Investigate The Effect Of Galacto-Oligosaccharide Supplementation On Intestinal Absorption Of Iron In Rats

Objective:The present study aimed to investigate the effects of different concentrations of Galacto-oligosaccharide(GOS)on intestinal absorption of iron in rats,via the hemoglobin contents of rats,the distributions of tissue iron,the expression of iron-related proteins and the change of gut microbiota.The possible mechanisms underlying the effects of GOS on intestinal absorption of iron could provide new insights for prevention of iron deficiency anemia(IDA)using prebiotics.Methods:Sixty five SPF-grade 3-week SD rats,weighing 53.59±6.31 g,were randomly divided into low-iron model group(n=55)and the normal diet group(n=10),with low-iron rat chow(Fe?8 mg/kg)and standard AIN-93G tar chow(Fe = 35 mg/kg)being fed respectively.After the low-iron model group successfully established,rats in the model group were randomly divided into 0%GOS group,3%GOS group,5%GOS group,10%GOS group,and 10%FOS group(n=11 for each group)respectively based on hemoglobin and body weight;10%FOS group was established as positive control group.Subsequently,6 groups of rats were given different kinds of interventions.During the period,feces were carefully collected and recorded daily.Blood samples were collected for hemoglobin analysis weekly.After 3 weeks of intervention,3 rats in each group were sacrificed via perfusions and liver samples were obtained for iron content analysis.The rest of the rats were sacrificed via blood drawn and the blood samples,liver and intestinal tissue samples were collected.The haematological index was analyzed via automatic biochemical analyzer;the expression of iron-related protein in liver and intestinal tissues were analyzed via Western Blot(WB);Microbiota in cecum content was analyzed via 16S rRNA.Results:1.After modeling,the average hemoglobin contents of rats in low-iron model group was 78.69±8.01 g/L.After intervention of different concentrations of GOS,hemoglobin increased gradually.After 3 weeks,compared to 0%GOS,the hemoglobin of 5%and 10%GOS grroups increased significantly(p<0.01).Body weight of rats also decreased during the modeling period,and increased to the normal group with no statistical difference intervention period.2.There was no significant difference in liver weights between the groups.The cecal weight increased by the rise of GOS concentration with significant statistical difference,and the 0%GOS and normal group were the lowest(p<0.01).The weight of the cecal contents and the cecal wall also increased with the increasing concentration of GOS.3.There was no significant difference in serum iron between the groups.The liver iron content of 0%GOS and 3%GOS group was significantly lower than the other 4 groups(p<0.01).The storage iron content of 5%GOS and 10%GOS group were highest,followed by the 3%GOS group,and the 0%GOS and normal groups were the lowest.The serum ferritin of the 0%GOS group was lowest,and the serum hepcidin of normal group was the highest,which was statistically different with the other groups.4.WB results showed that the expression of transferrin receptor(TfR)of the 10%FOS and normal groups in the liver were higher compared with the 0%GOS group;the expression of the metalloid transporter 1(DMT1)of the 10%GOS group in the duodenum was higher compared with the normal group.The expression of ferroportin(FPN)and cytochrome b high-iron reductase(Dcytb)in the duodenum,cecum,and colon were not differentiated.5.The structure of gut microbiota in each group was significantly different(p<0.01).The community structure of the normal and the 0%GOS group were closer,and meanwhile the community structure of the 10%GOS and the 10%FOS group were closer.The addition of GOS increased the components of probiotic,but reduced the abundance:at the genus level,the components of Lactobacillus and Bifidobacterium were increased with increasing concentration of GOS.Conclusion:Supplementation of a certain amount of GOS can promote the intestinal absorption of iron in rats,the mechanism of which may be related to the difference expression of iron-related protein and gut microbiota.The 5%GOS and 10%GOS group can significantly improve intestinal absorption and utilization of iron without any difference.