Abstract:
This experiment was conducted to evaluate the ability of supplemental
microbial phytase (500 kg FTU) to improve the utilization of essential aminoacid
(lysine and methionine) that could be bound to phytate. The effect of
microbial phytase in performance, dressing percentage and protein efficiency
ratio (PER) of the broiler were investigated through the experimental period
(6 weeks).
A total of 72 one-day old, unsexed commercial chicks (ROSS 308
strain) were used in this experiment. On the 7th day of age chicks were
weighed and allotted randomly to 3 treatments (24 birds for each treatment, 4
replicates "6 chicks for each replicates") and experimentally fed for 7 weeks
on a ground brooding rearing system.
Three types of diets were used: diet (A) the positive control diet which
completed in essential amino-acid according to the requirements of the
broiler, diet (C) negative control based on plant protein which deficient in
both lysine and methionine, diet (B) similar to diet (C) but supplemented with
microbial phytase. All were formulated to be isonitorgens (23 % crud protein)
and isococaloric (3100 kcal/kg). Health of the experimental stock and
mortality were closely observed. Records of feed intakes weight gains and
feed efficiency were taken during the feeding period. Dressing percentages
were calculated after slaughtering and eviscerating. The results indicated that
the microbial phytase supplementation to broiler plant based diet deficient in
lysine and methionine caused a significant (p< 0.05) improvement in body
weight gain and hot and cold dressing percentages with increased in feed
intake. This value still significantly (p< 0.05) lower than that achieved with
positive control. Also the results included that the feed efficiency value were
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improved insignificantly (p> 0.05) by the addition of microbial phytase. But
the supplementation of phytase had beneficial effect on protein efficiency
ratio.
The economical evaluation of addition microbial phytase to plant based
diet (negative control) in this study showed an increases in net profit/kg from
1090 to 3900 sp but this values still lower than that obtained by positive
control 6640 sp.
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