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. unpro cessed barley in the diet (400 g kg(-1)) on the response of broiler ch ickens 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 0 00 U g(-1)). The four experimental diets were as follows: B, unprocess ed barley; BE, unprocessed barley + enzyme (200 mg kg(-1)); ExB, extru ded barley; ExBE, extruded barley + enzyme (200 mg kg(-1)). The diets were fed as pellets. Extruded compared with unextruded barley gave hig her soluble fibre (28 vs. 36 g kg(-1)) and lower insoluble (190 vs. 16 3 g kg(-1)) and total (219 vs. 200 g kg(-1)) dietary fibre values. Ext rusion 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 f irst week, birds fed extruded barley in the diet increased water consu mption (P less than or equal to 0.05), A significant depression in fee d 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 extru ded 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 uti lisation (-0.5 vs. 5.6%; P = 0.12), as well as beta-glucan degradabili ty (10.4 vs. 15.6%; P = 0.41). In general, the enzyme had more impact on chick performance than barley form.