A systematic view on the effect of microbial phytase on ileal amino acid digestibility in pigs

Effects of a Novel Consensus Bacterial 6-Phytase Variant on Growth Performance and Bone Ash of Broilers Fed Complex Diets Highly Deficient in Minerals, Digestible Amino Acids and Energy through 42 Days of Age

An experiment was conducted to evaluate the effects of increasing the dose of a novel consensus bacterial 6-phytase variant expressed in Trichoderma reesei (PhyG) in broilers fed complex diets highly deficient in minerals, dig AA, and energy. Diets were a nutrient-adequate control (PC); a nutrient-reduced control (NC) formulated with a reduction in available P (avP) by 0.199%, Ca by 0.21%, crude protein by 0.72-1.03%, dig Lys by 0.064-0.084%, Na by 0.047%, and ME by 87.8 kcal/kg, respectively; and NC supplemented with PhyG at 500, 1000, and 2000 FTU/kg feed. BW was decreased and FCR increased in the NC vs. PC, while the PhyG treatments were similar to the PC. Carcass yield and bone ash were also maintained with PhyG supplementation. Phytase provided economic benefit on a feed cost per kg of weight basis for 1 to 35 d; the cost reductions equated to USD 0.006, 0.016, and 0.02/kg BWG at 500, 1000, and 2000 FTU/kg. In conclusion, this trial demonstrated that supplementation with a novel consensus phytase variant in diets highly deficient in minerals, dig AA, and energy maintained growth performance and provided economic benefit, with production benefits being maximized at inclusion levels of 2000 FTU/kg.

Modern feeding strategies for breeding boars

Feeding of breeding boars in artificial insemination (AI) centers is critical to maintaining and improving breeding quality and performance in agriculture. Modern feeding strategies for AI boars are aiming towards maximizing their lifetime semen dose output. Given the high growth potential of modern swine genetics, AI boars should be controlled in their daily gain to reduce stress factors for the locomotion system, final body weights, and improve their survivability but also the ease of handling boars. The feeding program should be designed in such a way that young boars (up to 7 months of age) are limited to a daily gain of 400-600 g. Mature boars should be fed towards a body condition score of '2'. Aside from energy intake, protein sources should provide 0.62% SID lysine. As far as minerals and vitamins, special attention should be given to Calcium and Phosphorus as they play a crucial role in bone mineralization. A standardized total tract digestible Calcium-Phosphorus ratio between 1.75:1 and 1.82:1 seems to be most favorable. While certain nutritional requirements are needed to enable the production of ejaculates eligible for AI, considerations should be given to the mitigation of risk factors like mycotoxins, herbicides, and pesticides. Most feed additives and supplements lack consistency in their effect across studies evaluated in this review.

Evaluation of exogenous phytase in high-phytate diets for broiler chickens and pigs

There is a gap in the understanding of the relationship between dietary phytate levels and the relative efficacy of phytase to improve amino acid (AA) digestibility in pigs and chickens. Two experiments were conducted to investigate the effect of exogenous phytase on standardized ileal digestibility (SID) of AA and the apparent ileal digestibility (AID) of P in both standard- (SP) and high-phytate (HP) diets for broilers and swine. There were either 40 cages of Cobb 500 male broilers or 10 crossbred barrows (35 kg) fitted with ileal T-cannulas. Both studies were allotted to five dietary treatments (8 replicates). Treatments consisted of four corn-soybean meal-based diets arranged in a 2 × 2 factorial of standard or high phytate and exogenous phytase at 0 or 1 000 phytase units (FYT)/kg; and one N-free diet. Birds were fed a common starter diet from d 0 to 20 and fed experimental diets from d 20 to 25. Birds were euthanized on d 25 via CO2 asphyxiation, and digesta were collected from the terminal ileum. Pigs were fed for a total of four 7-d periods, where digesta were collected on d 6 and 7 of each period. Diet and digesta samples were analyzed for DM, N, Ti, AA, and P to determine AA and P digestibility. The SID of AA was determined by correcting the AID of AA for the basal endogenous losses estimated using the N-free diet. Main effects of the diet type (standard or HP) and phytase (0 or 1 000 FYT/kg), and the interaction of diet type and phytase were evaluated. For both experiments, the HP diets produced lower SID of AA compared to the SP (P < 0.001). For broilers, there was a phytase effect (P < 0.001) for the SID of all AAs evaluated regardless of the diet type. For pigs, phytase improved (P < 0.05) the SID of Met, Lys, Cys, Glu and Ser and tended to improve (P < 0.10) Arg, Leu, Thr, and Tyr. There were no significant interactions for either experiment. For both experiments, AID of P was lower for the HP diets (P < 0.01), and phytase produced greater AID of P for both diet types (P < 0.01). These data indicate that phytase greatly improves the digestibility of P for broilers and pigs and has the ability to significantly increase the digestibility of amino acids for these animals, regardless of the dietary phytate P.

