DIETARY MANIPULATIONS FOR IMPROVING PRODUCTION RATE, PERSISTENCY AND EGG QUALITY IN SINGLE COMB WHITE LEGHORN (LOHMANN) LAYERS

Abstract

The study used 90 two-and-a-half-year-old Single Comb (S.C.) White Leghorn (Lohmann) strain already at laying with a rate of 32.55%. The feeding experiment compared the effects of dietary protein (18, 20 and 22%) and added methionine (0.00, 0.15 and 0.30%) on the performance of culled layers over a 12-week period. All treatments with three replications were arranged in a 3 x 3 factorial experiment in a completely randomized design with an inclusion of a reference diet in the treatments.

Results showed significantly lower feed intake in 22% CP treated rations and no differences in methionine level. Average weekly production rate was higher at 18% and the interaction effect of CP and methionine levels. Feed

conversion efficiency (FCE) was higher among the layers fed with 18% CP, while the lowest FCE was at 22% CP in the diet. Significantly better egg production was at 0.15% methionine. Interaction effect revealed significantly higher egg production at 18% CP and 0.30% methionine level. Culling rate was higher at 22% CP and 0.30% methionine. Mortality showed higher among the layers fed with 18% CP and no differences in methionine levels.

Egg weights increased with increasing protein levels and reference diets have significantly lighter eggs. Heaviest eggs were obtained at 22% CP and 0.30% methionine. Egg mass equivalent (EME) was significantly better in layers fed with 18% CP while at 22% CP had, however, lower EME and at 0.30% methionine. Thinner egg shells were observed among layers fed with 22% CP and 0.30% methionine.

Feed cost per doze egg produced was significantly higher in birtds fed 22% CP diet while the lower feed cost was in birds fed with 18% CP. Income over feed cost was positively higher at 18% and negatively higher at 22% CP, while the interaction effects showed positively higher at 22% CP and 0.30% methionine and negatively lowest was obtained at 22% CP and 0.15% methionine.