Dietary Phytase Research Articles

Effect of Phytase Supplementation on Rumen Fermentation Characteristics and Phosphorus Balance in Lactating Dairy Cows

This study aimed to evaluate the effects of exogenous phytase on rumen fermentation characteristics, the phosphorus (P)-flow at the duodenum and the P-balance in lactating dairy cows. For this purpose ruminal and duodenally fistulated cows were assigned to one of three dietary treatments: high P (HP) diet (n=7) provided a total of 45 g/d of P, archived by a supplementation of dicalcium phosphate to the diet; low P (LP) diet (n=5) provided 34 g/d of P without supplementation; LP+phytase (LP+PHY) diet (n=5) provided 34 g/d of P supplemented with an exogenous phytase. Dry matter intake and milk yield were recorded daily. In the first week of a sampling period P-balance was determined. Samples of ruminal fluid were taken and duodenal chyme was collected in the second sampling week. Ruminal pH and the concentration of volatile fatty acids were not different between the treatments. The HP-group shows a higher P-flow at the duodenum than other groups. No differences in apparent total tract P-digestibility were found between the treatments. The P-balance in the HP-group (2.6 g/d) was higher compared to the LP (-3.2 g/d) and LP+PHY (-3.0 g/d) group. Overall, phytase supplementation had no effect on P-digestibility in lactating dairy cows.

Fitase em dietas para frangos de corte de 1 a 21 dias alojados em ambientes com diferentes sistemas de climatização

O experimento foi conduzido para avaliar o efeito da inclusão de diferentes níveis de fitase nas dietas de frangos de corte, alojados em ambientes com e sem nebulização, sobre as variáveis de desempenho, incorporação de proteína bruta, cálcio e fósforo na carcaça e os teores de nitrogênio, cálcio e fósforo na cama das aves no período de um a 21 dias de idade. Foram alojados 640 pintainhos em boxes distribuídos uniformemente em dois galpões, ambos equipados com ventiladores e apenas um continha nebulizadores. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 5 x 2, cinco níveis de fitase: 0; 1000; 2000; 3000 e 4000 FTU/kg de ração, associados a dois ambientes (galpão com ventilação e nebulização e galpão com ventilação sem nebulização), quatro repetições e 16 aves por unidade experimental. As aves receberam dietas isonutritivas à base de milho e farelo de soja, formuladas para atender as exigências nutricionais, exceto para fósforo disponível, que foi reduzido em 20% da exigência. O ambiente com ventilação e nebulização melhora o ganho de peso, a viabilidade da criação e o índice de eficiência produtiva, além de aumentar a incorporação de proteína bruta e fósforo na carcaça. A suplementação de fitase até 4000 FTU/kg em dietas com redução de 20% do fósforo disponível aumenta o ganho de peso, o índice de eficiência produtiva e a incorporação de proteína bruta na carcaça, e reduz os teores de fósforo na cama.

Suplementação dietética de fitase na metabolização de nutrientes nas fases inicial e crescimento de frangos de corte em estresse por calor

The experiments were conducted to evaluate the effect of different inclusion levels of phytase in diets on the apparent metabolizable energy corrected for nitrogen balance, metabolization coefficient of dry matter, intake, excretion and coefficient of apparent retention of nitrogen, calcium and phosphorus in broilers under heat stress in initial and growth stages. Birds were distributed in a randomized block design and treated with five levels of phytase (0, 1000, 2000, 3000 and 4000 FTU/kg diet) and five replicates. Isonutrient diets based on corn and soybean meal, fed on chickens were formulated to meet nutritional requirements, except for available phosphorus, which was reduced in 20 % of requirement. Each experimental period lasted eight days, four for adaptation of poultry cages and diets and four for collection of excreta. Diet supplemented with phytase reduced apparent metabolizable energy corrected for nitrogen balance and decrease phosphorus excretion of birds under heat stress, initial and growth stages.

Dietary phosphorus and phytase and performance of broiler chickens from day 22 to 49 posthatch

Dietary phosphorus and phytase and performance of broiler chickens from day 22 to 49 posthatch

Phytate in pig and poultry nutrition.

