MVSc

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.