- Although aquaculture dates back from the earliest parts of human history
in Asia, Europe and in the Pacific Islands (Stickney, 2000), it is only in
the last few decades that aquaculture has begun to catch up with the rest
of animal agriculture in terms of the science of feed manufacture and nutrition.
- Aquaculture currently represents the fastest growing segment of agriculture
and the animal feed manufacturing industry, particularly in mainland China
and the Asian region where over 90% of global aquaculture production is currently
realized (Akiyama & Hunter, 2000; Tacon and Forster, 2000).
- The manufacture of aquaculture feeds presents special challenges to the
traditional feed milling concepts due to the aquatic medium in which the feed
has to be delivered and ingested, and to the small size and variety of the
animals being cultivated. For example, slow feeding animals like marine shrimp
require the production of feeds which are physically stable in water for several
hours. Moreover, farmed aquatic animals are generally considerably smaller
than their terrestrial counterparts, such as pigs, poultry and cattle; marine
shrimp reaching a marketable size at only 20 grams.
- It follows therefore, that the production of feeds for aquatic species requires
a higher degree of precision be it the particle reduction of ingredients to
sizes as low as 50 microns, or the precise mixing of as many as four dozen
ingredients in a feed which is of minute size in comparison to its terrestrial
counterpart (for general review see Akiyama and Tan, 1991; Barrows, 2000;
Barrows & Hardy, 2000; Bartone, 1999; Dominy, 1994; Dominy et al., 1994;
Erickson, 2000; Langdon, 2000a, 2000b; McEllhiney, 1994; Rokey, 2001; Tan
& Dominy, 1997).
- These are the compelling reasons why many new feed mills are dedicated
to aquatic feeds and often employ human food standards in production. Along
with the higher standards of production come more expensive and higher quality
standards for the ingredients used to prepare feeds for what are often very
sensitive production animals (Boonyaratpalin & Chittiwan, 1999; Barrows
& Hardy, 2000).
- The principles of the Hazard Analysis and Critical Control Point (HACCP)
procedure may have application in aquaculture (FAO/NACA/WHO, 1999; Nickelson,
1998; Reilley & Kaferstein, 1997) and aquaculture feed milling (Hardy,
1991) if they are genuinely cost effective in terms of providing scientifically
sound protection to animal and human health. Critical control points will
have to be identified and in this regard FAO/WHO’s Draft Code of Practice
for Fish and Fishery Products (FAO/WHO, 2000a), which includes a special section
(section 16) on aquaculture production, provides a model for possible adaptation.
- Good Manufacturing Practices (GMP) are represented in the balance of procedures
outlined in these technical guidelines, and it is this use of GMP employed
worldwide which has proven successful in production of wholesome and effective
feeds (Whitehead, 1998). As a result, adverse health impacts on humans or
animals from compound animal feeds has been negligible (FAO, 1998).
- While cleanliness of ingredients is important, ultimately the wholesomeness
of feeds will depend upon the quality of ingredients (Jones, 2000) as well
as the application of a treatment or process to eliminate disease producing
organisms (i.e., Salmonella; Anon, 2001; FAO, 1998; D’Mello, 2001; Gill,
1999; Machin, 2001; Pearl, 2000; Said, 1996; Van De Venter, 2000) and to prevent
possibility of recontamination after pelleting or extrusion is completed (Beumer
and Van der Poel, 1997).
- It is on-farm management (husbandry) of cultured species which has the
greater impact on product wholesomeness, including health of the animals and
the human consumers. Pathogen destruction and reduction of toxicants involves
a partnership at all levels of production from field to feed mill, to farm,
to packer and processor, as well as care in preparation by the final consumer
(FAO, 1998; FAO/NACA/WHO, 1999; Howgate, 1998; Spencer Garrett, dos Santos
& Jahncke, 1997; Sutmoller, 1998).
- Research is needed to demonstrate management benefits of quality assurance
(Q/A) programs and pathogen negative feed. Traditional microbiological tests
for pathogens are typically too slow to make HACCP practicable for aquafeeds
(Cahill, 2000; FAO/WHO, 1995; FAO/WHO, 2000b).
- Indeed, while GMP may not meet the entire definition of HACCP, parts of
GMP do meet some of the criteria for an overall HACCP programme, and it is
important that aquafeed feed millers continue to use a programme which will
minimize adverse animal and human health effects while continually improving
feed production (Lobo, 2000). Contamination of feed after processing, by birds
and rodents in particular, may be the single greatest hurdle to overcome (Fedorka-Cray
and Lautner, 1996).
- Although much further research still remains to be undertaken so as to
determine the precise dietary nutrient requirements of a wide variety of cultured
aquatic species (Forster, 2000; Lovell, 1997; Shiau, 1998), as this information
becomes available mill design and mill processing changes are inevitable.
For that reason the aquatic feed miller of today must maintain flexibility
within their mills and an awareness that changes are taking place as these
guidelines are being written.