Phosphorus (P) is primarily stored in the form of phytates in plant seeds, thus being poorly available for monogastric livestock, such as pigs and poultry. As phytate is a polyanionic molecule, it has the capacity to chelate positively charged cations, especially calcium, iron and zinc. Furthermore, it probably compromises the utilization of other dietary nutrients, including protein, starch and lipids. Reduced efficiency of utilization implies both higher levels of supplementation and increased discharge of the undigested nutrients to the environment. The enzyme phytase catalyses the stepwise hydrolysis of phytate. In respect to livestock nutrition, there are four possible sources of this enzyme available for the animals: endogenous mucosal phytase, gut microfloral phytase, plant phytase and exogenous microbial phytase. As the endogenous mucosal phytase in monogastric organisms appears incapable of hydrolysing sufficient amounts of phytate-bound P, supplementation of exogenous microbial phytase in diets is a common method to increase mineral and nutrient absorption. Plant phytase activity varies greatly among species of plants, resulting in differing gastrointestinal phytate hydrolysis in monogastric animals. Besides the supplementation of microbial phytase, processing techniques are alternative approaches to reduce phytate contents. Thus, techniques such as germination, soaking and fermentation enable activation of naturally occurring plant phytase among others. However, further research is needed to tap the potential of these technologies. The main focus herein is to review the available literature on the role of phytate in pig and poultry nutrition, its degradation throughout the gut and opportunities to enhance the utilization of P as well as other minerals and nutrients which might be complexed by phytates.

The effects of concurrent supplementation of dietary phytase, citric acid and vitamin D3 on growth and mineral utilization in juvenile yellow catfish Pelteobagrus fulvidraco

This experiment was conducted to evaluate the combined effects of phytase, citric acid and vitamin D 3 on the digestibility coefficients, growth performance, body composition, and vertebral and serum mineral contents in juvenile yellow catfish ( Pelteobagrus fulvidraco ). The study used 1200 juvenile yellow catfish in a completely randomized design with a 2 × 2 × 2 factorial arrangement (0 and 500 IU phytase kg − 1 feed, 0 and 2 g citric acid kg − 1 feed, and 2000 and 4000 IU vitamin D 3 kg − 1 feed). Triplicate groups of 50 fish with an initial single body weight of 3 g ± 0.0 g per tank were fed to satiety for eight weeks. 500 IU phytase kg − 1 feed addition significantly increased (P < 0.05) the apparent digestibilities of dry matter and phosphorous (P), whole body sodium (Na), P, calcium (Ca), magnesium (Mg) and zinc (Zn) retention, and vertebral P, Ca and Zn deposition. However, phytase did not enhance the growth response of juvenile yellow catfish. The addition of 2 g citric acid kg − 1 feed significantly increased (P < 0.05) weight gain (WG) and specific growth rate (SGR), and significantly decreased (P < 0.05) feed conversion ratio (FCR). High levels of vitamin D 3 significantly increased (P < 0.05) whole body Na, K, P, Ca, Mg and Zn retention while no difference in vertebral mineral deposition, the apparent digestibility of dry matter, P and protein, or growth performance between low and high levels of vitamin D 3 supplementation was observed. In addition, no significant interactions were observed among or between phytase, citric acid and vitamin D 3 on the growth or mineral utilization of juvenile yellow catfish. • 500 IU kg − 1 phytase was enough to increase mineral utilization. • Citric acid improved growth performance even at low amount of 2 g kg − 1 diet. • No different effects of two doses of vitamin D 3 on growth performance • No interactions among or between phytase, citric acid and vitamin D 3 in growth and mineral utilization

Assessing changes in the composition of broiler litters from commercial poultry units in Northern Ireland following the adoption of phytase in diets

