Intoxication of sheep with quebracho tannin extract

Area of Science:

• Animal Science
• Toxicology
• Ruminant Nutrition

Background:

• Condensed tannins (CTs) are plant polyphenols with potential applications in animal feed.
• Quebracho tannin extract, rich in CTs, is being evaluated as a feed additive.
• Understanding the toxicity of tannin extracts is crucial for safe application in livestock.

Purpose of the Study:

• To assess the toxicity of quebracho tannin extract in sheep.
• To validate its potential use as a feed additive for improving protein utilization.
• To determine safe dosage levels for ruminant livestock.

Main Methods:

• Four groups of sheep were administered varying intra-ruminal doses of quebracho tannin extract (0, 0.5, 1.5, 3.0 g/kg LW) daily for 21 days.
• Evaluated parameters included feed intake, live-weight changes, plasma biochemistry, hepatic function indicators, gross lesions, and histopathology.
• High-dose animals (3.0 g/kg LW) were humanely euthanized due to severe adverse effects.

Main Results:

• Sheep receiving 0, 0.5, or 1.5 g/kg LW of extract maintained normal feed intake and health.
• The highest dose (3.0 g/kg LW) resulted in drastically reduced feed intake, significant weight loss, weakness, and recumbency.
• High-dose sheep exhibited severe digestive tract lesions (ulcers, distension) and reduced cytochrome P-450 and glutathione levels.

Conclusions:

• Quebracho tannin extract is not toxic to ruminants at doses relevant to practical feed additive applications.
• Excessively high concentrations of quebracho tannin extract can induce significant toxicity and pathological changes in sheep.
• The findings support the potential use of quebracho tannin extract as a feed additive within established safe limits.