Effect of feeding diets based on coarse maize on productive performance, gizzard development and energy utilisation...

1. A total of 2200 White Leghorn layers were used to study the effect of feeding coarse maize on productive performance, gizzard weight, apparent metabolisable energy (AME) and egg quality parameters. 2. The experiment was a completely randomised design with 5 treatments, each being replicated 5 times (88 birds per replicate). Dietary treatments included a control diet with 600 g/kg of ground maize (6 mm sieve) and experimental diets with 150, 300, 450 or 600 g/kg coarse maize (10 mm sieve) replacing (w/w) ground maize. Diets, in mash form, were offered from 39 to 62 weeks of age. 3. Over the entire experimental period, dietary treatments had no effect on any of the production parameters, except on feed intake. A quadratic effect was observed for feed intake, where intake increased at 150 g/kg coarse maize inclusion. At higher inclusion levels of coarse maize, feed intake was similar to that of the control diet. But the differences in daily intake between dietary treatments were only around 1 g/bird and may not be of any biological significance. 4. Dietary treatments had no effect on gizzard weight, AME or egg quality. 5. The results indicate that coarse maize could completely replace maize in layer diets with no adverse effect on egg production, egg quality and dietary energy utilisation. In the current work, although the proportion of coarse particles (over 1 mm) increased with increasing inclusion levels of coarse maize, the differences in the percentage of particles above 1 mm between the fine control (0 g/kg coarse maize) and coarsest (600 g/kg coarse maize) diets was only 15%, and this may limit the value of the findings reported herein.