Two feeding trials were conducted to evaluate the effects of dietary phytic acid contents and removal of phytate from plant protein sources on growth and utilization of phosphorus, zinc and iron in juvenile cobia. In experimental I, test diets were formulated by adding phytic acid, 0, 5, 10, 15 and 20 g/kg diet to the basal diet that used fish meal and wheat gluten as the protein source. Juvenile cobia with an initial weight of 20g were fed the test diets for 8 weeks. No significant difference among fish groups was found in percent weight gain, feed conversion ratio, protein efficiency, net protein utilization and body composition. Dietary phytic acid level significantly affected zinc concentrations in body, vertebra, serum and feces. Body zinc concentration in fish fed diet containing 2% phytic acid was 10.2% lower than the control group. Vertebra and serum zinc concentrations decreased with increasing dietary phytic acid levels, vertebra zinc concentration in fish fed diet containing 2% phytic acid was 22.3% lower than the control group. The dietary phytic acid concentration was positively related to the fecal zinc concentration. In experimental II, nine isonitrogenous, isolipid and isocaloric diets were formulated including control diet that contained 421g/kg fish meal, and four test diets with fish meal protein in control diet being replaced by 40 or 50% with soybean meal or by 30% or 40% with canola meal respectively. Another four test diets used dephytinized soybean or canola meal after phytase treatments removed 90.9~94.6% of phytate. Juvenile cobia with an initial weight of 94g were fed the test diets for 8 weeks. Growth, feed conversion ratio, protein efficiency and net protein utilization of fish fed diets containing plant proteins were poorer than control group. Better weight gain, feed conversion ratio and net protein utilization were observed in those groups fed diets contained soybean meal rather than canola meal. Ash, phosphorus, zinc and iron contents of whole body and vertebra in cobia fed phytase-pretreated plant protein were not significantly different from groups of fish fed raw plant protein. In conclusion, dietary phytic acid reduced the zinc bioavailability. Performance of cobia as well as diet quality indicated that soybean meal as the better alternative protein source for fish meal than canola meal. Dephytinization had no positive effect on utilization of phosphorus, zinc and iron in juvenile cobia.

In environments characterized by low pH and/or high nitrate, the biomineralization of U(VI)-phosphate minerals represents a uniquely suited bioremediation method involving microbially-mediated hydrolysis of organophosphates coupled to a chemical precipitation of sparingly soluble U(VI)-phosphate minerals. In this study, the ability of natural microbial phytases to hydrolyze phytate, a naturally-occurring and abundant organophosphate, and precipitate uranium-phosphate minerals was investigated through a combination of sediment microcosms, soil slurries, and pure culture studies. In this study, biomineralization of U(VI)-phosphate minerals promoted by addition of glycerol-2-phosphate was shown to outcompete bioreduction in anaerobically-maintained sediment microcosms containing contaminated soils. Addition of phytate to aerobic soils slurries containing ORFRC soils also resulted in significant production of inorganic phosphate, and two microorganisms that efficiently hydrolyze phytate were isolated from these experiments. Overall, the results of this study demonstrate phytate hydrolysis by subsurface microorganisms coupled to precipitation of U(VI)-phosphate minerals for the first time, suggesting that phytate may represent an ideal organophosphate to promote this process.

Hohenheim, Univ., Diss., 1997.

Zugl.: Berlin, Freie Univ., Diss., 2010

Currently, feed enzyme supplementation into commercial broiler diets is a routine practice due to hydrolysis of antinutrients, such as non-starch polysaccharides (NSP) and phytate (IP6); ultimately leading to optimized broiler production. As a result, the market has grown rapidly, and a multitude of feed enzymesare commercially available. Complete removal of antinutrients has not been achieved and research has primarily focused on the use of singular enzyme inclusion. Due to biochemical differences among enzyme characteristics, there may be potential for synergistic action to remove antinutrients and further maximize broiler performance. Therefore, the overall objective of this dissertation was to investigate enzyme strategies to determine optimal inclusion for broilers. Chapter 2 investigated the interactive effects of phytase dose (PD; 250 to 1500 FTU/kg) and carbohydrase enzyme (CE) of xylanase (XAN), β-mannanase (MAN), or their combination (XM). These data demonstrated an interaction between CE and PD for d 0-14 FCR, but this significance was lost during the remainder of the study. Overall benefits for performance and processing were demonstrated with feeding a PD of 1500 FTU/kg and XAN. Chapter 3 took a preliminary approach (0-14 d) to investigate the potential synergy among 3 phytase enzymes of varying biochemical properties when fed alone or in combination with low PD (120 or 240 FTU/kg). These data demonstrated potential synergy with the supplementation of 2 phytases combined at a higher PD (240 FTU/kg), as identified from ileal IP (inositol phosphate) lower ester concentration and tibia ash. Chapter 4 built upon the previous chapter, choosing 2 phytases (A or B) and addressing previous limitations by including a broader/more practical range of phytase activity (250 or 1500 FTU/kg); providing 3 diets varying in calcium (Ca) and non-phytate phosphorus (nPP); and using an entire grow-out. Feeding diets lowest in Ca and nPP along with 1500 FTU/kg of A, B, or A+B resulted in improved broiler performance. Additionally, the use of A+B at 250 FTU/kg within diets of medium Ca and nPP levels demonstrated synergism through improved broiler performance and tibia ash. Overall, data suggest that the strategic utilization of enzyme combinations may provide additional benefits towards broiler production.

