Housing/Husbandry Flashcards
1
Q
List common caging material in order of decreasing cost and durability.
A
Polycarbonate, polypropylene, polystyrene.
2
Q
Which caging component is disposable?
A
Polyethylene
3
Q
How much food and water does a mouse ingest per day?
A
Food: 3-5 g/day
Water: 6-7 mL/day
4
Q
What difference exists between outbred and inbred mice concerning rate of gain and adult size?
A
Outbred mice heavier at maturity and gain weight faster.
5
Q
What is a benefit and risk of irradiated diets?
A
While they are virtually free of live micro-organisms, there is the risk of radio-resistant bacteria.
6
Q
What is unique to autoclavable diets?
A
They are higher in heat-labile nutrients.
7
Q
What is the approximate percentage of diet components?
A
Carbs: 45-60%
Protein: 20-25%
Fat: 5-12%
Fiver = 2.5%
8
Q
What are the two types of stainless steel? How do they differ? Which has superior corrosion resistance? Why?
A
304 and 316. Vary in amount of chromium and nickel in alloy. Molybdenum in 316 increases corrosion resistance.
9
Q
Generally, how do caging polymers differ?
A
Resistance to chemicals and heat, impact strength, and cost
10
Q
Describe polycarbonate. It is autoclavable to what temperature?
A
Clear, rigid plastic with high impact strength. Autoclavable to 250F (121C)
11
Q
Describe high-temp polycarbonate.
A
Clear plastic with slight tint. Similar to polycarbonate but autoclavable to 270C (132C)
12
Q
Describe polysulfone/polyethersulfone.
A
Clear, rigid plastic with slight tint. High impact strength, autoclavable to 270C.
13
Q
What is polyethylene terephthalate used for?
A
Disposable caging.
14
Q
What is BPA? Where is it found?
A
Bisphenol A. Released from polycarbonate cages and bottles, to a lesser degree from polysulfone components.
15
Q
What causes BPA release?
A
Either un-polymerized constituent or as a result of degradation. Hydrolysis of polymer at high temp but also releases at room temp as cages age.
16
Q
What is the concern regarding BPA?
A
Sufficient doses act as an endocrine-disrupting chemical. Functions similar to 17B-estradiol.
17
Q
What is BPS? From where and how is it produced?
A
Bisphenol S. From polysulfone. Polysulfone is produced by a dimerization of BPA and diphenyl sulfone. Breakage of the bonds between them generates BPS.
18
Q
What activities result in BPS release? Why is this concerning?
A
Damage and heating of polysulfone cages and bottles. Can contaminate cage washer water and internal surfaces, which can cross-contaminate intact cage surfaces. Sufficient doses act as endocrine-disrupting chemical with function similar to 17B-estradiol.
19
Q
Define thermoneutral zone. What is the TMZ of mice and rats?
A
Ambient temperature range where thermoregulation occurs without the need to increase metabolic heat production or activate heat loss mechanisms.
Mouse: 79-93F
Rat: 79-86F
20
Q
Who developed the static microisolator cage with a filter top? When?
A
Robert Sedlacek, 1982
21
Q
Where does air exchange occur primarily in static microisolator cages?
A
At cage-lid interface, not filter.
22
Q
What does an increase in macroenvironmental temperatures do to microenvironmental relative humidity?
A
Reduces relative humidity in the cage.
23
Q
When were IVCs developed?
A
Late 1980s, 1990s
24
Q
What size is the filter on top of IVCs?
A
0.2 micron
25
What is air speed in an IVC?
Less than 0.2 m/sec
26
What does HEPA-filtered exhaust air or direct-ducting of IVC racks to room exhaust reduce?
Reduces exposure of personnel to allergenic particulates, bacterial contamination of MaE, and room odor.
27
28
What air quality standards are recommended in the cage prior to cage change?
NH3 <25 ppm
CO2 <5000 ppm
Intracage air speed <50 lfpm
29
How can IVC racks be gas sanitized?
