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This study aimed to investigate the possibility of extracting protein from chicken feathers. We conducted our research in a controlled laboratory environment, where we carefully washed feathers collected from white broiler chickens. The feathers were ground and hydrolyzed using a 1:10 ratio of 0.2 eq/L of standard sodium hydroxide (NaOH) solution and 28.5 % sodium hydrosulfite (NaHSO3) solutions. The hydrolyzed solution was further processed in a 90 °C water bath for 6 h using a rotor stirrer. After this, the solution was neutralized with 99 % acetic acid (CH3COOH) and filtered. The filtrate was dialyzed with distilled water in a cellophane membrane bag for 24 h. Following dialysis, we obtained two samples of the dried and ground protein. The first sample was subjected to physicochemical analysis, while the second sample was treated with 5 % H2O2 before analysis. Our analysis, conducted using the Kjeldahl and liquid chromatography methods, revealed that 68–78 % of proteins were synthesized. The study of free amino acids found that the highest indicator, which belongs to 38–40 % of cysteine, asparagine, glutamine, and tryptophan in the protein, failed because of alkaline hydrolysis. However, samples 1 and 2 of the protein containing 17 free amino acids were comparable, further validating our findings.

This study examined the nitrogen content in moss samples collected across Macedonia over a 15-year period (2005, 2010, 2015 and 2020) from 72 consistent sampling locations. The nitrogen content was determined using the Kjeldahl method, providing insight into the trends of atmospheric nitrogen deposition across different regions. Descriptive statistical analyses, including spatial distribution maps, were used to compare the temporal variations and regional nitrogen levels. In addition, box-plots (P25–P75) and whiskers (P5–P95) were constructed to provide a comprehensive view of the variability across different tectonic units and zones, allowing for an in-depth understanding of the spatial distribution of nitrogen across the country. The study revealed that the median nitrogen content in moss samples decreased from 1.21% in 2005 to 1.04% in 2015, followed by a slight increase to 1.07% in 2020. The highest nitrogen concentrations were consistently found in areas with heavy agricultural activities and high traffic volumes, indicating the direct impact of these anthropogenic factors. The comparisons across regions and geological zones also highlighted the substantial variation in nitrogen levels, reflecting the diverse environmental pressures in different parts of Macedonia. This long-term analysis not only offers valuable insights into the trends in nitrogen pollution but also underlines the necessity for targeted policy interventions, particularly in the regions where nitrogen levels remain persistently high.

The possibility of formulating nitrogen, phosphorus and potassium (NPK) biofertilizer from ashes of waste organic materials such as chicken feathers, bone and banana peels is investigated in this study by first subjecting the agricultural waste to 80-250 heat in a muffle furnace to produce ash. Kjeldatherm block digestion unit, UV spectrophotometer, and flame photometers, respectively helped in measuring the concentrations of N, P and K inherent in the fertilizer precursors as well as in 5 formulated blends (i.e., A, B, C, D & E). It was discovered that NPK in the single substrate and blends favorably compared with standard NPK 20:10:10 chemical fertilizer to some extent. Among single material fertilizer sources, feather ash with 0.179:1:0.134 NPK and bone ash with 0.009:1:0.021 NPK had the closest nutrient content with the standard, showing potential promise. On the other hand, Blend E is the same as the standard, followed by Blend A, B, D and C, which are hierarchically close in elemental composition to the standard. The choice of these biofertilizers is dependent on their nutrient compositions, the type of crops to be grown, and the soil mineral requirements. Most importantly, different NPK ratio organic fertilizers produced in this study can competitively be produced in a large scale to address huge costs associated with the NPK 20:10:10 standard commercial fertilizer. Blend E (NPK 20:10:10) can be formulated locally by farmers in rural areas easily using this particular agricultural residue or a host of other confirmed farm wastes.

Objective:The aim of this study is to determine the total protein and free amino acid content of Artemisia abrotanum L. in two different periods, the pre-blooming and blooming periods.Methods:The Dumas and Kjeldahl methods were applied comparatively to determine the total protein amount. In addition, after the sample was extracted with water:methanol (80:20) containing 0.1% formic acid, free amino acids were determined in liquid chromatography-mass spectrometer.Results:By using the Dumas method, the % nitrogen content was found to be 2.10 and 2.20, in the pre-blooming and blooming period samples. The results obtained by applying the Kjeldahl method are 2.16 and 2.25, respectively. The total protein content was calculated from the nitrogen content of the plant by using a nitrogen conversion factor of 6.25. The total free amino acid content in the pre-blooming and blooming period was found to 453.41 and 606.18 mg/100 g dried plant respectively.Conclusion:Since the total protein and free amino acid content of Artemisia abrotanum L. is higher during the blooming period, it should be preferred to be harvested during this period.

