Animal Nutrition I Flashcards
3 needs to satisfy an adequate diet of an animal
Fuel
Organic raw materials for biosynthesis
Essential nutrients
Activities than an animal needs nutrients for
Maintenance
Foetal growth
Movement
Milk/wool production
Growth
6 nutrients required by an animal
Amino acids
Energy
Fatty acids
Vitamins
Minerals
Water
Maintenance (def.)
The energy needed for vital functions, regardless of production
Difference between food and nutrients
Food - the edible material (grass, hay)
Nutrients - specific components of food that are digestible, which can be utilised
How are CHO and protein digested in a ruminant?
Microbial fermentation
What are CHO and protein broken down into?
CHO = VFA
Protein = microbial protein
Overall function of the GI tract
Prehension
Ingestion
Digestion
Absorption of food
Elimination of solid waste material
pH of pig saliva
7.3
Coprophagy (def.)
Animals that ingest faeces
3 salivary glands in the mouth and where they’re located
Parasitoids - in front of each ear
Submandibular - on each lower jaw
Sublingual - under the tongue
Saliva composition
99% water
1% inorganic salts
Mucin
Alpha amylase
Complex lysozymes
What animals do not have salivary amylase?
Horse, dog, cat
What does alpha amylase in pigs hydrolyse?
The alpha (1-4) glucan links that are found in polysaccharides which contain 3+ alpha (1-4) D glucose units
Functions of the stomach
Produce pepsinogen
Secrete HCl
Acts as a barrier to harmful microorganisms
What region in the stomach produces mucus?
The cardiac region, fundic region, and pyloric region
Capacity of an adult pig stomach
8L
What is the endocrine function of the pancreas?
Produce insulin
Where is the site of main nutrient absorption?
Jejunum
What 4 enzymes are secreted by the pancreas?
Chymotrypsin
Trypsin
Carboxypeptidase
Pancreatic amylase
What enzyme breaks down lactose?
Lactase (into glucose and galactose)
3 ways villi drain into lymphatic system
An arteriole
A lacteal
Venules
Feeding strategy of goats/sheep
Intermediate feeders
3 sections of the large intestine
Caecum
Colon
Rectum
Longest section of the Large Intestine in the pig
Colon
Forms that CHOs are digested as
Monosaccharides (glucose, fructose, galactose)
Main site of water absorption
Large intestine
3 VFAs produced in a pig’s large intestine
Acetic
Propionic
Butyric
5 specialised organs in poultry animals
Beak
Crop
Proventriculus
Gizzard
Cloaca
What makes the cloaca a specialised organ?
It’s a common chamber and has purpose for digestive, urinary, and reproductive systems
What makes hindgut fermenters different?
Large intestine is more complex and much bigger than monogastrics
How are the glucose beta glucoside links broken down in a hindgut fermenter?
In the large intestine, hydrolysed by cellulase
4 regions in the stomach
Oesophageal
Cardic
Fundic
Pyloric
What fibre is not digestible by pigs?
Beta glucan
Amount of saliva produced by a sheep per day
7L
Chambers of a ruminant stomach
Rumen
Reticulum
Omasum
Abomasum
What stimulates rumination?
The stimulation of the epithelium at the anterior end of the rumen (determined by roughage content)
Amount of saliva a cow produces per day
150L
Function of buffering compounds and mucin
Buffering compounds - maintain rumen pH
Mucin - prevents bloat
Difference between a monogastric and ruminant oesophagus
A ruminant oesophagus has striated muscle along its entire length, a monogastric doesn’t
pH of the rumen
5.5-6.5
How much of a ruminants day is taken up by rumination?
1/3
Are protease enzymes present in the saliva of a ruminant?
No
2 types of m/o present in the rumen and reticulum of a ruminant
Bacteria and protozoa
What is non-protein nitrogen (NPN)?
Components which are not proteins but can be converted to proteins by rumen microbes (eg. urea, ammonia)
When is metabolizable protein digested?
Pre- or post-ruminally
MP is used for milk protein synthesis
Function of soluble protein
A readily available nitrogen source for rumen microbes. It is then degraded in the rumen to ammonia
What are the non-structural carbohydrates composed of?
