The effect of a specific strain of yeast derived carbohydrate fractions (YCF; Actigen^®) at two different levels was investigated on broilers performance, apparent metabolizable energy, mineral retention and gut histomorphology. One hundred and eighty, day-old male broiler (Cobb) were randomly allotted to replicated (n=4; 15 birds/replicate) dietary treatments (n=3) i.e. YCF-0, YCF-0.8 and YCF-1. The YCF-0 served as control and to the others YCF was added at the rate 0.8 and 1g kg^-1 of diet, respectively. Birds were reared in cages in an open sided house and had free access to feed and water. Significantly higher feed intake (845.26±3.30g), body weight gains (653.13±4.50g) and improved FCR (1.29±0.03) were observed in group YCF-1 compared to the other dietary groups. Difference in small intestinal length was insignificant. However, goblet cells count and villus height was increased (P<0.05) in birds supplemented with the higher level of YCF. There was a increase (P<0.05) in AME (8.22%) and retention of phosphorus (10.8%) and calcium (9.7%) by birds in group YCF-1. Relative weight of bursa, thymus and spleen improved in supplemented birds. It was concluded that supplementation of carbohydrate fraction could effectively enhance production performance, gut histomorphology and nutrient utilization by birds during starter phase.

Key words: Actigen^®, Apparent metabolizable energy, Broiler, Gut histomorphology