Effect of phytase enzyme on dietary nitrogen-corrected apparent metabolizable energy and the ileal digestibility of nitrogen and amino acids in broiler chicks

The Effect of including a Mixed-Enzyme Product in Broiler Diets on Performance, Metabolizable Energy, Phosphorus and Calcium Retention

The importance of enzymes in the poultry industry is ever increasing because they help to extract as many nutrients as possible from the raw material available and reduce environmental impacts. Therefore, an experiment was conducted to examine the effect of a natural enzyme complex (ASC) on diets low in AME, Ca and P. Male Ross 308 broilers (n = 900) were fed one of four diets: (1) positive control (PC) with no enzyme added (AME 12.55 MJ/kg, AVPhos 4.8 g/kg and AVCal 9.6 g/kg); (2) negative control (NC) with no enzyme added and reduced AME, Ca and P (AME 12.18 MJ/kg, AVPhos 3.3 g/kg, AVCal 8.1 g/kg); (3) negative control plus ASC at 200 g/t; and (4) negative control plus ASC at 400 g/t. Broiler performance, digesta viscosity, tibia mineralization and mineral content were analyzed at d 21. Between d 18 and 20, excreted DM, GE, total nitrogen, Ca, and P were analyzed. ASC at 200 g/t and 400 g/t improved the FCR (p = 0.0014) significantly when compared with that of the NC. There were no significant differences in BW or FI between the treatments. Birds fed ASC at 200 g/t and 400 g/t had significantly improved digesta viscosity (p < 0.0001) compared with that of the PC and NC birds and had significantly higher excreted DM digestibility (p < 0.01) than the NC and the PC birds with 400 g/t ASC. ASC inclusion significantly improved P retention (p < 0.0001) compared to that in the PC. Ca retention was significantly increased by 400 g/t ASC compared to that in the PC and NC (p < 0.001). AME was significantly higher (p < 0.0001) for all treatments compared to that in the NC. There were no significant differences between treatments for any of the bone measurements. This study showed that feeding with ASC can support the performance of broilers when fed a diet formulated to have reduced Ca, P and AME, with the greatest results being seen with a higher level of ASC inclusion.

Impacts of phytase and coccidial vaccine on growth performance, nutrient digestibility, bone development, and intestinal gene expression of broilers fed a nutrient reduced diet

An experiment was conducted to evaluate effects of phytase and coccidial vaccine on growth performance, bone ash, bone 3-D microstructure, nutrient digestibility, and gene expression of intestinal biomarkers in broilers fed a regular or nutrient-reduced diet. The experiment was conducted in a 2 × 4 factorial arrangement with 6 replicates per treatment and 10 birds per replicate. Two main factors were coccidial vaccine and dietary treatments. The dietary treatments included: 1) a positive control (PC; normal nutrient levels); 2) a negative control (NC; with a reduction of 0.15% of Ca and avP and 5% of essential amino acid (EAA) and crude protein relative to PC); 3) NC + 500 FTU/kg of phytase; and 4) NC + 1,500 FTU/kg of phytase. No interaction effect of phytase and coccidial vaccine on growth performance, bone ash, and apparent ileal digestibility (AID) was observed. For the main effect, birds fed the NC diet showed lower (P = 0.007) BWG during d 0 to 21 compared to PC birds, whereas supplementing 500 or 1,500 FTU/kg phytase increased BWG to the similar level to the PC. During d 0 to 21, vaccinated birds had a lower (P < 0.001) FI and better (P = 0.045) FCR compared to unvaccinated birds. Birds fed the NC diet resulted a decrease in tibia fat-free dry bone weight (P = 0.012), ash weight (P = 0.005), ash percentage (P < 0.001), and ash concentration (P = 0.019) compared to the PC group at d 21, whereas supplementing phytase at 500 or 1,500 FTU/kg in NC diet was able to improve these bone parameters to the similar level to the PC; however, vaccination did not have any effect on bone ash. Similarly, birds fed with the NC diet showed had significant lower bone microstructure levels including bone volume, bone mineral density, and bone mineral content (P < 0.001), and supplementing phytase at 1,500 FTU/kg improved these parameters. Vaccination improved AID of nitrogen (P < 0.001). Birds from the NC and both phytase supplementation groups had a higher (P = 0.001) AID of Ca compared to the PC. Supplementing phytase at 500 FTU/kg or 1,500 FTU/kg improved (P < 0.001) AID of P compared to the NC. Additionally, the NC had a lower AID of DM than the PC, whereas supplementing phytase at 500 FTU/kg or 1,500 FTU/kg improved DM digestibility (P = 0.0299). In conclusion, supplementation of phytase at 500 or 1,500 FTU/kg improved growth performance, bone mineralization, and nutrient digestibility regardless of vaccination, with a more pronounced effect when supplementing phytase at 1,500 FTU/kg.

Effects of a novel consensus bacterial 6-phytase variant on the apparent ileal digestibility of amino acids, total tract phosphorus retention and tibia ash in young broilers

The effect of a novel consensus bacterial 6-phytase variant (PhyG) on apparent ileal digestibility (AID) of amino acids (AA) and phosphorus (P) utilization in young broilers when added to diets with high phytate-P (PP) content without added inorganic phosphate (Pi) and deficient in digestible (dig) AA and metabolizable energy (ME) was investigated. A total of 256 Ross 308 male broilers were assigned to 4 treatments (8 birds/cage, 8 cages/treatment) in a completely randomized design. Treatments comprised a positive control (PC, 2,975 kcal/kg ME, 3.7 g/kg dig P, 2.83 g/kg PP, 8.4 g/kg Ca, 10.6 g/kg dig lysine), a negative control (NC) without added Pi (ME −68 kcal/kg, crude protein −10 g/kg, dig AA −0.1 to −0.4 g/kg, Ca −2.0 g/kg, dig P −2.2 g/kg, Na −0.4 g/kg vs. PC), and NC plus 500 or 1,000 FTU/kg of PhyG. Test diets were corn/soy/rapeseed-meal/rice-bran-based and fed from 5 to 15 d of age. Ileal digesta and tibias were collected on day 15. Excreta was collected during days 12 to 15 to determine P retention. The NC (vs. PC) reduced (P < 0.05) P retention (−10.4% units), tibia ash (−14.3% units), weight gain (−109 g), feed intake (−82 g) and increased FCR (from 1.199 to 1.504), confirming that the NC was extremely deficient in nutrients and energy. Phytase addition to the NC linearly (P < 0.001) improved performance, but did not fully recover it to the level of the PC due to the severe nutrients/energy reduction in NC. Phytase linearly increased P retention (P < 0.001), tibia ash (P < 0.001), AID of dry matter (P < 0.05), nitrogen (P < 0.01), gross energy (P < 0.05), and all 17 individual AA (P < 0.01). At 1,000 FTU/kg, phytase increased (P < 0.05) P retention vs. PC and NC (+14.5 and +24.9% units, respectively) and increased tibia ash vs. NC (+13.8% units), equivalent to PC. The NC decreased AID of Cys, Gly, Thr, and Met vs. PC (P < 0.05). At 1,000 FTU/kg, phytase increased AID of all 17 AA vs. NC (P < 0.01), equivalent to PC. At 1,000 FTU/kg, AID AA responses (above NC) ranged from +4.5% (Met) to +15.0% (Cys), being maximal for essential Thr (+10.4%) and Val (+8.2%) and non-essential Cys (+15.0%) and Gly (+10.4%). The results highlight the efficacy of PhyG at a dose level of 500 to 1,000 FTU/kg in young broilers for improving the ileal digestibility of nitrogen, AA, and energy alongside P retention and tibia ash. The performance data emphasize the need to consider digestible nutrient intake as a response variable in exogenous enzyme studies.

