Izvorni znanstveni članak
Performance and bone quality of laying hens fed low- phosphorus diets based on different cereal grains and supplemented with phytase
Dorota Jamroz
J. Orda
Jolanta Skorupińska
T. Wertelecki
A. Wiliczkiewicz
R. Żyłka
J. Brož
Sažetak
The purpose of the present study was to evaluate the response of laying hens to the low-phosphorus diets based on different kinds of cereal grains and supplemented with microbial phytase. Laying performance, feed intake, egg shell quality as well as bone strength parameters and Ca, P, Mg and Zn contents in the bones were involved as experimental parameters. At the age of 17 weeks, 288 Lohmann Brown pullets were assigned to the six dietary treatments, each treatment consisting of 12 cages with 4 birds per one. Until the beginning of the laying period the pullets were fed a standard diet containing 145 g of crude protein and 11.3 MJ ME, 4 g non-phytate P and 10.6 g of Ca per kg feed. The experimental diets provided from the first day of laying were based on maize (diets I, II, III) or on a combination of maize, barley and wheat (diets IV, V, VI) and contained about 165 g CP and 11.2 MJ ME/kg. In diets I, III or IV and VI the level of non-phytate phosphorus was decreased to 1.41 g/kg while in control diets (III or V) the amount of non-phytate P was 3.0 g/kg. In low-P diets III and VI microbial 6-phytase was included at the level of 450 FTU/kg diet.
The phosphorus level in diets did not affect the laying rate during the experimental period of 53 weeks. The higher P-level in feed enhanced egg shell strength only (P<0.01). Supplementation of low-P-diets with phytase did not affect the performance of hens, such as feed intake and egg quality, however it improved the egg shell strength as compared to low-P unsupplemented groups. Regarding strength and elasticity of the tibia, the P-level and phytase supplement were without visible effects. The best parameters that characterize the bone quality were obtained by addition of 3 g of non-phytate P level per kg of diets.
Ključne riječi
laying hens; microbial phytase; performance; egg shell quality; bone quality
Hrčak ID:
3630
URI
Datum izdavanja:
7.3.2006.
Posjeta: 2.058 *