topic 3: Bedding/Feed Flashcards
1
Q
essential nutrients
A
- cannot be synthesised in sufficient quantity by the animal
- must be supplied in the diet
- quantities vary across species (e.g. more vit C for guinea pigs, NHPs and humans)
- macronutrients
- micronutrients (in parts per million/ppm or mg/kg)
e.g. water, protein, fats/lipids, carbohydrates (CHO), vitamins, minerals
2
Q
non-essential nutrients
A
- can be synthesised by the animal’s body, not a must to be supplied in the diet
3
Q
water (essential nutrient)
A
- most important!!!!
- metabolic reactions & most body processes require or take place in water
- required for transportation of substances throughout the body
4
Q
protein (essential nutrient)
A
- commonly found in muscle, skin, cartilage, organs & blood vessels
- enzymes, haemoglobin & some hormones are made of proteins
- in the event of starvation, proteins will be metabolised to provide the calories that the body needs as a source of energy
5
Q
fats or lipids (essential nutrient)
A
- contains more calories per unit of weight than proteins or carbohydrates
- important in maintaining the structural integrity of cell membranes
- provides thermal insulation (e.g. brown fats in newborns & even some adult animals are metabolised very fast into fatty acids to provide heat for the body)
- stores & transports fat soluble vitamins
- protects the internal organs
6
Q
carbohydrates (CHO, essential nutrient)
A
- main source of energy in body metabolism
- excess is stored as glycogen in the muscle tissue and liver
- when thee storage areas are full, the excess is converted to body fat
7
Q
vitamins (essential nutrient)
A
- organic compounds, only required in SMALL quantities
- 2 types: water soluble & fat soluble
- variation in the quantity of vitamins can cause serious disease
- e.g. deficiency of Vitamin C can cause scurvy
8
Q
water soluble vitamins (essential nutrient)
A
- vitamin C, vitamin B complex (thiamine, riboflavin, niacin, B6, B12, folic acid & biotin)
- easily lost from the body system & must be replenished daily.
- NOTE: as vitamin C degrades easily, lab animals fed with improperly stored/expired feed or feed that has been exposed to high temperatures may be at risk of deficiency
9
Q
fat soluble vitamins (essential nutrient)
A
- vitamin A, D, E, K.
- stored in fat and not excreted from the body easily (may cause hypervitaminosis)
10
Q
minerals (essential nutrient)
A
- organic or inorganic
- at least 21 minerals are needed to sustain a common lab animal species (e.g. calcium, phosphorus, sodium, iron, etc.)
- mineral deficiency or excess could cause serious disease
11
Q
organic minerals (essential nutrient)
A
- beneficial for body metabolism
- formed through biological processes or due to the presence of certain biological material
- has ionic bonds which the body can break down into usable materials for tissue repair & functions
- E.g. kidney stones.
12
Q
inorganic materials (essential nutrient)
A
- never lived
- elements that cannot bring life to our cells
- has covalent bonds which the body is unable to break down
- body treats them as toxins rather than nutrients
- E.g. prescription iron
13
Q
evaluation of feed
A
- to formulate an animal diet, the contents must be analysed and evaluated using a proximate analysis
- not indicative of feed quality
- does not provide information about vitamin contents
- the proximate analysis is only a list of 6 important characteristics of a feed product as determined by chemical techniques
14
Q
moisture (evaluation of feed)
A
- percentage of water determined by comparing the weight loss of a sample before and after complete oven drying
15
Q
crude protein (evaluation of feed)
A
- measured by assaying the amount of nitrogen in a sample
- N value is multiplied by 6.25 to calculate the total protein
16
Q
crude fat (evaluation of feed)
A
- measures the amount of fat and oil in the feed by using ether to extract the fat from the feed
17
Q
fibre (evaluation of feed)
A
- measures the residue of a feed sample that is neither soluble in hot dilute acid nor hot dilute base
18
Q
ash (evaluation of feed)
A
measures the inorganic residue left after burning the feed sample
19
Q
N-free extract (evaluation of feed)
A
- represents the carbohydrate portion of the feed
- measured by subtracting the sum of percentages of the other characteristics from 100%
20
Q
supplements & treats
A
- only given occasionally!
- to contribute to the animal’s daily calorie intake
- when the animals are eating less of their commercially balanced diet
- used sparingly only when necessary and if the experiment parameters permit it
21
Q
standard diet (commercial diets)
A
- fulfils nutrient requirement more than sufficiently (unless improperly stored)
- nutritionally complete; suitable for different life stages
- composition of nutrients in diets may vary (batch-to-batch, by brand, etc.)