Starch and sugars
What is the most common measure of structural carbohydrates?
Neutral detergent fibre
What is the difference between the composition of a neutral detergent fibre and an acid detergent fibre?
NDF is composed of cellulose, hemicellulose, and lignin
ADF is composed of cellulose and lignin
When are VFAs produced?
When carbohydrates undergo microbial fermentation
How are amino acids transported to the rumen
Inside microbial cells
The fate of the amino acids inside the microbial cells is determined by the availability of energy. What will happen if energy is available?
AA will be used directly for microbial protein synthesis
What will happen if energy is limiting?
AA will be dominated by microbes releasing ammonia and their C-skeleton. The C-skeleton will then be fermented into VFAs
What type of amino acids are bacteria capable of synthesising?
Both essential and non-essential AA
What happens in the rumen when the ammonia requirement is in excess?
Ammonia is absorbed in the blood and carried to the liver where it is converted to urea
What happens to the urea produced?
The urea may be returned to the rumen via saliva or through the rumen wall. Majority is excreted in the urine (wasted)
Examples of Non-Protein Nitrogen
Urea
Biuret
Ammonia
What enzyme is used to produce urea from ammonia?
Urease
What form of protein provides a greater diversity of amino acids than microbial protein?
Rumen degradable protein
Rumen undegradable protein
Escape rumen degradable protein
What are the two most likely limitations to microbial protein synthesis?
Energy availability
Ammonia availability
What is the biological value of microbial protein?
Approx 80%
Which are more efficient at protein utilisation; monogastrics or ruminants?
Monogastrics can convert 85% of the nitrogen absorbed to tissue protein while ruminants are only 25% efficient in nitrogen use
In ruminants, where does the other 75% nitrogen go?
50% urine
25% excreted in faeces
Is ammonia toxic to cells?
Yes. Excess is immediately absorbed through the rumen wall and transferred to the liver where it is converted to urea.
What are some additives that reduce nitrogen loss?
Ionophores
Essential oils which can contain volatile fractions of plants
Tannins
What are carbohydrates composed of?
Carbon, Hydrogen, Oxygen
What determines how much milk or meat an animal will produce?
The amount of energy consumed
How do plants store glucose?
As amylose or amylopectin
What is the benefit of glucose being stored in polymeric form?
It minimises osmotic effects
What is amylose?
A glucose polymer with α(1->4) linkages
What is a reducing end?
The end of the polysaccharide with an anomeric C1 not involved in a glycosidic bond
What is amylopectin?
A glucose polymer with mainly α(1->4) linkages
What do the branches in amylopectin provide?
Multiple chain ends at which enzymatic cleavage can occur
What is the glucose storage polymer in animals called?
Glycogen
What does the highly branched structure of glycogen permit?
Rapid glucose release from glycogen stores (eg. muscle during exercise)
What is a major constituent of plant cell walls?
Cellulose
What does the pancreas secrete?
Trypsin (cleaves proteins at basic AA)
Chymotrypsin (cleaves proteins at aromatic AA)
Carboxypeptidase (takes of terminal acid group from protein)
Pancreatic amylase (degrades carbohydrates)
Small intestinal enzymes and what they break down..
Sucrase: sucrose-> glucose + fructose
Maltase: maltose -> glucose
Isomaltase: maltose
Lactase: lactose -> glucose + galactose
Intestinal lipase: fatty acids
Which enzyme do monogastrics lack?
Cellulase (to digest the carbohydrate cellulose)
What is the main digestive gland in the body?
Pancreas
Which region of the intestine produces the most VFA’s in pigs?
Colon
Which m/o is the most abundant in the rumen of a mature ruminant?
Bacteria
Which region of the ruminant stomach makes up the largest portion of the calf digestive tract?
Abomasum
What food supplement maximises rumen development?
Concentrates
Which of the VFA’s has the most influence on rumen development?
Butyric acid
What is the main glucose transporter in the small intestine of pigs and poultry?
SGLT1
What molecules is made up of chains of glucose linked by beta (1-4) linkages?
Cellulose
Which enzyme breaks down starch?
Amylase
What is the main region of nutrient absorption in pigs?
Jejunum
