41 Animal Nutrition Flashcards
What factors must a diet satisfy?
Energy needs, building blocks for macromolecules and essential nutrients.
To build macromolecules, what do animals need a source of and where do they get it from?
Nitrogen: amino acids
Carbon: carbohydrates
What are essential nutrients?
Substances that are needed for cellular functions but can not be synthesised by the organism, and thus must be part of the diet.
What is an example of a human essential nutrient that can be produced by some animals?
Vitamin C which is an essential nutrient for humans, guinea pigs, domes birds and snakes by can be synthesised by most other animals.
What are the groups of essential nutrients?
Essential amino acids, essential fatty acids, vitamins and minerals.
Which amino acids are essential?
In humans there are 8 essential amino acids (a ninth is needed by infants: histidine)
How can essential amino acids be sourced?
With animal proteins that include more of the 8 we need.
How special adaption of penguins enables them to store amino acids?
They can extract amino acids from their muscles to be used to build feather proteins after moulting.
What fatty acids are essential?
Those that contain one or more double bond and are thus unsaturated.
For example, humans require linoleic acid to make some membrane phospholipids.
Where are essential fatty acids often sourced?
Seeds, grains and vegetables and thus deficiencies in essential fatty acids are rare in humans.
How do vitamins and minerals?
Minerals are inorganic while vitamins are organic.
Minerals can be structural but can also play a role in regulating cell function like
What are vitamins divided into?
Water-soluble and fat soluble
What are the water soluble vitamins?
B1, B2, B3, (no B4) B5, B6, B7, (no B8), B9, (no B10-11) B12 and Vitamin C
What chemical is Vitamin B1?
thiamine
What chemical is Vitamin B2?
riboflavin
What chemical is Vitamin B3?
niacin
What chemical is Vitamin B5?
pantothenic acid
What chemical is Vitamin B6?
pyridoxine
What chemical is Vitamin B7?
biotin
What chemical is Vitamin B9?
folic acid
What chemical is Vitamin B12?
cobalamin
What chemical is Vitamin C?
ascorbic acid
What is the function of vitamin B1?
Coenzyme used in removing CO2 from organic compounds
What is the function of vitamin B2?
Component of coenzymes FAD and FMN
What is the function of vitamin B3?
Component of coenzymes NAD+and NADP+
What is the function of vitamin B6?
Coenzyme used in amino acid metabolism
What is the function of vitamin B5?
Component of coenzyme A
What is the function of vitamin B7?
Coenzyme in synthesis of fat, glycogen, and amino acids
What is the function of vitamin B9?
Coenzyme in nucleic acid and amino acid metabolism
What is the function of vitamin B12?
Production of nucleic acids and red blood cells
What is the function of vitamin C?
Used in collagen synthesis; antioxidant
What are the symptoms of vitamin B1 deficiency?
Beriberi (tingling, poor coordination, reduced heart function)
What are the symptoms of vitamin B2 deficiency?
Skin lesions, such as cracks at corners of mouth
What are the symptoms of vitamin B3 deficiency?
Skin and gastrointestinal lesions, delusions, confusion
What are the symptoms of vitamin B5 deficiency?
Fatigue, numbness, tingling of hands and feet
What are the symptoms of vitamin B6 deficiency?
Irritability, convulsions, muscular twitching, anemia
What are the symptoms of vitamin B7 deficiency?
Scaly skin inflammation, neuromuscular disorders
What are the symptoms of vitamin B9 deficiency?
Anemia, birth defects
What are the symptoms of vitamin B12 deficiency?
Anemia, numbness, loss of balance
What are the symptoms of vitamin C deficiency?
Scurvy (degeneration of skin and teeth), delayed wound healing
What are the fat soluble vitamins?
A, D, E and K
What chemical is vitamin A?
retinol
What chemical is vitamin D
N/A
What chemical is vitamin E?
tocopherol
What chemical is vitamin K?
phylloquinone
What is the function of vitamin A?
Component of visual pigments; maintenance of epithelial tissues
What is the function of vitamin D?
Aids in absorption and use of calcium and phosphorus
What is the function of vitamin E?
Antioxidant; helps prevent damage to cell membranes
What is the function of vitamin K?
Important in blood clotting
What are the symptoms of vitamin A deficiency?
Blindness, skin disorders, impaired immunity
What are the symptoms of vitamin D deficiency?
Rickets (bone deformities) in children, bone softening in adults
What are the symptoms of vitamin E deficiency?
Nervous system degeneration
What are the symptoms of vitamin K deficiency?
Defective blood clotting
How can minerals be grouped in terms of need?
More than 200 mg per day needed, less than 200 mg, and trace elements
What minerals are needed in quantities greater than 200 mg per day?
