In vitro evaluation of probiotic potential and enzymatic profiling of Pichia kudriavzevii Y33 isolated from traditional home-made mango pickle

Background

Fermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily lactic acid bacteria, yeasts, and filamentous molds, for the manufacture of edible foods. Yeast isolated from home-made mango pickle from Hamirpur, Himachal Pradesh, was assessed for probiotic properties and their enzymatic profiling.

Results

Four yeast isolates were isolated out of which P. kudriavzevii Y33 was selected on the basis of high acid tolerance as well as broadest antimicrobial activity. The selected isolate was observed to have high acid tolerance at pH 2 and show strong antimicrobial activity against all the pathogens examined. P. kudriavzevii Y33 can also withstand high bile concentration and showed high viability index, i.e., 95% at concentration of 2% of bile. The isolate was able to demonstrate high cholesterol assimilation in medium containing ox bile and taurocholate, at 88.58 and 86.83%, respectively. The autoaggregation ability of isolate increases with increasing the time of incubation and showed 87% of autoaggregation after 24 h of incubation. P. kudriavzevii Y33 exhibited resistance towards different antibiotics, found to be positive for exopolysaccharide production and showed no hemolytic activity. The isolate was observed to produce several enzymes such as β-galactosidase, protease, amylase, phytase, and lipase.

Conclusions

The results of the current study revealed that P. kudriavzevii Y33 has various beneficial qualities that suggest it could be used as probiotics. Enzymes produced by yeast isolate help in improving flavor and mineral availability in the fermented products.

Microbial engineering for the production and application of phytases to the treatment of the toxic pollutants: A review

Phytases are a group of digestive enzymes which are commonly used as feed enzymes. These enzymes are used exogenously in the feeds of monogastric animals thereby it improves the digestibility of phosphorous and thus reduces the negative impact of inorganic P excretion on the environment. Even though these enzymes are widely distributed in many life forms, microorganisms are the most preferred and potential source of phytase. Despite the extensive availability of the phytase-producing microbial consortia, only a few microorganisms have been known to be exploited at industrial level. The high costs of the enzyme along with the incapability to survive high temperatures followed by the poor storage stability are noted to be the bottleneck in the commercialization of enzymes. For this reason, besides the conventional fermentation approaches, the applicability of cloning, expression studies and genetic engineering has been implemented for the past few years to accomplish the abovesaid benefits. The site-directed mutagenesis as well as knocking out have also validated their prominent role in microbe-based phytase production with enhanced levels. The present review provides detailed information on recent insights on the modification of phytases through heterologous expression and protein engineering to make thermostable and protease-resistant phytases.

Effects of phytase supplementation of high-plant-protein diets on growth, phosphorus utilization, antioxidant, and digestion in red swamp crayfish (Procambarus clarkii)

Fish meal is increasingly being replaced by plant protein raw materials, meanwhile, it brings phytic acid, which combines with phosphorus to form phytate phosphorus and leads to a low utilization rate of phosphorus in shrimp. To solve this problem, this study investigated the effects of phytase supplementation on growth performance, phosphorus utilization, antioxidants, and digestion in red swamp crayfish (Procambarus clarkii). Crayfish (initial mean weight: 8.69 ± 0.15 g, N = 324) were randomly divided into six groups each with three replicates of 18 individuals each, and hand-fed for 8 weeks with one of six experimental diets (50 and 490 g kg^-1 animal and plant protein raw material, respectively): negative control (NC; 11.0 g kg^-1 phosphorus), positive control (PC; 15 g kg^-1 NaH₂PO₄ added to NC; 14.7 g kg^-1 phosphorus), and phytase supplementation diets (P1-P4: 0.1, 0.2, 0.4, and 0.6 g kg^-1 phytase added to NC, respectively). The feeding trial was performed in a micro-flow water culture system. P2 showed a significantly higher weight gain rate (WGR), specific growth rate, protein efficiency ratio, and protein retention efficiency (PRE) but showed the lowest feed conversion ratio (FCR) than other groups. Broken-line regression analyses using WGR, FCR, and PRE as evaluation indices showed that the optimal dietary phytase supplementation level was 0.233, 0.244, and 0.303 g kg^-1, respectively. P2 showed the highest crude protein content of whole crayfish and abdominal muscle, and phosphorus deposition rate, which was significantly higher than that in NC and PC. P3 showed the highest calcium and phosphorus contents in whole crayfish and phosphorus content in abdominal muscle, and calcium and inorganic phosphorus content in serum, which were significantly higher than those in NC. P3 showed significantly lowest serum alkaline phosphatase, alanine aminotransferase, aspartate transaminase activities, malondialdehyde content in hepatopancreas, and highest catalase activity, which were significantly lower and higher, respectively, than those in NC and PC. In summary, the addition of 0.2-0.4 g kg^-1 phytase significantly improves the growth performance, feed utilization, digestive enzyme activity, and antioxidant of P. clarkii, which has a similar effect to the direct addition of NaH₂PO₄ at 15 g kg^-1 to the feed.

