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1.
《The Journal of Applied Poultry Research》2006,15(2):292-306
Soybean meal contains approximately 0.62% total P of which 0.4% can be phytate P, which is considered less biologically available for poultry than other forms of P. Soybean meal is a key ingredient in poultry feeds and information is needed about the range of phytate P and nonphytate P in different soybean meals. The phytate P content of soybeans may vary due to climatic conditions, soil type and soybean variety. Previous research has shown that phytate P can be hydrolyzed in the gastrointestinal tract providing available P by adding a commercial phytase enzyme to poultry feed. The extent of phytate hydrolysis by dietary supplementation of phytase has been shown to vary depending on the type of dietary ingredients such as corn, soybean meal, canola meal, and wheat. Research is needed to determine if different commercially available soybean meals respond in a similar manner to a feed added phytase. Twenty-five soybean meal samples were collected from active soybean crushing plants in the United States and 18 of the samples were selected to evaluate the effect of a microbial phytase on phytate P disappearance using 5-d bioassays. The range of analyzed values in soybean meal samples for total P, phytate P, Ca, protein, and neutral detergent fiber (NDF) were 0.59 to 0.87, 0.32 to 0.42, 0.28 to 0.54, 40.44 to 51.69, and 7.78 to 16.09%, respectively. Bioassay results indicate that body weight, feed consumption, and feed conversion ratio improved significantly (P < 0.05) in some of the groups fed diets with enzyme compared with groups fed the same diet with no added enzyme. The range of total P retention and phytate P disappearance for groups fed diets with no enzyme were 21.35 to 48.41 and 13.64 to 37.13%, respectively. The addition of phytase increased total P retention and phytate P disappearance from 56.81 to 68.62 and 76.18 to 94.08%, respectively. The results indicate no correlation among components (total P, phytate P, Ca, protein, and NDF) of soybean meal samples, percentage of phytate P disappearance, and percentage of total P retention for groups fed diets with and without added phytase. 相似文献
2.
Despite increasing practical experience and cascades of scientific reports on exogenous microbial phytases, several issues associated with their use remain unresolved because of the ambiguous and, at times, conflicting data that has been generated. One possible cause of these inconsistent outcomes is dietary calcium (Ca) levels, which are mainly derived from limestone. Thus the purpose of this review is to examine Ca interactions with dietary phytate and phytases, particularly exogenous, microbial phytases, and their consequences for poultry and pigs. The polyanionic phytate molecule has a tremendous capacity to chelate cations and form insoluble Ca–phytate complexes, which are refractory to phytase activity. Thus Ca–phytate complex formation along the gastrointestinal tract, where one phytate (IP6) molecule binds up to five Ca atoms, assumes importance and approximately one third of dietary Ca may be bound to phytate in digesta. Consequently, phytate limits the availability of both P and Ca as a result of insoluble Ca–phytate complex formation, the extent of which is driven by gut pH and molar ratios of the two components. It is accepted that Ca–phytate complexes are mainly formed in the small intestine where they have a substantial negative influence on the efficacy of mucosal phytase. However, exogenous phytases are mainly active in more proximal segments of the gut and lower pH levels, so their efficacy should not be influenced by Ca–phytate complexes in the small intestine. There is, however, data to indicate that Ca and phytate interactions occur under acidic conditions with the formation of soluble and insoluble Ca–phytate species, which could negatively impact on exogenous phytase efficacy. Also, Ca will tend to elevate gut pH because of limestone's very high acid binding capacity, which will favour Ca–phytate interactions and may influence the activity of exogenous phytases depending on their pH activity spectrum. The de novo formation of binary protein–phytate complexes that are refractory to pepsin hydrolysis may be fundamental to the negative impact of phytate on the digestibility of protein/amino acids. However, high dietary Ca levels may disrupt protein–phytate complex formation by interacting with both phytate and protein even at acidic pH levels, thereby influencing the outcomes of phytase amino acid digestibility assays. Finally, it is increasingly necessary to define the Ca and nonphytate-P requirements of pigs and poultry offered phytase-supplemented diets. 相似文献
3.
