ANIMAL NUTRITION (24/1/2013) (In order of slides on handout)
AIMS of course:
- differences + similarities in nutrient reqs between man/animal
- Nutritional/other factors affecting animal production
- Improving the quality of human diets though animal production (can manipulate and design
diets for a specific outcome)
OBJECTIVES of animal nutrition:
- Promote well- being, good health, welfare and production efficiency in farm animals- in
environmentally friendly and sustainable ways
- Produce high quality and nutritious products to improve quality of human diets
Differences in aims between animals/humans:
- Humans eat to aim for longevity- animal don’t (not necessarily the objective
- Humans have dietary choice- animals don’t (eat to meet set goals for objectives)
- Animals have environmental concerns linked- (set limits of co2 and o2)
- Animals eat for production e.g. of meat, milk, eggs
Aims of animal nutrition:- fed in order to produce quality, desirable food for man and help provide a
balanced diet. Animal diet makes use of food unacceptable to man such as co/by products. Animals
also produce useful by products such as wool and leather (from skin). There is some competition
between man and animal for resources- must ensure good health for both. Animal nutrition
necessitates systems of well-being and best welfare although, it has limits on environmental impact
e.g. of greenhouse gases. The nutrition is based on market demands- farmers are told what they
need to produce and schemes are introduced to ensure best production. Economically viable
systems are introduced for best income for producer- at the moment only earn 25% of cost. Also
work to maintain countryside as we know it e.g. through animals grazing. Operate simple and
flexible systems e.g. input-output relationship.
(see hand out for diagram)
Digestion
Can be mechanical- mastication and muscular contraction of alimentary canal. (mouth- grind
ingredients)
Can be Chemical- enzymatic hydrolysis in various digestive juices- (plant enzymes in unprocessed
food may also play a small role)
Can be Microbial- in rumen and large intestine- also enzymic; brought about by bacteria, protozoa,
fungi. In monogastric animals microbial digestion occurs mainly in LI. (although low level in pigs and
birds)
, MONOGASTRIC ANIMALS- e.g. pigs- same as humans and therefore used as a model in
understanding digestion (see handout for diagram)
DIGESTIVE TRACT= tube extending from mouth to anus lined with mucous membrane. FUNCTION=
prehension, ingestion, communition, digestion and absorption of food and elimination of solid waste
PARTS= mouth, pharynx, oesophagus, stomach, SI, LI
LARGE INTESTINE
- Main site of absorption is SI and most hydrolysed nutrients have been absorbed by LI. Some
nutrients are resistant to enzyme action in alimentary canal (gut of animals).
- Extensive microbial activity occurs here- espec caecum
- Slow rate of passage (residence time= 20-40h) and abundant nutrient sources encourage
prolific bacteria growth (10^9-10^11 bac/gram contents)
- Many species- not all diet related- aerobic and anaerobic e.g. lactobilli, streptococci,
clostridia, yeasts etc. These METABOLISE wide range of carb/nitrogen sources from dietary
and endogenous residues
- This produces many products; indole, skatole, phenol, amines, ammonia, VFA-
(predominates>)ACETIC, PROPIONIC + BUTYRIC
- VFAs are absorbed and contribute to energy supply of pig
- Microbial fermentation accounts for 8-16% of organic matter disappearing from GI tract
- No amino acid absorption- all used up + V little cellulose/polysaccharide absorption
- Faces= 60-80% bacteria + <2% protein undigested, diet origin
- Bacterial action in LI may be beneficial – synthesis of some B vits- although vitamindietary
source also needed
DIGESTION IN A FOWL
PARTS= beak (no teeth), oesophagus, crop (food reservoir), Proventiculus (glandular stomach),
Gizzard (may have grit, proteolysis occurs here), duodenum jejunum, ileum, caecum- rectum, Cloaca
(combines function of rectum and bladder- faces and urine excreted together)
Taste is limited to back half of tongue and adjacent pharynx
Crop is a diverticulum of oesophagus- 2/3 down length- filled and emptied by peristalsis
Proventriculus- produces HCl and pepsinogen. Food passes through due to oesophageal
contractions
Gizzard grinds the food to a smooth paste. Presence of grit increases breakdown of whole
grains by 10%
Duodenum- encloses pancreas, 3 pancreatic and 2 bile ducts open into intestine at
termination of duodenum
Pancreatic juice- same as mammalian and same breakdown of macronutrients
Caeca empties by peristaltic contractions and combined excretion= simpler to use as a
screening material to test digestibility of new foods
Very short colon that transports digesta to its termination @ cloaca