Impact of phosphorous-deficit conditions on morpho-physiological traits and phosphorous metabolism in chickpea genotypes

Chickpea, an important food legume, is primarily grown on marginal soils with low soil fertility. Although chickpea can fix N, soil phosphorus (P) deficiency in crop growing areas is a major limiting factor for chickpea production. This study was undertaken to evaluate twenty-five chickpea cultivars for morpho-physiological traits and yield under low and normal phosphorous conditions. Based on morpho-physiological traits such as length and area of roots and shoots, root length density, root and shoot biomass, chlorophyll content, number of nodules and root tips, tolerance indices and yield, these cultivars were characterised into susceptible (ICC67, ICC1915, ICC2593, ICC5337, ICC5879, ICC8950, ICC13441, ICC1483, ICC15606 and ICC15888), tolerant (ICC10755, IG72070, ICCV97105, ICCV2, ICCV92809, ICCV92337 and ICCV95423) and the remaining cultivars were moderately tolerant to phosphorous-deficit conditions. Higher activities of enzymes of phosphorous metabolism such as acid phosphatase and phytase in roots and nodules of tolerant chickpea cultivars (ICCV97105, ICCV92337, ICCV95423) as compared to susceptible cultivars (ICC67, ICC15606, ICC15888) at different developmental stages might be attributing to their better performance for growth parameters and productivity traits under phosphorous-deficit conditions.

The impact of dietary calcium content on phosphorus absorption and retention in growing pigs is enhanced by dietary microbial phytase supplementation

Sixty growing male pigs were used to test the hypothesis that high dietary Ca content reduces P absorption to a greater extent in microbial phytase-supplemented diets via reducing inositol phosphate (IP) degradation and enhancing P precipitation. Pigs were equally allotted over diets with three Ca contents 2·0, 5·8 and 9·6 g/kg with or without microbial phytase (0 v. 500 FTU/kg) in a 2 × 3 factorial arrangement. Faeces and urine were collected at the end of the 21-d experimental period. Subsequently, pigs were euthanised and digesta quantitatively collected from different gastrointestinal tract (GIT) segments. Increasing dietary Ca content reduced apparent P digestibility in all GIT segments posterior to the stomach (P < 0·001), with greater effect in phytase-supplemented diets in the distal small intestine (Pinteraction = 0·007) and total tract (Pinteraction = 0·023). Nonetheless, increasing dietary Ca to 5·8 g/kg enhanced P retention, but only in phytase-supplemented diets. Ileal IP6 degradation increased with phytase (P < 0·001) but decreased with increasing dietary Ca content (P = 0·014). Proportion of IP esters in total IP (∑IP) indicated that IP6/∑IP was increased while IP4/∑IP and IP3/∑IP were reduced with increasing dietary Ca content and also with a greater impact in phytase-supplemented diets (Pinteraction = 0·025, 0·018 and 0·009, respectively). In all GIT segments, P solubility was increased with phytase (P < 0·001) and tended to be reduced with dietary Ca content (P < 0·096). Measurements in GIT segments showed that increasing dietary Ca content reduced apparent P digestibility via reducing IP degradation and enhancing P precipitation, with a greater impact in phytase-supplemented diets due to reduced IP degradation.

Immobilized phytases: an overview of different strategies, support material, and their applications in improving food and feed nutrition

Phytases are the most widely used food and feed enzymes, which aid in nutritional improvement by reducing anti-nutritional factor. Despite the benefits, enzymes usage in the industry is restricted by several factors such as their short life-span and poor reusability, which result in high costs for large-scale utilization at commercial scale. Furthermore, under pelleting conditions such as high temperatures, pH, and other factors, the enzyme becomes inactive due to lesser stability. Immobilization of phytases has been suggested as a way to overcome these limitations with improved performance. Matrices used to immobilize phytases include inorganic (Hydroxypatite, zeolite, and silica), organic (Polyacrylamide, epoxy resins, alginate, chitosan, and starch agar), soluble matrix (Polyvinyl alcohol), and nanomaterials including nanoparticles, nanofibers, nanotubes. Several surface analysis methods, including thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and FTIR analysis, have been used to characterize immobilized phytase. Immobilized phytases have been used in a broad range of biotechnological applications such as animal feed, biodegradation of food phytates, preparations of myo-inositol phosphates, and sulfoxidation by vanadate-substituted peroxidase. This article provides information on different matrices used for phytase immobilization from the last two decades, including the process of immobilization and support material, surface analysis techniques, and multifarious biotechnological applications of the immobilized phytases.

