Effect of increasing Buttiauxella phytase dose on nutrient digestibility and performance in weaned piglets fed corn or wheat based diets

A New Biosynthetic 6-Phytase Added at 500 Phytase Unit/kg Diet Improves Growth Performance, Bone Mineralization, and Nutrient Digestibility and Retention in Weaned Piglets and Growing-Finishing Pigs

Two experiments were performed to evaluate the effect of a biosynthetic 6-phytase added at 500 phytase unit (FTU)/kg diet on growth performance, bone mineralization, and nutrient digestibility and retention in weaned piglets and growing-finishing pigs. Experiments were performed on 90 weaned male and female piglets with an average initial body weight (BW) at 7.7 ± 0.73 kg, 26 days of age) and 300 male and female growing pigs (initial BW: 21.0 ± 3.44 kg) for 43 and 98 days in experiments 1 and 2, respectively. In each experiment, the animals were assigned to one of three treatments according to a randomized complete block design. The treatments consisted of a positive-control (PC) diet formulated to meet nutrient requirements; a negative-control (NC) diet reduced similarly in calcium (Ca) and digestible P by 0.15 and 0.12% points in phases 1 and 2, respectively, in piglets and by 0.14, 0.11, and 0.10% points, respectively, in phases 1, 2, and 3 in growing-finishing pigs, compared with PC diet; and a NC diet supplemented with the new 6-phytase at 500 FTU/kg diet (PHY). The dietary P and Ca depletion reduced (p < 0.05) the final BW (-11.9%; -7.8%,), average daily gain (ADG, -17.8%; -10.1%), average daily feed intake (ADFI, -9.9%; -6.0%), gain-to-feed (G:F) ratio (-8.9%; -4.6%), and apparent total tract digestibility (ATTD) of P (-7.7% points; -6.7% points) in nursery piglets and growing pigs, respectively. It also decreased (p < 0.001) P and Ca retention by 6.1 and 9.4% points, respectively, in nursery pigs and ash, P, and Ca contents in metacarpal bones by 18.4, 18.4, and 16.8%, respectively, in growing pigs. Compared to animals fed the NC diet, phytase supplementation improved (p < 0.001) the final BW (+7.7%; +11.3%), ADG (+12.5%; +15.0%), G:F ratio (+8.4%; +5.8%), ATTD of Ca (+10.8% points; +7.2% points), and ATTD of P (+18.7% points; +16.6% points) in weaned piglets and growing pigs, respectively. In addition, phytase also increased (p < 0.001) P and Ca retention by 6.1 and 9.4% points, respectively, in nursery pigs and ash, P, and Ca contents in metacarpal bones by 17.7, 15.0, and 15.2%, respectively, in growing pigs. The final BW, ADG, G:F ratio, and bone traits in animals fed the NC diet supplemented with phytase were comparable to animals fed the PC diet. This finding indicates the ability of this novel biosynthetic phytase to restore performance and bone mineralization by improving the availability of P and Ca in piglets and growing pigs fed P- and Ca-deficient diets.

Phytase Supplementation of Growing-Finishing Pig Diets with Extruded Soya Seeds and Rapeseed Meal Improves Bone Mineralization and Carcass and Meat Quality

The aim of this study was to determine how different doses of phytase in diets with extruded soybean seeds and rapeseed meal affected pigs' growth performance, meat quality, bone mineralization, and fatty acid profiles. Sixty pigs were divided into three treatments by sex and body mass. Pigs were divided into starter (25 days), grower (36 days), and finisher (33 days) periods and fed with mash diets. No phytase was used in the control group diet, whereas in Phy1 and Phy2, 100 g and 400 g of phytase per ton of mixture were used, respectively. The feed conversion ratio and meat color were significantly correlated with phytase. Phytase supplementation had no effect on the growth of pigs, but total phosphorus was significantly increased in the bones and meat of the pigs. The enzyme additive reduced the C22:4 n-6 acid content in the meat, whereas other results were not significantly affected. The data suggest that the addition of phytase at a dosage of 100 g/ton to diets with extruded full-fat soya seeds and rapeseed meal can be valuable, as it reduces the FCR and increases the P content in the meat and bones.