Dietary fibre effects and the interplay with exogenous carbohydrases in poultry nutrition

A comprehensive understanding of the role of dietary fibre in non-ruminant animal production is elusive. Equivocal and conflated definitions of fibre coupled with significant analytical complexity, interact with poorly defined host and microbiome relationships. Dietary fibre is known to influence gut development, feed intake and passage rate, nutrient absorption, microbiome taxonomy and function, gut pH, endogenous nutrient loss, environmental sustainability, animal welfare and more. Whilst significant gaps persist in our understanding of fibre in non-ruminant animal production, there is substantial interest in optimizing the fibre fraction of feed to induce high value phenotypes such as improved welfare, live performance and to reduce the environmental footprint of animal production systems. In order to achieve these aspirational goals, it is important to tackle dietary fibre with the same level of scrutiny as is currently done for other critical nutrient classes such as protein, minerals and vitamins. The chemical, mechanical and nutritional role of fibre must be explored at the level of monomeric sugars, oligosaccharides and polysaccharides of varying molecular weight and decoration, and this must be in parallel to standardisation of analytical tools and definitions for speciation. To further complicate subject, exogenous carbohydrases recognise dietary fibre as a focal substrate and have varying capacity to generate lower molecular weight carbohydrates that interact differentially with the host and the enteric microbiome. This short review article will explore the interactive space between dietary fibre and exogenous carbohydrases and will include their nutritional and health effects with emphasis on functional development of the gut, microbiome modulation and host metabolism.

Digestibility of calcium in calcium-containing ingredients and requirements for digestible calcium by growing pigs

The concentration of Ca in plant feed ingredients is low compared with the requirement for pigs and most Ca in diets for pigs is provided by limestone and Ca phosphate. To determine digestibility values for Ca that are additive in mixed diets, the standardized total tract digestibility (STTD) of Ca needs to be calculated, and the STTD of Ca by growing pigs in most Ca-containing ingredients has been reported. Although Ca is an inexpensive nutrient compared with P and amino acids, excess Ca needs to be avoided because excess dietary Ca results in reduced P digestibility, reduced feed intake, and reduced growth performance of pigs. Recent data indicate that most diets produced for pigs in the United States and Europe contain ~0.20 percentage units more Ca than formulated, which likely is because of the use of limestone as a carrier in feed additives or as a flow agent in other ingredients. An excess of this magnitude without a corresponding excess of P will result in a reduction in daily gain of growing pigs by 50 to 100 g. Greater emphasis, therefore, needs to be placed on determining the concentration of Ca in diets for pigs. Microbial phytase increases the digestibility of both Ca and P and it is, therefore, important that the release of both Ca and P by phytase is considered in diet formulation. However, due to the relationship between Ca and P in postabsorptive metabolism, diets need to be formulated based on a ratio between digestible Ca and digestible P. To maximize average daily gain, this ratio needs to be less than 1.40:1.0 in diets for weanling pigs, and the ratio needs to be reduced as the body weight of pigs increases. In contrast, to maximize bone ash, the digestible Ca to digestible P ratio needs to increase from 1.67:1.0 in 11 to 25 kg pigs to 2.33:1.0 in finishing pigs. Gestating sows have reduced STTD and retention of Ca and P compared with growing pigs and formulation of diets for sows based on digestibility values obtained in growing pigs will result in inaccuracies in the provision of Ca and P. There is, however, a lack of data for the digestibility of Ca and P by gestating and lactating sows, and responses to microbial phytase by sows are not fully understood. There is, therefore, a need for research to generate more data in this area. In the present review, a summary of data for the digestibility of Ca in feed ingredients for pigs and estimates for the requirement for digestible Ca by growing and finishing pigs are provided.

Effects of feeding levels on ileal amino acid digestibility of extruded full fat soybeans in nongestating sows

The objectives of this study were to investigate the effect of feeding levels on amino acid (AA) digestibility of extruded full fat soybeans (EFSB) fed to nongestating sows and to provide a reference for setting feed intake level when evaluating the quality of nutrients in the feed ingested by sows. Twelve nongestating sows (parity 3 to 5) were fitted with a T-cannula at the distal ileum. After recovery, sows were assigned to a replicated 6 × 3 incomplete Latin square design using two diets (nitrogen-free and EFSB) and three levels of feed intake (1.3, 2.0, and 3.4 times the maintenance requirement for metabolizable energy (ME)). The design included six dietary treatments and three periods, and each period contained two replicates for a total of six replicate sows per treatment. All diets contained 0.3% chromic oxide as an indigestible marker. In each period, ileal digesta samples were collected continuously for 12 h on days 6 and 7 after 5 d of acclimation to the experimental diet. Results of the experiment indicated that different feeding levels (1.3, 2.0, and 3.4 times the maintenance requirement for ME) had no effects on apparent ileal digestibility (AID) of AA and standardized ileal digestibility (SID) of AA, but feeding level did affect the endogenous AA loss estimated using the nitrogen-free diet method. Endogenous phenylalanine excretion was greater with 1.3 times than with 3.4 times the maintenance requirement for ME (P = 0.03), and endogenous tyrosine excretion was greater with 1.3 and 2.0 times than with 3.4 times the maintenance requirement for ME (P = 0.01). Increasing feed consumption resulted in greater loss of total endogenous AAs and crude protein (CP). In conclusion, feeding levels of 1.3 to 3.4 times the maintenance requirement for ME did not affect the AID and SID of AA of EFSB fed to nongestating sows.

