Nitrogen Supplementation Research Articles

Optimization of Growth Conditions for Oxalate Decarboxylase Production from Pseudomonas sp. OXDC12 and in vitro Inhibition of Calcium Oxalate Crystallization by Oxalate Decarboxylase

Background: Kidney stones have become a common disease worldwide, and their incidence and recurrence rates have drastically increased over the past few decades. Oxalate decarboxylase (OxDC) enzyme which catalyzes the disproportionation reaction of oxalate monoanions into formate and CO2 could exhibit significant potential in the treatment of hyperoxaluria. Objective: The present work describes isolation and screening of new OxDC producing bacterial strain from oxalate-rich soils and one-factor-at-a-time (OFAT) and response surface methodology (RSM) statistical approaches were used to optimize the production media to obtain an improved intracellular OxDC production. Methods and Results: An OxDC producing bacterial strain, isolated from spinach soil sample(s), was identified to be Pseudomonas sp. OXDC12 by 16S rRNA sequencing. The OFAT approach was used to determine the effect of supplementation of carbon, nitrogen, and other physical conditions like pH, temperature, etc. on intracellular OxDC production by Pseudomonas sp. OXDC12. The three factors screened by Plackett Burman design (PBD) were further used by the central composite design (CCD) approach of RSM to determine their interactive effects on OxDC production. The anti-urolithiatic activity of the enzyme OxDC was determined by carrying out in vitro calcium oxalate crystallization in the presence and absence of OxDC. The factorial values selected by 23 CCD for OxDC were temperature 30ºC, manganese ion concentration 5 mmol l-1, and inoculum size 3.25% (v/v). The highest predicted value of OxDC was 5.7 U ml-1 while the actual value obtained was 6.7 U ml-1 which was 79.1% and 2.92 fold greater than the initial activity of OxDC produced by Pseudomonas sp. OXDC12. As depicted by the light micrographs, OxDC displayed a significant reduction in the crystallization and formation of calcium oxalate stones as compared to the control under in vitro conditions. Conclusion: OFAT and RSM statistical optimization approaches led to improved OxDC production with a final activity of 6.7 U/mL and a 2.92 fold increase in the enzyme activity. The study suggests that OFAT and RSM optimization approaches significantly enhanced OxDC production from Pseudomonas sp. OXDC12. The enzyme may serve as a potential therapeutic agent for hyperoxaluria or kidney stones as it significantly inhibited the formation of calcium oxalate crystals under in vitro conditions.

Influence of activated biochar pellet fertilizer application on greenhouse gas emissions and carbon sequestration in rice (Oryza sativa L.) production

Supplemental activated biochar pellet fertilizers (ABPFs) were evaluated as a method to sequester carbon and reduce greenhouse gas (GHG) emissions, and improve rice production. The evaluated treatments were a control (standard cultivation method, no additives applied), activated rice hull biochar pellets with 40% of N (ARHBP-40%), and activated palm biochar pellets with 40% of N (APBP-40%). The N supplied by the ARHBP-40% and APBP-40% treatments reduced the need for supplemental inorganic nitrogen (N) fertilizer by 60 percent. The ARHBP-40% treatment sequestered as much as 1.23 tonne ha−1 compared to 0.89 tonne ha−1 in the control during the rice-growing season. In terms of greenhouse gas (GHG) emissions, CH4 emissions were not significantly different (p > 0.05) between the control and the ARHBP-40%, while the lowest N2O emissions (0.002 kg ha−1) were observed in the ARHBP-40% during the crop season. Additionally, GHG (CO2-equiv.) emissions from the ARHBP-40% application were reduced by 10 kg ha−1 compared to the control. Plant height in the control was relatively high compared to others, but grain yield was not significantly different among the treatments. The application of the ARHBP-40% can mitigate greenhouse gas emissions and enhance carbon sequestration in crop fields, and ABPFs can increase N use efficiency and contribute to sustainable agriculture.

