FISHERY BULLETIN: VOL. 71, NO. I 



Table 8. — Unidentified growth factor response from various sources of condensed fish 



solubles. 



1 Only vegetable sources used. 

 * Statistically significant {P<0.05). 



A compilation of recent reports (Table 8) in 

 which the phenomena of unidentified growth 

 factors in condensed solubles were studied brings 

 out several interesting points. First, these data 

 indicate that significant unidentified growth re- 

 sponses are still being observed even when every 

 effort is made to supply all known nutrients in 

 the experimental diets. Secondly, growth re- 

 sponse seems to be maximal when the solubles 

 content ranges from 2 to 5 % of the diet and when 

 these diets are fed to chicks for 14 to 21 days 

 beginning with day-old birds. Growth responses 

 tend to diminish as the birds become older. Fur- 

 thermore, growth stimulations are consistently 

 observed with battery-reared chicks fed conven- 

 tional feeds or highly purified rations. There- 

 fore, it is evident that stress, such as that found 

 in field conditions, may not be necessary to ob- 

 tain a significant growth response from feeding 

 condensed fish solubles. 



An interesting series of experiments conducted 

 by Harrison and Coates (1964) showed that sig- 

 nificant growth responses were obtained from 

 chicks whose parents were maintained on con- 

 ventional rations containing animal protein or 

 all-vegetable rations. In fact, the average 

 growth response was greater when the conven- 

 tional diets were fed. In comparing the effects 

 of feeding 5% solubles to conventional or germ- 

 free chicks, a significant response was observed 

 only with the conventional birds. This indicates 

 that the presence of microbes does influence the 

 magnitude of the growth response. However, 



these workers observed that the addition of a 

 small amount of sterilized or fresh droppings to 

 the diet caused a significant growth depression 

 which could be counteracted by feeding fish sol- 

 ubles. 



Miller and Soares (1972) have conducted some 

 detailed experiments designed to study unident- 

 ified growth factors in fish solubles. They used 

 virtually a complete chemically defined diet 

 (Table 9) except for the sources of essential fat- 

 ty acids, which were supplied as purified oils. 

 The amino acid mixture was patterned after that 

 of Dean and Scott (1965). The vitamins, min- 

 erals, and antioxidant were supplied in sucrose- 

 based premixes (Miller and Soares 1972). 



Table 9. — Basal composition for crystalline amino acid 

 diet used to study unidentified growth factor responses 

 in chicks.^ 



Ingredient 



Amount 



Sucrose 



Crystalline amino acid^ 



Antioxidant premix^ 



Celluilose 



Safflov^er oil 



Menhaden oil 



CaCOa 



CaHP04 



Mineral mix' 



Vitamin mix'' 



Choline CI mix 



glkg 



502.3 



225.3 



2.0 



80.0 



50.0 



10.0 



5.0 



26.9 



28.5 



50.0 



20.0 



1,000.0 



1 Miller and Soares (1972). 



a Dean and Scott (1965). 



* Santoquin premixed one part with nine ports sucrose. Reference to 

 trade names does not imply endorsement by the National Marine Fisheries 

 Service, NOAA. 



262 