Paraformaldehyde, chlorine dioxide, and vaporized hydrogen peroxide
30
What is the difference between Tecniplasts ISOcage N and ISOcage P?
N = For bio-contaiNment
P = For bio-exclusion
31
What are disposable cages made of?
Polyethylene terephthalate (PET)
32
What is a MADU? Describe.
Mass air displacement unit. Unidirectional laminar flow, positive or negative. Class 100 air = No more than 100 particles 0.5 micrometers or larger per cubic feet of air. Replaced due to inefficiency, lack of operator protection.
33
What do BSCs offer that MADU do not?
Product and personnel protection.
34
Describe a Class I BSC.
No product protection, like a laminar flow hood.
35
Describe a Class II BSC.
Product and personnel protection. Differs in amount of recirculated air.
A2 = 70%; B1 = 50%; B2 = 0%
36
Describe a Class III BSC.
BSL-4 use. Enclosed cabinet. Look like isolators.
37
Describe a changing station.
HEPA filtered air above work surface provides product protection if sashes positioned correctly. Much of the air is captured and HEPA filtered below the work surface before release to room. Not suitable for use with hazards. Often open on both sides.
37
Mechanical cage washers rely on a combination of what two factors?
Temperature and duration/time to result in cumulative heat factor.
37
Sanitation of cage is best achieved using mechanical washers at temperatures in excess of what?
180F
38
What was the old standard for mechanical cage washers?
180F for 3 minutes in the rinse cycle. Kills vegetative bacteria in 1 second.
39
What chemicals may be used in a cage washer?
Alkaline or acidic detergents. Organic or inorganic acids (Descaling and demineralization). Neutralizers.
40
How is the specific chemical to be used in a cage washer determined?
Nature of soil to be removed. If water is hard or soft. Regulatory requirements for waste water effluent to be neutral pH.
41
Do cage washers require chemicals? Why might a facility not use chemicals?
No. Sanitation can be accomplished by heated water and spray/agitation alone.
Chemical residues can adversely affect animals and may reduce stability and longevity of thermoplastic materials.
42
Municipalities routinely analyze water quality and contaminants in compliance with what Act?
Safe Drinking Water Act overseen by EPA
43
What does filtering of water include?
Captures particulates > 5 micrometers. Activated carbon reduces organic contamination.
44
Describe reverse osmosis.
Most common system when high quality water needed. Water flows through ultrafiltration membrane under pressure. Up to 99% of inorganic compounds, dissolved ions, organic compounds, heavy metals, and microorganisms removed in filtrate.
45
What can occur to the membrane used for RO?
Foul with organic matter, affecting efficiency and supporting bacterial growth. May accumulate scale if used to purify hard water.
46
UV lamps for disinfecting emit what light?
UV rays at 254 nm
47
What factors impact effectiveness of UV lamps? What maintenance must be performed?
Dosage = Intensity and exposure time length.
Intensity decays with use - Clean glass tubes regularly and replace
48
How does ozone clean water? What does it require?
Oxidizes microorganisms and organic contaminants. Requires a ozone generator and system to diffuse the ozone into the water.
49
What does steam processing of water remove?
Vegetative bacteria, bacterial spores, fungi, and viruses.
50
Describe autoclaving for water processing.
Destroys microorganisms. Endotoxins and other contaminants remain. Usually done in filled cage bottles.
51
What is the most common additives to water? Describe their use.
Hydrochloric acid OR chlorine.
Used to reduce bacterial growth. Added to reservoir (bottle) or water distribution system. Commonly used for ID strains.
52
Historically, what compounds have been added to water?
Sulfuric acid and tetracycline.
53
Water with hydrochloric acid is acidified to what pH? Why?
pH of 2.5 to 3. pH below 3 bactericidal to Pseudomonas and other gram-negative bacteria. pH of 2 results in reduced weight gain and water consumption, low splenic weight, and reduced number of bacterial species in gut.
