RESUMEN
Thirty male calves were used in a 2 X 3 factorial arrangement of treatments to determine the effects of dietary nickel and protein on performance, urease activity and tissue concentrations of nickel, iron, zinc, copper and manganese. Protein levels evaluated were 10.0, 12.25 and 14.5%, and nickel was supplemented at a level of 0 or 5 mg/kg of diet. Nickel did not affect growth during the 140-d study but tended to increase efficiency of gain in calves fed 14.5% protein. Rumen fluid urease activity was increased by nickel only in animals receiving the low protein diet. Urease activity in rumen fluid was higher in calves fed 10.0% than in animals fed 12.25% or 14.5% protein. Neither nickel nor protein affected urease activity in rumen epithelium. Increasing dietary protein resulted in increased urease in cecal digesta. Lung, liver, kidney and serum nickel concentrations were increased by supplemental nickel. A nickel X protein interaction was noted for kidney nickel. Nickel supplementation increased kidney nickel to a greater degree in calves fed 10.0% protein than in calves fed higher protein levels. Nickel supplementation reduced iron concentrations in lung, liver and muscle and manganese concentrations in muscle. Increased dietary protein decreased iron in liver and spleen but increased manganese concentrations in heart. These findings indicate that dietary protein influences responses of ruminants to nickel supplementation and relatively small increases in dietary nickel and protein can influence metabolism of other trace elements.
Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Bovinos/metabolismo , Proteínas en la Dieta/farmacología , Metales/metabolismo , Níquel/administración & dosificación , Nitrógeno/metabolismo , Animales , Glucemia/análisis , Nitrógeno de la Urea Sanguínea , Bovinos/crecimiento & desarrollo , Cobre/metabolismo , Hierro/metabolismo , Manganeso/metabolismo , Níquel/metabolismo , Necesidades Nutricionales , Distribución Tisular , Zinc/metabolismoRESUMEN
Day-old pigs were individually fed a low nickel (0.16 ppm) liquid milk-based diet supplemented with either 0, 5 or 25 ppm nickel on a dry matter basis for a 21-day period. At the end of the liquid feeding period, five pigs per treatment were killed, and the remaining five were fed a dried skim milk-based diet (0.12 ppm nickel) with similar levels of added nickel for an additional 28 days. Dietary nickel did not affect animal gain, liver cholesterol, serum protein concentrations or bacterial urease activity in the gastrointestinal tract. The addition of 5 ppm nickel to the basal dry diet reduced ammonia concentrations in the cecum by 33%. Pigs receiving the high level of nickel had decreased serum alkaline phosphatase and increased serum glucose at 49 days, compared to controls. Animals receiving 5 ppm nickel had higher liver iron and zinc concentrations than controls at 21 days but not at 49 days. Control pigs had lower kidney and lung nickel concentrations than animals receiving 5 ppm nickel at 21 days but not at 49 days. Increasing dietary nickel from 5 to 25 ppm resulted in increased concentrations of nickel in serum, kidney, lung, spleen and muscle. These results suggest that 0.12-0.16 ppm nickel is adequate for growth of neonatal pigs fed milk-based diets. However, additional nickel may improve the iron and zinc status of the young pig.