ANFF topic 3 part 2 (1) Flashcards
What do feed additives do?
- influence physical property of the pellet
- influence chemical properties of the diet
- affect animal performance
- influence quality of resulting prodcts
State the types of feed additives.
- antimicrobial agents
- antioxidants
- binders
- colourants
- enzymes
- organic acids
- immunostimulants
- feeding stimulants
- probiotics
- hormones
What is the function of antimicrobial agents?
- they have the capacity to kill or inhibit the growth of microorganisms
Where can antimicrobial agents be obtained from?
- natural sources
- synthetic origin
How are antimicrobials categorized and what are they categorized into?
- categorized by their use
- therapeutic
- prophylactic
- metaphylactic
What is the function of therapeutic antimicrobial agents?
- treatment of established infections
What is the function of metaphylaxis antimicrobial agents?
- aim to treat sick animals while also medicating others in the group to prevent disease (2 birds with 1 stone)
What is the function of prophylaxis antimicrobial agents?
- preventive use of antimicrobials to prevent the development of infections
(some animals may be more prone to certain diseases)
How are therapeutic antimicrobial agents administered to farm animals?
- orally over short periods of time
Why are a variety of antimicrobial compounds routinely added to manufactured feeds?
- prevent growth of moulds and microbial contaminants
What are some antimicrobial agents for fish rearing?
- benzoic acid
- propionic acid
- sorbic acid
- calcium, potassium and sodium salts of these acids
What are some antimicrobial agents used for pig rearing?
- bacitracin methylene disalicylate (BMD)
- bacitracin zinc
- carbadox
- lincomycin
- neomycin/oxytetracyline (antibiotic)
What are some antimicrobial agents used for cattle rearing
- lasalocid
- maduramicin
- monensin
- narasin
- salinomycin
- semduramicin
What ingredients are susceptible to autoxidation?
- fats
- oils
- vitamins
- pigments
What can rancidity cause?
- palatability problems in feed (pellets start to become brittle and break easily)
- loss in vitamin potency
- colour strength of pigments to become faint (lose colour)
What are some synthetic antioxidants that are added to oils/ to complete diets to ensure protection from oxidation?
- Ethoxyquin –> limit to 0.02% of the lipid content
- Butylated Hydroxyanisol (BHA) –> limit to 150 mg/kg diet
- Butylated Hydroxy Toleune (BHT) –> limit to 150 mg/kg diet
Why is pre-gelatinized potato starch added to eel diets?
- increase the water stability of the dough
- provide energy
What are the functions of binders?
Improve the efficiency of the feed manufacturing process
- reduce feed wastage
- produce a water-stable diet
- enable the feed mixture to pass through the pellet dies more easily
- increase output and horse power efficiency of the feed mill
- increase pellet hardness for the production of a durable pellet
What percentage of the dry diet should be binding agents?
- 1 to 2% of the dry diet
State some examples of binders used.
- bentonites
- lignosulphonates
- hemicellulose
- carboxymethylcellulose
What is bentonite?
- binder
-naturally occurring clay consisting mainly of trilayered aluminium silicate - swells when added to water
Added to dry, compressed fish feeds at no more than 2% : - act as a binding agent
- act as a lubricant (increase pellet mill production rates and pellet mill die life)
What is lignin sulfonate?
- binder
- product of the wood pulping industry
Purpose: - helps in pellet binding
- reduces fines (cracks in pellets)
- permits the addition of more steam during the manufacture of compressed pellets
- added at up to 4% as a pelleting aid in dry, compressed (steam-pelleted) feeds
What animals are colours and pigmentation agents primarily used for?
- aquatic animals
What colours or pigmentation agents do fish and shrimp need?
- carotenoids (orange) & xanthophylls (yellow)
- they use oxygenated carotenoids and xanthophylls to produce pigmentation of their flesh, skin and eggs
- aquatic animals cannot bio-synthesize carotenoids
- depend entirely on their supply of carotenoids
What are some examples of colours or pigmentation agents?
- astaxanthin
- canthaxanthin
What are (exogenous) enzymes added into animal diets for?
- improved feed efficiency
- benefit animals that lack certain digestive enzymes during early development or throughout their life
- enhances breakdown and absorption of nutrients (especially fat & protein)
- increases feed intake, weight gain and feed gain ratio
- reduces ammonia production (esp, for fish)
- improves nutrient digestibility
What are generally involved in the production of various enzymes?
- microorganisms
- bacteria
- fungus
What are some examples of bacteria that produce enzymes?
- bacillus subtilis
- bacillus lentus
What are some examples of yeast that produce enzymes?
- yeast
- asperigillus niger
What are some examples of organic acids that can be supplemented?
- acetic acid
- butyric acid
- propionic acid
- citric acid
- formic acid
- lactic acid
- malic acid
How do organic acids affect animal performance?
- limits the growth of microorganisms in feed (instead of adding antibiotics –> may not be good for humans)
- increasing availability of nutrients
- altering the animal’s gastrointestinal tract function and energy metabolism (because the pH has been changed)
What do immunostimulants do?
- stimulate feed intake by animals
- inactivate natural and microbial products
What are some examples of immunostimulants?
- B-glucan (β) –> harmful if overdose
- lactoferrin –> from mammalian milk
What are some benefits of lactoferrin?
- immunostimulants Appear to have: - antibacterial properties - antiviral properties - antifungal properties - anti-inflammatory properties - antioxidant and immunomodulatory activities (increase immune response)
What can stimulate the cell-mediated immune system (B-cells and T-cells)?
- lipopolysaccharides
- peptidoglycans
What are some sources of polysaccharides?
- seaweeds
- chitin from invertebrate shells
- fungi and yeasts
- peptidoglycans
- herbal products such as essential oils
What are probiotics?
- live and microbial dietary supplements that improve health
What are prebiotics?
- non-digestible dietary ingredients that beneficially affect the host by
- selectively stimulating the growth
- activating metabolism of health-promoting bacteria in the GI tract
What doe the microbiota in the gastrointestinal tract do?
important roles in:
- growth
- digestion
- immunity
- disease resistance to the host organism
What are some types of hormones?
- growth hormone
- thyroid hormones
- gonadotropins
- prolactin
- insulin
How are hormones supplemented to aquatic animals?
- dissolved in ethanol and sprayed onto the diet which is administered to the feed
How are hormones supplemented to terrestrial animals?
- direct injection of hormone into the muscle
