Effects of temperature, pH, incubation time and pepsin concentration on the in vitro stability of intrinsic phytase of wheat, barley and rye

Effect of crop retention time and acidification of the feed on phytase efficacy in broiler chickens

1. An in vitro test to study the effect of pH reduction on phytic acid degradation over time for four commercial phytases was conducted. Changing the pH level affected phytate degradation over time differently for the various phytases (P < 0.05).2. The phytase with the largest response of pH reduction in the in vitro test and a feed pH level of 4.5 was chosen for the broiler experiment. The effect of intermittent feeding, addition of 500 FYT C. braakii-derived phytase and 1% formic acid were tested in a 2 x 2 x 2 factorial arrangement. Ten pens containing 10 birds each were fed each of the treatment combinations from 15 to 36 d of age. Ad libitum fed birds had two 4-h dark periods with 2-h light in-between, while intermittently fed birds in addition had restricted access to the feed through except for four 1-h and one 2-h feeding bouts.3. In addition to assessing performance, excreta were collected on a pen basis. The tibia and contents from jejunum and ileum were collected from one bird per pen. In addition, crop contents were collected from the intermittently fed birds 80, 160 and 240 min after the start of feeding.4. Phytase improved performance, ileal and jejunal P digestibility, P retention and tibia ash and P concentration (P < 0.001). Intermittent feeding increased jejunal P digestibility and P retention (P < 0.001), but ileal P digestibility increased only in the intermittently fed birds compared to the ad libitum fed birds without phytase addition (P = 0.025). Acidification increased jejunal P digestibility only in the ad libitum fed birds (P = 0.019). There was a considerable inositol hexakisphosphate degradation into lower isomers in the crop after 80 min for diets with phytase (InsP_{3 and 4}:P < 0.001), and acidification further increased this degradation (InsP₄:P = 0.007). After 160 min retention time, the effect of phytase and acidification was even higher with more significant (P < 0.05) interactions.5. The current data showed that prolonged retention time in the crop combined with feed acidification increased phytase efficacy by improving the phytate degradation.

Improvement in the in vitro Digestibility of Shrimp Meal by the Addition of Persimmon Peel

The present study was conducted to analyze the chemical properties of persimmon peel (PP) and the in vitro digestibility of shrimp meal (SM) diets containing PP. Discussions whether PP can be used as a feed additive to promote digestion of SM in chickens are also included. The chemical composition and chitinase activity of dried PP was studied. SM diets containing PP were formulated according to the 4 by 6 factorial design: 4 levels of SM (0%, 10%, 15%, and 20%) × 6 levels of PP (0%, 2%, 4%, 6%, 8%, and 10%). The in vitro digestibility of dry matter (IVDMD), crude protein (IVCPD), and chitin (IVCD) was also studied. PP was rich in nitrogen-free extract (NFE, about 74%) and tannin (2.8%), and the highest chitinase activity of PP was observed at pH 4.5. Approximately 50% of chitinase activity was also observed at acidic (3.0) and alkaline (8.0) pH. Its activity was slightly affected by pepsin treatment. IVDMD increased upon addition of up to 8% PP, but decreased with an increase in the level of SM. When PP level was increased up to 6%, IVCPD in the group containing 0% SM, changed slightly; however, an increasing trend was observed in the other groups. When PP level was more than 6%, IVCPD decreased in all the groups. IVCD increased dose-dependently with increasing level of PP and decreased with increasing level of SM. In conclusion, PP was rich in NFE, had high chitinase activity, and improved all digestibility parameters, such as IVDMD, IVCPD, and IVCD, in SM diets where the PP level was under 6%. Thus, up to 6% of PP can be safely included in SM diets as a digestion promoter.