The influence of nitrogen supplementation on lipase production by Aspergillus niger using palm oil mill effluent

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Synergistic anti-oxidative effects of Pongamia pinnata against nickel mediated by Rhizobium pisi and Ochrobacterium pseudogrignonense

Nickel is widely spread by different anthropogenic activities and shows toxicity for plant growth and development. Whether rhizobia symbiotically fix nitrogen can eliminate or reduce nickel toxic effect on plant or not is still unknown. This study was aimed to investigate the effect of different rhizobia genus inoculation on growth, nitrogen fixing ability, metal accumulation and enzymatic antioxidative balance of Pongamia pinnnaa. Inoculation with Rhizobium pisi and Ochrobacterium pseudogrignonense increased the all the growth parameters both in 0 and 40 mg/kg nickel as comparison with control. Only shoot length increased in presence of nitrogen as compared with no supply of nitrogen. Nitrogen content also increased both in rhizobia inoculation as compared to no nitrogen supply and non-inoculation control, respectively. Nickel uptake was higher in shoots and leaves but lower in roots in case of inoculation as compared to non-inoculation control. Rhizobia inoculation improved the plant antioxidant capacity by increasing the activity of enzymatic scavengers catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate (GR). However, 40 mg/kg of nickel adding showed mostly effect on the activity CAT, SOD, POD in leaves. All the enzymatic activity showed a significant increase in absence of nitrogen supply as compared nitrogen supply. Our results suggested that rhizobia inoculation effectively mediated nickel stress for legume plants by increasing nitrogen supplement and inducing antioxidant capacity.

Effects of Supplement Irrigation and Nitrogen Application Levels on Soil Carbon–Nitrogen Content and Yield of One-Year Double Cropping Maize in Subtropical Region

Inappropriate irrigation conditions and nitrogen application can negatively affect soil carbon–nitrogen content and yield of maize, as well as can lead to underground water pollution and soil degradation. A two year (2018, 2019) field experiment was carried out to determine the effect of irrigation and N, alone and in combination on maize grain yield, grain nitrogen content, soil inorganic N and MBC of one-year double cropping maize (Zea mays L.) in a subtropical region. Split plot design was adopted, with main plots consisting of two water regimes: drip irrigation (drip irrigation to keep soil water content no less than 70% of maximum field capacity) and rainfed (no irrigation during growing period). Split-plot treatments consisted of five nitrogen application levels, including 0 (N0), 150 (N150), 200 (N200), 250 (N250), and 300 kg/ha (N300). The results of two-year field experiment showed that soil irrigation nitrogen interaction had a significant influence on the all measured parameters. In detail, soil NH4+-N and NO3−-N content, total nitrogen (TN), soil organic carbon (SOC) and grain nitrogen contents under the combined treatment of N250 and supplementary irrigation were higher relative to other treatments. Compared with rainfed, maize yield, thousand grains weight (TGW) and harvest index increased by 22.0%, 7.7%, and 15.2% under supplemental irrigation. Yield and TGW N300 were 287 kg/ha and 3.1 g higher than those of N250, and yield and TGW of N250 were 59.4% and 23.1% higher than those of N0, respectively. The yield of spring maize was 24.0% significantly higher than that of autumn maize. Therefore, we suggested that 250 kg/ha nitrogen application fertilizer combined with supplementary irrigation can improve soil fertility and annual maize yield in subtropical one-year double cropping region.

Evaluation of Bioethanol Production from a Mixed Fruit Waste by Wickerhamomyces sp. UFFS-CE-3.1.2

The use of fruit residues from domestic consumption for energy purposes is a perspective of innovation in the search for a more sustainable fuel, due to the low cost of this biomass, combined with its large amounts of generation, which has sugars readily available in its composition and does not require process pretreatment hydrolysis complexes of the material. This work evaluated residues of melon, pineapple, banana, apple, and mango, to compose a mixture of fruit waste (MFW), simulating a household waste for bioethanol production by a non-conventional yeast Wickerhamomyces sp. UFFS-CE-3.1.2. Sugar extraction was optimized by experimental design (MFW: 12% g dry mass v−1; 25 °C; 5 min) and resulted in the liberation of 36.32 ± 0.72 g L−1 fermentable sugar. MFW was used for alcoholic fermentation with and without nitrogen supplementation (urea and yeast extract). The results demonstrated that it is not necessary for the supplementation, making the process more economically viable. The maximum ethanol productivity (2.50±0.06 g L−1 h−1) was achieved in 9 h of the operation. The MFW extracted is an alternative for the bioethanol process as low cost and straightforward, adapted for different fruit residues, and used as a unique or diluent medium in the biorefinery context. Moreover, non-conventional yeast demonstrated the more new one in this study that explores the potential of yeast recently isolated.

