Behavioral effects of acute manganese chloride administration in chickens

The behavioral effects of manganese chloride at 20 and 40 mg/kg, subcutaneously (sc), were examined in 1-mo-old broiler chickens using the open-field (5 min) and tonic immobility tests. In a separate experiment, chickens were subjected to a pharmacological challenge with the anesthetic combination of xylazine-ketamine following manganese chloride pretreatment at 50 mg/kg, sc. Manganese at 40 mg/kg significantly decreased jumping attempts of the chickens in the open-field test 30 min after the injection when compared with the control (saline) group. Both manganese treatments significantly increased the tonic immobility response of the chickens in a dose-dependent manner in comparison with the control group. Pretreatment with manganese chloride (50 mg/kg, sc) significantly increased the duration of sleep, decreased the latency to onset of analgesia, and increased the duration of analgesia in chickens treated with the anesthetic xylazine-ketamine mixture when compared with the saline control group. The respiratory rate of all anesthetized chickens significantly decreased from respective preanesthetic (time 0) values during the 60-min observation period after injection of the anesthetic. However, 60 min after the anesthetic injection, the respiratory rate of the manganese-treated group was significantly lower than that of the control group. The data suggest a depressant action of acute manganese chloride treatment in chickens.