What is a feed additive?
any compound used in a ration that is not normally occurring in those feeds and does not meet a known nutrient requirement
What are the two main functions of feed additives?
- Enhance effectiveness of nutrients
2. Improve storage and handling of nutrients (prevent spoilage and prevent contamination)
What are the functions of preservatives?
protect nutrients from damage
What is “therapeutic” use of antibiotics?
Using them for the treatment of sick and or diseased animals.
What is “prophylactic” use of antibiotics?
Use of antibiotics to prevent infection
What is “growth promoting” use of antibiotics?
Antibiotics in sub therapeutic levels of improve production and reduce diseases.
Provide some examples of how sub-therapeutic levels of antibiotics improve productivity:
- decrease pathogenic bacteria
- decrease harmful metabolites
- decrease microorganisms competing for nutrients
- Increase bacteria that synthesise useful compounds
- Structural Changs to GIT that increase nutrient uptake
What are ionophores ?
Coccidiostat (protozoan parasites) related to antibiotics (non-therapeutic antibiotics.
How do ionophores improve feed conversion?
increasing propionate and reducing CH4.
What species can ionophores not be safely used in?
ionophores cannot be safely used in horses. They will lead to the development of fatal cardiac arrhythmias and weakness
The ionophore Salinomycin is safe for use in chickens but not safe in what other breed of poultry?
Turkeys
Name the species and the reasons that the antibiotic Virginiamycin is used in:
- pigs and chickens - prophylactic antibiotic
- reduce the risk of rumen acidosis in cattle and sheep
- reduce the risk of hind-gut acidosis and laminitis in horses
How does virginiamycin assist in hind-gut acidosis in horses?
- Fermentable carbohydrate in the hind-gut
- Proliferation of lactate producing bacteria
- pH decline
- proliferation of lactate-producing bacteria but the death of lactate utilising bacteria
What are a couple of alternatives to the use of antibiotics?
- The use of organic acids
- Minerals
- Probiotics - yeast/bacteria
- Plant extracts
- Pre-biotics
What is the effect of exogenous feed enzymes and what species are they commonly used in?
- Commonly used in chicken, pig and dog diets
2. Increase NSP (non-starch-polysaccharide) breakdown in the gut, thus improving digestive efficiency
What is the effect of the repartitioning agent Beta-agonists?
Bind to adrenalin receptors and decrease fat (increase lipolysis, decreased lipogenesis) and increase muscle (by decreasing amount of protein degradation)
What is a side effect of Beta-agonists?
Tougher meat
What are the three types of hormonal growth promotants?
- Endogenous hormones
- Exogenous products
- Synthetic hormones
