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High dietary zinc supplementation increases the occurrence of tetracycline and sulfonamide resistance genes in the intestine of weaned pigs.

Vahjen W, Pietruszyńska D, Starke IC, Zentek J - Gut Pathog (2015)

Bottom Line: Overall, the combined data (n = 336) showed that copy numbers for tetracycline and sulfonamide resistance genes were significantly increased in the high zinc treatment compared to the low (tetA: p value < 10(-6); sul1: p value = 1 × 10(-5)) or intermediate (tetA: P < 1.6 × 10(-4); sul1: P = 3.2 × 10(-4)) zinc treatment.Regarding the time dependent development, no treatment effects were seen 1 week after weaning, but significant differences between high and low/intermediate zinc treatments evolved 2 weeks after weaning.The increased number of tetA and sul1 copies was not confined to the hind gut, but was already present in stomach contents.

View Article: PubMed Central - PubMed

Affiliation: Institute of Animal Nutrition, Freie Universität Berlin, Berlin, Germany.

ABSTRACT

Background: Dietary zinc oxide is used in pig nutrition to combat post weaning diarrhoea. Recent data suggests that high doses (2.5 g/kg feed) increase the bacterial antibiotic resistance development in weaned pigs. Therefore, the aim of this study was to investigate the development of enterobacterial antibiotic resistance genes in the intestinal tract of weaned pigs.

Findings: Weaned pigs were fed diets for 4 weeks containing 57 (low), 164 (intermediate) or 2425 (high) mg kg(-1) analytical grade ZnO. DNA extracts from stomach, mid-jejunum, terminal ileum and colon ascendens were amplified by qPCR assays to quantify copy numbers for the tetracycline (tetA) and sulfonamide (sul1) resistance genes in Gram-negative bacteria. Overall, the combined data (n = 336) showed that copy numbers for tetracycline and sulfonamide resistance genes were significantly increased in the high zinc treatment compared to the low (tetA: p value < 10(-6); sul1: p value = 1 × 10(-5)) or intermediate (tetA: P < 1.6 × 10(-4); sul1: P = 3.2 × 10(-4)) zinc treatment. Regarding the time dependent development, no treatment effects were seen 1 week after weaning, but significant differences between high and low/intermediate zinc treatments evolved 2 weeks after weaning. The increased number of tetA and sul1 copies was not confined to the hind gut, but was already present in stomach contents.

Conclusions: The results of this study suggest that the use of high doses of dietary zinc beyond 2 weeks after weaning should be avoided in pigs due to the possible increase of antibiotic resistance in Gram-negative bacteria.

No MeSH data available.


Related in: MedlinePlus

Distribution of antibiotic resistance in the intestine of pigs. Combined data from all sampling days; open bar low dietary Zn; barwith diagonal lines intermediate dietary Zn; hatchedbar high dietary Zn; a,bSignificantly different; a = tetA gene; bsul1 gene
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Fig2: Distribution of antibiotic resistance in the intestine of pigs. Combined data from all sampling days; open bar low dietary Zn; barwith diagonal lines intermediate dietary Zn; hatchedbar high dietary Zn; a,bSignificantly different; a = tetA gene; bsul1 gene

Mentions: The presence of tetA and sul1 genes within the gastro-intestinal tract was also addressed in this study. An analysis for gastro-intestinal sites revealed that significant differences between low/intermediate and high treatment groups occurred already in the stomach and continued throughout the intestinal tract (Fig. 2). The lowest copy numbers for each group were found in the small intestine. Pigs harbor a very metabolically active gastric microbiota during the first weeks after weaning, due to a comparably high pH in the stomach. Enterobacteria and even strict anaerobic bacterial groups can be found via molecular methods in the stomach and small intestine [2, 24]. A hypothesis put forward by our research group [3, 14] states that zinc ions are released already in the stomach, thereby modifying the microbiota that reaches the small and large intestine, because zinc oxide displays increased solubility at acidic pH. Indeed, the ratio of free zinc ions to total zinc is highest in the stomach, followed by reduced ratios in the small intestine, while only very low concentrations of free zinc are observed in the large intestine [25]. Thus, high concentrations of dietary zinc may have the strongest impact in the stomach, generating zinc resistant enterobacteria which then “inoculate” the small and large intestine.Fig. 2


High dietary zinc supplementation increases the occurrence of tetracycline and sulfonamide resistance genes in the intestine of weaned pigs.