Microbial phytase is widely used in commercial broiler diets to improve digestion of phosphorus (P) and reduce its excretion into the environment. Phytase improves the digestion of phosphorus and other nutrients including amino acids (AA). This study evaluated the effect of a novel consensus bacterial 6-phytase variant (PhyG) added to a nutrient-reduced diet without any added inorganic P on the digestibility of nutrients including P and AA in the ileum of young broilers. Effects on P retention and bone mineralization were also assessed. Compared to an unsupplemented negative control diet, PhyG improved growth performance, P retention, bone mineralization (tibia ash), digestibility of dry matter, nitrogen, gross energy, and all 17 individual AA during 5 to 15 d post-hatch, in a dose-dependent manner (dose range 0 to 1,000 phytase units [FTU] per kilogram of feed). For some AA, the increases in digestibility with PhyG at 1,000 FTU/kg were substantial (cysteine: +15.0%, threonine:+10.4%), and for all AA were equivalent to the responses produced by a nutritionally adequate positive control (unsupplemented) diet. The results demonstrate the efficacy of PhyG to improve AA digestibility alongside growth performance, P retention, and bone mineralization in young broilers.

Evaluation of the responses of broiler chickens to varying concentrations of phytate phosphorus and phytase. Ⅰ. Starter phase (day 1-11 post hatching)

Growth performance, tibia ash, apparent ileal digestibility (AID), and total tract retention (TTR) of nutrients responses of broiler chickens fed diets containing varying concentrations of phytate P (PP) and a novel consensus bacterial 6-phytase variant (PhyG) from d 1 to 11 post hatching were evaluated with 1,152 broiler chicks. Diets were a nutrient-adequate positive control diet (PC) with 2.8 g PP/kg or one of 15 nutrient-reduced negative control (NC: PC minus 88 kcal/kg ME, 0.8 g/kg dig. Lys, 2.0 g/kg available P, 1.8 g/kg Ca and 0.5 g/kg Na) diets with 3 PP (g/kg) levels, mainly from rice bran, at 2.3 (NC1), 2.8 (NC2), or 3.3 (NC3) and 5 PhyG supplementation at 0, 500, 1,000, 2,000, or 4,000 FTU/kg in a 1 + 3 × 5 factorial. All treatments had 6 replicate cages with 12 birds per cage. Despite comparable PP levels, birds fed the PC diet had greater (P ≤ 0.01) body weight (BW), feed intake (FI), tibia ash, AID of energy, AA, P, and Ca as compared with birds fed the NC2 without phytase. There was no interaction between PP and phytase for all responses. Increasing PP concentrations linearly decreased (P < 0.01) BW, FI, AID, and TTR of P and Ca. With phytase supplementation, there was a quadratic response (P < 0.05) in BW, FI, tibia ash, and a linear increase (P < 0.05) in the AID of energy, nitrogen, and all the measured AA. Increasing phytase dose from 0 to 4,000 FTU/kg increased (P < 0.01) AID of P and Ca by 88 and 18%, respectively. There was also a quadratic response (P ≤ 0.05) on TTR of P and Ca with increasing phytase dose. In conclusion, increasing levels of PP reduced growth performance and most nutrient utilization responses of broiler chickens while phytase supplementation positively impacted the responses of broiler chickens during d 1 to 11 post hatching.

Exogenous Enzymes as Zootechnical Additives in Animal Feed: A Review

Enzymes are widely used in the food industry. Their use as a supplement to the raw material for animal feed is a current research topic. Although there are several studies on the application of enzyme additives in the animal feed industry, it is necessary to search for new enzymes, as well as to utilize bioinformatics tools for the design of specific enzymes that work in certain environmental conditions and substrates. This will allow the improvement of the productive parameters in animals, reducing costs and making the processes more efficient. Technological needs have considered these catalysts as essential in many industrial sectors and research is constantly being carried out to optimize their use in those processes. This review describes the enzymes used in animal nutrition, their mode of action, their production and new sources of production as well as studies on different animal models to evaluate their effect on the productive performance intended for the production of animal feed.

Response of broiler chickens in the starter and finisher phases to 3 sources of microbial phytase

A broiler chicken study was conducted for 42 D to evaluate their responses to 3 commercially available microbial phytases. Growth performance, nutrient digestibility, and bone mineralization at days 21 and 42 posthatching were used as parameters of evaluation. The study was a randomized complete block design with 12 treatments, 8 replicate pens, and 25 birds per pen. Treatments included a positive control (PC), a negative control (NC) with crude protein (CP), nonphytate phosphorus (P), and calcium (Ca) reduced by 18, 1.5, and 1.8 g/kg, respectively; the NC + 4 levels of phytase A (250, 500, 750, 1,000 FTU/kg), 3 levels of phytase B (250, 500, 750 FTU/kg), and 3 levels of phytase C (500, 750, 1,000 FTU/kg). Broilers fed the NC diet had reduced (P < 0.05) performance and digestibility measures at days 21 and 42 relative to the PC. All phytase enzymes improved (P < 0.05) BW, gain, feed efficiency, and tibia ash weight and percent. Inclusion of phytase at the highest levels improved (P < 0.05) tibia ash weight by an average of 18.5 and 22% at days 21 and 42, respectively, over the NC. Phytase A linearly improved (P < 0.05) the apparent ileal digestibility (AID) of DM, Ca, P, copper, and sodium at day 21, and the AID of energy, nitrogen, and all amino acid (AA) digestibility at day 42 posthatching. Phytase B linearly (P < 0.05) improved BW gain and feed efficiency of birds at day 21 and quadratically improved (P < 0.05) the AID of nitrogen and all AA in birds at day 42. Supplementation of birds fed the NC with phytase C linearly improved (P < 0.05) the BW gain, feed intake, feed efficiency, and AID of DM, energy, nitrogen, all AA, and all minerals except manganese at day 42. In conclusion, all 3 phytase products improved the growth performance, nutrient and mineral digestibility, and bone mineralization of birds fed diets deficient in nitrogen, Ca, and P similar to or more than birds fed diet adequate in P and CP.

