Influence of phytase and xylanase supplementation of a wheat-based diet on ileal and total tract digestibility in growing pigs

The effect of phytase and xylanase supplementation of a wheat-based pig diet on the ileal and total tract apparent digestibility of dietary components and minerals were studied in eight growing pigs fitted with a PVTC cannula in a randomized block design experiment. The diets (A and B) were similar in major ingredient composition and in nutrient content. In diet A, part of the limestone was replaced with di-calcium phosphate to increase the content of available phosphorus (P). Diet B was fed without or with supplementation with phytase (500 FTU/kg; diet BP), xylanase (4000 XU/kg; diet BX) and phytase + xylanase (500 FTU and 4000 XU/kg; diet BPX). There were no differences (P > 0.05) between diets in the ileal or total tract digestibility of organic matter (OM), NDF and crude protein (CP). The ileal and total tract digestibility for P and Ca differed (P < 0.05) between diets, while there were no treatment effects for Zn. The ileal and total tract digestibility for P and Ca was higher (P < 0.05) on diets BP and BPX than on the other diets. In conclusion, phytase improved the utilization of dietary P and Ca in a wheat-based diet, while xylanase had no additional benefits in terms of OM and CP digestibility or mineral utilization. Phytase had no effect on the digestibility of OM, CP or NDF.     

Corn expressing an Escherichia coli-derived phytase gene: a proof-of-concept nutritional study in pigs

Two experiments were conducted to investigate the concept that the addition of corn expressing an Escherichia coli-derived gene (corn-based phytase; CBP) to a P-deficient diet would improve growth performance and P utilization in pigs. An E. coli-derived microbial phytase (expressed in Pichia pastoris) sprayed onto a wheat carrier (Quantum) was included for comparison. In Exp. 1, forty-eight 10-kg pigs were blocked by BW into 6 blocks and allotted to 8 dietary treatments such that the BW among dietary treatments was similar and given free access to feed for 28 d. The dietary treatments were a negative control (NC) with no inorganic P supplementation; NC + 2, 4, or 6 g of monosodium phosphate/kg; NC + 16,500, 33,000, or 49,500 phytase units (FTU) of CBP/kg; and NC + 16,500 FTU of Quantum/kg. In Exp. 2, twenty-four 13-kg barrows were assigned to the NC, NC + 16,500 or 33,000 FTU of CBP/kg, or NC + 16,500 FTU of Quantum/kg, in a nutrient- and energy-balance study consisting of 5 d of adjustment and 5-d collection periods. The total collection method was used to determine nutrient and energy balance. Addition of CBP to the low-P NC diet linearly increased (P < 0.01) ADG, G:F, and plasma P concentration of pigs during the 28-d study. There was no difference in ADG, G:F, or plasma P concentration between pigs fed the CBP or Quantum phytase at 16,500 FTU/kg. Weight gain, G:F, and plasma P concentration of pigs increased (P < 0.01) with monosodium phosphate supplementation, confirming P deficiency of the NC diet. Linear improvements (P < 0.05) in DM digestibility and energy retention were observed with CBP supplementation of the NC diet. Although there were linear (P < 0.01) and quadratic (P < 0.05) increases in N digestibility, N retention was unaffected by CBP supplementation of the NC diet in growing pigs. Phosphorus and Ca digestibilities and retentions improved linearly and quadratically (P < 0.01) with the addition of CBP to the NC diet. There was no difference in digestive utilization of P or Ca between pigs fed CBP and Quantum phytase at 16,500 FTU/kg. The data showed that the addition of a corn expressing an E. coli-derived gene to a P-deficient diet improved growth performance and indices of P utilization in pigs, and corn expressing phytase was as efficacious as Quantum phytase when supplemented in P-deficient diets for weanling pigs.     

The effects of supplementary bacterial phytase on dietary true metabolisable energy, nutrient digestibility and endogenous losses in precision fed turkeys