Microbial phytases increase the bioavailability of phytate P in poultry diets, and a survey was undertaken to determine if their use had lowered the P composition of broiler litter in Northern Ireland compared with standard values of litter composition listed in the current United Kingdom fertilizer recommendations. Litter samples were collected from a total of 20 units across Northern Ireland in 2010 and analyzed for DM, N, phosphate (P2 O5), potash (K2 O), magnesium oxide (MgO), water-soluble P (WSP), ammonium N (NH4 N), and uric acid N. Dry matter of litter was positively correlated (P < 0.001) with N (r2 = 0.65), P2 O5 (r2 = 0.63), K2 O (r2 = 0.56), and MgO (r2 = 0.58). Negative correlations were observed between litter DM and WSP (r2 = 0.45, P < 0.001) and NH4 N (r2 = 0.22, P = 0.038) contents. A standardized litter composition with a 60% DM gave a phosphate content of 13.7 kg/t that was 45% lower than the fertilizer book value (RB209), but there were only slight differences (<3%) between book values and DM standardized values for N and potash contents. Uric acid and NH4 contents were similar to published values. Mean N:P ratio (by weight) of litter increased from 3.7 in 2004 to 5.0 in 2010, lowering the risk of oversupply of P if land applications are targeted to meet N supply. Using the standard RB209 values to plan land applications of broiler litter to meet crop P demands risks undersupplying P, and there is a need for the regulatory values to be modified in light of the changing composition of broiler litter.

Effects of the Dietary Microbial Phytase Supplementation on Bioavailability of Phosphorus in Juvenile Olive Flounder Paralichthys olivaceus Fed Soybean Meal based Diets

An 8 weeks feeding trial was carried out to evaluate the effects of dietary microbial phytase (P) supplementation on nutrient digestibility, and body composition in juvenile olive flounder Paralichthys olivaceus fed soybean meal-based diets. Seven experimental diets were formulated to be isonitrogenous and isocaloric to contain 50.0% crude protein (CP) and 16.7 kJ of available energy/g with or without dietary phytase supplementation. White fish meal (FM) provided 92.4% of the total protein in the basal diet (S0), in the other 6 diets, 30% or 40% FM protein was replaced by soybean meal: 70% FM + 30% soybean meal (S30); 70% FM + 30% SM + 1000 U phytase/kg diet (S30P1000); 70% FM + 30% SM + 2000 U phytase/kg diet (S30P2000); 60% FM + 40% SM (S40); 60% FM + 40% SM + 1000 U phytase/kg diet (S40P1000); and 60% FM + 40% SM + 2000 U phytase/kg diet (S40P2000). After two weeks of the conditioning period, triplicate groups of 25 fish initially averaging 6.15 ± 0.04 g (mean ± S.D.) were randomly distributed into the aquarium and were fed one of the experimental diets for 8 weeks. After feeding trial, supplementation of phytase significantly improved the apparent digestibility coefficients of phosphorus in flounder diets ( P<0.05) containing 30% and 40% soybean meal regardless the levels. However, phytase had no significant influence on growth performance and whole body composition of fish. Based on the experimental results, we conclude that dietary supplementation of phytase could improve the apparent digestibility coefficient of phosphorus in olive flounder.

Scientific skepticism and new discoveries: An analysis of a report of zinc/phytase supplementation and the efficacy of botulinum toxins in treating cosmetic facial rhytides, hemifacial spasm and benign essential blepharospasm

Introduction: A recent paper in the Journal of Drugs in Dermatology by Koshy and colleagues (2012, 11():507–512) report on “Effect of Dietary Zinc and Phytase Supplementation on Botulinum Toxin Treatments” and conclude by claiming the discovery of “a potentially meaningful role for zinc and/or phytase supplementation in increasing the degree and duration of botulinum toxin effect in the treatment of cosmetic facial rhytids, benign essential blepharospasm, and hemifacial spasm”. The purpose of this paper is to examine these published claims for possible methodological and design errors and potential sources of bias. Methods: The authors evaluated the published results in comparison to the published literature on zinc deficiency, the role of phytase, prior reports of an effect of zinc on activity of botulinum toxin, issues of study design and execution and if the reported results of the study supported the study's conclusions. Results: Multiple issues are present in the reported study, which appear to invalidate its conclusions. These areas include lack of direct evidence for the presence of clinical or subclinical zinc deficiency in the study population or for the level of phytate in the study population sufficient to interfere with zinc absorption in these subjects. Additionally, there is ambiguity as to the actual dose of zinc used as well as in the study design itself. Also there is a failure of the study through the “unmasking” of the crossover design. There is potential financial conflict of interest in the study execution that may have biased the reported results. Finally there is inadequate data presented to evaluate the claims made of a “new discovery” as to the three disease entities reported on and the various botulinum toxins used in each of the three treatment arms of the study. Discussion: Based on this evaluation, it appears that a high level of clinical and scientific skepticism is warranted concerning any claim of a beneficial effect of zinc and phytase supplementation on the efficacy or potency of any botulinum toxins in the reported conditions.

