Standard values in the beagle dog: haematology and clinical chemistry

Dogs for Life: Beagles, Drugs, and Capital in the Twentieth Century

This article tracks the transformation of beagle dogs from a common breed in mid-twentieth century American laboratories to the de jure standard in global toxicological research by the turn of the twenty-first. The breed was dispersed widely due to the expanding use of dogs in pharmacology in the 1950s and a worldwide crisis around pharmaceutical safety following the thalidomide scandal of the 1960s. Nevertheless, debates continued for decades over the beagle's value as a model of carcinogenicity, even as the dogs became legislated stand-ins for human beings in multiple countries. Situating beagles as a biocommodity, the article calls for more sustained attention to the "political economy" of laboratory organism breeding, use, and production. The story of American commercial breeder Marshall Farms offers insight into the role of for-profit companies in contemporary laboratory animal provision, as the article makes a case for the value of a global perspective on transnational corporations as key sites of scientific practice and collaboration.

Effect of Age on Serum Chemistry Profile, Electrophoresis and Thyroid Hormones in Beagle Dogs Two Weeks to One Year of Age

Chemistry tests were conducted on serum from young Beagle dogs in order to deter mine the effect of age on these parameters. Blood was collected at regular intervals from 25 normal Beagle puppies (13 males and 12 females) at ages ranging from 2 weeks to 12 months. Serum chemistry profiles, protein electrophoresis and radioimmunoassays for thyroxine and triiodothyronine were included. Rapidly changing age related differences were observed in several parameters. Urea nitrogen, cholesterol, triglycerides, lactate dehydrogenase, thyroxine, glucose, gamma glutamyl transpeptidase, and total bilirubin values were elevated early in life, and decreased during the first 6 to 8 weeks, while alanine aminotransferase activity was low initially and increased during this period. Lactate dehydrogenase, thyroxine, gamma glutamyl transpeptidase, total bilirubin and alanine aminotransferase attained stability by 3 months, but the remaining parameters showed slight changes subsequently, gradually approaching adult values. More gradual age related changes were observed in other parameters. These included alkaline phosphatase, inorganic phosphorus and calcium values, which were higher in younger dogs, and creatinine, aspartate aminotransferase and total protein values, which were lower in younger dogs. Creatinine and aspartate aminotransferase values were stable by approximately 6 months; alkaline phosphatase, inorganic phosphorus, calcium and total protein values continued to change gradually up to 1 year.

[Toxicity by relay. III. Safety for the human consumer of the use of Carbadox, a feed additive for swine, as estimated by a 7 years relay toxicity on dogs]

To check the possible toxicity risks of the meat from swine fed with a residue producing feed additive: Carbadox, a new methodology was used. It is the "Relay Toxicity". Swine were fed with a high dose of the additive and sacrificed without any withdrawal. In such conditions meat contains a high level of residues. The frozen meat was given daily--after thawing--at 100 g or 200 g/dog to 12 beagle dogs, 6 females and 6 males, sacrificed when 87.5 months old (85 months on experiment). On these animals, no anomaly was found: on weight gain and health; on fertility and reproductive performances; on hematology and biochemical values of blood and urine; and after careful macroscopic or microscopic examinations of the animals at safrice. We were able to obtain a safety factor above 9000 when Carbadox is used at the maximum level approved 50 ppm, and the withdrawal 4 weeks before slaughtering. To conclude, the absence of anomaly allows us to confirm the safety for the human consumer when Carbadox is used as a feed additive for swine.

[Toxicity by relay. II. A method for the asessment of safety to human consumers of carbadox, a growth-promoting additive to the feed of slaughter pigs]

A toxicity by relay. II. A method for the assessment of safety to human consumers of carbadox, a growth-promoting additive to the feed of slaughter pigs. A new methodology called "toxicity by relay" has been used to assess the potential hazard to humans of incorporating an additive into animal feeds. This methodology considers a farm-reared animal as a "relay" between the food additive and the human consumer, and employs laboratory animals as "pseudo-consumers". These laboratory animals are fed throughout their entire lives with the meat or organs of the "relay" animals which have been reared on feeds supplemented with various levels of the additive. In the present study, the toxicity of carbadox was assessed in this way. In pigs, where it is used as a growth promoter, carbadox is metabolised into serveal different products, and so an assessment of its safety using traditional methods of studying the toxicity of a substance and tis known metabolites, would perhaps be subject to error. A safety factor for man, in relation to the safety factors for rats and dogs, was calculated using (a) the comparative consumption of the laboratory animals and man; (b) an assessment of the highest dosage likely to be consumed in normal circumstances compared to the laboratory dosage, and (c) the consideration that in the laboratory there is no period of withdrawal from feeding before sacrifice as is the case with animals for slaughter. Pigs were used as "relays" in the present study by supplementing their feed with carbadox. The meat and/or livers of these animals were then fed daily to (a) rats for a period of 3 generations; (b) rats for 24-25 months, and (c) dogs for 60 months. No abnormalities were observed at the termination of the experiments. We may therefore conclude that there is no hazard for the human consumer from the use of carbadox as a pig-feed additive.