Proteins are the second most essential macromolecules after nucleic acids. This article aimed at the comparative analysis of extraction methods and nutritional benefits of milk and dairy products. Proteins form the body mass and perform several crucial tasks that include acting as a catalyst and carrying out different metabolic reactions in the body. Furthermore, protein acts as a transporter, transmits nerve impulses, provides mechanical support or immune protection, and controls growth. Several sources of proteins are present, but milk holds an important place due to its biological activities. The considerable health benefits of milk and its products are due to proteins. Yoghurt and cheese have significant importance among milk products. Proteins of milk and its products can be extracted by pH adjustment through homogenisation, centrifugation, and deproteinisation. There are several techniques for identifying and quantifying milk and product proteins. The Kjeldahl and spectrophotometric methods are the most widely used methods for quantifying proteins in milk and its products. Furthermore, these techniques include electrophoresis and chromatographic methods, including native gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), urea-PAGE, capillary electrophoresis, and isoelectric focusing. A few are chromatographic methods like reverse-phase high-performance liquid chromatography (RP-HPLC), size exclusion chromatography, and ion-exchange chromatography. Each technique has its advantages as well as disadvantages. The selection of the process depends upon the type of protein. The extracted proteins from milk and its products have many health or therapeutic effects that exhibit antimicrobial, antiproliferative, antioxidant, antihypertensive, anticancer, antiviral, and immunomodulatory effects. Yoghurt has prime importance among milk products because of its therapeutic effects and more protein.

Modification of cotton with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) has been studied extensively and can be operated by means of exhaustion, cold pad-batch, and continuous and pad-steam methods. Most of the research addresses the cationization of cotton fabric after bleaching or mercerization, or during the mercerization process. In our studies, we performed a comparison of the cationization effects on raw, enzymatic, and alkali-scoured cotton knitted fabrics applying CHPTAC according to the exhaustion method. The charge density of the cotton surface was measured using a Muetek Particle Charge Detector and a “back titration” method with polyelectrolytes. These results were compared with the nitrogen content in the samples, K/S measurements of tested samples after dyeing with anionic dye (Acid Yellow 194), and other physicochemical parameters such as weight loss, whiteness, and wettability.

The method based on the determination of the amount of active amino groups using o-Phthaldialdehyde (OPA method) can be applied in practice to assess accurately the degree of proteolysis in cheeses. The work establishes that the OPA method gives results that strictly correlate (R2 > 0.80, p < 0.01) with the results of assessing the degree of proteolysis by the Kjeldahl method. The results of the OPA method, expressed in the absorption intensity of the colored sample at a wavelength of 340 nm (OD340), can be converted to the content of soluble nitrogenous substances in cheese (WSN), using the calibration relationship between these indicators.The accuracy of the calibration relationship between WSN and OD340 can be increased (R2 > 0.91, p< 0.01) when using the OPA method in relation to a homogeneous group of cheeses produced by the same technology using the same type of milk clotting enzyme and lactic acid starter culture and having a similar shape of the molecular mass distribution of proteolysis products.The OPA method can be used to assess the content of proteolysis products, which form cheese flavor, in EMС. The results of assessing the degree of proteolysis by the OPA method (OD340) are proportional to both the total content of soluble nitrogen and the proportion of nitrogenous substances in it with a mass of less than 0.5 kDa, which make the greatest contribution to the formation of cheese flavor.The advantage of using the OPA method for assessing proteolysis in cheeses and EMC instead of the Kjeldahl method is a simpler measurement procedure and the possibility of studying more samples in less time.

