The aim of this study was to compare two methods (precipitate and Friedewald) for the determination of LDL cholesterol values in cattle. Blood samples were taken from 56 cattle in early morning. In the serum LDL cholesterol levels were determined by the precipitation method and the Friedewald formula. The results were analyzed using a oneway analysis of variance. The precipitated method reported values (mg/dl) of 14.33, 0.36, 59.11, 58.75 and 11.21 for average, minimum, maximum, range and standard deviation, respectively, and by the Friedewald method values (mg/dl) were 62.04, 13.68, 156.82, 143.14 and 32.97 respectively, with significant difference between the two methods for a confidence level of 95.0%. The results indicate that the use of the precipitation method for the determination of LDL cholesterol in cattle is not recommended.

The aim of this study was to compare the direct method with the precipitation method for the determination of LDL cholesterol in a species with a metabolic HDL pattern. Blood samples were taken from 56 dairy cows early in the day. The LDL cholesterol levels were determined in the serum by both methods using commercial kits. The results were statistically analyzed using a one-way analysis of variance. The direct method reported values (mg/dl) of 46.66, 6.50, 101.83, 95.33 and 24.15 for average, minimum, maximum, range and standard deviation, respectively, and using the precipitation method values (mg/dl) of 14.33, 0.36, 59.12, 58.76 and 11.21 respectively, with a statistically significant difference between these methods for a 95.0% confidence level. The results indicate that the direct method is the most reliable for the determination of LDL cholesterol levels.

The aim of this study was to determine the levels of leptin in broilers and laying hens by using a kit designed for human samples. Fasting blood samples were collected from 80 broilers of the Cobb 500 line of 4 weeks of age (40 females and 40 males) and 86 hens of 26 weeks of age (43 Lohmann Brown and 43 Hy-line). Leptin levels were determined by an ELISA sandwich, after validation of the kit for use in commercial poultry. The mean, minimum, maximum and standard deviation values ​​of leptin for broilers were 0.61, 0.12, 3.99 and 0.10 ng/ml, respectively, without significant difference between sexes. Laying hens reported a mean, minimum, maximum and standard deviation values ​​of 0.66, 0.16, 1.83 and 0.11 ng/ml, respectively, without significant difference between lines. Similarly, no statistical difference was found between broiler chickens and laying hens. The results of the stu...

El objetivo de este estudio fue comparar dos métodos (precipitado y Friedewald) para la determinación de los valores de colesterol LDL en bovinos. Se tomaron 56 muestras de sangre de bovinos en las primeras horas de la mañana. Se determinaron los niveles de colesterol LDL en el suero mediante el método de precipitación y mediante la fórmula de Friedewald. Los resultados fueron analizados mediante un análisis de varianza de una vía. El método precipitado reportó valores (mg/dl) de 14.33, 0.36, 59.11, 58.75 y 11.21 para promedio, mínimo, máximo, rango y desviación estándar, respectivamente, y mediante el método de Friedewald se obtuvieron valores (mg/dl) de 62.04, 13.68, 156.82, 143.14 y 32.97, respectivamente, habiendo diferencia significativa entre estos métodos para un nivel de confianza del 95.0%. Los resultados indican que no es recomendable la utilización del método...

El objetivo del estudio fue comparar el método Directo con el método de Precipitación para la determinación de colesterol LDL en una especie con patrón metabólico HDL. Se tomaron muestras de sangre de 56 vacas lecheras a primera hora del día. Se determinaron los niveles de colesterol LDL en el suero mediante ambos métodos utilizando kits comerciales. Los resultados fueron analizados estadísticamente mediante un análisis de varianza de una vía. El método directo reportó valores en mg/dl de 46.66, 6.50, 101.83, 95.33 y 24.15 para promedio, mínimo, máximo, rango y desviación estándar, respectivamente y mediante el método de precipitación se obtuvieron valores (mg/dl) de 14.33, 0.36, 59.12, 58.76 y 11.21, respectivamente, habiendo diferencia estadísticamente significativa entre estos métodos para un nivel de confianza del 95.0%. Los resultados indican que el método dire...

The aim of this study was to determine the levels of leptin in broilers and laying hens by using a kit designed for human samples. Fasting blood samples were collected from 80 broilers of the Cobb 500 line of 4 weeks of age (40 females and 40 males) and 86 hens of 26 weeks of age (43 Lohmann Brown and 43 Hy-line). Leptin levels were determined by an ELISA sandwich, after validation of the kit for use in commercial poultry. The mean, minimum, maximum and standard deviation values ​​of leptin for broilers were 0.61, 0.12, 3.99 and 0.10 ng/ml, respectively, without significant difference between sexes. Laying hens reported a mean, minimum, maximum and standard deviation values ​​of 0.66, 0.16, 1.83 and 0.11 ng/ml, respectively, without significant difference between lines. Similarly, no statistical difference was found between broiler chickens and laying hens. The results of the stu...