A Novel Modified Hydrated Sodium Calcium Aluminosilicate (HSCAS) Adsorbent Can Effectively Reduce T-2 Toxin-Induced Toxicity in Growth Performance, Nutrient Digestibility, Serum Biochemistry, and Small Intestinal Morphology in Chicks

The objective of this study was to evaluate the ability of a modified hydrated sodium calcium aluminosilicate (HSCAS) adsorbent to reduce the toxicity of T-2 toxin in broilers. Ninety-six one-day-old male broilers were randomly allocated into four experimental groups with four replicates of six birds each. The four groups, 1–4, received a basal diet (BD), a BD plus 6.0 mg/kg T-2 toxin, a BD plus 6.0 mg/kg T-2 toxin with 0.05% modified HSCAS adsorbent, and a BD plus 0.05% modified HSCAS adsorbent, respectively, for two weeks. Growth performance, nutrient digestibility, serum biochemistry, and small intestinal histopathology were analyzed. Compared to the control group, dietary supplementation of T-2 toxin decreased (p < 0.05) body weight gain, feed intake, and the feed conversion ratio by 11.4–31.8% during the whole experiment. It also decreased (p < 0.05) the apparent metabolic rates of crude protein, calcium, and total phosphorus by 14.9–16.1%. The alterations induced by T-2 toxin were mitigated (p < 0.05) by the supplementation of the modified HSCAS adsorbent. Meanwhile, dietary modified HSCAS adsorbent supplementation prevented (p < 0.05) increased serum aspartate aminotransferase by T-2 toxin at d 14. It also prevented (p < 0.05) T-2 toxin-induced morphological changes and damage in the duodenum, jejunum, and ileum of broilers. However, dietary supplementation of the modified HSCAS adsorbent alone did not affect (p > 0.05) any of these variables. In conclusion, these findings indicate that the modified HSCAS adsorbent could be used against T-2 toxin-induced toxicity in growth performance, nutrient digestibility, and hepatic and small intestinal injuries in chicks.

Current and Future Applications of Phytases in Poultry Industry: A Critical Review

Phytases are enzymes that initiate the removal of phosphate from phytate. This enzyme has been widely utilized in animal feeding especially in the poultry industry to enhance phosphorus intake and minimize environmental pollution. Phytases are widely distributed in microbial, plants and animals. Supplementations of phytase into the diets of poultry have great impact to the improvement of poultry immune systems and increase bird weight. In addition to that, phytase are able to improve both quantity and quality of eggs, egg mass and egg shell quality. This review covers the classifications and distribution of phytases in different biofactoris. In addition, it shed more light on the recent trends of application and beneficial impact in poultry farming.

Supplementation of Buttiauxella sp. 6-phytase to commercial laying hen diets with reduced nutrient density on productive performance and egg quality

A study was conducted to evaluate productive performance in laying hens fed diets with reduced nutrient density based on the nutritional contribution of a Buttiauxella phytase in laying-hen diets from 21-57 weeks of age. A commercial laying hen diet was offered ad libitum to the 480 ISA Brown laying hens from 18-21 weeks of age. From 21 weeks onwards, the hens received one of four dietary treatments: a positive control (PC) diet, a down specified diet (DS1) + phytase at 300 FTU/kg, a second down-specified diet (DS2) + phytase at 600 FTU/kg and a third test diet formulated as per DS1 + phytase at 1,200 FTU/kg feed. The PC was formulated based on ISA breeder recommendations. DS1 was formulated with reduction of 0.149% available P, 0.134% Ca, 55 kcal/kg AME, 0.33% CP, digestible amino acids (up to 0.015%) and 0.013% Na based on the contribution of Buttiauxella phytase at 300 FTU/kg. DS2 was formulated with reduction of 0.177% available P, 0.159% Ca, 60 kcal/kg AME, 0.61% CP, digestible amino acids (up to 0.028%) and 0.02% Na based on the contribution of Buttiauxella phytase at 600 FTU/kg. Every dietary treatment was fed to 12 cages containing 10 hens each. The trial treatments did not include a full, DS negative control, as ethical considerations regarding birds' welfare when feeding such diets over such an extended period of time did not permit this. No significant differences were seen in hen-day egg production, feed intake, egg weight, feed to egg mass ratio, shell, yolk or albumen proportion, unsaleable eggs or shell breaking strength in laying hens fed the PC diet or the DS diets with added phytase. Yolk colour increased significantly with phytase supplementation. Supplementing the DS1 diet with 300 FTU and the DS2 diet with 600 FTU resulted in non-significant differences in tibia ash, Ca and P, compared to the PC diet. The data from this study indicated that applying the nutrient contributions for Buttiauxella phytase at 300 and 600 FTU/kg maintained the egg production, BW and egg quality parameters compared to PC. The best economic efficiency value during the whole experimental period was recorded with phytase at 600 FTU/kg when full matrix values are used. When commercial diets are formulated based on ISA breeder recommendations, lowering diet nutrient density while supplementing with phytase reduced the overall diet cost, which should contribute to the profitability of egg production.

[Prediction of protein thermostability from their primary structure: the current state and development factors]

The construction of proteins and peptides with desired properties, including resistance to high temperatures, as well as optimization of their amino acid composition, is an important and complex task, which attracts much attention in various branches of the basic sciences, and also in biomedicine and biotechnology. This raises the question: what method is more relevant for the at the pilot stage of research in order to estimate the influence of the planned amino acid substitutions on the thermostability of the resultant protein construct? In this brief review we have classified existing basic practical and theoretical approaches used in studies and predicting the thermal stability of native and recombinant polypeptides. Particular attention has been paid to the predictive potential of statistical methods for studying the thermodynamic parameters of the primary protein structure and prospects of their use.

Effectiveness of exogenous microbial phytase in improving the bioavailabilities of phosphorus and other nutrients in maize-soya-bean meal diets for broilers

A 3-week feeding trial using 300 1-day-old male broiler chicks was conducted to evaluate the effects of adding three levels of a microbial phytase (Finnfeed phytase; 250, 500 and 1000 U per kg diet) to a maize-soya-bean-meal diet containing 3·0 g/kg non-phytate phosphorus and 8·0 g/kg calcium. A diet containing 4·0 g/kg non-phytate phosphorus and 9·0 g/kg calcium served as the positive control. The responses were evaluated in terms of broiler performance, toe ash contents, ileal phytate degradation, ileal digestibility of nitrogen, amino acids, phosphorus, starch and fat, apparent metabolizable energy, apparent ileal digestible energy, and apparent retention of phosphorus and nitrogen. The addition of 500 U phytase per kg diet to the phosphorus-deficient maize-soya-bean-meal diet improved the performance and toe ash contents of broilers to equal those given the positive control diet. Ileal phytate degradation data provided direct evidence to the efficacy of phytase in hydrolysing the phytic acid. Addition of 500 U phytase per kg to the maize-soya-bean-meal diet which contained 3·0 g phytate-phosphorus per kg resulted in more than doubling of phytate degradation from 0·218 to 0·481. Supplemental phytase improved ileal digestibility of nitrogen, amino acids, starch and lipids, with these improvements being eventually reflected in enhancements in ileal digestible energy and apparent metabolizable energy.

