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The study aimed to evaluate the effects of supplements containing soybean meal or extruded urea as true protein or non-protein nitrogen sources on supplement intake, performance, and cost of beef steers in the water-dry and water transition. In a completely randomised design, thirty-six Nellore steers with an average of 200 kg body weight (BW) kept in four paddocks, distributed into two treatments with nine animals each. Supplements containing non-protein nitrogen (extruded urea) or true protein (soybean meal) for two seasons were formulated. Data were analysed using ANOVA, with significance set at P ≤ 0.05 and trends at P ≤ 0.10. Animals fed supplement with true protein had greater supplement intake and greater total dry matter intake, which allowed higher average daily gain (ADG) and final BW. Likewise, during the wet-dry transition period, animals fed true protein had greater intake (total and supplement), ADG, TWG, and final BW. Regarding production costs, the use of soybean meal supplements had higher supplementation costs but also had higher income to animals and area. Despite having lower feed costs, the total replacement is not recommended of true protein by non-protein nitrogen sources in supplements for steers in the growing phase. [ABSTRACT FROM AUTHOR]

For producing a combination of urea with acetylated lignosulfonate in the pellet form, the urea release was studied under real conditions in the livestock rumen. Morphological, chemical, and mechanical features of slow-release urea combination with acetylated lignosulfonate and comparing it with lignosulfonate, acetylated lignosulfonate, and urea were studied. The produced pellets with weight percentages (10, 30, 50, and 65) showed the potential of acetylated lignosulfonate in water. For the study of the amount of nitrogen release, slow-release urea (a combination of 65 wt% of acetylated lignosulfonate with 35 wt% of urea) together with three other experimental ratio samples including control ration without urea, urea control supplement ration and Nitro-Za inside the livestock rumen were studied and measured during a period of 0.5 to 24 h. The changes range in Nitro-Za ammonia nitrogen concentration and the slow-release substance are aligned and similar. The slow-release substance belonging to the urea diet combined with acetylated lignosulfonate showed better performance from the fourth hour. The study results showed positive results regarding supplementing the feed ration with slow-release urea compared to urea and comparable to Nitro-Za. [ABSTRACT FROM AUTHOR]

The objective was to investigate the effects of increasing levels of extruded urea (EU) in the supplementation of lambs grazing. Crossbred Texel lambs (n = 45) were used and kept in continuous grazing in paddocks with Brachiaria spp. The design used was completely randomised, with five of EU replacing soybean meal (0; 6; 12; 18 and 24 g/kg) and two sexes (male and female). The animals were slaughtered, and qualitative and quantitative evaluations of the carcass, non-carcass components, meat quality and chemical composition were carried out. There was an interaction between level*sex for ether extract (EE) and crude protein (CP), so than the meat of the females from the treatment without EU had a higher content of EE than that used EU and the meat of the males from the treatments with 12 g and 24 g 100 kg−1 LW higher levels of CP than other treatments. For all measurements performed up to 18 g 100 kg−1 LW of EU replacing bran and soy, the results were promising, and can be fed to finishing lambs under grazing, without negatively influencing most of the carcass characteristics, components non-carcass, meat quality and chemical composition. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen (N) distribution in plants is intricately linked to key physiological functions, including respiration, photosynthesis, structural development, and nitrogen storage. However, the specific effects of different N morphologies on N accumulation and plant growth are poorly understood. Our research specifically focused on determining how different N morphologies affect N absorption and biomass accumulation. Methods: This study elucidated the impact of different application rates (CK: 0 g N/plant; T1: 4 g N/plant; T2: 8 g N/plant) of N fertilizer on N and biomass accumulation in tobacco cultivars Hongda and K326 at different growth stages. Results: Ourfindings emphasize the critical role of N distribution invarious plantparts, including leaves, stems, and roots, in determining the complexmechanisms of N and biomass accumulation in tobacco. We found that in relation tototalN, a greater ratio of water-soluble N (Nw) in leaves facilitated N accumulation in leaves. In contrast, an increased ratio of SDS (detergent)-insoluble N (Nin-SDS) in leaves and non-protein N (Nnp) in roots hindered this increase. Additionally, our results indicate that a greater proportion of Nnp in leaves has a negative impact on biomass accumulation in leaves. Furthermore, elevated levels of Nin-SDS, Nw, and Nnp in roots, and Nnp in leaves adversely affected biomass accumulation in tobacco leaves. The Hongda cultivar exhibited greater biomass and N accumulation abilities as compared to K326. Conclusions: Our findings highlight the significant role of distribution of N morphologies on plant growth, as well as N and biomass accumulation in tobacco plants. Understanding N distribution allows farmers to optimize N application, minimizing environmental losses and maximizing yield for specific cultivars. These insights advance sustainable agriculture by promoting efficient resource use and reducing environmental impact. [ABSTRACT FROM AUTHOR]

Abstract Background Breast milk contains various crucial nutrients and biologically active substances and is ideal for newborns. This study aimed to analyze the composition of breast milk from mothers of premature and full-term infants and its influences on the growth of infants. Methods Infant-mother dyads examined at our Hospital (March 2016 to May 2017) were included. Milk was collected at 0–1 month, 2–3 months, and 5–6 months and analyzed using a MIRIS human milk analyzer. Z-scores of weight-for-length (WLZ), weight-for-age (WAZ), and length-for-age (LAZ) were calculated. Results This study included full-term (> 37 weeks of gestation, n = 177) and premature (