Chemical composition, energy content and apparent total tract digestibility of extruded full fat soybean from different sources fed to non-gestating, gestating and lactating sows

This experiment was conducted to determine the chemical composition, digestible energy (DE), metabolizable energy (ME) and the apparent total tract (ATTD) of nutrients in six extruded full fat soybean (EFSB) samples from different sources fed to non-gestating, gestating and lactating sows. Forty-two non-gestating sows (Landrace × Yorkshire; parity 3 to 5), 42 gestating sows (Landrace × Yorkshire; parity 3 to 5; day 90 of gestation) and 42 lactating sows (Landrace × Yorkshire; parity 3 to 5; day 6 of lactation) were assigned to seven dietary treatments including a corn-based diet and six diets containing 30.24% EFSB from different sources in a completely randomized design with six replicate sows per dietary treatment. Total fecal and urine collection method was used during non-gestation and gestation, and the index method was used during lactation (0.3% chromic oxide). Differences in the chemical composition of the six EFSB samples from different sources were mainly reflected in ether extract, ash, crude fiber, neutral detergent fiber (NDF), acid detergent fiber, total dietary fiber, insoluble dietary fiber, soluble dietary fiber, and vitamin and micro minerals content, with a coefficient of variation ≥8.37%. The potassium hydroxide solubility of the six EFSB samples varied from 66.60% to 85.55%. There were no differences in ATTD of NDF between different EFSB samples. Additionally, there were no differences in ME values and ME/DE ratios between different physiological stages, but ATTD of NDF were higher for non-gestating and gestating sows than lactating sows (P < 0.01). In conclusion, EFSB can be used as a high-quality energy ingredient with high DE and ME values when fed to sows. DE values of EFSB in non-gestating, gestating, and lactating sows were 20.50, 20.70, and 20.02 MJ/kg, respectively, while ME values of EFSB was 19.76 MJ/kg in both non-gestating and gestating sows.

Ileal and total tract digestibility of energy and nutrients in pig diets supplemented with a novel consensus bacterial 6-phytase variant

An experiment was conducted to test the hypothesis that increasing levels of a novel phytase increases the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in diets fed to young pigs. A negative control (NC) diet based on corn, soybean meal, and canola meal that contained approximately 0.83% phytate (i.e., 0.23% phytate-bound P) was formulated to be deficient in Ca, P, and standardized ileal digestible amino acids (AA). Five additional diets were formulated by adding 250, 500, 1,000, 2,000, or 4,000 phytase units/kg of the novel phytase to the NC diets. Eighteen ileal-cannulated pigs (17.81 ± 1.71 kg) were allotted to a 6 × 3 incomplete Latin square design with six diets and three 11-day periods. There were three pigs per diet in each period; therefore, there were nine replicate pigs per diet. The initial 5 d of each period was considered an adaptation period to the diet. For each period, fecal samples were collected via anal stimulation on days 6, 7, 8, and 9, whereas ileal digesta were collected on days 10 and 11 using standard procedures. Results indicated that the AID of crude protein, indispensable AA, and dispensable AA was increased (quadratic, P < 0.05) as the concentration of microbial phytase increased in the diets. Dietary inclusion of the novel phytase at 1,000 or 2,000 FTU/kg increased the AID of total AA from 73.7% to 79.8%. Increasing levels of microbial phytase increased (quadratic, P < 0.05) the AID of dry matter and minerals (i.e., Ca, P, K, Mg, Cu) in the diets. Likewise, a linear increase (P < 0.05) in the AID of ash and Na was observed as the inclusion level of phytase increased in the diets. Increasing levels of microbial phytase increased (linear, P < 0.01) the AID of gross energy (GE) and starch in the diets. A quadratic (P < 0.05) increase in the ATTD of ash, Ca, P, K, and Cu in experimental diets was observed as the concentration of microbial phytase increased in the diets. The ATTD of Mg and GE also increased (linear; P < 0.05) as concentration of dietary phytase increased. In conclusion, the novel microbial phytase used in this experiment was effective in increasing the AID of dry matter, GE, starch, minerals, and AA, as well as the ATTD of gross energy and minerals in diets formulated to be deficient in Ca, P, and AA.

Apparent digestibility of energy and nutrients and efficiency of microbial phytase is influenced by body weight of pigs

An experiment was conducted to test the hypothesis that regardless of pig body weight (BW), increasing dietary phytase results in increased phytate degradation and improved digestibility of minerals, amino acids (AA), and gross energy (GE). Eighteen pigs were equipped with a T-cannula in the distal ileum and allotted to a triplicated 6 × 3 Youden square design with six diets and three collection periods of 7 d, for a total of nine replicate pigs per diet. This design was repeated four times to simulate four production phases, and there was a 7-d resting period before each collection phase started (BW at start of collections: 29.3, 53.6, 85.1, and 114.4 kg for phases 1, 2, 3, and 4, respectively). Six corn-soybean meal diets were formulated by including 0, 250, 500, 1,000, 2,000, or 4,000 phytase units/kg feed (FTU). The six diets were used throughout the experiment. Samples of feces and ileal digesta were collected in each period. Results indicated that regardless of pig BW, increasing inclusion of phytase increased (quadratic; P < 0.05) apparent ileal digestibility (AID) of crude protein (CP) and most AA, increased apparent total tract digestibility (ATTD) of Ca, P, K, Mg (linear and quadratic; P < 0.05), and Na (linear; P < 0.05), but decreased (linear and quadratic; P < 0.05) AID and ATTD of GE. In all phases, ileal concentrations of inositol phosphate (IP) 6, IP5, IP4, and IP3 decreased (linear and quadratic; P < 0.05), whereas ileal inositol increased (linear and quadratic; P < 0.05) with increasing dietary phytase. However, as pig BW increased, AID of GE, CP, and AA increased (linear, P < 0.05), and the AID of a few AA (Met, Phe, Thr, Trp, Ala, Asp, Gly, and Ser) also increased quadratically (P < 0.05). The ATTD of GE, K, and Mg increased (linear and quadratic; P < 0.05), but ATTD of Ca and Na (linear; P < 0.05) and of P (linear and quadratic; P < 0.05) decreased as pig BW increased. Ileal IP6 and IP3 (linear and quadratic; P < 0.05) and ileal IP5 and IP4 (linear; P < 0.05) increased, whereas ileal inositol decreased (linear; P < 0.05) as pig BW increased. In conclusion, regardless of pig BW, increasing dietary phytase increased phytate degradation and inositol release in the small intestine, and consequently increased mineral and AA digestibility. Older pigs have reduced Ca, P, and Na digestibility, but increased K, Mg, AA, and GE digestibility compared with younger pigs. The efficiency of dietary phytase to degrade phytate appears to decrease as pigs get older.

