Effect of phytase supplementation on phosphorus utilization and performance in layer chicken

Abstract

The effect of three levels of phytase enzyme viz., 200, 300 and 400 units per kg in the low available phosphorus layer ration on phosphorus utilization and performance in egg type chicken was evaluated using one hundred and fifty White Leghorn strain cross pullets (ATHUL YA) of 21 weeks of age for a period of 20 weeks. The birds were divided into five dietary treatment groups viz., standard layer ration (T1), low available phosphorus layer ration (T2), low available phosphorus layer ration with 200, 300 and 400 units of phytase per kg feed (T3, T 4 and T5), respectively. Standard layer ration was formulated as per BIS specification for layer chicken. Initially, the ration with 0.3 per cent available phosphorus was formulated. By the addition of appropriate levels of dicalcium phosphate to this ration, diets with 0.5 per cent available phosphorus was formulated. A numerical improvement in per cent hen-day egg production was noticed among enzyme supplemented groups. However, the increase was not statistically significant. Daily feed intake per bird was significantly higher among birds fed with different levels of enzyme in low available phosphorus layer ration. Phytase supplementation did not have significant influence upon feed per dozen eggs. Body weight gain was not influenced by enzyme supplementation. Significantly higher egg weight was obtained for the groups fed low available phosphorus diets supplemented with varying levels of phytase. Phytase addition to low available phosphorus diets significantly improved egg specific gravity.

Supplementation of phytase resulted in significant increase in egg shell weight. Mean shell thickness was significantly more among enzyme supplemented groups. Serum calcium levels of the enzyme supplemented groups registered significantly (p < 0.01) higher values whereas only numerical improvement could be noticed in serum inorganic phosphorus levels. Per cent tibial ash and phosphorus content were not influenced by phytase supplementation. Enzyme supplementation resulted In a numerical improvement In the bio-availability of calcium. Bio-availability of phosphorus was significantly more among enzyme supplemented groups as well as standard layer mash fed birds. Phosphorus excretion in the droppings (g/kg DM intake) was significantly (p < 0.01) reduced in the enzyme supplemented groups. The per cent survivability of laying hens was not affected by phytase inclusion. Cost of the feed per kg was lower in all the enzyme supplemented groups than the standard layer ration of this study. Based on the findings, it can be concluded that by the inclusion of 200 units per kg of phytase enzyme in layer diet, the available phosphorus level in the feed can be reduced to 0.3 per cent without affecting the over all performance. This also facilitates to reduce phosphorus excretion which is an eco-friendly factor in commercial layer operations.