Document Type

Thesis - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)


Animal Science


The characteristics of the rachitogenic activity in isolated soybean protein were investigated. Day-old Broad Breasted White and/or Wrolstad Small White turkey poults were used. Levels of calcium, phosphorus and vitamin D3 were equal to or greater than National Research Council recommendations. Criteria used for evaluation were body weight gains, tibia ash, serum alkaline phosphate, serum inorganic phosphate and serum calcium. Trays containing dry isolated soybean protein spread to a uniform depth of two and one-half centimeters were placed in an autoclave and brought to 100oC by steaming and then 120oC for a designated period of time. The poults were kept in electrically heated wire-floor batteris. Water and food supplied ad libitum for the 4 week experimental periods. When serum values were studied, blood was taken by heart puncture from a representative sample of birds (five when possible) from each group. The serum was removed, placed in vials and stored at -20oC. Under the conditions of this investigation the following observations were made: 1. In general, poults fed untreated isolated soybean protein consistently exhibited rachitic symptoms, namely low tibia ash values and concomitant elevated serum alkaline phosphatase levels. The effects of the isolated soybean protein as measured by the other criteria were less consistent. 2. Subjecting isolated soybean protein to autoclaving destroyed its rachitogenic activity. Autoclaving proved to be the most effective way of reducing the rachitogenic property of isolated soybean protein. 3. Sixty minutes autoclaving time at 120oC proved optimum in destroying the rachitogenic activity of isolated soybean protein. 4. Substituting dibasic calcium phosphate, hydrous, U.S.P., for dicalcium phosphate, feed grade, markedly reduced the rachitogenic activity of the isolated soybean protein. 5. The inclusion of vitamin D3 levels four times the National Research Council recommendations was less effective than autoclaving in reducing the rachitogenic activity of isolated soybean protein. 6. It appears that the Broad Breasted White strain of poults is more susceptible to the onset of rickets as induced by untreated isolated soybean protein compared to the Wrolstad Small White strain. 7. Tibia ash gains should be studied when investigating the effect of ration treatments on tibia ash differences that might be present due to strain or nutritional effects. 8. The dilution of isolated soybean protein with autoclaved isolated soybean protein in the ratio of 2:2 was effective in reducing the rachitogentic activity of isolated soybean protein, however, it required one part of untreated isolated soybean protein to three parts of autoclaved isolated soybean protein to three parts of autoclaved isolated soybean protein to overcome the growth depressing action of isolated soybean protein. 9. The rachitogenic effect of isolated soybean protein exerts its greatest effect on the birds between 2 and 4 weeks of age. 10. Two-way interrelationships existed between autoclaving vitamin D3, autoclaving x source of calcium and phosphate, autoclaving x strain and vitamin D3 x strain; also there was a three-way interrelationship between autoclaving x source of calcium and phosphate x vitamin D3 level. 11. The variability in the Ca45 experiment was great and consequently raises a question as to the reliability of the data. Nevertheless, the data suggest that feeding autoclaved isolated soybean protein like increasing vitamin D3 does play a role in increasing calcium deposition by increasing calcium absorption and/or decreasing calcium secretion into the intestine.

Library of Congress Subject Headings

Poultry -- Feeding and feeds

Soybean as feed



Number of Pages



South Dakota State University