Increasing Doses of Bacterial Phytase (Citrobacter braakii) Improves Performance and Carcass Characteristics of Pigs in Growing and Finishing Phases

Simple Summary

Phytases of bacterial origin are the exogenous enzymes most widely used in the diets of monogastric animals, acting on the hydrolysis of phytate (myo-inositol 1,2,3,4,5,6-hexakis [dihydrogen] phosphate) to release the phosphate from this complex. However, the efficiency of phytase varies according to the aspects inherent to its own structure and origin, the age and physiological state of the animal, and the dietary composition. Overall, we found that supplementation with phytase between 1500 and 3000 units of phytase (FYT)/kg of feed in diets based on corn and soybean meal with a reduction in inorganic phosphorus (0.13%) and calcium (0.11%) improves the daily weight gain (DWG) and live weight (LW) of animals in the growing phase, which affects performance on finishing phases and slaughter body weight. This input could result in a reduction in the use of phosphorus sources, improving environmental issues with an increase in the main zootechnical parameters.

Abstract

The effects of increasing doses of bacterial phytase (Citrobacter braakii) on performance and carcass characteristics of growing-finishing pigs was evaluated. A total of 120 barrows weighing 25.16 ± 2.80 kg and 68 days old were submitted to five treatments: positive control diet (PC) containing inorganic phosphorus (P) and limestone (Ca); negative control (NC) with reductions in P (by 0.13%) and Ca (by 0.11%); and three NC diets supplemented with 1500 (NC15), 3000 (NC30) and 4500 (NC45) units of phytase (FYT)/kg. The daily weight gain (DWG) in growth phase I (68–91 days) was higher in the PC, NC15 and NC30, compared to the NC (1.06, 1.06, 1.06 vs. 0.95, respectively). The DWG in finishing phase II (141–156 days) was higher in the NC15 (1.20 kg) and NC30 (1.14 kg) than in the NC45 (0.94 kg). The final weights (LW156) in the NC15 (122.95 kg LW) were higher than NC (116.47 kg LW) and NC45 (114.43 kg LW). Over the entire period, a quadratic effect (2012 FYT) was observed for the DWG. The increasing levels of phytase in corn and soybean meal-based diets improved the DWG and carcass traits; however, the addition of more than 3000 FYT/kg of feed should be carefully studied to determine enzyme viability.

Calcium chloride is a better calcium source rather than calcium carbonate for weanling pigs

Two experiments were conducted to evaluate the effects of calcium (Ca) levels in weanling pigs (Landrace × Yorkshire × Duroc). In experiment 1, one hundred and eighty weanling pigs were randomly allotted to one of the three treatments. The treatments were low (Ca 0.60% in phase 1 and 0.50% in phase 2), standard (Ca 0.72% in phase 1 and 0.66% in phase 2), and high (Ca 0.84% in phase 1 and 0.72% in phase 2). In experiment 2, hundred and forty weanling pigs were randomly assigned to one of four treatments differing in Ca levels (high and low) and sources (CaCl₂ and CaCO₃) in a 2 × 2 factorial arrangement. There were 10 pigs per replicate in both experiments, with 6 replicates in each treatment, and they were conducted in two phases (phase 1, days 0–14; phase 2, days 15–28). In experiment 1, body weight (BW), average daily gain (ADG), and growth to feed ratio (G/F) increased as the Ca level decreased (p < 0.05). P digestibility was higher in the low-Ca diet group than in the high-Ca diet group (p <0.05). In experiment 2, the final BW, ADG, and G/F increased in the CaCl₂ diet group compared with the case in the CaCO₃ diet group (p < 0.05). The digestibility of crude protein (CP), Ca, and P was higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Cl⁻ levels were higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). The bicarbonate (HCO₃⁻), base excess (BE), and electrolyte balance (EB) levels were lower in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Hematocrit increased as the Ca level decreased (p < 0.05). The HCO₃⁻ interacted with the Ca sources and thus, affected the Ca levels (p < 0.05). Bone ash, Ca, and P were downregulated in the low-Ca diet group compared with the case in the high-Ca diet group. Overall, the low dietary Ca supplementation led to greater growth performance. Furthermore, CaCl₂ appeared to be a better Ca source than CaCO₃ because of the greater digestibility of CP, Ca, and P, and improved EB.