1. A total of 40 female BUT9 turkeys were used in a precision-feeding assay to investigate the effect of dietary phytase on true metabolisable energy corrected for N retention (TME(N)), coefficients of true dry matter (TDMD), mineral, amino acid and nitrogen (TND) digestibilities and the excretion of endogenous mucin, measured as sialic acid (SA). 2. Five treatments were used in this study: control (C), C + 250 phytase units (FTU) per kg feed, C + 500 FTU, C + 2500 FTU, and glucose only for endogenous losses estimation. Diets were formulated to be nutritionally adequate with the exception that the P content was relatively low (3·6 g/kg non-phytate P). 3. Inclusion of phytase increased TND in a quadratic manner with the optimum being achieved at approximately 500 FTU, at which TND was 37 % greater than in the control. The concentration of SA in the excreta decreased linearly with increased phytase supplementation. Dietary TME(N), TDMD and true mineral digestibility coefficients were not significantly affected by phytase supplementation. 4. Phytase inclusion increased digestibility coefficients for indispensable, dispensable and total amino acids in a linear manner. The scale of the response to phytase was greatest with threonine and least with lysine digestibility, suggesting a specific mechanism of action that benefits gut health. 5. The strong negative relationship between secretion of SA and threonine digestibility suggests that a large part of the threonine benefit may be from reduced mucin synthesis. This supports the hypothesis that dietary phytase may play a role in improving the health status of the intestine and, as a result, reduces the maintenance energy requirements of turkeys.     

Effect of graded doses and a high dose of microbial phytase on the digestibility of various minerals in weaner pigs

An experiment with 224 weaner pigs (initial BW of 7.8 kg) was conducted to determine the effect of dose of dietary phytase supplementation on apparent fecal digestibility of minerals (P, Ca, Mg, Na, K, and Cu) and on performance. Four blocks, each with 8 pens of 7 pigs, were formed. Eight dietary treatments were applied to each block in the 43-d experiment: supplementation of 0 (basal diet), 100, 250, 500, 750, 1,500, or 15,000 phytase units (FTU) or of 1.5 g of digestible P (dP; monocalcium phosphate; positive control) per kilogram of feed. The basal diet, with corn, barley, soybean meal, and sunflower seed meal as the main components, contained 1.2 g of dP per kilogram of feed. Fresh fecal grab samples were collected in wk 4 and 5 of the experiment. Average daily feed intake, ADG, G:F, and digestibility of all of the minerals increased (P < 0.001) with increasing phytase dose. Digestibility of P increased from 34% in the basal diet to a maximum of 84% in the diet supplemented with 15,000 FTU, generating 1.76 g of dP per kilogram of feed. At this level, 85% of the phytate phosphorus was digested, compared with 15% in the basal diet. Compared with the basal diet, digestibility of the monovalent minerals increased maximally at 15,000 FTU, from 81 to 92% (Na) and from 76 to 86% (K). In conclusion, phytase supplementation up to a level of 15,000 FTU/kg of a dP-deficient diet improved performance of weaner pigs and digestibility of minerals, including monovalent minerals. Up to 85% of the phytate-P was digested. Thus, dietary phytase supplementation beyond present day standards (500 FTU/kg) could further improve mineral use and consequently reduce mineral output to the environment.     

小麦日粮中木聚糖酶和植酸酶对肉仔鸡生长和养分消化率的影响

432只艾维因肉仔鸡用于研究小麦基础日粮中添加木聚糖酶(320FXU/kg)或添加750U/kg植酸酶降低日粮中0.08％的非植酸磷后,对生长性能、日粮表观代谢能、粗蛋白和植酸磷表观消化率的影响。试验结果表明:无论是单一添加木聚糖酶或植酸酶,还是同时添加这两种酶,都能提高1-6周龄肉仔鸡的增重和饲料转化率,降低死亡率。添加木聚糖酶可提高肉仔鸡小麦日粮的表观代谢能2.14％,增加氮的存留量2.58％。750U/kg的植酸酶完全可以降低肉仔鸡小麦日粮中0.08％非植酸磷。添加植酸酶的处理组可提高植酸磷的表观消化率43.25％,减少植酸磷排泄量55.0％。植酸酶和木聚糖酶对全期饲料转化率和植酸磷的表观消化率表现有明显的正互作效应(P<0.05)。     

Effects of varying levels of phytase supplementation on dry matter and phosphorus digestibility in horses fed a common textured ration

This study examines the effect of phytase supplementation on dry matter and phosphorus digestibility in mature horses. Four mature sedentary quarter horse geldings were used in a 4 × 4 Latin square design experiment. Horses were fed at 2% of the group's average body weight. The experimental diets consisted of textured concentrate of rolled corn, oats, and soybean meal fed in a 50:50 ratio with native prairie grass hay. The treatments were as follows: (1) control (0) with no phytase added to the basal ration, (2) 300 FTU/kg added to the basal ration, (3) 600 FTU/kg added to the basal ration, and (4) 900 FTU/kg added to the basal ration. During the 72-hour collections, total urine and feces were collected. Feed samples were also collect randomly throughout the trial. Feed and fecal sample were analyzed for dry matter, phosphorus, calcium, and magnesium. Urine samples were analyzed for phosphorus, calcium, and magnesium. There was no significance difference in dry matter intake, fecal output, dry matter digestibility, and urinary output across all diets (P > .05). Phosphorus digestibility was not improved with the addition of supplemental phytase (P > .05). The failure to observe an improvement in phosphorus digestibility may be because of the high levels of phosphorus in the diets. Further research needs to be conducted using diets with lower levels of phosphorus.     