- must obtain batch-analysis certificates with results specific to that batch as these differences may affect experimental results.
- choice of standard diet is dependent on:
> the need of the individual strain/species
> animal’s condition (pregnant/lactating/geriatric, etc.)
> research needs of the investigator
22
Q
custom made diet (commercial diets)
A
- formulated according to principal investigator’s specification to meet experimental needs
- contents are adjusted accordingly (e.g. increased/decreased sodium, fibre, fat, protein, etc.)
- can be irradiated or purified & in pellet or liquid forms
- e.g. high/low fat diets, nutritional deficiency diets, salt modification diets, insulin resistance diets, etc.
23
Q
certified diet (commercial diets)
A
- similar to other diets but certified by the manufacturer that there are no contaminants (e.g. pesticides, heavy metals, etc.)
- used for GLP (quality assured) studies e.g. toxicity
24
Q
autoclavable and irradiated diet (commercial diets)
A
- sterilised feed for animals housed in a barrier facility (e.g. germ free or SPF)
- additional nutrients are often added to the feed so that the diet is still balanced even after autoclaving/irradiating
25
purified diet (commercial diets)
- made from purified ingredients (e.g. casein (milk protein), sucrose, corn starch, fat, oil & cellulose
- used in studies of specific nutritional deficiencies and excesses
- can be reproduced in consistent nutritional value from batch to batch (allows researchers to consistently repeat & modify a study, obtaining accurate data each time)
- contains only very low levels of non-nutritive ingredients
- e.g. diet induced obesity diets, low sodium diets, protein free diets, cholesterol free diets, folic acid deficient diets, high carbohydrates diets
26
verified diet (commercial diets)
- absence of a particular nutrient/molecule
- e.g. feed lacking phytoestrogen used in toxicology studies
27
potential contaminants of feed (general concerns with regard to feed)
- pesticides
- pests e.g. insects & mites
- bacteria, bacterial toxins, mycotoxins
- natural plant toxins
- breakdown products of nutrients
- nitrates, nitrosamines
- heavy metals
28
types of feed
- ground feed (meal)
- pelleted feed
- extruded feed
- semi-moist feed
- canned feed
- roughage hay
- aquatic feed/live feed
29
ground feed (meal)
- granulated/powdered
- most common form for poultry & swine
- for rodents with limited mobility/difficulty chewing (e.g. due to malocclusion)
- high dust concentration may cause respiratory issues in some species such as rats
- due to the greater surface area, it may spoil faster
- if left in humid environments, texture change will occur and feed will clump up
30
pelleted feed
- feed is first ground and then moulded into different shapes and sizes
- most common form for rabbits, rodents and ruminants
- hardness can aid rabbit and rodents in wearing down their teeth
- high fat diets are typically not pelleted as they cannot hold their shape well
31
extruded feed
- feed is passed through a tapered mould under high pressure and heat
- most common form for cats, NHPs and dogs
- more palatable for some species
- tends to be softer and less dense than pelleted food
- good for aquatic animals like frogs and fishes (less dense = floats = harder to disintegrate in water, cleaner water, etc.)
- more fat content because of extrusion (puffed up, different from pelleted!)
32
semi-moist feed
- for dogs and cats
- usually high in calories = unsuitable for routine feeding of caged animals
- contributes to dental problems over long term studies
- in mice, it can be used for weaning/post-surgeries
33
canned food
- palatable for dogs and cats
- expensive
- short shelf life after opening
- useful to whet a sick animal's appetite or hide medications
34
supplemented fibre
- hay
- given to ruminants, rabbits & guinea pigs
- timothy/alfalfa hay
- needs to be irradiated/autoclaved
- HAY NOT STRAW (straw has no nutritional value)
35
aquatic feed
- pelleted (more nutritious, contains more protein & fibre which reduces the likelihood of overfeeding)
- flaked (enrichment, feeding at the surface, can contain more fat than pellets, shorter shelf life compared to pellets)
36
live feed
- certain strains can eat this feed: fish, tree shrews, amphibians, reptiles, etc.
