Addition Of Microbial Phytase Research Articles

248 Concentration of Net Energy in Corn without or with Microbial Phytase Fed to Group-Housed Pigs

Abstract The objective was to test the hypothesis that addition of microbial phytase to corn increases net energy (NE) by group-housed growing pigs. Three diets were formulated. The positive control (PC) diet contained corn as the sole source of energy. The PC diet contained Ca and P at the requirements for pigs (NRC, 2012). The negative control (NC) diet was similar to the PC except that this diet contained 0.08% standardized total tract digestible P and 0.12% total Ca less than the PC diet. The third diet was similar to the NC diet with the exception that this diet contained 1,000 units of phytase per kg diet. Pigs were allowed ad libitum access to feed and water. Pigs (n = 24; initial body weight = 44.99 kg; SD = 2.09) were allotted to the 3 diets using a replicated 6 × 3 incomplete Latin square design with 6 chambers (i.e., 4 pigs/chamber) and 3 periods. Oxygen consumption and CO2 and CH4 production were measured during fed and fasting states and fecal and urine samples were quantitatively collected. The statistical model included diet as the fixed effect and chamber and period as random effects. Result indicated that the apparent total tract digestibility (ATTD) of dry matter and gross energy, energy excretion in feces, urine, and heat, and NE did not differ among the 3 diets (Table 1). However, concentrations of digestible energy (DE) and metabolizable energy (ME) in diets and in corn were less (P < 0.05) in the PC diet compared with the NC diet without phytase, but no difference was observed between the PC diet and the NC diet with phytase or between the 2 NC diets. The ratio between NE and ME was not different among diets, but ME to DE was increased (P < 0.05) by supplementation of phytase to the NC diet. In conclusion, concentrations of DE and ME in corn are less if more feed phosphate and limestone are used in diets. However, concentrations of NE were not affected by supplemental phytase or Ca and P levels, even though ME to NE was increased by supplemental phytase.

Standardized total tract digestibility of phosphorus in bakery meal fed to pigs and effects of bakery meal on growth performance of weanling pigs

Two experiments were conducted to test the hypotheses that microbial phytase improves the standardized total tract digestibility (STTD) of phosphorus (P) in bakery meal and that corn may be replaced by bakery meal in diets for weanling pigs without negative effects on growth performance. Two sources of bakery meal were used in experiment 1 and one of these sources was also used in experiment 2. In experiment 1, eighty weanling barrows (initial body weight: 14.25 ± 1.91 kg) were allotted to a randomized complete block design with 10 diets and 8 replicate pigs per diet. Two basal diets based on each source of bakery meal (i.e., bakery meal 1 and bakery meal 2) were formulated without addition of microbial phytase. Eight additional diets were formulated by adding 500, 1000, 1500, or 3000 units of microbial phytase to each of the 2 basal diets. Pigs were housed individually in metabolism crates and feces were collected quantitatively for 4 d after 5 d of adaptation. Results indicated that greater increases in apparent total tract digestibility and STTD of P were observed in bakery meal 1 compared with bakery meal 2 when phytase was added to diets (interaction, quadratic, P < 0.05). In the second experiment, 160 newly weaned pigs (initial body weight: 7.17 ± 0.94 kg) were randomly allotted to 5 treatments with 8 pens per treatment and 4 pigs per pen. A 2-phase feeding program was used with d 1–14 being phase 1 and d 15–35 being phase 2. A control diet, containing primarily corn, soybean meal, and no bakery meal was formulated in each phase. Four additional diets in each phase were formulated by replacing 250, 500, 750, or 1000 g/kg of corn in the control diet with bakery meal. Results indicated that for the overall 5-wk nursery period, increasing concentrations of bakery meal tended (linear, P = 0.064) to reduce average daily gain and reduced (linear, P < 0.01) gain to feed ratio of pigs, whereas blood indicators of energy and protein utilization were not affected. In conclusion, digestible P in bakery meal may be increased by including microbial phytase in the diets, but a full replacement of corn with bakery meal in diets for weanling pigs may reduce growth performance.

Phosphorus digestibility and phytate degradation in pigs fed wheat-based diets with different intrinsic phytase activity and added microbial phytase

