Effect of Methionine and Choline on Tannic Acid and Tannin Toxicity in the Laying Hen

Single Comb White Leghorn hens were fed a corn-soybean meal basal diet marginal in methionine and choline to study the influence of supplemental choline and/or methionine on the toxicity of 2% tannic acid (TA) (Experiment 1) and 1% TA (Experiment 2) using 12 birds per treatment. In a third study, with two groups of 10 hens per treatment, the feeding value of a low tannin (0.26%) and two high tannin (1.20 and 1.24%) grain, sorghum varieties was studied with and without supplemental choline and methionine. In Experiment 1 the 2% TA-containing diet was toxic and caused a decrease in egg production, egg weight and body weight and an increase in egg yolk mottling. Supplementing this diet with choline, methionine or both partially alleviated the toxic effects. In Experiment 2 the 1% TA-containing diet gave a slight but non-significant reduction in egg production, decreased egg weight and body weight. In Experiment 3 the high tannin grain sorghums had no significant effects on egg production, egg weight, but there was a trend toward a decrease in both factors. The high tannin sorghums did not influence yolk mottling, but caused a reduction in body weight which was prevented by the addition of methionine and choline to the diet.