Microbial Phytase in a Diet with Lupine and Extruded Full-Fat Soya Seeds Affects the Performance, Carcass Characteristics, Meat Quality, and Bone Mineralization of Fatteners

This study aims to determine how different doses of phytase in diets including extruded soya and lupine seeds affect fatteners' performance, meat quality, bone mineralization, and fatty acid profile. Sixty pigs were divided into three treatment groups. The control group was offered a diet without phytase, whereas the Phy100 and Phy400 groups were provided with 100 g and 400 g of phytase per ton of their diet, respectively. The animals from both experimental groups were characterized by a significantly (p < 0.05) higher body weight gain and lower feed efficiency in the starter period than the control group. Unfortunately, their meat had lower (p < 0.05) fat content, gluteal muscle thickness, and water-holding capacity. In the meat, a higher phosphorus content (p < 0.05) was found, and in the bones, a higher calcium (for Phy400) content was found when phytase was added to the pigs' diet. The pigs from the Phy100 group tended to have higher mean backfat thickness and C18:2 n-6 content in their fat, but lower C22:5 n-3 content, than the other groups. A higher dosage of phytase is not necessary for the diets of fatteners with extruded full-fat soya and lupin seeds.

Effects of dietary supplementation with microbial phytase on the growth, bone minerals, antioxidant status, innate immunity and disease resistance of African catfish fed on high soybean meal-based diets

The microbial phytase, derived from Buttiauxella gaviniae, Yersinia mollarettiv and Hafnia spp., is proven to be safe for avian and porcine feeding and promotes their overall growth performance. Here, we have evaluated microbial phytase's effects on the growth, bone mineral content, antioxidant status, immune responses and the resistance of African catfish (Clarias gariepinus) fed with high soybean meal-based diets against Aeromonas hydrophila infection. Five isonitrogenous diets (40% protein) were supplemented with different levels of microbial phytase ranging from 0 as a control to 250, 500, 750 and 1000 FTU/kg diet. African catfish (n = 300; 8.5 ± 0.3 g) were allocated in 15 50-L tanks (in triplicates) and were fed on the prepared tested diets for 12 weeks. After the end of the feeding period of 12 weeks, 10 fish from each replicate was intraperitoneally infected with A. hydrophila (0.5 × 10⁵ CFU/ml) and monitored for 14 days. Dietary phytase levels linearly and quadratically improved the growth performance of African catfish and stimulated feed intake. Bone levels of calcium, phosphorus, magnesium and zinc were also positively modulated in phytase-fed fish, especially at 750-1000 FTU/kg diet. Similarly, counts of red and white blood cells as well as haemoglobin, packed cells volume, platelets, lymphocytes and heterocytes were significantly modulated in all fish fed with phytase-supplemented diets. Higher levels of serum total protein, albumin and globulin were also observed in fish fed with a 750-1000 FTU/kg diet of phytase. Conversely, aspartate and alanine aminotransferase activities were lower in fish fed with a 750-1000 FTU/kg diet of phytase, compared to those fed the control diet. Moreover, antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase), reduced glutathione levels and immune responses (lysozyme, respiratory burst, protease and alkaline phosphatase activities) biomarkers were linearly and quadratically elevated, while malondialdehyde values were linearly and quadratically decreased in fish groups fed with phytase-based diets. After administering A. hydrophila, 60.0% of the fish fed the control diet perished, while no mortalities were observed in fish fed with 750-1000 FTU/kg diets. Taken together, the current study reveals that dietary phytase could improve the growth performance, blood profile, bone mineralization, antioxidant activities, immunity and overall protection of African catfish against A. hydrophila infection. Dietary phytase may be efficiently used in the feeding of African catfish to enhance their overall performance and mitigate health conditions with optimum level of 900 FTU/kg diet.

The Growth Performance, Nutrient Digestibility, Gut Bacteria and Bone Strength of Broilers Offered Alternative, Sustainable Diets Varying in Nutrient Specification and Phytase Dose

