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Background/Objectives: Fortifying cereal staples with zinc is a strategy for increasing zinc intake in young children in developing countries. However, phytic acid (PA) naturally present in cereals strongly decreases zinc absorption. A stable-isotope zinc absorption study was conducted in young children to investigate the ability of the PA-degrading enzyme phytase to improve zinc absorption, when added to a cereal porridge immediately before consumption. Subjects/Methods: Fractional absorption of zinc (FAZ) was estimated in 35 young healthy Burkinabe children using the double-isotopic tracer ratio method with 67 Zn as oral tracer and 70 Zn as intravenous tracer, in a crossover design. The test meals were: (a) a millet-based porridge containing 1.4 mg total zinc (native plus 1 mg added as ZnSO 4 ) with a PA:Zn molar ratio of 7.7; (b) the same porridge with the enzyme phytase (20.5 phytase units (FTU)) added immediately before consumption. The exchangeable zinc pool (EZP) was determined as a potential measure of long-term zinc intake in 20 of the 35 children and compared with FAZ. Results: Mean FAZ increased from 9.5±3.4 to 16.0±5.1% ( P <0.0001), when phytase was added to the meal. The mean EZP was 3.6±0.5 mg/kg. There was no correlation between the EZP and FAZ values for either of the two test meals. Conclusions: Adding phytase immediately prior to consumption of a zinc-fortified cereal-based complementary food can improve zinc absorption in young children.

A 22-week trial was conducted to assess the effects of replacing inorganic phosphorus (P) with two levels of a hybrid bacterial 6-phytase in low-energy diets for laying hens, from 23 to 44 weeks of age. The study focused on hen performance, egg quality and bone health of laying hens. For this purpose, Lohmann Brown Classic hens (n = 432) were randomly allocated to four dietary groups, each comprising nine replicates of 12 birds. The groups included: (1) positive control (PC), a standard diet containing 3.7% calcium, 0.38% non-phytate phosphorus (nPP) and 2730 kcal/kg metabolizable energy (ME), (2) negative control (NC), a diet similar in nutritional specifications to the PC but with reduced nPP (0.12%) and ME (2630 kcal/kg), (3) NC300 and (4) NC600, where NC diets were supplemented with 300 and 600 phytase unit (FTU) per kg feed, respectively. All diets were provided as mash and formulated using corn, soybean meal and sunflower meal as the main ingredients. The NC diet significantly impaired hen performance compared to the PC diet (p < 0.05). Specifically, the NC diet led to deterioration in egg production (p < 0.001), egg weight (p = 0.001), egg mass (p < 0.001), feed intake (p < 0.001), feed conversion ratio (p = 0.002), body weight (p < 0.001), and livability (p = 0.036). Additionally, the NC diet increased the incidence of cracked (p < 0.001) and shell-less eggs (p < 0.001) and lowered eggshell breaking strength (p = 0.005). Bone health was also adversely affected by the NC diet, as indicated by reduced tibia ash content (p < 0.001), stiffness (p = 0.005), and maximum load-bearing capacity (p = 0.040). Moreover, with NC diet, there was a decrease in osteoprotegerin (OPG) expression (p < 0.001) and an increase in receptor activator of nuclear factor kappa-B ligand (RANKL) expression (p < 0.001) in tibia, resulting in a greater RANKL/OPG ratio (p < 0.001). Supplementing the NC diet with bacterial 6-phytase at both levels (300 and 600 FTU/kg) effectively mitigated all adverse effects of P and ME deficiency on the aforementioned parameters, bringing them to levels comparable to those of the PC. Notably, the 600 FTU/kg supplementation provided slightly better results in terms of egg weight and eggshell breaking strength than the 300 FTU/kg level. Overall, this study suggests that supplementing the hybrid bacterial 6-phytase (300–600 FTU/kg) to P-deficient (0.12% nPP) and low energy (−100 kcal/kg) diets can fully replace inorganic P without compromising laying performance, egg quality, or bone health. Further research is recommended to determine the optimal levels of hybrid bacterial 6-phytase in P-deficient diets for laying hens throughout laying cycle of the birds with other nutrient matrices (energy, amino acids, calcium) to optimize layer feed formulations.