The present study gives an overview on the whole mechanism of phytate degradation in the gut and the enzymes involved. Based on the similarity of the human and pigs gut, the study was carried out in pigs as model for humans. To differentiate between intrinsic feed phytases and endogenous phytases hydrolysing phytate in the gut, two diets, one high (control diet) and the other one very low in intrinsic feed phytases (phytase inactivated diet) were applied. In the chyme of stomach, small intestine and colon inositol phosphate isomers and activities of phytases and alkaline phosphatases were determined. In parallel total tract phytate degradation and apparent phosphorus digestibility were assessed. In the stomach chyme of pigs fed the control diet, comparable high phytase activity and strong phytate degradation were observed. The predominant phytate hydrolysis products were inositol phosphates, typically formed by plant phytases. For the phytase inactivated diet, comparable very low phytase activity and almost no phytate degradation in the stomach were determined. In the small intestine and colon, high activity of alkaline phosphatases and low activity of phytases were observed, irrespective of the diet fed. In the colon, stronger phytate degradation for the phytase inactivated diet than for the control diet was detected. Phytate degradation throughout the whole gut was nearly complete and very similar for both diets while the apparent availability of total phosphorus was significantly higher for the pigs fed the control diet than the phytase inactivated diet. The pathway of inositol phosphate hydrolysis in the gut has been elucidated. 相似文献
4.
1. The study aimed to assess the effect of a commercially available microbial phytase on phytate phosphorus and total phosphorus content at the terminal ileum as well as true ileal amino acid digestibility. 2. Five diets, each containing a different plant-based feedstuff, were supplemented with microbial phytase and fed, along with a non-supplemented corresponding diet, to 28-d-old broiler chickens, Chromic oxide was used as an indigestible marker. Ileal contents were collected and analysed, along with the diets, for total phosphorus, phytate phosphorus and amino acids. 3. Endogenous phosphorus determined at the terminal ileum was 272 +/- 108 mg/kg food dry matter (mean +/- SE). Endogenous ileal amino acid flows ranged from 58 +/- 10 mg/kg food dry matter for methionine to 568 +/- 47 mg/kg food dry matter for glutamic acid. 4. Supplementation with microbial phytase resulted in a significantly greater phytate P disappearance from the terminal ileum for rice bran (17% units), but not for soyabean meal, maize, wheat or rapeseed meal. Similarly total phosphorus digestibility was significantly (P < 0.05) higher when microbial phytase was added to the rice-bran-based diet but not for any of the other feedstuffs. 5. Amino acid digestibility was significantly greater in the presence of microbial phytase for all the amino acids examined in wheat, for several of the amino acids each in maize and rapeseed meal and for one amino acid in rice bran and soyabean meal. The average increase in amino acid digestibility for those amino acids affected, was 13, 6, 10, 7 and 12% units for wheat, maize, rapeseed meal, rice bran and soyabean meal, respectively. 6. It appears that microbial phytase improves phosphorus digestibility and amino acid digestibility for certain plant-based feedstuffs. 相似文献
5.
K. Blaabjerg D. Carlson J. Hansen-Mller A.-H. Tauson H.D. Poulsen 《Livestock Science》2007,109(1-3):240
A series of in vitro experiments simulating liquid feeding were performed to evaluate the effect of microbial phytase addition, heat-treatment and soaking time on degradation of phytate and lower inositol phosphates when soaking compound wheat/soybean meal diets or the single feedstuffs wheat or soybean meal. The effect of phytase addition on phytate degradation was greatest in soybean meal, almost intermediate for wheat/soybean meal diets and not detectable in wheat, which might be due to a better accessibility to phytate in soybean meal compared with wheat. Heat-treatment seemed to enhance the accessibility between phytase and phytate, whereby phytate degradation was stimulated. Additionally, it was shown that wheat phytase is able to stimulate degradation of phytate in soybean meal. Independent of treatment, the amount of IP5–IP2 was extremely small in relation to phytate in both wheat and soybean meal, indicating that when one phosphate group is removed from the phytate complex, degradation of IP5–IP2 is completed. Consequently, it is anticipated that liquid feeding might result in a higher digestibility of plant P compared with dry feeding of pigs. 相似文献
6.