Calcium, Phosphorous, Sulfur, Potassium, Chlorine, Sodium, Magnesium
What minerals are needed in quantities less than 200 mg per day?
Iron, Fluorine and Iodine
What is the function of Ca?
Bone and tooth formation, blood clotting, nerve and muscle function
What is the function of P?
Bone and tooth formation, acid-base balance, nucleotide synthesis
What is the function of S?
Component of certain amino acids
What is the function of K?
Acid-base balance, water balance, nerve function
What is the function of Cl?
Acid-base balance, formation of gastric juice, nerve function, osmotic balance
What is the function of Na?
Acid-base balance, water balance, nerve function
What is the function of Mg?
Enzyme cofactor; ATP bioenergetics
What is the function of Fe?
Component of hemoglobin and of electron carriers; enzyme cofactor
What is the function of F?
Maintenance of tooth structure
What is the function of I?
Component of thyroid hormones
What are the symptoms of Ca deficiency?
Impaired growth, loss of bone mass
What are the symptoms of P deficiency?
Weakness, loss of minerals from bone, calcium loss
What are the symptoms of S deficiency?
Impaired growth, fatigue, swelling
What are the symptoms of K deficiency?
Muscular weakness, paralysis, nausea and heart failure
What are the symptoms of Cl deficiency?
Muscle cramps, reduced appetite
What are the symptoms of Na deficiency?
Muscle cramps, reduced appetite
What are the symptoms of Mg deficiency?
Nervous system disturbances
What are the symptoms of Fe deficiency?
Iron-deficiency anemia, weakness, impaired immunity
What are the symptoms of F deficiency?
Higher frequency of tooth decay
What are the symptoms of I deficiency?
Goiter (enlarged thyroid gland)
What minerals are needed in trace amounts?
Chromium (Cr), cobalt (Co), Copper (Cu), manganese (Mn), molybdenum (Mo), selenium (Se), and zinc (Zn).
What behavioural adaptions allow animals to survive in condition of low nutrients?
Many herbivores i.e. deer will lick rocks to gain missing nutrients, especially phosphorus which is lacking in grass
Some carnivores i.e. spiders will switch to prey they no will have a specific nutrient
What happens during undernutrition?
First carbohydrate and fat stores are used, second muscles are broken down to extract energy form the amino acids.
What is hemochromatosis?
A buildup of iron in the blood.
What do folic acid supplements specifically prevent?
Neural tube defects
What are the basic steps of food processing?
Ingestion, digestions, absorption, and elimination
What are the two forms of food processing in terms of the location of actual digestion?
Intracellular digestion and extracellular digestion.
What is intracellular digestion?
When the hydrolysis of food occurs when vacuoles formed by endocytosis fuse with lysosomes.
What are the basic feeding mechanisms of animals?
Suspension Feeders, Filter feeders, Substrate feeders, Fluid feeders and Bulk feeders.
What are suspension feeders?
Animals that eat small organism or food particles suspended in the water. Cilia sweep the food particles into the animals mouth in a film of mucus.
What are filter feeders?
Animals like whales that move water through a filter to obtain food.
How doe filter and suspension feeders differ?
Suspension feeders actively grab food morsels whereas filter feeders scoop them up due to the animals movement.
What are substrate feeders?
Animals like caterpillars that live on or in their food. This also includes many parasites.
What are fluid feeders?
Animals like mosquito that derive their nutrition from consuming fluids.
This includes aphids which drink phloem sap of plants. It also includes non-parasites like hummingbirds and birds which move pollen as they drink nectar
What are bulk feeders?
Animals like pythons that eat large pieces of food (includes vegetables swell as meat)
What animals exclusively perform intracellular digestion.
Sponges
What is extracellular digestion?
Hydrolysis that occurs outside the cell i.e. in compartments (stomach etc.) or by simply secreting enzymes into the environment.
What are organism that secret enzymes then absorb the catabolised products called?
Sacrobionts
What form of digestion is typical of simple animals?
Gastrovascular cavities
What animals have gastrovascular cavities?
Hydras and many flatworms
How is a gastrovascular cavity fundamentally differ from the alternative?
How does a It has only one opening, unlike the alimentary canal.
How does a hydra use its gastrovascular cavity?
It uses its tentacles to stuff captured prey through its mouth into its gastrovascular cavity.
The inside layer of the cavity, named the gastrodermis, has cells that secrete enzymes to break down the prey. Other gastrodermal cells engulf food particles as most macromolecule hydrolysis occurs intracellularly.
Undigested material that remains is then eliminated through the mouth.
What alternative to the gastrovascular cavity is seen in more advanced animals?
An alimentary canal with a mouth and an anus.
What is the advantage of alimentary canals?
Since they are unidirectional they allow food to be a different stages of digestion i.e. ingestion can occur at the same time as absorption.
