Effect of cation-anion balance in feed on urine pH in rabbits in comparison with other species.
Authors: Heer F, Dobenecker B, Kienzle E
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary Dietary cation-anion balance (CAB) significantly influences urine pH in rabbits, with controlled feeding trials demonstrating a range from 5.26 to 8.56 depending on mineral composition and ammonium chloride supplementation (CAB spanning -39 to +320 mmol/kg dry matter). Researchers fed 13 dwarf rabbits six diets of varying CAB whilst measuring urinary, faecal and blood parameters, finding that acidifying diets lowered blood pH and base excess whilst increasing renal excretion of calcium, phosphorus, sodium, magnesium and water. Interestingly, rabbits responded to acidifying diets similarly to cats, dogs and pigs, but demonstrated a tendency towards higher urine pH than other monogastric species when fed mildly alkalising diets. For equine and small animal practitioners, these findings highlight the importance of mineral ratios in formulating therapeutic or maintenance diets, particularly when managing conditions sensitive to urinary pH (such as uroliths or metabolic acidosis), and suggest that species-specific responses to dietary acidification must be considered rather than applying uniform supplementation protocols across different animals.
Read the full abstract on PubMed
Practical Takeaways
- •This study is primarily relevant to rabbit nutrition management; equine practitioners should note the comparative data on monogastric species acid-base responses may have limited application to horses
- •The research demonstrates that dietary cation-anion balance is a critical nutritional variable affecting systemic acid-base status across multiple species, including herbivores like horses
- •While focused on rabbits, the methodology and CAB calculation formula may be relevant for evaluating mineral balance effects in other species including equines
Key Findings
- •Urine pH in rabbits ranged from 5.26 at CAB of -39 mmol/kg DM to 8.56 at CAB of +320 mmol/kg DM
- •Low CAB diets significantly reduced blood pH and blood base excess in rabbits
- •Rabbits responded to acidifying diets similarly to cats, dogs and pigs
- •Rabbits on mildly alkalizing diets showed a trend toward higher urine pH compared to other monogastric species