| Five experiments for this thesis were conducted to find out a method analyzing complexed Mn in buffer solutions quantitatively, and investigate the differences of the absorption of manganese between organic and inorganic manganese in the small intestines of broilers by the methods of everted intestinal sacs, ligated and perfused intestinal segments and practicalfeeding.Experiment I Study on complexed Mn percentages in organic manganese sourcesStructural characteristics of manganese glycine chelate (Mn-Gly) was determined by infrared spectroscopy. The percentages of complexed Mn in Mn-Gly and manganese methionine chelate (Mn-Met) were determined in 0.1 M Tris buffer (pH7) by gel filtration chromatography and cation exchanging equilibrium. The results showed that: 1) Mn-Gly chelate had characteristic peaks of complexed Mn; 2) Under the experimental condition mentioned above, no complexed Mn was found for Mn-Gly and Mn-Met chelates in pH7, 0.1M Tris buffer solutions. The results suggest that the reason why complexed Mn was not found in the solutions was possibly the complexed Mn dissociated during the processes of gel filtration and cation exchanging, because of the weak binding energy of Mn and the ligands. It can not be concluded that no complexed manganese exist in the solutions of Mn-Gly and Mn-Met according to the results. In addition, the results of this study did not show the situations in vivo, so more studies should be focused on the conditions of the intestine of the animals to investigate the absorption characteristic of organic manganese.Experiment II In vitro study on absorption of manganese as different manganese sources by everted gut sacs of broilersTwo in vitro experiments were conducted to investigate the absorption differences between organic and inorganic manganese by incubating everted intestinal sacs of broilers in media containing Mn as different manganese sources. Trial 1 was conducted to determine an optimum incubation time for trial 2, according to the change of manganese absorption when incubation time varied. Trial 2 was conducted to compare the absorption of organic manganese with that of inorganic manganese in the intestines of the animals with the optimum incubation time. The incubation time of four treatments in trial 1 was 20, 40, 60 and 80 min, respectively. 48 male broilers at the age of 28 day-old were randomly assigned to one of the four treatments for six replicates of two birds each. In each replicate, the intestinal sacs of one bird were incubated in media without adding manganese to it to deduct the endogenous manganese, while the intestinal sacs of the other incubated in media containing 120 Hg Mn ml-1 as MnSO4 7H2O. The duodenum,jejunum and ileum of each animal were used as one replicate of the everted sacs of corresponding intestinal segments. In trial 2, there were eight treatments of different manganese sources, which were MnSO4 7H2O, Mn-Gly chelate, Mn-Met chelate, manganese methionine complex with the weak complex strength (Mn-Met E, Qf 3.2, Mn 8.27%), manganese amino acid complex with the moderate complex strength (Mn-AA A, Qf 45.3, Mn 6.48%), manganese amino acid complex with the strong complex strength (Mn-AA B, Qf 115.4, Mn 7.86%), the mixture of MnSO4 and glycine, the mixture of MnSO4 and methionine. Mn-Met E, Mn-AA A and Mn-AA B were three organic manganese sources which had been used in our previous study of bioavailabilities of different forms of manganese. An additional group without adding manganese to the media was set up to deduct the endogenous manganese. In the treatment groups of different manganese sources, 120ug Mn ml-1 was added to the media. The incubation time of all the everted sacs was 30 min. 72 male broilers at the age of 28 day-old were randomly allotted to one of the nine treatments for eight replicates of one chick each. The duodenum, jejunum and ileum of each bird were used as one replicate of the everted sacs of corresponding intestinal segments. The results showed that: 1) The relationship between Mn absorpt... |
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