Supplementation of carbohydrases or phytase individually or in combination to diets for weanling and growing-finishing pigs

The overall objective of the studies reported here was to evaluate the growth and nutrient utilization responses of pigs to dietary supplementation of phytate- or nonstarch polysaccharide-degrading enzymes. In Exp. 1, growth performance and nutrient digestibility responses of forty-eight 10-kg pigs to dietary supplementation of phytase or a cocktail of xylanase, amylase, and protease (XAP) alone or in combination were evaluated. The growth response of one hundred fifty 23-kg pigs to dietary supplementation of phytase or xylanase individually or in combination was studied in Exp. 2 in a 6-wk growth trial, whereas Exp. 3 investigated the nutrient digestibility and nutrient retention responses of thirty 24-kg pigs to dietary supplementation of the same enzymes used in Exp. 2. In Exp. 1, the pigs were used in a 28-d feeding trial. They were blocked by BW and sex and allocated to 6 dietary treatments. The treatments were a positive control (PC) diet; a negative control (NC) diet marginally deficient in P and DE; NC with phytase added at 500 or 1,000 phytase units (FTU)/kg; NC with xylanase at 2,500 units (U)/kg, amylase at 400 U/kg, and protease at 4,000 U/kg; and NC with a combination of phytase added at 500 FTU/kg and XAP as above. In Exp. 2 and 3, the 5 dietary treatments were positive control (PC), negative control (NC), NC plus 500 FTU of phytase/kg, NC plus 4,000 U of xylanase/kg, and NC plus phytase and xylanase. In Exp. 1, low levels of nonphytate P and DE in the NC diet depressed (P < 0.05) ADG of the pigs by 16%, but phytase linearly increased (P < 0.05) ADG by up to 24% compared with NC. The cocktail of XAP alone had no effect on ADG of pigs, but the combination of XAP and phytase increased (P < 0.05) ADG by 17% compared with the NC treatment. There was a linear increase (P < 0.01) in Ca and P digestibility in response to phytase. In Exp. 2, ADG was 7% greater in PC than NC (P < 0.05); there were no effects of enzyme addition on any response. In Exp. 3, addition of phytase alone or in combination with xylanase improved (P < 0.05) P digestibility. Phosphorus excretion was greatest (P < 0.01) in the PC and lowest (P < 0.05) in the diet with the combination of phytase and xylanase. The combination of phytase and xylanase improved P retention (P < 0.01) above the NC diet to a level similar to the PC diet. In conclusion, a combination of phytase and carbohydrases improved ADG in 10-kg but not 23-kg pigs, but was efficient in improving P digestibility in pigs of all ages.     

Effects of Source of Inorganic Phosphorus and Phytase Supplementation on Performance, Physiological Parameters and Bone Mineralization in Broilers

The objective of this study was to eval- uate the effects of inorganic phosphorus source and phytase addition on performance, nutrient digestibility and bone mineralization in broiler chickens. In Exp. 1,150 two-day old, male broiler chicks were fed a corn-soybean meal basal diet supplemented with phos- phorus provided by dicalcium phosphate, tricalcium phosphate or defluorinated rock phosphate. Five cages containing 10 birds were allotted to each of the three treatments. In Exp. 2,120 three-day old, male broiler chicks were fed the basal diet from Exp. 1 supplemen- ted with 0,250,500 ,or 1,000 P-＇rU phytase per kg of diet. Six cages containing five chicks were allotted to each of the four treatments. In Exp. 1, there was no difference in weight gain, feed intake or feed conver- sion as a result of feeding the different sources of in- organic phosphorus. The digestibility of phosphorus was significantly lower （P =0.01 ） for chicks fed di- ets supplemented with tricalcium phosphate than for chicks fed the other two diets. However, despite the lower digestibility, serum phosphorus levels did not differ among the three treatments. For Exp. 2, feedconversion showed a linear improvement （P = 0.03 ） with increasing levels of phytase inclusion （ days 0 to 33 ）. Phytase supplementation resulted in linear increa- ses in the digestibility of dry matter （P = 0.02 ）, crude protein （ P --- 0.04 ） and energy （ P 〈 0.01 ）. Chicks fed 1,000 FTU/kg phytase had significantly higher bone calcium （ P = 0.05 ） and bone breaking strength （P = 0.04 ） than chicks fed the basal diet on day 33. In conclusion, the results of the current study indicated that the performance of birds fed diets sup- plemented with dicalcium phosphate, tricalcium phos- phate or defluorinated phosphate was similar and therefore production costs could be lowered by choo- sing the cheapest inorganic phosphorus source when formulating diets for poultry. When diets were formu- lated to meet dietary phosphorus requirements, the growth of broilers was not enhanced with phytase sup- plementation. However, increases in feed conversion and bone breaking strength and its potential to impact culling and mortality in broiler operations may be suf- ficient justification for the routine inclusion of phytase in diets fed to broilers.     