Effect of a high dose of exogenous phytase and supplementary myo-inositol on mineral solubility of broiler digesta and diets subjected to in vitro digestion assay

This study was conducted to evaluate the effect of microbial phytase and myo-inositol supplementation in low non-phytate phosphorus (nPP) diets on pH and the solubility of minerals in an in vitro digestion procedure (IVDP) and to compare this with digesta from birds fed different diets (grower diets) compared to the in vitro test (starter diets). A total of 660 1-day-old broilers were randomly allotted into 11 dietary treatments and fed a corn-soybean-meal-based diet with recommended nPP (positive control; PC), an nPP-deficient diet (negative control; NC), NC diets supplemented with phytase (500; 1,000; 2,000; 3,000; 4,000; 5,000; and 6,000 FTU/kg), an NC diet plus 0.15% myo-inositol, and an NC diet with reduced Ca level (Ca: nPP ratio same as PC) from 1 to 23 D of age. The pH and Ca solubility of the NC diet was increased compared with the PC when subjected to IVDP (P < 0.05). P solubility in the gizzard and jejunal digesta was reduced in the NC compared with the PC diet and this was also reflected in the IVDP. Phytase addition to the NC diets linearly increased (P < 0.05) the pH value and Ca and P solubilities in both digesta and diets subjected to IVDP. Higher doses of microbial phytase increased (P < 0.05) Zn and Fe solubilities in both digesta and IVDP. Myo-inositol supplementation of the NC diet had no effect on mineral solubility, but decreased (P < 0.05) the pH of the IVDP. Lowering the Ca content of the NC diet decreased (P < 0.05) the pH of the in vitro digested diets and Ca solubility in both broiler digesta and IVDP and also increased (P < 0.05) P solubility in both the jejunal digesta and IVDP. Correlations were noted between the solubility of P in the in vitro assay and that in the gizzard and jejunal digesta, and also with bird performance, confirms the usefulness of in vitro assay.

Enhanced mannan-derived fermentable sugars of palm kernel cake by mannanase-catalyzed hydrolysis for production of biobutanol

Catalytic depolymerization of mannan composition of palm kernel cake (PKC) by mannanase was optimized to enhance the release of mannan-derived monomeric sugars for further application in acetone-butanol-ethanol (ABE) fermentation. Efficiency of enzymatic hydrolysis of PKC was studied by evaluating effects of PKC concentration, mannanase loading, hydrolysis pH value, reaction temperature and hydrolysis time on production of fermentable sugars using one-way analysis of variance (ANOVA). The ANOVA results revealed that all factors studied had highly significant effects on total sugar liberated (P<0.01). The optimum conditions for PKC hydrolysis were 20% (w/v) PKC concentration, 5% (w/w) mannanase loading, hydrolysis pH 4.5, 45°C temperature and 72h hydrolysis time. Enzymatic experiments in optimum conditions revealed total fermentable sugars of 71.54±2.54g/L were produced including 67.47±2.51g/L mannose and 2.94±0.03g/L glucose. ABE fermentation of sugar hydrolysate by Clostridium saccharoperbutylacetonicum N1-4 resulted in 3.27±1.003g/L biobutanol.

Phytase-mediated mineral solubilization from cereals under in vitro gastric conditions

BACKGROUND

Enzymatic dephosphorylation of phytic acid (inositol hexakisphosphate) in cereals may improve mineral bioavailability in humans. This study quantified enzymatic dephosphorylation of phytic acid by measuring inositol tri- to hexakisphosphate (InsP3-6) degradation and iron and zinc release during microbial phytase action on wheat bran, rice bran and sorghum under simulated gastric conditions.

RESULTS

InsP3-6 was depleted within 15-30 min of incubation using an Aspergillus niger phytase or Escherichia coli phytase under simulated gastric conditions, with the two enzymes dephosphorylating cereal phytic acid at similar rates and to similar extents. Microbial phytase-catalyzed phytate dephosphorylation was accompanied by increased iron and zinc release from the cereal substrates. However, for wheat bran at pH 5, the endogenous wheat phytase activity produced mineral release equal to or better than that of the microbial phytases. No increases in soluble cadmium, lead or arsenic were observed with microbial phytase-catalyzed phytate dephosphorylation.

CONCLUSION

Microbial phytase treatment abated phytate chelation hence enhanced the release of iron and zinc from phytate-rich cereals under simulated gastric conditions. The data infer that acid-stable microbial phytases can help improve iron bioavailability from phytate-rich cereal substrates via post-ingestion activity. © 2015 Society of Chemical Industry.

Phosphorus management in Europe in a changing world

Food production in Europe is dependent on imported phosphorus (P) fertilizers, but P use is inefficient and losses to the environment high. Here, we discuss possible solutions by changes in P management. We argue that not only the use of P fertilizers and P additives in feed could be reduced by fine-tuning fertilization and feeding to actual nutrient requirements, but also P from waste has to be completely recovered and recycled in order to close the P balance of Europe regionally and become less dependent on the availability of P-rock reserves. Finally, climate-smart P management measures are needed, to reduce the expected deterioration of surface water quality resulting from climate-change-induced P loss.

