Potter et al., 1978. Poult. Sci., 57 (6): 1586-1593

Three replicate experiments each containing 24 diets in a 3 × 2 × 2 × 2 factorial design of four variables were conducted. Each diet was fed to nine male and nine female Large White turkeys from one day to seven weeks of age.

Body weights were increased 6.6 and 8.4% from adding 2.5 and 5.0% corn fermentation solubles to the diets, respectively. In the presence of 0, 2.5, and 5.0% corn fermentation solubles, 2.5% menhaden fish meal increased body weights 17.2, 10.1, and 5.7%, respectively. These data indicate that a common unidentified growth factor is about three times more concentrated in menhaden fish meal than in corn fermentation solubles.

From adding .05% DL-methionine to diets containing 0 and 2.5% menhaden fish meal, body weights were increased 5.7 and 2.9%, respectively. In contrast, body weights were increased 12.3 and 9.3% from adding 2.5% menhaden fish meal to diets containing 0 and .05% added DL-methionine, respectively. The addition of 2.5% menhaden fish meal supplied .02% more methionine and .01% less cystine to the diet by calculation. Therefore, fish meal increased body weights more than what could be accounted for by the methionine content of menhaden fish meal indicating that methionine is not the unidentified growth factor in menhaden fish meal.

Body weights were decreased 1.7%, an amount approaching significance, from adding 5% hydrolyzed feather meal to the diets. The diets containing 5% hydrolyzed feather meal contained .01% less methionine and .11% more cystine than diets without hydrolyzed feather meal by calculation. The .05% added methionine increased body weights 3.0 and 5.5% when diets contained 0 and 5% hydrolyzed feather meal, respectively. Therefore, hydrolyzed feather meal as a source of cystine to substitute for methionine was not effective in increasing body weights.