Effects of Corn Particle Sizes on Growth Performance and Gastrointestinal Morphology of Broiler Chickens = تأثير أحجام حبيبات الذرة على كفاءة النمو و القياسات الشكلية للجهاز الهضمي في دجاج اللحم

Abstract

This study was conducted to determine the effect of corn particle sizes on broiler performance, carcass characteristics and intestinal morphology during growing stage. Forty five broiler chickens were brooded for 21 days and thereafter divided into three treatment groups. Each group were fed different level of corn particle sizes (fine = 0.96 mm, medium = 1.22 mm and coarse = 1.60 mm). Each treatment was replicated five times (3 birds/replicate). The experiment was conducted from day 21 to day 42 of age (week 4 - week 6). At d 42, all birds were slaughtered and eviscerated for carcass and intestinal moropholgy analysis. The results showed that corn particle size level did not affect average daily gain (ADG) (g/day) at the end of week 4 (range from 73.57-75.18 g/day ), week 5 (range from 77.39-81.9 g/day) and week 6 (range from 68.57-72.65 g/day); feed conversion ratio (g/g) at the end of week 4 (range from 1.53-1.55), week 5 (range from 1.62-1.87) and week 6 (range from 2.16-2.32); cumulative feed intake (g) at the end of week 4 (range from 796-808 g ) week 5 (range from 1007-1050 g) and week 6 (range from 1085.8-1159.0g). In addition, no effect was pronounced on dressing percentage yield (range from 73.9-75.1%) and gastrointestinal relative organ weight and gastrointestinal relative length and weight with exception for small intestine. Broilers fed medium corn particle sizes (i.e 1.22 mm) had a lower relative weight and relative length weight (2.49 g/kg of BW and 24.99 cm/kg of BW, respectively) compared to broiler fed fine particle sizes (0.94 mm) (2.71 g/kg of BW and 27.13 cm/kg of BW, respectively) and coarse particle sizes (1.6 mm) (2.78 g/kg of BW and 27.82 cm/kg of BW, respectively). It can be concluded that coarse milling of corn grains above the recommended particle sizes have no influence on overall growth parameters in broiler chicken during grower stage. However, subsequent processing steps (such as mixing and pelleting) may be compromised and should be investigated when incorporating coarse particles sizes in poultry diets.