Rapp C Lantzsch HJ Drochner W 《Journal of animal physiology and animal nutrition》2001,85(11-12):414-419
Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (A. niger) were investigated with six minipigs (40-50 kg initial BW) fitted with re-entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5, and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2, and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet (43 U phytase/kg DM); (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM) and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 0730 and 1930 per animal 350 g diet mixed with 1050 ml de-ionized water were fed. Digesta were collected continuously and completely during 12 h after feeding. In the duodenal digesta, 70% of the microbial phytase (diet 2) and 45% of the wheat phytase (diet 3) were recovered within 12 h after ingestion of the phytases, whereas only negligible amounts were detected in the digesta of pigs fed the phytase-poor corn-based diet 1. Most phytase activity passed through the stomach within the first hour after feeding. Microbial phytase activity at pH 2.8 was less sensitive to acidic pHs, such as those found in the stomach, than phytase activity at pH 5.3. Phytase activities in the digesta of the distal ileum did not depend either on source or amount of dietary phytase activity. 相似文献
7.
The objective was to quantify the retention of digesta and evaluate the degradation of phytate or inositol hexakisphosphate (InsP(6)) and lower inositol phosphates (InsP?, InsP?, InsP?, and InsP?) in the stomach at different times after feeding pigs a fermented liquid diet with microbial phytase or a nonfermented diet with or without microbial phytase. Six barrows fitted with gastric cannulas were used. The experiment was a 3 × 3 Latin square with 3 pigs fed 3 diets during 3 wk in 2 replicates. Each experimental period lasted for 7 d, comprising 3 d of adaptation and 4 d of total collection of gastric digesta. For each pig, the digesta was collected once daily at 1, 2, 3, or 5 h after feeding the morning meal. A basal wheat- and barley-based diet was steam-pelleted at 90°C. The dietary treatments were a nonfermented basal diet (NF-BD), the NF-BD with microbial phytase (750 phytase units of phytase/kg, as-fed basis; NF-BD + phytase), and the NF-BD + phytase fermented for 17.5 h (F-BD + phytase). Gastric InsP?-P was not detected at all in pigs fed F-BD + phytase because of complete InsP? degradation during fermentation of the feed before feeding. Gastric InsP?-P decreased over time (P < 0.05) in pigs fed NF-BD and NF-BD + phytase. The decreases were 45, 54, 56, and 61 percentage points greater at 1, 2, 3, and 5 h, respectively, in pigs fed NF-BD + phytase compared with NF-BD. However, substantial amounts of InsP? still passed into the small intestine in pigs fed NF-BD + phytase, especially within the first hour (estimated to 17% of InsP?-P intake). The accumulation of lower inositol phosphates in gastric digesta was very small for all treatments and at all times because of a rapid and almost complete degradation. In conclusion, phytase addition to the nonfermented diet increased the degradation of gastric InsP?. However, considerable amounts of intact InsP? still passed into the small intestine because of a shortage of time for InsP? degradation in the stomach. Therefore, to increase the apparent digestibility of plant P in dry wheat- and barley-based diets, the development of phytases that can degrade InsP? effectively immediately after ingestion of the feed at an initial gastric pH from 6.5 to 5.0 is needed. Feeding F-BD + phytase compensated for the shortage of time because the InsP? degradation was completed during fermentation before feeding. The degradation of InsP? to InsP? is the bottleneck for plant P utilization in pigs because the degradation of the lower inositol phosphates is rapid and almost complete. 相似文献
8.
