The effects of phytase supplementation on performance and phosphorus excretion from broiler chickens fed low phosphorus-containing diets based on normal or low-phytic acid barley

Thacker, P.A. and Haq, I. and Willing, B.P. and Leytem, A.B. (2009) The effects of phytase supplementation on performance and phosphorus excretion from broiler chickens fed low phosphorus-containing diets based on normal or low-phytic acid barley. Asian-Australasian Journal of Animal Sciences. 22(3):404-409.

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Abstract

A total of 240 day-old broiler chicks were used to study the effects of phytase on performance and phosphorus (P)
excretion from birds fed diets containing low phytate barleys formulated without inorganic P. A positive control based on Harrington
barley (HB) was formulated to meet requirements for total P. Three experimental diets, based on either HB (0.39% total P with 0.28%
phytate P) or the low phytate varieties LP 422 (0.36% total P with 0.14% phytate P) and LP 955 (0.40% total P with 0.0 I% phytate P),
were formulated to be below requirements for total P by removing all the inorganic P from the diet. The four diets were fed with and
without 1,000 FTU/kg phytase. Apparent P digestibility was significantly higher (p<0.01) for birds fed the low phytate barleys than for
birds fed HB either supplemented or un-supplemented with inorganic P. P excretion was significantly lower (p<0.01)for birds fed HB
without inorganic P than with inorganic P. P excretion was further reduced by the use of the low phytate barleys LP 422 and LP 455
(p<0.01).Phytase supplementation did not affect P excretion (p = 0.39). Body weight gain and feed intake were highest for birds fed the
HB diet with inorganic P and lowest for birds fed the HB diet without inorganic P (p<0.01). Among the three low P diets, body weight
gain and feed intake of broilers increased as the level of phytate in the barley declined (p<0.01).Phytase modestly increased body
weight gain (p = 0.08) and feed intake (p = 0.04). The overall results of this study indicate that it may be possible to reduce the amount
of inorganic P used when formulating diets with low phytate barley compared with the levels needed when formulating diets with
normal phytate barley. However, it is not possible to completely replace the inorganic P in diets containing low phytate barley without
impairing poultry performance. Feeding diets devoid of supplementary inorganic P in combination with low phytate barley resulted in a
significant reduction in P excretion by poultry.

Item Type:	Article
NWISRL Publication Number:	1304
Subjects:	Animal
Depositing User:	Users 6 not found.
Date Deposited:	30 Nov 2009 21:12
Last Modified:	17 Oct 2016 16:31
Item ID:	1327
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1327