INSPECTION OF COMMERCIAL FEEDSTUFFS 



27- 



The preceding table contains the determined content of carotene and riboflavin 

 in commercial mashes found in Massachusetts markets. The list is in no way 

 complete and simply represents such samples as were picked up by Control 

 Service inspectors and were available at the time the work was undertaken. 



Carotene is an organic substance from which vitamin A can be formed by 

 biological processes. One part of carotene is equivalent to 1.6 parts of vitamin A. 

 The principal source of carotene in commercial mashes is alfalfa meal, which 

 varies widely in carotene content. It is believed that some feed mixers use very 

 little care in the selection of al.alfa. 



It should be understood that the assays here reported are for carotene and 

 that low results do not necessarily indicate a vitamin A deficiency as dependence 

 may have been placed on other sources for a part of the vitamin A. All of the 

 feeds examined declared cod liver or other fish oils as an ingredient, both of which 

 contain vitamin A. 



Titus, in an article published in the 1939 edition of the United States Depart- 

 ment of Agriculture Year Book, suggests that if a feed is to be stored for more 

 than a month not less than 70 per cent of the vitamin A should be derived from 

 plant sources, the reason being that vitamin A in oil carriers when incorporated 

 in a mixed feed is much more unstable than carotene derived from such plant 

 sources as alfalfa and corn. Carotene in alfalfa is also unstable when the alfalfa 

 is not produced and stored in such a way as to conserve the carotene. 



The assays for riboflavin (vitamin G) indicate that furnishing a sufficiency of 

 this vitamin is not a serious problem. Its principal sources are distillers' residues 

 or by-products, dried yeast, dried milk and milk by-products, alfalfa meals, and 

 numerous commercial blends which depend upon some of the above listed as a 

 riboflavin ingredient. Riboflavin is more stable than either carotene or vitamin A. 



Following is a compilation of vitamin A and riboflavin requirements for poultry 

 taken from the 1939 United States Department of Agriculture Year Book, found 

 in the article "Practical nutritive requirements of poultry" by Harry W. Titus. 



*If the feed is to be stored for more than a month before it is fed, not less than 70 per cent 

 of the vitamin A should be derived from plant sources. 



For the benefit of feed chemists who may be interested the methods used in 

 determining carotene and riboflavin follow. 