A series of experiments were conducted to evaluate the effects of dietary enzyme supplementation in broilers exposed to a live coccidia oocyst vaccine. In each experiment, Cobb 500 broilers were obtained at day of hatch from a commercial hatchery. Half of the chicks were sprayed with Coccivac BTM and housed in battery brooders in experiment (EXP) 1 and 2 or floor pens (EXP 3). Experimental diets were formulated according to Cobb 500 nutrient recommendations (positive control; PC) with the exception of Ca and available P (aP), which were reduced in the negative control (NC) diets approximately 0.1% (EXP 1), 0.11 and 0.13%, respectively (EXP 2), and 0.13% (EXP 3). Negative control diets in EXP 1 were supplemented with phytase (PHY), protease (PRO), xylanase (XYL), and the combination of PHY+PRO, PHY+XYL, and PHY+PRO+XYL. Negative control diets in EXP 2 were supplemented with PHY A, PHY B, and PHY C. In EXP 3, PC diets were supplemented with PHY at 1000 FTU/kg, and NC diets were supplemented with PHY at 1000 or 5000 FTU/kg. In all three experiments PHY supplementation generally improved (P ≤ 0.05) broiler performance and bone ash. Vaccination reduced (P ≤ 0.05) broiler performance in EXP 1 and 3, but increased (P ≤ 0.05) broiler performance in EXP 2. Xylanase and/or PHY supplementation tended to improve (P = 0.10) ileal amino acid digestibility (IAAD) in vaccinated broilers in EXP 1 and EXP 3. Phytase supplementation improved (P ≤ 0.05) IAAD and vaccination reduced (P ≤ 0.05) IAAD in EXP 3. Small intestinal morphology and goblet cell numbers were affected by enzyme supplementation and vaccination, which resulted in significant (P ≤ 0.05) interactions. In general, vaccination increased (P ≤ 0.05) small intestinal crypt depth and reduced (P ≤ 0.05) goblet cell numbers in EXP 3. Phytase supplementation of the NC diets fed to vaccinated broilers ameliorated the reduction in ileal goblet cells associated with vaccination (EXP 3). Enzyme supplementation tended to improve nutrient digestibility and altered small intestinal morphology in vaccinated broilers. Vaccination reduced broiler performance but nutrient digestion and dietary enzymes may improve nutrient utilization during a coccidia vaccination. / Ph. D.

Two experiments were conducted to determine the effects of various phytase concentrations on broiler growth performance, carcass composition, phosphorus digestibility, tibia ash and phosphorus utilization. The first experiment contained a positive control (PC) diet that was sufficient in all nutrients, a diet reduced in available phosphorus, calcium, amino acids and energy utilized as a negative control (NC) diet and the NC diet supplemented with two different phytase products at three inclusions (500, 1000, and 2000 FTU/kg) all fed to broilers over a 42-day period. The NC fed birds resulted in reduced growth performance by 42 days of age and phytase at 500 and 1000 FTU/kg had increased growth performance compared to NC (P<0.01), resulting in a similar response to the PC fed birds (P>0.05) indicating phosphorus and other nutrient release from the NC diet with phytase supplementation. Birds fed a diet supplemented with phytase A at 2000 FTU/kg outperformed the PC fed birds in body weight gain, feed efficiency, cold carcass weight, breast weight, breast yield, breast + tender weight and yield (P<0.01), but 2000 FTU/kg of phytase B resulted in poor responses often not improved in comparison to the NC fed birds (P>0.05). The second experiment utilized a standard curve to evaluate the use of phytase at various concentrations over a 14 day feeding assay. There were no differences between the two phytase treatments (500 and 2000 FTU/kg) in body weight gain, feed efficiency, feed intake or tibia ash weight (P>0.05). Standard curve analysis of tibia ash weight resulted in an estimate of 0.15 phytate phosphorus release from both phytase treatments. At 14 days, birds fed a treatment supplemented with phytase at 2000 FTU/kg showed an increase in apparent ileal phosphorus digestibility in comparison to 500 FTU/kg fed birds. The data may suggest that birds are digesting more phosphorus at an inclusion of 2000 FTU/kg phytase than 500 FTU/kg phytase but are not able to effectively utilize or store the nutrient as tibia ash showed similar mineral deposition between the two treatments. The concentration of non-phytate (nPP) in the Experiment 2 was 0.20% nPP (0.30% nPP in Experiment 1), which might have precluded the growth performance effects noted in Experiment 1. These two experiments indicate that phytase can act as a viable method in supplementing phosphorus and has the potential to increase broiler growth performance but results may vary depending on the phosphorus deficiency status of the diets before phytase supplementation. / Master of Science