ABSTRACT The objective of this study was to investigate the effect of variation in wheat-derived phytase activity on myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) degradation, inositol phosphate (InsP) isomer concentration and phosphorus (P) digestibility in pigs fed wheat-based diets. Additional effects of a microbial phytase supplementation were also studied. Three wheat genotypes (W1-W3) with an analysed phytase activity between 2760 and 3700 FTU/kg were used to formulate four experimental diets that included soybean meal and rapeseed meal but did not contain a mineral P supplement. DietW1-DietW3 only differed in the included wheat genotypes (W1-W3) at an inclusion level of 400 g/kg. DietW3+ contained W3 and a commercial 6-phytase supplementation at 500 FTU/kg diet. Eight barrows with an initial body weight of 27 kg were fitted with a simple T-cannula at the distal ileum and assigned to the four dietary treatments in a completely randomised row column design. The experiment included four periods of 12 d each. The first 5 d of each period were for diet adaptation, followed by collection of faeces (4 d), ileal digesta (2 d), and blood (last day). In DietW1-DietW3, the mean precaecal (pc) InsP6 disappearance was 48% and the mean pc P digestibility was 37% without a significant effect of the wheat genotype. The InsP6 disappearance measured in the faeces was close to complete in all treatments, and faecal P digestibility was not significantly affected by the wheat genotype (36% overall). The addition of microbial phytase caused a significant increase in pc InsP6 degradation (to 79%) and pc and total tract P digestibility (to 53% and 52%, respectively). The concentration of InsP6 degradation products in ileal digesta was not significantly affected by the wheat genotype, except for that of Ins(1,2,3,4,6)P5 and myo-inositol, which were higher in DietW3 than in DietW1 and DietW2. The added microbial phytase significantly reduced the concentration of InsP5 isomers in the ileal digesta and increased the concentrations of lower InsP isomers and myo-inositol. There were no significant effects of the added microbial phytase on pc amino acid digestibility; however, the wheat genotype exerted significant effects on the pc digestibility of Cys, Gly and Val. It was concluded that an increase in the intrinsic phytase activity of wheat achieved by crossbreeding was not reflected in InsP6 degradation and P digestibility in pigs fed wheat-based diets.

Digestibility of amino acids and concentration of metabolizable energy are greater in high-oil corn than in conventional corn when fed to growing pigs

Two experiments were conducted to test the hypothesis that the coefficient of standardized ileal digestibility (CSID) of amino acids (AA), concentrations of digestible energy (DE) and metabolizable energy (ME), and the coefficient of standardized total tract digestibility (CSTTD) of phosphorus (P) in high-oil corn is greater than in conventional corn. In experiment 1, 9 pigs (81.5 ± 5.9 kg) that had a T-cannula installed in the distal ileum were allotted to a triplicated 3 × 3 Latin square design with 3 diets and 3 periods for 9 replicates per diet. A nitrogen-free diet and 2 diets that contained conventional corn or high-oil corn as the only source of crude protein (CP) and AA were formulated. Results indicated that the CSID of CP and most AA was greater (P < 0.05) in high-oil corn than in conventional corn, which consequently resulted in greater concentrations of standardized ileal digestible AA in high-oil than in conventional corn. In experiment 2, 64 pigs (18.75 ± 2.2 kg) were housed in metabolism crates and allotted to a 2 × 4 factorial arrangement with 2 sources of corn (conventional corn or high-oil corn) and 4 levels of microbial phytase (0, 500, 1000, or 2000 phytase units/kg). Feces and urine were collected using the marker-to-marker approach with 5-day adaptation and 4-day collection periods. The digestibility of gross energy (GE) was not different between diets containing high-oil corn and diets containing conventional corn. However, because of the greater GE in high-oil corn than in conventional corn, concentrations of DE and ME in high-oil corn were greater (P < 0.01) than in conventional corn. Addition of microbial phytase to diets increased (P < 0.01) the CSTTD of P in both corn sources, and the CSTTD of P was greater (P < 0.01) in high-oil corn than in conventional corn. In conclusion, high-oil corn contained more standardized ileal digestible AA, DE, and ME than conventional corn. The CSTTD of P in high oil corn, regardless of phytase supplementation, was also greater than in conventional corn. These results indicate that high-oil corn has greater nutritional value than conventional corn when fed to pigs.

Nutritional value of a new source of fermented soybean meal fed to growing pigs.

Three experiments were conducted to test the hypothesis that the standardized ileal digestibility (SID) of amino acids (AA), concentrations of digestible energy (DE) and metabolizable energy (ME), and the standardized total tract digestibility (STTD) of P in a new source of fermented soybean meal (Fermex 200) are greater than in conventional soybean meal (SBM-CV). In experiment 1, 9 barrows (initial body weight: 9.17 ± 1.03 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to a triplicated 3 × 3 Latin square design. A nitrogen-free diet and 2 diets that contained cornstarch and SBM-CV or Fermex 200 as the sole source of crude protein (CP), and AA were formulated. Results indicated that there were no difference between SBM-CV and Fermex 200 for SID of CP and AA. In experiment 2, 24 growing pigs (initial body weight: 14.19 ± 1.18 kg) were housed individually in metabolism crates. Pigs were allotted to a corn-based diet or 2 diets that contained corn and SBM-CV or corn and Fermex 200. Feces and urine samples were collected using the marker-to-marker approach with 5-d adaptation and 4-d collection periods. Results indicated that the concentration of DE and ME in Fermex 200 were not different from DE and ME in SBM-CV. In experiment 3, 40 barrows (initial body weight: 11.01 ± 1.38 kg) were allotted to 1 of 4 diets with 10 replicate pigs per diet. Four diets were formulated to contain Fermex 200 or SBM-CV and either 0 or 1,000 units/kg of microbial phytase. Pigs were housed individually in metabolism crates. Fecal samples were collected as explained for experiment 2. Results indicated that the STTD of P in Fermex 200 was greater (P < 0.01) than in SBM-CV, but the addition of microbial phytase to the diets increased the ATTD and STTD of P in SBM-CV, but not in Fermex 200 (interaction; P < 0.01). In conclusion, the SID of AA and concentrations of DE and ME in Fermex 200 were not different from values determined for SBM-CV, but the STTD of P was greater in Fermex 200 than in SBM-CV if microbial phytase was not added to the diet.