The effect of dietary phytate and phytase on carbohydrase activity and hexose transport was investigated in broiler chickens. Diets containing phytate P (2.2 or 4.4 g/kg) with different phytase dose rates (0, 500, or 1,000 phytase units/kg) were fed to 504 female Cobb chicks for 3 wk. Diets containing high phytate concentrations depressed (P < 0.05) BW and G:F, whereas phytase supplementation improved (P < 0.05) the performance of birds. In the duodenum, phytate decreased (P < 0.05) the activities of disaccharidases, Na(+)K(+)-ATPase, and glucose concentrations by 5 to 11%, but phytase enhanced (P < 0.05) the concentrations of amylase, sucrase, maltase, Na(+)K(+)-ATPase, and glucose by 5 to 30%. In the jejunum, phytate decreased (P < 0.05) the concentrations of amylase, sucrase, Na(+)K(+)-ATPase, and glucose by 10 to 22%, and phytase alleviated the negative effect of phytate on the above variables. Ingestion of diets containing phytate also decreased (P < 0.05) serum amylase activity and glucose concentration, and phytase enhanced (P < 0.05) serum concentrations of amylase, sucrase, maltase, Na(+)K(+)-ATPase, and glucose. There were also interactions (P < 0.05) between phytate and phytase on the concentrations of serum amylase, duodenal amylase, sucrase, and jejunal glucose. Enzymatic analysis at a molecular level showed that neither phytate nor phytase influenced the mRNA expression of sucrase-isomaltase in the small intestine. Also, the investigation into the sodium glucose cotransporter gene may challenge the mechanism by which phytate interferes with glucose utilization, as partly indicated by bird performance, and transmembrane transport because diets containing increased phytate upregulated (P < 0.05) the mRNA expression of the sodium glucose cotransporter gene in duodenum and did not influence it in the jejunum. These results indicate that phytate can impair endogenous carbohydrase activity and digestive competence, and phytase can ameliorate these effects for chickens. 相似文献
9.
Rapp C Lantzsch HJ Drochner W 《Journal of animal physiology and animal nutrition》2001,85(11-12):420-430
Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (Aspergillus niger) were investigated with six minipigs (40-50 kg initial body weight) fitted with re-entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5 and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2 and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet [43 U phytase/kg dry matter (DM)]; (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM); and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 07 30 h and 19 30 h, each animal was fed 350 g diet mixed with 1050 ml de-ionized water. Digesta were collected continuously and completely during a 12-h period after feeding. Mean hydrolysis rates of IP6 in the stomach as measured at the proximal duodenum of animals 1, 4, 5 and 6 were 9.0, 77.2 and 66.2% for diet 1, 2 and 3, respectively. Microbial phytase was much more effective in phytate hydrolysis than wheat phytase. Mean IP6 hydrolysis rates of the respective diets in the stomach and small intestine as measured at the distal ileum of animals 1, 2 and 3 were 19.0, 62.6 and 64.6% and were lower than treatment means of the stomach only. Differences existed between experimental animals with respect to their ability to hydrolyse IP6 in the stomach independent of the presence and source of dietary phytase. Considerable amounts of hydrolysis products occurred in both the duodenal and ileal digesta when diets 2 and 3 were fed; however, only traces were determined after ingestion of diet 1. Independent of dietary treatment, four IP5 isomers were detected, but in different amounts. 相似文献
10.
芽孢杆菌中性植酸酶基因的原核表达及酶学性质分析 总被引：1，自引：0，他引：1
植酸酶作为饲料添加剂能够有效提高动物对饲料中磷的利用率及减少粪便中磷排放对环境的污染,并降低植酸的抗营养作用。为了获得性能稳定的高活性植酸酶,采用PCR扩增芽孢杆菌(Bacillus sp.)中性植酸酶基因phyC(GenBank登录号:FJ986327)的成熟肽编码序列,将其克隆进原核表达载体pET-28a(+),并转化E.coli BL21(DE3)进行表达。在37℃条件下以0.5 mmol/L IPTG诱导4 h能够获得大量包涵体蛋白,在25℃条件下以0.5 mmol/L IPTG诱导6 h有利于可溶性蛋白的获得。利用Ni-NTA亲和层析柱纯化重组植酸酶产物,获得的中性植酸酶的部分酶学特性为:耐热性较好,最适反应温度55℃,在70℃处理10 min可保持20%以上的酶活性;耐酸、碱能力较强,最适pH 6.0～7.0,pH 5.5～9.0时能保持80%以上的酶活性,pH 5.0～10.0时处理60 min仍能保持70%以上的酶活性,在pH 2.0～4.0时能保持40%以上的酶活性。利用构建的切除芽孢杆菌中性植酸酶基因phyC信号肽编码序列的原核表达载体及优化的诱导表达条件,能够在大肠杆菌中高量表达性能稳定的芽孢杆菌中性植酸酶。 相似文献
11.