Improvements in growth performance, bone mineral status and nutrient digestibility in pigs following the dietary inclusion of phytase are accompanied by modifications in intestinal nutrient transporter gene expression.

Phytase (PHY) improves growth performance, nutrient digestibility and bone structure in pigs; however, little is known about its effects on intestinal nutrient transporter gene expression. In the present study, a 44 d experiment was carried out using forty-eight pigs (11·76 (sem 0·75) kg) assigned to one of three dietary treatment groups to measure growth performance, coefficient of apparent ileal digestibility (CAID), coefficient of apparent total tract nutrient digestibility (CATTD) and intestinal nutrient transporter gene expression. Dietary treatments during the experimental period were as follows: (1) a high-P (HP) diet containing 3·4 g/kg available P and 7·0 g/kg Ca; (2) a low-P (LP) diet containing 1·9 g/kg available P and 5·9 g/kg Ca; (3) a PHY diet containing LP diet ingredients+1000 phytase units (FTU)/kg of PHY. The PHY diet increased the average daily gain (P< 0·05) and final body weight (P< 0·01) and decreased the feed conversion ratio (P< 0·05) compared with the LP diet. Pigs fed the PHY diet had a higher CAID of gross energy compared with those fed the HP and LP diets (P< 0·001). Pigs fed the PHY diet had increased CAID of P (P< 0·01) and CATTD of Ca and P (P< 0·001) compared with those fed the LP diet. The PHY diet increased the gene expression of the peptide transporter 1 (PEPT1/SLC15A1) (P< 0·05) in the ileum compared with the LP diet. The LP diet decreased the gene expression of the sodium-glucose-linked transporter 1 (SGLT1/SLC5A1) and GLUT2/SLC2A2 (P< 0·05) and increased the expression of membrane Ca channel (TRPV6) and calbindin compared with the HP diet (P< 0·001). In conclusion, feeding a diet supplemented with PHY improves growth performance and nutrient digestibility as well as increases the gene expression of the peptide transporter PEPT1.

Factors affecting arsenic and copper runoff from fields fertilized with poultry litter.

Arsenic (As) and copper (Cu) runoff from fields fertilized with poultry litter has received increasing attention in recent years, although it is not known if heavy metal runoff from poultry litter poses a significant threat to the environment. The objective of this study was to determine the main factors affecting As and Cu concentrations in runoff water from pastures receiving poultry litter applications. Rainfall simulation studies were conducted to determine the effects of the following treatments on metal runoff: (i) aluminum sulfate (alum) additions, (ii) diet modification using phytase or high available phosphorus corn, (iii) fertilizer type, (iv) poultry litter application rate, and (v) time until the first runoff event occurs after poultry litter application. Results showed that alum additions to poultry litter significantly decreased As and Cu concentrations in runoff water. Copper concentrations were highest in runoff from poultry litter from birds fed phytase diets compared with other diets; however, this effect may have been a result of wet storage conditions rather than diet. Triple superphosphate applications resulted in the lowest heavy metal concentrations in runoff water among all fertilizer treatments, while normal poultry litter resulted in the highest concentrations. Arsenic and Cu concentrations increased in runoff water as poultry litter application rates increased and decreased with increasing time until the first runoff event. These data indicate that adding alum to poultry litter, a cost-effective best management practice, which also results in lower P runoff and ammonia emissions, may also be an effective tool in reducing metal runoff.

Effect of dietary exogenous phytase on laying performance of chicken at older ages

A total of 48 Shaver-579 chicken layers aged between 85 to 94 weeks were reared in individual cages and given a basal diet amounting to 115g feed/bird/day. The basal diet fortified with 0.05, 0.10 or 0.15% Rena-Phytase-400 constituted of 3 experimental diets to see the effects of exogenous phytase on egg production and egg quality. Results indicated that increasing level of exogenous phytase in diet almost linearly (p&lt;0.05) increased egg production and feed conversion but did not affect egg quality. Providing phytase in the diet at 0.05, 0.10 and 0.15% increased egg production by 11.86, 22.2 and 24.58%, respectively. It was shown that highest egg production was found at 0.15% phytase levels in diet. It can be concluded that egg production of aged hen could be increased by adding said amount of exogenous phytase in the diet.DOI: http://dx.doi.org/10.3329/bjas.v43i1.19385 Bang. J. Anim. Sci. 2014. 43 (1): 52-55

