Effects of Feed Particle Size and Feed Form on Growth Performance, Nutrient Metabolizability and Intestinal Morphology in Broiler Chickens

This study was conducted to investigate the effect of feed particle size and feed form on growth performance, nutrient metabolizability and intestinal morphology in broiler chickens. This experiment was a 2x2 factorial arrangement including two feed particle sizes (fine and coarse) and two feed forms (mash and pellet). A total of 288 day-old male Arbor Acre broilers were used in this six-week experiment. Birds were randomly allotted to four dietary treatments with six replicates per treatment and twelve birds per replicate. The results showed that pelleting of diets resulted in greater ADG (p<0.01), greater ADFI (p<0.01) and lower feed to gain ratio (F/G) (p<0.05) during starter, grower and overall periods. Also, pelleting improved both apparent metabolizable energy (AME) (p<0.01) and the apparent metabolizability of crude protein (p<0.05) and organic matter (p<0.05), regardless of the phase. Reduction of feed particle size enhanced AME (p<0.05) during d 19 to 21. Increased villus height (p<0.05) and crypt depth ratio (p<0.05) within the duodenum, jejunum, and ileum were observed in birds fed the pellet diet compared with those given the mash. In conclusion, the results indicated that feed pellets might enhance performance by improving nutrient metabolizability and digestive tract development.