Effects of microbial phytase on standardized total tract digestibility of phosphorus in hybrid rye, barley, wheat, corn, and sorghum fed to growing pigs.

An experiment was conducted to determine the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P in three varieties of hybrid rye and in one source of barley, wheat, corn, and sorghum. The STTD of P in each cereal grain was determined both without and with addition of microbial phytase. In total, 112 growing barrows (13.7 ± 1.3 kg initial BW) were allotted to a randomized complete block design with four blocks of 28 pigs. Pigs were randomly allotted to 14 diets with two replicate pigs per diet in each block, resulting in a total of eight replicate pigs per diet for the four blocks. Each diet contained one of the cereal grains as the sole source of P. There were two diets with each cereal grain with one diet containing no microbial phytase and the other diet containing 1,000 units of microbial phytase per kilogram of diet. In each period, fecal output was collected for 5 d following a 5-d adaptation period according to the marker-to-marker procedure. Among the diets that did not include microbial phytase, one hybrid of rye had greater (P < 0.05) STTD of P than wheat, corn, and sorghum, which is likely a result of the greater intrinsic phytase activity in rye than in the other cereal grains. Without microbial phytase, there was no difference in the STTD of P in the three hybrids of rye and barley. Among the diets containing microbial phytase, there was no difference in STTD of P among the three hybrids of rye, barley, and corn. The STTD of P in the three hybrids of rye with microbial phytase was 61.9%, 70.8%, and 63.0%, respectively. Overall, microbial phytase improved (P < 0.05) the STTD of P in all cereal grains, although the magnitude of the increase in STTD of P differed among the grains.

Effects of extrusion and microbial phytase on the apparent and standardized total tract digestibility of phosphorus in hemp hulls fed to growing pigs.

An experiment was carried out to determine the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P and the effects of extrusion and microbial phytase on ATTD and STTD of P in hemp hulls (HH). Thirty-six pigs (30.3 ± 2.7 kg) were randomly allotted to 1 of 6 experimental diets in a complete randomized design with 6 replicates per diet. A corn-soybean meal (SBM)-based basal diet was formulated. Two additional diets were formulated by replacing 40% of corn and SBM (on a 100% of total diet basis) with HH or extruded HH (EHH). The test ingredients, corn, and SBM were the only sources of P in the diets. Three additional diets were also prepared by supplementing 500 unit/kg of microbial phytase to the initial 3 diets (the corn-SBM basal diet and diets containing test ingredients). Pigs were fed experimental diets at 3 times the maintenance energy requirement (197 kcal ME/kg BW0.60). Results indicated that fecal P concentration and daily P output were reduced (P < 0.05) from pigs fed diets with dietary phytase compared with pigs fed diets without dietary phytase. The ATTD and STTD of P in experimental diets were not different. However, the ATTD and STTD of P in experimental diets supplemented with dietary phytase were increased (P < 0.05) compared with the diets without phytase. The ATTD and STTD of P in HH were 18.8% and 22.0%, respectively, whereas respective values for EHH were 22.5% and 26.3%. Extrusion had no effects on ATTD and STTD of P in HH. However, the ATTD and STTD of P in HH and EHH increased (P < 0.05) when dietary phytase was added to the diets. The concentration of Ca in feces and daily Ca output were reduced (P < 0.05) as a result of phytase supplementation. Addition of dietary phytase increased (P < 0.05) the ATTD of Ca in all experimental diets. In conclusion, the ATTD and STTD of P in HH fed to growing pigs were 18.8% and 22.0%, respectively. Respective values for EHH were 22.5% and 26.3%. Extrusion did not affect the ATTD and STTD of P in HH. However, the addition of microbial phytase to experimental diets increased the ATTD and STTD of P in diets and test ingredients and decreased fecal P output from pigs fed experimental diets. There was no interaction between extrusion and dietary phytase supplementation.

Tibia mineralization of chickens determined to meat production using a microbial phytase

The target of the research was 6-phytase of microbial origin. It was used in feed mixtures for chickens determined to meat production. Its effect has been studied in relation to the tibia mineralization by calcium, phosphorus and magnesium. 6-phytase is a product of Aspergillus oryzae. That was obtained by means of biotechnological processes of production of commercially available enzymes. It was incorporated in the feed mixtures 0.1%. In a 38-day feeding trial, 300 one-day-old, as hatched, Cobb 500 chickens determined to meat production (100 birds per group) were fed on one concentrations of dietary non-phytate phosphorus (2.32, 2.31 g.kg-1, respectively and supplemental microbial phytase (0 and 500 FTU.kg-1 feed mixtures). Control group was used to compare the results and control feed mixtures contained 4.5 g.kg-1 without microbial phytase. At days 40 it was selected 6 birds in every group, which were slaughter in accordance with the principles of welfare. Left tibias of every bird were used to determination of calcium, phosphorus and magnesium contents. According to in vivo, it was found that the addition of microbial phytase to reduced dietary non-phytate phosphorus increased concentrations of calcium (Ca), phosphorus (P) and magnesium (Mg) in tibia. The differences among groups were statistically significant (p &lt;0.05). It was concluded that reducing of dietary non-phytate phosphorus on the 2.32, 2.31 g.kg-1, respectively, by monocalcium phosphate and microbial phytase supplementation in feed mixtures facilitated tibia mineralization at chicken determined to meat production.

