Development of a method for forced oral administration of xenobiotics in shrimp

ABSTRACT:  Xenobiotics such as oxytetracycline and oxolinic acid need to be given orally to aquatic animals to determine their absorption, distribution and elimination. Here, we describe a method for giving xenobiotics to giant tiger prawn Penaeus monodon. A histological examination revealed serious hindgut diarrhea. This appeared to be caused by a high concentration of oxolinic acid (50 mg/kg body weight) but not oxytetracycline concentration (50 and 100 mg/kg body weight). Therefore, doses of oxolinic acid and oxytetracycline were reduced to 5–10 mg/kg to avoid the problem of hindgut diarrhea. A 1-mL syringe fitted with a feeding needle was used to inject medicated feed paste containing oxytetracycline or oxolinic acid through the mouth into the stomach. No disgorging of the medication was observed during the experiment. The maximum concentrations (Cmax) of oxytetracycline and oxolinic acid were proportional to the dose. Our method is suitable for studies of the absorption, distribution, metabolism and elimination of xenobiotics in shrimp.