Protein is one of the most abundant substances in plants and plays a major role in human health hence standardization of its analytical quantification method is essential. Various methods for protein quantification exist, such as Kjeldahl, Bradford, Lowry, bicinchoninic acid assay (BCA), Biuret, and total amino acid content methods. These methods are widely applied; however, the development of the rapid and efficient method is the need of the time hence the objective of this research was to analyze and comparing compare the modification of the Kjeldahl method for the determination of protein content in oilseed crops. The study was performed to improve the sample preparation method (processing and digestion) for protein quantification. Generally, the method initially requires homogenization of grains to a fine flour, which involves time and increases the risk of sample cross-contamination and partial loss of oil from the sample during grinding. Moreover at times, it becomes challenging to homogenize oil seeds to fine flour due to high oil content. However, in the present research, the whole grain was digested in place of grounded flour to accomplish quick protein quantification and compared it with the flour matrix of different oil seeds. To further reduce the digestion time and avoid frothing, we have used the modified digestion mixture. The developed method was statistically validated using analysis of variance (ANOVA), Pearson correlation reliability test, paired T-test, and different types of plot analysis. The validation of the sample preparation method in protein quantification demonstrated non-significant differences that the protein content from whole grain of all the five oilseed crops shows 100% non-significant results compared with the flour matrix in both the digestion mixtures. The developed novel method could be used to prepare the sample for protein analysis and reduces the overall analysis time while ensuring the accuracy of the results.

BACKGROUND By measuring the nitrogen content in plant fruits, the growth status of plants can be grasped and important information for improving the yield of high-quality fruits can be provided. At present, the traditional Kjeldahl method is used to determine nitrogen in plant fruits. The main steps are digestion, distillation and titration. The digestion time of traditional method is 90 minutes, and the titration and distillation time is 10-20 minutes. The determination process is complicated and produces errors, which is not suitable for the analysis of large amounts of plant fruits. OBJECTIVES To shorten the analysis and determination time of total nitrogen in plant fruit samples, improve work efficiency, avoid artificial errors, and solve the problems of sample splashing and white smoke escaping during digestion. METHODS A graphite digestion instrument was used for digestion. Concentrated sulfuric acid and a catalyst were added, the reflux plug was capped, and an automatic nitrogen determination instrument was used for analysis. RESULTS The sample did not splash and the white smoke did not escape. The digestion time was 50 minutes and the distillation time was 3 minutes. The reagent consumption was reduced by 2mL. The relative error and relative standard deviation were less than 5%. CONCLUSIONS The established method meets the needs of the laboratory to quickly and accurately detect total nitrogen in large amounts of plant samples. It has been applied in the detailed survey project of the China geological survey bidding project and the detailed investigation of the soil pollution status of agricultural land in Hebei Province.

Abstract Background Cassia sophera Linn is a medicinally important plant belonging to the family of Caesalpiniaceae. The whole part of the plant is used as traditional folk medicine and is reported to possess analgesic, anticonvulsant, antioxidant, anti-inflammatory, hepatoprotective, and antiasthmatic activity. The present communication attempt is to evaluate fatty acids from different parts of the plant by GC-MS spectrophotometer and total protein content by the Kjeldahl method and to quantify some active constituents, i.e., alkaloid, saponin, and flavonoid. Results From fatty acid compositions of the petroleum ether extract of leaves, stems, flowers, and seeds of this plant grown in Bangladesh, 22 compounds from leaves, 8 compounds from stems, 9 compounds from flowers, and 12 compounds from seeds were identified. The main fatty acid was arachidic acid (38.66%) from leaves. Linoleic acid (40.12% and 42.40%) was found mainly from stems and seeds, whereas from flowers, it was docosadienoic acid (27.14%). Conclusion The findings from the present study showed that the protein content for seeds has higher value (19.20%) than other parts of the plant. Also the present investigation showed that different parts of the plant contain phytochemicals in appreciable quantities in the form of flavonoids, alkaloids, and saponins. The flavonoid and alkaloid content of leaves showed higher value. But the stem part showed higher saponin content than other parts of the plant.