Effects of a high level of phytase on broiler performance, bone ash, phosphorus utilization, and phytate dephosphorylation to inositol.

An experiment was conducted to evaluate how the addition of microbial phytase influenced growth performance, bone mineralization, tissue P content, apparent digestibility and retention, and inositol phosphate (IP) concentrations in broilers fed diets with varying mineral matrices from 2 to 23 d of age. At 2 d of age, chicks were randomly allotted to receive 1 of 6 experimental diets arranged as a 3 × 2 factorial of mineral matrix [control diet with 1.0% Ca and 0.5% non-phytate phosphorus (NPP); mineral matrix 1 with 0.84% Ca and 0.35% NPP; and mineral matrix 2 with 0.77% Ca and 0.29% NPP] and phytase supplementation (0 or 1,500 FTU/kg). Feed intake was influenced (quadratic, P = 0.012) by the mineral matrix, but no interaction or main effect of phytase were observed. Phytase increased (P = 0.011) BW gain regardless of the mineral matrix applied. Feed efficiency was not influenced (P >0.05) by mineral matrix, phytase, or their interaction. Phytase increased bone ash content differentially across matrices (interaction, P <0.01), and tibia P content was lowest in birds fed matrix 2 and highest in the control (linear, P <0.05). Concentrations of P in muscle, spleen, and liver were not affected by treatment. An interactive effect (P <0.01) was observed for apparent ileal digestibility (AID) of P, where phytase increased AID in matrix 1. An interactive effect (P <0.01) was observed for apparent retention of P and Ca, where phytase reduced P and Ca retention in the control diet. A main effect (P <0.01) of mineral matrix was observed for AID of Ca, with birds fed matrix 1 having the lowest AID of Ca compared with control and matrix 2 treatments. Phytase influenced (P <0.05) IP concentrations differently across matrices. Overall, phytase and the mineral matrix, either as main effects or in an interactive manner, influenced growth performance, apparent nutrient digestibility and retention, bone and IP concentration responses in broiler chicks.

Femur morphometry, densitometry, geometry and mechanical properties in young pigs fed a diet free of inorganic phosphorus and supplemented with phytase

ABSTRACTThe study investigated in piglets the effect of replacing dietary inorganic P by addition of microbial phytase and its impact on performance, nutrient digestibility and on the geometrical characteristics and mineralisation of the femur. Sixteen pigs on day 58 of age were divided into two groups and fed either a diet free of additional inorganic phosphorus (P) and supplemented with phytase (Diet LP, 4.23 g total P/kg diet) or a diet with a mineral source of P and not supplemented with phytase (Diet SP, 5.38 g total P/kg diet). Performance data and the apparent total tract digestibility of nutrients were estimated between days 58 and 114, and 72 and 86 of age, respectively. On day 114 of age, the pigs were slaughtered, the femur was dissected and the mineral content and mineral density, maximum strength and maximum elastic strength, cortical wall thickness, cross-sectional area and cortical index were analysed. The growth performance and digestibility of nutrient fractions (with exception of P) did not differ between treatment groups. The P-digestibility was significantly higher in Group LP. The femur of pigs in Group LP had significantly greater cortical wall thickness, cortical index, bone mineral content, bone mineral density, maximum strength and maximum elastic strength than Group SP. Femur maximum strength and maximum elastic strength were correlated with cortical wall thickness and cortical index. Resulting from the different supply of digestible P, the femur geometrical, densitometric and mechanical properties of Group LP were better than those of Group SP. The mechanical properties of the femur of pigs depended more on its geometrical characteristics than on the degree of its mineralisation.

Effects of microbial phytase on the apparent and standardized total tract digestibility of phosphorus in rice coproducts fed to growing pigs.