Efficient bioethanol production from date palm (Phoenix dactylifera L.) sap by a newly isolated Saccharomyces cerevisiae X19G2

In this research, 54 newly isolated strains of yeast from various microhabitats were screened in order to explore their potential for bioethanol production through bioconversion of date palm sap (DPS), as a renewable raw material. The highest ethanol concentration of 58.7 ± 0.23 g/L was achieved by the newly selected Saccharomyces cerevisiae strain X19G2 under anaerobic conditions. The effects of nitrogen supplementation, inoculum size and incubation temperature on bioethanol production from DPS by this strain were investigated. Bioethanol yield (0.43 ± 0.01 g/g consumed sugars) and ethanol productivity (1.49 ± 0.11 g/L/h) increased significantly when a mixture of ammonium sulfate and yeast extract (1:1) were used as nitrogen sources at 30 °C. Subsequently, batch and fed-batch (FB) fermentation were performed in a 2 L bioreactor. The highest ethanol yield was achieved in the FB experiment, reaching 0.48 g/g consumed sugars, which corresponded to over 90 % of the maximum theoretical yield. Based on these findings, the minimum bioethanol production potential using DPS was estimated to be approximately 11000 L per hectare of palm trees. This study indicated that DPS is a highly promising feedstock for bioethanol production by the yeast S. cerevisiae strain X19G2 with economic benefits for industrial scale production.

Assessing the impact of nitrogen supplementation in oats across multiple growth locations and years with targeted phenotyping and high-resolution metabolite profiling approaches

Oats (Avena sativa L.) are a healthy food, being high in dietary fibre (e.g. β-glucans), antioxidants, minerals, and vitamins. Understanding the effect of variety and crop management on nutritional quality is important. The response of four oat varieties to increased nitrogen levels was investigated across multiple locations and years with respect to yield, grain quality and metabolites (assessed via GC- and LC- MS). A novel high-resolution UHPLC-PDA-MS/MS method was developed, providing improved metabolite enrichment, resolution, and identification. The combined phenotyping approach revealed that, amino acid levels were increased by nitrogen supplementation, as were total protein and nitrogen containing lipid levels, whereas health-beneficial avenanthramides were decreased. Although nitrogen addition significantly increased grain yield and β-glucan content, supporting increasing the total nitrogen levels recommended within agricultural guidelines, oat varietal choice as well as negative impacts upon health beneficial secondary metabolites and the environmental burdens associated with nitrogen fertilisation, require further consideration.

Nitrogen supplementation ameliorates product quality and quantity during high cell density bioreactor studies of Pichia pastoris: A case study with proteolysis prone streptokinase

Streptokinase is a well-established cost-effective therapeutic molecule for thrombo-embolic complications. In the current study, a tag-free variant of streptokinase with a native N-terminus (N-rSK) was developed using the Pichia expression system. A three-copy clone was screened that secreted 1062 mg/L of N-rSK in the complex medium at shake flask level. The biologically active (67,552.61 IU/mg) N-rSK recovered by anion exchange chromatography was predicted to contain 15.43% α-helices, 26.43% β-sheets. The fermentation run in a complex medium yielded a poor quality product due to excessive N-rSK degradation. Therefore, modified basal salt medium was also employed during fermentation operations to reduce the proteolytic processing of the recombinant product. The concomitant feeding of 1 g/L/h soya flour hydrolysate with methanol during the protein synthesis phase reduced the proteolysis and yielded 2.29 g/L of N-rSK. The fermentation medium was also supplemented with urea during growth and induction phases. The combined feeding approach of nitrogen-rich soya flour hydrolysate and urea during bioreactor operations showed significant improvement in protein stability and resulted in a 4-fold increase in N-rSK concentration to a level of 4.03 g/L over shake flask. Under optimized conditions, the volumetric productivity and specific product yield were 52.33 mg/L/h and 33.24 mg/g DCW, respectively.

The white-rot fungus, Phanerochaete chrysosporium, under combinatorial stress produces variable oil profiles following analysis of secondary metabolites.