Protein scarcity is the most vital cause of long-lasting diseases and even untimely deaths in some developing nations. The application of protein in food is advantageous from the point of view of non-toxicity, biocompatibility, and dietary benefits. This study aimed to determine the protein contents of the sprouts of Vigna radiates (mung beans), Lens culinaris (lentils), and Cicer arietinum (chickpeas) using the Kjeldahl and Lowry methods. The results obtained from the Kjeldahl method identified protein concentrations of 2.54, 2.63, and 2.19%, whereas the Lowry method results identified protein concentrations of 2.96%, 4.10%, and 1.6% in mung beans, lentils, and chickpeas, respectively. In both the methods, lentils were found to have the highest amount of protein followed by mung beans and chickpeas. Both the Kjeldahl and Lowry methods demonstrated good protein values and low variation in the protein amount in the analyzed samples. Furthermore, the methods had greater sensitivity and comparable experimental variability. The outcomes revealed that assays can be applied for protein analysis in legumes. In the context of a lack of suitable standard procedures for evaluating legumes’ compositions, the present study is suitable for food control laboratories. In addition, the studied samples represent a significant source of protein and can be used to fulfil the daily requirements for protein intake and other food applications.

Being attractive for insects, non-genetically modified rapeseed is valuable for maintaining environmental biodiversity. Primarily, the rapeseed is an important industrial crop which is used for production of vegetable oil. Oil extraction from rapeseeds results in the generation of substantial amounts of rapeseed meal which is used either as a protein rich feed additive or as a source for preparation of protein containing ingredients for food industry. Both applications require frequent evaluation of protein content. Although Kjeldahl method is considered standard, it is not appropriate for routine evaluation of protein content in protein extracts. The aim of the study was to evaluate suitability of biuret and Bradford methods for protein quantification in rapeseed meal extracts. After consecutive triple extraction of proteins with water, 5% NaCl, 70% ethyl alcohol and 0.1 N NaOH, protein evaluation of each albumin, globulin, prolamin and glutelin extraction aliquot demonstrated overall lower protein content by Bradford method compared to biuret method. The most pronounced differences in protein content were observed with prolamin fraction where three fold higher protein concentrations in each extraction aliquot was observed when biuret method was applied for the evaluation. Comparative quantification of the total protein of each of the four fractions followed a similar trend of lower protein content evaluation by Bradford method. Overall results indicated biuret method as more suitable for protein quantification in rapeseed meal extracts which was confirmed by comparison with data obtained by Kjeldahl method.

Glanders is a contagious and fatal disease of horses, donkeys, and mules, caused by infection with the bacterium Burkholderia mallei. The pathogen causes nodules and ulcerations in the upper respiratory tract and lungs. Glanders is transmissible to humans by direct contact with diseased animals or with infected or contaminated material. In the untreated acute disease, the mortality rate can reach 95% within 3 weeks Malein PPD - the diagnostic product contain max 2mg/ml Burkholderia mallei. The amount of protein in the biological product "Malein PPD" is measured as nitrogen from protein molecule, applying the Kjeldahl (method determination of nitrogen by sulphuric acid digestion). The validation study aims to demonstrate the determination of the protein of the Malein PPD, by sulphuric acid digestion, it is an appropriate analytical method, reproducible and meets the quality requirements of diagnostic reagents. The paper establishes the performance characteristics of the method considered and identify the factors that influence these characteristics. The method for determining the concentration of protein, by the Kjeldahl method is considered valid if the results obtained for each validation parameter are within the admissibility criteria.The validation procedure includes details on protocol working to determine the protein of the Malein PPD, validation criteria, experimental results, mathematical calculations.

The majority of dry pet food currently on the market is produced using fresh meats (FMs) and especially meat meals (MMs) as the main protein source. The transport and storage conditions of the raw materials, together with thermal and mechanical treatments in the case of MMs, may result in undesirable alterations of food products and their protein content. This study was conducted to analyze the protein component of three different kinds of raw materials used for dry pet food production, i.e., chicken, pork, and salmon. The quantitative analysis of the protein component was determined using the traditional Kjeldahl method and near-infrared (NIR) spectroscopy, and an alternative method, i.e., the Bradford assay, while the qualitative analysis was performed through SDS-PAGE, followed by Coomassie Blue staining. The amino acid (AA) profile was also evaluated by quadrupole time-of-flight liquid chromatography/mass spectrometry (Q-TOF LC/MS). In addition, the digestibility was tested through in vitro gastric and small intestine digestion simulation. Statistical analysis was performed by the Student’s t-test, and data are reported as mean ± SEM, n = 10 (p < 0.05). The results showed that the MMs are lower in quality compared to FMs, both in terms of protein bioavailability and digestibility, having a lower soluble protein (SP) content (chicken MM = 8.6 g SP/100 g dry sample; pork MM = 6.2 g SP/100 g dry sample; salmon MM = 7.9 g SP/100 g dry sample) compared to FMs (chicken FM = 14.6 g SP/100 g dry sample; pork FM = 15.1 g SP/100 g dry sample; salmon FM = 13.7 g SP/100 g dry sample). FMs appear, therefore, to be higher-quality ingredients for pet food production. Moreover, the Bradford assay proved to be a quick and simple method to better estimate protein bioavailability in the raw materials used for dry pet food production, thanks to its correlation with the in vitro digestibility.

