Effect of Bedding Substrates on Blood Glucose and Body Weight in Mice.

Differences in cage microenvironments may contribute to variation in data and affect the outcome of animal studies involving metabolic diseases. To study this, we compared the effects 3 types of bedding-corncob bedding, hardwood bedding, and hardwood bedding plus a cardboard enrichment item-on baseline fasting and nonfasting blood glucose and body weight in mice. Mice housed on corncob bedding showed significantly higher fasting blood glucose than did mice housed on hardwood bedding, with or without the enrichment item. None of the groups showed an effect of bedding type on nonfasting blood glucose levels or body weight. This information informs the choice of bedding substrates for studies that measure fasting blood glucose and potentially mitigates a variable that could confound research outcomes.

Phenotype of cloned mice: development, behavior, and physiology.

Cloning technology has potential to be a valuable tool in basic research, clinical medicine, and agriculture. However, it is critical to determine the consequences of this technique in resulting offspring before widespread use of the technology. Mammalian cloning using somatic cells was first demonstrated in sheep in 1997 and since then has been extended to a number of other species. We examined development, behavior, physiology, and longevity in B6C3F1 female mice cloned from adult cumulus cells. Control mice were naturally fertilized embryos subjected to the same in vitro manipulation and culture conditions as clone embryos. Clones attained developmental milestones similar to controls. Activity level, motor ability and coordination, and learning and memory skills of cloned mice were comparable with controls. Interestingly, clones gained more body weight than controls during adulthood. Increased body weight was attributable to higher body fat and was associated with hyperleptinemia and hyperinsulinemia indicating that cloned mice are obese. Cloned mice were not hyperphagic as adults and had hypersensitive leptin and melanocortin signaling systems. Longevity of cloned mice was comparable with that reported by the National Institute on Aging and the causes of death were typical for this strain of mouse. These studies represent the first comprehensive set of data to characterize cloned mice and provide critical information about the long-term effects of somatic cell cloning.

A novel approach for documentation and evaluation of activity patterns in owl monkeys during development of environmental enrichment programs.

Documenting and evaluating the appropriateness of environmental enrichment programs has posed a challenge to many institutions. This paper describes a method for documenting and evaluating activity patterns for developing an environmental enrichment program. A colony of owl (or night) monkeys (Aotus lemurinus griseimembra) at the University of Hawaii were videotaped using infrared sensitive cameras and the duration and frequency of numerous activities were scored using an ethological analysis software program (Hindsight). A number of activity patterns could be observed by using this method, and a baseline was established for the current environmental enrichment for this colony. Videotaping and computer analysis is a convenient method for documenting and objectively evaluating activity patterns for use in the development of environmental enrichment programs for captive primates and other species.

Elimination of an Infestation of Rat Fur Mites (Radfordia ensifera) from a Colony of Long Evans Rats, Using the Micro-dot Technique for Topical Administration of 1% Ivermectin.

Micro-dot delivery of 1% ivermectin was used in an effort to eliminate an infestation of rat fur mites (Radfordia ensifera) from a conventionally housed colony of Long Evans rats. The colony was used for breeding as well as for behavioral testing. A micropipette was used to apply a 1% solution of ivermectin (2 mg/kg of body weight) to the skin on the dorsal aspect of the shoulder. Three treatments were applied at approximately 2-week intervals. All rats in the colony were treated. However, to avoid toxicity to neonates, nursing females and their pups (control group) received mineral oil in lieu of ivermectin until after weaning, at which time they also were treated with ivermectin. During the treatment phase, skin scrapings were used to detect mites. Control rats remained positive for fur mites when treated with mineral oil. After 3 applications of ivermectin, all rats were found to be free of mites. During the posttreatment phase, skin scrapings, dorsal tape tests, and a washing method were performed on euthanatized rats to detect mites. Rats tested up to 129 days (18 weeks) after ivermectin treatment were still free of mites. In a breeding colony composed of rats of various sizes and ages, micropipette delivery of ivermectin allowed for accurate dosing to eliminate fur mites, while preventing inadvertent toxicosis. We did not detect obvious adverse effects on the breeding program or on the behavioral studies in which these rats were subsequently used, nor did we detect morbidity or mortality associated with ivermectin administration.