ANFF topic 3 part 2 (1)

Question 1

What do feed additives do?

Answer 1

• influence physical property of the pellet
• influence chemical properties of the diet
• affect animal performance
• influence quality of resulting prodcts

Question 2

State the types of feed additives.

Answer 2

• antimicrobial agents
• antioxidants
• binders
• colourants
• enzymes
• organic acids
• immunostimulants
• feeding stimulants
• probiotics
• hormones

Question 3

What is the function of antimicrobial agents?

Answer 3

• they have the capacity to kill or inhibit the growth of microorganisms

Question 4

Where can antimicrobial agents be obtained from?

Answer 4

• natural sources

- synthetic origin

Question 5

How are antimicrobials categorized and what are they categorized into?

Answer 5

• categorized by their use
• therapeutic
• prophylactic
• metaphylactic

Question 6

What is the function of therapeutic antimicrobial agents?

Answer 6

• treatment of established infections

Question 7

What is the function of metaphylaxis antimicrobial agents?

Answer 7

• aim to treat sick animals while also medicating others in the group to prevent disease (2 birds with 1 stone)

Question 8

What is the function of prophylaxis antimicrobial agents?

Answer 8

• preventive use of antimicrobials to prevent the development of infections
  (some animals may be more prone to certain diseases)

Question 9

How are therapeutic antimicrobial agents administered to farm animals?

Answer 9

• orally over short periods of time

Question 10

Why are a variety of antimicrobial compounds routinely added to manufactured feeds?

Answer 10

• prevent growth of moulds and microbial contaminants

Question 11

What are some antimicrobial agents for fish rearing?

Answer 11

• benzoic acid
• propionic acid
• sorbic acid
• calcium, potassium and sodium salts of these acids

Question 12

What are some antimicrobial agents used for pig rearing?

Answer 12

• bacitracin methylene disalicylate (BMD)
• bacitracin zinc
• carbadox
• lincomycin
• neomycin/oxytetracyline (antibiotic)

Question 13

What are some antimicrobial agents used for cattle rearing

Answer 13

• lasalocid
• maduramicin
• monensin
• narasin
• salinomycin
• semduramicin

Question 14

What ingredients are susceptible to autoxidation?

Answer 14

• fats
• oils
• vitamins
• pigments

Question 15

What can rancidity cause?

Answer 15

• 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)

Question 16

What are some synthetic antioxidants that are added to oils/ to complete diets to ensure protection from oxidation?

Answer 16

• 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

Question 17

Why is pre-gelatinized potato starch added to eel diets?

Answer 17

• increase the water stability of the dough

- provide energy

Question 18

What are the functions of binders?

Answer 18

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

Question 19

What percentage of the dry diet should be binding agents?

Answer 19

• 1 to 2% of the dry diet

Question 20

State some examples of binders used.

Answer 20

• bentonites
• lignosulphonates
• hemicellulose
• carboxymethylcellulose

Question 21

What is bentonite?

Answer 21

• 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)

Question 22

What is lignin sulfonate?

Answer 22

• 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

Question 23

What animals are colours and pigmentation agents primarily used for?

Answer 23

• aquatic animals

Question 24

What colours or pigmentation agents do fish and shrimp need?

Answer 24

• 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

Question 25

What are some examples of colours or pigmentation agents?

Answer 25

• astaxanthin

- canthaxanthin

Question 26

What are (exogenous) enzymes added into animal diets for?

Answer 26

• 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

Question 27

What are generally involved in the production of various enzymes?

Answer 27

• microorganisms
• bacteria
• fungus

Question 28

What are some examples of bacteria that produce enzymes?

Answer 28

• bacillus subtilis

- bacillus lentus

Question 29

What are some examples of yeast that produce enzymes?

Answer 29

• yeast

- asperigillus niger

Question 30

What are some examples of organic acids that can be supplemented?

Answer 30

• acetic acid
• butyric acid
• propionic acid
• citric acid
• formic acid
• lactic acid
• malic acid

Question 31

How do organic acids affect animal performance?

Answer 31

• 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)

Question 32

What do immunostimulants do?

Answer 32

• stimulate feed intake by animals

- inactivate natural and microbial products

Question 33

What are some examples of immunostimulants?

Answer 33

• B-glucan (β) –> harmful if overdose

- lactoferrin –> from mammalian milk

Question 34

What are some benefits of lactoferrin?

Answer 34

- immunostimulants
Appear to have:
- antibacterial properties
- antiviral properties
- antifungal properties
- anti-inflammatory properties
- antioxidant and immunomodulatory activities (increase immune response)

Question 35

What can stimulate the cell-mediated immune system (B-cells and T-cells)?

Answer 35

• lipopolysaccharides

- peptidoglycans

Question 36

What are some sources of polysaccharides?

Answer 36

• seaweeds
• chitin from invertebrate shells
• fungi and yeasts
• peptidoglycans
• herbal products such as essential oils

Question 37

What are probiotics?

Answer 37

• live and microbial dietary supplements that improve health

Question 38

What are prebiotics?

Answer 38

• non-digestible dietary ingredients that beneficially affect the host by
  - selectively stimulating the growth
  - activating metabolism of health-promoting bacteria in the GI tract

Question 39

What doe the microbiota in the gastrointestinal tract do?

Answer 39

important roles in:

• growth
• digestion
• immunity
• disease resistance to the host organism

Question 40

What are some types of hormones?

Answer 40

• growth hormone
• thyroid hormones
• gonadotropins
• prolactin
• insulin

Question 41

How are hormones supplemented to aquatic animals?

Answer 41

• dissolved in ethanol and sprayed onto the diet which is administered to the feed

Question 42

How are hormones supplemented to terrestrial animals?

Answer 42

• direct injection of hormone into the muscle