Influence of calcium and non-phytate phosphorus deficient diets with phytase on the performance of broilers, serum concentrations of minerals and the activity of alanin transaminase, aspartate transaminase and lactatedehydrogenase

An experiment was conducted to study the effect of microbial phytase (phyzymeXP5000G) supplementation in broiler chicks' diets on the performance, serum total protein(TP), minerals (Ca, Mg and P) and the serum enzyme activities (AST, ALT, LDH). A referencediet adequate in calcium and non-phytate phosphorus (10.0 gkg-1 Ca and 5 gkg-1 nPP) and twodeficient diets in Ca and nPP (8.5 gkg-1Ca and 3.5 gkg-1 nPP, and 7.5 gkg-1 Ca and 2.5 gkg-1 nPP)with or without phytase (0 and 100mgkg-1) were offered to broiler chicks from 1 to 21 days ofage. Although the low-nPP diets had no significant effect on body weight gain (BWG) of chicks(p>0.05) They increased (p<0.01) feed intake (FI) and feed conversion ratio (FCR) whencompared to the low-nPP diet supplemented with enzyme. Phytase had a favorable effect,although non-significantly, on BWG of chicks fed very low level of nPP. Enzyme reduced thefeed intake (p<0.05) and improved the FCR of Ca-nPP deficient chicks (p<0.01). The decreasein Ca-nPP content in the diet caused a significant increase in serum concentration of Ca (p< 0.05)and decrease in P concentration (p< 0.05). Low Ca-nPP diets had no influence on serum Mgconcentration. Dietary phytase reduced the Ca level and increased the P level (p<0.05) of serumin chicks fed with Ca-nPP deficient diets. The activity of LDH increased (p<0.01) in response tolow dietary Ca and nPP, deficient but there was no influence on serum ALT and AST activityand TP content (p>0.05). Phytase supplementation reduced serum ALT (p<0.05) and had noeffect on AST (p>0.05). Serum LDH activity further increased (p<0.01) by phytasesupplementation. These results demonstrated that the performance of the chicks received lowlevels of Ca and nPP with phytase was improved and the serum parameters were comparableto those chicks fed with normal Ca-nPP diet.

Keywords:

phytate phosphorus , phyzyme , broiler performance