Interactive Effects of Copper Sources and a High Level of Phytase in Phosphorus-Deficient Diets on Growth Performance, Nutrient Digestibility, Tissue Mineral Concentrations, and Plasma Parameters in Nursery Pigs

The present study investigated the interactive effects of copper sources and a high level of phytase on growth performance, nutrient digestibility, tissue mineral concentrations, and plasma parameters in nursery pigs. Weaning piglets (N = 192; 6.06 ± 0.99 kg), blocked by body weight, were randomly allotted to 1 of 4 dietary treatments, with 12 pens per treatment and 4 pigs per pen. A basal diet for each phase was formulated to meet nutrient requirements for nursery pigs with the exception that standardized total tract digestibility (STTD) P was reduced by 0.12% and Ca was adjusted to achieve Ca/STTD P = 2.15. The 4 dietary treatments were arranged in a 2 × 2 factorial design, with 2 Cu sources (125 mg/kg Cu from copper methionine hydroxy analogue chelate (Cu-MHAC) or copper sulfate (CuSO₄)) and 2 phytase levels (0 or 1500 phytase units (FTU)/kg). Results showed that there was an interaction (P < 0.05) between Cu sources and phytase on ADG during days 0-41. When phytase was not present in the diets (P deficient), there was no difference between the two Cu sources in terms of ADG during days 0-41, whereas with phytase in the diets, Cu-MHAC tended to improve (P < 0.10) ADG during days 0-41 compared with CuSO₄. Pigs fed Cu-MHAC had greater apparent total tract digestibility (ATTD) of neutral and acid detergent fiber and STTD of P than those fed CuSO₄. Phytase increased (P < 0.05) growth performance, ATTD of Ca and P, and plasma inositol and growth hormone concentrations. In conclusion, Cu-MHAC may be more effective in improving growth rate than CuSO₄ when phytase was supplemented at 1500 FTU/kg. Cu-MHAC enhanced fiber and P digestibility regardless of phytase, compared with CuSO₄. Phytase addition in P-deficient diets was effective in improving growth performance, Ca and P digestibility, and plasma inositol and growth hormone concentrations.

Phytase blends for enhanced phosphorous mobilization of deoiled seeds

Phytases are hydrolytic enzymes capable of a stepwise phosphate release from phytate which is the main phosphorous storage in seeds, cereals and legumes. Limitations such as low enzyme activity or incomplete phytate hydrolysis to inositol are a great challenge in phytase applications in food and feed. Herein we report a phytase blend of two enzymes with additive effects on phytate (InsP6) hydrolysis and its application in the enzymatic phosphorous recovery process. Blending the fast 6-phytase rPhyXT52 with the 3-phytase from Debaryomyces castellii, which is capable of fully hydrolyzing InsP6, we achieved rapid phosphate release with higher yields compared to the individual enzymes and a rapid disappearance of InsP6-3 intermediates, monitored by HPLC. NMR data suggest a nearly complete phytate hydrolysis to inositol and phosphate. The blend was applied for phosphate mobilization from phytate-rich biomass, such as deoiled seeds. For this emerging application, an up to 43% increased phosphate mobilization yield was achieved when using 1000 U of the blend per kg biomass compared to using only the E. coli phytase. Even so, the time of enzyme treatment was decreased by more than half (6 h instead of 16 h) when using 4000 U of blend, we reached a 78-90% reduction of the total phosphorous content in the explored deoiled seeds. In summary, the phytase blend of Dc phyt/rPhyXT52 was proven very efficient to obtain inositol phosphate depleted meal which has its potential application in animal feeding and is concomitant with the production of green phosphate from renewable resources.

Growth performance, internal organ traits, intestinal morphology, and microbial population of broiler chickens fed quinoa seed-based diets with phytase or protease supplements and their combination

The aim of this study was to evaluate the effects of quinoa seed-based diets with phytase and protease enzymes, individually or in combination, on the productive performance, internal organs, microbiota activity, and intestinal morphology of broiler chickens. A total of 250 1-day-old broiler chicks (ROSS 308) were randomly distributed into five treatments with each five replicate pens of 10 birds in a 42-day trial. Dietary treatments were a conventional diet (CC) based on a corn-soybean meal or an experimental diet (EC) which contained 150 g/kg of quinoa seed. Other treatments were EC diet supplemented with 500 FTU/kg phytase (EPH), 0.2 g/kg protease (EPR) enzymes, or their combination (EPPC). At the end of the trial, the feed intake of the EPH broilers was higher than those of the EC and EPPC birds (P < 0.05). Meanwhile, broiler chickens fed the EPH and EPPC diets had higher body weight gain compared with those of the birds fed the other diets (P < 0.05). The EC and EPPC broilers consumed less feed than the EPH birds (P < 0.05), while CC and EPR birds were intermediate. The EC group had the highest feed conversion ratio among all groups (P < 0.05). The EPPC group had the best feed conversion ratio compared with other groups except for the EPH group (P < 0.05). The highest relative weight of the bursa and spleen was observed in EPPC and CC groups, respectively. The pancreas had the lowest weight in the broilers fed protease-supplemented diet. An increase in villus length and villus width was observed in birds fed EPH and EC diets, respectively (P < 0.05). The ratio of VL to crypt depth was greater in the phytase-supplemented group (P < 0.05). Inclusion of phytase or phytase + protease to QS diet increased the cecal Lactobacillus population, while the count of Coliforms decreased in EPR and EPPC groups (P < 0.05). It is concluded that addition of phytase and protease enzymes to QS-based diet may have beneficial effects on the growth performance, gut bacteria ecology, and intestinal morphology of broiler chickens.

A systematic-review on the role of exogenous enzymes on the productive performance at weaning, growing and finishing in pigs

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Supplementation of exogenous enzymes in the general diet improves production characteristics in all stages of production.