Activation of Endogenous Phytase and Degradation of Phytate in Wheat Bran

Wheat bran contains a significant amount of the anti-nutritional factor phytate. This study is the first to explore the effectiveness of activating endogenous phytase and further reducing phytate content through resulting programmed cell death (PCD). Effects of solid-liquid ratio (1:1, 1:2, 1:3, and 1:6), incubation temperature (4, 20, 38, 55, and 70 °C), metal ions (Na⁺, K⁺, Ca²⁺, and Mg²⁺), gibberellin concentration (0, 5, 50, 500, 2000, and 5000 mg/L), hydrogen peroxide concentration (0, 0.2, 0.4, 0.6, 0.8, and 1.0%), and incubation time (30, 80, 180, and 360 min) on activation of endogenous phytase activity and phytate degradation in wheat bran samples are discussed in this study. It was found that when the wheat bran was incubated with distilled water at 55 °C for 80 min, its endogenous phytase activity was dramatically increased 4-fold from 12.96 to 53.54 FTU/g, whereas the phytate content was reduced by about 70% from 45.20 to 13.52 mg/g. By comparison of photomicrographs of raw wheat bran sample and sample incubated with distilled water for 360 min at 55 °C, a conclusion could be drawn that PCD in aleurone cells had occurred.

Lactic acid and thermal treatments trigger the hydrolysis of myo-inositol hexakisphosphate and modify the abundance of lower myo-inositol phosphates in barley (Hordeum vulgare L.)

Barley is an important source of dietary minerals, but it also contains myo-inositol hexakisphosphate (InsP₆) that lowers their absorption. This study evaluated the effects of increasing concentrations (0.5, 1, and 5%, vol/vol) of lactic acid (LA), without or with an additional thermal treatment at 55°C (LA-H), on InsP₆ hydrolysis, formation of lower phosphorylated myo-inositol phosphates, and changes in chemical composition of barley grain. Increasing LA concentrations and thermal treatment linearly reduced (P<0.001) InsP₆-phosphate (InsP₆-P) by 0.5 to 1 g compared to the native barley. In particular, treating barley with 5% LA-H was the most efficient treatment to reduce the concentrations of InsP₆-P, and stimulate the formation of lower phosphorylated myo-inositol phosphates such as myo-inositol tetraphosphate (InsP₄) and myo-inositol pentaphosphates (InsP₅). Also, LA and thermal treatment changed the abundance of InsP₄ and InsP₅ isomers with Ins(1,2,5,6)P₄ and Ins(1,2,3,4,5)P₅ as the dominating isomers with 5% LA, 1% LA-H and 5% LA-H treatment of barley, resembling to profiles found when microbial 6-phytase is applied. Treating barley with LA at room temperature (22°C) increased the concentration of resistant starch and dietary fiber but lowered those of total starch and crude ash. Interestingly, total phosphorus (P) was only reduced (P<0.05) in barley treated with LA-H but not after processing of barley with LA at room temperature. In conclusion, LA and LA-H treatment may be effective processing techniques to reduce InsP₆ in cereals used in animal feeding with the highest degradation of InsP₆ at 5% LA-H. Further in vivo studies are warranted to determine the actual intestinal P availability and to assess the impact of changes in nutrient composition of LA treated barley on animal performance.

Mitigation options to reduce phosphorus losses from the agricultural sector and improve surface water quality: a review

The EU Water Framework Directive (WFD) obliges Member States to improve the quality of surface water and groundwater. The measures implemented to date have reduced the contribution of point sources of pollution, and hence diffuse pollution from agriculture has become more important. In many catchments the water quality remains poor. COST Action 869 was an EU initiative to improve surface water quality that ran from 2006 to 2011, in which 30 countries participated. Its main aim was a scientific evaluation of the suitability and cost-effectiveness of options for reducing nutrient loss from rural areas to surface waters at catchment scale, including the feasibility of the options under different climatic and geographical conditions. This paper gives an overview of various categories of mitigation options in relation to phosphorus (P). The individual measures are described in terms of their mode of action, applicability, effectiveness, time frame, environmental side-effects (N cycling) and cost. In total, 83 measures were evaluated in COST Action 869.