Effects of step-up and step-down phytase regimens on performance and processing yields of male broilers from 1 to 35 d of age

An experiment was conducted to evaluate increasing or decreasing concentrations of dietary phytase on growth performance and processing yields of male broilers from 1 to 35 d of age. Treatments consisted of a positive control, a negative control (NC; less 0.14% Ca, 0.13% nonphytate P, and 0.03% Na), and 6 additional treatments based on the NC supplemented with phytase. Treatments 3 through 5 consisted of the NC diet supplemented with 500 phytase units (FTU)/kg of phytase in the starter phase that was either continued throughout the remainder of the study (treatment 3) or increased to 1,500 FTU/kg beginning in the finisher (treatment 4) or grower (treatment 5) phases. Treatment 6 had 1,500 FTU/kg of phytase throughout the study. Treatments 7 and 8 had 1,500 FTU/kg in the starter and decreased to 500 FTU/kg in the finisher or grower phases, respectively. At 35 d of age, broilers fed diets containing 1,500 FTU/kg of phytase had increased BW gain compared with birds fed diets formulated to contain 500 FTU/kg of phytase. Increasing phytase concentration between the starter and grower phases or decreasing phytase concentration between the grower and finisher phases negatively affected FCR from 1 to 35 d of age. Phytase supplementation did not affect weight and yield of carcass characteristics. Therefore, dietary phytase concentration should not be varied throughout production for optimum growth performance.

Effect of supplementing microbial phytase in diets containing graded concentrations of calcium on performance, shell quality and bone mineral parameters in WL layers

An experiment was conducted to study the effect of supplemental phytase in diets containing graded concentrations of calcium (Ca) and non-phytin phosphorus (NPP) on performance of WL layers. Eight diets with four graded concentrations of Ca (35, 37.5, 40 and 42.5gkg−1) and two concentrations of NPP (3 and 1gkg−1) were prepared. The low phosphorus diets were supplemented with phytase (500FYTkg−1). Each diet was fed ad libitum to 8 replicates consisting of 88 laying chickens each from 25 to 72 weeks of age. Data were compiled and analysed in 3 phases (phase 1, 25 to 40 weeks; phase 2, 41 to 56 weeks; phase 3, 56 to 72 weeks of age) and all the 3 phases as the overall period. The interaction between Ca concentration and phytase supplementation significantly influenced egg production (EP), feed intake (phase 1), egg weight (phase 3), egg mass (phase 2 and 3), feed efficiency (FE) and Ca and P concentrations in tibia ash at 44 weeks of age. Feed intake during phases 2 and 3, egg weight during phases 1 and 3, egg mass during phase 1, body weight during phases 1, 2 and overall period, egg shell defects, shell weight, shell percent and bone mineral parameters at 72 weeks of age were not affected by the interaction. EP, EM and FE improved significantly with increase in dietary Ca concentration from 35 to 37.5gkg−1 in groups fed without phytase and further improvement was not observed at higher concentrations of Ca in diet. While the layer performance in groups fed 35g Ca with phytase supplementation improved similar to those fed ≥37.5gCakg−1 diet without phytase. The layer performance reduced significantly in groups fed diets supplemented with phytase at higher concentrations of Ca (40 and 42.5gCakg−1) compared to those fed 35gCakg−1 suggesting the inhibitory effect of higher dietary Ca concentrations on utilization of phytase phosphorus. Based on the study, it is concluded that WL layers reared in open sided poultry houses in tropical climate require lower intake of Ca (3.32, 3.80 and 4.00gbird−1day−1) when the diets are supplemented with phytase (500FYTkg−1) compared to those fed without phytase (3.58, 4.14 and 4.30gbird−1day−1 during 25–40, 41–56 and 57–72 weeks of age, respectively, during phase 1–3). At higher concentrations of Ca (40 and 42.5gkg−1), response to supplemental phytase appears to be reduced in terms of performance in layers.

