THE EFFECT OF A WHEAT-FAT-INTERACTION ON THE EFFICACY OF A MULTIENZYME PREPARATION IN BROILER-CHICKENS

The effect of different dietary combinations of wheat (0, 250 and 500 g kg(-1)) and fat (low, medium, high) on the efficacy of a commercial multi-enzyme preparation (Bio-feed + CT: BCT) was assessed in a balanc e trial with broiler chickens from 22 to 26 days of age using mash die ts. Responses were measured in terms of excreta/feed(E/F)ratio, N-rete ntion, fat digestibility and MEn-values. All balance parameters were t o a variable degree influenced by the 3 dietary factors (wheat, fat an d BCT). In addition, there were 2 interesting interactions, (1) the fa vorable effect of BCT on the balance parameters was only obvious in co mbination with wheat (directly proportional to the wheat level) and (2 ) the effect of fat supplementation on dietary MEn-content was variabl e and dependent on dietary wheat concentration (the curvilinearity was directly proportional to the wheat level). The MEn-content of wheat w as clearly influenced by the 3 dietary factors: its inclusion level (- 3.8% lower at 500 than at 250 g kg(-1)), dietary fat level (-2 and -4% at medium and high fat level resp.) and BCT-supplementation (varying from +4.9 to 9.4%). The MEn-equivalence of BCT was quite variable, var ying from about 110 (at 0 g kg(-1) wheat) to 1020 MJ/kg (at 500 g kg(- 1) wheat combined with either medium or high dietary fat level). The r equired wheat/BCT ratio should be adapted to the dietary wheat concent ration (250 versus 500 g kg(-1)) or not. For a constant MEn-increase o f wheat (e.g. +8%) the respective ratios were 702 and 1171, but for th e same target MEn-value of wheat, this ratio was about 715 and was lar gely unaffected by dietary wheat concentration. (C) 1997 Elsevier Scie nce B.V.