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Phytases are the most supplemented enzymes in all productive stages of pigs.

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The inclusion of Phytases, used in the pig's diet showed an average dry matter digestibility (g/kg) 840.6 ± 25.5 in weaning, 862.5 ± 7.4 in growing and 802.0 ± 1.41 in finishing.

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The inclusion of xylanases used in the pig's diet showed an average in dry matter digestibility (g/kg) 829.5 ± 7.14 in weaning and 759.1 ± 6.93 in finishing stages.

Supplementing exogenous enzymes in pig diets is an alternative solution to increase dietary energy and fiber digestibility to improve pig production performance at a low production cost and to reduce environmental impact with lower N and P excretions. The production stage, diet composition, enzyme source, amount and number of enzymes added, are factors to consider before using them. A database composed by 227 individual diets, resulting from 43 studies with 48 experimental records were divided in different production stages, with 19 records for weaning, 17 records for growing and 12 records for finishing. A descriptive statistical analysis of the chemical composition of the diets and enzyme doses was carried out. The data with normal distribution were analyzed calculating the mean, the minimum and maximum length, the standard deviation and the coefficient of variation. It was found that combined enzymes are the most widely reported enzyme combination in the supplementation of pigs at all stages of production. Phytases and Mannanases are commonly used at weaning and growing stages. Xylanases and Proteases have been reported to be used in all production stages. However, the highest yielding enzymes at weaning, growing and finishing stages were Phytases and Mannanases. Dietary supplementation of exogenous enzymes improves production characteristics at all stages of production. However, an improvement in growth performance and nutrient digestibility is not always observed. Future studies should focus on the interaction between production stages, composition of the diet, origin of the enzyme and the amount and number of enzymes added.

Prediction of calcium and phosphorus requirements for pigs in different bodyweight ranges using a meta-analysis

Several studies have focused on Ca and P requirements for pigs. These requirements are estimated from their retention and bone formation. However, modern pig breeds have different responses to dietary Ca and P than traditional breeds, and their requirements are expected to change on an annual basis. Besides individual Ca and P needs, the Ca to P ratio (Ca/P) is an important factor in determining requirements. This study aimed to implement a linear and quadratic regression analysis to estimate Ca and P requirements based on average daily gain (ADG), apparent total tract digestibility (ATTD) of Ca (ATTD-Ca), ATTD of P (ATTD-P), and crude protein (CP) digestibility. Results show that Ca/P had linear and quadratic effects on ADG in the phytase-supplemented (PS) group in both the 6–11 kg and 11–25 kg categories. In the latter category, the CP digestibility was linearly increased in response to increasing Ca/P in the without-phytase (WP) group. In the 25–50 kg category, there was a linear response of ADG and linear and quadratic responses of CP digestibility to Ca/P in the PS group, while a linear and quadratic increase in CP digestibility and a quadratic effect on ATTD-Ca were observed in the WP group. In the 50–75 kg category, Ca/P had significant quadratic effects on ADG in the PS and WP groups, along with significant linear and quadratic effects on ATTD-Ca. In addition, Ca/P had significant quadratic effects on ATTD-P and led to a significant linear and quadratic increase in the CP digestibility in the WP group. In the 75–100 kg category, analysis showed a significant decrease in ATTD-Ca and ATTD-P in the PS and WP groups; in the latter, ATTD-P and ATTD-Ca were linearly decreased by increasing Ca/P. In conclusion, our equations predicted a higher Ca/P in the 6–25 kg bodyweight categories and a lower Ca/P in the 50-100 kg category than that recommended in the literature.

Engineering of thermostable phytase-xylanase for hydrolysis of complex biopolymers

Industrial processing of enzymes requires higher heating that affects the thermal stability of the enzyme and increases the production cost. In this study, xylanase-phytase (XP) fusion protein was generated via co-expression in a single vector with a cold-shock promoter, leading to improved activity at optimal pH, temperature and the thermal behaviour of the protein. Xylanase-phytase (XP) fusion and phytase proteins were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The XP fusion was thermally stable up to 124 °C, higher than phytase which was steady up to 113.5 °C. XP fusion exhibits higher stability at its thermal transition midpoint (T _m) 108 °C, higher than the T _m value of phytase which is 90 °C. Industrially efficient and environment-friendly proteins with low production cost and higher stability can be generated by 'fusion protein' technology.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02936-z.

Generation of phytase chimeras with low sequence identities and improved thermal stability

Being able to recombine more than two genes with four or more crossover points in a sequence independent manner is still a challenge in protein engineering and limits our capabilities in tailoring enzymes for industrial applications. By computational analysis employing multiple sequence alignments and homology modeling, five fragments of six phytase genes (sequence identities 31-64 %) were identified and efficiently recombined through phosphorothioate-based cloning using the PTRec method. By combinatorial recombination, functional phytase chimeras containing fragments of up to four phytases were obtained. Two variants (PTRec 74 and PTRec 77) with up to 32 % improved residual activity (90 °C, 60 min) and retained specific activities of > 1100 U/mg were identified. Both variants are composed of fragments from the phytases of Citrobacter braakii, Hafnia alvei and Yersinia mollaretii. They exhibit sequence identities of ≤ 80 % to their parental enzymes, highlighting the great potential of DNA recombination strategies to generate new enzymes with low sequences identities that offer opportunities for property right claims.