Describe the digestive system of an earthworm.
A muscular pharynx sucks food in thick is stored and moistened in the crop before passing to the gizzard where small pieces of sand and gravel pulverise it. It then passes to the intestine
Describe the digestive system of an grasshopper.
It has a foregut that consists of an oesophagus as well as a crop to store and moisten it. Most digestion occurs in the Gastric cecae (no intestines) which are pouches that function in absorption and digestion
Describe the digestive system of a bird.
The food is stored in the crop before being pulverised by the gizzard before passing through the intestine to the anus.
How does food move along the alimentary canal?
Peristalsis
How is the rate of food movement controlled?
Sphincters (valves)
What is a undigested food moving down the oesophagus called?
A bolus
What component of saliva enables it to protect the mouth?
Mucus, which is composed of water, salts, cell and slippery glycoproteins called mucins.
Why is mucus important in saliva?
It lubricates the food and protects the mouth from damage.
What directs food not to go down the trachea?
When a person is not swallowing the oesophageal sphincter muscle is contracted, the epiglottis is up so that the glottis is open and air can enter the trachea.
During swallowing the larynx, the upper part of the respiratory tract, moves upward and the epiglottis tips over the glottis, preventing food from entering the trachea.
What is the glottis?
The voice cords and the opening between them.
After it has passed through the stomach, what is the bolus called?
Chyme as it is a mixture of food and gastric juices
What is secreted into the stomach?
Mucus (containing HCO3-), pepsin and HCL
What are substances secreted in the stomach produced by?
Gastric glands which are holes that contain substance secreting cells.
How is mucus released in the stomach?
It is produced by mucous cells, ( part of the gastric glands)
What is the function of mucus in the stomach?
It protects the stomach wall and lubricates the chyme
How is HCl released into the stomach?
By Parietal cells (a form of gastric gland)
How is pepsin released into the stomach?
Chief cells, a form of gastric gland, secrete pepsinogen which is an inactive form of pepsin.
When pepsinogen reaches the interior of the stomach the HCl clips of a region of the pepsinogen to expose its active site.
It is now active and called pepsin
What is the general term from an enzyme which breaks down proteins?
Protease
Why is the pepsinogen –> pepsin process important?
It prevents the pepsin from damaging the chief cells as it is produced.
What causes stomach ulcers?
An acid resistant bacteria named Helicobacter pylori
How long is the duodenum?
Around 25 cm
What is the chain of bile production and secretion.
It is produced in the liver, stored in the gall bladder and secreted into the duodenum
Besides enzymes, what does the pancreas release
An alkaline solution rich in bicarbonate ions to neutralise the stomach acid.
How does bile perform its job?
It contains bile salts which act as emulsifiers (detergents) to increase the surface area of lipids
Besides digestion, what is bile essential in?
The destruction of red blood cells by the liver that are no longer functional. In producing bile, the liver incorporates some pigments that are by-products of red blood cell disassembly. These bile pigments are then eliminated from the body with the feces
What are the stages of fat digestion and absorption? exclude bile
In the intestine lumen triglycerides (fats) are hydrolysed by lipase into fatty acids and glycerol.
After diffusing into the epithelial cell of the intestine the fatty acids and glycerol are recombined into triglyclides. Note that some fatty acids and glycerol do straight to the capillaries.
Triglycerides (and phospholipids, cholesterol and proteins) are incorporated into water soluble globules called ‘chylomicrons’
Chylomicrons leave epithelial cells by exocytosis and enter lacteals, where they are carried away by the lymph and later pass into large veins.
Why is chylomicron formation important?
It ensures that the fatty acids do not clog up the capillaries as they are NOT READILY WATER SOLUBLE, unlike the chylomicron.
Why are bacteria important even in humans?
Some produce vitamins such as Vitamin K, biotin and folic acid
What is an example of a bacterium that lives in humans?
Escherichia coli (E. coli) which is typically harmless.
How does the rectum prevent food from moving into the anus prematurely?
There are two sphincters between the rectum and the anus. The inner one is involuntary and the outer one is voluntary.
How is the urge to defecate stimulated and why does it often follow meals?
The urge to defecate is stimulated by periodical strong contractions of the colon.
The urge to defecate often follows meals as filling of the stomach triggers a reflex that intensifies these contractions.
How do fangs insert venom into prey?
They are sharp so causes a puncture.
Some drip venom in whereas others inserts through the hollow fang like a hypodermic needle.
How does mutualism help digestion?
Many herbivores have gut flora that includes bacteria AND PROTISTS which hydrolyse cellulose.
Can cellulose be digested enzymatically by animals?
Generally not, but a few like termites that eat cellulose-rich wood do have cellulase.
What animals represent different mutualistic adaptions to cellulose digestion?