The objective of this study was to determine the functional location and disappearance of activity of a supplemental Escherichia coli AppA2 phytase and its impact on digesta P and Ca concentrations in the gastrointestinal tract of pigs. In Exp. 1, 18 pigs (8.3 +/- 0.2 kg of BW) were allotted to 3 groups (n = 6 each) and fed a low-P (0.4%) corn-soybean meal, basal diet (BD), BD + phytase [500 units (U)/kg of feed], or BD + inorganic P (iP, 0.1%) for 4 wk. In Exp. 2, 30 pigs (14.5 +/- 0.2 kg of BW) were allotted to 3 groups (n = 10 each) and fed BD, BD + 500 U of phytase/kg of feed, or BD + 2,000 U of phytase/kg of feed for 2 wk. Five or six pigs from each treatment group were killed at the end of both experiments to assay for digesta phytase activity and soluble P concentration in 6 segments of the digestive tract and digesta total P and Ca concentrations in stomach and colon. Compared with pigs fed BD, pigs fed BD + 500 U of phytase/kg of feed in Exp. 1 and BD + 2,000 U of phytase/kg of feed in Exp. 2 had greater (P < 0.05) phytase activities in the digesta of the stomach and upper jejunum (2 m aborally from the duodenum). No phytase activity was detected in the digesta of the lower jejunum (2.12 m cranial to the ileocecal junction) or ileum from any of the treatment groups in either trial. Concentrations of digesta-soluble P peaked in the upper jejunum of pigs fed BD in Exp. 1 and 2, but showed gradual decreases between the stomach and the upper jejunum of pigs fed BD + phytase or BD + iP. In both experiments, pigs fed only BD had greater (P < 0.05) colonic digesta phytase activity and soluble P concentrations than those fed phytase. In Exp. 2, total colonic digesta P or Ca concentrations, or both, of pigs displayed a phytase-dose-dependent reduction (P < 0.05). In conclusion, supplemental dietary AppA2 mainly functioned in the stomach and was associated with a reduced phytase activity in colonic digesta of weanling pigs. 相似文献
12.
The effectiveness of an Escherichia coli phytase in comparison with a commercially available Aspergillus phytase in improving the bioavailability of phosphorus in broilers, layers and young pigs was studied in three separate experiments. Three basal diets, marginally deficient in dietary P mainly provided as phytate, were formulated. Both phytases were added to the diets at the rate of 500 U/kg diet. The phytases significantly (P < or = 0.05) improved the availability of phytate P to broilers, layers and young pigs. Aspergillus and E. coli phytases enhanced the pre-caecal digestibility of P by 11 and 29% for broilers and 18 and 25% for layers, respectively. Total tract digestibility of P (P balance) was also enhanced but with smaller magnitude. In pigs, total tract digestibility of P was improved by 33 and 34% by Aspergillus and E. coli phytases, respectively. Under the conditions of this study, it was observed that E. coli consistently, though with small magnitude in layers and pigs, enhanced the availability of phytate P at the same range or slightly better than Aspergillus phytase. It was only in pigs that the availability of Ca was significantly (P < or = 0.05) improved by addition of both phytases. It can be concluded that E. coli phytase is highly effective in improving the bioavailability of phytate P to broilers, layers and young pigs. This seems to be based on the high proteolytic stability of the enzyme in the digestive tract, as shown recently. 相似文献
13.
Tohru MATSUI 《Animal Science Journal》2002,73(1):21-28
A large amount of phosphorus (P) in corn and soybean meal is in the form of phytate that is poorly available to monogastric animals. It leads to the presence of large amounts of P in manure, which contributes to the P pollution problem. The fermentation of soybean meal with Aspergillus usamii almost completely degraded phytate and improved P availability in chicks. Although dietary yeast phytase increased P absorption and availability in pigs, its efficacy was less than that of Aspergillus niger phytase. It was suggested that the lesser efficacy of yeast phytase resulted from its lower stability against pepsin. Phytate suppresses zinc availability in monogastric animals. Zinc availability was improved by the substitution of regular soybean meal with fermented soybean meal and by the supplementation with Aspergillus niger phytase in pigs. It has been considered that phytate is easily degraded in the rumen and the availability of phytate P is high in ruminants. However, 20% of phytate in oilseed meals was not degraded in the rumen of sheep. Additionally, heating and formaldehyde treatments with oilseed meals suppressed ruminal degradation of phytate and approximately half of phytate escaped from ruminal degradation in the treated oilseed meals. 相似文献
14.