Energy values of canola meal, cottonseed meal, bakery meal, and peanut flour meal for broiler chickens determined using the regression method

The energy values of canola meal (CM), cottonseed meal (CSM), bakery meal (BM), and peanut flour meal (PFM) for broiler chickens were determined in 2 experiments with Ross 708 broiler chickens from d 21 to 28 posthatch. The birds were fed a standard broiler starter diet from d 0 to 21 posthatch. In each experiment, 320 birds were grouped by weight into 8 blocks of 5 cages with 8 birds per cage and assigned to 5 diets. Each experiment used a corn-soybean meal reference diet and 4 test diets in which test ingredients partly replaced the energy sources in the reference diet. The test diets in Exp. 1 consisted of 125 g CM, 250 g CM, 100 g CSM, or 200 g CSM/kg. In Exp. 2, the test diets consisted of 200 g BM, 400 g BM, 100 g PFM, or 200 g PFM/kg. The ileal digestible energy (IDE), metabolizable energy (ME), and nitrogen-corrected metabolizable energy (ME_n) of all the test ingredients were determined by the regression method. The DM of CM, CSM, BM and PFM were 883, 878, 878, and 964 g/kg, respectively and the respective gross energies (GE) were 4,143, 4,237, 4,060, and 5,783 kcal/kg DM. In Exp. 1, the IDE were 2,132 and 2,197 kcal/kg DM for CM and CSM, respectively. The ME were 2,286 and 2,568 kcal/kg DM for CM and CSM, respectively. The ME_n were 1,931 kcal/kg DM for CM and 2,078 kcal/ kg DM for CSM. In Exp. 2, IDE values were 3,412 kcal/kg DM for BM and 4,801 kcal/kg DM for PFM; ME values were 3,176 and 4,601 kcal/kg DM for BM and PFM, respectively, and the ME_n values were 3,093 kcal/kg DM for BM and 4,112 kcal/kg DM for PFM. In conclusion, the current study showed that chickens can utilize a considerable amount of energy from these 4 ingredients, and also provided the energy values of CM, CSM, BM and PFM for broiler chickens.

Evaluation of increasing levels of a microbial phytase in phosphorus deficient broiler diets via live broiler performance, tibia bone ash, apparent metabolizable energy, and amino acid digestibility

The objective was to investigate increasing concentrations of an evolved microbial phytase on male broiler performance, tibia bone ash, AME, and amino acid digestibility when fed diets deficient in available phosphorus (aP). Experiment 1 evaluated the effects of phytase during a 21 d battery cage study and Experiment 2 was a 42 d grow-out. Experiment 1 included six treatments; negative control (NC) with an aP level of 0.23% (starter) and 0.19% (grower), two positive controls (PC) consisting of an additional 0.12% and 0.22% aP (PC 1 and PC 2), and the NC supplemented with three levels of phytase (250, 500, and 2,000 U/kg). The NC diet reduced (P < 0.05) FC, BW, and bone ash. Phytase increased (P < 0.05) BW with 2,000 U/kg phytase yielding similar results to the PC2, and improved FCR and increased bone ash was observed at all phytase levels. Amino acid digestibility coefficients were increased (P < 0.05) with phytase at 250 U/kg. Phytase at all rates increased (P < 0.05) AME to levels similar level as PC diets. Linear regression analysis indicated average P equivalency values for BW and bone ash of 0.137, 0.147, and 0.226 for phytase inclusion of 250, 500, and 2000 U/kg, respectively. Experiment 2 included a PC consisting of 0.45%, 0.41%, and 0.38% aP for the starter, grower, and finisher, respectively; NC with reduced aP of 0.17%; and phytase at 500 and 2,000 U/kg. Phytase increased BW (P < 0.05) compared to the NC as 2,000 U/kg phytase resulted in further BW increases compared to the PC (starter and grower). Phytase improved FCR to levels comparable to the PC, with supplementation at 2,000 U/kg resulting in improvements beyond the PC in the starter phase. Amino acid digestibility coefficients were increased with phytase at 2,000 U/kg to levels comparable to that of the PC. These data confirm that the inclusion of phytase improves broiler performance and bone mineralization in aP reduced diets and levels beyond the traditional 500 U/kg can result in further improvements.

Comparison of 3 phytases on energy utilization of a nutritionally marginal wheat-soybean meal broiler diet

The net energy (NE) value may be a better measure than apparent metabolizable energy (ME) of the effect of supplemental phytase on energy utilization in broilers. The present study was conducted to assess the impact of 3 microbial phytases supplemented at an unconventionally high level (1,000 FTU/kg feed) on performance and NE of broilers using the indirect calorimetric method (IC). Four treatments included: 1) Control, formulated to be deficient in ME (12.35 MJ/kg in the starter diet; 12.56 MJ/kg in the grower diet), calcium (0.72% in the starter diet; 0.60% in the grower diet), and available phosphorus (0.25% in the starter diet; 0.20% in the grower diet); 2) control + intrinsically thermostable phytase A; 3) control + intrinsically thermostable phytase B; and 4) control + coated phytase C. A completely randomized design was employed. A total of 384 male broiler chicks were used, and each treatment had 6 replicates with 16 birds per replicate. The birds were reared until d 21 in floor pens with hardwood shavings. Thirty-two birds (8 birds per treatment) were randomly selected to determine heat production and NE (from 25-28 d) following a 3-d acclimatization in the respiratory chambers. Performance results at d 21 showed that supplementation with either of the 3 phytases improved body weight (P < 0.001) and feed intake (P < 0.05), and increased the relative weights of tibia ash (P < 0.05) and toe ash (P < 0.01). Phytases A and B increased the NE value of the diet (P < 0.05). It may be concluded that the negative effects imposed by calcium and available phosphorus down-specification can be compensated by phytase supplementation in general, and intrinsically thermostable phytases improve the ME and NE value. However, phytase did not reduce heat production, heat increment, or increase NE:ME in birds.

The efficacy of a new 6-phytase obtained from Buttiauxella spp. expressed in Trichoderma reesei on digestibility of amino acids, energy, and nutrients in pigs fed a diet based on corn, soybean meal, wheat middlings, and corn distillers' dried grains with solubles

