Toxicological and pharmacokinetic research on lincomycin hydrochloride in broiler chickens and layer hens

: Tested was the activity of linkomycin hydrochloride at the rate of 820 IU/mg. The LD50 of the preparation was found to exceed 12.0 g/kg body mass at intracrop application to broiler birds. When offered with the drinking water or the feed in amounts that were 3 to 5 times higher than the therapeutic ones for broilers in the course of 45 days it did not cause mortality nor induced changes in the white and red blood cell counts, in the total protein, and in the levels of urea, blood sugar, AlT, and AcT. Neither were there any structural changes in the internal organs. Upon the single intracrop treatment of broilers with linkomycin at 50 and 100 mg/kg most of the amount introduced was established in the blood serum at the second hour and up to the 6th and 8th hour, respectively. Studies on the effect of age on the serum concentrations at this route of introduction revealed that the preparation was absorbed at higher rates in the broilers than in the layers, while with the persistence of the levels there were no essential differences. At the single oral administration with broilers in amounts of 100 mg/kg linkomycin was chiefly retained in the kidneys, liver, and lungs as well in the content of the small and large intestines. At intracrop application to layers in doses of 100 mg/kg in the course of 7 days the antibiotic was excreted with the eggs at the time of treatment and in the course of 4 days later in bacteriostatic concentrations of 0.6-5.9 micrograms/cm3.