Sustainable aquafeed production requires fishmeal replacement, leading to an increasing use of plant-derived ingredients. As a consequence, higher levels of antinutritional substances, such as non-starch polysaccharides and phytate, are present in aquafeeds, with negative effects on fish performance, nutrient digestibility and overall gut health. To alleviate these negative effects, providing exogenous digestive enzymes and/or probiotics can be an effective solution. In this study, we tested the effect of dietary supplementation of enzymes (phytase and xylanase) and probiotics (three strains of Bacillus amyloliquefaciens ) on nutrient digestion kinetics and volatile fatty acid content along the gut, and the distal gut microbiome diversity in Nile tilapia. Chyme volatile fatty content was increased with probiotic supplementation in the proximal gut, while lactate content, measured for the first time in vivo in fish, decreased with enzymes along the gut. Enzyme supplementation enhanced crude protein, Ca and P digestibility in proximal and middle gut. Enzymes and probiotics supplementation enhanced microbial interactions as shown by network analysis, while increased the abundance of lactic acid bacteria and Bacillus species. Such results suggest that supplementation with exogenous enzymes and probiotics increases nutrient availability, while at the same time benefits gut health and contributes to a more stable microbiome environment.

Microbial phytase is widely used to enhance digestibility of phytate-P. By tradition, diets with P content well below requirement are used to quantify phytate-P release by phytase, but P-adequate diets may be more physiologically relevant. The objective of this study was to investigate the effects of phytase on P digestion and metabolism and develop a P release curve for phytase in P-adequate diets (above requirement according to NRC, 2012), and to compare these effects in a P-deficient diet. Three replicates of 24 barrows each (BW = 23.0 ± 1.8 kg) were randomly assigned to 1 of 8 dietary treatments, housed in individual pens for 21 d, then moved to metabolism crates for 5 d urine and fecal collections. A basal corn-soybean meal diet (P-adequate, A) was formulated at 0.36% standardized total tract digestible (STTD) P and total Ca:STTD P of 1.83. Phytase was added to A at 200 (A200), 400 (A400), 600 (A600), and 800 (A800) phytase units (FTU)/kg. A positive control diet (PC) was formulated using monocalcium phosphate (MCP) to increase STTD P by 0.16% to 0.52%, the expected STTD P release of 800 FTU/kg. A P-deficient diet (D) was formulated by reducing MCP to achieve 0.21% STTD P, and 200 FTU phytase/kg was added to D for D200. Pig was the experimental unit, and replicate and dietary treatment were fixed effects. Orthogonal polynomial contrasts were used to test linear and quadratic effects of phytase within A, A200, A400, A600, and A800. Phytase increased percent apparent total tract digestibility (ATTD) and STTD of P (quadratic P < 0.001), and quantity of absorbed P (linear P < 0.001; quadratic P = 0.069). Urinary P increased linearly with phytase (P < 0.001) and retained P also increased (linear P = 0.001, quadratic P = 0.094). Phytate-P release was estimated to be 0.049, 0.080, 0.093, and 0.09% STTD P for 200, 400, 600, and 800 FTU/kg, respectively. It appears that the effect of phytase may be lower in P-adequate diets as compared to P-deficient diets, given that there was a 12% improvement for A200 versus A, and a 28% improvement in STTD P for D200 versus D. In conclusion, phytase improved P digestibility and retention in P-adequate diets, and P digestibility was used to estimate the quantity of P released by phytase. Further research investigating P release by phytase in P-adequate diets, rather than P-deficient diets, may be preferable.

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

The objective of this study was to evaluate the effect of increasing doses of bacterial phytase (RONOZYME HiPhos) on performance and carcass characteristics of growing and finishing pigs. The study included 120 castrated males with initial weight of 23.21 ± 1.91 kg and 68 days of age, distributed in a randomized block design with five treatments and eight replicates with three animals each. The pigs were fed five corn-soybean meal-based diets: positive control (PC), supplemented with inorganic phosphorus and calcium; negative control (NC), with 0.13% reduction in available phosphorus and 0.11% in calcium; and three NC diets supplemented with 1,000, 2,000, and 3,000 phytase units (FYT)/kg in the feed. Compared with the NC diets without phytase, diets with 1,000, 2,000, and 3,000 FYT/kg inclusion increased the daily weight gain by +12% (quadratic, p<0.05) during the growing I period; +2.9, +2.9, and +10.5% (linear, p<0.01), respectively, during the growing II period; and +4.1, +5.1, and +8.2% (linear, p<0.001), respectively, over the entire experimental period. The daily feed intake increased by 0, +2.8, and +4.3% (linear, p<0.05), respectively, considering the entire experimental period; and the final live weight increased by +3.2, +4.2, and +6.1% (linear, p<0.001), respectively. The phytase treatments did not influence feed conversion ratio, carcass weight and yield, backfat thickness, loin depth and carcass lean meat. According to the European Carcass Classification (SEUROP), however, the animals fed the PC diet and the three phytase levels had more carcasses classified as E (between 55-60% lean meat) when compared to carcasses of pigs fed the NC. Supplementing increasing levels of phytase to a corn- and soybean meal-based diet with inorganic P and Ca reduction improved daily weight gain and feed intake of growing pigs, and such effects were maintained until slaughter age.