Sixteen cannulated pigs were used to evaluate the effect of a new 6-phytase derived from Buttiauxella spp. and expressed in Trichoderma reesei on apparent ileal digestibility (AID) of AA and apparent total tract digestibility (ATTD) of DM, N, Ca, P, Na, Mg, K, Cl, and energy. Pigs were fed 4 diets for 2 periods in a crossover design. Within each period, there were 4 blocks of 4 pigs per block with each diet represented within each block. The average initial BW in periods 1 and 2 were 22 and 30 kg, respectively. Each period lasted 9 d with fecal collection on d 5 and 6 and a 12-h ileal digesta collection on d 7, 8, and 9. Pigs received a daily feed allowance of approximately 4.5% of their BW. The experimental diets were based on corn, soybean meal, wheat middlings, and corn distillers dried grain with solubles. Phytase was added at 0; 500; 1,000; or 2,000 phytase units/kg of diet to a basal diet that contained 205, 15, 5.4, and 10 g of CP, Lys, total P (1.6 g of nonphytate P), and Ca/kg diet, respectively. The addition of phytase improved (P < 0.05) AID of DM, N, Ca, and P. Increasing phytase supplementation linearly and quadratically increased (P < 0.05) AID of P and Ca, respectively, with AID of Ca showing a tendency for a linear increase (P = 0.053). Phytase supplementation of the basal diet improved (P < 0.05) AID of P from 46 to 62%. Phytase supplementation increased (P < 0.05) ATTD of DM, N, Ca, P, Mg, K, and energy. Contrasts showed that phytase supplementation of the basal diet increased (P < 0.05) AID for 8 indispensable AA (Arg, His, Ile, Leu, Lys, Phe, Thr, and Val), 6 dispensable AA (Ala, Asp, Cys, Glu, Ser, and Tyr), as well as for total AA. Furthermore, phytase supplementation to the basal diet showed a tendency (P < 0.10) to increase ileal digestibility of Gly. Ileal digestibility of Met, Trp, and Pro were not affected by phytase supplementation. Increasing the level of phytase supplementation resulted in linear increases (P < 0.05) in AID of 6 indispensable AA (Arg, Ile, Leu, Lys, Phe, and Val) and 1 dispensable AA (Asp) with 4 AA (His, Cys, Glu, and Tyr) showing a tendency for linear increase (P < 0.10) in AID of AA. The results from this study showed that in addition to increasing P and Ca utilization, the new Buttiauxella 6-phytase expressed in Trichoderma reesei enhanced ileal digestibility of N and several AA in growing pigs in a dose-dependent manner.

Extra-phosphoric effects of phytase with and without xylanase in corn-soybean meal-based diets fed to broilers

Two experiments were conducted to evaluate the extra-phosphoric effects of phytase on amino acid (AA) and energy digestibility (experiments 1 and 2) and growth performance (experiment 2) of broilers fed diets adequate in Ca and nonphytate P supplemented with xylanase. Ross × Ross 708 broiler chicks (864 males in experiment 1 and 1,152 females in experiment 2) were randomly distributed into battery cages (6 replicate cages per treatment) with 12 birds per cage at 1 d of age. In both experiments, factorial arrangements of treatments were evaluated consisting of 6 phytase [0, 1,000, 2,000, 4,000, 8,000, or 16,000 phytase units (FTU)/kg] and 2 xylanase [0 or 16,000 birch xylan units (BXU)/kg] concentrations in experiment 1 and 4 phytase (0, 500, 1,000 or 2,000 FTU/kg) and 4 xylanase (0, 8,000, 16,000, or 32,000 BXU/kg) concentrations in experiment 2. Treatments were provided from 27 to 32 d of age in experiment 1 and from 1 to 32 d of age in experiment 2. Digesta contents of the terminal ileum were collected at 32 d of age (experiment 1 and 2), and growth performance was measured at 1, 14, and 25 d of age in experiment 2. There was no interaction of phytase and xylanase; only main effects of phytase were observed. In experiment 1, broilers fed diets supplemented with phytase at 1,000 FTU/kg had increased (P < 0.05) apparent ileal digestibility (AID) of all AA with the exception of Ala and Met. Diets fed to broilers supplemented with higher concentrations of phytase did not further increase AID of any AA (P > 0.05) above the addition of 1,000 FTU/kg of phytase. Phytase supplementation did not affect ileal digestible energy (P > 0.05). For all variables measured, significant log-linear or log-quadratic effects of phytase (P > 0.05) were not observed. In contrast, broilers fed diets supplemented with phytase in experiment 2 exhibited log-linear (P < 0.05) increases in AID of AA but not apparent ileal digestible energy. However, supplementation with 2,000 FTU/kg of phytase increased (P = 0.05) ileal digestible energy by 36 kcal/kg compared with the basal diet. Broilers fed diets with 1,000 FTU/kg of phytase had improved growth performance (P < 0.05) in comparison with broilers fed diets containing 0 or 500 FTU/kg of phytase. The addition of 500 FTU/kg of phytase in diets fed to broilers did not affect ileal digestibility or growth performance (P > 0.05). Data obtained from these experiments demonstrated extra-phosphoric effects in broilers fed diets supplemented with 1,000 FTU/kg of phytase and diminishing returns with higher concentrations.

Effect of rice polishing and phytase supplementation in diets on productive behavior of broilers

The addition of rice polishing (RP) and phytase enzyme to poultry diets was tested on 200 1-day-old broilers weighing 42 g. Birds were assigned to a completely random design with a 2 × 2 factorial arrangement with four treatments and five repetitions of ten birds each. The factors evaluated were RP level (0 and 15%) and phytase (0 and 150 g/ton). The trial was divided in two phases of 21 days each (42 days total). In phase 1, no treatment effects were observed (P>0.10) on poultry productive behavior. In the second phase (21 to 42 days) and on the total trial (1 to 42 days), there were no effects of the treatments on weight gain or feed intake (P>0.10). Feed conversion was affected by RP (P<0.01) but not by phytase addition (P>0.10). In conclusion, phytase did not affect broiler production with or without RP. Addition of 15 % RP in poultry diets represents an alternative to reduce feed costs.

Effects of freeze-dried Mitsuokella jalaludinii culture and Natuphos(®) phytase supplementation on the performance and nutrient utilisation of broiler chickens

BACKGROUND

Phytate-bound phosphorus (P) in poultry diets is poorly available to chickens. Hence exogenous phytase is often added to their diets. Mitsuokella jalaludinii is a rumen bacterial species that produces high phytase activity. In this study the effects of freeze-dried active M. jalaludinii culture (FD-AMJC) and Natuphos(®) phytase (phytase N) supplementations on the growth performance and nutrient utilisation of broiler chickens fed a low-available P (aP) diet were evaluated.

RESULTS

Supplementation of FD-AMJC or phytase N to the low-aP diet improved the feed intake, feed conversion rate, body weight gain, dry matter (DM) digestibility and P, Ca and Mn retention, increased the tibia bone ash content, Ca and P concentrations in tibia DM and P and Zn concentrations in plasma and reduced the P excretion of broiler chickens. However, the feed conversion rate, P and Ca retention, DM digestibility and reduction of P excretion were better with FD-AMJC than phytase N supplementation. Supplementation of FD-AMJC to the low-aP diet also improved the apparent metabolisable energy value of the diet, Cu and Zn retention and crude protein digestibility, but phytase N supplementation did not.

CONCLUSION

FD-AMJC supplementation was more efficient in improving nutrient utilisation and reducing P excretion in chickens than phytase N supplementation.