54
How must acidified water be provided? Why?
In plastic polymers of type 316 stainless steel. Stainless steel w/o molybdenum (304), copper, and brass will corrode.
55
Is hydrochloric water shelf stable?
Acidification temporally stable in noncorrosive containers such as plastic carboys.
56
Why is chlorine added to water?
Reduce bacterial contamination, viral contamination, and control bacterial growth and biofilm in water distribution systems.
57
What is the additive used for chlorine? At what pH is it most effective?
Sodium hypochlorite. pH of 5-7
58
What concentration of chlorine is safe?
Concentrations <10 ppm. Palatability and reduced water consumption may affect effectiveness at high concentrations.
59
What is the recommended concentration for chlorinated water?
0.5-10ppm. P. aeruginosa, the cause of opportunistic infections in ID rodents and one of the most chlorine-tolerant of enteric bacteria, can be cultured at concentrations of less than 1ppm.
60
Per one report, what is the ideal concentration of chlorine in drinking water to eliminate P. aeruginosa and reduce the carriage of the organism in mice?
6-8ppm. Provided in water bottles changed weekly.
61
Is chlorine shelf stable?
Off-gases, especially if system permits contact with air. Reacts with organic matter and other oxidizable contaminants. Dissipates in water bottles. 3ppm decrease in concentration over 7 days.
62
Chlorine is problematic in water distribution systems coated with bacteria-generated biofilm. How should the proportioning system be set up?
To deliver at least 2ppm at the furthest point of consumption.
63
Why does RO water require less chlorine to attain the desired concentration?
Lack of organic contaminants.
64
When analyzing a sample for chlorine concentration, how should the sample be treated?
Tested immediately w/o exposing to oxidizing sun/UV light, agitation, or exposure to air.
65
Chlorination of water containing organic contaminants can generate what?
By-produce trihalomethanes, such as chloroform.
66
What concentration of chlorine is used to disinfect racks, lixits, and manifolds?
Up to 50ppm
67
Chlorine should not be added to water below what pH? Why?
5.0, as chlorine will present as a gas and will damage silicon seals in drinking water lixits.
68
What can be one of the most time- and labor-intensive components of rodent husbandry?
Provision of water.
69
What can be created in glass water bottles after autoclaving?
Silicone
70
What are the two types of stoppers? Which is more resistant to degradation by repeat autoclaving? What minerals can leach into the water?
Siliconized (black) rubber and synthetic (green) neoprene. Neoprene more resistant.
Zinc, copper, magnesium, and iron can leach.
71
What is the function of the lixit shield?
Prevents bedding from entering the valve.
72
What do automatic watering systems require? What do they provide?
Pressure reducing station. Provides water at low pressures, as low as 3psi for rodents. May be equipped to detect and control substantial leaks.
73
How are automatic watering systems maintained to prevent bacterial accumulation?
Flushing with higher pressure water on preplanned schedule.
74
Biofilms on luminal surfaces protect bacteria from high pressure and chemical additives. How can biofilms be managed?
Avoid dead ends in system, flush rack tubing with sodium hypochlorite after cycling through rack washer, and autoclave rack.
75
Describe most lab diets.
Made from natural ingredients.
Nutritionally complete.
Processed whole grains and commodities.
Subject to limited refinement.
76
How are most commercial diets produced? Describe each.
Pelleting - Most efficient. Highest energy per unit and higher density. Typical feed fed to rodents and rabbits. Involves heat and pressure which reduces bacterial and fungal loads in natural ingredients
Extruded - Less dense, less hard.
77
What are the advantages and disadvantages of powdered meal diets?
Permits incorporation of additives, but tend to cake and be wasted.
78
Formulation of natural ingredient rodent diets vary principally in what?
Protein and fat content
79
What are the advantages and disadvantages of high fat diets?
High fat (up to 11%) supports breeding, gestation, and lactation but accumulation of intra-abdominal fat due to chronic use of high fat diet may shorten reproductive lifespan.
