ANSC 260

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ANSC 260
2012-12-11 17:52:40
Anti nutritional Factors

Chapter 10
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  1. Anti-nutritional factors
    Natural components of feedstuff that interfere with the digestion, absorption or utilization of nutirents or energy
  2. Toxins
    • A poisionous substance produced within living cells
    • Organic, inorganic, mycotoxins, agricultural chemicals
  3. Contaminants
    • Material inadvertently included in feed
    • toxic plants
    • toxic plant components
    • microbial (bacteria/fungal) toxins
    • drug residues
    • pesticides
    • pollutants
  4. General signs of toxicity at low levels
    • Growth rate problems
    • Reduction in animal vigor
    • Reduction in fertility
    • Induced abortions
    • Birth defects
    • Plants often have more than 1 ANF or toxin
    • Ruminants can often metabolize many toxins & ANF
  5. Fibre
    • Most common ANF for monogastrics
    • -effect on feed passage
    • -access of enzymes to substrates in lumen of GI
    • -movement of released nutrients from food particles to absorptive substrates
  6. Pant ANF
    • Most poisonous plants unpalatable
    • -only consumed in drought, spring, or overgrassed pastures
  7. Plant ANF physiolocial responses vary with
    • Species of plant
    • Stage of lifecycle
    • Part of plant
    • Soil type
    • Processing
    • Animal species
  8. Organic ANF - Protein
    • Pretease inhibitors (mainly legumes, heat treatment works)
    • Lectines (beans & legumes, causes cells to clump, reduces absorption, heat treatment works)
    • Anitgenic proteins (allergy, elicit humoral immune response, problem with feeding/withdrawl/feeding)
  9. Phenolics - Organic Toxins
    • Tannins (bitter & stringent: cross-link and become insoluble)
    • Gossypol (monogastrics, cardiac irregularity, anemia, infertility: removed by solvent extraction)
    • Sinapine (phenyl)(bitter, some chickens back TMA oxidase)
    • Cynogenic glyosides (cytochrome oxidase cleaves to form free sugar & HCN)
    • Giotrogenic gylcosides (goitrin interferes with thyroid activity and iodine metabolism)
    • Coumarin (vit. K antagonist)
    • Vicine and convicine (metabolized into toxic product, RBC fragility)
    • Saponins (CHO bound to steriod, bubbling in rumin)
  10. Other Organic Toxins
    • Phytoestrogens (plant steriols resemble estrogen)
    • Metal-binding agents (phytate: interfere with P availability)(oxylate: binds to Ca)
    • Plant alkoloids (nitrogen component: problem for ruminants)
    • Blue-grren algae
  11. Inorganic poisons
    • Nitrates; green leaves, heavy N fertilizers
    • Uninary calculi; high K or P intake, incorrest Ca:P ratio, silica
    • Selenium toxicity; blind staggers, loss of hair, sloughing of hooves. paralysis, respiratory failure
    • Grass tetany: hypomagnesemia (too much P), rapidly growing lush pasture, temp or other stresses, organic acid in plants
  12. Mould growth requirements (5)
    • Available nutrients
    • Insect damage/disrupted seed coat
    • Moisture >14% RH>70%
    • Oxygen
    • Specific temps.
  13. Most important species in regards to mycotoxin
    • Penicillium spp
    • Aspergillus spp
    • Fusarium spp
    • Claviceps spp (ergot)
  14. Concern with mycotoxins in livestock feed
    Concentration in DDGS
  15. Aflatoxin
    • from Aspergillus flavus
    • -typical mold requires 24-40 C
    • -greater in tropical areas, shipped worldwide
    • Corn, peanuts, cottos=nseed
    • Considered storgae mold
    • Acute toxicoses, jaundice, cirrhosis of liver
    • -lower dose, decreased appetite, weight and unthriftiness
    • -reduce by feeding higher protein
    • World prominence in 1960s
    • Highly potent
    • High affinity for nucleic acids
    • -interferes with protein synthesis, immunosuppressive & carconiogenic
    • Animals metobolize toxins, but metabolites may still be toxic
  16. Fusarium spp
    • Colonizes in field, toxin in storage
    • -affects storage, temperate clomates
    • zearalenone - causes hyperestrogenism and infertility
    • tricothecenes - inhibit translation during protein synthesis
  17. Ochratoxin
    • From aspergillus, Penicllium spp
    • Cooler climate
    • Serius residue in feed chain
    • High affinity for enzymes involved in CHO and protein metabolism
  18. Alkaloids
    • Ergot - fungus develops in seed ovary
    • Ergotism - 3 types
    • -gangrenous: vasoconstriction due to smooth muscle constriction
    • -convulsize: neurotoxic effect
    • -hallucinogenic
  19. Medicinal uses for ergot
    • Reduce hemorrhages following childbirth
    • Control headaches?
  20. To use ergot
    • Clean it and dilute it
    • Don't fed to pregnant animals
    • Limit o 0.1% of diet