BOARD-INVITED REVIEW: opportunities and challenges in using exogenous enzymes to improve nonruminant animal production

Diets fed to nonruminant animals are composed mainly of feed ingredients of plant origin. A variety of antinutritional factors such as phytin, nonstarch polysaccharides, and protease inhibitors may be present in these feed ingredients, which could limit nutrients that may be utilized by animals fed such diets. The primary nutrient utilization-limiting effect of phytin arises from the binding of 6 phosphate groups, thus making the P unavailable to the animal. The negative charges allow for formation of insoluble phytin-metal complexes with many divalent cations. Furthermore, phytin and protein can form binary complexes through electrostatic links of its charged phosphate groups with either the free amino group on AA on proteins or via formation of ternary complexes of phytin, Ca(2+), and protein. The form and extent of de novo formation of binary and ternary complexes of phytin and protein are likely to be important variables that influence the effectiveness of nutrient hydrolysis in plant-based diets. Nonstarch polysacharides reduce effective energy and nutrient utilization by nonruminant animals because of a lack of the enzymes needed for breaking down the complex cell wall structure that encapsulate other nutrients. Enzymes are used in nonruminant animal production to promote growth and efficiency of nutrient utilization and reduce nutrient excretion. The enzymes used include those that target phytin and nonstarch polysaccharides. Phytase improves growth and enhances P utilization, but positive effects on other nutrients are not always observed. Nonstarch polysaccharide-hydrolyzing enzymes are less consistent in their effects on growth and nutrient utilization, although they show promise and it is imperative to closely match both types and amounts of nonstarch polysaccharides with appropriate enzyme for beneficial effects. When used together with phytase, nonstarch polysaccharide-hydrolyzing enzymes may increase the accessibility of phytase to phytin encapsulated in cell walls. The future of enzymes in nonruminant animal production is promising and will likely include an understanding of the role of enzyme supplementation in promoting health as well as how enzymes may modulate gene functions. This review is an attempt to summarize current thinking in this area, provide some clarity in nomenclature and mechanisms, and suggest opportunities for expanded exploitation of this unique biotechnology.

Phytase supplemented poultry diets affect soluble phosphorus and nitrogen in manure and manure-amended soil

Understanding P and N dynamics in manure-amended soil is essential for estimating the environmental impact of manure utilization in land applications. A laboratory incubation study was conducted to assess, (i) the effect of feeding a standard Australian commercial diet, and diets modified with phytase supplementation and reduced nonphytase phosphorus (NPP), on the concentrations of P and N (total and soluble) in the manure derived from layer hens (Gallus domesticus L.), and (ii) the change in water-soluble phoshorus (P(WSP)) and mineral N (NH(4)-N and NO(3)-N) when used as a soil amendment, applied at rates equivalent to 200 kg ha(-1) (200N) and 400 kg ha(-1) (400N). Phytase supplementation increased %P(WSP) by 8 to 12% in the manures, regardless of the levels of NPP in the diets, and in the manure-amended soils by 27 to 30% at the 200N application rate, and up to 54% at the 400N rate. Phytase significantly (P < 0.05) reduced total nitrogen (TN) content (by 12-31%) of the manures but generally produced greater nitrate accumulation in the manure-amended soils. Net nitrification, which commenced 4 wk after incubation, was accompanied by a simultaneous decrease in soil pH (by one pH unit) and a concomitant decline in %P(WSP). The decline in %P(WSP) was primarily attributed to P retention by the soil as it became more acidic. This study suggests that phytase addition not only reduces manure total N content, and increases water-soluble P, but its effects on manure total phosphorus (TP) and 2 mol L(-1) KCl extractable mineral N is influenced by the NPP level in the diet.

Utilização de nutrientes em frangos alimentados com dietas suplementadas com fitase e níveis reduzidos de fósforo não-fítico

Avaliaram-se a digestibilidade ileal, retenção de nutrientes e valores de energia metabolizável aparente (EMA) de dietas suplementadas com fitase e níveis reduzidos de fósforo não-fítico (FNF) para frangos de corte. Foram utilizados 330 pintos machos em delineamento em blocos ao acaso e esquema fatorial 2 x 3 com dois níveis de fitase (0 e 25U/kg) e três níveis de FNF (100, 85 e 70% das exigências da ave), totalizando seis tratamentos com cinco repetições de 11 aves cada. Não houve efeito da interação FNF vs fitase e dos níveis de FNF ou fitase sobre a retenção de matéria seca e de fósforo, e a interação FNF vs fitase foi significativa para retenção de proteína bruta e coeficiente de digestibilidade ileal da matéria seca. A suplementação com fitase, independente dos níveis de FNF, melhorou o coeficiente digestibilidade ileal da proteína bruta, do cálcio e do fósforo. A retenção de cálcio e a redução dos níveis de FNF diminuíam a metabolização da energia bruta das dietas com 85 e 70% das exigências de FNF. Dietas com nível de 70% das exigências de FNF, suplementadas com fitase, podem ser usadas para frangos de corte sem prejuízos à digestibilidade ileal e retenção da matéria seca, proteína bruta, cálcio e fósforo e à metabolização da energia bruta.

Energy utilization and growth performance of broilers receiving diets supplemented with enzymes containing carbohydrase or phytase activity individually or in combination

Energy utilization in broilers as influenced by supplementation of enzymes containing phytase or carbohydrase activities was investigated. Day-old male broilers (480) were allocated to four slaughter groups, thirty broilers in the initial slaughter group and 150 broilers in each of the final slaughter groups on days 7, 14 and 21. Broilers in each of the final slaughter groups were allocated to five treatments in a randomized complete block design, each treatment had six replicate cages of five broilers per replicate cage. The diets were maize–soyabean based with wheat as a source of NSP. The treatments were: (1) positive control that met nutrient requirements of the day-old broiler chick; (2) negative control (NC) deficient in metabolizable energy and P; (3) NC plus phytase added at 1000 FTU/kg; (4) NC plus cocktail of xylanase, amylase and protease (XAP); and (5) NC plus phytase and XAP. Gain and gain:food were depressed (P < 0·05) in the NC diet. Phytase improved (P < 0·05) gain at all ages and gain:food at days 0–14 and days 0–21. There was improvement (P < 0·01) in net energy for production, energy retained as fat and protein from days 0 to 14 and from days 0 to 21 in phytase-supplemented diet compared with the NC diet. Net energy for production was more highly correlated with performance criteria than metabolizable energy and may be a more sensitive energy utilization response criterion to use in evaluating broiler response to enzyme supplementation.

Evolving enzyme technology: impact on commercial poultry nutrition

The use of exogenous enzymes to improve the nutritional value of poultry diets is a relatively new concept. The technology is rapidly evolving, with new enzymes, enzyme combinations, and novel applications being developed as rapidly as regulatory restrictions will allow. Most researchers in the field of poultry nutrition would consider phytase to be the last significant leap forward in terms of enzyme use in the animal feed industry. However, there is a great deal of ongoing research into the next generation of enzymes with a focus on ingredient quality, predictability of response via least-square models, improvements in food safety, effect of bird age, effect of various side activities and enzyme dose, maximisation of net income and reduction in environmental pollution. It is the purpose of the present review article to summarise the current research in the area of feed enzymes for poultry and to speculate on future applications of enzymes and new enzyme technologies that may be of value to the industry in the coming years.