80
Describe closed formula diets.
Closed formula - Individual components of diet and their proportions not specified.
Guaranteed analysis is provided. Permits ingredients to change in association with commodity prices.
Most natural ingredient diets are closed formula
81
Describe open formula diets.
Have established/known ingredients/percent by weight formulation. NIH-07
82
What are the phytoestrogens of concern? Where are they typically found? How are feed manufacturers avoiding them?
Isoflavones diadzein and genistein. Found in protein sources, such as soybean meal and alfalfa. Using casein instead.
83
What are purified diets?
Formulated from refined ingredients. Useful when altering the nutritional content of a diet of when compounding with additives. AIN-76
84
Describe chemically defined diets.
Formulated with chemically pure compounds and are utilized when altering a specific nutritional dietary component.
Highest degree of control, but very expensive. Diet fixed at time of manufacturing. Used in germ free studies or low antigen studies.
85
What are autoclavable diets enriched with? How might they otherwise be processed?
Enriched with heat-labile nutrients thiamin, vitamins A and E, patothenic acid, pyridoxine, and B12. May also be coated with silicon dioxide in soybean oil to reduce clumping and adherence due to pellet swelling with exposure to steam.
86
What is a concern of excessive sterilization of feed?
Depletes nutrients and causes pellets to become excessively hard as a result of polymerization of feed constituents. May produce acrylamide
87
Describe gamma-irradiation of diets.
Have largely replaced the use of autoclaved diets. Less processing after receipt and not subject to effects of heat and moisture.
88
How are gamma-irradiated diets processed?
10 to 40 kGray (1-4 Mrad) from a cobalt source. Exposure of individual bags varies with position in the load.
89
Are gamma irradiated diets sterile?
No, but bacterial and fungal loads markedly reduced to less than 100 bacteria or fungi per gram of feed.
90
Is irradiation effective against viruses?
Purported to be ineffective against some viruses due to insufficient exposure, but many institutions report elimination of MPV infections.
91
What might "off the shelf" specialty feeds contain?
Fenbendazole, TMS, or doxycycline
92
Describe certified diets.
Formulated to meet requirements of FDAs GLP. Analyzed and certified to contain no more than established max levels of contaminants: Heavy metals, chlorinated hydrocarbons, organophosphates, aflatoxins
93
At what temperature and humidity are natural ingredient diets maintained? Specialty diets?
Natural: Temp less than 70F, RH less than 50%
Specialty: 39-40F
94
What does cool storage of diets prevent?
Rancidity in which unsaturated fats and lipids are oxidized and converted into hydroperoxides, which break down into volatile aldehydes, esters, alcohols, ketones, and hydrocarbons. Produce a bad odor and taste.
95
What is the shelf life of feed?
Most 180 days, some up to 9 months. Specialty diet may have a shorter half life of 90 days, especially if high in fat content.
96
What is hardwood bedding?
Aspen, beech, birch, maple.
97
What is softwood bedding? Why is this bedding avoided?
Pine or cedar. Avoid as volatile amines alter hepatic microsomal enzyme concentrations. Other volatile chemical components are carcinogenic.
98
What size of corncob bedding is typically used? How does it impact cage parameters?
1/4 or 1/8. Inhibits accumulation of NH3.
99
What are disadvantages of corncob bedding?
Fungal growth if not autoclaved or irradiated.
Abrasive with foot lesions in ID animals.
Off gassing of acetic acid due to decay of organic matter.
Density does not support nest building.
Mice may eat when fasted.
100
What are advantages and disadvantages of cellulose bedding?
More expensive than hardwood, but good nest building characteristics.
101
What is Alpha-dri bedding made from?
Cellulose fiber
102
What is certified bedding?
Specific toxic environmental contaminants are measured to assure that they do not exceed max permissible concentrations. For GLP Studies.
103
Why are Nestlets avoided with nude or hairless strains?
Fibers can impact in the conjunctival sac, causing conjunctivitis.
