CHICK PERFORMANCE AS AFFECTED BY AUTOCLAVE TREATMENT OF TANNIN-CONTAINING AND TANNIN-FREE CULTIVARS OF FABABEANS

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Abstract
Two experiments were conducted to determine the influence of condensed tannin and autoclave treatment of fababeans on nutrient utilizatiaon by chicks. In the first experiment broiler chicks were fed a series of diets containing five different cultivars of raw or autoclaved fababeans. Three of the cultivars (Triple White, Kodrim and Fidrim) were tannin-free and two (Diana and Hertz-Freya) were tannin-containing. The retention of nutrients in all cases was greater for the birds fed the tannin-free as compared to those fed the tannin-containing cultivars or for those fed the autoclaved as compared to those fed the raw fababeans. The respective retention values for birds fed tannin-containing and tannin-free raw fababeans were 42.3 and 47.9% for dry matter and 73.2 and 83.7% for total amino acids. The corresponding retention values for birds fed raw versus autoclaved fababeans that were free of condensed tannins were 47.9 and 58.7% for dry matter and 83.7 and 90.7% for total amino acids, respectively. The results of these studies suggest that autoclave treatment of fababeans affects fababean utilization by destruction of condensed tannins which accounts for approximately one-half of the total growth depression and by an effect on some other component in fababeans. The second experiment was designed to compare nutrient utilization in chicks fed diets that contained five levels of condensed tannins that had been isolated from fababean testae. The respective correlation coefficients (r) between percent condensed tannins added to the diet and chick performance were: −0.70 for feed intake, −0.90 for weight gain, +0.97 for feed:gain ratio, −0.98 for dry matter retention, −0.99 for protein retention, +0.96 for fat retention, −0.81 for ash retention and −0.72 for calcium retention. It may be concluded that the elimination of condensed tannins from fababeans by genetic selection would significantly improve its nutritional value.