| Iron is an important trace element for the organism and there are differences in the biological effects of different iron sources.Fe-molasses is a new organic trace element and it is inexpensive.The aim of this experiment was to compare the effects of Fe-molasses with Fefumarate and Fe-Gly on growth and development,iron metabolism and cecal microorganisms of piglets,and the theoretical basis for the application of iron molasses is also provided.In this experiment,32 healthy 35-day-old crossbred weaned male piglets were selected and randomly divided into 4 treatments each of which included 8 replicates of 1 pig.Pigs were reared in single cages to ensure that the difference in body weight between treatments was not significant(P > 0.05).Treatment 1 was the control and the iron source was ferrous sulphate monohydrate,while the iron sources for treatments 2,3 and 4 were Fe-fumarate,Fe-Gly and Fe-molasses,respectively.The level of iron addition was 100 mg/kg(as iron)for all treatments.Feeding trials were conducted for 7 d adaptation period and 42 d experiment period.All faeces were collected between 21-24 d of the experiment and feed intake and faecal output were recorded.At the end of the trial,all pigs were slaughtered after blood collection,and then samples of longissimus dorsi,liver,duodenum,and cecal contents were collected,and heart,liver,spleen,lung and kidney weights,and duodenum length were recorded to calculate organ indexes.The results showed that:1.Effects of different iron sources on growth performance in pigletsThe addition of different iron sources to the piglets’ diets did not increase the final body weight(P > 0.05),but the addition of molasses iron significantly improved the daily weight gain and reduced the feed-to-weight ratio compared with the control group(P < 0.05),and the Fe-molasses group had the highest daily weight gain and the lowest feed-to-weight ratio;Femolasses significantly increased the apparent digestibility of dry matter,organic matter and crude protein in piglets(P < 0.05);Fe-molasses significantly increased the spleen index,whereas Fe-Gly and Fe-molasses significantly increased the lung and duodenal index of piglets.2.Effects of different iron sources on iron metabolism in pigletsCompared with the control group,the hemoglobin content of Fe-molasses group piglets was significantly increased(P < 0.05),the erythrocyte count and hematocrit of Fe-fumarate and Fe-Gly piglets were significantly increased(P < 0.05),but there was no significant difference in the whole blood indexes of three kinds of organic iron(P > 0.05);All the three organic iron sources could reduce the total iron binding capacity(TIBC)content(P < 0.05);Fe-molasses significantly increased the biological availability of iron and the content of iron in longissimus dorsi muscle and liver of piglets(P < 0.05),Fe-Gly can increase the biological availability of iron and the content of iron in longissimus dorsi muscle of piglets(P < 0.05),iron glycine and Fe-molasses significantly reduced iron excretion in feces of piglets(P < 0.05);Fe-molasses and Fe-Gly groups significantly increased the villus height and the ratio of villus to crypto(P <0.05),significantly increased the expressions of divalent metal ion transporter(DMT1)and membrane iron transporter 1(FPN1)in duodenum(P < 0.05),significantly decreased crypt depth of duodenum(P < 0.05).3.Effects of different iron sources on cecal microorganisms in pigletsDifferent iron sources had no difference(P > 0.05)on Chao1,Shannon,Simpson,and ACE indices of cecal microorganisms.At the phylum level,Fe-molasses significantly increased P < 0.05)the relative abundance of Firmicutes in the cecum.At the genus level,Fe-molasses improves the relative abundance of Clostridium＿sensu＿stricto＿1 and Lactobacillus(P < 0.05),Fe-fumarate significantly increased the relative abundance of Roseburia in cecum(P < 0.05),the relative abundance of Roseburia in Fe-fumarate and Fe-Gly groups was significantly higher(P < 0.05)than that in Fe-molasses group.Spielman correlation analysis showed that Clostridium＿sensu＿stricto＿1 had a significant negative correlation with feed to gain ratio(P < 0.05),was significantly positively correlated with propionic acid(P < 0.05);There was a significant positive correlation between Lactobacillus and propionic acid(P < 0.05);There was a significant negative correlation between Roseburia and propionic acid(P < 0.05).4.Effects of different iron sources on serum biochemistry and antioxidants in pigletsCompared with the control group,different iron sources could decrease the activity of alanine aminotransferase and increase the activity of alkaline phosphatase(P <0.05),and Femolasses decreased serum triglyceride and urea nitrogen contents(P < 0.05),serum total protein content was significantly increased(P < 0.05)in Fe-Gly group.Different iron sources can increase the activity of superoxide dismutase(SOD)in serum and jejunum(P < 0.05),decreased the content of malondialdehyde(MDA)(P < 0.05),Fe-Gly and Fe-molasses can increase total glutathione and reduced glutathione contents in serum and jejunum(P < 0.05),respectively.Fefumarate increased the contents of total glutathione,oxidized glutathione and reduced glutathione in jejunum(P < 0.05),respectively.In conclusion,Fe-Gly and Fe-molasses can significantly improve the growth performance,absorption and utilization of nutrients,enhance the antioxidant capacity of serum and intestinal tract,improve the body iron metabolism and intestinal morphology of piglets.The intestinal microecological balance of piglets was regulated by improving the relative abundance of Clostridium＿sensu＿stricto＿1,Roseburia and Lactobacillus. |