The value of added feed enzymes (FE) in promoting growth and efficiency of nutrient utilisation is well recognised in single-stomached animal production. However, the effects of FE on the microbiome of the gastrointestinal tract (GIT) are largely unrecognised. A critical role in host nutrition, health, performance and quality of the products produced is played by the intestinal microbiota. FE can make an impact on GIT microbial ecology by reducing undigested substrates and anti-nutritive factors and producing oligosaccharides in situ from dietary NSP with potential prebiotic effects. Investigations with molecular microbiology techniques have demonstrated FE-mediated responses on energy utilisation in broiler chickens that were associated with certain clusters of GIT bacteria. Furthermore, investigations using specific enteric pathogen challenge models have demonstrated the efficacy of FE in modulating gut health. Because FE probably change the substrate characteristics along the GIT, subsequent microbiota responses will vary according to the populations present at the time of administration and their reaction to such changes. Therefore, the microbiota responses to FE administration, rather than being absolute, are a continuum or a population of responses. However, recognition that FE can make an impact on the gut microbiota and thus gut health will probably stimulate development of FE capable of modulating gut microbiota to the benefit of host health under specific production conditions. The present review brings to light opportunities and challenges for the role of major FE (carbohydrases and phytase) on the gut health of poultry and swine species with a specific focus on the impact on GIT microbiota.

An experiment was conducted to test the hypothesis that values for apparent total tract digestibility (ATTD) of Ca in pigs are influenced by endogenous Ca lost from the gastrointestinal tract. The objective was to determine the endogenous loss of Ca, the ATTD of Ca, and the true total tract digestibility (TTTD) of Ca in canola meal without and with microbial phytase. The second objective was to determine the balance of Ca in pigs fed diets based on canola meal without or with microbial phytase. Forty-eight growing barrows (initial BW: 16.72 ± 2.52 kg) were allotted to 8 dietary treatments in a randomized complete block design with 6 pigs per treatment. Diets were based on sucrose, cornstarch, potato protein isolate, corn gluten meal, and canola meal. Diets were formulated to contain 0.08, 0.16, 0.24, or 0.32% Ca from canola meal. All diets were formulated with 0 or 1,500 units/kg of microbial phytase and contained 0.32% digestible P. Feces and urine samples were collected from d 6 to 11. Total endogenous losses of Ca were determined using the regression procedure. Results indicated that ATTD of Ca and Ca retention increased (P < 0.05) if dietary Ca increased and also increased (P < 0.01) when phytase was added to the diets. The estimated total endogenous loss of Ca was 0.160 and 0.189 g/kg DMI for canola meal without and with microbial phytase, respectively, and these values were not different. The TTTD of Ca increased (P < 0.01) if phytase was used but was not affected by the level of dietary Ca. As dietary Ca increased, the amount of Ca absorbed and retained increased (P < 0.01) to a greater extent if phytase was used than when no phytase was included in the diet (interaction, P < 0.05). Fecal P excretion increased (P < 0.01) as dietary Ca increased but was reduced (P < 0.01) by the use of phytase. The ATTD of P decreased (P < 0.01) with increasing dietary Ca to a lesser extent if phytase was used than when no phytase was used (interaction, P < 0.01). In conclusion, endogenous Ca is lost from the gastrointestinal tract of growing pigs, and values for TTTD of Ca are, therefore, different from values for ATTD of Ca. Values for ATTD of Ca are influenced by level of dietary Ca, but that is not the case for values for TTTD of Ca. The ATTD of P decreases as dietary Ca increases, but microbial phytase increases Ca and P digestibility and Ca retention in pigs fed diets based on canola meal whereas it does not influence endogenous losses of Ca.

