EFFECT OF QUALITATIVE FEED RESTRICTION ON PULLET DEVELOPMENT AND SUBSEQUENT EGG PRODUCTION.

Abstract

The effect of feeding different protein levels  during the rearing and development of egg-type  pullets as well as on eventual egg production was investigated in two experiments. In experiment I, the dietary crude protein (CP) regimens (and old to point of lay notations) in isocaloric diets for the periods 0-8 weeks and 9-20 weeks respectively for treatment 1: 20% and 16% (20:16), treatment 2: 16% and 16% (16:16), treatment 3: 12% and 12% (12:12), treatment 4: 16% and 12% (16:12), treatment 5:20% and 12% (20:12) and for treatment 6 theregimens comprised 20% for 0-8 weeks, 16% for9-16 weeks and 12% for 17-20 weeks (20:16:12) In experiment 2, treatments 1 to 5 for experiments 1 were repeated while three step-up dietary treatments 6, 7 and 8 were evaluated in addition. For the periods 0-8 weeks and 9-20 weeks respectively, the CP regimens for treatment 6 were 12% and 16% (12:20) and for traetment 7, 12% and 20% (12:20) and for treatment 8, 16% and 20% (16:20). From 20 weeks in each experiment, a common layer diet containing 16% CP and 2,449 Kcals metabolizable energy per kg was fed ad libitum to all treatments and all the subsequent egg production was monitored for a further 16 weeks . Both studies indicated that production was reported egg-type chickens fed diets with a drastic protein restriction (12%) in the starting period (0-8 weeks) had significantly reduced body weights at 20 weeks and delayed sexual maturity.  However, when such birds were subsequently (9-20 weeks) offered diets with higher protein content significant compensatory effects on weight gain and feed conversion were indicated. The step-up CP règimens in experiment 2 performed.