The objectives of this experiment were to determine the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P and the effect of microbial phytase on ATTD and STTD of P in full-fat rice bran (FFRB), defatted rice bran (DFRB), brown rice, broken rice, and rice mill feed when fed to pigs. Ninety-six barrows (initial BW of 19.4 ± 1.4 kg) were allotted to 12 diets with 8 replicate pigs per diet in a randomized complete block design. A basal diet based on corn and soybean meal was formulated. Five additional diets containing corn, soybean meal, and each rice coproduct were also formulated, and the ratio between corn and soybean meal in these diets was similar to that in the basal diet. Six additional diets that were similar to the initial 6 diets with the exception that 1,000 units of microbial phytase were added to the diets were also formulated. The ATTD and STTD of P were calculated for each diet using the direct procedure, and the ATTD and STTD of P in each rice coproduct were calculated using the difference procedure. Results of the experiment indicated that the concentration of P in feces was reduced (P < 0.05) from pigs fed diets with microbial phytase compared with pigs fed diets without phytase. No differences were observed between the basal diet and the broken rice diet, but the ATTD and the STTD of P in those diets was greater (P < 0.05) than in all other diets both without and with phytase. Among the rice coproducts, the greatest (P < 0.05) ATTD and STTD of P were observed for broken rice regardless of inclusion of phytase. If no microbial phytase was used, the values for STTD of P in brown rice, FFRB, DFRB, and rice mill feed were not different, but if microbial phytase was included in the diet, ATTD and STTD of P in brown rice was greater (P < 0.05) than in FFRB, DFRB, and rice mill feed. The STTD of P in brown rice, FFRB, and rice mill feed was greater (P < 0.05) if microbial phytase was used than if no microbial phytase was used. Addition of microbial phytase to the diets also increased (P < 0.05) the ATTD of Ca regardless of the rice coproducts used. In conclusion, the STTD of P is greater in broken rice than in all other rice coproducts. The STTD of P in brown rice, FFRB, DFRB, and rice mill feed is relatively low due to the high concentration of phytate in these ingredients, but addition of microbial phytase will increase the STTD of P in most rice coproducts.

Apparent and standardized total tract digestibility by growing pigs of phosphorus in canola meal from North America and 00-rapeseed meal and 00-rapeseed expellers from Europe without and with microbial phytase.

An experiment was conducted to determine apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) by growing pigs of P in canola meal, 00-rapeseed meal, and 00-rapeseed expellers. Canola meal and 00-rapeseed meal are the coproducts produced after the residual oil has been solvent extracted from the prepressed canola seeds and 00-rapeseeds, respectively, whereas 00-rapeseeed expellers is the coproduct from 00-rapeseeds that have been only expeller pressed. Two hundred sixteen barrows (18.0 ± 1.5 kg initial BW) were allotted to 36 diets and 6 replicate pigs per diet. Five samples of canola meal from solvent-extraction crushing plants in North America, 8 samples of 00-rapeseed meal from solvent-extraction crushing plants in Europe, and 5 samples of 00-rapeseed expellers from mechanical-press crushing plants in Europe were used in the experiment. Eighteen diets were prepared by including 40% of each source of canola meal, 00-rapeseed meal, or 00-rapeseed expellers in 1 diet. Eighteen additional diets were formulated by adding 1,500 units of microbial phytase to the diets. The only source of P in the diets was canola meal, 00-rapeseed meal, or 00-rapeseed expellers. Pigs were placed in metabolism crates that allowed for total fecal collection. Pigs were fed at 2.5 times their estimated energy requirement for maintenance. Ingredients, diets, and feces were analyzed for P, and the ATTD and STTD of each source of canola meal, 00-rapeseed meal, and 00-rapeseed expellers were calculated. A value for endogenous P loss of 190 mg/kg DMI was used to calculate the STTD of P. Results indicated that the ATTD and STTD of P for canola meal were not different from values obtained in 00-rapeseed meal, and the ATTD and STTD of P in 00-rapeseed meal were not different from values for 00-rapeseed expellers. The ATTD and STTD of P increased (P < 0.001) from 44.99 and 48.82% to 64.08 and 67.97% for canola meal, from 46.77 and 50.36% to 63.53 and 67.29% for 00-rapeseed meal, and from 44.83 and 48.60% to 69.18 and 72.99%, respectively, for 00-rapeseed expellers by adding microbial phytase to the diets. In conclusion, although the concentration of ether extract is much greater in 00-rapeseed expellers than in 00-rapeseed meal and canola meal, the ATTD and STTD of P for these ingredients are not different, and addition of microbial phytase results in improved digestibility of P in canola meal, 00-rapeseed meal, and 00-rapeseed expellers.

Effect of phytase supplementation of diets with different levels of rice bran and non-phytate phosphorus on productive performance, egg quality traits, leukocytes profile and serum lipids of laying hens reared indoor under high environmental temperatures

