EFFECT OF 2-ROW OR 6-ROW BARLEY AND A COMMERCIAL ENZYME PREPARATION ON GROWING-FINISHING BROILER-CHICKENS FROM 3-WEEKS TO 6-WEEKS OF AGE

A study was conducted to determine the efficacy of barley-based diets with or without a crude enzyme preparation for male broiler chickens f rom 3 to 6 wk of age. Treatments consisted of feeding grower and finis her diets based on two locally grown cultivars of barley, 2-row (unspe cified cultivar) and 6-row (Leger) added at 0, 20, 40 and 60%, with 0 or 1000 mg commercial enzyme preparation/kg diet. The starter diet con tained no barley. Enzyme addition to the 2-row barley-based diets resu lted in significantly heavier 6 wk body weights compared to the non-su pplemented diets and significantly improved feed efficiencies during t he 5- to 6-wk period indicating an enzyme response in older birds. Lev el of 2-row barley did not have significant main effects on 6 wk body weight, weight gain, feed consumption, feed efficiency, mortality, or live grade, except for leg abnormalities. A significant linear contras t revealed increased percentage of leg abnormalities as the level of b arley in the diet increased. Significant interactions were found betwe en level of 2-row barley and enzyme addition for feed consumption and feed efficiency from 3 to 5 wk of age. Significant quadratic contrasts for level of barley within non-supplemented treatments indicated lowe r feed consumption of the 20 and 40% barley-fed birds than the 0 and 6 0% barley-fed birds during the 3-to 5-wk period. During the 5- to 6-wk period, feed consumption of the enzyme-supplemented diets increased l inearly with percentage of barley in the ration. Neither level of 6-ro w barley nor enzyme addition to the 6-row barley diets had significant main effects on 6 wk body weight, weight gain, feed consumption, feed efficiency, or live grade. Significant interactions were found betwee n level of 6-row barley and enzyme addition for 6 wk body weight, 3-6 wk weight gain and feed consumption for the 5-6 wk period. A significa nt quadratic contrast for level of barley within non-supplemented trea tments revealed lower feed consumption of the 20 and 40% barley-fed bi rds compared to the 0 and 60% barley-fed birds during the 5-6 wk perio d. Thus, for the diets without glucanase, there was an effect of barle y percentage which became apparent at different ages depending on the barley cultivar. As with the 2-row barley diets, there was a significa nt linear increase in feed consumption of the enzyme-supplemented diet s as the level of 6-row barley in the diet increased during the 5-6 wk period. It appears from the results that the grower and finisher diet s could contain up to 60% barley without being detrimental to growth b ut incidence of mortality or leg abnormality may increase somewhat. En zyme addition improved feed efficiency for the 2-row barley diets, and erased the quadratic effects of barley level apparent when diets did not include beta-glucanase.