No abstract

A study was conducted to evaluate the effects of feeding salinomycin at the recommended prophylactic level, and at 2 and 3 times this level, to finishing male broilers (d 21 to 38). Four treatment groups were given the experimental diets containing 0, 60, 120, or 180 parts per million (ppm) salinomycin from d 21 to 38. Performance, relative organ weights, selected serum enzymes, and salinomycin residues in liver, muscle, and serum were determined. Salinomycin supplementation had no effect on body weight, feed intake, or feed conversion, and caused no overt signs of toxicity. After a week of being fed the salinomycin diets, the serum activity of aspartate aminotransferase was significantly increased in chickens fed 180 ppm compared with controls. These birds also showed microscopic lesions in breast and thigh muscles, but not in cardiac muscle. Salinomycin residues were not detected by high-performance liquid chromatography coupled to tandem mass spectrometry in liver or muscle samples from the birds fed 0, 60, or 120 ppm salinomycin. However, chickens fed 180 ppm salinomycin had detectable levels in liver and muscle above the maximum residue level of 5 μg/kg established by the European Union. All birds fed salinomycin had salinomycin in their sera with levels ranging from N.D. (not detected) in the controls to 24.4 ± 7.9, 61.4 ± 18.9, and 94.5 ± 9.1 μg/L for salinomycin dietary levels of 60, 120, and 180 ppm, respectively. Serum salinomycin concentration was linearly related with salinomycin content in feed (y = 0.584x - 10, r2 = 0.999). The results showed that even at 3 times the prophylactic level, salinomycin does not induce clinical toxicosis or mortality. No salinomycin residues were found in edible tissues at the recommended dietary level or at 2 times this level. However, salinomycin was detected in serum regardless of the dietary level. A simple method for salinomycin determination in serum is described which can be used as a marker of exposure and/or to predict levels in the diet.

Lutein and zeaxanthin are the major xanthophyll pigments found in corn kernels. These pigments provide the orange-red color of the broiler chicken skin and of the egg yolk. Therefore, knowing the corn xanthophyll content is important for the poultry feed producer. The objective of this study was to determine the lutein and the zeaxanthin content in corn cultivated in Colombia and in corn imported to Colombia from the United States, Argentina, and Brazil. Large differences in total lutein plus zeaxanthin content were found among the corn samples analyzed, with the highest mean level found in Colombian corn (2,758µg/100g), followed by Argentina (1,861µg/100g), United States (1,041µg/100g) and Brazil (947µg/100g). Large differences in lutein plus zeaxanthin content were also found among different corn hybrids cultivated in Colombia. Differences among geographical regions might be due to differences in UV-B radiation or in the light hours received by the crop during its growth. The differences among different corn hybrids might probably be due to genetic differences. Corn growers might be interested in cultivating hybrids higher in lutein and zeaxanthin as these pigments are very important in poultry production and human eye health.

Este estudio evaluó posibles diferencias en el rendimiento zootécnico y los parámetros de calidad del huevo en gallinas ponedoras y pollos de engorde alimentados con dietas formuladas con maíz producido en Colombia o maíz importado de los Estados Unidos. Para el ensayo con gallinas ponedoras, se utilizaron 80 gallinas Hy-Line Brown de 24 semanas de edad que se distribuyeron aleatoriamente en dos tratamientos, cada uno con 40 aves enjauladas individualmente. Las dietas contenían 56,7% de maíz y se proporcionó ad libitum durante 20 semanas. Para el ensayo con pollos de engorde, se utilizaron 352 pollos Ross 308 AP machos de un día de edad que se distribuyeron aleatoriamente en dos tratamientos, con 8 réplicas de 22 aves cada una. Las dietas contenían 51,0% (iniciador) a 59,6% (finalizador) de maíz y se proporcionaron ad libitum durante 35 días. Durante las 20 semanas experimentales del ensayo con las ponedoras se observó una tendencia a un mayor peso del huevo (p=0,06) en las gallinas alimentadas con la dieta que contenía maíz nacional (61,4 vs. 59,9 g), acompañada de una conversión alimenticia ligeramente inferior (1,95 vs.1,97). En cuanto a la calidad del huevo, el color de la yema mostró valores más altos (p < 0,01) para los huevos de las gallinas alimentadas con maíz nacional en las semanas 4 y 12, pero más bajos en la semana 20. Las unidades de Haugh fueron significativamente más altas (p= 0,002) en los huevos de las aves alimentadas con maíz nacional (106 vs. 102). El ensayo con pollos de engorde mostró una conversión alimenticia acumulada significativamente menor (p=0,04) para los pollos alimentados con la dieta que contenía maíz nacional en comparación con los alimentados con el maíz importado (1,37 vs. 1,42). El rendimiento en canal para la pechuga fue significativamente mayor (p < 0,01) en los pollos alimentados con el maíz importado (27,9% vs. 26,3%). Los resultados de estos dos ensayos mostraron algunas diferencias en los parámetros de producción en gallinas y pollos de engorde que favorecieron el uso de maíz nacional en comparación con el maíz importado. Sin embargo, se requieren más estudios para determinar si estas diferencias se observan en ciclos de producción completos (gallinas ponedoras) e investigar posibles diferencias utilizando como modelo experimental otras especies animales.

Background: Corn is, quantitatively, one of the most important world crops (ranking second only after wheat) and a key ingredient in animal feeds. Objective: to assess and compare corn quality, mycotoxin content, chemical composition and apparent metabolizable energy (AME) of domestic and imported corn. Methods: Grain quality (USDA grading system) was determined in 30 samples of domestic and 21 samples of imported corn. From each origin, 15 samples were subjected to proximal analysis and 10 were used to determine fatty acid composition. Mycotoxin analysis was conducted on 30 samples of domestic and 23 of imported corn. Results: six of the 30 domestic samples corresponded to US1 grade (highest quality) vs. none of the imported. In the “sample grade” category (lowest quality), 10 and 6 samples corresponded to imported and domestic corn, respectively. Soybeans were found as contaminant in 15 of the 21 imported corn samples. Aspergillus spp. mycotoxins such as ochratoxin A were not detected, and aflatoxins were found in only a few samples at very low levels. Fusariotoxins such as deoxynivalenol and zearalenone were found in 61 and 43% of imported samples, respectively, but in none of the domestic samples. Domestic corn had lower carbohydrate content compared with imported corn (85.4 vs. 86.7%), but higher crude fat (3.8 vs. 3.1%). The AME values for domestic and imported corn were 3,697 and 3,378 kcal/kg, respectively. The fatty acid profiles from both corn types were similar. Conclusion: This study found significant differences between locally-grown and imported corn, particularly in terms of crude fat, AME content, fusariotoxins, and contaminant seeds (soybeans). These findings suggest that locally-grown corn might have nutritional and toxicological advantages over corn imported from the United States.