Phytic acid accumulation in plants: Biosynthesis pathway regulation and role in human diet

Phytate or phytic acid (PA), is a phosphorus (P) containing compound generated by the stepwise phosphorylation of myo-inositol. It forms complexes with some nutrient cations, such as Ca, Fe and Zn, compromising their absorption and thus acting as an anti-nutrient in the digestive tract of humans and monogastric animals. Conversely, PAs are an important form of P storage in seeds, making up to 90% of total seed P. Phytates also play a role in germination and are related to the synthesis of abscisic acid and gibberellins, the hormones involved in seed germination. Decreasing PA content in plants is desirable for human dietary. Therefore, low phytic acid (lpa) mutants might present some negative pleiotropic effects, which could impair germination and seed viability. In the present study, we review current knowledge of the genes encoding enzymes that function in different stages of PA synthesis, from the first phosphorylation of myo-inositol to PA transport into seed reserve tissues, and the application of this knowledge to reduce PA concentrations in edible crops to enhance human diet. Finally, phylogenetic data for PA concentrations in different plant families and distributed across several countries under different environmental conditions are compiled. The results of the present study help explain the importance of PA accumulation in different plant families and the distribution of PA accumulation in different foods.

Safety and efficacy profile of a phytase produced by fermentation and used as a feed additive

Enzymes can aid in optimal feed stock utilization when used as feed additives. A range of toxicological studies were performed to evaluate the safety profile of a novel phytase (phytase HM) from Citrobacterbraakii produced in Aspergillus oryzae. Phytase HM was found to be non-mutagenic and non-clastogenic in in vitro tests. Further, the phytase HM preparation did not exhibit irritative potential to the eye and skin when applied in in vitro models. A 13-week subchronic toxicity study with oral administration of phytase HM to rats did not show any adverse effects. Efficacy studies showed that the dietary supplementation of this phytase significantly improved growth performance and bone mineralization in broiler chickens and piglets fed P-deficient diets, and increased retention of phosphorus (P) and calcium (Ca), and phytate-P degradation in excreta of broiler chickens in a dose-dependent manner.

In conclusion, there are no safety concerns using phytase HM as a feed additive and the phytase is well tolerated by broiler chickens and pigs. Further, phytase HM improves with high efficacy the growth performance in both broiler chickens and pigs.

Disulfide bond engineering of AppA phytase for increased thermostability requires co-expression of protein disulfide isomerase in Pichia pastoris

BACKGROUND

Phytases are widely used commercially as dietary supplements for swine and poultry to increase the digestibility of phytic acid. Enzyme development has focused on increasing thermostability to withstand the high temperatures during industrial steam pelleting. Increasing thermostability often reduces activity at gut temperatures and there remains a demand for improved phyases for a growing market.

RESULTS

In this work, we present a thermostable variant of the E. coli AppA phytase, ApV1, that contains an extra non-consecutive disulfide bond. Detailed biochemical characterisation of ApV1 showed similar activity to the wild type, with no statistical differences in k_cat and K_M for phytic acid or in the pH and temperature activity optima. Yet, it retained approximately 50% activity after incubations for 20 min at 65, 75 and 85 °C compared to almost full inactivation of the wild-type enzyme. Production of ApV1 in Pichia pastoris (Komagataella phaffi) was much lower than the wild-type enzyme due to the presence of the extra non-consecutive disulfide bond. Production bottlenecks were explored using bidirectional promoters for co-expression of folding chaperones. Co-expression of protein disulfide bond isomerase (Pdi) increased production of ApV1 by ~ 12-fold compared to expression without this folding catalyst and restored yields to similar levels seen with the wild-type enzyme.

CONCLUSIONS

Overall, the results show that protein engineering for enhanced enzymatic properties like thermostability may result in folding complexity and decreased production in microbial systems. Hence parallel development of improved production strains is imperative to achieve the desirable levels of recombinant protein for industrial processes.

In Vitro Evaluation of Probiotic Properties of Lactobacillus plantarum UBLP40 Isolated from Traditional Indigenous Fermented Food

In this study, traditional indigenous fermented food isolate Lactobacillus plantarum UBLP40 was screened for in vitro probiotic properties, antibiotic susceptibility, hemolytic activity, production of lactic acid, hydrogen peroxide, bile salt hydrolase and phytase, and antioxidative activity. Results showed that Lact. plantarum UBLP40 can survive simulated gastrointestinal conditions, adhere to mucin, possess a hydrophobic cell surface, ability to auto-aggregation, and possessed antimicrobial activity against Micrococcus luteus MTCC 106, methicillin-resistant Staphylococcus aureus subsp. aureus ATCC® BAA-1720, Pseudomonas aeruginosa MTCC 1688, and Escherichia coli MTCC 1687. Lact. plantarum UBLP40 produced 48.59 U/mg phytase and 1.78 ± 0.01 gm % lactic acid and showed the ability to produce hydrogen peroxide and bile salt hydrolase. Moreover, the usual antibiotic susceptible profile and non-hemolytic activity indicated the safety of the strain. The intracellular extract of UBLP40 showed 13.8 ± 1.4% (equivalent to ~8 µM butylated hydroxytoluene) α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, reducing activity equivalent to 1 µg L-cysteine, Fe²⁺ chelation equivalent to 5 µM ethylenediaminetetraacetic acid, and exhibited 17.73 ± 4.40 µM glutathione per gram of protein. In conclusion, this study demonstrates that Lact. plantarum UBLP40 is a potential probiotic candidate.

