The Combination of Different Dietary Fiber Sources Improves the Growth Performance, Nutrient Digestibility and Intestinal Function in Broilers from 1 to 42 d of Age

This experiment was conducted to investigate the effects of combinations of different dietary fiber sources (inulin and cellulose) on broilers from 1 to 42 d of age. A total of 560 Arbor Acres male broilers were randomly divided into seven dietary treatments with eight replicates per treatment and 10 broilers per replicate. A con-soybean control (CON) diet, CON diet supplemented with antibiotics (zinc bacitracin, 50 mg/kg, AB diet), CON diet diluted with 2% of inulin (LNU), CON diet diluted with 1.5% of inulin and 0.5% of cellulose (MIX1), CON diet diluted with 1.0% of inulin and 1.0% of cellulose (MIX2), CON diet diluted with 0.5% of inulin and 1.5% of cellulose (MIX3), and CON diet diluted with 2.0% of cellulose (CEL). Results demonstrated body weight (BW) (d42) and average daily gain (ADG) (d1 to 21, d22 to 42, d1 to 42) were significantly increased (p < 0.05), and the feed-to-gain ratio (F/G) (d1 to 21, d22 to 42, d1 to 42) was markedly decreased (p < 0.01) in the MIX1 group than those in the other treatments. Compared to broilers fed CON, AB, or other diets, broilers fed with the MIX1 diet had markedly improved (p < 0.05) nutrients utilization, lactase and superoxide dismutase (SOD) activities, and mRNA expression levels of jejunal function-related genes (SGLT1, GLUT2, PepT1, GLP-2, and ZO-1), while significantly decreased (p < 0.05) intestinal pH, TNF-α content and IL-6 mRNA level in jejunum at 21 or 42 days of age. Collectively, dietary fiber was included in broiler diets at a total level of 2%, and the MIX1 combination (combining 1.5% of inulin and 0.5% of cellulose) promoted growth performance, nutrient digestibility, and intestinal function, and this diet may be a potential alternative to antibiotics.