Effects of Source of Inorganic Phosphorus and Phytase Supplementation on Performance, Physiological Parameters and Bone Mineralization in Broilers

The objective of this study was to evaluate the effects of inorganic phosphorus source and phytase addition on performance, nutrient digestibility and bone mineralization in broiler chickens. In Exp. 1, 150 two-day old, male broiler chicks were fed a corn-soybean meal basal diet supplemented with phosphorus provided by dicalcium phosphate, tricalcium phosphate or defluorinated rock phosphate. Five cages containing 10 birds were allotted to each of the three treatments. In Exp. 2, 120 three-day old, male broiler chicks were fed the basal diet from Exp. 1 supplemented with 0, 250, 500, or 1,000 FTU phytase per kg of diet. Six cages containing five chicks were allotted to each of the four treatments. In Exp. 1, there was no difference in weight gain, feed intake or feed conversion as a result of feeding the different sources of inorganic phosphorus. The digestibility of phosphorus was significantly lower (P = 0.01) for chicks fed diets supplemented with tricalcium phosphate than for chicks fed the other two diets.  However, despite the lower digestibility, serum phosphorus levels did not differ among the three treatments. For Exp. 2, feed conversion showed a linear improvement (P = 0.03) with increasing levels of phytase inclusion (days 0 to 33).  Phytase supplementation resulted in linear increases in the digestibility of dry matter (P = 0.02), crude protein (P = 0.04) and energy (P < 0.01).  Chicks fed 1,000 FTU/kg phytase had significantly higher bone calcium (P = 0.05) and bone breaking strength (P = 0.04) than chicks fed the basal diet on day 33. In conclusion, the results of the current study indicated that the performance of birds fed diets supplemented with dicalcium phosphate, tricalcium phosphate or defluorinated phosphate was similar and therefore production costs could be lowered by choosing the cheapest inorganic phosphorus source when formulating diets for poultry. When diets were formulated to meet dietary phosphorus requirements, the growth of broilers was not enhanced with phytase supplementation.  However, increases in feed conversion and bone breaking strength and its potential to impact culling and mortality in broiler operations may be sufficient justification for the routine inclusion of phytase in diets fed to broilers.     

Effect of microbial phytase on production performance of White Leghorn layers fed on a diet low in non-phytate phosphorus

1. An experiment with 150 White Leghorn layers was conducted to examine the effect of microbial phytase supplementation of low non-phytate phosphorus (NPP) diets on egg production, eggshell quality, bone mineralisation and retention of nutrients at 32-48 weeks of age. 2. Four isonitrogenous and isocaloric diets were formulated to contain 1.2, 1.8, 2.4 and 3.0 g NPP/kg diet with the two lowest NPP (1.2 and 1.8) supplemented with microbial phytase (Biofeed Phytase, India) at 500 FTU per kg diet. Each diet was offered ad libitum to 5 replicates of 5 layers throughout the experiment. 3. Body weight gain was reduced significantly in the layers fed on the 1.2 g/kg NPP diet as compared to those given diets containing 1.8-3.0 g/kg. Addition of phytase to the 1.2 g/kg diet significantly enhanced the body weight and was comparable with those given diets containing 1.8-3.0 g/kg NPP. 4. No additional advantage resulted from enhancing the NPP levels beyond 1.8 g/kg or adding phytase to a diet containing 1.8 g/kg NPP. 5. Hen d egg production, food intake, food efficiency, shell weight, shell thickness, shell strength and tibia strength followed the same trends as above. However, adding phytase to the 1.8 g/kg NPP diet significantly enhanced tibia ash. Egg weight, specific gravity and Haugh units were influenced by neither NPP concentration nor phytase supplementation. 6. Adding phytase to the 1.2 g/kg NPP diet significantly enhanced nitrogen and phosphorus retention. 7. It was concluded that addition of 500 FTU of microbial phytase/kg diet can allow the reduction of NPP content to 1.2g/kg in the layer diet, eliminate inorganic phosphorus supplementation and results in significant reduction of nitrogen and phosphorus excretion without affecting the production performance of layers.     

