Effect of different growth promoters on broiler performance and gut morphology

A total of 240 Hybro broilers was divided into 4 groups. These groups were fed a complete corn/soybean based diet with and without addition of antibiotic growth promoters (AGP, Flavomycin (R) 15 ppm, Intervet), direct feed microbials (DFM, All-Lac (R) 1kg/T Alltech Inc. USA) and mannanoligosaccharide (MOS) (Bio-MOS (R) 2kg/T. Alltech Inc. USA). Chickens were introduced into the experiment after hatching. At day 42 of trial, all broilers were conventionaly sacrificed in a slaughter plant and slaughter performances were measured. Samples of intestines with its content from 6 average broilers (randomly selected) from each group (n=24) were taken for examination. At the end of the trial, body weight (BW) and body weight gain (BWG) of broilers fed the diet containing Bio-MOS (R) (1915.23 and 44.58 g), AGP (1869.40 and 43.50 g) and DFMI (1855.50 and 43.17g) were significantly higher than in birds of the control group (1815.67 and 41.96 g). When compared with the control group (91.19 g), ADFI (average daily feed intake) was also significantly reduced when Bio-MOS (R) (81.84 g), DFM (83.50g) or AGP (86.16 g) were supplemented which lead to a lower feed conversion ratio (FCR), 2.17 vs. 1.83, 1.93 and 1.98 kg, respectively. A significantly lower pH of the intestinal content of intestines (duodenum, ileum, caecum) was observed in groups fed DFM (6.16, 6.46 and 6.72) and Bio-MOS (R) (6.25, 6.50 and 6.78), compared with the control (6.55, 6.81 and 7.21) and AGP (6.61, 6.87 and 7.14) group. The use of DFM and Bio-MOS (R) increased length and width of intestinal villa and decreased depth of crypts, while the number of goblet cells did not significantly differ among experimental groups. In conclusion, Bio-MOS (R) and DFM exhibited nutritional, pharmacological and economic advantages over antibiotic growth promoters.