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Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
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[A simple indicator for ruling out inadequate phosphorus digestibility in growing pigs]
Linda Böswald1, Ellen Kienzle1
1Lehrstuhl für Tierernährung und Diätetik, Ludwig-Maximilians-Universität München.
Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere
|August 22, 2019
Summary
Faecal calcium/phosphorus ratios can indicate phosphorus digestibility in growing pigs. Ratios above specific thresholds suggest high phosphorus digestibility, simplifying diagnosis of potential deficiencies.
Area of Science:
- Animal Nutrition
- Mineral Metabolism
- Swine Production
Background:
- Species-specific calcium and phosphorus metabolism influences dietary requirements.
- Faecal calcium/phosphorus (Ca/P) ratios offer insights into mineral metabolism.
- Phosphorus deficiency can impact growing pigs, necessitating accurate diagnostic tools.
Purpose of the Study:
- To evaluate faecal Ca/P ratios as a simple diagnostic tool for phosphorus digestibility in growing pigs.
- To establish thresholds for faecal Ca/P ratios indicative of adequate phosphorus utilization.
- To aid in diagnosing suspected phosphorus deficiency when dietary calcium and phosphorus levels are adequate.
Main Methods:
- A meta-analysis of 34 studies involving phytase-supplemented and control diets.
- Analysis of dietary intake and faecal excretion of calcium and phosphorus.
- Application of a modified Lucas-test to plot mineral intake against faecal excretion.
Main Results:
- No significant difference in calcium excretion between supplemented and control groups.
- Significantly lower relative faecal phosphorus excretion in phytase-supplemented diets.
- Faecal Ca/P ratios were categorized by pig body weight and apparent phosphorus digestibility.
Conclusions:
- Faecal Ca/P ratios above 1.5 (pigs ≤ 30 kg) and 1.2 (pigs > 30 kg) indicate high apparent phosphorus digestibility (>60% and >40%, respectively) with adequate dietary Ca/P (>1.2).
- High faecal Ca/P ratios suggest phosphorus digestibility is unlikely to be low.
- Faecal Ca/P ratios below thresholds do not allow definitive conclusions on phosphorus digestibility.
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