The deterioration of natural resources in agricultural activities, has motivated the search for new alternatives to enrich the soil with macro and micro nutrients sustainably, for the benefit of future generations, just as you think about the conservation and maintenance of water, avoiding eutrophication problems by the accumulation of fertilizers (nitrates and nitrites) leached and deposited in natural sources, for this purpose they have been measured several agro ecological options that provide proper nutrition and a delicate ecological balance; in this investigation at field level in maize cultivation and different states it applied dose of azolla as a natural source of nitrogen to enrich the soil in the canton Cevallos, Tungurahua province. Anabaena floors of the town, based on the state of azolla and the level established for such preparation, the states of azolla. Six mixtures were prepared substrates azolla studied were: Dry A1 and A2 in the fresh state; the doses were established in relation to the volume of azolla against soil volume used: (0.5: 1) (0.75: 1) and (1: 1). The data collected were plant height and percentage of nitrogen in dry matter at 15, 30, 60 and 90 days. All this in order to establish the amount of nitrogen contributed by azolla as biofertilizer in growing corn. The best results were presented at the A1D3 (azolla dry-Dose 1: 1) treatment given plant height 15.02 cm at 15 days, 35.88 cm 30 days, 53.22 cm 60 66.12 days and 90 days; to 0.54% nitrogen percentage at 15 days, 0.90% at 30 days, 1.68% at 60 days and 2.08% after 90 days. In conclusion, the use of Azolla as a bio-fertilizer rich in nitrogen is feasible, as has been demonstrated in this research that the corn plant benefits from the contribution of this material, improving sustainable agricultural practices. It is recommended to expand this research in the same crop or other commercially important crops until the end of its production cycle, to report the results of these.

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatàgrass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatàgrass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

Determination of crude protein (CP) is important for nutritional characterization of ruminant diets. The objective of this work was to evaluate the results of CP in grasses and concentrated feeds by the Kjeldahl method, based on digestion with acid solution and heating, distillation with addition of a base and heating and titration with standard solution of sulfuric acid, and the Dumas method, based on the release of nitrogen by high temperature combustion in pure oxygen, which is measured by thermal conductivity and converted to CP equivalent. The experiment was conducted at the Animal Nutrition Reference Laboratory of the Institute of Zootechnics (IZ), Nova Odessa, SP, Brazil, in a completely randomized design with six replicates. Samples of six feedstuffs were evaluated, three grasses: Urochloa grass (Urochloa decumbens), Tobiatã grass (Megathyrsus maximus cv. Tobiata), and star grass (Cynodon plectostachyus), and three concentrated feeds: sorghum bicolor grain (Sorghum bicolor), corn gluten meal and fish meal. Crude protein concentration was evaluated using PROC GLM SAS® and the Tukeytest (p

The application of organic materials as fertilizers is a common practice in clean production and organic systems, however, there is not enough technical criteria to measure the right dose. In this sense, overdoses or underdosing may occurs affecting the profitability of the production system. For this reason, it was used seven organic materials, commonly used in the Sabana de Bogotá, three derived from crop residues (Sagaro Compost, Compost CIAA (ICCA), soil-aid®) and four derived from animal waste (chicken, pork, rabbit and ground lombris derived humus). It was determined its potentially mineralizable nitrogen and the rate of nitrogen mineralization using the incubation method. The experimental design was completely randomized with eight treatments (seven organic materials and a control), and three repetitions for a total of 24 experimental units. The measurement was performed at weekly intervals from week one to week nine, after incubation. Waste materials derived from animals were generally better than those from plant residues in the N mineralization process, as is the case of rabbit-derived humus that release 5.197 mg·kg-1 of mineral nitrogen, a value that represents 20% of initial total Nitrogen. The degree of adjustment of logarithmic model was more than 80% (R2> 0.80) in 86% of the evaluated materials.