J. Zelenka et E. Fajmonova, Calcium, magnesium and phosphorus retention in chickens with different growth rate fattened to higher age, CZEC J ANIM, 46(3), 2001, pp. 118-121
Utilisation of calcium, magnesium and phosphorus was examined in broilers a
nd laying type cockerels from Day 23 to Day 100. In meat type chickens coef
ficients of apparent Ca and P retention decreased highly significantly (P <
0.01) during the whole experiment while that of Mg decreased till the age
of 93 days. In egg type chickens the dependence of Ca retention on age was
expressed by the parabola of the 2nd degree with a minimum on Day 70. Utili
sation of Mg and P decreased linearly and highly significantly. Content of
Ca and Mg in body gains of broilers increased (P < 0.01) with age. Concentr
ation of P culminated on Day 45. In laying type chickens the level of Mg in
creased highly significantly and that of P decreased (P < 0.01). The Ca con
tent in body gains decreased tin Day 43; thereafter, an increase was record
ed. Differences in average coefficients of Ca and P retention and retention
per unit of body gain in slow growing hybrid and broiler chickens were not
significant (P > 0.05) while retention of Mg was highly significantly high
er in laying type chickens.