Amino acids and energy digestibility in extruded or roasted full fat soybean fed to broiler chickens without or with multienzyme supplement containing protease, phytase, and fiber degrading enzymes

Effects of processing and multienzyme supplement (MES) on standardized ileal digestibility (SID) of amino acids, apparent retention (AR) of components and metabolizable energy (AME) content in full fat soybean seeds (FFSB) were investigated in broiler chickens. The FFSB were either extruded (EFFSB) or roasted (RFFSB). A nitrogen free diet (NFD) was formulated for SID of AA calculation. The FFSB diets contained 20% crude protein with the ratio of corn starch: sucrose: soy oil (sole sources of energy in NFD) kept constant for calculation of AME. The FFSB diets were fed without or with MES containing phytase, protease, and fiber degrading enzymes. All diets had TiO2 indigestible marker. A total of 400-dayu-old Ross 708 male chicks were fed a commercial diet to d 13. On d 14, birds were weighed individually and allocated to cages (10 birds/cage, n = 8). Birds had free access to feed and water. Excreta samples were collected on d 18 to 20, and all birds were necropsied on d 21 for terminal ileal digesta samples. There was no (P > 0.05) interaction between processing and MES on SID of AA. Birds fed EFFSB had higher (P ≤ 0.048) SID of Arg, Ile, Lys, and Met than birds fed RFFSB. Birds fed MES had higher (85.5 vs. 80.8%; P = 0.050) SID of Lys than birds fed non-MES diet. There was interaction (P ≤ 0.036) between processing and MES on AR of Ca and P; MES improved retention but largely in EFFSB. There was an interaction (P = 0.016) between processing and MES on energy utilization such that MES improved AR of GE, AME, and AMEn in RFFSB only. In general, birds fed EFFSB exhibited higher (P < 0.01) energy utilization than birds fed RFFSB. In conclusion, lower Lys and energy utilization in RFFSB relative to EFFSB reflected the impact of the processing regimen. Supplemental enzyme improvement on Lys and minerals digestibility in FFSB and energy utilization in RFFSB suggested value in heat processed feedstuffs.

Prediction of calcium and phosphorus requirements for pigs in different bodyweight ranges using a meta-analysis

Several studies have focused on Ca and P requirements for pigs. These requirements are estimated from their retention and bone formation. However, modern pig breeds have different responses to dietary Ca and P than traditional breeds, and their requirements are expected to change on an annual basis. Besides individual Ca and P needs, the Ca to P ratio (Ca/P) is an important factor in determining requirements. This study aimed to implement a linear and quadratic regression analysis to estimate Ca and P requirements based on average daily gain (ADG), apparent total tract digestibility (ATTD) of Ca (ATTD-Ca), ATTD of P (ATTD-P), and crude protein (CP) digestibility. Results show that Ca/P had linear and quadratic effects on ADG in the phytase-supplemented (PS) group in both the 6–11 kg and 11–25 kg categories. In the latter category, the CP digestibility was linearly increased in response to increasing Ca/P in the without-phytase (WP) group. In the 25–50 kg category, there was a linear response of ADG and linear and quadratic responses of CP digestibility to Ca/P in the PS group, while a linear and quadratic increase in CP digestibility and a quadratic effect on ATTD-Ca were observed in the WP group. In the 50–75 kg category, Ca/P had significant quadratic effects on ADG in the PS and WP groups, along with significant linear and quadratic effects on ATTD-Ca. In addition, Ca/P had significant quadratic effects on ATTD-P and led to a significant linear and quadratic increase in the CP digestibility in the WP group. In the 75–100 kg category, analysis showed a significant decrease in ATTD-Ca and ATTD-P in the PS and WP groups; in the latter, ATTD-P and ATTD-Ca were linearly decreased by increasing Ca/P. In conclusion, our equations predicted a higher Ca/P in the 6–25 kg bodyweight categories and a lower Ca/P in the 50-100 kg category than that recommended in the literature.

Effects of supplementation of high-dosing Trichoderma reesei phytase in the corn-wheat-soybean meal-based diets on growth performance, nutrient digestibility, carcass traits, faecal gas emission, and meat quality in growing-finishing pigs

We conduct this study to investigate the effects of corn-wheat-soybean meal (SBM)-based diet supplemented with high-dosing Trichoderma reesei phytase on the growth performance, nutrient digestibility, carcass traits, faecal gas emission and meat quality in growing-finishing pigs (29.71-110.58 kg live weight; 70-day-old to 166-day-old). A total of 56 crossbred pigs [(Landrace × Yorkshire) × Duroc] were used in 96-day experiment with a completely randomized block design. The growing period was from day 0 to 42, and the finishing period was from day 43 to 96. Pigs were randomly allocated to one of two treatments with seven replicate pens and four pigs (two barrows and two gilts) per pen and fed corn-wheat-SBM-based nutrient adequate basal diet or the basal diet supplemented with 1500 FTU/kg diet Trichoderma reesei phytase. One phytase unit (FTU) was defined as the amount of enzyme that catalyses the release of one micromole phosphate from phytate per minute at 37°C and pH 5.5. Dietary supplement with Trichoderma reesei phytase had increased body weight on day 96 and average daily gain in days 0-96. Moreover, high apparent total tract digestibility (ATTD) of phosphorus (P) was observed in pigs fed with Trichoderma reesei phytase. However, the carcass traits, faecal gas emission and meat quality of pigs were unaffected by Trichoderma reesei phytase supplementation. In conclusion, supplementation of high-dosing Trichoderma reesei phytase (1500 FTU/kg diet) in the corn-wheat-SBM-based nutrient adequate basal diet increased body weight and the ATTD of P, while no adverse effects were observed on the production characteristics.

