Evaluating the clinical and physiological effects of long term ultraviolet B radiation on guinea pigs (Cavia porcellus) and rabbits (Oryctolagus cuniculus)

Watson, Megan

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Description

Title

Evaluating the clinical and physiological effects of long term ultraviolet B radiation on guinea pigs (Cavia porcellus) and rabbits (Oryctolagus cuniculus)

Author(s)

Watson, Megan

Issue Date

2014-09-16

Director of Research (if dissertation) or Advisor (if thesis)

Mitchell, Mark A.

Department of Study

Vet Clinical Medicine

Discipline

VMS-Veterinary Clinical Medcne

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Vitamin D
• 25-hydroxyvitamin D3
• ultraviolet B radiation
• ultraviolet B (UVB)
• rabbit
• Oryctolagus cuniculus
• guinea pig
• Cavia porcellus

Abstract

Vitamin D is an important hormone in vertebrates. Most animals acquire this hormone through their diet, exposure to ultraviolet B (UVB) radiation and subsequent photobiochemical synthesis, or a combination thereof. The objectives for this research were to evaluate the clinical and physiologic effects of artificial UVB light supplementation on rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus) and to evaluate the long-term safety of artificial UVB light supplementation over the course of six months in these species. Twelve juvenile acromelanic albino Hartley guinea pigs and twelve juvenile New Zealand white rabbits were randomly assigned to one of two treatment groups: Group A was exposed to 12 hours of artificial UVB radiation daily and Group B received ambient fluorescent light with no UVB supplementation for 12 hours daily. Animals in both groups were offered the same diet and housed under the same conditions. Blood samples were collected every three weeks over six months to measure blood chemistry values, parathyroid hormone, ionized calcium, and serum 25-hydroxyvitamin D3 (25-OHD3) levels. Serial ophthalmologic examinations were performed at the beginning of the study and every two months thereafter. Computed tomography (CT) scans were performed at beginning and conclusion of the study to assess bone mineral density. Dual energy x-ray absorptiometry (DEXA) scans were performed at the conclusion of the study. At the end of the study the animals were euthanized and necropsied. Mean ± SD serum 25-OHD3 concentrations differed significantly in both the guinea pigs (p < 0.0001) and rabbits (p= 0.003) between animals provided supplemental UVB radiation (Guinea pig: 101.49 ± 21.81 nmol/L; Rabbit: 83.12 ± 22.44 nmol/L) and those not provided supplemental UVB radiation (Guinea pig: 36.33 ± 24.42 nmol/L; Rabbit: 39.33± 26.07 nmol/L). No significant difference in bone mineral density was noted between groups on CT scans or the DEXA scan. An increased corneal thickness in both eyes was found in guinea pigs supplemented with UVB compared to those provided ambient light (right eye [OD]: F=149.527, p<0.0001; left eye [OS]: F=30.525, p=<0.0001). There were no apparent negative clinical or pathologic side effects noted between the treatment and control animals. This study found that exposing guinea pigs and rabbits to UVB radiation long term significantly increased their circulating serum 25-OHD3 levels, and that this increase was sustainable over time. In vertebrates, vitamin D is an essential hormone that regulates many different functions in the body and can be protective against various disease conditions. Providing guinea pigs, rabbits, or other diurnal rodents, exposure to UVB may be an important husbandry consideration that is not currently recommended.

Graduation Semester

2014-08

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http://hdl.handle.net/2142/50499

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Copyright 2014 Megan Watson

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