The effects of combinatorial stress on lipid production in Phanerochaete chrysosporium remain understudied. This species of white-rot fungi was cultivated on solid-state media while under variable levels of known abiotic and biotic stressors to establish the effect upon fungal oil profiles. Environmental stressors induced upon the fungus included the following: temperature, nutrient limitation and interspecies competition to assess impact upon oil profiles. Fatty acid type and its concentration were determined using analytical methods of gas chromatography and mass spectrometry. Growth rate under stress was established using high-performance liquid chromatography with ergosterol as the biomarker. Fungi grown on solid-state agar were able to simultaneously produce short- and long-chain fatty acids which appeared to be influenced by nutritional composition as well as temperature. Addition of nitrogen supplements increased the growth rate, but lipid dynamics remained unchanged. Introducing competition-induced stress had significantly altered the production of certain fatty acids beyond that of the monoculture while under nutrient-limiting conditions. Linoleic acid concentrations, for example, increased from an average of 885ngμl-1 at monoculture towards 13820ngμl-1 at co-culture, following 7days of incubation. Interspecies competition produced the most notable impact on lipid production for solid-state media cultivated fungi while the addition of nitrogen supplementation presented growth and lipid accumulation to be uncorrelated. Combinatorial stress therefore influences the yield of overall lipid production as well as the number of intermediate fatty acids produced, deriving similar oil profiles to the composition of vegetable and fish oils. Fungal secondary metabolism remains highly sensitive following combinatorial stress. The outcome impacts the research towards optimizing fungal oil profiles for biomass and nutrition. Future investigations on fungal stress tolerance mechanisms need to address these environmental factors throughout the experimental design.

Cool‐season lawn performance as influenced by ‘Microclover’ inclusion and supplemental nitrogen

AbstractLawns require a steady supply of nitrogen (N) to maintain green color and seasonal shoot density. Excess N fertilization can lead to surface and groundwater contamination, suggesting a need for alternative turf fertilization strategies that reduce the reliance on frequent N applications. Grass‐legume mixtures may be one solution since legumes, like white clover (Trifolium repens L.), biologically fix atmospheric N and add it to the soil via mineralization. This field study evaluated the growth, appearance and persistence of a cool‐season grass and grass‐legume mixture containing a low growing Trifolium repens, ‘Microclover’ (MC) with and without supplemental N fertilization (0 vs. 98 kg N ha−1 yr−1) over two growing seasons. Turf with MC and receiving supplemental N produced the most dry matter yield (DMY) 15583 kg ha−1 and the highest mean visual appearance. By contrast, unfertilized turf without MC produced the least DMY, 3815 kg ha−1, and the poorest appearance, which lacked vigor and was negatively affected by leaf blighting diseases. The unfertilized turf with MC produced moderate growth, 8754 kg ha−1, with an acceptable appearance. Clover populations decreased over time in both the unfertilized and fertilized grass‐legume mixtures but less so where supplemental N was not applied. This decline in clover could possibly be remedied by periodic overseeding. In summary, these results suggest that a cool‐season grass‐clover lawn mixture can provide a persistent and visually acceptable lawn that would require less reliance on supplemental N fertilization.

In vitro ruminal fermentation and enteric methane production of tropical forage added nitrogen or nitrogen plus starch