Synergistic effect of exogenous multi-enzyme and phytase on growth performance, nutrients digestibility, blood metabolites, intestinal microflora and morphology in broilers fed corn-wheat-soybean meal diets

OBJECTIVE

This study was conducted to investigate the synergistic effect of exogenous multienzyme and phytase on growth performance, nutrients digestibility, blood metabolites, intestinal microflora, and morphology in broilers fed corn-wheat-soybean meal diets.

METHODS

A 2×2 factorial design was used in this study. Four dietary treatments consisted of i) basal diets (corn-wheat-soybean meal based diets without multi-enzyme and phytase), ii) basal diets with phytase (0.05%), iii) basal diets with exogenous multi-enzyme (0.05%), and iv) basal diets with exogenous multi-enzyme including phytase (0.05%). A total of 480 broiler chickens (Ross 308 - one day old) were weighed and allotted to thirty-two cages (15 birds per cage), and chicks were randomly allocated to four dietary treatments.

RESULTS

The body weight gain and feed conversion rate were improved by supplementation of exogenous multi-enzyme containing phytase during the finisher period (p<0.05). The birds fed diets with exogenous multi-enzyme containing phytase had a significantly greater digestibility of dry matter, gross energy, crude protein, calcium, and phosphorus compared with birds fed non-supplemented diets (p<0.05). The chickens fed diets with exogenous multi-enzyme containing phytase showed a higher concentration of Ca and P in the serum (p<0.05). The population of Lactobacillus spp., Escherichia coli, and Clostridium were not affected in the ileum and cecum of chickens fed enzyme-supplemented diets. The dietary supplemental exogenous multi-enzyme containing phytase showed a significant improvement in villus height, crypt depth, and villus height and crypt depth ratio, compared to basal diets or dietary supplemental phytase (p<0.05).

CONCLUSION

The supplementation of the exogenous multi-enzyme containing phytase synergistically improved the growth performance, nutrients digestibility, and villus height of the small intestine of broiler chickens fed a corn-wheat-soybean meal based diets.

Exogenous phytase and xylanase supplementation of formulated diets for rohu (Labeo rohita): impact on haematology, histology and IGF I gene expression

The present study aims to delineate the effect of exogenous enzyme supplementation of fermented or non-fermented de-oiled rice bran (DORB) on haematology, histology and expression of IGF I gene expression of Labeo rohita. Four test diets, namely, T1 (DORB), T2 (fermented DORB), T3 (DORB+exogenous enzyme) and T4 (fermented DORB+exogenous enzyme) were formulated and fed to the L. rohita for a period of 60 days. The test diets T3 and T4 were supplemented with 0.1 g kg^-1 xylanase (16,000 U kg^-1) and 0.1 g kg^-1 phytase (500 U kg^-1) enzymes. A total of 120 juveniles of L. rohita (average weight 5.01 ± 0.02 g) were stocked in 12 rectangular tanks with 10 fish per tank in triplicates. At the end of the experiment, haematology, histology and IGF I gene expression of the different groups were analysed. The haemoglobin (Hb) content, RBC count and WBC count of L. rohita varied significantly (p < 0.05) among different groups. T3 diet-fed group had the highest Hb content, RBC count and WBC count as compared to the other groups. The MCV content was significantly (p < 0.05) lower in T3 group. The DORB type, exogenous enzyme supplementation and their interaction have no significant (p > 0.05) effect on MCH, MCHC and lymphocyte content of the cultured fish. The group which were fed T3 diet had significantly (p < 0.05) higher IGF-I gene expression as compared to other groups. The histological examination of liver revealed no pathological alteration of this organ. Similarly, there were no pathological changes observed in intestinal tissue in any dietary treatment group. Based on the findings of the present study, it is concluded that exogenous enzyme supplementation of DORB-based diets improves the physiological status and growth performances of Labeo rohita.

Synergistic optimisation of expression, folding, and secretion improves E. coli AppA phytase production in Pichia pastoris

Background

Pichia pastoris (Komagataella phaffii) is an important platform for heterologous protein production due to its growth to high cell density and outstanding secretory capabilities. Recent developments in synthetic biology have extended the toolbox for genetic engineering of P. pastoris to improve production strains. Yet, overloading the folding and secretion capacity of the cell by over-expression of recombinant proteins is still an issue and rational design of strains is critical to achieve cost-effective industrial manufacture. Several enzymes are commercially produced in P. pastoris, with phytases being one of the biggest on the global market. Phytases are ubiquitously used as a dietary supplement for swine and poultry to increase digestibility of phytic acid, the main form of phosphorous storage in grains.

