The Effects Of Dietary Vanadium On Small Intestinal Morphology And Intestinal Microbiota In Broilers

The objective of this study was to determine the effect of dietary vanadium on small intestinal morphology in broilers by the methods of light microscopy (LM) and transmission electron microscopy (TEM) and to examine the effects of dietary vanadium on the intestinal microorganism diversity and contents of short-chain fatty acids (SCFA; such as acetate, propionate and butyrate) in broilers by plate count, PCR-DGGE (Denaturing gradient gel electrophoresis), and gas chromatography (GC)-flame ionization detection analysis. A total of420one-day-old avian broilers were divided into six groups (seven replicates in each group and ten broilers in each replicate) and fed on control diet or the same diet supplemented with5,15,30,45and60mg/kg vanadium in the form of ammonium metavanadate. In this42-days experiment, vanadium diet in excess of30mg/kg significantly restrained (P<0.05or P<0.01) the development of small intestine by restraining the growth of villus and crypt and decreasing villus/crypt in duodenum, jejunum and ileum at14,28and42days. Vanadium diet also negatively affected the microvillus height of abovementioned three intestines in the60mg/kg group at42days. When compared with those of contol group, dietary vanadium in the range from30to60mg/kg could decrease the counts of Bifidobacterium spp. and obviously affect the colonization of those in the intestinal tract. Meanwhile, the counts of E. coli were significantly increased with the increasing concentrations of vanadium except in duodenum. However, the changes of Lactobacillus counts varied along the intestinal tract. DGGE analysis showed that band numbers of duodenum, ileum, cecum and rectum were decreased in the30,45and60mg/kg groups at21and42days of age. In addition, the similarity index in the abovementioned intestines is higher between the30mg/kg group and the60mg/kg group than that between the control group and5mg/kg group at21and42days of age. The acetate contents at21days of age and propionate contents at42days of age were decreased (P<0.05) in the60mg/kg group in comparison with those of the control group. In conclusion, dietary vanadium affected the villus height, crypt depth, villus/crypt and the growth of microvillus, which could impact the development of duodenum, jejunum and ileum in broilers. At the same time, dietary vanadium also affected the amount and diversity of intestinal microbiota in the duodenal, ileac, cecal and rectal digesta, implying that the initial balance in the intestine was definitely disrupted by dietary vanadium.