ABSTRACT
The objective of this work was to test the hypothesis that a somatotropin (STH)-induced reduction in body fat would prolong the life span of the obese Zucker rat. Two experiments were conducted. In the first experiment, male and female, lean and obese Zucker rats were treated with STH (0 or 2 mg/d bovine STH) for 4 weeks, beginning at 7 months of age. Across phenotypes, STH treatment increased the growth rate by 159%, muscle weights by 14%, and circulating insulin-like growth factor (IGF)-1 by 23%, and decreased carcass fat by 21% (P < 0.05). The second experiment was a longevity trial to determine whether these changes in body composition would increase the life span of the obese rat. Beginning at 7 months of age, individually housed, male and female, lean and obese rats were assigned to daily STH treatments (0 or 2 mg/d). Rats were monitored daily, and sick or moribund rats were euthanized and necropsied to determine existing pathologies. The average life span of the lean rats was 661 days and was unaffected by STH treatment (639 days, NS) or gender. Average life span of the vehicle-injected obese rats (435 days) was less than that of the lean group (P < 0.001). STH treatment of the obese rats resulted in a further reduction of life span (349 days, P < 0.02). The predominant pathology observed across the treatment groups was renal disease, characterized by progressive glomerulonephropathy. Thus, although exogenous STH was able to reduce carcass lipid and to increase lean tissue mass in obese rats, there was no improvement in longevity. In contrast to the hypothesis, STH actually reduced the life span of the obese rat. It is likely that STH treatment accelerated the development of progressive glomerulonephropathy in the obese rat.
Subject(s)
Aging/physiology , Body Composition/drug effects , Growth Hormone/pharmacology , Longevity/drug effects , Obesity/physiopathology , Adipose Tissue/metabolism , Adipose Tissue/pathology , Animals , Anti-Obesity Agents/administration & dosage , Anti-Obesity Agents/pharmacology , Anti-Obesity Agents/therapeutic use , Body Weight/drug effects , Body Weight/physiology , Female , Growth Hormone/administration & dosage , Growth Hormone/therapeutic use , Longevity/physiology , Male , Models, Animal , Obesity/pathology , Rats , Rats, ZuckerABSTRACT
Compared to other laboratory animals, little is known about the use of anesthetics in birds, potentially resulting in the use of improper dosing regimens. The authors compared two commonly used ketamine combinations with isoflurane and concluded that the injectable doses were ineffective for induction of surgical anesthesia in chickens.
Subject(s)
Anesthesia, Intravenous/veterinary , Anesthetics/pharmacology , Chickens/physiology , Diazepam/pharmacology , Ketamine/pharmacology , Xylazine/pharmacology , Analysis of Variance , Anesthesia, Inhalation/veterinary , Anesthetics/administration & dosage , Animals , Blood Glucose/drug effects , Body Temperature/drug effects , Diazepam/administration & dosage , Drug Combinations , Heart Rate/drug effects , Injections, Intravenous/veterinary , Isoflurane/administration & dosage , Ketamine/administration & dosage , Respiration/drug effects , Xylazine/administration & dosageABSTRACT
Listeria monocytogenes, isolated from outbreaks in either human or nonhuman primate populations, was administered orally at doses ranging from 10(6) to 10(10) CFU. Four of 10 treated animals delivered stillborn infants. L. monocytogenes was isolated from fetal tissue, and the pathology was consistent with L. monocytogenes infection as the cause of pregnancy loss. For all pregnancies resulting in stillbirths, L. monocytogenes was isolated from maternal feces, indicating that L. monocytogenes had survived and had probably colonized the gastrointestinal tract. Antibodies and antigen-specific lymphocyte proliferation against Listeria increased in animals that had stillbirths.