Results

Potential bottlenecks for expression of E. coli AppA phytase in P. pastoris were explored by applying bidirectional promoters (BDPs) to express AppA together with folding chaperones, disulfide bond isomerases, trafficking proteins and a cytosolic redox metabolism protein. Additionally, transcriptional studies were used to provide insights into the expression profile of BDPs. A flavoprotein encoded by ERV2 that has not been characterised in P. pastoris was used to improve the expression of the phytase, indicating its role as an alternative pathway to ERO1. Subsequent AppA production increased by 2.90-fold compared to the expression from the state of the AOX1 promoter.

Discussion

The microbial production of important industrial enzymes in recombinant systems can be improved by applying newly available molecular tools. Overall, the work presented here on the optimisation of phytase production in P. pastoris contributes to the improved understanding of recombinant protein folding and secretion in this important yeast microbial production host.

Effectiveness of phytase pre-treatment on growth performance, nutrient digestibility and mineral status of common carp (Cyprinus carpio) juveniles fed Moringa by-product based diet

Several anti-nutritional substances are found in plant derivatives for example phytate, that make the nutrients and minerals unavailable to fish, hence leading to poor growth performance. Presence of the anti-nutrient factor such as phytate is a chelated compound and need enzyme for its breakdown and availability of nutrients to improve fish growth. This research work was performed to check the improvement of overall performance of Cyprinus carpio fingerlings by the help of phytase addition in Moringa oleifera by- products based diet. Combination of Moringa seed meal and Moringa leaf meal was utilized as test ingredient to formulate seven test feeds, containing graded levels of phytase (0, 500, 650, 800, 950, 1100 and 1250 FTU kg^-1). In feeding trial of 70 days, fingerlings were given feed two times in a day at the rate of 4% of wet weight of their bodies and faeces were collected. According to current results, it was found that growth performance parameters i.e. weight gain; 25 g, specific growth rate; 1.67 and feed conversion ratio; 1.10 were improved to maximum at 950 FTU kg^-1. Digestibility of nutrients (crude protein; 73%, crude fat; 71% and gross energy; 67%) and minerals absorption was also maximum (Ca; 70%, Zn; 66%, K; 74%, Mn; 66% and P; 71%) at 950 FTU kg^-1. Lowest growth efficiency, nutrient digestibility and mineral absorption were observed in fingerlings fed at control diet (0 FTU kg^-1). Results of the current study, proved that 950 FTU kg^-1 is the most optimum level of phytase to formulate economical and ecofriendly feed for improved growth of C. carpio fingerlings as it decreases the discharge of minerals and nutrients in water bodies.

Production and characterization of a novel, thermotolerant fungal phytase from agro-industrial byproducts for cattle feed

OBJECTIVE

The application of phytases helps in releasing bound phosphorus and other nutrients in cattle feed eventually reducing the need for supplementations. However, high production cost owing to the unavailability of cheaper sources of phytases has limited their usage in developing countries. Herein, firstly isolation, identification of a phytase from fungal isolate, Aspergillus niger NT7 was carried out followed by optimizing of all production parameters, through solid-state fermentation (SSF). Secondly, crude phytase was characterized and potential applicability of crude phytase was evaluated for dephytinization of wheat bran.

RESULTS

The highest phytase production (208.30 ± 0.22 U/gds) was achieved using wheat bran as cheap agro-industrial substrate for SSF. The various physiological parameters were optimized including inoculum age and level (3-day old inoculum and 15 × 10⁷ spores/ml), temperature (35 °C), a moistening agent (distilled water), medium pH (5), and supplementation of various biochemicals like sugar (Mannitol), nitrogen (ammonium sulphate) and detergent (Tween 80). Process optimization through one variable at a time (OVAT) approach increased the difference in productivity to more than 200%. The crude phytase of A. niger NT7 was thermostable, with optimal activity at 60 °C and also displayed optimal activity over a broad range of acidic pH. Further, enhancement in phytase activity was found specifically in the presence of Ca²⁺, Zn²⁺, and Co²⁺ ions, while other metal ions including Fe²⁺, Fe³⁺, Mn²⁺, Mg²⁺and Cu²⁺ inhibited its activity. Finally, the phytase showed efficient and sustained release of inorganic phosphate, proteins, and reducing sugars (> 60 h) from livestock feed.

CONCLUSION

Overall, our report highlights the production of an efficient and thermotolerant phytase with potential as a low-cost animal feed supplement.

