Effect of feed enzymes supplementation in corn - soya and de-oiled rice bran based diet on skeletal status of broiler chickens

In an experiment, a total of 96 left tibia bone of broiler chicks (8 per treatment) were collected at the end of feeding trial (07wks) comprising 12 dietary treatments in a completely randomized design. Two basal diets (D1) and (D9) were formulated separately for each growth phases containing 0.45 and 0.35% available phosphorus(AP) for starting phase (0-3wks) and 0.35 and 0.25% (AP) for finishing phase (4-7wks). The other eleven dietary treatments includes D2 (C + multienzyme-Multi), D3 (C + xylanase-Xyl), D4 (C + Xyl + Multi), D5 (C + Phytase-phy), D6 (C + Phy + Multi), D7 (C + Phy + Xyl.), D8 (C+ Phy.+ Multi.+Xyl.), D9 (C-0.1% Av.P + phy), D10 (C-0.1% Av.P + Phy + Multi), D11 (C-0.1% Av.P + Phy + Xyl) and D12 (C-0.1%Av.P + Phy + Xyl +Multi). The supplemental rates of feed enzymes were multienzyme- 500 mg/kg, xylanase- 20mg/kg and phytase- 100 mg/kg. The osteomorphometry (length and width of tibia bone) and mineralization traits (bone moisture, dried bone weight, bone ash, bone calcium and bone phosphorus) contents were evaluated. Significantly (P<0.01) lower tibia bone length was observed in group fed D3 diet supplemented with xylanase enzyme than those observed in other dietary treatments. Significantly (P<0.01) higher proximal width of tibia bone was observed in group fed D6 (Phy.+Multi.) diet than those recorded in D1 (control), D3, D4, D7, D8 and D12. However, proximal width of tibia bone observed in groups fed D1, D2, D4, D5, D7, D9, D10 and D11 did not differ significantly from each other. Significantly (P<0.01) lower value of bone weight was observed in group fed D3 diet than those recorded in other dietary treatments including control group. The tibia bone ash (%) was significantly (P<0.05) higher in group fed D3 diet than those recorded in D1 (control), D8 and D12 diets. However, comparatively higher bone ash percentage was noticed in most of the phytase treated groups. There is scope of reducing 0.10% available phosphorus through phytase enzyme supplementation simultaneously reducing environmental pollution. Based on the results it is concluded that Supplementation of phytase + multienzyme with 0.1% less available phosphorus(D10) was found best among various combinations to improve bone growth and mineralization in broiler chickens.