A total of 288 32-wk-old Lohmann Selected Leghorn (LSL-Lite) laying hens were fed on corn-soyabean meal-based diets containing three concentrations of rice bran (RB; 0, 75 and 150 g/kg; equivalent to 1.8, 2.7 and 3.5 g/kg phytate phosphorus), two of non-phytate phosphorus (NPP; 2.5 and 3.5 g/kg) and two of microbial phytase (Phyzyme® XP 5000G; 0 and 150 FTU/kg) in a 10-wk trial under high temperature condition. The average minimum and maximum room temperatures were 26.0 ± 1.9 and 36.0 ± 1.8 °C, respectively, with relative humidity ranging from 42.3 ± 1.8% to 55.1 ± 2.1%. Each dietary treatment was fed to four cages (six birds/cage) from 32 to 42 wk of age. Egg production, egg weight and feed intake were recorded daily. Egg quality traits were recorded every 5 wk. Leukocyte subset counts and blood lipid profile were evaluated at the end of experiment. The results showed that inclusion of 150 g/kg RB negatively influenced (P < 0.05) egg production (EP), feed conversion ratio (FCR), shell weight and shell thickness. Significant reductions (P < 0.05) in the blood triglyceride and total cholesterol were observed with increasing dietary inclusion levels of RB. Although, dietary NPP levels did not influence any of the performance traits, the low-NPP diets caused a decrease (P < 0.05) in shell weight and shell thickness when compared with normal-NPP diets. The H/L ratio, as a stress indicator, was also increased (P < 0.05) by low-NPP diets. These adverse effects were partially overcome by the addition of microbial phytase (PHY). Supplemental PHY improved (P < 0.05) EP, FCR and unmarketable eggs but the magnitude of the responses was greater in low-NPP and high-RB treatments, resulting in significant RB × NPP × PHY interactions. Egg mass, shell weight and shell thickness were also improved (P < 0.05) by PHY addition but the response was greater at the highest concentration of RB, resulting in a significant RB × PHY interaction. Responses were also greater (P < 0.05) in low-NPP diets as indicated by significant NPP × PHY interaction. It can be concluded that the positive effects of PHY supplementation were clearly evident for laying hens reared under the high ambient temperatures pertaining to this study. At high concentration of phytate (high-RB diet) and/or low level of NPP (2.5 g/kg), response to supplemental PHY appears to be increase in terms of performance and egg quality in heat-stressed laying hens.

Bone mineralisation of weaned piglets fed a diet free of inorganic phosphorus and supplemented with phytase, as assessed by dual-energy X-ray absorptiometry

Sixteen female piglets (58 d of age, 16.8 ± 0.8 kg body weight [BW]) were assigned to two groups (n = 8) and received until day 100 of age (50.3 ± 1.2 kg BW) ad libitum either a diet with a standard (diet C) or low (diet L) total phosphorus (P) content (5.38 and 4.23 g/kg, respectively). Diet C was supplemented with mineral P (1.15 g/kg) and did not contain microbial phytase. Diet L did not contain any inorganic P but 750 FTU/kg of microbial phytase. Despite these treatments, both diets were composed with the same ingredients. Body mineralisation of each gilt was assessed by determining the bone mineral content (BMC), area bone mineral density (BMD) by the dual-energy X-ray absorptiometry (DXA) at days 58, 72, 86 and 100 of age. Feeding diet L caused a higher P digestibility (p = 0.008) measured from days 72 to 86 of age and at 100 days of age a higher BMC and BMD (p ≤ 0.01). Furthermore, the gilts of group L deposited more minerals in the body than control pigs (by 2.4 g/d, p = 0.008). It was found that BMD and BMC were positively correlated with body lean mass and digestible P intake. The results indicated that, even for very young pigs, the addition of microbial phytase instead of inorganic P increases the amount of digestible P covering the requirements of piglets for proper bone mineralisation. Furthermore, it was proved that the DXA method can be successfully applied to measure body fat and lean mass contents as well as bone mineralisation of growing pigs using the same animals.

Microbial phytase addition resulted in a greater increase in phosphorus digestibility in dry-fed compared with liquid-fed non-heat-treated wheat–barley–maize diets for pigs

The objective was to evaluate the effect of microbial phytase (1250 FTU/kg diet with 88% dry matter (DM)) on apparent total tract digestibility (ATTD) of phosphorus (P) in pigs fed a dry or soaked diet. Twenty-four pigs (65±3 kg) from six litters were used. Pigs were housed in metabolism crates and fed one of four diets for 12 days; 5 days for adaptation and 7 days for total, but separate collection of feces and urine. The basal diet was composed of wheat, barley, maize, soybean meal and no mineral phosphate. Dietary treatments were: basal dry-fed diet (BDD), BDD with microbial phytase (BDD+phy), BDD soaked for 24 h at 20°C before feeding (BDS) and BDS with microbial phytase (BDS+phy). Supplementation of microbial phytase increased ATTD of DM and crude protein (N×6.25) by 2 and 3 percentage units (P<0.0001; P<0.001), respectively. The ATTD of P was affected by the interaction between microbial phytase and soaking (P=0.02). This was due to a greater increase in ATTD of P by soaking of the diet containing solely plant phytase compared with the diet supplemented with microbial phytase: 35%, 65%, 44% and 68% for BDD, BDD+phy, BSD and BSD+phy, respectively. As such, supplementation of microbial phytase increased ATTD of P in the dry-fed diet, but not in the soaked diet. The higher ATTD of P for BDS compared with BDD resulted from the degradation of 54% of the phytate in BDS by wheat and barley phytases during soaking. On the other hand, soaking of BDS+phy did not increase ATTD of P significantly compared with BDD+phy despite that 76% of the phytate in BDS+phy was degraded before feeding. In conclusion, soaking of BDS containing solely plant phytase provided a great potential for increasing ATTD of P. However, this potential was not present when microbial phytase (1250 FTU/kg diet) was supplemented, most likely because soaking of BDS+phy for 24 h at 20°C did not result in a complete degradation of phytate before feeding.

