Abstract:
Bad litter management conditions increase the incidence of contact dermatitis cases
and the emission of ammonia from the litter. Objective of this study were to determine
the effects of two dietary crude protein (CP) levels and phytase supplementation on the
incidence of contact dermatitis and litter parameters of broiler chicken. Giving a completely
randomize design in 2 x 2 factorial arrangement, 144 broiler chicks in 48 pens received
one of the four diets having two dietary CP (20 or 22%) and phytase (o, 750 FTU/kg diet),
levels. Paddy husk was the litter material. On 28th and 42nd day birds were inspected and
scored for incidence of foot pad dermatitis (FPD), hock bum damage (HBD) and breast
blisters (BB). Litter samples taken on day 42 were analyzed for moisture, dry matter, pH,
N% and ammonia emission. Dietary phytase and phytase x CP levels interaction had no
significant effect on litter quality parameters. High CP diet significantly increased the
water intake of birds. Litter N% (3.1%) and moisture contents (59.3%) and ammonia
emission rate (7.2mg/kg/h) were significantly higher (pco.os) when birds were fed 22%
than 20% dietary CP (2.4%, 57.1%, 6.5mg/kg/h, respectively). Litter N (ammonia emission
= 4.016 + 1.021 N%) and moisture levels (ammonia emission = - 7.140 + 0.2404 moisture
%) lenierly (p<0.001) increased the ammonia emission rate. Irrespective of phytase
supplementation, incidences of FPD, BB and HBD were significantly higher among the
birds fed 22% dietary CP. The incidences of FPD, HB and BB on day 42 were significantly
higher than on day 28. It is concluded that use of higher dietary CP levels in broiler diefs
increase the litter ammonia emission rate and the incidence of contact dermatitis cases.
