Effects of a Solid-State Fermented Phytase on Phosphorus Utilization in Growing Pigs Fed Corn-Soybean Meal Diets: I. Growth Performance and Phosphorus Excretion
J.S. Park, S.D. Carter, J.D. Schneider, and T.B. Morillo
Story in Brief
Forty-two barrows were used to determine the effects of the addition of a solid-state fermented phytase complex (Allzyme SSF; Alltech, Inc) to low phosphorus (P), corn-soybean meal diets on growth performance and P excretion. Pigs were allotted randomly to one of seven dietary treatments (6 pigs/trt). A basal diet consisted of corn and soybean meal and was adequate in all nutrients, except Ca and P. This diet contained .34% total P (.07% available P), all of which was provided by corn and soybean meal. Treatments were the basal, the basal plus monosodium phosphate (MSP) to provide .05, .10, and .15% added available P, and the basal plus enzyme to provide 250, 500, and 1,000 phytase units (PU)/kg. All diets were formulated to .95% total lysine and a Ca:total P ratio of 1.2:1. There were two 5-d total collection periods (d 10-15 and d 25-30) during the 33-d study. Daily gain and G:F increased with addition of MSP or SSF. However, ADFI was not affected by either addition of MSP or SSF. The addition of 500 or 1,000 PU/kg to the low P, corn-soybean meal diet increased ADG and G:F similar to that for pigs fed the highest level of MSP. Digestibility of dry matter, N, and energy were similar among treatments. Digestibility of P increased with addition of MSP or SSF. Compared to the basal diet, additions of SSF decreased P excretion by up to 45.4%. These data indicate that the addition of a solid-state fermented phytase improves growth performance and P utilization, and markedly reduces P excretion of pigs fed low P, corn-soybean meal diets.
Key Words: Pigs, Phytase, Excretion
Introduction
Phytate (myoinositol 1,2,3,4,5,6 hexa, dihydrogen phosphate) is the major form of P in cereal grains and oilseed meals (Reddy et al., 1982). Approximately 60 to 70% of the P in corn and soybean meal is in the form of phytate (NRC 1998). Unlike ruminant animals, monogastric animals, such as pigs and chicks, cannot utilize phytate due to the lack of endogenous phytase enzyme that cleaves phytic P (Peeler 1972). During the past decade, dietary phytases have been added to swine diets to improve P utilization, and ultimately, to decrease the amount of P excretion (Lei et al., 1993; Cromwell et al., 1995; O’Quinn et al., 1997). Many of the phytases used in the swine industry are produced by submerged microbial fermentation (SmF). Recently, solid-state fermentation (SSF) technology has been utilized as an alternative way to produce dietary phytase. Therefore, the purpose of this study was to determine the effects of the addition of a solid-state fermented phytase complex (Allzyme SSF; Alltech, Inc) to low P, corn-soybean meal diets on growth performance and P excretion in growing pigs.
Materials and Methods
A total of 42 crossbred barrows with an average BW of 19.9 kg were used in a 33-d study to investigate the effects of phytase addition on growth performance and P excretion of pigs fed corn-soybean meal based diets. Pigs were blocked by weight and randomly allotted to one of seven dietary treatments in a randomized complete block design. The corn-soybean meal based diets (Table 1) were fed as mash form. A basal diet consisted of corn and soybean meal and was adequate in all nutrients, except Ca and P. This diet contained .34% total P (.07% available P), all of which was provided by corn and soybean. Treatments were the basal, the basal plus monosodium phosphate (MSP) to provide .05, .10, and .15% added available P, and the basal plus enzyme to provide 250, 500, and 1,000 phytase units (PU)/kg. All diets were formulated to .95% total lysine and a Ca:total P ratio of 1.2:1. All other nutrients met or exceed NRC (1998) standards except Ca and P. The Ca: total P ratio in all diets was 1.2:1.
In this experiment, pigs were individually housed in metabolic
chambers in an environmentally-controlled room. The chambers were specially
designed for the total, but separate collection of feces, urine, and wasted
feed. Each chamber has a galvanized steel mesh floor and one stainless steel
self-feeder and one nipple waterer. Beneath the
floor, a five-quart plastic container was used to collect urine. All pigs
were allowed ad libitum access to feed and water. During
two 5-d collection periods (d 10-15 and d 25-30), feces were collected every
morning from the 1-mm screen under the chamber. The collected feces were
immediately weighed and frozen (-20°C) until the samples were analyzed. At the same time, refused feed
also was collected and weighed. Dry matter content of diets and feces was
determined by drying at 100°C for 24 h (AOAC, 1990). Nitrogen
content was determined by the Kjeldahl procedure
(AOAC, 1990) by automated analyzer (FOSS Tecator,
2020 Digestor, 2400 Kjeltec Analyzer; Hoganas,
Data were analyzed as a randomized complete block design using procedures described by Steel et al. (1997) with initial BW as the blocking criterion. The model included the effects of block (rep), treatment, and block × treatment (error). The model for digestibility included the effects of block (rep), treatment, period and treatment × period. The effects of MSP supplementation were tested for linearity and curvilinearity using orthogonal polynomial contrasts. For the four levels of phytase, polynomial coefficients for unequally spaced treatments were generated by the ORPAL matrix function of the IML procedure of SAS. In all cases, pig served as the experimental unit.