Effect of super dosing of phytase on growth performance,ileal digestibility and bone characteristics in broilers fed corn–soya‐based diets

A feeding trial was designed to assess the effect of super dosing of phytase in corn–soya‐based diets of broiler chicken. One hundred and sixty‐eight day‐old broilers were selected and randomly allocated to four dietary treatment groups, with 6 replicates having 7 chicks per treatment group. Two‐phased diets were used. The starter and finisher diet was fed from 0 to 3 weeks and 4 to 5 weeks of age respectively. The dietary treatments were consisted of normal phosphorus (NP) group without any phytase enzyme (4.5 g/kg available/non‐phytin phosphorus (P) during starter and 4.0 g/kg during finisher phase), three low‐phosphorus (LP) groups (3.2 g/kg available/non‐phytin P during starter and 2.8 g/kg during finisher phase) supplemented with phytase at 500, 2500, 5000 FTU/kg diet, respectively, to full fill their phosphorus requirements. The results showed that super doses of phytase (at 2500 FTU and 5000 FTU/kg) on low‐phosphorus diet improved feed intake, body weight gain, ileal digestibility (serine, aspartic acid, calcium, phosphorus), blood P levels and bone minerals such as calcium (Ca), P, magnesium (Mg) and zinc (Zn) content. It could be concluded that super doses of phytase in low‐phosphorus diet were beneficial than the normal standard dose (at 500 FTU/kg) of phytase in diet of broiler chicken.     

Influence of phytase added to a vegetarian diet on bone metabolism in pregnant and lactating sows

The purpose of the study was to find out if the supplementation of phytase to a diet of gestating and lactating sows has any effects on performance and bone parameters of the animals. Forty primiparous gilts were assigned into four groups: group A with phytase [4.2 g total phosphorus (P)/kg (gestation) and 4.5 g total P/kg (lactation)], group B without phytase (with phytase supplementation in diet for rearing) and same P content as group A, group C without phytase and higher P contents [5.0 g total P/kg (gestation) and 5.5 g total P/kg (lactation)] and group D with the same diet as group B (no phytase during the rearing). A 6-phytase was used in this trial (750 FTU/kg diet). The four diets were fed during gestation and lactation. Faeces were collected to determine apparent digestibility of minerals. Blood samples were taken to analyse minerals and bone markers. After weaning the sows were slaughtered and the bones of one hind leg were prepared to measure bone mineral density (BMD) and bone mineral content (BMC) of the tibia. Bone ash and mineral content of the phalanx III were determined. Mean P concentrations in serum decreased during gestation and lactation. But there were no significant differences between the groups. Bone formation marker bone-specific alkaline phosphatase decreased at the beginning of lactation whereas bone resorption marker serum crosslaps increased. The BMD and BMC of the tibia were slightly higher in the groups fed higher concentrations of P and phytase. The ash and mineral contents of the phalanx were the highest for the group fed the highest concentration of P. The apparent digestibility of P increased during gestation mostly in group A (57%--> 69%). In conclusion, high P content and addition of phytase to the diet induced a slightly higher ash content of the bones. It is of high importance, that sows during gestation absorb enough P, to avoid lamenesses and sudden fractures. As not many studies with phytase have been performed during gestation and lactation in sows yet, we can recommend, that phytase as supplement can be used to keep P in the diet at a lower level without negative consequences for bone health.     

