EFFICACY OF PHYTASE SUPPLEMENTATION TO LOW PHOSPHORUS AND LYSINE BROILER CHICKENS DIET ON PERFORMANCE, BLOOD PARAMETERS AND NUTRIENTS DIGESTIBILITY
Asmaa S. El-Far*, H.A. Ahmed, Mervat A. Abdel- Latif and M. A. Emam
To assess the effects of the dietary phytase on the growth performance, and apparent nutrient digestibility of broiler chickens fed low available phosphorus and lysine diets, a total of 240 one-day-old Cobb 500 chicks were randomly allocated into six groups, with four replicates (40 birds/ group). The chicks were fed the starter (first two weeks), grower (second two weeks) and finisher (last week) diets supplemented with 0 or 1000 FTU/kg phytase activity. Six mash diets were formulated for the experimental groups which consisting of group 1 (control group, G1) fed corn soybean based diet without phytase supplementation. group 2 (G2) fed on lower NPP by 0.1% than required; group 3 fed (G3) on diet with 0.05% lower lysine than required; 4th , 5th and 6th group (G4, G5 and G6) fed on the same diets of the previous groups respectively, but supplemented with phytase enzyme at a level of 0.2 g/kg diet. All birds received control diet during the first week and fed the experimental diet from the second week till the end of the experimental period. The highest BW was for the group fed the basal diet supplemented with phytase (the on top) that had increased feed consumption (1.6%; P ≤ 0.05) with similar FCR and PER to the control. Addition of phytase to low NPP diet (G4) non significantly increased FBW and TWG, but showed significant (P ≤ 0.05) decrease in TFI and FCR with higher PER and economic efficiency (P ≤ 0.05) comparing with the group fed low NPP without phytase. The birds of G5 and G6 had higher CP digestibility than those of G2 and G3 respectively. Moreover, significant (P ≤ 0.05) improvements in lysine digestibility (7.2%) and phosphorus (P) availability were observed with phytase supplementation. Further that, phytase supplementation had no adverse effect on haematological indices and biochemical constituents of serum, liver and kidney functions. It was concluded that phytase supplementation achieved better growth performance and higher economic efficiency. In addition, dietary phytase supplementation could replace 0.1% available phosphorous and 0.05% lysine.
Keywords: Broilers, Microbial phytase, performance, P availability, lysine digestibility.
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