Three experiments were conducted to determine the efficacy of an <i>Escherichia coli</i> 6-phytase (Quantum phytase) in laying hens fed corn-soybean meal based diets. In experiment 1, the Escherichia coli 6-phytase (Quantum) was evaluated for its efficacy in a 40-wk laying hen production trial. A total of 1080 White Leghorn hens were fed mash corn-soybean meal (CSM) based diets containing 0.35%, 0.25% or 0.15% of non-phytate phosphorus (NPP) with the 0.25% and 0.15% diets containing 200, 400 and 600 U/kg of exogenous phytase. Only minor differences in production characteristics were found between the 0.35% and 0.25% treatments regardless of phytase addition, indicating that 0.25% NPP resulted in P intake that was at or above the hens requirement. In contrast, the hens fed the 0.15% NPP diet without phytase supplementation had significantly reduced production performance in comparison to the 0.35% treatment. The addition of phytase to the 0.15% diet improved these production characteristics to levels equal to or better than the 0.35% diet. The results indicated that Quantum phytase was efficacious in CSM-based diets fed to White Leghorn laying hens and can be used to reduce the need for diet supplementation with inorganic phosphorus. In experiment 2, the effect of Quantum phytase on nutrient digestibility and bone ash in laying hens fed CSM-based diets was investigated. A total of 108 White Leghorn hens were fed CSM-based diets containing 0.35%, 0.25% or 0.15% NPP with the 0.25% and 0.15% diets containing 200, 400 or 600 U/kg of exogenous phytase. A linear reduction in phytate digestibility, ileal protein digestibility and soluble P was reported with increasing levels of exogenous phytase in the 0.25% diet. Tibial bone ash percentage was higher in 61-wk-old hens fed 0.25% diets supplemented with 200 or 400 U/kg phytase. Overall, the Quantum phytase was not efficacious in improving nutrient digestibility in laying hens fed CSM-based diets deficient in NPP. In experiment 3, the impact of dietary Ca and P level on the efficacy of an E. coli-derived 6-phytase and the apparent digestibility of various nutrients was investigated in White Leghorn laying hens fed CSM-based diets. A total of 384 White Leghorn hens were fed CSM-based diets containing four levels of Ca (2.5, 3.5, 4.5 or 5.5%), two levels of NPP (0.15 or 0.30%), and two levels of phytase (300 or 600 U/kg feed). Increasing dietary Ca caused a decrease in AMEn, duodenal protein digestibility, Ca and phytate digestibility, percentage soluble P in feces and the percentage of poor quality eggs, while significantly increasing bone ash and hen-housed and hen-day egg production. The higher level of NPP (0.30%) decreased AMEn, fecal protein, Ca and P digestibility, and hen-housed and hen-day egg production, while increasing fecal soluble P and egg specific gravity in comparison to the lower NPP level. The higher level of dietary phytase (600 U/kg feed) significantly increased AMEn, phytate and P digestibility, soluble P in feces, and hen-day and hen-housed egg production, while significantly reducing the percentage of soft shelled, cracked and broken eggs. Overall, dietary phytase, Ca and NPP levels, either as main effects or in an interactive manner, can affect apparent nutrient digestibility and production traits in laying hens fed CSM-based diets.

