67955
document
Effect of dietary zinc oxide on jejunal morphological and immunological characteristics in weaned piglets . The aim of this study was to evaluate age-related changes and the effect of dietary Zn concentration on morphological and immunological characteristics in the gastrointestinal tract of piglets . A total of 96 purebred Landrace piglets were weaned at the age of 26 ± 1 d , and randomly allocated into 3 treatment groups fed with low ( 57 mg Zn/kg ) , medium ( 164 mg Zn/kg ) , and high ( 2425 mg Zn/kg ) dietary Zn ( ZnO ) . Piglets ( 4 males and 4 females per treatment group ) were killed at 33 ± 1 , 40 ± 1 , 47 ± 1 , and 54 ± 1 d of age . In the jejunum , villus height , crypt depth , and the number of goblet cells producing neutral , acidic , sulfated , and sialylated mucins were measured . Intraepithelial lymphocytes were characterized by flow cytometry and the gene expression of mucin 2 ( MUC2 ) , mucin 20 ( MUC20 ) , β-defensin 3 , and trefoil factor 3 ( TFF3 ) was determined by reverse transcription quantitative PCR . Villus height and crypt depth in the jejunum showed age related differences ( P < 0.01 ) , whereas the dietary concentrations of Zn had no effect . The mucin types were modified mainly by age , and dietary Zn had no effect in the proximal jejunum . In the distal jejunum , age and Zn had effects on the mucin types . The abundance of sulfomucins decreased ( P < 0.001 ) and sialomucins increased with age ( P < 0.001 ) , while high dietary ZnO reduced the sulfomucins ( P < 0.001 ) and increased the sialomucins ( P < 0.05 ) in the crypts . The phenotypes of lymphocytes in the epithelium of the proximal jejunum showed relatively constant percentages of T-cells , as well as natural killer cells . High dietary Zn treatment led to a reduced abundance of CD8 ( + ) γδ T-cells ( P < 0.05 ) . The apportionment of different cytotoxic T-cell was age dependent . Although the percentage of CD4 ( - ) CD8β ( + ) increased ( P < 0.01 ) , the relative amount of CD4 ( + ) CD8β ( + ) decreased with age ( P < 0.05 ) . The expression of MUC2 and MUC20 was not influenced by age or dietary Zn concentration . High Zn intakes resulted in a reduced gene expression of β-defensin 3 ( P < 0.05 ) , but did not affect the expression of TFF3 . It is concluded that Zn in the form of ZnO appears to have specific effects on the innate and adaptive gut associated immune system of piglets . These might contribute to the positive effects of Zn on the prevention of postweaning diarrhea .
67956
Intervention_Pharmacological
dietary zinc oxide
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Outcome_Physical
abundance of sulfomucins
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Outcome_Physical
0.001 ) and sialomucins
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Outcome_Physical
constant percentages of T-cells
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Outcome_Physical
cells
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Outcome_Physical
High dietary Zn treatment
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Outcome_Physical
abundance of CD8 ( + ) γδ
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Outcome_Physical
different cytotoxic
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Outcome_Physical
percentage of CD4 ( - ) CD8β ( + )
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Outcome_Physical
0.01 ) , the relative amount of CD4 ( + ) CD8β ( + )
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Outcome_Physical
expression of β-defensin
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Participant_Condition
weaned piglets .
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Participant_Sample-size
96
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Participant_Age
age of 26 ± 1 d
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Participant_Sample-size
4
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Participant_Sex
males
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Participant_Sample-size
4
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Participant_Sex
females