This study assessed the use of locally sourced sustainable feed ingredients, rapeseed meal (RSM) and maize dried distiller grains with solubles (DDGS) in diets over traditional ingredients on the growth performance, bone strength and nutrient digestibility of broilers. This work also investigated the effects of supplementing exogenous phytase in two doses (500 vs. 1500 FTU/kg). Using male Ross 308 chicks (n = 320) assigned to receive one of four experimental diets: (1) Positive control diet 1 (PC1), a wheat, soya-based diet + 500 FTU/kg phytase. (2) Positive control diet 2, RSM/DDGS diet + 500 FTU/kg phytase (PC2). (3) Negative control (NC) reduced nutrient RSM/DDGS diet, no phytase. (4) The NC diet plus 1500 FTU/kg phytase (NC+). PC1 birds displayed higher feed intake and body weight gain consistently throughout the trial (p < 0.001) as well as increased body weight by 28 d and 42 d (p < 0.001). Whole-body dual emission X-ray absorptiometry (DXA) analysis revealed PC1 birds also had higher bone mineral density (BMD), bone mineral content (BMC), total bone mass, total lean mass and total fat mass than birds offered other treatments (p < 0.01). Diet had no significant effect on bone strength. Phytase superdosing improved the digestibility of dry matter (DM), neutral detergent fibre (NDF), gross energy (GE), calcium (Ca), potassium (K) and magnesium (Mg) compared to birds in other treatment groups. The phytase superdose also improved performance in comparison to birds offered the NC diet. Phytase superdosing increased the IP6 and IP5 degradation and increased the ileal inositol concentration of the birds. N excretion was lower for birds offered the traditional wheat−soya diet and highest for those offered the high-specification RSM/DDGS diet with a commercial dose of phytase. The addition of a phytase superdose to the negative control diet (NC+) reduced P excretion of birds by 15% compared to birds offered NC.

Efficacy of enhanced Aspergillus niger phytase on growth performance, bone quality, nutrient digestibility and metabolism in nursery pigs fed corn-soybean meal diet low in calcium and digestible phosphorous

Efficacy of Escherichia coli phytase (ASP) was evaluated in nursery pigs fed low Ca and digestible P corn and soybean meal diet. Piglets were weaned on day 21, fed a common commercial starter diet for 7 d, and assigned to pens (4 pigs/pen: 2 ♀ and 2 ♂) based on day 7 BW. Positive control (PC) and negative (NC) diets were formulated with similar energy and nutrients with exception of total Ca, total P, and digestible P concentrations being 79%, 67%, and 55% that of PC diet, respectively. Two other diets were formulated by adding ASP in NC at 500 and 1,000 FTU/kg. All diets had 0.2% TiO₂ indigestible marker. The diets were allocated to pens to give 6 replicates per diet and fed for 42 d. Feed intake and body weight were monitored at 14-d intervals. On day 42, 1 pig/pen was bled and euthanized to access blood and tissue samples. Analyzed total Ca and P in NC diet was 71% and 69% of concentration in PC diet. Recovery of phytase in pelleted diets was 66.2% and 73.5% for NC+500 FTU/kg and NC+1,000 FTU/kg diets, respectively. Between days 15 and 42, pigs fed NC diet grew slower and ate less feed than pigs fed the other diets. Overall (days 0–42), phytase in NC increased (P ≤ 0.05) ADG linearly and quadratically. On day 42, pigs fed PC, NC+500 FTU/kg, and NC+1,000 FTU/kg were +6.1, +5.9, and +7.1 kg heavier (P < 0.05) than pigs fed NC, respectively. Pigs fed PC and NC plus phytase exhibited higher (P = 0.003) G:F relative to NC pigs between days 15 and 28. Pigs fed NC diet had lower (P < 0.001) plasma P concentration, apparent total tract digestibility (ATTD) of Ca and P, and metacarpal and metatarsal bone attributes than pigs fed any other diets. Supplementation of phytase in NC linearly increased (P < 0.05) plasma P concentration, ATTD of Ca and P, and bone attributes. Specifically, phytase increased (P ≤ 0.025) dry weight, length, and ash weight in metacarpals and metatarsals. In conclusion, low total Ca and digestible P diet depressed growth and P utilization in piglets. Supplemental phytase improved performance in pigs fed NC linked to enhanced nutrients uptake and metabolism commensurate to pigs fed adequate total Ca and digestible P from inorganic source.

