Feed Formulation and Manufacture

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Feed Formulation and Manufacture

• Dr. Joe M. Fox
• MARI-5314
• from Lovell, Akiyama and Dominy

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Computer Formulation of Feeds

• Least-cost feed formulation a feed formula that
  is both nutritionally-complete (within limits)
  and with a minimum ingredient cost (within
  limits)
• now-a-days is developed and completed through the
  use of computers using linear-programming
  software
• typical packages Brill, Mix-it, Agridata
• used by most feed mills/manufacturers

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Least-cost Formulation

• Least-cost feed formulations require that the
  following information be provided
• cost of feed ingredients
• nutrient content of feed ingredients
• nutritient requirement of the animal
• availability of the nutrient to the animal
• minimum-maximum restrictions on levels

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Least-cost Formulations

• Costs of feed ingredients and nutrient content
  are fairly available for most commercial
  feedstuffs
• costs can be evaluated on a daily basis
• nutrient requirements are fairly well known
• the most critical piece of information regards
  digestibility/availability of nutrients within
  the feed ingredient
• various indices DE, ME, APD, etc.
• these can be set in formula w/restrictions

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Least-cost Formulation

• these are nutrient and ingredient restrictions
  that have been used for least cost formulation of
  catfish feeds
• theoretically, protein level does not have to be
  restricted if essential amino acid requirements
  are well-known
• for catfish, if the minimum requirements for
  lysine and the sulfur-containing AAs are met,
  other EAA requirements are also met

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Least-cost Formulations

• Other restrictions minimum available phosphorus
  and digestible energy
• only maximum calcium is typically considered due
  to availability in water
• whole fish or other animal protein sources have
  been shown beneficial for catfish feeds
• cottonseed meal is restricted to 10 due to
  gossypol (protein) content (toxic)
• xanthophyll content often restricted due to it
  causing yellow discoloration of fish at high
  concentrations

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Least-cost Restrictions for Shrimp Feeds
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Least-cost Formulations other restrictions

• Limitations to computer formulations exist and
  should be recognized
• where the computer says its ok, the experienced
  formulator knows differently
• example too high fat content for pelleting
• example sorghum might be as good as corn in an
  extruder, but not a pelletizer
• this is why advantages are maximized when a
  number of options are available

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Computer Formulation of Feeds

• Originally, the development of feed formulations
  was a real task
• mathematical models for formulating
  nutritionally-adequate diets at lowest cost were
  available
• however, everything had to be hand calculated
• feed formulation the preparation of
  nutritionally-complete diets for feeding animals

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Least-cost Formulations other restrictions

• In many cases, logistics of obtaining ingredients
  and their storage limit the number of ingredients
• availability of feedstuffs is not as important as
  having the option to substitute
• must also take into consideration the physical,
  palatability, and toxicological properties of the
  feed
• nutrient availability also varies

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Least-cost Formulations restrictions

• As mentioned, most least-cost formulae are
  derived by linear programming
• it has its disadvantage in that it uses data out
  of the NRC handbook for fixed, maximum growth
  rates
• it does not take into consideration optimum
  return on growth for various feed nutrient
  concentrations
• this requires regression analysis
• regression analysis is now being integrated into
  poultry formulae, probably not yet available for
  fish

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Part 2 Feed Production

• Largely provided by Wenger, Inc. and Akiyama

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Feed Production

• Two major methods pelletizing and extrusion
• steam pelleting produces a dense pellet that
  sinks rapidly in water
• extrusion produces a low density feed particle
  that has a tendency to float
• steam pelleting uses moisture, heat and pressure
  to agglomerate ingredients into larger,
  homogenous particles
• steam added to the ground feed mash (mix)
  partially gelatinizes starch, binding ingredients

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Pelletizing Feeds

• Generally, steam is also added prior to passing
  the mash through the pellet die
• this increases its moisture content to 15-18
• temperature goes up to about 85oC
• steam pelleted feeds must be firmly bonded for
  satisfactory stability in water
• starch is important for adequate binding
• fat and fiber are antagonistic to process
• supplemental fat not added if pelleting

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Pelletizing Feeds

• All conventional pellet mills include the
  following equipment
• variable speed feeder
• conditioning chamber
• die and roller assembly
• speed reduction device
• prime mover
• base
• the variable speed feeder provides a continuous,
  controlled flow of feed mix

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Pelletizing Feeds conditioning

• The conditioning chamber is actually a mixer with
  either fixed or movable paddles
• conditioning is accomplished by the addition of
  controlled amounts of steam
• steam liberates natural oils, partially
  gelatinizes starches, increases temp, increases
  moisture
• starch gelatinization loss of birefringence or
  the irreversible rupture of the native secondary
  bonds in the crystalline region of the starch
  granule
• the speed reduction device is added to reduce
  motor speeds to that of the die head
• this is absolutely critical for the production of
  consistent-sized particles

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Pre-conditioning
gelatinization process
machine
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Sinking vs. Floating Feeds
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Typical Pellet Mill
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Typical Pellet Mill Process Flow
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Typical Pellet Mill
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Die Assembly
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Comparison extrusion vs. pelleting
Process flow diagrams
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Typical Extruder (side view)
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Comparison pelletized vs. extruded feeds
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Pellet Comparison continued
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Price Comparison
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Pellet Appearance

• Feed pellets should contain no fractures
• fractures are indicative of poor processing and
  conducive to poor water stability
• fractures allow water to seep into pellet more
  rapidly, pellet hydrates, breaks
• feed pellets should not clump together
  (indivative of poor drying, results in poor
  nutritional quality, stability)
• fines from bags should total less than 2
• result you lose money, get poor water quality

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Feed Pellet Size

• What feed pellet size you feed is determined by
  age of animal
• size of particle must be the one most efficient
  for location and consumption by animal
• proper nutrient package, right size,
  well-distributed
• smaller pellets usually imply easier distribution
• feed particles range in size from less than 50 µM
  to over 1/8 in. diameter

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Feed Pellet Size

• Larvae lt50, 50-125, 250, 500 µM, according to
  larval substage
• postlarvae flakes, fine crumbles (500 µM)
• juveniles to 2-3 g medium crumble (1mm) to
  coarse crumble (2mm)
• 3-6 g short pellet (3/32 x 2-4 mm)
• 6-10g medium pellet (3/32 x 6 mm)
• 10-16 g long pellet (3/32 x 10 mm)
• over 16 g 1/8 in. diam, various lengths
• point one pellet per shrimp per feeding

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Feed Pellet Size

• For a 2mm x 6mm pellet, you have approximately 1
  million pellets per 100 lb bag
• if your 10 ha pond has 2 million shrimp in it (20
  per sqm), feeding two 100 lb bags gives each
  shrimp 1 pellet/feeding
• 20 pellets per sqm pellet density