Use of whole wheat, along with compounded feeds, for poultry feeding is a common practice in many parts of the world. However, studies investigating the use of other grains are limited. In the present study, the influence of including whole maize, with differing hardness, in broiler diets on the performance, nutrient utilisation and digestive tract development was examined. The experimental design was a 3 × 2 factorial arrangement of treatments, evaluating maize hardness (hard, semi-hard or soft) with diets based on ground maize or 115 g/kg whole maize replacing ground maize. The three maize cultivars were ground in a hammer mill to pass through a 4 mm sieve and six diets were developed based on one of the three cultivars. Following mixing, all diets were cold pelleted through a 3 mm die. Each of the six diets was fed to six replicate cages (eight birds per cage) from day 1 to 21 post-hatch. Maize hardness and whole maize inclusion had no effect (P>0.05) on weight gain. Maize hardness influenced (P<0.05) feed intake and feed per gain, while these two parameters were unaffected (P>0.05) by the inclusion of whole maize. The apparent metabolisable energy (AME) was unaffected (P>0.05) by maize hardness and whole maize inclusion. Maize hardness increased the ileal digestibility of nitrogen (P<0.05) and starch (P=0.06). The relative weight of the gizzard was greater (P<0.05) in birds fed hard and semi-hard maize compared to soft maize, and was greater (P<0.05) when whole maize was included. These results indicated that 115 g/kg of ground maize can be replaced by whole maize in broiler starter diets with no adverse effects on growth performance and thus can reduce the cost of feed manufacture.

Experimental comparisons of the nutritional value of different wheat cultivars commonly use feeds in meal form even though the large-scale broiler producers use steam pelleted feeds. The aim of this experiment was to examine the effect of steam pelleting on the performance, dietary N-corrected apparent metabolisable energy (AMEn), total tract dry matter retention (DMR), nitrogen retention (NR) and fat digestibility (FD) coefficients, and digestive tract development of broilers fed four different wheat samples in complete diets. Four European wheat samples, with different chemical composition and endosperm characteristics, were used in a broiler experiment. The wheat samples were milled through a 5 mm screen and four basal feeds containing 670 g/kg of each selected wheat sample were mixed. The basal feeds were then split into two batches and one of them was steam pelleted resulting in eight experimental diets. Each diet was fed ad libitum to eight pens of two male Ross 308 broilers from 10 to 24 days of age. Feeding pelleted diets improved (P<0.001) feed intake and weight gain, and daily water intake of the birds. Pelleting also improved dietary AMEn and FD (P<0.001) and DMR (P<0.05). An interaction (P<0.05) was observed between wheat samples and steam pelleting for NR. Steam pelleting improved (P<0.05) NR in the wheat sample with high starch and protein and hard endosperm but not in the rest of the wheat samples. Similar interactions (P<0.05) were also observed between wheat sample and steam pelleting for gain to feed (G : F) and water to feed (W : F) ratios. Pelleting improved G : F ratio the greatest in the wheat sample with high starch and protein and hard endosperm. Feeding the same wheat sample also decreased (P<0.05) W : F but only in the mash diets. Regardless of the wheat sample the values of dietary AMEn did not differ (P>0.05). Feeding different wheat types and pelleting did not (P>0.05) change the development of the gastrointestinal tract of the birds. The study showed that there were differences between four wheat samples when they were fed in pelleted complete feed, but no differences were observed when fed in mash form complete diets. Research on the interaction between pelleting and wheat chemical and quality characteristics is warranted.