FELASA Module 6 Nutrition

FELASA Module 6: Nutrition
 Most animals can be fed a complete diet in the form of pellets
 These pellets can have its components divided into fractions of macronutrients
 Carbohydrates come in a digestible form and non-digestible forms known as fiber
 Some fibers may be digestible under some circumstances (e.g. if an animal has
different gut bacteria)
 If we burn the pill all the macronutrients will burn but the minerals will remain as ashes
 These minerals are essential for the animal
 Essential nutrients
 In the fat fraction there should be the essential fatty acids linoleic, linolenic and
arachidonic acid
 These should compromise around 1-1.5% of the metabolizable energy
 The protein fraction must contain arginine, histidine, isoleucine, leucine, lycine,
methionine, phenylalanine, threonine, tryptophan and valine
 Macrominerals should be supplied with more than 100mg per day
 Thid includes calcium, phosphorus, magnesium, sodium, potassium, chloride and
sulfur
 Microminerals can be supplied with less than 100mg per day
 These include iron, cobalt, chromium, copper, iodine, manganese, selenium, zinc
and molybdenum
 Vitamins are organic molecules which essential but are not covered by the terms
essential fatty or amino acids or minerals
 Vitamins A, D, E and K are fat soluble and there is a minimum daily need
 B vitamins are water soluble and some daily needs can be defined
 Vitamin C is essential and only considered a vitamin in guinea pugs and primates,
whereas other animals can synthesise it themselves
 Energy
 When burning a food pellet a certain amount of gross energy is released
 When an animal eats the food pellet only some of it is digestible energy
 The rest will pass through the gut and leave the animal as feces
 Some of the digestible energy that enters the systemic parts of the animal is secreted
as urine
 Out of the food pellet eaten only a fraction is metabolizable energy
 Catabolism- breakdown of complex molecules into smaller ones
 Releases energy
 Anabolism- building larger molecules out of smaller molecules or atoms
 Uses energy
 Just because an animal has a certain intake of metabolizable energy it might not be
able to use it all for catabolism, and therefore create energy
 If fed freely the animal will eat to fulfill its need for energy
 This won’t always be valid
 Precise energy needs are difficult to define
 Growing animals need more energy and more protein than adult animals
 Pregnant or lactating need energy for producing foetuses and milk
 Therefore animals in these conditions have different food intakes and their diets
should be adapted
 The gastrointestinal tract consists of the stomach, the small intestine and the large
intestine
 Broken into smaller bits it also includes the esophagus, stomach, duodenum, jejunum,
ileum, cecum, ascending colon, descending colon and rectum
 Animal species differ in relation to how much of their gastrointestinal tract is large or
small intestine
 Cats and dogs have more small intestine than humans
 Pigs, rats, mice and rabbits have more large intestine than humans
 The high fraction of small intestine in cats makes them carnivores

,  Humans are omnivores with them needing proteins and slow digestible
carbohydrates
 Rabbits are herbivores and need lots of slow digestible carbohydrates and fibers
 Dogs, pigs, rats and mice are omnivores due to them living close to humans for
many generations
 Their gut anatomy has adapted to reflect this
 There is a wide range within species of what diet components are needed
 If mice and rats are given high protein diets they will grow quickly but develop
tumours
 Guinea pigs have a need for vitamin C but other species don’t
 At least 15% of the diet needs to be fiber for rabbits
 Because animals are usually fed from pellets from big suppliers you don’t have to worry
too much about what to feed them
 If manipulating diet in a study you need to know what you can and can’t do
 Some nutrients can be overrepresented in the diet without complications
 Others should be closely dosed
 Nutrient Requirement of Laboratory Animals from the US National Research Council tells
you the requirements
 Diets for laboratory animals are produced by commercial laboratory animal diet producers
 You can purchase a complete diet fulfilling all nutrient requirements
 Some companies offer standard diets based on natural ingredients and special7purified
diets based on synthetic ingredients
 Some companies work with a closed formula which tells you the level of nutrients but
not the components
 Others work with an open formula which tells you which ingredients are used
 In most cases of animal nutrition diets in the catalogues of commercial diet producers
are used
 This is the case for studies where the diet is not an experimental factor
 Also used within large research areas like diabetes, obesity, osteoporosis an vitamin
research
 Purpose made diets can be ordered for some research diets
 Normally at least 10kg of pills will need to be ordered as it is difficult to make a
uniform diet in small amounts
 Purpose made diets are usually based off of the standard diets
 Natural Ingredient diets
 Also known as chow
 Made of:
 Whole grains (corn, barley and wheat)
 Mill by-products (bran)
 High protein meals (like soybean fish and casein)
 and mineral sources (like bone meal)
 Advantages:
 Cheap
 Animals like it
 Nutritious
 Disadvantages:
 Variation between batches from the same producer
 Even higher variation between producers
 Can’t remove a single substance without removing major fractions of the diet
 Contains uncontrolled biologically active compounds
 Contamination risk for pathogens like Salmonella
 Can be differences in natural ingredients across the world
 In Europe wheat and barley are used in North America wheat and corn are used
 Wheat and barley contain gluten which corn does not