THE INFLUENCE OF EXTRUDED VS UNTREATED BARLEY IN THE FEED, WITH AND WITHOUT DIETARY ENZYME SUPPLEMENT ON BROILER PERFORMANCE

The experiment was conducted to study the effect of extruded vs. unprocessed barley in the diet (400 g kg(-1)) on the response of broiler chickens to Trichoderma viride enzyme supplement (cellulase, 10 500 U g(-1); endo-beta-(1:3)(1:4)-glucanase; 24 000 U g(-1) and xylanase, 32 000 U g(-1)). The four experimental diets were as follows: B, unprocessed barley; BE, unprocessed barley + enzyme (200 mg kg(-1)); ExB, extruded barley; ExBE, extruded barley + enzyme (200 mg kg(-1)). The diets were fed as pellets. Extruded compared with unextruded barley gave higher soluble fibre (28 vs. 36 g kg(-1)) and lower insoluble (190 vs. 163 g kg(-1)) and total (219 vs. 200 g kg(-1)) dietary fibre values. Extrusion increased extract viscosity (1.3 vs. 3.7 cP) and water binding capacity (1.6 vs. 2.2 ml g(-1) dry matter) of the barley. During the first week, birds fed extruded barley in the diet increased water consumption (P less than or equal to 0.05), A significant depression in feed efficiency (days 7-21), feed AME, and in fat and protein utilisation was observed when extruded barley was included in the diet. Extrusion reduced the AME content of barley by 0.82 MJ kg(-1) DM. Inclusion of extruded barley in the diet potentiated the weight gain (2.8 vs. 7.6%; P = 0.31) and feed efficiency ( + 0.8 vs. - 6%; P = 0.07) response to dietary enzyme. Greater enzyme effects with the diet containing extruded barley were also found for feed AME (1.6 vs. 2.9%; P = 0.39), fat utilisation (0.4 vs, 5.4%; P less than or equal to 0.05), nitrogen utilisation (-0.5 vs. 5.6%; P = 0.12), as well as beta-glucan degradability (10.4 vs. 15.6%; P = 0.41). In general, the enzyme had more impact on chick performance than barley form.