed conversion (11-13%) and feed intake (6-8%), when compared to control animals. The treatments did not significantly affect weight gain.
ABSTRACT
Fusarium moniliforme (FM) incidence and fumonisins (FUM) content were determined in white kernel samples of maize hybrids, harvested in farms of Guárico and Portuguesa states, Venezuela. FM incidence was estimated in subsamples placed on a malt-salt-agar medium. Values in the range of 0-15(per cent) were considered low, from 15-30(per cent) intermediate, and more than 30(per cent) high. FUM content was quantified through specific immunoassay (Fumonitest, VICAM Sci.Tech.,USA) and values above 1 ppm were considered high. The hybrids were compared using a completely randomized desing and results were subjected to analysis of variance and mean comparisons. the correlation between FUM content and FM incidence was also estimated. FM and FUM were detected in all of the 89 samples. Mean incidence of FM among hybrids ranged from 26.0 to 72.0( per cent) in Portuguesa state (PS) and from 28.7 to 55.7 in Guárico state (GS). Significant differences among hybrids were determined in farms of E1 Playón and Turén, PS, and E1 Sombrero and E1 Socorro, GS. The incidence of FM was high in all hybrids. FUM contents ranged from 0.80 to 10.00 ppm in PS, and from 1.50 to 13.00 ppm in GS. Significant differences among hybrids were found in E1 Playón, PS, and in both locations of GS. Only in Ospino, PS, the content of FUM was correlated with FM incidence. This indicates the natural occurence of FM strains with different toxigenic capabilities. The results show that Guárico and Portuguesa states are hazardous regions regarding FM and FUM in maize kernel.