- examples of live feed: brine shrimp larvae (artemia), paramecium, rotifers, mealworms, crickets
- to ensure that reptiles and amphibians receive enough calcium, supplements in the form of powder can be sprinkled onto the live prey
37
important aspect of feeding
- unless indicated otherwise by the investigator, easily accessible & palatable feed + drinking water must be provided daily or freely
- pay attention to the transportation, storage & handling of feed to avoid spoilage/contamination with pollutants, disease vectors, parasites or pathogens that may affect the nutritional value
- even if contamination of the food is not great enough to cause poisoning, enzymatic activity/hormone production etc. may still be affected
- if necessary to change diets, do it gradually over a few days and not suddenly so as to not stress the animal (if too sudden, they may not eat or even exhibit diarrhoea)
38
nutrition required for growth and reproduction
- has special nutritional needs
- pregnant rats need 10-30% more energy and will eat 10-20% more food
- this may increase up to 140% more food by day 16-18 of gestation
- if the nutritional needs of pregnant rats are not met, the size & viability of the pups may be decreased and the dam may even end up absorbing them
- diets higher in proteins & calories are recommended for growth and lactation
- MORE NUTRITION!!
- the young of most rodents begin eating feed 10-14 days after birth
- cats and dogs do not begin eating solid food until they are 3-4 weeks old
39
nutrition required for lactating dams
- nursing females need a high protein diet to adequately nurse their young
- 2-4 times more energy than non-nursing females
- more babies to feed = more energy consumed!
- during the 2nd week of lactation, dams will lose body fat so it is important to get the MAXIMUM protein and energy required to maintain their health
- poor nutrition = poor milk production = malnutrition of pups
40
effects of overfeeding pregnant dams
- foetuses may grow too large
- dams may have poor muscle condition and fat deposits which interfere with the process of giving birth
- in dogs, early weight gain may increase the risk of dystocia (advisable to do ultrasound by 6-9 weeks to get an estimate of the size of the litter, more puppies = more nutrients, less puppies = less nutrients)
41
signs of dehydration
- VERY SERIOUS
- animal appears restless & distressed within the first 24 hours
- less urine and faecal production
- decrease in dry food consumption
- may be a complication of a disease or caused by faulty watering system
42
signs of decreased food intake
- significant weight loss
- unusually prominent skeletal structure
- sometimes, a dominant animal may be preventing others from getting to the food (may want to remove this animal)
- must be observant to spot the problem quickly
43
factors affecting the choice of diets
- genetics of breeds, strains, stocks & sexes
- stages of life e.g. growth/maintenance/pregnancy/lactation
- different environmental parameters/conditions
- research protocols (restricted quantity or nutrients)
- research conditions (more palatable diet to encourage appetite if the procedures are noxious)
- changes in dietary intake
- change of microbial status in germfree animals or when coprophagy in rodents is prevented
44
treats & why they should not be fed too much.
- treats such as fruits, vegetables, tablets, trail mixes, cereal
- different types of enrichment food are utilised for different species
- treats should not interfere with an animal's intake of its normal diet or protocol requirements!
- THIS IS BECAUSE treats are usually not nutritionally balanced and if they eat treats instead of their diet, they may suffer from nutrient deficiencies and have long-term health effects
- some enrichment tablets that are nutritionally sound can be fed in larger quantities than others (e.g. those based on grain diets/purified diets & acts as a supplement)
45
foraging behaviour (environmental enrichment using food)
- standard feeding practice is to provide food freely via a food hopper = little opportunity for foraging behaviour
- preference testing has shown that rats show inclination for the foraging device
- foraging device shows a tendency to decrease aggression between pairs of rats housed together
- reduces social stress
- reduces risks of aggression-induced injury
- corn-cob bedding can offer a foraging opportunity as well
46
skinner's operant conditioning
- operants: intentional actions that have an effect on the surrounding environment
- 3 types of responses
- neutral operants: responses from the environment that neither increase nor decrease the probability of a behaviour being repeated
- reinforcers: responses from the environment that increase the probability of a behaviour being repeated (can be positive or negative)
- punishers: responses from the environment that decrease the probability of a behaviour being repeated (weakens behaviour)
47
positive VS negative reinforcement
- positive = strengthens behaviour by providing a reward, e.g. receiving food when pressing a lever
- negative = strengthens behaviour by stopping/removing an unpleasant experience, e.g. removing electrical shocks when pressing a lever
48
types of bedding materials
- shredded paper
- recycled cellulose fibre (absorbent, less dusty)
- mixture (enrichment) of alpha cellulose (absorbent) & corn cob (ammonia control)
- pelleted paper chips made from recycled newspaper (dust-free, absorbent, ammonia control, often used for diabetic animals)
- soft pellets & curly flakes (unique blend of unprinted newspaper)
49
what does choice of bedding depend on?
- type of housing
- species of animal
- experimental requirements
- practicability
50
what is an appropriate quantity of bedding?