Effect of a novel consensus bacterial 6-phytase variant in grower pigs fed corn-soybean meal-based diets formulated with a full nutrient matrix and no added inorganic phosphorus

The capacity of a novel consensus bacterial 6-phytase variant (PhyG) to entirely replace dietary inorganic phosphorus (Pi) source in grower pigs fed diets with reduction of calcium (Ca), net energy (NE), and digestible amino acids (AA) was evaluated, using growth performance and apparent total tract digestibility (ATTD) of nutrients as outcome measures. A total of 352 mixed-sex pigs (initial BW 23.4 kg) were randomized to 4 treatments, 8 pigs/pen, and 11 pens/treatment. Diets were corn-soybean meal-based and formulated by phase (grower 1, 25 to 50 and grower 2, 50 to 75 kg BW). The positive control diet (PC) provided adequate nutrients and a negative control diet (NC) was formulated without Pi (1.2 g/kg ATTD P) and reduced in Ca (-0.12 to -0.13 percentage points), NE (-32 kcal/kg), and digestible essential AA (-0.004 to -0.026 percentage points) vs. PC. Two further treatments comprised the NC plus 500 or 1,000 FTU/kg of PhyG. Data were analyzed by ANOVA, mean contrasts and orthogonal polynomial regression. Nutrient reductions in the NC reduced (P < 0.05) average daily gain (ADG) during grower 1 and overall (73 to 136 d of age), increased (P < 0.05) feed conversion ratio (FCR) during grower 1 and overall and tended to reduce (P < 0.1) average daily feed intake (ADFI) during grower 2 and overall, vs. PC. Phytase supplementation improved (P < 0.05) FCR during grower 1, ADG during grower 2 and overall, ATTD of DM and P, and tended to improve DE (P = 0.053) in a linear dose-dependent manner. PhyG at 1,000 FTU/kg resulted in growth performance (all measures, all phases) equivalent to PC. The findings demonstrate that PhyG at 1,000 FTU/kg totally replaced Pi in complex grower pig diets containing industrial co-products, compensated a full nutrient matrix reduction and maintained performance.

Effect of Two Different Biochars as a Component of Compound Feed on Nutrient Digestibility and Performance Parameters in Growing Pigs

The objective of this study was to examine two different biochars as a component of compound feed regarding their effects on nutrient digestibility and performance parameters in growing pigs. A total of 18 male, intact piglets (N = 18) with 26 days of age and an initial bodyweight of 6.88 kg were divided into three homogeneous groups of six animals each (n = 6). Treatments were control (CON, no addition of biochar), 2% biochar 1 (BC 1, diet containing 2% biochar 1), and 2% biochar 2 (BC 2, diet containing 2% biochar 2). Before the start of the trials, the biochars were characterized regarding Brunnauer-Emmet-Teller (BET) surface area, surface energy, humidity, and ash content. During the first trial (weeks 1–6) a 3 × 3 Latin square was used to determine the apparent total tract digestibility (ATTD) of all three feed in each animal (N = 54, n = 18). By start of the second trial on day 42, three new homogenous groups were formed with two animals from each of the previous groups. Each group received one of the three diets for 4 weeks. In the first trial, the ATTD of dry matter, organic matter, ether extract, crude fiber, and N-free extract was higher (p &lt; 0.05) in pigs fed the biochar diets (BC1 and BC2) than in those animals fed the control diet. The greatest difference was found for ATTD of crude fiber, which was increased by 19.8 and 23.8%, respectively (CON: 30.8b ± 13.4%; BC 1: 38.4a ± 8.2%; BC 2: 40.4a ± 12.2%). ATTD of crude protein was only higher in BC 2 compared to CON (CON: 81.0b ± 4.1%; BC 1: 82.4ab ± 3.6%; BC 2: 84.2a ± 3.4%). In both trials, the different treatments revealed no effects on ADFI, ADWG or G:F (p &gt; 0.05). The results indicate that no negative effects can be expected when 2% biochar is included in the feed for growing pigs.

Effects of a novel E. coli phytase expressed in Pseudomonas fluorescens on growth, bone mineralization, and nutrient digestibility in pigs fed corn-soybean meal diets

