The capacity of a novel consensus bacterial 6-phytase variant (PhyG) to entirely replace dietary inorganic phosphorus (Pi) source in grower pigs fed diets with reduction of calcium (Ca), net energy (NE) and digestible amino acids (AA) was evaluated, using growth performance and apparent total tract digestibility (ATTD) of nutrients as outcome measures. A total of 352 mixed-sex pigs (initial BW 23.4 kg) were randomized to 4 treatments, 8 pigs/pen and 11 pens/treatment. Diets were corn-soybean meal-based and formulated by phase (grower 1, 25 to 50 and grower 2, 50 to 75 kg BW). The positive control diet (PC) provided adequate nutrients and a negative control diet (NC) was formulated without Pi (1.2 g/kg ATTD P) and reduced in Ca (-0.12 to -0.13 percentage points), NE (-32 kcal/kg) and digestible essential AA (-0.004 to -0.026 percentage points) vs. PC. Two further treatments comprised the NC plus 500 or 1,000 FTU/kg of PhyG. Data were analyzed by ANOVA, mean contrasts and orthogonal polynomial regression. Nutrient reductions in the NC reduced (P < 0.05) average daily gain (ADG) during grower 1 and overall (73 to 136 days of age), increased (P < 0.05) feed conversion ratio (FCR) during grower 1 and overall and tended to reduce (P < 0.1) average daily feed intake (ADFI) during grower 2 and overall, vs. PC. Phytase supplementation improved (P < 0.05) FCR during grower 1, ADG during grower 2 and overall, ATTD of DM and P, and tended to improve DE (P = 0.053) in a linear dose-dependent manner. PhyG at 1,000 FTU/kg resulted in growth performance (all measures, all phases) equivalent to PC. The findings demonstrate that PhyG at 1,000 FTU/kg totally replaced Pi in complex grower pig diets containing industrial co-products, compensated a full nutrient matrix reduction and maintained performance.

This work aimed to compare piglet’s performance when fed DL-Methionine or Hydroxy-Methionine (OH-Met and OH-MetCa) at the requirements of sulfur amino acids (SAA) or above. 720 piglets (♀ large white*landrace x ♂ pietrain*duroc) were weaned at 28 days old (6.84 ± 1.07 kg) and randomly allocated to the experimental treatments for 42 days. The experiment was a factorial design with three Met sources (DL-Met, liquid OH-Met (acid form) or OH-MetCa under powder form) and two doses of SAA. Treatments were formulated to reach the adequate SID SAA/Lys ratio of 58% or exceeded the Spanish nutrient recommendations in SAA by 25% (0.79% SID SAA/Lys). Each treatment was replicated 12 times (6 pens of males and 6 pens of females). Growth performance was measured and data was analysed by mixed-effects models (R Core Team). The body weight was neither affected by SAA level, nor by the Met sources. The daily weight gain (DWG) was not affected by the dietary treatments from 0 to 21 days; whereas the feed conversion ratio (FCR) was significantly (P=0.01) improved when the SAA level was increased by 25% (1.272 and 1.184) due to the decreased feed intake (P=0.03). Significant interactions were found between the Sex and the SAA level for DWG (P = 0.04) and FCR (P = 0.03) from 0 to 21 days. From day 21 to 42 and from day 0 to 42, no performance criteria were different in all dietary treatments. For all criteria of performance, the three Met sources exhibited a similar response. These results confirmed that Met sources are equivalent in piglets.