Combined effects of dietary phytase and organic acid on growth and phosphorus utilization of juvenile yellow catfish Pelteobagrus fulvidraco

This experiment was conducted to evaluate the combined effects of organic acid and phytase on the digestibility coefficients, growth performance, body composition, vertebral and serum mineral contents, and liver and serum antioxidant properties in juvenile yellow catfish. This experiment was conducted using 900 juvenile yellow catfish in a completely randomized design with a 3 × 2 factorial arrangement (0, 2, and 4 g kg− 1 feed organic acid and 0 and 0.2 g kg− 1 feed (1000 IU kg− 1 feed) phytase). Triplicate groups of 50 fish per tank were fed dietary treatments for eight weeks. Phytase addition increased the apparent digestibilities of dry matter, protein, and P; final body weight; specific growth rate; body crude ash; body crude protein; body P and Ca contents; and vertebral P and Ca contents; but decreased the fecal P content and feed conversion ratio. However, organic acid did not affect these parameters. Both dietary phytase and organic acid significantly reduced the blood reactive oxygen species (ROS) level, serum superoxide dismutase (SOD) activity, and catalase (CAT) activity. The addition of 4 g kg− 1 organic acid to the diet supplemented with 1000 IU kg− 1 phytase caused a significant interaction on the increments of blood ROS content and serum SOD and CAT activities, which indicated increasing oxidative stress (P < 0.05). Phytase and organic acid showed no significant interaction on growth performance, body composition, and utilization of efficiency of plant-protein-source P in juvenile yellow catfish (P > 0.05).

Increasing levels of phytase in diets formulated with reduced available phosphorus content supplied to male and female broilers

The reduction of the available phosphorus (avP) content in the broiler diet must be followed by the supplementation of adequate phytase. One experiment was conducted with broilers from 15 to 28 days of age to determine the level of necessary phytase when the mashed diet is formulated with 0.213% of avP to enable the results of performance, tibia ash content, and calcium (Ca) utilization similar to those determined for birds fed with diet formulated to meet their nutritional requirements. Thus, 120 broilers were distributed in (4+1) x2 factorial arrangement corresponding to four deficient diets in avP (0.213%) supplemented with phytase (0; 750; 1,500 or 2,250FTU kg-1) plus one positive control diet without phytase (0.426% of avP), supplied to male and female broilers. Males showed better performance and higher totalP retention. Decrease in the avP content of the diet without phytase use worsened the performance, tibia ash content, and Ca retention; however, these parameters were improved gradually with the increase of the phytase level in the diet. Regardless of sex, using 2,250FTU kg-1, it is possible to reduce the avP to 0.213% without impairing performance, tibia ash content, and Ca retention; in addition to reducing the totalP excretion in 56.75% and improving its utilization in 38.58%.

Effect of dietary phytase transgenic corn on physiological characteristics and the fate of recombinant plant DNA in laying hens.

The study aimed to evaluate the potential effects of feeding with phytase transgenic corn (PTC) on organ weight, serum biochemical parameters and nutrient digestibility, and to determine the fate of the transgenic DNA in laying hens. A total of 144 50-week-old laying hens were grouped randomly into 2 treatments, with 8 replicates per treatment and 9 hens per replicate. Each treatment group of hens was fed with diets containing 62.4% non-transgenic conventional corn (CC) or PTC for 16 weeks. The phytase activity for CC was 37 FTU/kg of DM, whereas the phytase activity for PTC was 8,980 FTU/kg of DM. We observed that feeding PTC to laying hens had no adverse effect on organ weight or serum biochemical parameters (p>0.05). A fragment of a poultry-specific ovalbumin gene (ov) was amplified from all tissues of hens showing that the DNA preparations were amenable to PCR amplification. Neither the corn-specific invertase gene (ivr) nor the transgenic phyA2 gene was detected in the breast muscle, leg muscle, ovary, oviduct and eggs. The digestibility data revealed no significant differences between the hens that received the CC- and PTC-based diets in the digestibility of DM, energy, nitrogen and calcium (p>0.05). Phosphorus digestibility of hens fed the PTC-based diet was greater than that of hens fed the CC-based diet (58.03% vs 47.42%, p<0.01). Based on these results, it was concluded that the PTC had no deleterious effects on the organ weight or serum biochemical parameters of the laying hens. No recombinant phyA2 gene was detected in muscle tissues and reproductive organs of laying hens. The novel plant phytase was efficacious in improving the phosphorus digestibility of laying hens.

