Dietary electrolyte balance (dEB) is known to affect acid−base status and mineral metabolism, but is rarely considered in diet formulation for pigs. Yet, the use of a wide variety of local feedstuffs in Europe contributes to lowering the dEB and increasing the fibre content. Hence, mineral requirements may be modified and skeletal health affected. Therefore, the effects of a lower dEB and a higher dietary Ca level on acid−base balance and mineral status were assessed in young pigs fed a diversified diet. A total of twenty-four weaned pigs were fed a control moderate-dEB diet (C) or a diversified moderate-dEB (D), low-dEB (D-A) or low-dEB supplemented with Ca (D-CA) diet. Growth performance, venous blood gas and chemistry, urine pH, mineral balance and femur characteristics were determined. With an equivalent dEB compared with the C diet, the D diet caused an acidification of the urine and increased the excretion of P as a result of a higher dietary content of S. Low-grade metabolic acidosis occurred in piglets fed the D-A diet with changes at systemic and urine levels. A higher excretion of ammonia and P in urine was observed and some bone characteristics tended to be negatively affected. Ca supplementation partially counteracted the effects of low-grade acidosis. Urine excretion of P and ammonia was alleviated and bone characteristics improved. In conclusion, a higher Ca supply must be considered in more diversified diets to counteract the risk of evolving towards low-grade metabolic acidosis which can negatively affect bone.

Electrolytes (sodium, potassium and chloride) are compounds that dissolve intopositive and negative particles in solution. The relationship between thesecompounds, known as the ‘dietary electrolyte balance’ (DEB), is affected byeither electrolyte or its supplemental salt source. The National ResearchCouncil recommended 0.20% sodium, chloride, and 0.30% potassium for starterphase and lower doses of sodium and chloride for the finisher phase of broilers.However, these requirements are increased under heat stress conditions, andbirds perform better when increasing levels of these electrolytes are offered,maintaining a DEB of preferably 250 mEq/kg. Increased levels of theseelectrolytes, especially sodium, were found effective for growth but causedincreased water consumption and ultimately higher litter moisture in summer.Potassium and chloride were found effective in the diets of heat-stressedbroilers. Sodium bicarbonate and potassium chloride have been recognised as thebest choice in salt selection for broiler diets, particularly under hot summerconditions. In conclusion, a combination of the electrolytes with higher levelsof cations and lower level of anions is recommended. Furthermore, therequirements of these electrolytes should be explored, with reference to currentpoultry housing systems and modern genetics.