Acclimation of Rodents (IACUC)

Purpose

Boston University (BU) is committed to observing Federal policies and regulations and AAALAC International standards for the humane care and use of animals. This policy describes the acclimation period for rodents. Adherence to this policy is mandatory unless a specific exception has been approved by the IACUC.

Covered Parties

This policy is applicable to all persons responsible for conducting research, teaching, training, breeding, and related activities, hereinafter referred to collectively as “activities”, involving vertebrate animals at or under the auspices of Boston University.

University Policy

In order to prevent additional stress to newly-arrived animals and to ensure transportation stress on experimental animals does not confound research data, Boston University has established the following policies for acclimation of newly arrived research rodents.

Rodents from approved vendors with defined health profiles do not require quarantine. However, researches should give recently arrived animals “a period for physiologic, psychologic, and nutritional stabilization” before their use. The stabilization time frame depends on the type and duration of animal transportation, the species involved, and the intended use of the animals.10

This policy does not address rodent quarantine.

Policies for Rodent Acclimation After Shipping

  • BU requires a 3-day (72-hour) acclimation period for rodents prior to use for any survival experiments.
  • If surgery or other major survival procedures or experiments are started on a Friday [because the animal(s) arrived the previous Tuesday], the responsible research staff must be prepared to check and care for the rodent(s) throughout the weekend (Saturday and Sunday).
  • BU allows day-of-arrival use for terminal experiments (non-survival surgery, tissue harvest). However, the principal investigator should consider the effect shipping stress may have on the experimental data.
  • Rodents acquired from colleagues at other institutions or from colleagues at another BU campus are subject to the IACUC Policy for Transportation of Rodents and ASC’s Policies on Importation of Rodents and Quarantine of Rodents. Therefore, their period of acclimation will usually extend beyond the 72-hour time limit.
  • If animals are moved into a different biocontainment level prior to study, additional acclimation time may be considered.

Factors affected by shipping stress and acclimation

Transportation stress has widespread effects on physiological systems in laboratory animals, including changes in the cardiovascular, endocrine, immune, central nervous, and reproductive systems.

These transportation stress effects are short-lived, but can confound research data if animals are used before they return to homeostasis and physiological measures return to normal.

A period of acclimation after transportation to restore homeostasis is generally suggested. Consider the following questions to establish an adequate period for acclimatization:

  • Will anticipated physiological changes confound the research to be conducted?
  • What is the length of time necessary for confounding physiological changes to normalize?

Finding Answers in the Literature

Most of the literature on the physiological impact of transportation involves agricultural animals. However, the limited literature on common laboratory animal species generally parallels changes documented in agricultural animals.

The literature documents elevated heart rate and weight loss, as well as elevated concentrations of adrenaline, noradrenaline, glucose, cortisol, free fatty acids, and β-hydroxybutyrate. Carbohydrate, protein, and lipid metabolism (both lipolysis and lipogenesis) are altered, and plasma osmolality, albumen, protein, and pack-cell volume increase. Neutrophilia and lymphopenia are also evident.

These measures generally return to baseline within one to seven days of transportation, although animals that are young, severely stressed, and have stress-sensitive genotypes may show altered physiological measures for several weeks. Other measures such as circadian rhythm and reproductive performance may take several weeks to months to normalize.1

Handling Animals

“Numerous studies demonstrate the beneficial effects of frequently handling research animals before initiation of study protocols as well as in early life.”12

“Animals habituated to the handler or which are gentled in early life show less handling stress in later life and react only to the particular experimental stimuli used in the study, whereas non-handled animals are much more likely to react to a new handler as well as to the test situation.”13

Acclimation Periods

Periods of acclimation exceeding three days may be required for certain studies. It is in the principal investigator’s best interest to ascertain how the studies undertaken are confounded by transportation stress. For example, it has been reported that subsequent to transportation:

  • Reproduction including reproductive hormones and behavior are affected for a significant period of time and affect adolescent rodents more4,5,8
  • Immunologic functions are inhibited2
  • Corticosterone levels are elevated3
  • Serum chemistry parameters are affected3
  • Fetal brain development and response to toxins6
  • Heart rate, body temperature, and activity9

Responsible Parties

Principal Investigators are responsible for ensuring adherence to this policy.

The Animal Welfare Program and the Institutional Animal Care and Use Committee are responsible for overseeing implementation of and ensuring compliance with this policy.

  1. Jennifer A. Obernier and Ransom L. Baldwin, 2007. Establishing an Appropriate Period of Acclimatization Following Transportation of Laboratory Animals. ILAR Journal 47(4).
  2. Landi, MS et al. Effects of shipping on the immune function of mice. Am J Vet Res 1982 Sep. 43(9):1654–7.
  3. Bean-Knudsen DE and Wagner, JE. Effect of shipping stress on clinicopathologic function in F344/N rats. Am J Vet Res 1987 Feb. 48(2): 306–8.
  4. Stewart J, Kolb, B. The effects of neonatal gonadectomy and prenatal stress on cortical thickness and asymmetry in rats Behav Neural Biol 1988. May, 49(3):344–60.
  5. Hayssen V. Effect of transatlantic transport on reproduction of agouti and nonagouti deer mice, Peromyscus maniculatus. Lab Anim 1998 Jan 32(1):55–64.
  6. Ogawa, T. et al Valproate-induced developmental neurotoxicity is affected by maternal conditions including shipping stress and environmental change during early pregnancy. Toxicol Lett 2007 Nov 174(1-3):18–24.
  7. Syversen E et al Temperature variations recorded during interinstitutional air shipments of laboratory mice. J Am Assoc Lab Anim Sci 2008 Jan 47(1):31–6
  8. Laroche J et al Reduced behavioral response to gonadal hormones in mice shipped during the peripubertal/adolescent period. Endocrinology 2009 Jan [Epub ahead of print]
  9. Capdevila, S et al Acclimatization of rats after ground transportation to a new animal facility. Lab Anim 2007, Apr 41(2):255–61.
  10. Guide for the Care and Use of Laboratory Animals, Eighth Edition. P. 111
  11. NRC [National Research Council], 2006. Guidelines for the Humane Transportation of Research Animals. Washington DC, National Academies Press.
  12. Conour, LA, Murray, KA and Brown, MJ 2006. Preparation of Animals for Research – Issues to Consider for Rodents and Rabbits. In Preparation of Animals for Use in the Laboratory. ILAR Journal 47(4):283–293.
  13. Tuli Js et al 1995. Stress measurements in mice after transportation. Lab Anim 29:132–138.

History

Effective Date: 05/07/2024
Next Review Date: 05/06/2027

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