Effect of Encapsulated Organic Acids on Intestinal Microbial population, Blood Parameters, Digestibility of Nutrients, Carcass characteristics and Performance of Broiler Chickens

Today, livestock and poultry health in an advanced production system is a major challenge affecting human health and the global economy. Antibiotics have been used in poultry nutrition for many years. Chickens are raised with the assistance of the regular use of antibiotics, not only for the prevention and treatment of diseases but, also, for body growth. Overuse and misuse of antibiotics in animals are contributing to the rising threat of antibiotic resistance. In recent years, as a result of increasing concerns about the possibility of developing antibiotic-resistant strains, as well as the fact that they remain in animal tissues and eventually ban their use, the use of compounds such as organic acids, probiotics, prebiotics, enzymes, etc. as safe alternatives have been widely considered in poultry nutrition. Organic acids are a good alternative to antibiotics in poultry diets. These are improving the immune system of broilers by acidifying the gastrointestinal tract and improving the intestinal microflora. Organic acids cross the bacterial membrane; inside the bacterial cell, it produces hydrogen ions and bicarbonate, which eventually increases the acidity. Therefore, they force the bacteria to consume energy in order to keep the acidity constant, which leads to their death. Coating of organic acids prevents its dissociation and digestion in the stomach so that the biological effect of organic acids reaches the distal parts of the gastrointestinal tract and is effective in intestinal microflora and mucosal morphology. This study was performed to investigate the effect of encapsulated organic acids on microbial population, intestinal acidity, blood indices, nutrient digestibility, and viscosity of digestive contents, carcass characteristics and performance of broilers. 150 male broiler chickens of Ross 308 commercial strain as one-day-old were allocated in a completely randomized design with 5 treatments, 3 replications and 10 chickens per replicate. Experimental treatments included: 1. Basal diet 2. Basal diet + commercial Organic acid 3. Basal diet + Non-encapsulated organic acid 4. Basal diet + Encapsulated organic acid 5. Basal diet + encapsulated organic acid + Non-encapsulated organic acid. On day 42 of the experiment, one chickens from each experimental unit, which were close to the weight average of that unit, were selected and blood samples were taken from their wing veins. AT 42d, from each replication, a chick with the same weight as the average weight of the experimental unit was taken and their live weight was recorded and slaughtered. Also, from each replication, a chick with a weight similar to the average weight of the experimental unit was selected and their live weight was recorded and slaughtered. Then, different parts of the carcass were weighed by peeling and emptying the viscera. In order to evaluate the microbial population of the intestines of the tested broilers, at the age of 42 days, one chick from each experimental unit was selected with conditions close to the weight average of the relevant unit and after weighing, it was slaughtered. The microbial population of Lactobacillus and gram-positive and gram-negative bacteria were studied.The data were statistically analyzed by statistical software using GLM procedure. The means were compared by Duncan method at the significance level of 0.05%. The result showed that in growth cycle, weight gain during the growth period and the whole period in the treatments containing encapsulated organic acid showed improvement and a significant difference with the control treatment. The addition of organic acids to the diet during the growth period reduced the conversion coefficient compared to the control group. Feed intake in the treatments containing capsular organic acid showed a significant decrease compare to the control group. The acidity of the duodenum and jejunum showed a significant decrease compared to the control group. The addition of encapsulated organic acids significantly reduced the total number of coliforms in the ileum and duodenum and increased the number of lactobacilli in the ileum. Also, experimental treatments increased the apparent digestibility of crude fat compared to the control group. The weight of the lymph nodes (bursa and spleen) also showed a significant increase under the influence of organic acids. The results of current experimental study showed that the usage of encapsulated organic acids in broiler chicken diets, reduces the acidity of the digestive tract, reduces the intestinal microbial contamination, creates favorable conditions in the digestive system, improves digestibility of the nutrients, and performance of the bird's growing birds.