SCARES ET AL.: CONDENSED FISH SOLUBLES 



in the feces and urine. This parameter is uni- 

 versally accepted among poultry nutritionists 

 as a valid estimate of dietary energy content 

 and is very important in formulating least cost 

 poultry rations. 



Owing to the limited data available in. the lit- 

 erature on the ME value of condensed fish sol- 

 ubles, Cuppett and Soares (in press) have con- 

 ducted investigations concerning this property. 

 Data were gathered on 10 of the menhaden sol- 

 ubles samples used in the analytical studies dis- 

 cussed earlier. The experimental design with a 

 few modifications for convenience was similar 

 to that used by Potter and Matterson (1960) 

 for various common feed ingredients. In these 

 experiments, eight 3-week-old White Rock broiler 

 cockerels were placed in each battery pen. Each 

 diet was fed to two groups of chicks for 5 days 

 and excreta samples were collected for 3 days. 

 Chromic oxide was incorporated in the diet at 

 the 1% level as a marker. Fish solubles were 

 fed at 0, 5, 10, and 15% levels. Analyses for 

 proximate composition and gross energy were 

 made on all diets and excreta samples. 



The average ME value was 2.03 kcal/g which 

 is somewhat higher than the calculated figures 

 usually presented in feed analysis tables. These 

 results are in good agreement with the data re- 

 ported by Matterson et al. (1965) and Chu and 

 Potter (1969) (Table 7). The ME value of all 



UNIDENTIFIED GROWTH FACTOR (S) 



The major contribution of condensed fish sol- 

 ubles is the unknown factor necessary for max- 

 imum growth of poultry and hatchability of eggs. 

 Considerable evidence has been presented to 

 demonstrate the existence of a stable unknown 

 essential in condensed fish solubles. Combs, 

 Arscott, and Jones (1954) indicated that the 

 growth response obtained with arsanilic acid 

 occurs only in the presence of the fish factors. 

 The so-called fish factor is believed by Tamimine 



(1955) to be two components: one, organic in 

 nature and the second, inorganic. Similar re- 

 sults were obtained by Steinke, Bird, and Strong 

 (1963). 



Combs et al. (1954) also reported a lack of 

 chick growth response from fish solubles fed 

 with penicillin. Similarly, Barnett and Bird 



(1956) found a lack of response with high levels 

 of chloretetracycline. The conclusion is that the 

 activity of the fish solubles occurs only in the 

 presence of certain intestinal microorganisms. 

 They also obtained no growth response when 

 chicks were in new uncontaminated buildings. 

 Actually, their bioassay method developed for 

 evaluating the fish factor is dependent upon the 

 ingestion of poultry excreta by the chicks on test. 

 This would seem to confirm that beneficial bac- 

 teria flourish in the intestines of poultry only in 



Table 7. — Metabolizable energy and protein and fat digestibility eval- 

 uations of fish solubles in diets fed to young broilers and turkeys. 



Source 



Experimental Metabolizamie 

 animal energy 



Fat 



digestibility 



Nitrogen 

 digestibility 



Matterson ef al. (1965) Chicken 



Chu and Potter (1969) Turkey 



Cuppett and Soares (in press) Chicken 

 Average 



kcal/g 

 2.094 

 2.223 



2.030 ±0.23 

 2.12 



97.7 



88.7 ± 2.48 



93.2 



67.'2 

 56.2 

 62.0 



3.70 



three reports averages 2.12 kcal/g (962 kcal/lb) 

 with fat and protein digestibilities of 93.2 and 

 62.0%, respectively. It appears that much of 

 the problem with lower calculated values report- 

 ed in the various feedstuflfs tables is due to 

 underestimating the fat content of fish solubles. 



the presence of the fish factor. Similar evidence 

 exists for the essentiality of the fish factor for 

 the hatchability of chicken and turkey eggs. 

 However, there are some contradictory reports. 

 The reason for the differences in the observa- 

 tions has not yet been elucidated. 



261 



