Phytases are a group of enzymes that hydrolyze the phospho-monoester bonds of phytates. Phytates are one of the major forms of phosphorus found in plant tissues. Fungi are mainly used for phytase ...production. The production of fungal phytases has been achieved under three different fermentation methods including solid-state, semi-solid-state, and submerged fermentation. Agricultural residues and other waste materials have been used as substrates for the evaluation of enzyme production in the fermentation process. Nutrients, physical conditions such as pH and temperature, and protease resistance are important factors for increasing phytase production. Fungal phytases are considered monomeric proteins and generally possess a molecular weight of between 14 and 353 kDa. Fungal phytases display a broad substrate specificity with optimal pH and temperature ranges between 1.3 and 8.0 and 37-67°C, respectively. The crystal structure of phytase has been studied in
. Notably, thermostability engineering has been used to improve relevant enzyme properties. Furthermore, fungal phytases are widely used in food and animal feed additives to improve the efficiency of phosphorus intake and reduce the amount of phosphorus in the environment.
•The novel consensus phytase variant completely compensated for the reduction in avP, Ca, Na, dig AA, and ME respectively at each dose-level.•The novel consensus phytase variant maintained growth ...performance, carcass characteristics, and bone quality of broilers fed wholly vegetable or conventional US type commercial diets through 42 days of age.•The novel consensus phytase variant supplementation could be used to lead to reduced feed cost and production benefit.
Two experiments were conducted to evaluate the effects of a novel consensus bacterial 6-phytase variant (PhyG) on performance of broilers fed US type diets with reduced nutrients and energy. Each experiment utilized a completely randomized block design where four treatments were tested with 10 replicate groups, each treatment totaling 270 day-of-hatch male Ross 308 broilers. The diets were: 1), a nutrient-adequate control (PC) and 2), a nutrient and energy-reduced negative control (NC): PC minus 0.19 % avP, 0.23 % Ca, 0.045 % Na, up to 0.05 % unit dig AA and 37 kcal/kg ME and 3), NC with PhyG supplemented at 1,500 FTU/kg (PhyG1500) 4), PC minus 0.164 % avP, 0.201 % Ca, 0.037 % Na, up to 0.035 %-unit dig. AA and 29 kcal/kg ME plus the PhyG at 750 FTU/kg (PhyG750). Xylanase was included in all diets at 750 XU/kg with 25 kcal/kg of ME matrix applied. Experiment 1 diets (wholly vegetable) were based on corn-soybean meal with <2 % DDGs. Experiment 2 diets (conventional) were based on corn-soybean meal with <3 % DDGS and <4 % meat and bone meal. Diets were pelleted and fed ad libitum over four phases: starter (1–10d), grower (11–21d), finisher 1 (22–35d), and finisher 2 (36–42d). In both experiments, compared with PC, birds fed the nutrient and energy reduced NC exhibited reduced 42d BW and increased overall 1–42d FCR (P < 0.05). During all phases, in both experiments, PhyG at each dose-level produced growth performance measures that were by phase and cumulatively equivalent to PC. PhyG at 1500 FTU improved accumulative FCR (1–21d, 1–35d and 1–42d) in experiment 1, and 1–21d FCR in experiment 2 compared to PC. Similarly, PhyG750 and PhyG1500 increased (P < 0.05) tibia ash and carcass yield vs. NC to similar levels as PC. For all measures, response values were numerically highest with 1500 FTU/kg. In conclusion, the novel consensus phytase variant completely compensated for the reduction in avP, Ca, Na, dig AA, and ME respectively at each dose-level and maintained growth performance, carcass characteristics, and bone quality of broilers fed wholly vegetable or conventional US type commercial diets through 42 days of age, leading to reduced feed cost and production benefit.
Abstract
The capacity of a novel bacterial 6-phytase variant (PhyG) to totally replace dietary supplemental inorganic phosphate (Pi) in broilers aged one day old was evaluated using a phased dosing ...strategy and reduction in dietary phytate. A total of 1,248 one-day-old Ross 308 broilers were assigned to 24 pens (52 birds/pen, 12 pens/diet, six each males and females) in a complete randomised block design with a 2×2 factorial arrangement (two diets, two genders). Diets comprised: (1) a positive control (PC) based on maize, wheat and soybean meal, containing Pi from monocalcium phosphate and 2,000 XU/kg xylanase, and; (2) an inorganic phosphate-free (IPF) diet equivalent to PC but with reduced Ca (-2.0 g/kg) and supplemented with PhyG at 3,000, 2,000 and 1000 FTU/kg from d 0 to 11 (3.4 g/kg phytate-P (PP)), d 11 to 22 (3.3 g/kg PP) and d 22 to 42 (2.8 to 2.9 g/kg PP), respectively. A negative control was not included for animal welfare reasons. Tibias were collected on d 11, 22 and 42 from two birds/pen. Treatment IPF maintained or improved average daily gain (ADG), average daily feed intake and feed conversion ratio (FCR) vs PC during all phases; Body weight was higher in the IPF treatment than the PC at d 42 (+3.97%, P<0.01) and ADG during d 0 to 42 (+4.10%, P<0.01). Overall (d 0 to 42), treatment IPF improved FCR in males (-5 points vs PC, P<0.05) but not females. Tibia ash was equivalent in IPF and PC throughout, with no gender differences. In conclusion, when applied as a phased dosing strategy to diets with graded reduction in PP content, PhyG totally replaced supplemental Pi during all growth phases in males and females.
