4 



Nutrition and Feeding 



Nutrition 



Nutrition encompasses the ingestion, digestion, and absorption of food. 

 The rearing of large numbers of animals in relatively restricted areas, 

 whether they be terrestrial or aquatic, requires a detailed knowledge of 

 their nutritional requirements in order that they can be provided a feed 

 adequate for their growth and health. There has not been the emphasis on 

 rearing cultured fish as a major human food source that there has been for 

 other livestock. Also, the quantity of fish feed required by hatcheries and 

 commercial fish farms has not been sufficient to justify feed companies or 

 others to spend more than a minimal amount of money for fish nutrition 

 research. As a result, an understanding of fish nutrition has advanced very 

 slowly. 



Biologists first approached the problem of feeding cultured fish by inves- 

 tigating natural foods. Several species still must be supplied with natural 

 foods because they will not eat prepared feeds. However, as large numbers 

 of fish were propagated and more and more fish culture stations estab- 

 lished, it became uneconomical or impractical to use natural feeds. Because 

 of the limited supply and uncertain nature of artificially cultured natural 

 food organisms, fish culturists turned to more readily available and reliable 

 food supplies. Glandular parts of slaughtered animals were among the first 

 ingredients used to supplement or replace natural feeds. 



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