Performance of starter pigs fed with phytase supplemented diets formulated using standardized total tract digestibility (STTD) in rice bran
2012
Acda, S.P. | Abellila, J.J.
Two studies were conducted to determine the standardized total tract digestible (STTD) phosphorus (P) in rice bran with corn and soybean meal (SBM) as reference ingredients. The objectives of the first study were to determine the STTD P values in the ingredients with and without phytase when fed to growing pigs and estimate P release using in vitro procedure. The second study aimed to determine the effects of diets formulated with the same level of STTD P on the growth performance of growing pigs regardless of total and available P level. In study 1, 36 barrows (PIC L337 x C 24, initial BW = 22.3 + or - 1.4 kg) were randomly allotted to six semi-purified diets with each ingredient as the sole source of P with and without phytase supplementation. Each pig was housed in metabolism cages that allowed total collection of feces. In study 2, the same set of animals (initial BW = 33.0 + or - 2.7 kg) were randomly allotted to four corn SBM based diets following a 2x2 factorial in a randomized complete block design. Factors were phytase (0 and 500 FTU/kg) and rice bran (0 and 10%), with initial body weight as a blocking factor. All diets were formulated to contain 0.31% STTD P and fed to growing pigs for 28 d. Results in study 1 showed that addition of phytase increased the STTD of P in corn from 53.38 to 73.35% (P0.005), in SBM from 46.12 to 73.05% (P0.05), and in rice bran from 49.76 to 64.43% (P0.05). For the in vitro release of P experiment, the in vitro release of P was highly correlated (r0.05) phytase x rice bran interaction in all the growth parameters measured. There was also no (P0.10) difference in ADG [average daily gain], ADFI [average daily feed intake], G:F [feed efficiency] and final BW [body weight] between pigs' diets with and without phytase and diets with 0 or 10% rice bran. In conclusion, addition of phytase improved the STTD of P in rice bran. The regression equation obtained in this study could be used to estimate the in vivo STTD of P. The growing pig diets can be formulated based on STTD of P. Supplementation of inorganic P can be reduced or eliminated without reducing animal performance when using phytase, rice bran or combination of phytase and rice bran in the diet.
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