Evaluation of nutrient equivalency of microbial phytase in hens in late lay given maize–soybean or distiller's dried grains with solubles (DDGS) diets

1. An experiment was conducted with 360 Lohmann LSL-Classic White Leghorn layers (64 weeks old) to evaluate the effects of supplementation of microbial phytase on production, egg quality, bone, selected manure parameters and feed costs. 2. Experimental diets were formulated as follows: (1) maize–soybean (CS), (2) CS+300 units of phytase (FTU)/kg diet which was formulated to recoup only calcium and available phosphorus equivalency for phytase (CS+PHYCa+P), (3) CS+300 FTU/kg diet which was formulated to recoup total nutrient equivalency for phytase (CS+PHYtotal), (4) CS+100 g/kg distiller's dried grains with solubles (DDGS), (5) DDGS+300 FTU/kg diet which was formulated to recoup only calcium and available phosphorus equivalency for phytase (DDGS+PHYCa+P), or (6) DDGS+300 FTU/kg diet which was formulated to recoup total nutrient equivalency for phytase (DDGS+PHYtotal). 3. Each dietary treatment was assigned to 4 replicate groups with 3 cages and 5 hens per cage. The hens were provided with feed and water ad libitum. The experiment lasted for 8 weeks. 4. CS+PHYCa+P, CS+PHYtotal, DDGS+PHYCa+P and DDGS+PHYtotal diets supplemented with phytase provided similar percentage egg production, egg weight, egg mass, exterior egg quality, initial and final body weight compared with phytase-free diets. 5. However, supplementation of phytase to the experimental diets and calculation of the total nutrient equivalency for enzyme caused increased feed intake and decreased feed conversion ratio and Haugh unit. 6. No differences in manure dry matter, crude ash, total nitrogen, tibia crude ash, calcium and phosphorus contents were found among the experimental diets. On the other hand, manure total phosphorus content was significantly decreased in the DDGS diet and diets supplemented with phytase in comparison to the CS diet. 7. It was concluded that the addition of microbial phytase to the CS-based diets or diets with DDGS of hens in late lay and using Ca and available P equivalency of enzyme in feed; formulation may provide an economic benefit and decrease the amount of phytate P excretion in the manure without compromising production and egg quality parameters.

Effect of phytase on nutrient digestibility, mineral utilization and performance in growing pigs

Two experiments were conducted to investigate the effect of microbial phytase addition to a low total phosphorus (tP) diet on the apparent faecal digestibility of nutrients and the N, P, Ca, Mg, Cu and Zn balance, and on the growth performance and tissue mineral concentration in growing pigs. Three experimental diets were used; the control diet (C) with 5.8g tP/kg without phytase, and two low tP diets (4.5g tP/kg) without phytase (LP−), or with 500FTU/kg of microbial phytase (LP+). All diets were formulated to be isoenergetic (13.59MJ ME/kg) and to have a similar digestible lysine:ME ratio. In experiment 1 (digestibility study), pigs were housed individually in metabolism cages and each diet was rotated three times according to 3×3 Latin square designs. Phytase supplementation resulted in higher P, Ca, Mg and Cu digestibilities and P and Cu retention, which could result in a decrease in the excretion to the environment of 39% and 33% for P and Cu, respectively. In Experiment 2 (growth performance and tissue mineral concentration study), phytase supplementation reversed the lower average daily feed intake and final body weight produced by the decrease of tP in growing pig diets. Neither alkaline phosphatase activity nor plasma Ca concentration was affected (P>0.05) by dietary treatment, but plasma inorganic phosphorus was higher in pigs fed the LP+ diet than in those fed the LP− diet. In addition, bone ash weight, peak breaking strength and the concentration of most of the minerals analysed on metacarpal bone were not affected by phytase supplementation, except for an increase in Mg concentration. No effects of phytase addition were observed on mineral concentration, except for increased Zn concentration in the pancreas of pigs fed LP+. In conclusion, under our study conditions, phytase supplementation improved the growth performance and digestibility of most minerals studied. P and Cu were the most likely minerals to be affected by the addition of phytase, increasing their retention, which represented a decrease in the excretion into the environment from pig manure by 39% and 33% for P and Cu, respectively. However, the mineral concentration in heart, liver and muscle were not affected by diet, meaning that it is inadvisable to take one organ as target to study the effects of phytase supplementation.

Phosphorus utilization in finishing broiler chickens: Effects of dietary calcium and microbial phytase