Vahjen W, Pietruszyńska D, Starke IC, Zentek J - Gut Pathog (2015)

Distribution of antibiotic resistance in the intestine of pigs. Combined data from all sampling days; open bar low dietary Zn; barwith diagonal lines intermediate dietary Zn; hatchedbar high dietary Zn; a,bSignificantly different; a = tetA gene; bsul1 gene
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4551370&req=5

Fig2: Distribution of antibiotic resistance in the intestine of pigs. Combined data from all sampling days; open bar low dietary Zn; barwith diagonal lines intermediate dietary Zn; hatchedbar high dietary Zn; a,bSignificantly different; a = tetA gene; bsul1 gene
Mentions: The presence of tetA and sul1 genes within the gastro-intestinal tract was also addressed in this study. An analysis for gastro-intestinal sites revealed that significant differences between low/intermediate and high treatment groups occurred already in the stomach and continued throughout the intestinal tract (Fig. 2). The lowest copy numbers for each group were found in the small intestine. Pigs harbor a very metabolically active gastric microbiota during the first weeks after weaning, due to a comparably high pH in the stomach. Enterobacteria and even strict anaerobic bacterial groups can be found via molecular methods in the stomach and small intestine [2, 24]. A hypothesis put forward by our research group [3, 14] states that zinc ions are released already in the stomach, thereby modifying the microbiota that reaches the small and large intestine, because zinc oxide displays increased solubility at acidic pH. Indeed, the ratio of free zinc ions to total zinc is highest in the stomach, followed by reduced ratios in the small intestine, while only very low concentrations of free zinc are observed in the large intestine [25]. Thus, high concentrations of dietary zinc may have the strongest impact in the stomach, generating zinc resistant enterobacteria which then “inoculate” the small and large intestine.Fig. 2

Bottom Line: Overall, the combined data (n = 336) showed that copy numbers for tetracycline and sulfonamide resistance genes were significantly increased in the high zinc treatment compared to the low (tetA: p value < 10(-6); sul1: p value = 1 × 10(-5)) or intermediate (tetA: P < 1.6 × 10(-4); sul1: P = 3.2 × 10(-4)) zinc treatment.Regarding the time dependent development, no treatment effects were seen 1 week after weaning, but significant differences between high and low/intermediate zinc treatments evolved 2 weeks after weaning.The increased number of tetA and sul1 copies was not confined to the hind gut, but was already present in stomach contents.

View Article: PubMed Central - PubMed

Affiliation: Institute of Animal Nutrition, Freie Universität Berlin, Berlin, Germany.

ABSTRACT

Background: Dietary zinc oxide is used in pig nutrition to combat post weaning diarrhoea. Recent data suggests that high doses (2.5 g/kg feed) increase the bacterial antibiotic resistance development in weaned pigs. Therefore, the aim of this study was to investigate the development of enterobacterial antibiotic resistance genes in the intestinal tract of weaned pigs.

Findings: Weaned pigs were fed diets for 4 weeks containing 57 (low), 164 (intermediate) or 2425 (high) mg kg(-1) analytical grade ZnO. DNA extracts from stomach, mid-jejunum, terminal ileum and colon ascendens were amplified by qPCR assays to quantify copy numbers for the tetracycline (tetA) and sulfonamide (sul1) resistance genes in Gram-negative bacteria. Overall, the combined data (n = 336) showed that copy numbers for tetracycline and sulfonamide resistance genes were significantly increased in the high zinc treatment compared to the low (tetA: p value < 10(-6); sul1: p value = 1 × 10(-5)) or intermediate (tetA: P < 1.6 × 10(-4); sul1: P = 3.2 × 10(-4)) zinc treatment. Regarding the time dependent development, no treatment effects were seen 1 week after weaning, but significant differences between high and low/intermediate zinc treatments evolved 2 weeks after weaning. The increased number of tetA and sul1 copies was not confined to the hind gut, but was already present in stomach contents.

Conclusions: The results of this study suggest that the use of high doses of dietary zinc beyond 2 weeks after weaning should be avoided in pigs due to the possible increase of antibiotic resistance in Gram-negative bacteria.

No MeSH data available.


Related in: MedlinePlus