Phytate and phytase: consequences for protein utilisation

The excretion of large amounts of P in effluent from intensive pig and poultry units is indicative of the poor availability of phytate-bound P in plant-derived feed ingredients. This environmental problem prompted the development and acceptance of microbial phytase feed enzymes for single-stomached animals. Their introduction led to an increasing recognition that phytate may have adverse effects on protein utilisation in addition to P. Consequently, the nutritional relevance of protein–phytate interactions for pigs and poultry is considered in the present review. Since the current understanding of the effects of protein–phytate interactions comes mainly from responses obtained to added phytase, literature on the influence of microbial phytases on amino acid digestibility and utilisation is summarised, followed by a discussion of possible mechanisms contributing to the negative effects of phytate. However, the rationale for the protein responses to added phytase remains largely speculative, and several modes of action are probably involved. It may be that the release of protein from protein–phytate complexes occurring naturally in feed ingredients, the prevention of formation of binary and ternary protein–phytate complexes within the gut, the alleviation of the negative impact of phytate on digestive enzymes and the reduction in endogenous amino acid losses are all contributing factors. A better understanding of the mechanisms of protein–phytate interactions and the modes of action of exogenous phytase enzymes is clearly desirable. Studies are also needed to identify and quantify the factors that contribute to the variable amino acid responses to added phytase. It appears that the relative solubilities of phytate salts and proteins from different feed ingredients and their effects on the extent of protein–phytate complex formation, coupled with variations in the effectiveness of phytase in different dietary contexts, may be the major factors responsible.

Supplementation of corn-soy-based diets with an Eschericia coli-derived phytase: effects on broiler chick performance and the digestibility of amino acids and metabolizability of minerals and energy

The effect of the supplementation of diets containing low available P concentrations with low and supra-activities of an Eschericia coli 6-phytase was assessed using growing broiler chicks. A total of 384 female Ross broiler chicks were weighed at d 1 of life and assigned to 1 of 8 experimental treatments. There were 12 replicate cages with 4 chicks per cage, and the diets were fed from d 1 of life for a period of 16 d. A positive control diet (5 g/kg of available P) and a negative control diet (3 g/kg of available P) were used, and 6 more diets were manufactured by supplementing the negative control diet with 150, 300, 600, 1,200, 2,400, and 24,000 U/kg of exogenous phytase. Body weight gain and feed conversion ratios were determined, as were nutrient digestibility coefficients and toe ash values. Birds fed the negative control diet had lower (P < 0.05) weight gains than those fed the positive control diet. The addition of exogenous phytase above 150 U/kg improved (P < 0.05) weight gain, toe ash percentage, and nutrient utilization of the birds fed the negative control diet. Furthermore, the 24,000 U/kg of diet improved (P < 0.05) toe ash percentage and the utilization of several nutrients beyond that of the lower doses of phytase. It can be concluded that the supplementation of diets containing 3 g/kg of available P with exogenous phytase can improve the performance of chicks to that of birds fed a diet containing 5 g/kg of available P. In addition, the use of high doses of phytase (> 1,000 U/kg of diet) can improve nutrient availability in poultry diets beyond that of diets containing lower (< 1,000 U/kg) phytase activities. These results may be mediated partially by reduced endogenous loss as well as an increase in the availability of dietary nutrients as indicated by improvements in digestibility coefficients.

Influence of an Escherichia coli-derived phytase on nutrient utilization in broiler starters fed diets containing varying concentrations of phytic acid

The influence of an Escherichia coli-derived phytase, on nutrient utilization was investigated in broilers fed starter diets containing different concentrations of phytate. The study was conducted as a 3 x 4 factorial arrangement of treatments with 3 concentrations of phytic acid (10.4, 11.8, and 13.6 g/kg; equivalent to 2.8, 3.3, and 3.8 g of phytate P/kg) and phytase (0, 500, 750, and 1,000 FTU/kg). One unit of phytase (FTU) is defined as the quantity of enzyme that releases 1 micromol of inorganic phosphorus/min from 0.00015 mol/L of sodium phytate at pH 5.5 at 37 degrees C. The dietary phytic acid concentrations were manipulated by the inclusion of rice bran. Increasing dietary concentrations of phytic acid resulted in reductions (P < 0.01) in AME. Phytase additions tended to increase AME (P = 0.07), regardless of dietary phytate concentrations. Apparent ileal digestibility coefficients of protein and most amino acids were influenced by phytate (P < 0.05 to 0.001) and phytase (P < 0.001). Phytase improved ileal protein and amino acid digestibility at all phytate concentrations, but the trend in responses to increasing phytase additions was different at different phytate concentrations as shown by significant phytate x phytase interactions (P < 0.01 to 0.001). At the lowest phytate concentration, the ileal digestibility coefficients increased with increasing phytase supplementation. At the medium and high phytate concentrations, the greatest responses were observed at 500 FTU/kg of phytase, with little improvement attributable to further additions. Ileal digestibility of P was lowered (P < 0.01) by increasing phytate concentrations and increased (P < 0.001) with increasing additions of phytase. A significant phytate x phytase interaction (P < 0.05) was also observed, where the improvements in P absorption with added phytase were found to be greater at high phytate concentrations. These data demonstrate the anti-nutritive effects of phytic acid and the potential of microbial phytase to improve energy utilization and the availability of P and amino acids in broilers fed starter diets.

Interaction between protein, phytate, and microbial phytase. In vitro studies

The interaction between protein and phytate was investigated in vitro using proteins extracted from five common feedstuffs and from casein. The appearance of naturally present soluble protein-phytate complexes in the feedstuffs, the formation of complexes at different pHs, and the degradation of these complexes by pepsin and/or phytase were studied. Complexes of soluble proteins and phytate in the extracts appeared in small amounts only, with the possible exception of rice pollards. Most proteins dissolved almost completely at pH 2, but not after addition of phytate. Phytase prevented precipitation of protein with phytate. Pepsin could release protein from a precipitate, but the rate of release was increased by phytase. Protein was released faster from a protein-phytate complex when phytase was added, but phytase did not hydrolyze protein. Protein was released from the complex and degraded when both pepsin and phytase were added. It appears that protein-phytate complexes are mainly formed at low pH, as occurs in the stomach of animals. Phytase prevented the formation of the complexes and aided in dissolving them at a faster rate. This might positively affect protein digestibility in animals.

