Fish Hatchery Management - fisheries & aquaculture

236 FISH HAI'CHERY MANAGEMENT(2) Because the same formulation and quality of ingredients are used, thefeed will be consistent from one production season to the next.(3) Competitive bidding is possible for the specified feed.(A) fne feed can be monitored through a quality-control program'In using open-formula feeds, however, the buyer assumes full responsibilityfor feed performance because the manufacturer has followed contractedinstructions. This requires the buyer to have concise manufacturing andformula specifications, which must be updated periodically. Formula specificationsfor various diets are presented in Appendix F'A closed-formula feed is one in which the feed formulation is not disclosedto the buyer. These feeds are sold by private manufacturers and arealso referred to as "brand name" or proprietary feeds. The advantages ofthese feeds follow.(1) The manufacturer is responsible for the formulation'(2) The feed is generally a shelf item available at any time.(S) fhe diet may be lower in cost due to large-quantity production andthe option of ingredient substitution.(A) f ne manufacturer is liable for problems of poor production related tothe diet.However, the buyer has no control of the feed quality and the content ofthe feed largely is unknown. There may be unexpected variations betweenbatches of feed due to ingredient substitutions or formulation changes'Handling and Storing ProceduresFormulated fish feeds contain high levels of protein and oil with little fiber'These feeds are soft, fragile, and prone to rapid deterioration, especially ifoptimum handling and storage are not provided.Normally, the feeds are packaged in multiwalled paper bags to protectthe flavor, aroma, and color. The bags also reduce exposure to air, moisture,and contamination. Plastic liners are used in bags for feeds containingoil levels over l2% to eliminate oil seepage through the paper bags and toretard moisture uptake.Many fish producers receive their feed in bulk, storing it in large bulkbins (Figure 74). Whether feed is in bags or bulk, proPer handling andstorage procedures must be followed to protect the quality of the feed. Becausefish feeds are very fragile in comparison to feeds for other animals,up to 3% fines can be expected from normal handling. Excess fines are theresult of rough handling or poor physical characteristics of the feed. Do not