Reevaluation of Phytase Action Mechanism in Animal Nutrition

The release of phosphorus from phytates occurs via sequential cleavage of phosphate groups. It was believed that, regardless of the properties of phytases, the rate of phytate dephosphorylation is limited by the first cleavage of any phosphate group. The position of the first cleaved-off phosphate group depending on the specificity of phytase. The inhibition of dephosphorylation initiation is not associated with the action mechanism of the enzyme and can be rather due to the insufficient phytase activity or low availability of phytates. The analysis of the transformations in the inositol hexakisphosphate (IP₆)→inositol (I) reaction chain shows that IP₆ dephosphorylation as a whole limits the phosphate group removal from I(1,2,5,6)P₄ (third reaction from the beginning of hydrolysis of phosphate bonds in PA). The lower availability of nutrients in the presence of phytates is not due to action of phytates, but is caused by PA anions (IP_6-3), which bind positively charged metal ions, amino acids, and proteins. The availability of nutrients increases as a result of the decrease in their binding caused by the decrease in the concentration of IP_(6-3) anions under the action of phytases. Phytases added to feeds play a lesser role in the digestion of phytates compared to natural enzymes and complement their action. The concept of extra-phosphoric effect has no scientific justification, since phytases exhibit only the phosphohydrolase activity and are not able to catalyze other reactions.

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.

Toward standardized amino acid matrices for exogenous phytase and protease in corn-soybean meal-based diets for broilers

A total of 468 male Ross 308 broilers were used in a digestibility study to determine the additivity of apparent or standardized amino acid (AA) digestibility values for corn, soybean meal (SBM), or a mixture of corn and SBM that were supplemented, or not, with either phytase, protease, or a combination of phytase and protease. These treatments generated a total of 12 experimental diets that were arranged in a 3 × 4 design. A nitrogen-free diet was also fed to estimate endogenous AA loss. Apparent and standardized AA digestibility values were assessed on day 28 posthatch. The apparent digestibility of AA in the complete diet was higher (P < 0.05) than expected based on the digestibility of the corn and SBM individually. However, this overestimation was corrected by the adjustment to standardized values. Importantly, addition of protease or the combination of protease and phytase increased (P < 0.05) the digestibility of AA in corn and SBM. Furthermore, these effects were arithmetically coherent with respect to the measured effects of the enzymes in the mixture of corn and SBM, even improving the additivity of AA digestibility values when assessed on an apparent basis. This study demonstrates that the effect of exogenous protease and phytase on AA digestibility in complete diets is predictable based on measurements made in individual ingredients. In addition to improving digestibility values per se, exogenous protease and phytase may enhance precision in least cost formulation systems.

Digestibility of amino acids, energy, and minerals in roasted full-fat soybean and expelled-extruded soybean meal fed to growing pigs without or with multienzyme supplement containing fiber-degrading enzymes, protease, and phytase

Indigestible fiber-protein-phytate complexes reduce the feeding value of soy products. We investigated the effects of multienzyme supplement (MES, Victus) on standardized ileal digestibility (SID) of amino acids (AA) and apparent total tract digestibility (ATTD) of energy and minerals in roasted full-fat soybean (FFSB) seeds and expelled-extruded soybean meal (SBM) fed to growing pigs. The crude protein (CP) was 33.4% and 42.8% dry matter (DM) in FFSB seeds and SBM, respectively and corresponding values for crude fat were 17.4% and 11.8% DM. Semi-purified diets with 50% of either FFSB seeds or SBM as the sole source of AA were prepared without or with MES supplying phytase, protease, xylanase, and β-glucanase at 2,200, 8,300, 400, and 100 U/kg of feed, respectively. Diets had TiO2 as an indigestible marker and the ratio of cornstarch to sucrose and corn oil was identical to calculate DE by the difference method. Eight ileal-cannulated barrows (22.1 ± 0.61 kg) were fed diets in a replicated 4 × 4 Latin square design to give eight replicates per diet. The period lasted for 9 d: 5 d for acclimation, 2 d for fecal, and 2 d for ileal digesta samples. There was no (P > 0.05) interaction between soy type and MES or MES effect on SID of AA; SBM had higher (P < 0.05) SID of CP, His, Leu, and Lys. There was no (P > 0.05) interaction between soy type and MES on energy digestibility. The FFSB seeds had higher ATTD of gross energy (GE, 80.2% vs. 76.6%; P < 0.01) than SBM. Pigs fed MES had higher (P < 0.05) ATTD of DM (91.3% vs. 87.7 %), GE (87.5% vs. 82.4%), CP (86.4% vs. 82.9%), crude fat (70.6% vs. 54.9%), Ca (63.2% vs. 60.2%), and P (67.5% vs. 63.2%). In conclusions, differences on AA and energy digestibility in soy products could be linked to processing and compositional differences. Although MES had no effect on SID of AA, the effects on the utilization of minerals and energy demonstrated the value of fiber-degrading enzymes, protease, and phytase in improving the nutritive value of soy products independent of processing.

Assessing current phytase release values for calcium, phosphorus, amino acids, and energy in diets for growing-finishing pigs. Transl Anim Sci 2020;4:txaa034. [PMID: 32705032 DOI: 10.1093/tas/txaa034]

