Applied Poultry Nutrition


BVSc Animal Management 2 (Nutrition) Flashcards on Applied Poultry Nutrition, created by Florence Edwards on 14/10/2016.
Florence Edwards
Flashcards by Florence Edwards, updated more than 1 year ago
Florence Edwards
Created by Florence Edwards almost 8 years ago

Resource summary

Question Answer
What are the 2 behavioural requirements of nutrition? Dietary deficiencies associated with abnormal behaviours such as injurious pecking Foraging is an important behavioural need so disruption can cause behavioural problems
Give 2 consequences of insufficient water intake Reduced growth and performance Increased mortality
What is water supply used for, aside from preventing dehydration? Administration of medication and vaccines to treat whole flock simultaneously
Why can high energy density in poultry feed be problematic? Adjust feed intake to energy density of feed Therefore, intake decreases leading to reduced intake of other nutrients
What is meant by nutrient density? Concentration of nutrients in a feed in relation to energy
How can the energy density of a feed be reduced? Increased dietary fibre
What is the consequence of low levels of dietary fibre and protein? Injurious pecking
What is the importance of water in waterfowl? Dip heads to clean eyes and waterproof feathers
What is the technical term for dietary fibre? Non-starch polysaccharides
What is the main energy source for poultry feed in the UK? Wheat and barley
Are poultry able to digest non-starch polysaccharides? No - lack enzymes
What are the 2 forms of non-starch polysaccharide? Water soluble Insoluble
What is a disadvantage of water soluble non-starch polysaccharides? Increased digesta viscosity = increased rate of movement through gut = reduced nutrient absorption and loose faeces
What is a disadvantage of insoluble non-starch polysaccharides? Entrap nutrients
Which type of non-starch polysaccharide is most associated with positive effects? Insoluble
Give an example of an enzyme supplement that can be added to poultry food to aid digestion of non-starch polysaccharides Avzyme 1502 (Danisco) Contains amylase, protease and xylanase (which breaks down hemicellulose)
What is the function of beta-glucanases and xylanases? Break down plant cell walls
What is the amount of enzyme supplement mixed with feed? 50-1000 g per tonne of feed
Give 4 advantages of enzyme supplementation to aid digestion of non-starch polysaccharides Increased energy available from diet Decreased viscosity of digesta so nutrient absorption is improved Better feed conversion so less food can be given Reduces waste as more dietary components can be digested
What is the function of the gizzard? Grinding organ for mechanical digestion of nuts and seeds
Why should poultry be provided with grit? Aids mechanical function of the gizzard
Give 4 advantages of a properly functioning gizzard Improved satiety Increased gut transition time Gut pH (HCl secretion improved) Disruption of oocysts e.g. Coccidia
What is the effect of insoluble fibre on the relative weights of the digestive tract components? Decreased small intestine and proventriculus weight Increased gizzard weight This is indicative of improved GI tract function
What happens to insoluble fibre in the gizzard? Accumulates in gizzard and slows rate of feed passage Increased time for nutrient absorption and increased period of satiety
Give 4 advantages of improved gizzard weight Increased secretion of HCl Increased secretion of digestive enzymes Amylase production in pancreas improved Bile acid contents in jejunum increased = improved fat digestibility
What is an advantage of fat as an energy source? Yields higher levels of metabolisable energy so cheaper than grain
Give 4 sources of dietary fat Soya oil Soya acid oil Recycled vegetable oil Poor fat blend
Which birds are given oils/fatty acids in their diet? Broiler chick starter diets to improve performance Laying hens to improve egg weights (but increased proportion of yolk compared to albumen)
Name the 4 fat soluble vitamins A D E K
What is the function of vitamin A? Bone metabolism
What is the function of vitamin D? Calcium absorption
What is the commercial significance of vitamin E? Meat quality
Give 2 functions of vitamin K Blood clotting Protection against coccidiosis
What component of poultry diets means they usually contain sufficient amounts of essential fatty acids? Usually contain soya oil High in linoleic acid
Name 2 essential fatty acids in poultry Linoleic and linolenic acid (omega 3 and omega 6 fatty acids)
Give 5 possible consequences of linoleic acid deficiency Zero hatchability Low fertility Poor egg production Small egg size Respiratory infections
Name a source of omega 6 Soya
Name a source of omega 3 Flax seed
What is problematic about the ratio of omega 3: omega 6 fatty acids in laying hens? In natural diet high proportion of omega 3 due to green leaf consumption In commercial diet high proportion of omega 6 due to grain content
What is an advantage of supplementing diets with omega 3 in laying hens? Reduced keel bone breakage in laying hens (major problem in loose housing)
What are the 2 nutrients required for feather growth? Methionine and cysteine
What are the 4 nutrients required for egg production? Calcium Phosphorous Trace elements Egg proteins
Give 2 pigments present in egg yolk A carotenoid Canthaxanthin
Give 3 nutrients required for bone health in laying hens Omega 3 Omega 6 Calcium
Give the 9 essential amino acids Methionine Lysine Threonine Tryptophan Isoleucine Leucine Valine Phenylalanine Arginine
Give 3 amino acids synthesised by other amino acids Tyrosine Cysteine Hydroxylysine
What is a disadvantage of synthetic amino acids? Not 100% digestible
What are pullets? Laying hens still growing (before point of lay)
What happens to protein requirements in pullets? Decrease with age until point of lay, when they increase then begin to decrease again
What are protein requirements in pullets? 14-18%
What are protein requirements in layers? 15-18g per day
What are protein requirements in broilers? 18-23%
What are protein requirements in turkeys? 16-28%
What are protein requirements in ducks? 16-22%
What are protein requirements in geese? 15-20%
Give a symptom of arginine deficiency in chickens Feather abnormalities
