DIFFERENTIAL AGE RESPONSE OF TURKEYS TO PROTEIN AND SORGHUM TANNIN LEVELS

Three experiments were conducted to determine the effect of protein and dietary sorghum tannin levels on weight gain (WG), feed conversion (FC), and pancreas weight (PW) of female turkeys from Day 1 to 12 wk of age. Two protein levels (100 and 85% of NRC, 1984) and five tannin levels (0, .49, .98, 1.47, and 1.96%, expressed as percentage catechin equivalents) in a factorial arrangement of treatments were used in all experiments. Turkeys were fed the dietary treatments from Day 1 to 4 wk, 4 to 8 wk, and 8 to 12 wk in Experiments 1, 2, and 3, respectively. No significant (P > .05) interaction between protein and tannin level was observed for WG, FC, or PW in all experiments. Neither protein nor tannin level had an effect on PW expressed as a percentage of body weight. In all experiments, feeding the suboptimal protein level significantly (P < .05) depressed WG and FC of turkeys compared with the diet that was adequate in protein. Increasing tannin level linearly depressed WG and increased FC in Experiments 1 and 2. However, tannin level did not affect WG or FC of turkeys 8 to 12 wk of age (Experiment 3). It is possible that the presumably more fully developed digestive processes of 8-wk-old turkeys were able to overcome the antinutritional effects of tannins. Results of the present study suggest that if high tannin grains are to be utilized in turkey diets, they should be fed to birds older than 8 wk.