Superdosis de fitasa en cerdos desde inicio hasta finalización, considerando diferentes niveles de liberación de calcio y fósforo

Phosphorus (P) is a finite resource, and its inefficient use in swine production contributes to environmental P losses; therefore, nutritional strategies that improve P utilization without compromising performance are needed. This study evaluated the effects of superdosing phytase under different calcium (Ca) and P matrix crediting schemes on growth performance, apparent total tract digestibility (ATTD) of P, and economic feasibility of pigs under commercial conditions. A total of 900 pigs (initial body weight 25.53 ± 1.95 kg) were allotted to 20 pens (45 pigs/pen; 5 replicates/treatment) and fed corn–soybean meal diets for 70 days in three phases (starter, grower, and finisher). Treatments were: 1000 FTU/kg (control), 1500 FTU/kg, 2000:1500 FTU/kg (500 FTU/kg on top), and 2000:1000 FTU/kg (1000 FTU/kg on top). Average daily gain, average daily feed intake, and feed conversion ratio did not differ among treatments (P > 0.05), although a dose × age interaction tended to occur for gain and intake (P = 0.08), with numerical improvements during the finishing phase for 2000:1000 and 2000:1500. Treatments credited at 1500 FTU/kg (1500 and 2000:1500) increased ATTD of P (P = 0.006) and ash (P = 0.0001) compared with 2000:1000; the control was intermediate for ATTD of P. Feed cost per kg of weight gain was not affected (P = 0.11), but a dose × age interaction tended to be present (P = 0.06), with differences of up to $0.23/kg during finishing. In conclusion, superdosing phytase up to 2000 FTU/kg was performance-neutral, and crediting 1500 FTU/kg for Ca and P improved P utilization, which may support its adoption to optimize P use and reduce P excretion.