Efficacy and equivalency of an Escherichia coli-derived phytase for replacing inorganic phosphorus in the diets of broiler chickens and young pigs

Two studies were conducted to determine the efficacy of an Escherichia coli-derived phytase (ECP) and its equivalency relative to inorganic phosphorus (iP) from monosodium phosphate (MSP). In Exp. 1, one thousand two hundred 1-d-old male broilers were used in a 42-d trial to assess the effect of ECP and iP supplementation on growth performance and nutrient digestibility. Dietary treatments were based on corn-soybean meal basal diets (BD) containing 239 and 221 g of CP, 8.2 and 6.6 g of Ca, and 2.4 and 1.5 g of nonphytate P (nPP) per kg for the starter and grower phases, respectively. Treatments consisted of the BD; the BD + 0.6, 1.2, or 1.8 g of iP from MSP per kg; and the BD + 250, 500, 750, or 1,000 phytase units (FTU) of ECP per kg. Increasing levels of MSP improved gain, gain:feed, and tibia ash (linear, P < 0.01). Increasing levels of ECP improved gain, gain:feed, tibia ash (linear, P < 0.01), apparent ileal digestibility of P, N, Arg, His, Phe, and Trp at d 21 (linear, P < 0.05), and apparent retention of P at d 21 (linear, P < 0.05). Increasing levels of ECP decreased apparent retention of energy (linear, P < 0.01). Five hundred FTU of ECP per kg was determined to be equivalent to the addition of 0.72, 0.78, and 1.19 g of iP from MSP per kg in broiler diets based on gain, feed intake, and bone ash, respectively. In Exp. 2, forty-eight 10-kg pigs were used in a 28-d trial to assess the effect of ECP and iP supplementation on growth performance and nutrient digestibility. Dietary treatments consisted of a positive control containing 6.1 and 3.5 g of Ca and nPP, respectively, per kg; a negative control (NC) containing 4.8 and 1.7 g of Ca and nPP, respectively, per kg; the NC diet plus 0.4, 0.8, or 1.2 g of iP from MSP per kg; and the NC diet plus 500, 750, or 1,000 FTU of ECP per kg. Daily gain improved (linear, P < 0.05) with ECP addition, as did apparent digestibility of Ca and P (linear, P < 0.01). Five hundred FTU of ECP per kg was determined to be equivalent to the addition of 0.49 and 1.00 g of iP from MSP per kg in starter pigs diets, based on ADG and bone ash, respectively.     

Effect of dietary inulin and phytase on mineral digestibility and tissue retention in weanling and growing Swine

The effect of dietary phytase and the prebiotic inulin on apparent mineral digestibility, bone mineralization, and tissue mineral contents was evaluated in weanling and growing pigs. In Exp. 1, inulin and phytase were incorporated in a 2 × 3 factorial arrangement of treatments with 8 replicate pens per treatment in a randomized complete block design. There were 2 levels of phytase [0 and 1000 phytase units (FTU)/kg] and 3 levels of chicory inulin (0, 3, and 6%). Weanling pigs (17 d of age; 5 or 4 pigs per pen) with an initial BW of 6.0 ± 0.6 kg were evaluated for 35 d postweaning. Macromineral digestibility was calculated using chromic oxide as an index in fecal samples collected during the final week of the experiment in replicates 1 through 4. On d 36, 1 pig per pen was killed and the heart, liver, kidney, and left tibia were excised and weighed. Inulin did not have any effect on growth performance measurements. Phytase increased (P < 0.05) BW on d 35 and ADG and ADFI during the 21-to-35-d and 0-to-35-d periods. Inulin did not result in increased tissue mineral concentrations on a per unit (mg/kg) or total tissue basis. Phytase increased (P < 0.05) the concentration of Zn in the liver, Mn and Zn in the heart, and Mg and Mn in the kidney. Phytase also increased (P < 0.05) total P, Mg, S, Mn, Se, and Zn in the liver as well as tibia ash. Phytase increased the digestibility of Ca (P < 0.01) and P (P < 0.05). Experiment 2 was conducted with growing pigs (initial BW, 41 ± 5 kg) to evaluate 2 levels of inulin (0 or 6%) and 2 levels of phytase (0 or 1000 FTU/kg) in a 2 × 2 factorial with 6 replicates in a randomized complete block design. Total urine and feces were collected for 10 d from each of 24 barrows after a 21-d acclimation period. Inulin inclusion resulted in reduced Ca digestibility (P < 0.05). Phytase increased (P < 0.05) the digestibility of both Ca and P. These results indicate that dietary inulin does not affect the overall mineral status or growth performance of pigs, whereas phytase increases the utilization of Ca and several microminerals, in addition to P, and also increases growth performance. Inulin and phytase do not appear to interact to affect pig growth or mineral status.     

