22: Rabbits and Rodents Flashcards
Importance of understanding nutrition in these species?
- niche market for pet food
- lab animal nutrition
- food animals in some countries
Orders, families of rabbits and mouse, rat, hamster
Rabbit = lagomorpha, leporidae
Mouse/rat = rodentia, muridae
Hamster = rodentia, cricetidae
Main difference between lagomorpha and rodentia orders?
Digestive tract and teeth
How are lagomorph teeth different?
Have 4 (2 pairs) incisors in upper jaw (not 2 like rodentia)
Lago are wholly herbivorous, while many rodents can eat meat and vegetation
What type of digestive physiology do lagomorphs have? Diet?
Nonruminant herbivores
Monogastric species but still primarily a forage diet (high fiber) = causes a problem (how to get essential aa) w a unique solution
What organ is unique in lagomorphs? How?
Cecum
Circular-structure
Specialized nervous physiology (tied to circadian rhythm)
Cellulytic bacteria
How is the cecum tied to circadian rhythm?
Cecum can operate at two different speeds
At night, flow of digesta slows down = microbes have more time to work on undigested forage = more microbial protein
Produces diff feces (cecotropes) that are high in microbial protein which rabbits consume
Circadian rhythm in lagomorphs during day vs night
Day = regular activity of GI tract, normal small fecal pellets
During night = tract motility reduced, bacteria in cecum and colon produce cecotropes (high in N/protein, low in fiber) which are consumed so rabbits can capture more N
What are cecotropes high in? How do they allow rabbits to live on low protein food?
Protein, minerals and vitamins
Slide 12
They are high in microbial protein and rabbits have access to recycled N through coprophagy
Consequences if coprophagy is prevented?
Reduced growth rate, lean body mass
Deficiency of amino acids
Suckling and growth in rabbits
Suckle few times a day. At weaning, provide small amount of high Q forage
During growth, forage (fiber) is primary source of nutrients
Diet of an adult rabbit
High fiber, low enegry
Nutrition of rabbits in old age? What is a common issue in old age and why?
High fiber, low E diet cannot be supplied bc changes in teeth and reduced saliva flow
Digesta passage is slower
Gastric stasis (hair balls) are common
Reduced fiber intake/saliva production slows movement and hair balls will form
Slide 16, 17
Life cycle nutrition in rabbits
Optimum fiber intake
What should be added to a rabbits ration during lactation?
Higher crude protein in the form of soybean meal
Molasses (sugar)
Fat (provides more energy)
Slide 18
Origin of the term rodent? Are they coprophagic?
To gnaw
Yes, feces rich in protein and B vitamins (only some produce cecotropes tho)
Slide 20
GI physiology
What are rodents named after?
Specific eating behaviour: hold food w forepaws, lower incisor teeth move back and forth against immobile upper incisors
What are rats and mice typically fed?
‘Rat chow’ and ‘mouse chow’
Occasional special treat (vegetable or cooked meat)
Protein requirement of rats and mice
Low (4-6% for maintenance, 13% growth, 18% repro)
Slide 23
AIN 93 diet
Overfeeding protein in rats and mice. Feeding them during lactation? Problem with group housing?
Not a concern for kidney function
During lactation, increase feed intake dramatically (4 to 5x maintenance)
Occasional cannibalism
Why might irradiation be better than autoclaving for processing?
Irradiation = no heat (little chance of protein damage)
Autoclaving = heating with steam (protein damage)
Guinea pig order? What do they eat? GI physiology? Coprophagy? Protein?
Rodentia
Herbivores
Enlarged cecum (semicircular) and colon
Coprophagy more important in guinea pigs than general rodents (they produce cecotrophs) bc require 18% protein
Natural diet of guinea pigs
Green vegetation and fruit
Old food contained too little fiber and too much E (poor cecotroph formation)
Multiple small meals a day>
Unique metabolism in guinea pigs
Require vitamin C in diet (cannot make ascorbic acid)
Connective tissue synthesis
GI tract of hamsters? Protein requirement?
Stomach separated into cardiac and caudal regions
- first region acts similar to rumen
Require 15% protein
- need some legumes or oilseeds
What should be supplemented in a hamsters diet?
Dark green and yellow vegetables
Nutritional peculiarities in hamsters
Do not require vitamin D w proper Ca:P ratio (make it from cholesterol and sunlight)
Cholesterol metabolism:
- develop atherosclerosis quite easily (used to study heart disease)
- sensitive to dietary cholesterol
