6669633
Description
Flashcards by Florence Edwards, updated more than 1 year ago
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Created by Florence Edwards
over 7 years ago
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| 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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