Two studies were conducted to determine the effects of a novel Escherichia coli phytase expressed in Pseudomonas fluorescens on growth performance, bone mineralization, and nutrient digestibility in pigs fed corn-soybean meal diets. In experiment 1, 160 nursery pigs (9.79 ± 1.22 kg) were randomly allotted to one of four treatments with 10 pens per treatment and four pigs per pen. Phase I and phase II diets were provided from d 0 to d 14 and d 14 to d 28, respectively. Treatments included: positive control (PC) with all nutrients meeting requirements; negative control (NC) with standardized total tract digestible (STTD) P reduced by 0.15% and 0.14% compared with PC in phase I and phase II, respectively; and NC diets containing 250 or 500 units of phytase (FTU) per kilogram. Results demonstrated that pigs fed PC had greater (P < 0.01) ADG and G:F for the overall experimental period, and greater (P < 0.01) bone ash and P concentrations, compared with pigs fed NC or diets with phytase supplementation. Pigs fed diets containing phytase had greater (P < 0.01) ADG and G:F for the overall experimental period compared with pigs fed the NC diet without phytase, and bone ash and P weights were increased (P < 0.01) as well. In experiment 2, 63 growing barrows (56.25 ± 2.54 kg) were blocked by BW and randomly allotted to one of seven treatments with nine pens per treatment and one pig per pen. A basal corn–soybean meal diet was formulated to meet nutrient requirements for growing pigs with the exception that STTD P was reduced by 0.18% compared with the requirement, and Ca was included to achieve a Ca:STTD P ratio of 2.15. Six additional diets were formulated by adding 250, 500, 750, 1,000, 1,500, or 2,000 FTU/kg of phytase to the basal diet. Pigs were fed experimental diets for 12 d with 7 d of adaptation and 5 d of fecal sample collection. Results indicated that there was a linear (P < 0.01) increase in apparent total tract digestibility of ash and ether extract, and STTD of Ca and P also increased (linear, P < 0.05) in response to increasing doses of phytase. Increasing phytase levels in the diets resulted in increase (quadratic, P < 0.05) in apparent ileal digestibility of Arg, His, Ile, Lys, Trp, Asp, and Glu. In conclusion, the novel E. coli phytase was effective in increasing growth performance, bone mineralization, and Ca and P digestibility in pigs fed corn–soybean meal-based diets. Results also indicated that this phytase had the potential to enhance the digestibility of fat and certain AA.

Effect of supplementing phytase on piglet performance, nutrient digestibility and bone mineralisation

Incremental levels of the phytase, OptiPhos® Plus, were fed to 150 weaned piglets (five treatments of 30 pigs) to determine the effect on piglet performance, nutrient digestibility and bone mineralisation. Piglets were fed a basal diet from four to six weeks and a pre-starter diet from six to ten weeks of age. The basal diets contained reduced digestible phosphorus (P) and calcium (Ca) (1.5 g/kg digestible P, and Ca 5.5 g/kg and 5.6 g/kg for weaner and pre-starter, respectively) to provide a negative control. Phytase was added at 0, 125, 250, 500 and 1000 phytase units (FTU)/kg feed. Faecal samples were collected at nine weeks of age and analysed for P, Ca and crude protein (CP) content to calculated digestibility. Metacarpal bone IV mineralisation was assessed by ash content and the weight and length of the bone. Incremental increases of phytase improved final body weight (BW) (P<0.001), average daily gain (ADG) (P<0.001) and feed conversion ratio (FCR) (P<0.01). The statistical model predicted a linear increase for daily feed intake (DFI), ADG and BW with increased phytase increments. BW at the end of the trial increased by 824 g per increase of 250 FTU/kg (P<0.001). ADG and DFI increased by 19 g/day (P<0.001) and 18 g/day (P<0.05) respectively, per increase of 250 FTU/kg. As the effect on ADG and final BW was higher at lowest doses, a quadratic effect for these parameters was observed, within the measured range of phytase levels (P=0.029 and 0.028, respectively). A reduction of 0.03 in FCR was observed for each 250 FTU/kg increase (P<0.01). For each increase in 250 FTU/kg, bone dry weight increased by 131 g (P<0.05) and bone ash concentration by 1.9% of fat free dry matter (P<0.001). The results showed that the addition of phytase to piglet diets low in P led to better utilisation of phytate-P and consequently better piglet performance.

Influence of Phytase Supplementation at Increasing Doses from 0 to 1500 FTU/kg on Growth Performance, Nutrient Digestibility, and Bone Status in Grower-Finisher Pigs Fed Phosphorus-Deficient Diets

Simple Summary

The current study investigates the growth performance and bone status of grower–finisher pigs supplemented with phytase, an enzyme which increases the bioavailability of phosphorus in animal feeds. The study results provide new information with regards to the positive role phytase supplementation to livestock feed plays in the achievement of the maximum effectiveness of the feed, as well as numerous positive effects on bone characteristics (geometry, mineralization, and mechanical strength) in grower–finisher pigs.

