Influence of Feed Additive Supplementation on Growth Response, Gut Health, and Meat Quality of Broiler Chicken

The effects of organic acid or synbiotic and their mixture on the growth performance, gut morphology, intestinal microbiota, and meat quality of broiler chicken were investigated in a 42-day feeding trial. One hundred and forty (140) one-day-old broiler chicks were randomly allocated into 4 diets with 5 replicates of 7 birds each. Diet 1 was a basal diet (control diet). Diets 2, 3 and 4 contained the basal diet +0.1% organic acid, basal diet+0.05% synbiotic, basal diet + 0.1% organic acid + 0.05% synbiotic respectively. Performance indices were measured. On day 42, ileal digesta samples were collected from three birds per replicate for microbial counts while about 5 cm of distal ileum was severed for morphological measurements. Also, meats were sampled for microbial count, physicochemical assessment, and thiobarbituric acid reactive substances (TBARS). Data were analyzed using descriptive statistics and ANOVA at α0.05. At the starter phase, lower feed conversion ratio (1.84) was recorded in birds fed blend of organic acid + synbiotic diet. At the finisher phase, improved FCR (1.38) was observed in birds that received organic acid diet, though, similar to the FCR of birds fed synbiotic diet (1.64). Lowest Escherichia coli counts (0.57×105 CFU/mL) (P= 0.025) were recorded in birds fed the blend diet. Increased lactic acid bacteria counts (P < 0.0001) were observed in birds fed organic acid diet. Crypt depth (161.78 µm) and villus height: crypt depth ratio (4.48) of birds fed the control diet were similar to those on the other diets. Breast meat of birds fed organic acid diet (26.22%) was significantly bigger (22.93%) than the control diet. The crude protein of birds fed organic acid diet (22.96%) and synbiotic (22.87%) were similar but the blend (24.83%) was significantly (P<0.05) higher than the basal diet (21.92%). The lowest water holding capacity (64.67%) was recorded in birds fed the basal diet while highest values (70.67%) were found in the synbiotic and blend diets. TBARs of broiler chicken meat in birds fed organic acid (0.13 mgMDA/100g), synbiotic (0.12 mgMDA/100g) and the blend (0.14 mgMDA/100g) were similar but lower than the control diet (0.22 mgMDA/100g). The microbial counts of the meat show that the total Lactobacillus count of birds on synbiotic diet (0.58×104CFU/g) and the combination of synbiotic plus organic acid (0.65×104 CFU/g) were similar but significantly (P<0.05) higher than the control diet (0.34×104 CFU/g) and organic acid diet (0.20×104 CFU/g). Salmonella count was lowest in the blend (0.32×103 CFU/g) and highest in organic acid diet (0.86×103 CFU/g) In conclusion, dietary supplementation of 1g/kg organic acid singly or plus 0.5g/kg synbiotic improved the feed conversion ratio, gut health, and meat quality of broiler chicken and can conveniently replace antibiotic growth promoters in broilers nutrition.