A Study on the Interaction of Xylanase and Phytase Enzymes in Wheat-Based Diets Fed to Commercial White and Brown Egg Laying Hens

A trial was conducted to investigate potential interactions between phytase and xylanase enzymes in wheat-based laying diets. Hens (480 ISA-White and 480 ISA-Brown) were distributed into 160 experimental units and fed one of 10 diets containing 75 to 77% wheat from 33 to 64 wk of age with a diet change at 49 wk. Two diets were adequate in P content (0.3 and 0.25% available P in the 2 phases) with or without xylanase (0 or 2,000 U/kg; Avizyme 2300, Danisco Animal Nutrition, Marlborough, Wiltshire, United Kingdom), and 8 diets had reduced P (0.2 and 0.15% available P) with or without xylanase and phytase (0, 300, 500, and 700 ppu/kg; Phyzyme 5000G, Danisco Animal Nutrition). Egg production was higher for ISA-Brown than for ISA-White hens, and ISA-Brown hens were larger. Eggs from ISA-Brown hens had lower albumen height; higher egg, shell, and albumen weights; and lower yolk weight than those from ISA-White hens. Egg production was not affected by the diet. In P-reduced diets without xylanase, phytase significantly increased BW gain in the first period with no change in feed intake or feed efficiency. In P-adequate diets, xylanase increased egg and albumen weight and albumen height. In P-reduced diets with xylanase, increasing levels of phytase increased egg and albumen weight. This trial demonstrated no negative interactions between these enzymes for production traits and no interactions between the diet and strain of hen. These data suggest that poultry producers can use these enzymes individually or together in feed for the Brown and White egg layers used in this study without concern for the strain of hen.

Improvements in Nitrogen-Corrected Apparent Metabolizable Energy of Peanut Meal in Response to Phytase Supplementation

A study was conducted to investigate the effect of phytase on the AMEn of peanut meal. One hundred twenty Ross x Ross broiler chicks of mixed sex were fed one of 4 experimental diets from 5 to 15 d of age. Diets used were Diet 1, a low P corn-soybean based basal diet; Diet 2, a 50% basal + 50% peanut meal diet; Diet 3, the basal diet supplemented with 24,000 phytase units (FTU) of Natuphos 5000 phytase/kg; and Diet 4, a phytase-supplemented 50% basal + 50% peanut meal diet. Chromic oxide was added to the basal diet at 0.1% as an indigestible marker. Apparent metabolizable energy was determined by substituting peanut meal at the expense of the basal diet. Other parameters measured included the phytate content of the diets as well as phytate P disappearance. Phytase significantly improved phytate P disappearance for both the corn and soybean meal basal diet (23.8 to 93.7%) as well as the 50% basal + 50% peanut meal diet (16.7 to 89.5%). Phytase increased the AMEn of peanut meal on a DM basis by approximately 9%, from 3,209 to 3,559 kcal/kg.

Comparison of Natuphos and Phyzyme as phytase sources for commercial layers fed corn-soy diet

The objective of this experiment was to compare the effects of 2 sources of phytase on performance of commercial Leghorns fed corn-soy diets. Seven diets were fed to Hy-line W-36 hens (n = 840; 8 replicates of 15 hens per treatment) from 21 to 33 wk of age. The treatments consisted of a control diet containing 0.38% nonphytate P (NPP) and a 2 x 3 factorial arrangement of 2 dietary NPP concentrations (0.11 and 0.26%) with 2 phytase sources [Natuphos (BASF, Mt. Olive, NJ) and Phyzyme (Danisco Animal Nutrition, Carol Stream, IL)] and without phytase. Dietary NPP had significant effects on feed intake, NPP intake, total P intake, egg production, egg weight, egg mass, egg specific gravity, and excreta P. The addition of Phyzyme or Natuphos significantly increased egg production and egg mass of hens fed the P-deficient diet (0.11% NPP) to levels that were similar to hens fed the control diet containing 0.38% NPP. Feed intake of hens fed the diets supplemented with Phyzyme or Natuphos was significantly less than that of hens fed the control diet containing 0.38% NPP. Phyzyme or Natuphos supplementation in the diets containing 0.11% NPP had significantly reduced excreta P of the control diet (approximately 58 and 54%, respectively) with no adverse effect on egg production and egg mass. There were no significant differences in feed intake, NPP intake, total P intake, egg production, egg weight, egg mass, feed conversion, egg specific gravity, mortality, BW, and excreta P between the diets supplemented with Natuphos and the diets supplemented with Phyzyme. In conclusion, Phyzyme had the same positive effects on performance of commercial Leghorns fed corn-soy diets as Natuphos.

Effects of calcium and nonphytate phosphorus concentrations on phytase efficacy in broiler chicks

Phytase supplementation over a range of different levels of dietary Ca and nonphytate phosphorus (NPP) was investigated by comparing surface response curves from regression equations generated with (experiment 1) and without (experiment 2) phytase using various performance and bone quality parameters. Cobb x Cobb broiler chicks were raised from 0 to 16 d in 2 experiments using corn-soybean meal based diets. Experiment 1 used a 4 x 4 factorial arrangement with diets formulated to contain combinations of 4 levels of Ca: 0.38, 0.58, 0.78, and 0.98% and 4 levels of NPP: 0.2, 0.3, 0.4, and 0.5%. Experiment 2 used a composite rotatable design in which rations were formulated to contain dietary Ca levels of 0.38, 0.47, 0.68, 0.89, and 0.98% and NPP levels of 0.20, 0.24, 0.35, 0.46, and 0.50%. An extra point was included in the design to contain the lowest Ca and lowest NPP levels (0.38% Ca and 0.20% NPP). All combinations of Ca and NPP were fed with 657 phytase units/kg Natuphos 5000 phytase, plus 4 combinations (0.38% Ca and 0.20% NPP, 0.47% Ca and 0.24% NPP, 0.68% Ca and 0.35% NPP, and 0.89% Ca and 0.46% NPP) were fed without phytase to determine the suitability of comparing multiple regression response surfaces for particular variables among experiments. Comparison of surfaces, with and without phytase, showed that growth and bone quality responses to phytase were greatest at low NPP levels and high Ca levels, and these decreased when the Ca level was reduced or when the NPP level was increased. A third experiment confirmed that phytase elicits a greater response at higher Ca levels and lower NPP levels (0.86% Ca and 0.20% NPP) versus low Ca levels and low NPP levels (0.47% Ca and 0.24% NPP). The data demonstrated why it is impossible to determine a single NPP equivalency value for phytase supplements.

Efficacy of an evolved Escherichia coli phytase in diets of broiler chicks

An evolved Escherichia coli-derived phytase was evaluated for its efficacy in improving growth performance and nutrient utilization of broiler chicks. One hundred forty-four 7-d-old male broiler chicks were grouped by weight into 6 blocks of 6 cages with 4 birds per cage. Six corn-soybean meal-based mash diets were randomly assigned to cages within each block. The 6 diets were adequate P (7.7 g of P/kg of diet), low P (3.9 g of P/kg of diet), low P diet plus 0.75 or 1.5 g of inorganic P from monosodium phosphate, and low P diet plus the evolved Escherichia coli phytase at 500 or 1,000 units/kg of diet. The chicks were fed the experimental diets from 8 to 22 d of age. The evolved Escherichia coli phytase improved weight gain (P < 0.05), feed intake (P < 0.01), percentage tibia ash (P < 0.01), and retention of P (P < 0.001), Ca (P < 0.01), N (P < 0.05), and a number of amino acids (P < 0.05). The evolved Escherichia coli phytase was, therefore, efficacious in improving broiler growth performance, bone characteristics, and retention of P, Ca, N, and a number of amino acids.