Abstract

The objective of the current study is to assess the effects of the inclusion of 6-n phytase to a phosphorous-deficient diet on the growth performance (feed intake, average daily gain, and feed conversion ratio), apparent digestibility of calcium and phosphorus, and bone characteristics of grower–finisher pigs. The experimental diets included a phosphorus-deficient diet containing 0 (negative control), 250, 500, 1000, or 1500 FTU/kg of 6-phytase, and a diet formulated to meet the phosphorus nutrient requirements of pigs (positive control). Pigs were fed the experimental diets from the time they were ~35 kg body weight until they reached slaughter weight of ~110 kg. Bone status of the metacarpal (ash, mineral content) and femur (mineralization, geometry, and mechanical strength) bones were assessed. There was no effect of dietary treatment on feed intake. Feed conversion ratio was improved following inclusion of phytase at a dose of 500 FTU/kg or higher. Phytase inclusion at a dose of 1000 FTU/kg increased the average daily weight gain of grower–finisher pigs. Phytase inclusion at a dose of 500 FTU/kg was sufficient to increase metacarpal phosphorus content. Femur mid-diaphysis ash percentage was significantly increased even after the inclusion of the lowest dose of phytase. Analysis of structural parameters of femur mechanical strength (Young’s modulus, yield stress, yield strain, ultimate stress, ultimate strain) showed that the inclusion of a phytase dose of 500 FTU/kg in growing/finishing diets was sufficient to significantly improve bone status of grower–finisher pigs at slaughter.

Effect of Phytase Derived from the E. coli AppA Gene on Weaned Piglet Performance, Apparent Total Tract Digestibility and Bone Mineralization

Simple Summary

Plants store phosphorus mainly in a form that is indigestible to pigs: phytate. Unabsorbed minerals excreted into the environment are considered to be environmental pollutants. Our study focuses on the effects of novel types of phytase enzymes in diets deficient in external phosphorus on the performance, digestibility of crude protein, dry matter and minerals, and bone mineralization of weaned piglets. Using novel phytases, we noted a positive impact on body weight gain, feed conversion ratio, the digestibility of phosphorus and calcium, and phosphorus and calcium content in bones. There was no significant improvement in the content of dry matter or digestion of crude protein. This study reveals novel phytases to be useful additives for weaned piglet diets because of their superior performance results and phosphorus absorption.

Abstract

The objective of this study was to assess the effect of novel appAT1 and appAT2 phytase inclusion at 250 phytase units (FTU)/kg on weaned piglet performance, the apparent total tract digestibility of P and Ca, and bone mineralization. Piglets (48 males) were randomly divided into four treatment groups: a positive control (PC), with recommended levels of phosphorus (P) and calcium (Ca), a negative control (NC) deficient in P and Ca, and two experimental groups with NC diets supplemented with phytase derived from the appA gene of Escherichia coli. Diets fed in a mashed form were divided into prestarter (0–21 days) and starter (22–42 days) periods. During the whole period of the study, the experimental diets improved (p < 0.05) the body weight gain (BWG) and feed conversion ratio (FCR) compared to the NC diet. The apparent total tract digestibility (ATTD) of the dry matter and crude protein was not significantly different among the diets. Phytase-supplemented diets improved the ATTD of P (p < 0.05) and the ATTD of Ca (p < 0.05). Bone ash content in the third metacarpal and P and Ca content were improved among the phytase supplemented diets compared to the NC diet.

Functionality of a next generation biosynthetic bacterial 6-phytase in enhancing phosphorus availability to weaned piglets fed a corn-soybean meal-based diet without added inorganic phosphate

