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Welfare
• The concept of welfare has moved away from just providing feed, water, and a clean cage.
• We are now charged with providing for the psychological wellbeing of our animals.
• Why?• Assessment?
– Behavioral tests– Biochemical analyses
Interpreting Results• Biochemistry varies with
– Circadian Rhythm
– Social status
– Animal gender
– Observer gender
– Line or breed
Biochemistry varies with Line and Sex
Example only—don’t memorize
Comparative Biochemistry
Mice at 8 weeks of age Balb/cJ C57Female Male Female Male Units
WBC 3.24 2.86 3.48 2.62 103 cells/ulPercent Monocytes 0.80 0.90 0.70 1.40 %Percent Neutrophils 14.80 23.10 7.40 18.50 %B cells 53.43 51.06 56.13 57.80 %T cells 16.95 20.82 15.51 13.60 %
Information from the Jackson Laboratory website
Interpreting Results• Does NE increase more during breeding or
transport?
• Does corticosterone increase more during movement of home cage or seeing another rat decapitated?
• Does corticosterone increase more during the entrance of a male technician into its room or a 15-minute restraint in a plastic tube?
Gender affects on Research Results
• A recent study looked at the effects of olfactory exposure to men on stress and related analgesia in rodents– Pain levels were determined using the grimace test.– It was noted that when the observer, seated ~0.5 m away)
was male, there was a significant decrease in facial grimacing relative to no observer
– This effect was not noticed with a female observer– The effect was short-lived. Within 30 minutes, the rodent
had habituated to the presence.– It is a result of “Stress-Induced Analgesia” – It calls into question studies in which a male technician
was used to determine pain or stress levels in rodents.
Stress vs Distress (Dr. Moberg)Normal Function
Altered biological function
Pre-pathological state
Pathology
Stimulus
Stimulus
Stimulus
Relief from stimulus Stress
Distress
Stress vs Distress, An ExampleNormal Function
Altered biological function
Pre-pathological state
Pathology
Stimulus
Stimulus
Stimulus
Inability to Cope
• Breakpoint stress—no longer able to respond or adapt to stress
• Affected by– Severity– Predictability– Duration– Interval
Breakpoint Stress
• Indicators– Change in weight or body condition– Change in organ weight and size
• Hypertrophy: • Hypotrophy:
– Suppressed reproduction– Gastric ulceration– Self-mutilation– Suppressed immune function disease
Individual Response
• Same conditions don’t lead to same response in all animals.
• Don’t rely on a single indicator to identify stress.
• Always get baseline levels
• Not all stress is bad.