|
Table 1. Composition of experimental diets, as-fed basis |
|||||||
|
Diet |
|||||||
|
Total P, % |
.34 |
.39 |
.44 |
.49 |
.34 |
.34 |
.34 |
|
Available P, % |
.07 |
.12 |
.17 |
.22 |
.07 |
.07 |
.07 |
|
SSF phytase, PU/kg |
0 |
0 |
0 |
0 |
250 |
500 |
1,000 |
|
Corn |
72.07 |
72.07 |
72.07 |
72.07 |
72.07 |
72.07 |
72.07 |
|
Soybean meal |
25.25 |
25.25 |
25.25 |
25.25 |
25.25 |
25.25 |
25.25 |
|
Corn starch |
1.16 |
.78 |
.39 |
.00 |
1.14 |
1.11 |
1.06 |
|
Monosodium phosphate |
.00 |
.21 |
.43 |
.66 |
.00 |
.00 |
.00 |
|
Limestone |
.82 |
.99 |
1.16 |
1.32 |
.82 |
.82 |
.82 |
|
Sodium chloride |
.25 |
.25 |
.25 |
.25 |
.25 |
.25 |
.25 |
|
Vitamin & mineral premixa |
.25 |
.25 |
.25 |
.25 |
.25 |
.25 |
.25 |
|
Antibiotic |
.20 |
.20 |
.20 |
.20 |
.20 |
.20 |
.84 |
|
SSF phytaseb |
.00 |
.00 |
.00 |
.00 |
.03 |
.05 |
.10 |
|
Calculated analysis |
|||||||
|
Ca, % |
.41 |
.47 |
.53 |
.59 |
.41 |
.41 |
.41 |
|
Total P, %c |
.34 |
.39 |
.44 |
.49 |
.34 |
.34 |
.34 |
|
Available P, % |
.07 |
.12 |
.17 |
.22 |
.07 |
.07 |
.07 |
|
Added phytase activity, PU/kg |
0 |
0 |
0 |
0 |
250 |
500 |
1,000 |
|
a Provided the following per kg of diet: 5,506 IU of vitamin A, 551 IU of vitamin D, 33 IU of vitamin E, 3.6 mg of vitamin K (as menadione), 221 mg of biotin, 137 mg of choline, 33.04 mg of niacin, 24.78 mg of panthothenic acid (as d-pantothenate), 5.51 mg of riboflavin, 27.55 mg of vitamin B12, 1.66 mg of folacin, 100 mg of Zn, 2 mg of Mn, 100 mg of Fe, 10 mg of Cu, .30 mg of I, and .30 mg of Se. b Solid-state fermented phytase (Allzyme® SSF; Alltech, Inc) contains 1,000 PU/g of product. c Analyzed total P were 0.37, 0.43, 0.48, 0.52, 0.37, 0.37, and 0.37 %, respectively. |
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Results and Discussion
Growth performance. There was a linear effect (P<.03) of the addition of MSP on average daily gain and gain:feed (Table 2). Among the pigs fed diets with SSF phytase, ADG was linearly increased (P<.05) as SSF phytase increased from 0 to 1,000 units/kg. Adding 1,000 PU/kg of SSF phytase to the basal diet increased ADG and gain:feed by 17% and 9%, respectively. Average daily feed intake for 33 d was not affected (P>.29) by addition of MSP or SSF phytase. Compared to pigs fed the basal diet, ADG (P<.03) and gain:feed (P<.08) were greater for pigs fed SSF phytase-supplemented diets.