The utility of a next generation biosynthetic bacterial 6-phytase (PhyG) in restoring bone ash, bone phosphorus (P) content and performance in piglets depleted in P was evaluated. A total of 9 treatments were tested as follows. Treatment 1, a negative control (NC) diet; treatments 2, 3, 4, NC supplemented with 250, 500 or 1,000 FTU/kg of PhyG; treatments 5, 6, NC supplemented with 500 or 1,000 FTU/kg of a commercial Buttiauxella sp phytase (PhyB); treatments 7, 8, 9, NC supplemented with monocalcium phosphate (MCP) to provide 0.7, 1.4 and 1.8 g/kg digestible P, equating to a digestible P content of 1.8, 2.5 and 2.9 g/kg. The latter constituting the positive control (PC) diet with adequate P and calcium (Ca). The NC was formulated without inorganic P (1.1 g digestible P/kg) and reduced in Ca (5.0 g/kg). Additional limestone was added to treatments 7 to 9 to maintain Ca-to-P ratio between 1.2 and 1.3. A total of 162 crossed Pietrain × (Large White × Landrace) 21-d-old piglets (50% males and 50% females) were fed adaptation diets until 42 d old and then assigned to pens with 2 pigs/pen and 9 pens/treatment in a completely randomized block design. Piglets were fed mash diets based on corn and soybean meal ad libitum for 28 d. At the end of the study, one piglet perpen was euthanized and the right feet collected for determination of bone strength, bone ash and mineral content. Compared with the PC, the NC group had reduced average daily gain (ADG) and increased feed conversion ratio (FCR) during all growth phases and overall, and at d 28 (70 d old) NC pigs had bones with reduced ash, Ca and P content (P < 0.05). The PhyG at 250 FTU/kg improved bone ash vs. NC. Increasing PhyG dose linearly or quadratically improved bone ash, ADG and FCR (P < 0.05). At ≥ 500 FTU/kg, both PhyG and PhyB maintained ADG and FCR equivalent to PC. Linear regression analysis was done to compare the measured response parameters to increasing digestible P from MCP. Based on this analysis it was shown that PhyG and PhyB at 1,000 FTU/kg could replace 1.83 and 1.66 g/kg digestible P from MCP in the diet, respectively, on average across metacarpi bone ash, ADG or FCR. These findings suggest that the biosynthetic phytase is highly effective in the tested dietary setting.

Increasing the dosing of a Buttiauxella phytase improves phytate degradation, mineral, energy, and amino acid digestibility in weaned pigs fed a complex diet based on wheat, corn, soybean meal, barley, and rapeseed meal1

This study evaluated the effects of increasing the dose of a 6-phytase from Buttiauxella on phytate degradation, mineral, energy, and AA digestibility in weaned pigs fed complex diets based on wheat, corn, soybean meal, barley, and rapeseed meal. A negative control (NC) diet containing no added inorganic phosphorus (P) and a reduction of 0.1% calcium (Ca) and 36 kcal/kg ME was supplemented with Buttiauxella phytase at 0, 250, 500, 1,000, or 2,000 FTU/kg diet and tested against a nutritionally adequate, positive control (PC) diet. One phytase units (FTU) is the amount of enzyme that liberates 1 micromole of inorganic phosphate per minute from a sodium phytate substrate at pH 5.5 and 37 °C. Barrows (Topigs × Pietrian; initial mean body weight 19.3 kg) were housed individually in metabolic crates and fed the test diets in mash form via 2 equal meals per day for 9 d (fed at 2.5 times the maintenance energy requirement), with 8 replicate pigs per treatment, in 2 experimental runs (total n = 48). After a 3-d adaptation period, urine and feces were collected over 5 d for measurements of apparent total tract digestibility (ATTD) and retention of nutrients. On day 9, pigs were euthanized and ileal digesta collected for measurements of apparent ileal digestibility (AID) of nutrients. Phytase improved (P < 0.05) digestibility of all measured AA except Trp (P < 0.1), and AID P, nitrogen, phytate, ATTD P, Ca versus NC. Increasing phytase dose from 0 (NC) to 2,000 FTU/kg increased AID Lys, Cys, Thr, Val, Ile, Leu, mean AA, P, N, phytate, ATTD P, N, Na, energy, ME, P retention (g/d), and reduced P excretion (g/d) in a linear or exponential manner (P < 0.05). Phytase at 2,000 FTU/kg improved AA digestibility by between +3.1 percentage points (Trp) and +8.8 percentage points (Cys) versus NC (average +6.3 percentage points) (P < 0.05). Phytase inclusion at 2,000 FTU/kg reduced P excretion (g/d) by 57% versus PC (P < 0.05). In conclusion, increasing Buttiauxella phytase in the range of 0 to 2,000 FTU/kg increased phytate degradation, improved AA and P digestibility, and reduced P excretion in weaned pigs fed complex diets.