Effect of Exogenous Phytase on the Phosphorus and Zinc Metabolism of Fattening Bulls

This study investigated the effects of exogenous phytase, different dietary phosphorus (P) and zinc (Zn) levels on the P- and Zn-metabolism of fattening bulls. 48 German Holstein bulls (average initial live weight 312 ± 49 kg) were used for a feeding trial and allocated to four dietary treatments, P/Zn, P+MIN/Zn, P/Zn+PHY and P/Zn+MIN. All bulls received a diet of 80 % corn silage and 20% concentrate on a dry matter (DM) basis. The corn silage intake was for ad libitum and the concentrate intake restricted. The concentrate of P+MIN/Zn was supplemented with dicalcium phosphate. The concentrate of the P/Zn+PHY group was supplemented with an exogenous phytase (0.1 g/kg DM in the diet, 50 000 FTU/g) and the concentrate of the P/Zn+MIN group was supplemented with Zn. The P- and Zn-concentration in the diet of the P/Zn-, P+MIN/Zn-, P/Zn+PHY- and P/Zn+MIN-groups were 2.41, 2.99, 2.48 and 2.41 g P/kg DM and 33.2, 33.6, 34.0 and 38.8 mg Zn/kg DM, respectively. No differences in P- and Zn-concentration of faeces, liver, testes and performance were observed between the treatments. In the Os metacarpale , P- and phytase supplementation resulted in a slightly higher P-concentration, while the Zn addition led to the lowest value ( P =0.062). Overall, it becomes clear that the microbial phytase of the rumen is sufficient enough to make the indigestible phytate-P and the hardly digestible Zn digestible for ruminants. The supplemented dietary phytase has no influence on the bioavailability of the mineral P and the trace element Zn.

Partição do P excretado nas fezes e urina de suínos em fase de crescimento, alimentados com dietas contendo diferentes níveis de enzima fitase

Este estudo teve como propósito avaliar a partição do P excretados nas fezes e urina de suínos em fase de crescimento, alimentados com dietas contendo diferentes níveis de inclusão de enzima fitase, através do uso do radioisótopo P-32. Foram utilizados 20 suínos, machos castrados, em delineamento de blocos ao acaso, com cinco tratamentos - 0; 250; 500; 750 e 1000UF/kg da ração - e quatro repetições. Os animais foram alojados em gaiolas metabólicas por 17 dias, sendo dez dias para adaptação e sete dias para coleta de fezes e urina. Amostras de sangue foram coletadas por cinco dias. No primeiro dia da fase experimental, cada animal recebeu por via endovenosa uma solução radioativa com 7,4MBq de 32P. O uso de fitase em dietas para suínos proporciona redução do P total e solúvel excretados nas fezes. Pode-se reduzir em 50% a suplementação de P por fosfato bicálcico nas dietas para suínos em crescimento, adicionando 500UF/kg de dieta, sem provocar prejuízos ao sistema fisiológicos dos animais.

Effects of Thermostable Phytase Supplementation on the Growth Performance and Nutrient Digestibility of Broilers

2 Abstract: A study was conducted to investigate the effects of thermostable phytase supplementation on the growth performance and nutrient digestibility of broilers for 42 d. 1-day-old Arbor Acres chicks with similar initial body weight were randomly divided into 3 treatments consisting 6 pens of 20 chicks per pen. The control group was given maize-soybean meal basal diet and the other two groups were fed the basal diet including either 500 U ordinary phytase/kg diet or 500 U thermostable phytase/kg diet. The results indicated that broilers given diets supplemented with thermostable phytase have increased body weight, body weight gain and feed intake than these fed basal diet (p<0.05). However, the same effect was only noted for body weight in ordinary phytase-supplemented group (p<0.05). Birds fed diet supplemented with thermostable phytase had enhanced crude protein utilization when compared with these given basal diet (p<0.05) but the same effect was not observed for broilers fed ordinary phytase-supplemented diet. As expected, dietary phytase supplementation significantly enhanced nitrogen-corrected apparent metabolizable energy of broilers (p<0.05) and this effect was more pronounced in the thermostable phytase-supplemented group. The results suggested that phytase supplementation, especially thermostable phytase supplementation, can improve the growth performance and nutrient utilization of broilers.