f6098d8b__and_Use_of_Laboratory_Animals__Comments
[ID] 63 [Entry Date] 04/14/2011 at 04:17:38 PM [Affiliation] Self [Organization Name] University of Maryland, Baltimore [Organization City and State] Baltimore, MD [Comments] 
Comment 1: This new caging policy for rodents is arbitrarily defined and is not correct according to recent studies. For example, the article given below finds that "The current findings indicate that mouse housing density can be increased 50% to 100% above the current recommendations (as floor area per mouse) with no or few apparent affects on mouse overall wellbeing." The intended guide will result in the following: · No more than 4 (not the 5 currently allowed) adult mice per cage – this represents a 20% increase in cages needed over current standards · A female with litter would have to be housed individually, since there would only be 12 sq. in. remaining (63 sq in/cage – 51 sq in for mom with litter) – not "enough" space for a second adult mouse (which needs 15 sq in per these requirements). For a "standard" 2 female, one male breeding cage (which can currently remain together in a single cage as the females deliver pups and nurse them) this represents a >200% increase in cages needed over current standards. Therefore, to increase research costs without justification or scientific validity is a waste of resources, especially in such a budget restricted time. J Am Assoc Lab Anim Sci. 2009 Nov;48(6):740-53. The response of C57BL/6J and BALB/cJ mice to increased housing density. Nicholson A, Malcolm RD, Russ PL, Cough K, Touma C, Palme R, Wiles MV. The Jackson Laboratory, Bar Harbor, Maine, USA. Abstract Increased numbers of mice housed per cage (that is, increased housing density) is seen as 1 way to reduce the costs of conducting biomedical research. Current empirically derived guidelines are based on the area provided per mouse depending on body weight as documented in the Guide for the Care and Use of Laboratory Animals. The current study aimed to provide a more scientific basis for housing density by examining the response of C57BL/6J and BALB/cJ mice to increased housing density from weaning to 5 mo of age, to determine those parameters most useful for future larger-scale studies. A wide range of phenotypic characteristics--including growth rate, body composition, hematology, serum biochemistry, hormone and metabolite measurements, in-cage telemetry, behavior, and cage microenvironment--was examined at various time points. The parameters showing greatest changes were: growth rate, which was significantly reduced in animals at the highest density; adrenal gland size, the proportion of adrenal cortex, and concentration of fecal corticosterone metabolites, all of which were increased at higher densities; and anxiety and barbering, which were more pronounced at higher densities. Cage microenvironment deteriorated with increasing density, but the increases in measured parameters were small, and their biologic impact, if any, was not apparent. The current findings indicate that mouse housing density can be increased 50% to 100% above the current recommendations (as floor area per mouse) with no or few apparent affects on mouse overall wellbeing. However, weight gain, fecal corticosterone metabolite levels, and barbering differed significantly with housing density and therefore are suggested as good measures of the response to alterations in housing. Comment 2: This new caging policy for rodents is arbitrarily defined and is not correct according to recent studies. For example, the article given below finds that "The current findings indicate that mouse housing density can be increased 50% to 100% above the current recommendations (as floor area per mouse) with no or few apparent affects on mouse overall wellbeing." The intended guide will result in the following: · No more than 4 (not the 5 currently allowed) adult mice per cage – this represents a 20% increase in cages needed over current standards · A female with litter would have to be housed individually, since there would only be 12 sq. in. remaining (63 sq in/cage – 51 sq in for mom with litter) – not "enough" space for a second adult mouse (which needs 15 sq in per these requirements). For a "standard" 2 female, one male breeding cage (which can currently remain together in a single cage as the females deliver pups and nurse them) this represents a >200% increase in cages needed over current standards. Therefore, to increase research costs without justification or scientific validity is a waste of resources, especially in such a budget restricted time. J Am Assoc Lab Anim Sci. 2009 Nov;48(6):740-53. The response of C57BL/6J and BALB/cJ mice to increased housing density. Nicholson A, Malcolm RD, Russ PL, Cough K, Touma C, Palme R, Wiles MV. The Jackson Laboratory, Bar Harbor, Maine, USA. Abstract Increased numbers of mice housed per cage (that is, increased housing density) is seen as 1 way to reduce the costs of conducting biomedical research. Current empirically derived guidelines are based on the area provided per mouse depending on body weight as documented in the Guide for the Care and Use of Laboratory Animals. The current study aimed to provide a more scientific basis for housing density by examining the response of C57BL/6J and BALB/cJ mice to increased housing density from weaning to 5 mo of age, to determine those parameters most useful for future larger-scale studies. A wide range of phenotypic characteristics--including growth rate, body composition, hematology, serum biochemistry, hormone and metabolite measurements, in-cage telemetry, behavior, and cage microenvironment--was examined at various time points. The parameters showing greatest changes were: growth rate, which was significantly reduced in animals at the highest density; adrenal gland size, the proportion of adrenal cortex, and concentration of fecal corticosterone metabolites, all of which were increased at higher densities; and anxiety and barbering, which were more pronounced at higher densities. Cage microenvironment deteriorated with increasing density, but the increases in measured parameters were small, and their biologic impact, if any, was not apparent. The current findings indicate that mouse housing density can be increased 50% to 100% above the current recommendations (as floor area per mouse) with no or few apparent affects on mouse overall wellbeing. However, weight gain, fecal corticosterone metabolite levels, and barbering differed significantly with housing density and therefore are suggested as good measures of the response to alterations in housing.
Listing of Public Comments on Proposed Adoption and Implementation of the Eighth Edition of the Guide for the Care and Use of Laboratory Animals