Effect of monensin and its metabolites in broiler litter on sheep consuming the broiler litter

Abstract

Two trials were conducted to determine the effect of monensin in broiler litter on sheep receiving the broiler litter in their diets. Broiler litter from chickens fed monensin as a coccidiostat, and from chickens receiving no coccidiostat, was included at a level of 30% in 2 sheep diets. In a further 2 treatments, monensin (15 mg kg-¹) was added to each of the 2 diets to give a 2x2 factorial experimental design. In the first trial, copper (20 mg kg-¹ feed) was added to the diets. These lambs were fed individually at a slightly restricted level of intake. No differences between treatments were observed in feed intake, average daily gain or efficiency of feed utilisation or in the concentrations of zinc, iron and manganese in the liver, glutathione peroxidase in erythrocytes and creatine kinase concentrations in the. plasma. Hepatic copper content and copper retention in the livers of the sheep receiving the added monensin were signficantly higher (P <0,05 and < 0,01 respectively) than in those not receiving added monensin. The aspartate transaminase and alkaline phosphatase concentrations in the plasma of these sheep were also higher (P < 0,05) than in those not consuming added monensin. In the second trial, the lambs were group-fed according to treatment and received the diets on an ad lib basis. The mean intakes of the groups receiving the diets with the added monensin, were lower than the intakes by the other groups. It was concluded that the monensin metabolites in broiler litter had no measurable effect on any of the parameters of monensin activity investigated in sheep, when such litter was included in sheep diets.