Effect of dietary inclusion of chitosan on growth performance and blood indices of broiler chickens

Abstract

This study evaluated the effect of dietary low-molecular-weight chitosan (LMWCHT) on the growth performance, carcass traits, cecal microbial populations, and blood indices of broiler chickens. A completely randomised design was used to assign 96 unsexed day-old Cobb 500 broiler chicks to four dietary treatment groups. Each treatment consisted of four replicate pens with six birds per pen (n = 4 pens per treatment). Following a 7-day commercial starter diet period, the birds were fed diets supplemented with LMWCHT at 0.00 (control), 0.25, 0.50, or 0.75 g/kg for a 35-day experimental period (Days 8 to 42). Growth performance metrics, averaged on a pen basis, showed that LMWCHT supplementation significantly altered average daily gain (ADG), final body weight, and average daily feed intake (P < 0.05). Broilers fed 0.50 g/kg LMWCHT exhibited the highest ADG and body weight, whereas those fed 0.75 g/kg optimised the feed conversion ratio. Cecal microbial analysis revealed that LMWCHT significantly reduced Escherichia coli counts compared to the control group (P < 0.05) without establishing a graded dose response among the inclusion levels, while lactic acid bacteria populations remained statistically unaffected (P = 0.212). Dietary LMWCHT significantly modified the haematological and serum biochemical profiles (P < 0.05), altering haemoglobin, neutrophils, monocytes, albumin, globulin, and total protein concentrations. Although the 0.50 g/kg inclusion level maintained serum alanine aminotransferase (ALT) within the standard physiological range, ALT elevations observed at 0.25 and 0.75 g/kg suggest a narrow threshold for hepatic tolerance. These results indicate that while LMWCHT alters specific performance, blood, and cecal E. coli parameters, the inclusion levels must be carefully calibrated to balance growth efficiency with systemic physiological safety.