Effect of increasing supplemental phytase concentration in diets fed to Hubbard × Cobb 500 male broilers from 1 to 42 days of age

Phytase supplementation beyond the standard doses used for phosphorus release has been reported to result in extraphosphoric effects by enhancing nutrient digestibility resulting in improved performance of broilers. A study was conducted to examine the effects of the progressive addition of an enhancedEscherichia Coli phytase (400–1,600 phytase units; FTU) on growth performance and carcass characteristics from 1 to 42 d of age in male broilers. One thousand four hundred Hubbard × Cobb 500 1-d-old chicks were randomly distributed into 56 floor pens (0.08 m²/bird). Seven dietary treatments were provided in a 3-phase feeding program consisting of (1) a positive control (adequate Ca and nonphytate P; PC); (2) 1 negative control (Ca and nonphytate P reduced by 0.14% and 0.13%; NC); (3 to 6) the NC diet with 4 increasing supplemental phytase concentrations (NC + 400 FTU, NC + 800 FTU, NC + 1,200 FTU, and NC + 1,600 FTU, respectively); and (7) a low-energy NC diet without phytase and xylanase (reduced 66 kcal of AME_n/kg). Body weight gain, feed conversion, mortality, weight and yield of whole carcass, abdominal fat, and pectoralis major and minor muscles were evaluated. Progressive supplementation of phytase decreased cumulative FCR linearly. Broilers fed diets containing 1,600 FTU had heavier total breast meat by 49 g compared with birds receiving the PC diets. Broilers consuming the NC + 400 FTU or the low-energy NC diet had similar growth performance and meat yield compared with birds provided PC diet. These data indicated that phytase supplementation beyond the need for phosphorus enhances growth performance and carcass characteristics.     

Effect of reduced energy, protein and entire substitution of inorganic phosphorus by phytase on performance and bone mineralisation of laying hens

1. The objective of this study was to evaluate the effects of total removal of dietary inorganic phosphorus and reduced energy and protein, without and with phytase supplementation, on the performance, egg quality and bone composition of laying hens. 2. Lohmann pink-shell hens were randomly assigned at 56 weeks of age to 5 treatments for 20 weeks as follows: (1) a positive control (PC) with 155 g CP/kg, 11·09 MJ ME/kg, calcium (Ca) 3·40% and non-phytic phosphorus (NPP) 0·26%, (2) a negative control (NC1) diet based on PC diet with Ca decreased to 3·30% and NPP to 0·14%, (3) NC2 diet was formulated on the basis of NC1 diet with 152·7 g CP/kg, 10·90 MJ/kg, (4) NC1 and (5) NC2 supplemented with phytase (300 FTU/kg) each. 3. Feed intake, hen-day or hen-housed egg production, egg number per hen-housed, and final body weight were depressed with NC1 and NC2 diets, but restored by phytase inclusion. There were no significant differences between the dietary treatments for feed conversion efficiency, rates of cracked and broken eggs, egg-shell thickness or egg-shell strength. Mortality was significantly increased by NC2 diet without phytase. Tibia ash was significantly decreased by both NC1 and NC2 diets. Bone strength, and Ca and P contents in tibia ash were significantly increased by phytase inclusion in the NC1 diet. 4. In conclusion, the NC1 and NC2 diets significantly depressed performance and tibia quality, but the addition of phytase (300 FTU/kg) significantly improved performance and tibia integrity.     

Nutrient utilization and manure P excretion in growing pigs fed corn-barley-soybean based diets supplemented with microbial phytase

The effect of high levels of microbial phytase supplementation in diets for growing pigs was studied in a 2‐week performance and nutrient digestibility trial involving 28 growing pigs weighing 16.4 ± 1.06 (mean ± SD) kg. Seven corn‐barley‐soybean meal‐based diets consisting of a positive control (PC) formulated to meet or exceed NRC nutrient requirements; a negative control (NC) with non‐phytate P reduced by 0.1% unit from NRC requirement and fed without or with 500 or 1000 U/kg; a doubled negative control (DNC) with no added inorganic P and fed without or with 2000 or 4000 U/kg. Chromic oxide was added as an indigestible marker and all diets were fed as mash. Pigs fed the PC diet had a higher P digestibility compared with those fed the NC (P < 0.02) and the DNC (P < 0.001) diets. Supplementing the NC diet with pyhtase tended to improve P digestibility (P < 0.10). However, addition of phytase to the DNC diet resulted in linear (P < 0.001) and quadratic (P < 0.03) increases in P digestibility with an overall improvement of 8% and 121% at 4000 phytase U/kg of diet, respectively, compared with the PC and DNC diets. Apparent total tract digestibility of N, OM and DM were higher (P < 0.05) in the PC diet compared with the DNC diet, but not the NC diet (P < 0.10). No effect of phytase addition to NC was observed on Ca, N, DM and OM digestibility. Phytase addition to the DNC diet resulted in a linear increase (P < 0.05) in N, DM and OM digestibility but not Ca. Increasing the levels of phytase supplementation in the NC and the DNC diets linearly decreased fecal P (P < 0.05) content by 45 and 42%, respectively. Adding phytase at 1000 or 4000 U/kg increased P retention (P < 0.05) by 14.3 or 15.6% units, respectively, compared with the PC diet. Urinary P excretion was higher in the group fed the PC diet compared with those fed the NC and DNC diets (P < 0.05). The results of this study show that complete removal of inorganic P from growing pig diets coupled with phytase supplementation improves digestibility and retention of P and N, thus reducing manure P excretion without any negative effect on pig performance.     