Background To achieve maximum production in laying hens, calcium (Ca) and phosphorus (P) are two important minerals in the diet. Nutritional solutions such as adding coarser Ca particles in the afternoon or considering the light hours during the night to feed the birds might improve the eggshell quality and reduce Ca mobilization from the bone. Objectives This experiment aimed to study the effect of calcium carbonate particle size (CCps), phytase (Pht) and midnight feeding (MF) on the performance, egg and bone quality and blood parameters in laying hens from 60 to 70 weeks of age. Methods A total of 720 Hy‐line (W‐36) laying hens were arranged in a factorial arrangement of 2 × 2 × 2 based on a completely randomized design with two types of CCps (100% fine and 75% coarse + 25% fine), two levels of Pht (0 and 300 FTU/kg) and two states of feeding (MF and without MF). The experimental period lasted 12 weeks from 60 to 70 weeks of age. Results During the trial, the significant impact of CCps on the feed conversion ratio (FCR) and breaking strength (BS) of the tibia was obtained (p < 0.05). FCR, eggshell percentage and the percentage of tibia ash, Ca and P were affected by Pht supplementation (p < 0.05). MF affected egg weight (EW), eggshell percentage and serum concentration of Ca, P and alkaline phosphatase (ALP) (p < 0.05). The interaction effects of CCps and Pht were significant for Ca level in serum (p < 0.05). Conclusions In general, the use of Pht in the diets improved the FCR and quality of eggshell and tibia, and diets containing Pht and coarser CCps increased blood Ca levels. Despite the improvement of egg quality by MF, serum parameters showed a significant decrease. • 720 Hy‐line (W‐36) laying hens were assigned to eight treatments, with two levels calcium carbonate particle size (fine and coarse), phytase (0 and 300 FTU/kg diet) and midnight feeding (with and without) from 60 to 72 weeks of age. • The use of coarser calcium carbonate particles, phytase and midnight feeding improved the performance, eggshell percentage, tibia characteristics and serum parameters. • Midnight feeding caused a significant decrease in blood calcium and phosphorus levels.

The presence of phytate in broiler diets restricts phosphorus availability, a crucial nutrient for muscle and bone development, leading to reduced performance. To alleviate this issue, exogenous enzymes such as phytase are introduced; however, the wide variety of phytases available on the market and their effectiveness are not yet fully understood. The objective of this study was to evaluate the phosphorus equivalence of commercial phytase in broiler diets, using the standard curve, and its effects on performance, bone mineralization, intestinal histological integrity, liver relative weight, and total alkaline phosphatase in the initial phase (1 to 21 days) of broiler. We used 2,500 male broiler chickens, with an initial weight of 44 g, distributed in a completely randomized design with 10 treatments and 10 replications of 25 birds per experimental unit. The diets were formulated to meet the nutritional requirements of the birds, except for the available phosphorus (Pd) and calcium content. The treatments were divided as follows: T1—Control (CT) with 0.18% Pd; T2—CT + 0.07% aP; T3—CT + 0.14% aP; T4—CT + 0.21% aP; T5—CT + phytase 1; T6—CT + phytase 2; T7—CT + phytase 3; T8—CT + phytase 4; T9—CT + phytase 5; and T10—CT + phytase 6. For enzymatic standardization, 500 FTU/kg (Phytase Units) of each enzyme were used. Animals subjected to the highest levels of P (T2, T3, and T4) and with the addition of commercial phytases (T5, T6, T7, T8, T9, and T10) had better performance and bone mineralization results when compared to T1-CT. All phytases evaluated improved final live weight, weight gain, feed conversion, and ash and phosphorus content in the tibia and intestinal development compared to CT. Supplementing broiler diets with commercial phytases enhances performance, bone mineralization, and jejunal development from 1 to 21 days.The average phosphorus availability from phytic acid in these phytases was 0.154%. The comparison of the six commercial phytases in diets for broiler chickens, using the standard curve and supplementation with 25 g/t of commercial phytase, showed similar results, promoting improvements in performance, bone mineralization, and jejunal development.