国标法测定植酸酶活性存在问题的探讨 总被引：5，自引：0，他引：5
利用国标法测定植酸酶活性过程中发现,植酸钠底物溶液pH为6.48,高于酶活性单位定义中pH5.5。为进一步探讨植酸钠底物溶液pH对植酸酶活性的影响,本试验研究了调节与不调节植酸钠底物溶液pH对样品空白的吸光值以及植酸酶活性的影响。结果表明:将植酸钠溶液pH由6.48调至5.5对酶活测定中的样品空白无显著影响(P>0.05),但极显著影响植酸酶活性(P<0.01),未调节pH组植酸酶活性仅相当于调节pH组的66%,利用不同的酸调节植酸钠溶液pH,对植酸酶活性无显著影响(P>0.05)。 相似文献
15.
Hill GM Link JE Rincker MJ Kirkpatrick DL Gibson ML Karges K 《Journal of animal science》2008,86(1):112-118
Two experiments were completed to determine the potential for using distillers dried grains with solubles (DDGS) in diets with or without phytase to provide available P, energy, and protein to highly productive lactating sows without increasing their fecal P. In Exp. 1, the dietary treatments were as follows: (1) corn and soybean meal with 5% beet pulp (BP) or (2) corn and soybean meal with 15% DDGS (DDGS). Besides containing similar amounts of fiber, diets were isonitrogenous (21% CP, 1.2% Lys) and isophosphorus (0.8% P). Sixty-one sows were allotted to dietary treatments at approximately 110 d of gestation (when they were placed in farrowing crates) based on genetics, parity, and date of farrowing. Sows were gradually transitioned to their lactation diet. On d 2 of lactation, litters were cross-fostered to achieve 11 pigs/litter. Sows and litters were weighed on d 2 and 18. Fecal grab samples were collected on d 7, 14, and 18 of lactation. Dietary treatment did not affect the number of pigs weaned (10.9 vs. 10.8) or litter weaning weight. On d 14, DDGS sows had less fecal P concentration than BP sows (28.3 vs. 32.8 mg/g; P = 0.04). Fecal Ca of sows fed DDGS decreased for d 7, 14, and 18 (55.6, 51.4, and 47.1 mg/g of DM, respectively; P = 0.05) but not for BP sows. In Exp. 2, the dietary treatments were as follows: (1) corn and soybean meal (CON), (2) CON + 500 phytase units of Natuphos/kg diet, as fed (CON + PHY), (3) corn and soybean meal with 15% DDGS and no phytase (DDGS), or (4) DDGS + 500 FTU of Natuphos/kg of diet, as fed (DDGS + PHY). Sows (n = 87) were managed as described for Exp 1. Litter BW gain (46.0, 46.3, 42.1, and 42.2 kg; P = 0.25) and sow BW loss (8.1, 7.2, 7.4, and 6.3 kg for CON, CON + PHY, DDGS, and DDGS + PHY, respectively; P = 0.97) were not affected by dietary treatment. Fecal P concentration did not differ among dietary treatments but was reduced at d 14 and 18 compared with d 7 (P = 0.001). However, fecal phytate P concentration was decreased by the addition of DDGS when DDGS and DDGS + PHY were compared with the CON sows except on d 7 (P < 0.05). Sows fed CON diet had greater fecal phytate P than sows fed DDGS, and sows fed DDGS + PHY had less fecal phytate P than sows fed DDGS with no phytase (P = 0.001). Although these experiments were only carried out for 1 lactation, these results indicate that highly productive sows can sustain lactation performance with reduced fecal phytate P when fed DDGS and phytase in lactation diets. 相似文献
16.
17.
The effect of coarsely ground meal feed versus finely ground heat-treated pelleted feed and the addition of lactic acid and formic acid in combination on the physico-chemical properties, microbial composition and concentration of organic acids in the stomach content of piglets was investigated. A total of 60 weaned piglets were included in a 2 × 2 factorial arrangement in 15 randomised complete blocks. After three weeks, the pigs were put down and samples of digesta from the gastrointestinal tract were analysed for dry matter (DM), pH, organic acids and microbiological enumeration. Feeding coarsely ground meal feed increased the DM percentage, the concentration of organic acids and pH in the proximal stomach and lowered the distal stomach pH compared with finely ground heat-treated pelleted feed. However, the addition of organic acids to the diets lowered the pH in the stomach and was able to reduce the population of enterobacteria in the stomach. 相似文献
18.
