Effect of microbial phytase on energy availability, and lipid and protein deposition in growing swine1,2

Abstract

Two experiments were conducted to determine the effect of phytase on energy availability in pigs. In Exp. 1, barrows (initial and final BW of 26 and 52 kg) were allotted to four treatments in a 2 x 2 factorial arrangement. Corn-soybean meal (C-SBM) diets were fed at two energy levels (2.9 and 3.2 x maintenance [M]) with and without the addition of 500 phytase units/kg of diet. The diets contained 115% of the requirement for Ca, available P (aP), and total lysine, and Ca and aP were decreased by 0.10% in diets with added phytase. Pigs were penned individually and fed daily at 0600 and 1700, and water was available constantly. Eight pigs were killed and ground to determine initial body composition. At the end of Exp. 1, all 48 pigs were killed for determination of carcass traits and protein and fat content by total-body electrical conductivity (TOBEC) analysis. Six pigs per treatment were ground for chemical composition. In Exp. 2, 64 barrows and gilts (initial and final BW of 23 and 47 kg) were allotted to two treatments (C-SBM with 10% defatted rice bran or that diet with reduced Ca and aP and 500 phytase units/kg of diet), with five replicate pens of barrows and three replicate pens of gilts (four pigs per pen). In Exp. 1, ADG was increased (P < 0.01) in pigs fed at 3.2 x M. Based on chemical analyses, fat deposition, kilograms of fat, retained energy (RE) in the carcass and in the carcass + viscera, fat deposition in the organs, and kilograms of protein in the carcass were increased (P < 0.10) in pigs fed the diets at 3.2 vs. 2.9 x M. Based on TOBEC analysis, fat deposition, percentage of fat increase, and RE were increased (P < 0.09) in pigs fed at 3.2 x M. Plasma urea N concentrations were increased in pigs fed at 3.2 x M with no added phytase but were not affected when phytase was added to the diet (phytase x energy, P < 0.06). Fasting plasma glucose measured on d 28, ultrasound longissimus muscle area (LMA), and 10th-rib fat depth were increased (P < 0.08) in pigs fed phytase, but many other response variables were numerically affected by phytase addition. In Exp. 2, phytase had no effect (P > 0.10) on ADG, ADFI, gain:feed, LMA, or 10th-rib fat depth. These results suggest that phytase had small, mostly nonsignificant effects on energy availability in diets for growing pigs; however, given that phytase increased most of the response variables measured, further research on its possible effects on energy availability seems warranted.

Phytate-degrading enzymes in pig nutrition

“…Unusually, however, phytase decreased feed intake by 6.6% (2.42 versus 2.59 kg day − 1 ) in this study. Shelton et al (2003) investigated the effects of adding 500 FTU kg − 1 phytase to maize-soy diets on several parameters in pigs including protein deposition. Phytase numerically increased carcass protein deposition by 7.1% (99.9 versus 93.3 g day − 1 ) and responses appeared to be more pronounced with lower intakes of metabolisable energy.…”

Effects of supplemental phytase on nutrient digestibility and performance of sows fed diets with high or low native phytase activity

“…Its inclusion in the diets for growing pigs increases the availability of phosphorus and some other minerals (Brady et al, 2002;Hanczakowska et al, 2009;Nitrayova et al, 2009;Jacela et al, 2010) and also the digestibility of organic nutrients (Johnston et al, 2004). It elevates protein and fat deposition as well (Sands et al, 2001;Shelton et al, 2003).…”

Níveis de energia metabolizável em rações formuladas com base no conceito de proteína ideal e suplementadas com fitase para leitões dos 15 aos 35 kg

“…Oliveira et al (2005) não encontraram diferenças significativas na taxa de deposição de proteína em leitões alimentados com rações com níveis crescentes de energia metabolizável, formuladas com base no conceito da proteína ideal. Por outro lado, esses resultados contrastam com aqueles obtidos Shelton et al (2003), que observaram que a deposição de proteína foi maior em suínos em crescimento alimentados com rações de maior nível energético.…”