Give a symptom of lysine deficiency in turkeys Loss of pigment in wing feathers
Give a symptom of protein deficiency (specifically methionine and cysteine) in laying hens Injurious pecking
What is meant by essential amino acids? Deficiency will be limiting to performance, regardless of levels of other amino acids
Give 2 problems associated with amino acid excess Catabolism (oxidation to produce energy) which is a waste of an expensive part of the diet Poor performance
What is meant by ideal protein? Matches supply of each essential amino acid to requirement
What is meant by 'stepped down' feeding? Periods of over/under feeding as diet is changed to match requirements at different ages
What happens to protein requirement with age? Decreases
Can animal protein be fed to poultry in the UK e.g. worms? No - illegal
Give 4 functions of calcium in the body Important constituent of bone and eggs Cells and tissue fluid composition Activity of enzymes in the nervous system Activity of enzymes involved in muscle contraction
Give 3 consequences of calcium deficiency Weak bones Low egg production Soft or broken shells
What is a consequence of calcium excess? Reduced egg numbers
Why is calcium extremely important in laying hens? Sequestered from bone to produce egg shells If not replaced will result in poor egg shell quality Also causes bone weakness and osteoarthritis predisposing to fractures and keel damage
Which 2 nutrients does calcium need to be balanced with? Phosphorous Vitamin D
Which condition can calcium, phosphorous or vitamin D deficiency cause in chicks - what are the symptoms? Rickets Chicks cannot stand and have soft beaks
What causes bone deformations in the feet of broiler chicks? Abnormal calcium: phosphorous ratio
What is the calcium: phosphorous ratio required for poultry? 2:1 Except in breeding birds where it is higher, in particular laying hens
Give 2 ways in which calcium can be supplemented in the feed Calcium carbonate (limestone) Oystershell
Give a disadvantage of calcium supplementation in the feed Too much calcium makes feed unpalatable
Give 4 functions of phosphorous Bone growth Synthesis of phosphoproteins Synthesis of phospholipids Synthesis of nucleic acids
Give 2 consequences of phosphorous deficiency Reproductive failure Sub-optimal growth
Which dietary component is a good source of phosphorous? Cereals
How can phosphorous uptake from the diet be improved? 80% complexed as phytate Supplemented with bacteria derived phytase enzyme which can break this down
What is the advantage of supplementation to improve phosphorous uptake from the diet? Improved phosphorous utilisation so less need for inorganic phosphorous supplement Majority of inorganic phosphorous excreted so improved utilisation efficiency reduces costs and waste
Which 2 vitamins/minerals are linked with fertility? Vitamin E Selenium
Which vitamin is linked with embryo development? Vitamin B
What are chelated minerals? Inorganic minerals attached to a substrate (usually amino acid complex) to help overcome poor bioavailability
Give an example of a chelated mineral Organic selenomethionine made by feeding selenium to growing yeast cultures Improved bioavailability to inorganic sodium selenite
Give an advantage of chelated minerals More effective absorption
Give a disadvantage of chelated minerals Higher cost per active unit of mineral
What does an automatic feeding system involve? Automatic bird and feed weighers collect data Two component feeds (one high protein and one low) are mixed and fed according to the intake data
Which food form is generally used for poultry and why? Pelleted feed as leads to consumption of all components without any being 'picked out'
Which feed form is used in laying hens and why? Mashed feed Increases time spent feeding and reduces injurious pecking
Why are broiler breeders feed restricted? Ensures they pass on genetic traits for rapid growth but do not have excessive growth themselves This improves reproductive performance and chick survival as well as reducing mortality in female breeders
What feeding system is used for pullets? Feed quantity restricted to achieve breeders standard liveweight at point of lay
Which 2 factors are considered important when feeding pullets? Frame or skeleton size Body composition (fat, muscle and bone)
Why is point of lay liveweight important in laying hens? Determines egg size Affects laying performance Uniformity of liveweight in flock desirable Affects persistency
What happens to egg size as laying hens start to lay? Initially small and increase with age
Give 3 problems associated with excess liveweight in laying hens Reduced egg laying performance Possible embryo mortality High egg size in late lay, reducing quality and hatchability
What is the peak feed intake in hens? 165-170 g/hen/day
What happens to the feeding system for laying hens post-peak? Feed allowance reduced post-peak for best performance
What feeding system is used for breeding cockerels? Restricted intake to improve reproductive performance
What is the age of maturity in laying hens? First egg at 16-17 weeks
What is meant by persistency? Length of laying cycle
When are protein requirements highest in laying hens? High at point of lay then decrease
What is the requirement for the amino acid methionine? 390-430 mg/day
What is the requirement for the TSAA? 700-780 mg/day
What does the abbreviation TSAA stand for? Total sulfur amino acids
What is the requirement for the amino acid lysine? 800-900 mg/day
What is the requirement for the amino acid threonine? 550-620 mg/day
What is the usual lifespan of broiler birds? 30-42 days
Why is a high protein, easily digestible starter feed required for broiler chicks? Limited by early digestive capacity
For how long does enzyme supply limit digestive activity in broiler chicks? 3-5 days
For how long does bile supply limit fat digestion in broiler chicks? First 7 days
What is the constituent of a finisher feed? High energy, lower protein
How many diets are used through the lifespan of a broiler bird? 4-5
Why is wet litter problematic in broiler birds? Causes pododermatitis (foot pad burn) = down grading of carcass
What are 2 potential problems caused by optimising feed intake for a maximal feed conversion ratio and growth rate? Leg problems and weakness High mortality
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