Hoatzin, horses, rabbits and cattle.
What special mutualistic cellulose digesting adaptations do Hoatzin have?
The hoatzin, an herbivorous bird has a large, muscular crop (an oesophageal pouch) that houses mutualistic microorganisms. Hard ridges in the wall of the crop pulverise leaves as the microorganisms break down cellulose.
What special mutualistic cellulose digesting adaptations do Horses have?
Horses and many other herbivorous mammals house mutualistic microorganisms in a large cecum.
What special mutualistic cellulose digesting adaptations do Rabbits have?
In rabbits and some rodents, mutualistic bacteria live in the large intestine as well as in the cecum. Since most nutrients are absorbed in the small intestine (before the large intestine) much of the digested nutrients are lost as faeces. Rabbits and rodents recover these nutrients by coprophagy (feeding on their faeces) so that the digested nutrients can be absorbed in the small intestine. (Rabbit pellets are only formed on the second attempt)
What special mutualistic cellulose digesting adaptations do Cattle have?
Cattle, as well as deer and sheep, are ruminants with elaborate adaptions.
What are the stages of ruminant digestion? (in order of structures passed through)
1: Rumen
When the cow first chews and swallows a mouthful of grass, boluses enter the rumen.
2: Reticulum
Some boluses also enter the reticulum. In both the rumen and the reticulum, mutualistic prokaryotes and protists (mainly ciliates) digest cellulose. The metabolism of the organism releases fatty acids The cow periodically regurgitates and rechews the cud (partly digested food) to further break it down
3: Omasum
The cow then reswallows the cud, which moves to the omasum, where water is removed.
4: Abomasum
The cud, containing great numbers of microorganisms, finally passes to the abomasum for digestion by the cow‘s own enzymes (black arrows).
With what section of the nervous system are the digestive organs regulated?
The “enteric division”
How is glucose stored and where?
Glycogen which is formed by and stored in the liver
When glycogen reserves are full how is energy stored?
By the formation of fats which are stored in adipose tissue.
What hormones are key in regulating the digestive system?
Gastrin, secretin and Cholecystokinin (CCK)
What is the effect of gastrin?
It increases the production of gastric juice
What is the effect of Cholecystokinin (CCK)?
It stimulates the release of digestive enzymes from the pancreas and the release of bile stored in the gall bladder
What is the effect of secretin?
It stimulates the pancreas to release Bicarbonate ions (HCO3-) to neutralise the acidity of the chyme.
What regulates the release of CCK?
The duodenum responds to amino acids or fatty acids in the chyme by releasing CCK.
What regulates the release of Secretin?
The duodenum responds to amino acids or fatty acids in the chyme by releasing secretin.
What regulates the release of gastrin?
As food arrives at the stomach, it stretches the stomach walls and triggers the release of gastrin into the bloodstream which circulates back to the stomach and stimulate gastric juice production.
In what way to two hormones combine to regulate the digestive system?
High levels of secretin and CCK indicate that the stomach is full of rich fats. Therefore they inhibit peristalsis and secretion of gastric juices to slow down digestion and give the duodenum more time to digest the fats.
What is a typical blood glucose level?
70-110 mg go glucose per 100 mL
How is blood glucose regulated?
When blood sugar is too high the pancreas releases insulin which stimulates liver and muscle cells to store store as glycogen
When blood sugar is too low the pancreas releases Glucagon which stimulates the breakdown of glycogen into sugars that re released into the blood.
Where is insulin released from?
The pancreas.
Where is glucagon released from?
The pancreas.
What hormones are involved notably in the regulation of appetite?
Ghrelin, Insulin, Leptin, PYY
Where is ghrelin released from and under what circumstances?
Ghrelin is released by the stomach wall as normal mealtime approaches
Where is insulin released from and under what circumstances?
The rise in blood sugar after a meal triggers the pancreas to secrete insulin.
Where is PYY released from and under what circumstances?
The small intestine after meals
Where is leptin released from and under what circumstances?
It is produced by adipose tissue at a constant rate. Therefore as the fat reserves decrease less leptin is released, indicating more food should be consumed.
What is the effect of each appetite regulating hormone?
Ghrelin: increase appetite
Insulin: decrease appetite
Leptin: decrease appetite
PYY: decreases appetite
Where do hunger hormones act?
In the “satiety centre” of the brain which combines these signals to determine appetite.
How can obesity be evolutionarily advantageous?
It promotes the storage of energy in the form of fat and thus long term resilience i.e. to drought, famine and winter
What is an example of an organism that uses obesity as an adaptation?
Petrel chicks are typically obese. This allows energy storage but is also a consequence of the fact that the lipid rich food they eat has little protein so they must consume large quantities of this food to get the protein they need.