Three experiments were conducted to determine the efficacy of an <i>Escherichia coli</i> 6-phytase (Quantum phytase) in laying hens fed corn-soybean meal based diets. In experiment 1, the Escherichia coli 6-phytase (Quantum) was evaluated for its efficacy in a 40-wk laying hen production trial. A total of 1080 White Leghorn hens were fed mash corn-soybean meal (CSM) based diets containing 0.35%, 0.25% or 0.15% of non-phytate phosphorus (NPP) with the 0.25% and 0.15% diets containing 200, 400 and 600 U/kg of exogenous phytase. Only minor differences in production characteristics were found between the 0.35% and 0.25% treatments regardless of phytase addition, indicating that 0.25% NPP resulted in P intake that was at or above the hens requirement. In contrast, the hens fed the 0.15% NPP diet without phytase supplementation had significantly reduced production performance in comparison to the 0.35% treatment. The addition of phytase to the 0.15% diet improved these production characteristics to levels equal to or better than the 0.35% diet. The results indicated that Quantum phytase was efficacious in CSM-based diets fed to White Leghorn laying hens and can be used to reduce the need for diet supplementation with inorganic phosphorus. In experiment 2, the effect of Quantum phytase on nutrient digestibility and bone ash in laying hens fed CSM-based diets was investigated. A total of 108 White Leghorn hens were fed CSM-based diets containing 0.35%, 0.25% or 0.15% NPP with the 0.25% and 0.15% diets containing 200, 400 or 600 U/kg of exogenous phytase. A linear reduction in phytate digestibility, ileal protein digestibility and soluble P was reported with increasing levels of exogenous phytase in the 0.25% diet. Tibial bone ash percentage was higher in 61-wk-old hens fed 0.25% diets supplemented with 200 or 400 U/kg phytase. Overall, the Quantum phytase was not efficacious in improving nutrient digestibility in laying hens fed CSM-based diets deficient in NPP. In experiment 3, the impact of dietary Ca and P level on the efficacy of an E. coli-derived 6-phytase and the apparent digestibility of various nutrients was investigated in White Leghorn laying hens fed CSM-based diets. A total of 384 White Leghorn hens were fed CSM-based diets containing four levels of Ca (2.5, 3.5, 4.5 or 5.5%), two levels of NPP (0.15 or 0.30%), and two levels of phytase (300 or 600 U/kg feed). Increasing dietary Ca caused a decrease in AMEn, duodenal protein digestibility, Ca and phytate digestibility, percentage soluble P in feces and the percentage of poor quality eggs, while significantly increasing bone ash and hen-housed and hen-day egg production. The higher level of NPP (0.30%) decreased AMEn, fecal protein, Ca and P digestibility, and hen-housed and hen-day egg production, while increasing fecal soluble P and egg specific gravity in comparison to the lower NPP level. The higher level of dietary phytase (600 U/kg feed) significantly increased AMEn, phytate and P digestibility, soluble P in feces, and hen-day and hen-housed egg production, while significantly reducing the percentage of soft shelled, cracked and broken eggs. Overall, dietary phytase, Ca and NPP levels, either as main effects or in an interactive manner, can affect apparent nutrient digestibility and production traits in laying hens fed CSM-based diets.

Two experiments were undertaken to assess the dietary effects of microbial phytase on growth performance, mineral utilization, and immune responses in groupers, Epinephelus coioides. Basal diet contained fish meal and soybean meal as protein source and no phosphorus supplement. In experiment I, test diets containing 0 (0.2% sodium phosphate was supplemented; 0+P), 200, 400, 600, 800 FTU phytase/ kg were assigned to triplicate tanks and were fed for 12wk. Fish fed diet containing 0+P or 400 FTU phytase/kg showed better weight gains. Supplementation of phytase had no effect on feed efficiency, body tissue proximate composition, vertebral ash, and vertebra and whole-body phosphorus concentrations. Phosphorus utilization was improved and excretion tended to reduce for fish fed diets containing 400 and 600 FTU phytase/kg than the other treatments. Experiment II evaluated the effects of phytase supplementation on utilization of phosphorus, zinc and iron, and relative immune responses of the groupers. Three diets were formulated base on the results of experiment 1 to contain 0, 0+P or 400 FTU phytase/kg. The results of the 8-wk feeding trial indicated that phosphorus, zinc and iron utilizations were higher for fish fed diet containing inorganic phosphorus (0+P) than the phytase-containing diet. Phytase supplementation did not significantly affect immune responses. The present results indicated that phytase at the dosage of 400 FTU/kg is a suitable level in grouper diets, which would increase utilization and lessen excretion of dietary phosphorus.