Oduho G.W, Baker D.H.
Abstract
Red or brown high tannin sorghum (HTS) cultivars form the predominant cereal grain grown in Kenya around the
shores of Lake Victoria. A study was conducted to evaluate the feeding value of the HTS grain cultivars to broiler
chickens. Analysis of tannin levels in these sorghums gave a concentration in the range of 3.22 to 7.40 % Catechin
Equivalent (CE) and a mean of 4.52 % CE as compared to Low tannin sorghums (LTS) which had a range of 1.26 to
3.44 % CE and a mean of 2.78 % CE. Chicks on a 62 % HTS diet (3.70 % CE) showed a significant (P<0.05)
reduction in feed intake of 10.5% and a reduced weight gain of 14.6 % compared to those on a 62 % LTS diets (0.63
% CE). An attempt to use three LTS diets with graded levels (0,0.05, 0.10 %) of tannic acid to create a standard
curve as a biological assay to estimate the concentration of sorghum tannins was unsuccessful. The HTS and
Medium Tannin Sorghum (MTS) produced performance values that fell beyond the curves. This indicated that the
biological forms of tannins in sorghum are not identical to tannic acid in their effects in the chick. A tannin binder
polyvinylpyrrolidone (PVP) gave significantly (P<0.05) better weight gains when added to the HTS diets at 0.05 %
than at 0.25 %. The addition of intact protein from sunflower and fishmeal to HTS diets supplemented with
crystalline lysine (0.5 %) plus methionine (0.3 %) were effective in enhancing the utilization of HTS by broiler
chicks. Isocaloric and isonitrogenous diets of 62 % HTS (3.05 % CE) gave broiler chick performance that was
equal to that of chicks on a 62 % maize diet (0.6 % CE).
Key words:
Sorghum, tannin, PVP binder, broiler chicks.