Search

The use of CO(2) inhalation with different gas chamber fill rates has not been evaluated for euthanasia in commercial meat rabbits. Our objectives were to evaluate the behavioral and physiologic responses of rabbits (pre-weaned to adult) when exposed to gradual- and fast-fill rates of CO(2), and to determine the time to onset of insensibility and death. Cull rabbits (n = 81) were randomly assigned to either a gradual-fill chamber displacement rate of 28% volume change/min (n = 42) or a fast-fill chamber displacement rate of 58% volume change/min (n = 39). The fast-fill rate resulted in a more rapid loss of sensibility at a lower CO(2) chamber concentration and in a faster death than for gradual-fill. There were minimal differences in behavioral responses between fill rates with no clear signs of distress. These findings indicate that CO(2) at the studied displacement rates is suitable for commercial meat rabbit euthanasia.

Practical implementation of the 3Rs at national and regional levels around the world requires long-term commitment, backing, and coordinated efforts by international associations for laboratory animal medicine and science, including the International Association of Colleges of Laboratory Animal Medicine (IACLAM) and the International Council for Laboratory Animal Science (ICLAS). Together these organizations support the efforts of regional organization and communities of laboratory animal science professionals as well as the development of local associations and professional colleges that promote the training and continuing education of research facility personnel and veterinary specialists. The recent formation of a World Organization for Animal Health (OIE) Collaborating Center for Laboratory Animal Science and Welfare emphasizes the need for research into initiatives promoting laboratory animal welfare, particularly in emerging economies and regions with nascent associations of laboratory animal science.

In North America, the biomedical research community faces social and economic challenges to nonhuman primate (NHP) importation that could reduce the number of NHP available for research needs. The effect of such limitations on specific biomedical research topics is unknown. The Association of Primate Veterinarians (APV), with assistance from the Centers for Disease Control and Prevention, developed a survey regarding biomedical research involving NHP in the United States and Canada. The survey sought to determine the number and species of NHP maintained at APV members' facilities, current uses of NHP to identify the types of biomedical research that rely on imported animals, and members' perceived trends in NHP research. Of the 149 members contacted, 33 (22%) replied, representing diverse facility sizes and types. Cynomolgus and rhesus macaques were the most common species housed at responding institutions and comprised the majority of newly acquired and imported NHP. The most common uses for NHP included pharmaceutical research and development and neuroscience, neurology, or neuromuscular disease research. Preclinical safety testing and cancer research projects usually involved imported NHP, whereas research on aging or degenerative disease, reproduction or reproductive disease, and organ or tissue transplantation typically used domestic-bred NHP. The current results improve our understanding of the research uses for imported NHP in North America and may facilitate estimating the potential effect of any future changes in NHP accessibility for research purposes. Ensuring that sufficient NHP are available for critical biomedical research remains a pressing concern for the biomedical research community in North America.

Whether social isolation of adult rats under standard laboratory conditions produces significant long-term alterations in behavior and physiology is unclear. In the present study, male Sprague-Dawley rats were singly or paired-housed for 10 wk. During this period, they were tested for acquisition, extinction, and reacquisition of heroin (0.3 mg/kg)-conditioned place preference. Fecal corticoid metabolite levels were analyzed several times throughout the period of housing, and food consumption and body weight were monitored. During place conditioning, heroin induced a significant increase in locomotor activity in both singly and pair housed rats, and the resulting place preference was similar in both groups. However, singly housed rats showed increased motor reactivity to heroin on reconditioning after extinction and displayed significant reacquisition of conditioned place preference, compared with pair-housed animals. Over the 10-wk period of the study, there were no differences in body weight or food consumption between groups. Mild significant increases in relative adrenal gland weight and decreases in relative brain weight were noted in singly housed animals compared with those paired. Significant decreases in nocturnal fecal corticoid metabolite output were noted in both groups, with loss of circadian variation in fecal corticoid levels over the course of the study. These data suggest that male Sprague-Dawley rats, irrespective of single or pair housing, develop reduced hypothalamic-pituitary-adrenal axis activity over time under standard laboratory housing conditions. Single housing can enhance both this effect and sensitivity to the stimulatory and rewarding actions of heroin after withdrawal.

The effect of chronic daily orogastric gavage with water (5 mL/kg) on behavior and physiology was evaluated in male Sprague-Dawley rats. Treatment groups included: unmanipulated control, restraint control, dry gavage, and gavage, with all rats singly housed (n = 9 or 10 per group). In addition, a group of pair-housed rats (n = 18) was included to determine whether social housing affected response to gavage. Weekly body weights and food consumption were recorded as well as use of a nylon chew toy for enrichment. Feces were collected biweekly at the end of the light and dark phases for fecal corticoid metabolite determinations. After 28 d of treatment, animals underwent conditioned place preference testing to evaluate sensitivity to motivational properties of the anxiolytic drug chlordiazepoxide (5.6 mg/kg SC). Brain and paired adrenal gland weights were collected at necropsy. Week 2 total fecal corticosterone levels were elevated in all groups and attributed to a fire alarm accidentally tripped during building renovations. No differences occurred in body weight or food consumption between any groups. All groups used a nylon chew toy given for enrichment and demonstrated mild preference for the drug-associated chamber. Fecal weights and corticoid metabolite levels were similar between all groups at week 4 and showed normal diurnal variation. No biologically significant variations were noted in brain or paired adrenal gland to body weight ratios. We conclude that orogastric gavage of aqueous solutions at 5 mL/kg does not negatively affect the welfare of laboratory rats acclimated to handling.

A 1.5-year-old female rabbit (doe) was presented with a 3-day history of lethargy, anorexia, and mild facial swelling. The animal died shortly after examination and severe, acute hemorrhagic pneumonia was noted grossly. An alphaherpesvirus consistent with leporid herpesvirus-4 was isolated and characterized from this animal. This is the first confirmed report of the disease in Canada.