Effects of microbial phytase on mucin synthesis, gastric protein hydrolysis, and degradation of phytate along the gastrointestinal tract of growing pigs

An experiment was conducted to test the hypothesis that pigs fed diets supplemented with exogenous phytase reduce mucin synthesis in the small intestine, increase protein hydrolysis in the stomach, increase breakdown of phytate along the gastrointestinal tract, and increase mineral and AA digestibility. A diet based on corn, soybean meal, and canola meal was formulated to meet requirements for growing pigs except for Ca and P, which were lower than requirements. Three additional diets were formulated by adding 750, 1,500, or 3,000 units of phytase (FTU) per kilogram to the basal diet. Eight growing barrows (38.45 ± 3.06 kg) were prepared with a T-cannula in the duodenum and another T-cannula in the distal ileum. Pigs were housed individually and allotted to a replicated 4 × 4 Latin square design with four pigs and four periods in each square. Each period lasted 14 d with the initial 7 d being the adaptation period to the diets. Pigs were fed twice daily in combined amounts equal to 3.2 times the estimated requirement for maintenance energy. Results indicated that the apparent ileal digestibility (AID) and the apparent total tract digestibility (ATTD) of Ca and P increased (linear and quadratic, P ≤ 0.05) as phytase inclusion increased. However, values for AID of Ca and P were not different from values for ATTD of Ca and P, indicating that there is no net absorption of Ca and P in the hindgut. The apparent duodenal digestibility (ADD) of Ca and P was ~30% and 10% to 20%, respectively, indicating some digestion in the stomach of both Ca and P. A quadratic increase (P < 0.05) of the AID of GE was observed with the breakpoint around 1,500 FTU, but there was a negative linear (P ≤ 0.001) effect of dietary phytase on the ATTD of GE. Phytase did not affect mucin synthesis in the small intestine, protein hydrolysis in the stomach, or ileal digestibility of dispensable and indispensable AA. However, degradation of higher phytate esters (IP6 and IP5) into lower phytate esters (IP4 and IP3) and inositol increased as dietary phytase increased, indicating that it is possible to completely degrade dietary phytate if microbial phytase is included by at least 3,000 FTU in the diet. In conclusion, supplementing diets with phytase resulted in increased degradation of phytate and phytate esters and improved digestibility of Ca and P, but phytase did not change intestinal mucin synthesis, gastric protein hydrolysis, or the AID of AA.

Productive performance of commercial growing and finishing pigs supplemented with a Buttiauxella phytase as a total replacement of inorganic phosphate

The objective of this study was to test if a novel phytase from Buttiauxella sp. can replace all added inorganic phosphate in a diet with reduced Ca and metabolizable energy (ME) fed to commercial pigs from 12 kg body weight (BW) until slaughter, whilst maintaining performance and carcass quality parameters. Four dietary treatments were tested in a completely randomized design with 9 replicate pens, each containing 31 mixed sex Newsham Choice pigs. Diets included a positive control (PC) based on corn, soybean meal, wheat middling and bakery meal, meeting all nutrient requirement of pigs; a negative control (NC) excluded inorganic phosphate and with reduced Ca (-0.13%) and ME (-0.15 MJ/kg); and NC supplemented with Buttiauxella phytase at 500 or 1,000 FTU/kg feed. Diets were fed ad libitum in mash form in 5 phases: starter (12 to 25 kg BW), grower 1 (25 to 50 kg BW) and 2 (50 to 75 kg BW), and finisher 1 (75 to 100 kg BW) and 2 (100 kg BW to slaughter). The NC group showed lower (P < 0.05) average daily feed intake (ADFI) and average daily gain (ADG) in starter and grower phases, lower gain to feed ratio (G:F) in starter and grower 1 compared with PC. Pigs receiving the high dose of phytase of 1,000 FTU/kg had improved performance vs. the 500 FTU/kg phytase treatment in starter and grower 1 phase compared with the PC in grower 1 phase. Increasing phytase dose resulted in a linear increase in ADG (12 to 120 kg BW) and G:F (50 to 75 kg BW). A comparison of treatment groups over the full production period from 12 kg BW until slaughter showed that both 500 and 1,000 FTU/kg phytase treatments were able to maintain growth performance and carcass characteristics compared with PC. The application of Buttiauxella phytase could therefore be used as an effective strategy to replace all inorganic phosphate in diets of pigs fed corn, soybean meal, wheat middling and bakery meal based diets from 12 kg BW. An economic analysis showed greater return from both phytase treatments vs. the PC and favored the higher phytase dose at 1,000 FTU/kg vs. the traditional dose of 500 FTU/kg. The latter was mainly related to the improved performance of the higher dose in younger pigs to 75 kg BW.