- enough to keep animals comfortable and dry at all times
51
direct bedding
- touching/in contact with animals (e.g. corn cob in rodent cages, hay strewn on stable floors)
- corn cobs: ammonia control, allows rodents to gnaw for enrichment. must be complemented with nesting materials. the abrasive nature may cause foot lesions in immunocompromised mice.
- paper chips: absorbent but not as cost effective as corn cobs.
52
indirect bedding
- bedding that is placed underneath cages
- e.g. rabbits & NHPs have catch trays lined with absorbent materials
- cellulose material: can add antibiotics to stop bacterial growth
- wood shavings: increases foraging time, retains heat, absorbent, but will clog up drains & requires the additional step of sweeping before washing the housing (husbandry considerations)
53
purpose of bedding
- thermal regulation (especially for hairless strains e.g. nude mice)
- absorbs moisture, faecal & urinary waste (limits the animal's contact with excreta)
- environmental enrichment (nest construction, gnawing, etc.)
- minimises growth of microorganisms by lowering the amount of ammonia in the rodent cages
54
important criterions for the selection of bedding
- dust (saw dust, wood shavings/chips, etc. may irritate the respiratory tract)
- toxicity (untreated recycled newspaper materials may contain carbon/dyes due to the printed letters & pictures)
- sanitation (is it autoclavable & sterile?)
- absorbency (absorbing urine & minimising odours)
- non-nutritive (must have low nutritional value as lab animals like to gnaw)
- ammonia control (may be dependent on the frequency of cage change. higher change frequency = not as important)
- cost effectiveness
- long-lasting (saves cost & labour needed to change)
- easy cleanup (easy and safe to clean)
- static electricity (may clog dispensing equipment)
- comfort (no sharp edges that may be painful)
55
how often should bedding be changed?
- no set rule, depends on various factors
- could vary from daily to weekly
- try not to change too frequently due to the pheromones & behaviour of the animals (unless research objectives state otherwise)
- minimum once a fortnight (2 weeks) in SPF facilities
- if the cage is wet, change it immediately!
56
what are the factors that affect the frequency of bedding changes?
- number & body size of the animals in the cage (more/bigger animals = more waste)
- size of the cage (small cage = less bedding to dilute the waste out = gets dirty faster)
- urinary & faecal output amount (diabetic animals/animals undergoing metabolism tests may produce more waste)
- appearance & wetness of bedding (wet = reached maximum capacity = must be changed. OR materials that have poorer absorbency must be changed more frequently)
- experimental conditions (animals with surgical wounds require very clean environment = more frequent changes)
57
concerns regarding material type
- nude mice do not have eyelashes. paper bedding/bedding with a lot of dust should be avoided as it could lead to periorbital abscesses (irritates their eyes)
- nude mice may get conjunctivitis from cotton nestlets
- bedding can influence mucosal immunity & endocytosis
- untreated softwood beddings can impact metabolism (aromatic wood shavings e.g. pine/cedar should be avoided as they may induce the activation of hepatic microsomal enzymes & affect experimental results)
- avoid cotton/shredded paper in breeding cages as pups may become entangled in the fibres, causing suffocation or loss of limbs
- BEST BEDDING FOR NUDE MICE = CELLULOSE!
58
things to take note for storage of bedding materials & feed
- always keep them dry! moisture = fungal growth (e.g. Aspergillus)
- store on pallets/racks/carts, elevated from the ground to minimise contamination & preserve quality
- follow the storage methods used by manufacturers and/or suppliers
- during autoclaving, bedding may absorb moisture & lose absorbency thus supporting the growth of microorganisms. appropriate DRYING TIME and storage conditions should be used
59
good practices for storage of bedding materials & feed
- adequate storage space so that supplies do not hinder husbandry
- separate area for storage that is free of pests & protected from contamination/toxic/hazardous substances
- make sure feed is NOT subjected to any increase in temperature/humidity for prolonged periods
- storage bags must be at least 6 INCHES away from the walls (facilitates cleaning & prevents contamination from condensation/mould)
- live feed should be stored in appropriate containers to preserve nutritional content, minimise contaminants & prevent entry of pests
- fruits & vegetables in fridges to avoid spoilage
- unopened cans can be stored as indicated on the can
- pest management program with regular inspections
- no cracks or crevices on the walls (for easy disinfection)
- pipelines, drains and air filters should be well sealed & inspected frequently
- maintain good housekeeping & cleanliness
- follow manufacturer's recommendations for storage!
60
how to curb increases in temperature + what are the effects? (storage of bedding materials & feed)
- control the environment with cool climate control (temperature below 21 degrees celsius & humidity less than 50%)
- increased temperature induces rancidity, high humidity
- fungal and mould growth