The aim was to evaluate the effects of supplementation with nitrogen and nitrogen plus starch in tropical grass hay (TGH) on neutral detergent fiber (NDF) and dry matter (DM) in vitro digestibility, pH, ammoniacal nitrogen (NH3-N), volatile fatty acids (VFA), methane (CH4), and CO2 emissions. The study was divided into two sets, first, evaluating the level of nitrogen to be supplemented: control (CON -TGH, 68 g CP/kg DM), low nitrogen (LN- TGH +90 g CP/kg DM), and high nitrogen (HN- TGH + 130 g CP/kg DM). The second set aimed to evaluate the level of nitrogen and starch to be supplemented: low nitrogen and low starch (LNLS - TGH + LN + 10% forage weight in starch supplementation-SS), high nitrogen and low starch (HNLS- TGH + HN + 10% SS), low nitrogen and high starch (LNHS - TGH + LN + 20% SS) and high nitrogen and high starch (HNHS - TGH + HN + 20% SS). Samples were incubated in serum bottles (50 mL) and each run was replicated 4 times. The measurements of NDF and DM digestibility, NH3-N concentration, and pH were performed at 3, 6, 9, 12, 24, 36, 48, 72, and 96 h, and CH4, CO2, and VFA were evaluated after 24 h. All data were analyzed using a completely randomized design in factorial scheme. Differences across treatments were investigated using five contrasts. In the first set, two contrasts were used to evaluate the nitrogen effect (linear and quadratic). In the second set, three contrasts were used to evaluate the effects of nitrogen, starch, and interaction between them. In the first set, there was linear nitrogen effect on NDF digestibility (p = 0.037), pH (p = 0.001), NH3-N (mg/dL; p = 0.001) and CO2 (g/g digestible DM; p = 0.042). Quadratic nitrogen effect was observed on CO2 production (mL, g/g DM and g/digestible DM; p < 0.050). In the second set, nitrogen supplementation improved undegradable NDF fraction, pH and NH3-H (mg/dL; p < 0.050) levels. The starch supplementation increased propionate, butyrate (mmol/d; p < 0.050), and CO2 production (mL and g/g DM; p = 0.004). There was no nitrogen and nitrogen plus starch effect on CH4 production. In conclusion, nitrogen supplementation increased NDF digestibility, NH3-N concentration, and pH. Moreover, the supplementation with nitrogen (130 g/kg DM) plus starch (20% of TGH) provided greater VFA production. However, despite the benefits of nitrogen or nitrogen plus starch supplementation on nutritional parameters, they were not effective to reduce CH4 and CO2 production.

Thioredoxin pathway in Anabaena sp. PCC 7120: activity of NADPH-thioredoxin reductase C.

To understand the physiological role of NADPH-thioredoxin reductase C (NTRC) in cyanobacteria, we investigated an NTRC-deficient mutant strain of Anabaena sp., PCC 7120, cultivated under different regimes of nitrogen supplementation and light exposure. The deletion of ntrC did not induce a change in the cell structure and metabolic pathways. However, time-dependent changes in the abundance of specific proteins and metabolites were observed. A decrease in chlorophyll a was correlated with a decrease in chlorophyll a biosynthesis enzymes and photosystem I subunits. The deletion of ntrC led to a deregulation of nitrogen metabolism, including the NtcA accumulation and heterocyst-specific proteins while nitrate ions were available in the culture medium. Interestingly, this deletion resulted in a redox imbalance, indicated by higher peroxide levels, higher catalase activity and the induction of chaperones such as MsrA. Surprisingly, the antioxidant protein 2-CysPrx was downregulated. The deficiency in ntrC also resulted in the accumulation of metabolites such as 6-phosphogluconate, ADP and ATP. Higher levels of NADP+ and NADPH partly correlated with higher G6PDH activity. Rather than impacting protein expression levels, NTRC appears to be involved in the direct regulation of enzymes, especially during the dark-to-light transition period.

Using Si-rich materials for increasing fodder grass quality and quantity

Improvement of forage quality is one of the essential issues to enhance livestock productivity. Bahiagrass is a popular fodder plant used as pasture species and for hay production, but it lacks the nutritional quality. In greenhouse experiment, the effect of silicon (Si) (calcium silicate and amorphous silicon dioxide) and nitrogen (ammonium nitrate) supplementation on bahiagrass growth and protein content was evaluated. Both types of fertilizers significantly increased the biomass and crude protein content in leaves of bahiagrass. Higher effect was obtained when Si was applied together with nitrogen. The increases were 78 to 100% for biomass and 57 to 59% for crude protein content. Considering that improved plant Si nutrition mitigates the negative effects of biotic and abiotic stresses, the Si involvement into fertilizer management strategy in fodder crops could be efficient for maintaining productivity and quality.

