Effect of reduction of dietary protein level, associated with an adjusted electrolytic balance or not, on performance of lactating sows exposed to 23 or 26°C on average

The effect of dietary crude protein (CP) level, associated with a reduced electrolytic balance (EB) or not, was tested on 52 crossbred Large White x Landrace sows exposed to 23 (n=20) or 26 (n=32)°C on average. The CP content and EB of the control diet (PBE) were 16.5% and 176 mEq/kg, respectively. In low CP diets (14.4%), the EB value was 141 mEq/kg for treatment pbe and adjusted to 176 mEq/kg for treatment pBE, formulated with sodium bicarbonate. Lysine, methionine, threonine and tryptophan levels were similar for all diets. Sows were fed ad libitum from the 6th post-farrowing day until weaning. Reduced CP level did not influence significantly daily feed intake (6.33 kg/d for PBE and pbe, on average) or other components of lactation performance, which resulted in a 10% reduction of calculated nitrogen output. Lactation performance of pBE sows were not improved; average litter growth tended to be lower (2.91, 2.89 et 2.79 kg/d for PBE, pbe et pBE sows, respectively, P