Single intramuscular dose toxicokinetics of manganese in broiler chicks

Abstract

Aim: Manganese (Mn) produces neurobehavioral toxicity in various animal species including the young chicks. The present study examines toxicokinetics of Mn in 7-10-day old chicks after an intramuscular injection at 20 mg/kg. Materials and Methods: Samples of the blood, whole brain, liver and kidney were obtained from chicks (5/each time period) at 0 time (base-line) and then at times between 0.17 to 4 h. The concentrations of Mn in the plasma and tissues were determined by atomic absorption spectrometry. Toxicokinetic parameters of Mn were calculated from the mean metal concentrations in the plasma by a non-compartmental analysis using a Windows-based computer program. Results: Injection of Mn significantly increased the metal levels in the plasma, whole brain, liver and kidney of the chicks when compared to respective base-line control values at times 0.17 to 4 h after the injection (with the exception at 2 and 4 h in the brain). The highest concentration of Mn in the plasma and the whole brain appeared one h after the injection, whereas those of the liver and kidney appeared 4 h post-injection. The concentrations of Mn in the plasma ranged between 0.43 to 1.2 µg/ml within 0.17 to 4 h. Those of the whole brain, liver and kidney were 0.11– 0.46, 6.3–15 and 5.3–22.9 µg/g, respectively. The elimination half-life of Mn was 3.02 h with steady state volume of distribution 24.34 L/kg and total body clearances of 4.78 L/h/kg. The mean residence time of Mn was 5.09 h and its area under the plasma concentration-time curve (0- ) was 4.18 µg.h/ml. The elimination half-life of Mn from the brain was 3.12 h with an elimination rate constant of 0.22 h-1. Conclusion: The data suggest that Mn is well absorbed and rapidly distributed after an intramuscular administration in chicks and further support the reported neurobehavioral toxic effects of the metal which are observed within one h after treatment.