Candida tropicalis as a Promising Oleaginous Yeast for Olive Mill Wastewater Bioconversion

Olive mill wastewater (OMW), which is generated during olive oil production, has detrimental effects on the environment due to its high organic load and phenolic compounds content. OMW is difficult to biodegrade, but represents a valuable resource of nutrients for microbial growth. In this study, yeast strains were screened for their growth on phenolic compounds usually found in OMW and responsible for antimicrobial effects. Candida tropicalis ATCC 750 demonstrated an extraordinary capacity to grow in phenolics and was chosen for further experiments with OMW-based medium. The effects of nitrogen supplementation, the pH, and the stirring rate on cellular growth, OMW-components consumption, and added-value compounds production were studied in batch cultures in Erlenmeyer flasks and in a bioreactor. Candida tropicalis was able to reduce 68% of the organic load (chemical oxygen demand) and 39% of the total phenols of OMW in optimized conditions in bioreactor experiments, producing lipase (203 U·L−1) and protease (1105 U·L−1). Moreover, intracellular lipids were accumulated, most significantly under nitrogen-limited conditions, which is common in this type of wastewater. The high potential of C. tropicalis to detoxify OMW and produce added-value compounds from it makes this process an alternative approach to other conventional processes of OMW treatment.

Effect of soil and foliar supplementation of nitrogen, boron and salicylic acid on quality of cucumber (Cucumis sativus L.) in alfisols of Konkan

The field experiment was conducted to assess the effect of soil and foliar supplementation of nitrogen, boron and salicylic acid either alone or in combinations applied along with the recommended dose of fertilizers (135:60:30 NPK kg ha-1) on quality and nutrient content of cucumber (Cucumis sativus L.) in acid Alfisols of Konkan at Research and Education Farm, Department of Agricultural Botany, College of Agriculture, Dr Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, Dist. Ratnagiri (M.S.) during the Summer season of 2018 in Randomized Block Design (RBD) comprising ten treatment combinations replicated thrice. The results revealed that the quality parameters of cucumber grown in acid Alfisols of Konkan viz., TSS, reducing sugar, total sugar and titratable acidity; nitrogen, phosphorus, potassium and boron content in plants significantly increased and recorded the maximum values due to the application of recommended dose of fertilizer (135:60:30 kg ha-1) + foliar spray of nitrogen through urea (1%) + soil application of boron through borax @ 2 kg ha-1 + foliar spray of salicylic acid (0.2%) along with 15 t ha-1 FYM.

Production of Bacterial Amylase and Evaluation for Starch Hydrolysis

In starch degrading industry, the first step to be performed is gelatinization of starch granules at elevated temperature. This process tends to form a viscose suspension, thus making mixing and pumping a huge challenge. Therefore, to lower the viscosity of starch paste thermostable enzymes are added for breaking down the polysaccharides into oligosaccharides by a process known as liquefaction. Therefore, the availability of these enzymes can be considered a prerequisite to start successful starch liquefaction and saccharification industry. The main objective of this study was, therefore, to produce efficient microbial amylolytic enzymes for starch hydrolysis. One bacterial isolate designated as BACC 2107 was isolated from locally collected samples. The enzyme has optimum activity at pH of 5.0 and 70°C. The addition of calcium in the reaction mixture was shown to stabilize the enzyme. The isolate BACC 2107 was able to grow under solid-state fermentation (SSF) using wheat bran as a solid substrate. Optimum enzyme production was recorded at 32°C, and at 120 h of incubation and at a moisture content of 75%. Addition of peptone to the SSF medium as an organic nitrogen supplement enhanced enzyme production. The enzyme was used to hydrolyze a 25% (w/v) of starch at 70°C and pH 5.0, and the resulting hydrolysate was analyzed on TLC plates. After 4 h hydrolysis, the TLC chromatogram showed the release of glucose, maltose, maltotriose, and other oligosaccharides, indicating that the enzyme is endo-acting alpha-amylase. The results of this study show that amylase from BACC 2107 has a good potential to be used in starch liquefaction and saccharification processes. The ability of the isolate to grow and produce the enzyme under SSF using cheap agro-industrial wastes could help to greatly reduce the production cost of the enzyme.

Effect of weed management practices and organic sources of nitrogen supplementation on weed density and yield of wheat

The different weed control methods (two hand weeding at 25 and 45 days after sowing (DAS) and one hand weeding at 25 DAS along with unweeded control ), organic sources of nitrogen (vermicompost, poultry manure, city manure and FYM) and their interaction were compared for their efficiency on various weed species and yield of wheat. Two hand weeding (W2) gave significantly maximum weed control. This was followed by one hand weeding at 25 DAS and control. These weed control methods significantly enhanced the yield and yield components of wheat. Among organic sources of nitrogen vermicompost (M1) recorded minimum weed density, weed dry weight and maximum yield, followed by poultry manure, city manure and FYM.

