| Popis: |
SUMMARY: This study investigated the effects of fulvic acid (FA) on the growth performance, intestinal function, and fecal ammonia excretion of broilers. A total of 480 1-day-old male broilers were randomly divided into 4 treatments: control (CON) treatment, and the treatment on a basal diet supplemented with 0.15, 0.3, or 0.5% FA. The addition of 0.5% FA increased the feed-to-gain ratio and average daily feed intake during the first 7 d of the experiment, whereas, 0.3% FA addition increased the feed-to-gain ratio at 15 to 21 d, but FA addition had no effect on growth performance at other times. Compared to the CON treatment, 0.5% FA addition increased the serum IgA content, amylase, and lipase activities in the jejunum, as well as the lipase activity and mucin 2 content in the ileum. Feeding broilers with 0.15% FA increased the occludin and zonula occluden-1 content in the ileum, elevated intestinal permeability markers such as diamine oxidase, lipopolysaccharide, and D-lactate dehydrogenase, and further enriched functional pathways including nitrogen metabolism and riboflavin metabolism. Also, FA addition (0.15, 0.3, or 0.5%) increased the jejunum mucin 2 content and maintained the relative stability of the cecal microbiota without detrimental changes to the microbiota composition. Importantly, FA addition decreased the fecal ammonia yield on 2, 4, and 5 d of the fecal ammonia determination in a dose-dependent manner and also lowered the urease activity on 1 and 3 d. Therefore, the addition of 0.15% FA was considered the most effective in maintaining the intestinal health and microbial composition of broilers. |