Two experiments were conducted to determine the effects of feeding 1,500 phytase units (FYT/kg; Ronozyme HiPhos 2,500; DSM Nutritional Products, Parsippany, NJ) when credited with its corresponding nutrient release values to growing-finishing pigs. The assumed phytase release values were 0.146% standardized total tract digestible (STTD) P, 0.102% STTD Ca, 8.6 kcal/kg of net energy (NE), and 0.0217%, 0.0003%, 0.0086%, 0.0224%, 0.0056%, 0.0122%, and 0.0163% standardized ileal digestible Lys, Met, Met+Cys, Thr, Trp, Ile, and Val, respectively. In Exp. 1, 1,215 pigs (PIC 359 × Camborough, initially 28.0 ± 0.46 kg) were used. Pens were assigned to one of three dietary treatments with 27 pigs per pen and 15 pens per treatment. Experimental diets consisted of a control with no added phytase or diets with 1,500 FYT fed either in the grower period (days 0-57) then switched to the control diet until market or fed throughout the entire study (day 0 to market). Diets containing added phytase were adjusted based on the supplier-provided expected nutrient release values. During the grower period, pigs fed the control diet with no added phytase had increased (P < 0.05) average daily gain (ADG) and gain-to-feed ratio (G:F) compared with pigs fed added phytase. Overall, pigs fed either the control or phytase only in the grower period had increased (P < 0.05) ADG and G:F compared with pigs fed phytase until market. In Exp. 2, 2,268 pigs (PIC 337 × 1050, initially 28.5 ± 1.96 kg) were used. There were six dietary treatments with 27 pigs per pen and 14 pens per treatment. Experimental diets consisted of a control with no added phytase or five diets with 1,500 FYT assuming nutrient release values for Ca and P; Ca, P, and Amino Acid (AA); Ca, P, AA, and half of the suggested NE; Ca, P, AA, and full NE; or no nutrient release. Overall, there was no evidence for difference in ADG or average daily feed intake among treatments; however, pigs fed the diet containing 1,500 FYT assuming that no nutrient release had improved (P < 0.05) G:F compared to pigs fed diets containing 1,500 FYT assuming either Ca and P or Ca, P, AA, and full NE release, with others intermediate. In summary, pigs fed phytase-added diets accounting for full nutrient release values in both experiments had the poorest performance. This suggests that using all of the nutrient release values attributed to this source of phytase was too aggressive and resulted in lower nutrient concentrations than needed to optimize performance.

Contribution of individual broilers to variation in amino acid digestibility in soybean meal and the efficacy of an exogenous monocomponent protease

A total of 72 male Ross 308 broilers were reared to day 34 on a standard wheat and soy-based diet and then offered one of the four semisynthetic experimental diets, comprising two different soybean meal sources either without or with exogenous protease (treatments therefore offered in a 2*2 factorial arrangement). Each experimental diet was fed to 18 individually housed birds from 34 to 37 D after which ileal digesta were collected and digestibility coefficients were calculated. The two soybean meal sources were found to be nutritionally divergent (P < 0.01), with one having the apparent ileal amino acid digestibility coefficient of 0.80 and the other 0.71. Exogenous protease increased (P < 0.01) apparent ileal amino acid digestibility coefficients from 0.74 to 0.77. There were no interactions between soybean meal origin and protease effect. On an individual bird level, there were substantial differences in the capacity to digest amino acids with the mean total amino acid digestibility coefficients from 0.54 to 0.80 for one of the soybean meal samples. Exogenous protease addition reduced the coefficient of variation for total amino acids from 11.4 to 9.1% in one soybean meal and from 7.7 to 6.3% in the other. It can be concluded that soybean meal digestibility varies and that some of this variance is associated with heterogeneity in the digestive capacity of broilers.

Lactic Acid Treatment of Cereals and Dietary Phytase Modified Fecal Microbiome Composition Without Affecting Expression of Virulence Factor Genes in Growing Pigs

Besides the major nutrients, phosphorus (P) is an essential mineral for both the host animal and the porcine gut microbiota. Different strategies including phytase supplementation and more recently lactic acid (LA) are used to enhance the P availability from cereals in pig diets; however, their impact on the gut microbiota has been rarely related to fecal shedding of opportunistic pathogens. The present study investigated the effect of phytase supplementation and the treatment of dietary cereals with 2.5% LA on the fecal microbiome composition of metabolic active bacteria and expression of virulence factor genes of enterotoxigenic Escherichia coli and Clostridium perfringens in growing pigs. Phytase supplementation reduced the fecal abundance of the most abundant Lactobacillaceae family, whereas the LA-treatment of cereals had a stronger impact on the bacterial community, reducing amylolytic, pullulanolytic and hemicellulolytic Lactobacillaceae, Lachnospiraceae and Ruminococcaceae as well as the fecal bacterial species richness (Chao1) and diversity (Shannon index). Mainly the family Clostridiaceae benefited from the decline in the aforementioned families, being enriched by both dietary treatments. Multigroup data integration using sparse partial least squares-discriminant analysis showed that among the most discriminative operational taxonomic units (OTU) especially two unclassified Clostridiaceae-OTUs, one Prevotella copri-like OTU and one OTU within the vadinCA11 group were associated with calcium and P levels but were negatively linked with complex carbohydrates in feces. Heat-stable toxin A (Sta) of enterotoxigenic E. coli and Stx2e of Shiga-toxin producing E. coli were expressed in feces but were similar among feeding groups. Without modifying the total bacterial gene copies and virulence factor expression of E. coli, both dietary phytase supplementation and LA-treatment of cereals drastically altered the bacterial community composition in pig feces. Results thereby allowed for the characterization of bacterial nutrient dependencies, indicating a link between fecal P availability, complex carbohydrate composition and alterations in the predominant genera.