Combination of non-protein nitrogen and N‑carbamylglutamate supplementation improves growth performance, nutrient digestibility and carcass characteristics in finishing pigs fed low protein diets

This study was conducted to determine whether supplemental non-protein nitrogen (NPN) and/or N-carbamylglutamate (NCG) in the low protein diet enhance the growth performance, nutrient digestibility and carcass characteristics of finishing pigs. A total of 150 (Duroc boar× (Landrace boar × Yorkshire) sow) finishing pigs (initially body weight 74.3 ± 3.8 kg) were blocked by weight and sex, and allotted to one 5 treatments with 6 replicate pens (3 barrows and 2 gilts per pen). Diets were normal protein diet (NP, crude protein (CP) 136.4 g/kg), low protein diet (LP, CP 111.4 g/kg), LP supplemented with 0.8 g/kg NCG (LNCG, CP 111.8 g/kg), LP supplemented with 7.1 g/kg NPN (LNPN, CP 119.8 g/kg), and LP supplemented with 7.1 g/kg NPN and 0.8 g/kg NCG (LNN, CP 120.3 g/kg) and fed to pigs for 40 days. At the end of the experiment, 30 pigs (one barrow per pen) were slaughtered to evaluate carcass traits and meat quality. Compared to the LP group, the combination of NPN and NCG supplementation significantly increased (P < 0.05) the average daily gain (ADG) of finishing pigs. The coefficient of apparent total tract digestibility (CATTD) of gross energy (GE), crude protein (CP) and acid detergent fiber (ADF) in LP group were lower (P < 0.05) than that in the NP group, while LNN group significantly increased (P < 0.05) the CATTD of GE, CP, ether extraction (EE), neutral detergent fiber (aNDF) and ADF when compared with LP group. Similarly, the concentrations of arginine, isoleucine, threonine, glycine, serine, tyrosine, and citrulline in the serum of pigs fed LNN diet were higher (P < 0.05) than that in those pigs fed LP diet. The carcass traits and meat quality did not differ between the NP group and the LP group, but the combination of NPN and NCG supplementation in LP diet significantly increased (P < 0.05) the concentrations of intramuscular fat. Compared to NP group, LP group increased (P < 0.05) the concentration of C16:0 and decreased (P < 0.05) the concentrations of C20:4, C22:6 and polyunsaturated fatty acid (PUFA) in the M. longissimus lumborum of finishing pigs, and LNN group further decreased (P < 0.05) the concentrations of C18:2 and PUFA when compared with the LP group. This study indicates that dietary supplementation with both NPN and NCG has important complementary advantages in improving the growth performance and meat quality of finishing pigs fed low protein diet balanced with amino acids.

Carotenoid Production by Rhodosporidium paludigenum Using Orange Peel Extract as Substrate

Carotenoids are fat-soluble pigments that have various benefits in health and beauty. The demand and market of carotenoids are increasing; thus, the faster and cheaper biological production of these pigments using microorganisms is desired. In this study, the optimum medium pH and nitrogen concentration for carotenoid production by Rhodosporidium ( R. ) paludigenum using orange peel extract as substrate were determined. The soluble sugars from orange peels were extracted using distilled water at 100 °C. The yeast inoculum was cultivated in Yeast Peptone Dextrose (YPD) media before fermentation. The independent variables in the fermentation factorial design included initial medium pH (5; 6; and 7) and nitrogen concentration (0; 1; and 1.75 g/L urea in the medium). The decrease in reducing sugar concentration and the increase in biomass dry weight during fermentation demonstrated carbon source consumption by R. paludigenum for growth and carotenoid production. On the sixth day of fermentation (D6), the culture was harvested for the total carotenoid extraction and determination. The highest total carotenoid yield (107.63 µg/g) was achieved by the treatment group with an initial medium pH of 6 without nitrogen supplementation. This result indicated the orange peel extract potential as a substrate for carotenoid production using R. paludigenum as a workhorse. This was the first reported research in natural carotenoid generation using R. paludigenum (strain InaCC Y-236) locally isolated in Indonesia as the producer and orange peel extract as the substrate. Thus, this research would enrich the microbial carotenoid exploration and waste valorization to value-added products at the same time. The study can then be developed further and upscaled for industrial applications.Â