Effects Of Citric Acid On Growth, Immune, Digestive Tract And Blood Indexes In Broilers

In the present study, two tests (high-dose test and low-dose test) were conducted to explore the effects of citric acid (CA) on the indexes of growth, immune, digestive tract and blood of broilers. Single-factor randomized test design was used in the two tests. In the high-dose test, a total of 180 one-day-old healthy AA broilers were selected and randomly allotted into three treatments, each treatment consisted of six replicates with ten broilers in each replicate. The three experimental diets were formulated with basal diet supplemented with 0 (control group), 0.75%, and 1.5% CA, respectively. In the low-dose test, 144 one-day-old AA broilers were choosed and randomly divided into three treatments with four replicates of 12 broilers. The three experimental diets were formulated with basal diet supplemented with 0 (control group), 0.1%, and 0.4% CA, respectively. Each of the two tests lasted 42 d, and experimental diets and water were available adlibitum during the entire experimental period. The experimental results were showed as follows:â‘ Adding CA to diets affected growth performance of broilers. ADG, ADFI and G/F of broilers were significantly lower than the control group (p <0.05); 0.4 % CA showed a better effect in low-dose test, it significantly improve the growth performance of broilers (p <0.05).â‘¡Dietary CA affected immune functions in broilers. In high-dose test, broilers fed on 1.5% CA could significantly improve the immune functions (p <0.05). In low-dose test, broilers of 0.4% CA group's immunoglobulin IgA and IgM decreased significantly, IgG significantly increased (p<0.05), and sCD8 significantly decreased (p <0.05).â‘¢Dietary CA could affect the gastrointestinal-related indicators of broilers in dose-dependent manner. In high-dose test, crop and jejuna chyme pH values could significantly decreased of the broilers in two groups, two groups can significantly improve the structure of duodenal villi (p <0.05); 0.4% citric acid diet group were more effective than other group in low dose CA test (p <0.05). In both test, Gut microbes have different degrees of improvement, no significant difference between the groups (p> 0.05).â‘£In addition, dietary CA levels could affect serum hormones in broilers. In high-dose test, IGF-I of 21 day-old broilers significantly increased ,and CORT significantly decreased (p <0.05), 42 day-old broilers ACTH significantly decreased too (p <0.05); 0.4% CA group had more obvious effect in low-dose test,(p <0.05).