Sub-acute Dietary Exposure to Tyre-Flame Processed Cow Hide (Ponmo) Increases Serum Lead and Copper Levels in Male Wistar Rats Without Significant Changes in Liver Enzymes: A Preliminary Toxicology Study

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@article{1718764,
      author = {Nwawuba, N. I., Ijeh, I. I., Ekeleme, C. M.},
      title = {Sub-acute Dietary Exposure to Tyre-Flame Processed Cow Hide (Ponmo) Increases Serum Lead and Copper Levels in Male Wistar Rats Without Significant Changes in Liver Enzymes: A Preliminary Toxicology Study},
      journal = {Iconic Research And Engineering Journals},
      year = {2026},
      volume = {9},
      number = {12},
      pages = {1408-1415},
      issn = {2456-8880},
      url = {https://www.irejournals.com/formatedpaper/1718764.pdf},
      abstract = {Background: Cow hide (Ponmo) is a widely consumed animal by product in West Africa. Singeing using scrap tyre flames may introduce toxic heavy metals into the product. However, limited in vivo toxicological data exist on the biological effects of consuming tyre flame processed (TFP) cow hide.
Objective: This preliminary study evaluated sub acute (28 day) dietary exposure to TFP cow hide on serum heavy metal concentrations and liver function markers in male Wistar rats.
Methods: Twenty five male Wistar rats (5–6 weeks, 100–144 g) were randomly assigned to five groups (n=5 per group). Groups 1–3 received 10%, 20%, and 30% TFP cow hide in diet; Group 4 received 20% razor shaved processed (RSP) cow hide (method control); Group 5 received normal rat chow (negative control). After 28 days, serum heavy metals (Pb, Cd, Cu, Zn, As, Ni) were analyzed by atomic absorption spectroscopy, and aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) by spectrophotometry. Due to the preliminary nature of this study, histopathological examination was not performed, and liver enzyme data alone cannot definitively rule out subclinical hepatotoxicity.
Results: Rats fed 30% TFP cow hide showed the highest serum lead concentration (1.30±0.01 mg/L) compared to the RSP control (0.02±0.01 mg/L; p < 0.05). Copper levels were higher in the 20% TFP (0.22±0.01 mg/L) and 30% TFP (0.12±0.01 mg/L) groups compared to the normal control (0.06±0.02 mg/L; p < 0.05). Nickel was elevated in the 30% TFP group (1.23±0.01 mg/L). Notably, the normal control group showed unexpectedly high arsenic levels (0.72±0.02 mg/L), suggesting possible baseline contamination of the rat chow. No statistically significant differences (p > 0.05) in AST, ALT, or ALP activities were observed between any groups. However, in the absence of histopathological examination, subclinical liver injury cannot be excluded.
Conclusion: In this preliminary sub acute study (28 days, n=5 per group), consumption of TFP cow hide was associated with elevated serum lead and copper concentrations in male Wistar rats. Serum liver enzyme markers showed no significant differences between treatment and control groups. However, histopathological examination is required to definitively assess hepatotoxicity. These findings are hypothesis generating rather than confirmatory. Chronic toxicity studies with larger sample sizes (n ≥ 10), histopathological evaluation, analysis of multiple batches of TFP cow hide, and quantification of heavy metals in the feed itself are necessary before concluding that tyre flamed Ponmo poses a human health hazard.},
      keywords = {Ponmo; Cow Hide, Heavy Metals, Lead, Sub-Acute Toxicity, Wistar Rats, Tyre Burning, Preliminary Study},
      month = {June},
      doi = {https://doi.org/10.64388/IREV9I12-1718764}
  }