MVSc

An investigation was carried out utilizing 216 commercial
day-old broiler chicks to evaluate the influence of
supplementation of phytase enzyme on phosphorus utilization and



subsequent performance.


The birds were divided into six



dietary treatment groups viz., standard broiler ration (T1) I
broiler ration with 0.3 per cent available phosphorus (AP)
(T2) I broiler ration with 0.4 per cent AP (T3) I standard
broiler ration with 750 units of phytase per kg of feed (T4) I
broiler ration with 0.3 per cent AP supplemented with 750 units
of phytase per kg of feed (T5) and broiler ration ,with 0.4 per
cent AP supplemented with 750 units of phytase per kg of feed
(T6). Standard broiler ration was formulated as per BIS (1992)
)
specifications. Initially, the ration with 0.3 per cent AP was
formulated. By the addition of appropriate levels of dicalcium
phosphate to this ration, diets with 0.4 and 0.5 per cent AP
were formulated. The groups fed standard broiler starter and
finisher rations with and without phytase and those fed rations
containing an AP of 0.4 per cent supplemented with phytase had
significantly (P<0. 01) higher body weights and body weight gain



than other treatments.


All enzyme supplemented treatments



consumed significantly (P<0.0l) more feed (g/bird/day) than
their respective unsupplemented groups except in the group
offered 0.4 per cent AP. Significantly (P<0.01) superior feed
efficiency was recorded in groups fed a diet having 0.4 per
cent AP supplemented with 750 units of phytase per kg of feed.


Phytase supplementation had a positive effect on tibial ash.
Serum calcium and inorganic phosphorus (mg per cent) were
significantly (P<0.0l) higher in enzYme supplemented groups
than their respective counterparts at sixth week of age but
were not influenced at eighth week of age. Bioavailability of
calcium and phosphorus was significantly (P<0. 01) more in



enzyme


supplemented


groups


than


their


corresponding



unsupplemented groups. Phosphorus excretion in the droppings
I'
(g/kg DM intake) was significantly (P<0. 01) reduced in enzyme



supplemented groups.


The per cent dressed yield and



ready-to-cook yield were significantly (P<0. 01) higher in
groups fed a diet having 0.4 per cent AP supplemented with



phytase than other groups.


The per cent giblet yield was



significantly (P<0. 01) more in group fed a standard diet



supplemented with phytase than other groups.


The per cent



livability was better with enzyme supplemented groups. The
cost of production per kg live weight (when feed cost alone was
considered) was cheaper in groups fed with 0.4 per cent AP
supplemented with phytase. The net profit per kg live weight
was 13 paise higher in groups maintained on 0.4 per cent AP
supplemented with phytase compared to standard broiler ration.
Based on the above findings it can be concluded that by
the addition of 750 units of phytase per kg of diet I the
available phosphorus level in broiler rations can be reduced by
0,1 per cent without affecting the overall performance.