Phytate (myo-inositol hexakisphosphate salts) can constitute a large fraction of the organic P in soils. As a more recalcitrant form of soil organic P, up to 51 million metric tons of phytate ...accumulate in soils annually, corresponding to ∼65% of the P fertilizer application. However, the availability of phytate is limited due to its strong binding to soils via its highly-phosphorylated inositol structure, with sorption capacity being ∼4 times that of orthophosphate in soils. Phosphorus (P) is one of the most limiting macronutrients for agricultural productivity. Given that phosphate rock is a finite resource, coupled with the increasing difficulty in its extraction and geopolitical fragility in supply, it is anticipated that both economic and environmental costs of P fertilizer will greatly increase. Therefore, optimizing the use of soil phytate-P can potentially enhance the economic and environmental sustainability of agriculture production. To increase phytate-P availability in the rhizosphere, plants and microbes have developed strategies to improve phytate solubility and mineralization by secreting mobilizing agents including organic acids and hydrolyzing enzymes including various phytases. Though we have some understanding of phytate availability and phytase activity in soils, the limiting steps for phytate-P acquisition by plants proposed two decades ago remain elusive. Besides, the relative contribution of plant- and microbe-derived phytases, including those from mycorrhizas, in improving phytate-P utilization is poorly understood. Hence, it is important to understand the processes that influence phytate-P acquisition by plants, thereby developing effective molecular biotechnologies to enhance the dynamics of phytate in soil. However, from a practical view, phytate-P acquisition by plants competes with soil P fixation, so the ability of plants to access stable phytate must be evaluated from both a plant and soil perspective. Here, we summarize information on phytate availability in soils and phytate-P acquisition by plants. In addition, agronomic approaches and biotechnological strategies to improve soil phytate-P utilization by plants are discussed, and questions that need further investigation are raised. The information helps to better improve phytate-P utilization by plants, thereby reducing P resource inputs and pollution risks to the wider environment.
Two studies were conducted to evaluate the effect of phytase supplementation on the overall performance and nutrient retention efficiency of rainbow trout (Oncorhynchus mykiss) fed low-phosphorus (P) ...plant-based diets at water temperatures of 11 °C and 15 °C. In the first experiment at 11 °C, trout (average weight 56 g) were allocated to one of 4 dietary treatments, with 3 replicate 200L tanks per diet and 35 fish per tank. In the second experiment (15 °C), trout (average weight 42 g) were allocated to one of 3 dietary treatments, with 3 replicate 200L tanks per diet and 34 fish per tank. Diets were fed to satiation over a 75 or 83 day period for experiment 1 and 2, respectively. Treatments included a low-P diet (NC), with no added monocalcium phosphate (MCP), supplemented with 0, 500 or 2500 FTU/kg phytase (Quantum Blue). Experiment 1 also included a diet adequate in P (PC) with 1.8% MCP inclusion. In both experiments, feeding phytase linearly increased (P < 0.01) weight gain of fish fed NC diets. Feeding phytase at 2500 FTU/kg improved weight gain of fish exposed to water temperatures of 11 °C and 15 °C by 36% and 45%, respectively, compared to the respective NC. Feed conversion ratio (FCR) was also improved (linear, P < 0.001) by 14% with phytase supplementation at 15 °C. At water temperatures of 11 °C, supplementing phytase to the NC diet improved N retention (P < 0.05) beyond that of the non-supplemented NC and PC diets. Furthermore, 2500 FTU/kg phytase increased P digestibility by 56 and 27 percentage points, and P retention by around 29 and 17 percentage points, compared to the NC and PC, respectively. Consequently, supplementing 2500 FTU/kg phytase reduced (linear, P ≤ 0.001) N and P excretion by 13% and 55%, respectively, compared to the PC. At 15 °C, addition of phytase to the low-P diet increased (quadratic, P < 0.017) N and P retention in trout by approximately 4 and 24 percentage points, respectively. Supplementing phytase to the low-P diet reduced N (linear, P ≤ 0.001) and P (Quadratic, P < 0.01) excretion in trout, with addition of 2500 FTU/kg lowering excretion of these nutrients by 19% and 42%, respectively. These findings demonstrate the efficacy of an enhanced Escherichia coli phytase, even at low water temperatures, to support performance of trout fed low-P diets, while enhancing P and protein utilization and lessening environmental pollution.