Over-processed meat and bone meal and phytase effects on broilers challenged with subclinical necrotic enteritis: Part 2. Inositol phosphate esters hydrolysis, intestinal permeability, hematology, jejunal gene expression and intestinal morphology

This study investigated the hypothesis that feeding broilers over-processed meat and bone meal (MBM) would impair gut health in the absence of phytase and in turn, affect inositol phosphate (inositol x-phosphate, IPx: IP3, IP4, IP5 and IP6) ester hydrolysis, intestinal permeability, hematology, jejunal gene expression and intestinal morphology during necrotic enteritis (NE). Ross 308 male broilers (n = 768) were assigned to one of 8 dietary treatments in a 2 × 2 × 2 factorial arrangement, with 6 replicate pens per diet and 16 birds per pen in a completely randomized design. Factors were: NE challenge (no or yes), phytase level (500 or 5,000 FTU/kg) and MBM processing (as-received or over-processed). For the NE challenge, half of the birds were challenged with field strains of Eimeria spp. on d 9 and 10⁸ CFU/mL of Clostridium perfringens strain EHE-NE18 on d 14 and 15. A 3-way challenge, phytase and MBM processing interaction was detected for IP5 (P < 0.05) and IP6 (P < 0.05) levels in the ileum. Birds fed low phytase had increased IP5 and IP6 in unchallenged birds only when diets contained over-processed MBM. Challenge with NE increased intestinal permeability as measured by serum fluorescein isothiocyanate dextran (FITC-d; P < 0.001), increased white blood cells (WBC; P < 0.001), decreased mean corpuscular volume (MCV; P < 0.001) and mean corpuscular hemoglobin (MCH; P < 0.05), and decreased crypt-to-villi ratio (P < 0.05). The over-processed MBM reduced the villi-to-crypt ratio (P < 0.05). A 3-way challenge × phytase × MBM processing interaction was detected for mucin 2 (MUC-2) expression (P < 0.05) where only in unchallenged birds fed over-processed MBM did high phytase reduce MUC-2 expression. A lower expression of aminopeptidase N (APN; P < 0.001) and vitamin D receptor (VDR; P < 0.001) were recorded in NE challenged birds. In conclusion, NE has a negative impact on the gut and hematology of broilers, but its effect on phytate hydrolysis is minimal.

Effects of phytase-supplemented fermentation and household processing on the nutritional quality of Lathyrus sativus L. seeds

Grass pea (Lathyrus sativus L.) is commonly consumed in cooked, fermented, and roasted forms in Ethiopia. However, the impacts of household processing practices on its nutrients, antinutrients, and toxic compounds have not been adequately studied. Therefore, the effects of household processing and fermentation in the presence and absence of a phytase on the contents of β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), myo-inositol phosphates, crude protein, minerals and the in vitro bioaccessibility were investigated. Fermentation exhibited a significant decline in β-ODAP (13.0-62.0%) and phytate (7.3-90.5%) irrespective of the presence of phytase. Pressure and pan cooking after discarding the soaking water resulted in a 27.0 and 16.2% reduction in β-ODAP. A 30% reduction in phytate was observed during germination followed by roasting. In addition, germination resulted in a significant (p < 0.05) increase in crude protein. Germination and germination followed by roasting resulted in the highest Fe bioaccessibilities (more than 25 fold higher compared to untreated samples) followed by pressure cooking and soaking. Processing also improved Zn bioaccessibilities by 50.0% (soaked seed without soaking water), 22.5% (soaked seed with soaking water), and 4.3% (germination). Thus, the processing technologies applied were capable of reducing the content of phytate (InsP6) and β-ODAP with a concomitant increase in mineral bioaccessibilities. Processing of grass peas could therefore contribute to their more widespread utilization.

Effects of Saccharomyces cerevisiae and phytase co-fermentation of wheat bran on growth, antioxidation, immunity and intestinal morphology in broilers

OBJECTIVE

The aim of this study was to investigate the effects of different amounts of wheat bran (WB) inclusion and postbiotics form by Saccharomyces cerevisiae and phytase cofermented wheat bran (FWB) on the growth performance and health status of broilers.

METHODS

Study randomly allocated a total of 300 male broilers to a control and 4 treatment groups (5% WB, 5% FWB, 10% WB, and 10% FWB inclusion, respectively) with each pen having 20 broilers and 3 pens per treatment.

RESULTS

The WB does not contain enzymes, but there are 152.8, 549.2, 289.5, and 147.1 U/g dry matter xylanase, protease, cellulase and β-glucanase in FWB, respectively. Furthermore, FWB can decrease nitric oxide release of lipopolysaccharide stimulated chicken peripheral blood mononuclear cells by about two times. Results show that 10% FWB inclusion had significantly the highest weight gain (WG) at 1 to 21 d; 5% FWB had the lowest feed conversion rate at 22 to 35 d; 10% WB and 10% FWB inclusion have the highest villus height and Lactobacillus spp. number in caecum; and both 5% and 10% FWB can increase ash content in femurs. Compared to control group, all treatments increase mucin 2, and tight junction (TJ), such as occludin, claudin-1, zonula occludens-1, and mRNA expression in ileum by at least 5 folds. In chicken peripheral blood mononuclear cells, nicotinamide adenine dinucleotide phosphate-oxidase-1 mRNA expression decreases from 2 to 5 times, and glutamate-cysteine ligase catalytic subunit mRNA expression also increases in all treatment groups compared to control group. The mRNA expression of pro-inflammatory cytokines, including interleukin-6 (IL-6), nuclear factor-κB, and IL-1β, decreases in 5% and 10% FWB groups compared to control group.

CONCLUSION

To summarize, both WB and FWB inclusion in broilers diets increase TJ mRNA expression and anti-oxidation and anti-inflammation, but up to 10% FWB groups have better WG in different stages of broiler development.