|
Table 2. Effects of monosodium phosphate and solid-state fermented phytase on growth performance of pigs fed low P, corn-SBM based dietsa |
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|
Diet |
||||||||
|
Total P, % |
.34 |
.39 |
.44 |
.49 |
.34 |
.34 |
.34 |
|
|
Available P, % |
.07 |
.12 |
.17 |
.22 |
.07 |
.07 |
.07 |
|
|
SSF phytase, PU/kg |
0 |
0 |
0 |
0 |
250 |
500 |
1,000 |
SE |
|
d 0- 33 |
||||||||
|
ADG, kg bcd |
.635 |
.671 |
.743 |
.720 |
.691 |
.742 |
.741 |
.027 |
|
ADFI, kg |
1.47 |
1.43 |
1.54 |
1.47 |
1.47 |
1.55 |
1.52 |
.05 |
|
Gain:feed bc |
.45 |
.47 |
.48 |
.49 |
.47 |
.48 |
.49 |
.01 |
|
a Least squares means for 6 pigs/trt, b Linear effect of added monosodium P (P<.05), c Linear effect of added phytase (P<.05), d None vs SSF phytase (P<.01) |
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Excretion and digestibility. There was no interaction between treatment and period (P>.50); thus, the data were pooled across period. Excretion and absorption of dry matter, energy and nitrogen were not affected (P>.10) by either the addition of monosodium phosphate or SSF phytase (Table 3). Among the pigs fed MSP, the amount of P excreted (g/d) was similar but P excretion based on the proportion of P intake was decreased (P<.01) by addition of monosodium phosphate. For the pigs fed SSF phytase, the amount of P excreted via feces decreased (linear, P<.01) as SSF phytase increased. Also, supplementation of SSF phytase linearly decreased P excretion expressed as a percentage of intake (P<.01). Compared to the basal diet, P excretion via feces was reduced by 23% and 46% with addition of 500 and 1,000 PU/kg, respectively. Also, digestibility of P was improved linearly (P<.01) from 44% to 70% when SSF phytase was added up to 1,000 PU/kg of diet.
|
Table 3. Effects of monosodium phosphate and solid-state fermented phytase on nutrient digestibility of pigs fed low P, corn-SBM based dietsa (DM basis) |
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|
Diet |
||||||||
|
Total P, % |
.34 |
.39 |
.44 |
.49 |
.34 |
.34 |
.34 |
|
|
Available P, % |
.07 |
.12 |
.17 |
.22 |
.07 |
.07 |
.07 |
|
|
SSF phytase, PU/kg |
0 |
0 |
0 |
0 |
250 |
500 |
1,000 |
SE |
|
Phosphorus |
||||||||
|
Intake, g/d |
5.50 |
6.02 |
7.66 |
7.66 |
5.49 |
5.83 |
5.68 |
.21 |
|
Feces, g/d c |
3.06 |
2.98 |
3.42 |
3.00 |
2.48 |
2.36 |
1.68 |
.15 |
|
Absorbed, g/d bcd |
2.43 |
3.16 |
4.24 |
4.66 |
3.02 |
3.48 |
4.01 |
.15 |
|
Excretion, % bcd |
55.9 |
50.3 |
44.2 |
39.2 |
45.2 |
40.5 |
29.5 |
1.6 |
|
Digestibility, % bcd |
44.1 |
49.7 |
55.8 |
60.7 |
54.8 |
59.5 |
70.5 |
1.6 |
|
DM, Energy, and N |
||||||||
|
DM digestibility, % |
88.1 |
87.6 |
87.3 |
88.3 |
87.9 |
88.6 |
88.2 |
.44 |
|
Energy digestibility, % |
86.9 |
86.2 |
85.8 |
87.2 |
86.5 |
87.2 |
86.1 |
.63 |
|
N digestibility, % |
83.8 |
82.7 |
82.6 |
84.1 |
83.1 |
85.3 |
84.0 |
.67 |
|
a Least squares means for 6 pigs/trt, b Linear effect of MSP (P<.01), c Linear effect of SSF phytase (P<.01), d None vs SSF phytase (P <.01). |
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Implications
The addition of solid-state fermented phytase to the low P, corn-soybean meal diets improved growth performance and phosphorus digestibility of growing pigs. This study indicates that the solid-state fermentation method used to produce this enzyme can be used as an alternative way to produce microbial dietary phytase. Addition of 1,000 PU/kg to low P, corn-soybean meal based diets resulted in 46% reduction in P excretion without affecting growth performance of growing pigs.
Literature Cited
AOAC. 1990. Official Methods of Analysis (16th Ed.). Association of Official Analytical Chemists, Arlington, VA.
Cromwell et al. 1993. J. Anim. Sci. 71: 1831.
Cromwell et al. 1995. J. Anim. Sci. 73: 449.
Cromwell et al. 1995. J. Anim. Sci. 73: 2000.
Lei et al. 1993. J. Anim. Sci. 71:3368.
NRC. 1998. Nutrient Requirements of Swine. 10th ed. National Academy Press, Washington, DC.
O’Quinn et al. 1997. J. Anim. Sci. 75:1299.
Peeler. 1972. J. Anim. Sci. 35:695.
Reddy et al. 1982. Advances in Food Research. P 1-92.
Steel, R.D.G. et al. 1997. Principle and Procedures of Statistics: A Biometrical Approach. 3rd ed. McGraw-Hill Publishing Co., New York.
Acknowledgments
The authors thank Alltech, Inc., (Nicholasville, KY) and USDA-CSREES (Federal Initiative Grant) for partial financial support and James Pierce (Alltech, Inc.) for technical assistant as well as providing the SSF Phytase used in this experiment.
Copyright 2003 Oklahoma Agricultural Experiment Station
[ 2003 Animal Science Research Reports | Animal Science Research Reports | Department of Animal Science ]