The efficacy of an Escherichia coli-derived phytase preparation 总被引：1，自引：0，他引：1
Five experiments were conducted to evaluate the effect of an Escherichia coli-derived phytase on phytate-P use and growth performance by young pigs. The first experiment involved time course, pH dependence, and phytase activity studies to investigate the in vitro release of P from corn, soybean meal, and an inorganic P-unsupplemented corn-soybean meal negative control diet. In Exp. 2, which was designed to determine the efficacy of the E. coli-derived vs. fungal phytase-added diets at 0, 250, 500, 750, 1,000, or 1,250 FTU/kg (as-fed basis; one phytase unit or FTU is defined as the quantity of enzyme required to liberate 1 micromol of inorganic P/min, at pH 5.5, from an excess of 15 microM sodium phytate at 37 approximately C) and a positive control diet, eight individually penned 10-kg pigs per diet (12 diets, 96 pigs) were used in a 28-d growth study. The third experiment was a 10-d nutrient balance study involving six 13-kg pigs per diet (four diets, 24 pigs) in individual metabolism crates. In Exp. 4, eight pens (four pigs per pen) of 19-kg pigs per treatment were used in a 42-d growth performance study to examine the effect of adding the E. coli-derived phytase to corn-soybean diets at 0, 500, or 1,000 FTU/kg (as-fed basis) and a positive control (four diets, 128 pigs). In Exp. 5, six 19-kg pigs per treatment were used in a 10-d nutrient balance study to investigate the effects of the E. coli-derived phytase added to diets at 0, 250, 500, 750, or 1,000 FTU/kg (as-fed basis) and a positive control diet (six diets, 36 pigs). The in vitro study showed that the E. coli-derived phytase has an optimal activity and pH range of 2 to 4.5. Inorganic phosphate release was greatest for soybean meal, least for corn, and intermediate for the negative control diet. Dietary supplementation with graded amounts of E. coli-derived phytase resulted in linear increases (P < 0.05) in weight gain, feed efficiency, and plasma Ca and P concentrations in 10-kg pigs in Exp. 2. Phytase also increased P digestibility and retention in the 13-kg pigs in Exp. 3. In Exp. 4, dietary supplementation with E. coli-derived phytase resulted in linear increases (P < 0.05) in weight gain and feed efficiency of 19-kg pigs. Supplementation of the diets of 19-kg pigs with the E. coli-derived phytase also improved Ca and P digestibility and retention in Exp. 5. In the current study, the new E. coli-derived phytase was efficacious in hydrolyzing phytate-P, both in vitro and in vivo, in young pigs. 相似文献
19.
E. Humer C. Schwarz K. Schedle 《Journal of animal physiology and animal nutrition》2015,99(4):605-625
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. 相似文献
20.
Gyo-Moon CHU Hideyuki OHMORI Tomoyuki KAWASHIMA Masayuki FUNABA Tohru MATSUI 《Animal Science Journal》2009,80(4):433-437
Microbes such as yeast and Aspergillus are known to produce phytase, and Aspergillus phytase has been used as a feed additive for improving phytate-phosphorus bioavailability in monogastric animals. We measured phytase activity in some by-products from fermented food and beverage productions by yeast and Aspergillus . The phytase activity was as high as 3577 and 2225 PU/kg DM in raw and dried brewer's yeasts, respectively. On the other hand, the phytase activity was approximately 400 PU/kg DM in white-wine yeast and red-wine yeast. The phytase activity was further low in natto (fermented soybean) residue, soy sauce cake, rice brewer's grain and the activity was not detected in dried corn-barley distiller's grain with soluble and sweet-potato distiller's residue. The stability of phytase against pepsin was much lower in the brewer's yeast than in an Aspergillus phytase preparation. On the other hand, the addition of raw brewer's yeast effectively degraded phytate phosphorus in a corn-soybean meal diet during soaking. These results suggest that phytase in the examined by-products is not suitable for the phytase source of conventional diets, but that the soaking treatment with a raw brewer's yeast is an alternative method for improving phytate-phosphorus bioavailability in corn-soybean meal diets for pigs. 相似文献