Fate of avermectin B sub 1a in lactating goats
- Merck, Sharp and Dohme Research Lab., Three Bridges, NJ (United States)
Lactating goats were administered ({sup 3}H) avermectin B{sub 1a} by 10 daily oral doses at one of three dose levels (0.005, 0.05, 1.0 mg/kg). Excreta and milk were collected daily and the total radiolabeled residues measured. After the fourth dose, maximal residue levels were observed in the excreta and milk. One day after the last dose, various goat tissues were obtained and the total radiolabeled residue was measured. Tissue residue levels were dose dependent and were less than 100 ppb for goats treated at the high dose (1 mg/day). Most of the dose (89-99%) was recovered in the feces, with < 1% recovered in the urine or milk. The levels of avermectin B{sub 1a} in the edible tissues were mostly between 70 and 95% of the total residue for all goats. The major metabolite in the edible tissues and milk was identified as 24-(hydroxymethyl)avermectin B{sub 1a}. A minor metabolite, 3{double prime}-desmethylavermectin B{sub 1a}, was also identified in the edible tissues. Both metabolites were previously identified in the corresponding tissues of rats administered avermectin B{sub 1a}. The parent and these two metabolites accounted for 85-99% of the total residue in the edible tissues, milk, and feces of the goats. The extent of tritium exchange was determined to be < 0.1% of the dose.
- OSTI ID:
- 6056859
- Journal Information:
- Journal of Agricultural and Food Chemistry; (United States), Journal Name: Journal of Agricultural and Food Chemistry; (United States) Vol. 37:6; ISSN 0021-8561; ISSN JAFCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
CLEARANCE
DOMESTIC ANIMALS
EXCRETION
FECES
FOOD
GOATS
HYDROGEN COMPOUNDS
INSECTICIDES
ISOTOPE APPLICATIONS
MAMMALS
MATERIALS
METABOLISM
METABOLITES
MILK
ORAL ADMINISTRATION
PESTICIDES
RUMINANTS
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES
WASTES