•Trout were fed plant-based diets deficient in non-phytate phosphorus, at water temperatures of 11 °C and 15 °C.•Phytase supplementation improved weight gain of trout fed low-phosphorus diets at 11 °C and 15 °C.•Phosphorus and nitrogen retention were enhanced by addition of phytase.•Findings suggest phytase as a tool for improving nutrient utilization and lessening environmental pollution.
A five week feeding study was carried out to assess the effects of phytase enzyme with different level of calcium and available phosphorus on Ross 308 broilers on performance, carcass traits and ...deposition of calcium and phosphorus on serum and tibia of broiler chickens. One hundred and sixty-eight one day-old Ross 308 broiler chicks were used. The birds were weighed and assigned to equal six treatment groups with fixed calcium to phosphorus ratio 2:1. Each two treatments have the same value of available phosphorus according feeding stage but one of them with supplementation of Hiphos GT (100gm/ton phytase enzyme unit FTU/Kg) and the other one without supplementation in a completely randomized design. Each treatment had four replicates and each replicate contains seven chicks. The results showed that phytase enzyme supplementation with available phosphorus 0.5% and 0.45% significantly elevated (P < 0.05) body weight, body weight gain and feed intake, and reduced (P < 0.05) feed conversion ratio in starter period. All parameters in grower, finisher period and overall showed non-significant for all groups. Moreover, the highest significant value from all other groups in liver enzymes Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum, founded in broilers fed the diet with phytase enzyme and available phosphorus 0.40% and without phytase enzyme in creatinine. Calcium value with available phosphorus 0.35% with phytase enzyme showed high significance. In Phosphorus we found that usage of phytase enzyme with available phosphorus 0.30% and 0.35% as same as 0.35% without phytase. In weight, eviscerated and dressing usage of phytase enzyme with available phosphorus 0.4% revealed the highest significant difference from all groups. Thigh, breast and drumstick value showed non-significant difference from all other groups.
Phytate and phytase in fish nutrition Kumar, V; Sinha, A. K; Makkar, H. P. S ...
Journal of animal physiology and animal nutrition,
June 2012, Letnik:
96, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Phytate formed during maturation of plant seeds and grains is a common constituent of plant‐derived fish feed. Phytate‐bound phosphorus (P) is not available to gastric or agastric fish. A major ...concern about the presence of phytate in the aquafeed is its negative effect on growth performance, nutrient and energy utilization, and mineral uptake. Bound phytate‐P, can be effectively converted to available‐P by phytase. During the last decade, phytase has been used by aqua feed industries to enhance the growth performance, nutrient utilization and bioavailability of macro and micro minerals in fish and also to reduce the P pollution into the aquatic environment. Phytase activity is highly dependent on the pH of the fish gut. Unlike mammals, fish are either gastric or agastric, and hence, the action of dietary phytase varies from species to species. In comparison to poultry and swine production, the use of phytase in fish feed is still in an unproven stage. This review discusses effects of phytate on fish, dephytinisation processes, phytase and pathway for phytate degradation, phytase production systems, mode of phytase application, bioefficacy of phytase, effects of phytase on growth performance, nutrient utilization and aquatic environment pollution, and optimum dosage of phytase in fish diets.
Cereals and pseudocereals are a rich source of nutrients and trace elements, but their dietary bioavailability is low due to the presence of phytate (IP6), an antinutritional compound with the ...ability to chelate cations and proteins. Phytase is an enzyme that catalyzes the hydrolysis of IP6 and it is used as an additive improving the nutritional quality of grain‐based foods. The aim of this study was to select lactic acid bacteria (LAB) isolated from pseudocereals with phytase activity, characterize their production and activity, and purify the enzyme. LAB strains isolated from grains and spontaneous sourdough of quinoa and amaranth were grown in the Man Rogosa and Sharpe medium where the inorganic phosphate (Pi) was replaced by 1% of IP6. Phytase activity was determined by measuring the Pi released from IP6. Phytase of Lactobacillus (L.) plantarum CRL1964 (PhyLP) showed the highest specific activity from 73 LAB evaluated. IP6 induces PhyLP production, which is at its maximum at the end of the exponential phase. PhyLP was thermostable and maintained its activity under acidic conditions. The enzymatic activity is stimulated by ethylenediaminetetraacetic acid, Co2+, and ascorbic acid. PhyLP was partially purified and showed a molecular mass of 55 kDa. L. plantarum CRL1964 and/or PhyLP have the potential to be included in the processing of cereal/pseudocereals based products for animal feed and/or the food industry improving its nutritional value.
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