A decrease in dietary P, especially in finishing broilers (21 to 38 d old), is a crucial issue in poultry production from an environmental and economic point of view. Nevertheless, P must be considered together with other dietary components such as Ca and microbial phytase. Different corn and soybean meal-based diets varying in Ca [low (LCa) 0.37, medium (MCa) 0.57, and high (HCa) 0.77%], and nonphytate P [nPP; low (LnPP) 0.18 and high (HnPP) 0.32%] content were tested with and without microbial phytase [0 or 500 phytase units (FTU)/kg]. Feed intake, BW gain, bone mineralization, and mineral retention were examined in 144 Ross PM3 broilers (22 to 38 d old) reared in individual cages. Growth performance was not significantly affected by the treatments. Nevertheless, a numerical decrease of ADG and ADFI was observed in HCa-LnPP and LCa-HnPP associated with an increase of feed conversion ratio. Decreased dietary Ca reduced tibia ash content (Ca, linear: P < 0.001; quadratic: P = 0.034) and tibia ash weight for the highest level of nPP (Ca × nPP; P = 0.035). In parallel, increasing dietary Ca reduced the flow of retained P (P = 0.022) but also tibia ash weight in LnPP diets (Ca × nPP; P = 0.035). The responses of the animals in terms of tibia ash content and P retention were improved by the addition of microbial phytase especially for the lowest P diets (nPP × phytase, P = 0.021 and P = 0.009; respectively). Phytase increased dry tibia weight, bone breaking strength, and tibia diameter in broilers fed the highest Ca diets (Ca × phytase; P < 0.05). We conclude that is possible to decrease P levels in finishing broilers, if the Ca content is appropriate. Nevertheless, decreasing the dietary P and Ca cannot allow a maximization of bone mineralization, but the optimal threshold remains to be determined.

Effect of a novel phytase on growth performance, apparent metabolizable energy, and the availability of minerals and amino acids in a low-phosphorus corn-soybean meal diet for broilers

The addition of microbial phytase to diets for broiler chickens has been shown to improve the availability of phytate P, total P, some other minerals, and amino acids. In this study, the effect of a novel microbial phytase expressed by synthetic genes in Aspergillus oryzae on amino acid and mineral availability was assessed. Phytase was incorporated (1,000 and 2,000 U/kg) into low-P corn-soybean meal-based diets for broilers. Broilers received the experimental diets for 3 wk, and excreta were collected from d 18 to 21 for the determination of AME and mineral retention. On the 22nd day, the broilers were killed and the left leg removed and ileal digesta collected. Ileal phytate P and total P absorption, ileal amino acid digestibility, as well as the bone mineral content and bone mineral density were determined. Ileal phytate P absorption and absorbed phytate P content of the low-P corn-soybean meal diet were significantly (P < 0.05) higher after dietary inclusion of the novel phytase (49-60% and 65-77% higher, respectively). Apparent ileal total P absorption and apparent total P retention was 12 to 16% and 14 to 19% higher (P < 0.05), respectively, after dietary inclusion of phytase. The bone mineral content and bone mineral density in the tibia were 32 to 35% and 19 to 21% higher (P < 0.05), respectively, after dietary phytase inclusion. The apparent ileal digestibility of threonine, tyrosine, and histidine increased significantly (P < 0.05) by 14, 9, and 7%, respectively, after dietary inclusion of microbial phytase. Overall, the inclusion of a novel microbial phytase into a low-P corn-soybean meal diet for broiler chickens greatly increased phytate P and total P absorption, bone mineral content and density, as well as the digestibility of some amino acids.

Meta-analysis of phosphorus utilization by growing pigs: effect of dietary phosphorus, calcium and exogenous phytase

Optimizing phosphorus (P) utilization in pigs requires improving our capacity to predict the amount of P absorbed and retained, with the main modulating factors taken into account, as well as precisely determining the P requirements of the animals. Given the large amount of published data on P utilization in pigs, a meta-analysis was performed to quantify the impact of the different dietary P forms, calcium (Ca) and exogenous phytases on the digestive and metabolic utilization criteria for dietary P in growing pigs. Accordingly, the amount of phytate P (PP) leading to digestible P (g/kg) was estimated to be 21%, compared with 73% for non-phytate P (NPP) from plant ingredients and 80% for NPP from mineral and animal ingredients (P < 0.001). The increase in total digestible dietary P following the addition of microbial phytase (PhytM) from Aspergillus niger (P < 0.001) was curvilinear and about two times higher than the increase following the addition of plant phytase, which leads to a linear response (P < 0.001). The response of digestible P to PhytM also depends on the amount of substrate, PP (PhytM2 × PP, P < 0.001). The digestibility of dietary P decreased with dietary Ca concentration (P < 0.01) independently of phytase but increased with body weight (BW, P < 0.05). Although total digestible dietary P increased linearly with total NPP concentration (P < 0.001), retained P (g/kg), average daily gain (ADG, g/day) and average daily feed intake (ADFI, g/day) increased curvilinearly (P < 0.001). Interestingly, whereas dietary Ca negatively affected P digestibility, the effect of dietary Ca on retained P, ADG and ADFI depended on total dietary NPP (NPP × Ca, P < 0.01, P < 0.05 and P < 0.01, respectively). Increasing dietary Ca reduced retained P, ADG and ADFI at low NPP levels, but at higher NPP concentrations it had no effect on ADG and ADFI despite a positive effect on retained P. Although the curvilinear effect of PhytM on digestible P increased with PP (P < 0.001), this effect was lessened by total NPP for ADG and ADFI (PhytM × NPP and PhytM2 × NPP, P < 0.05) and depended on both total NPP and Ca for retained P (PhytM2 × NPP × Ca, P < 0.01). This meta-analysis improves our understanding of P utilization, with major modulating factors taken into account. The information generated will be useful for the development of robust models to formulate environmentally friendly diets for growing pigs.