Effects of high-tannin sorghum and bentonite on the performance of laying hens.

The effects of feeding high-tannin sorghum (HTS) (5% catechin equivalents (CE)) on the performance of laying hens were examined in two experiments. In experiment 1, the effects of including varying levels of HTS in layer diets were investigated. Sixty-three Isabrown hens were randomly assigned to each of the seven diets over a period of 56 days. In experiment 2, the effects of bentonite on the utilization of HTS (3.74% CE) by laying hens were investigated. Forty-five Isabrown hens were randomly assigned to each of five diets over a period of 42 days. In both experiments, weekly measurements were made for feed intake (FI), percent hen-house production (% HHP), egg weight and egg specific gravity (ESG). The results of experiment 1 showed that the different sorghum inclusion levels had no effect (p > 0.05) on HHP, egg weight and ESG, while those of experiment 2 showed that maize and LTS diets gave similar weight gain. FI and FE (p > 0.05). However, HHP was higher (p < 0.05) for the LTS diet than for the other diets. The addition of bentonite of 0.25% or 0.5% to the HTS diet did not improve (p > 0.05) layer performance. When all the results were considered together, it was concluded that HTS can be used in layer diets without adverse effects on performance. The use of bentonite to deactivate sorghum tannins is not considered necessary.