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.     

Effects of different dietary phytase activities on the concentration of antioxidants in the liver of growing broilers

One‐hundred and fifty male chickens were used to evaluate the effects of different activities (0, 250, 500, 12 500 FTU/kg) of phytase on their performance and antioxidant concentration in the liver. The chicks were housed in 30 cages and were allocated to six replicates of five dietary treatments. All diets were formulated to be adequate in energy and protein (12.90 MJ/kg metabolizable energy, 214 g/kg crude protein), however, the negative control (NC) was lower in available P compared with the positive control (PC) (2.5 vs. 4.5 g/kg diet). The other three diets were the NC supplemented with phytase at 250, 500 and 12 500 FTU/kg (NC + 250, NC + 500 and NC + 12 500 FTU respectively). The concentration of antioxidants in the liver of the birds was determined using HPLC at 21 days of age. Low P diets (NC) reduced weight gain, however, supplementation with phytase improved weight gain to the extent that it was better than the PC at the 12 500 FTU treatment (p < 0.05). Feed conversion ratio was also improved by the high level of phytase supplement more than other treatments (p < 0.05). Feed consumption was not affected either by dietary phosphorus concentration or by different phytase supplementation. The antioxidant data showed that the unsupplemented diet with low phosphorus (NC) decreased the concentration of coenzyme Q₁₀ and retinol‐linoleate in the liver compared with that of birds on the adequate phosphorus treatment (PC). Phytase supplementation, especially at the higher doses (500 and 12 500 FTU) increased the level of coenzyme Q₁₀ to the same level as the PC treatment. In addition, the highest dose (12 500 FTU) of phytase increased retinol concentration in the liver of chickens compared with those on the NC treatment. The highest inclusion level of phytase increased the α‐tocopherol level in the liver compared with the lower levels of phytase (NC + 250 and NC + 500 FTU).     

中性植酸酶在豆粕型饲料中替代磷酸二氢钙对花鲈生长及磷代谢的影响

本文旨在研究豆粕型饲料中用中性植酸酶替代不同水平的磷酸二氢钙,对花鲈(Lateolabrax japonicus)生长和磷代谢及利用的影响。以(2.52±0.01)g的花鲈为试验对象,用中性植酸酶分别替代试验用的豆粕型饲料中60%(PE6)、80%(PE8)和100%(PET)的磷酸二氢钙,每个替代水平饲料中分别设置1000FTU/kg(PE610,PE810,PET10)和1500FTU/kg(PE615,PE815,PET15)2个梯度。8周的养殖试验结果显示,在豆粕型饲料中用中性植酸酶替代磷酸二氢钙后,对各试验组花鲈的生长、鱼体成分和蛋白质消化率均无显著影响(P>0.05);但PE615和PE815组的干物质消化率显著高于对照组(P<0.05),PE815组的脂肪消化率显著高于PE610、PET10和PET15组(P<0.05),而PE615和PE815的总磷消化率显著高于对照组、PE610组和PET15组的(P<0.05)。各试验组的总磷摄入量、表观磷的摄入量、粪磷和非粪磷的排出量均随试验料中磷酸二氢钙添加量的减少而显著降低(P<0.05),而除PE610和PE815以外的各试验组的总磷储积率却显著高于对照组(P<0.05)。根据本试验的结果,在含有30.5%豆粕的花鲈饲料中添加一定量的中性植酸酶同时减少磷酸二氢钙的添加量后,仍能显著提高饲料中磷的消化和利用(P<0.05)。中性植酸酶的添加量以1000FTU/kg饲料为宜,其作用相当于12g/kg的磷酸二氢钙。