Insoluble dietary fiber does not affect the ability of phytase to release phosphorus from phytate in the diet of nursery pigs1

Phytase is added to swine diets to improve the utilization of phytate-bound P in swine diets. This provides financial and environmental benefits to the pig industry. However, it is unclear if phytase works equally well in all dietary circumstances. The objective of this experiment was to determine if insoluble fiber affects the efficacy of the phytase enzyme in nursery pigs when fed diets limiting in P content. A total of 480 pigs (initial BW 5.48 ± 0.14 kg) were blocked by BW and randomly assigned (10 pigs per pen) to treatment within the block. A common nutrient-adequate diet was fed from days -14 to -5, and two basal P deficient diets (either a corn-soy diet containing 0.16% standardized total tract digestible [STTD] P [low insoluble fiber [LF]], or a corn-soybean meal plus 20% corn bran containing 0.14% STTD P [high insoluble fiber [HF]]) were fed from days -5 to 0 to acclimate pigs to a P deficient diet. From days 0 to 21, pigs received eight dietary treatments (six pens per treatment: n = 6). Experimental diets consisted of LF supplemented with one of four levels of added phytase (0, 109, 218, and 327 phytase units [FTU]/kg; Quantum Blue 5 G, AB Vista, Wiltshire, United Kingdom) expected to provide 0.16, 0.21, 0.26, and 0.31% STTD P, respectively, or HF supplemented with one of the same four levels of added phytase expected to provide 0.14, 0.19, 0.24, and 0.29% STTD P. Titanium dioxide was added to the diet at 0.4% as an indigestible marker. On day 21, one pig representing the average BW for each pen was euthanized, and fibulae were collected and analyzed for bone ash. Fecal samples were collected from each pen on days 19-20. Data were analyzed using PROC MIXED of SAS. There were no interactions between insoluble fiber and phytase for any of the variables evaluated. For days 0-21, adding phytase increased ADG (P < 0.001) with the response being linear (P < 0.001), whereas insoluble fiber decreased ADG (P = 0.033). There were no effects of phytase or insoluble fiber on ADFI (P = 0.381 and P = 0.632, respectively). Phytase improved G:F ratio (P < 0.001) with the response being linear (P < 0.001). Insoluble fiber tended to decrease G:F ratio (P = 0.097). Phytase increased bone ash (P = 0.005) with the response being linear (P = 0.001), but there was no effect of insoluble fiber (P = 0.949). Phytase did not affect the apparent total tract digestibility of DM, NDF, or ADF (P > 0.050), whereas insoluble fiber decreased the ATTD of DM (P < 0.001), NDF (P < 0.001), and ADF (P < 0.001). In conclusion, the addition of insoluble fiber did not affect the ability of phytase to improve growth performance and bone mineralization in nursery pigs fed a P deficient diet.

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.

A critical review of methods used to determine phosphorus and digestible amino acid matrices when using phytase in poultry and pig diets

Phytase is applied in animal feed based on its standard activity measured at pH 5.5, however the relative activity at pH 3 (e.g. stomach pH, the main site for the breakdown of phytate) varies among the commercial phytases, ranging from 56% (an E coli phytase) to 235% (Buttiauxella phytase). These diverse sources of phytases have varying capability for degrading phytate and, correspondingly, different P, digestible amino acid and metabolisable energy matrix values. In addition, the matrix values recommended by different phytase suppliers are not comparable, as different methodologies have been used to determine them. Phosphorus (P) and other matrix values can be determined by direct measurement of digestible P (dP) improvements by the addition of phytase above a negative control in large numbers of in vivo studies using increasing phytase doses. Alternatively, matrix values can be assessed by indirect measurement, using inorganic P (usually mono- or dicalcium sources) as a reference, typically based on tibia or metacarpal ash as a response parameter to estimate available P equivalence, either at a single or different phytase doses. When using the indirect measurement, the available P equivalence with increasing phytase doses may be calculated based on a log linear model. Although both methods are acceptable methodologies, direct measurement may under-estimate and indirect measurement may over-estimate matrix values, and a large number of in vivo studies give the best estimates of matrix values. Phytase efficacy can be influenced by phytase source, dose level, dietary composition (Ca level and Ca: P ratio). Phytase end users are encouraged to be aware of the methods used by suppliers to determine matrix values, before applying them in their feed formulations.

Time-series responses of swine plasma metabolites to ingestion of diets containing myo-inositol or phytase

The effect of the ingestion of diets containing either myo-inositol or exogenous phytase on plasma metabolites was examined using 29 kg barrows. The diets were: control (maize, soya, rapeseed, rice bran), control plus 2 g/kg myo-inositol, control plus 1000 phytase units (FYT)/kg or 3000 FYT/kg exogenous phytase. Pigs were housed in a PigTurn device and blood was collected, from jugular catheters, via an automated system at -30, (30 min before feeding), 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360 min post-feeding. The addition of 2 g/kg myo-inositol to the basal diet resulted in an increase in plasma myo-inositol concentration that was evident 45-60 min after diet introduction and persisted to 360 min post-feeding. Similarly, supplementation of the basal diet with either 1000 or 3000 FYT/kg exogenous phytase resulted in an increase in plasma myo-inositol concentration that was still rising 360 min post-feeding. Plasma P concentration was increased over time by the addition of 1000 and 3000 FYT/kg phytase, but not by the addition of myo-inositol. Other plasma metabolites examined were not affected by dietary treatment. It can be concluded that oral delivery of myo-inositol results in rapid increase in plasma myo-inositol concentrations that peak approximately 45-60 min after feeding. Use of supplemental phytase achieves similar increases in myo-inositol concentration in plasma but the appearance is more gradual. Furthermore, supplementation of pig diets with exogenous phytase results in rapid appearance of P in plasma that may be sustained over time relative to diets with no added phytase.