AIMS of course:
- differences + similarities in nutrient reqs between man/animal
- Nutritional/other factors affecting animal production
- Improving the quality of human diets though animal production (can manipulate and design
diets for a specific outcome)
OBJECTIVES of animal nutrition:
- Promote well- being, good health, welfare and production efficiency in farm animals- in
environmentally friendly and sustainable ways
- Produce high quality and nutritious products to improve quality of human diets
Differences in aims between animals/humans:
- Humans eat to aim for longevity- animal don’t (not necessarily the objective
- Humans have dietary choice- animals don’t (eat to meet set goals for objectives)
- Animals have environmental concerns linked- (set limits of co2 and o2)
- Animals eat for production e.g. of meat, milk, eggs
Aims of animal nutrition:- fed in order to produce quality, desirable food for man and help provide a
balanced diet. Animal diet makes use of food unacceptable to man such as co/by products. Animals
also produce useful by products such as wool and leather (from skin). There is some competition
between man and animal for resources- must ensure good health for both. Animal nutrition
necessitates systems of well-being and best welfare although, it has limits on environmental impact
e.g. of greenhouse gases. The nutrition is based on market demands- farmers are told what they
need to produce and schemes are introduced to ensure best production. Economically viable
systems are introduced for best income for producer- at the moment only earn 25% of cost. Also
work to maintain countryside as we know it e.g. through animals grazing. Operate simple and
flexible systems e.g. input-output relationship.
(see hand out for diagram)
Digestion
Can be mechanical- mastication and muscular contraction of alimentary canal. (mouth- grind
ingredients)
Can be Chemical- enzymatic hydrolysis in various digestive juices- (plant enzymes in unprocessed
food may also play a small role)
Can be Microbial- in rumen and large intestine- also enzymic; brought about by bacteria, protozoa,
fungi. In monogastric animals microbial digestion occurs mainly in LI. (although low level in pigs and
birds)
, MONOGASTRIC ANIMALS- e.g. pigs- same as humans and therefore used as a model in
understanding digestion (see handout for diagram)
DIGESTIVE TRACT= tube extending from mouth to anus lined with mucous membrane. FUNCTION=
prehension, ingestion, communition, digestion and absorption of food and elimination of solid waste
PARTS= mouth, pharynx, oesophagus, stomach, SI, LI
LARGE INTESTINE
- Main site of absorption is SI and most hydrolysed nutrients have been absorbed by LI. Some
nutrients are resistant to enzyme action in alimentary canal (gut of animals).
- Extensive microbial activity occurs here- espec caecum
- Slow rate of passage (residence time= 20-40h) and abundant nutrient sources encourage
prolific bacteria growth (10^9-10^11 bac/gram contents)
- Many species- not all diet related- aerobic and anaerobic e.g. lactobilli, streptococci,
clostridia, yeasts etc. These METABOLISE wide range of carb/nitrogen sources from dietary
and endogenous residues
- This produces many products; indole, skatole, phenol, amines, ammonia, VFA-
(predominates>)ACETIC, PROPIONIC + BUTYRIC
- VFAs are absorbed and contribute to energy supply of pig
- Microbial fermentation accounts for 8-16% of organic matter disappearing from GI tract
- No amino acid absorption- all used up + V little cellulose/polysaccharide absorption
- Faces= 60-80% bacteria + <2% protein undigested, diet origin
- Bacterial action in LI may be beneficial – synthesis of some B vits- although vitamindietary
source also needed
DIGESTION IN A FOWL
PARTS= beak (no teeth), oesophagus, crop (food reservoir), Proventiculus (glandular stomach),
Gizzard (may have grit, proteolysis occurs here), duodenum jejunum, ileum, caecum- rectum, Cloaca
(combines function of rectum and bladder- faces and urine excreted together)
Taste is limited to back half of tongue and adjacent pharynx
Crop is a diverticulum of oesophagus- 2/3 down length- filled and emptied by peristalsis
Proventriculus- produces HCl and pepsinogen. Food passes through due to oesophageal
contractions
Gizzard grinds the food to a smooth paste. Presence of grit increases breakdown of whole
grains by 10%
Duodenum- encloses pancreas, 3 pancreatic and 2 bile ducts open into intestine at
termination of duodenum
Pancreatic juice- same as mammalian and same breakdown of macronutrients
Caeca empties by peristaltic contractions and combined excretion= simpler to use as a
screening material to test digestibility of new foods
Very short colon that transports digesta to its termination @ cloaca