Introduction: The shortage of feed, caused by the limitation and reduction of water resources, is the biggest challenge for the country's livestock industry. Every year, more than 20 million tons of by-products from the main agricultural production remain in the country, which are mainly used as animal feed. Agricultural by-products, which exceed the production of forage crops many times over, are valuable resources that can replace conventional feeds in animal nutrition. Due to their low protein content and low digestibility, they need to be processed. For almost a century, different processing methods have been used in many countries depending on the conditions and facilities, but unfortunately, the majority of these materials are still used raw and unprocessed as animal feed in the country, which is a waste of resources. Straw processing is carried out by various physical, chemical, and biological methods or a combination of these methods, with ammoniation being the most important chemical method. The use of ammonia gas for this purpose can facilitate and accelerate processing, especially with large quantities of by-products. This research was carried out to study the efficacy and economics of the method of ammonization of straw with ammonia gas and the use of the ammonia product in the diet of fattening calves. Materials and methods: Ammoniated wheat straw was prepared with ammonia gas at three weight percent of the dry matter of straw at 30% moisture by stacking method, and the chemical composition, digestibility, and gas production of the ammonia-containing product were determined. In the second phase, 30 Simmental crossbred fattening calves with an initial weight of 249.5±8.9 were divided into two control and experimental groups and for each group, considering three replicates of five calves for each group. Normal straw was used in the control group, and it was replaced by ammoniated straw in the experimental group. The duration of the trial was eight months, during which the weight gain of the calves was determined every 30 days, and the dry matter was consumed daily. Dry matter consumption, daily weight gain, feed conversion ratio, and the cost of weight gain of calves were determined and compared between the two groups. Results and discussion: The ammonia treatment of straw increased crude protein content in the ammoniated straw from 4.78% to 12.65%, and the amount of NDF and hemicellulose also decreased in ammoniated straw (from 71.33 to 66.80%, and from 30.75 to 26.25%, respectively), while the amount of ADF increased (from 38.7 to 41.20%). The ammonia treatment of straw increased the gas production per 24 hours from 25.71 mL to 38.06 mL and the estimated metabolizable energy from 5.69 to 6.8 MJ per kilogram of dry matter. The ammonia treatment improved the digestibility of dry matter (from 45.0 to 78.75%) and organic matter of straw (from 42.35 to 80.27%). Substituting normal straw for ammoniated straw in the diet of fattening calves increased daily dry matter consumption from 8.66 kg to 8.99 kg (P<0.01), daily weight gains from 1.33 kg to 1.48 kg, and average weight at the end of the fattening period from 423.98 kg to 440.67 kg (P<0.01), and improved feed conversion ratio from 6.43 to 6.01 (P<0.01). In addition, the use of ammoniated straw reduced the price of ration from 71230 Rials to 69210 Rials and the cost of feed for each kilogram of animal weight gain from 458008.9 Rials to 415952.1 Rials. Conclusions: Ammoniation of straw with ammonia gas increased the metabolizable energy, crude protein, and digestibility of straw. The use of ammonia gas for this purpose increased the speed, ease, and efficiency of processing, making it suitable for processing large quantities of straw. The profitability of this method depends on the cost of the ammonia product, in particular the price of ammonia gas and its transportation costs. At the national level and from a macroeconomic perspective, this method increased the digestible nutrients of agricultural residues (metabolizable energy and crude protein), it is, in a sense, a type of food production by increasing productivity and without the consumption of water and other agricultural inputs. It provides more nutrients for livestock, which reduces dependence on traditional feed, reduces competition between humans and livestock for food, protects the environment, and makes production more sustainable. [ABSTRACT FROM AUTHOR]

Inclusion of a source of non-protein nitrogen (NPN) may improve essential amino acid (EAA) and nitrogen (N) utilization in N-limiting diets. Growing barrows (20.4 ± 0.5 kg) were randomly assigned to 1 of 10 dietary treatments (n = 9 pigs/treatment) in nine blocks. Diets contained no ammonium phosphate (NAP) or 1.7% ammonium phosphate (AP) to have an EAA-N:total N ratio of 0.36 and 0.33, respectively, with graded levels of dietary lysine (Lys; 0.8%, 0.9%, 1.0%, 1.1%, and 1.2% standardized ileal digestible (SID)). Following a 7-day dietary adaptation, a 4-day N-balance collection period was conducted. Blood samples were obtained on day 2 of the collection period. Nitrogen retention (NR) increased and urinary N output decreased with inclusion of NPN and increasing Lys (P < 0.01). Plasma urea N decreased with increasing Lys (P < 0.05). Total plasma EAA content was reduced with NPN supplementation (P < 0.05), while content of Arg, Asp, Gln, and Glu was increased (P < 0.01). The linear breakpoint model indicated that NR was maximized at 1.00% SID Lys in NAP-fed pigs and at 1.09% SID Lys in AP-fed pigs. These results indicate that diets deficient in dietary N reduce NR and Lys requirement, which were in turn increased with NPN supplementation. [ABSTRACT FROM AUTHOR]

Background: Breast milk contains various crucial nutrients and biologically active substances and is ideal for newborns. This study aimed to analyze the composition of breast milk from mothers of premature and full-term infants and its influences on the growth of infants. Methods: Infant-mother dyads examined at our Hospital (March 2016 to May 2017) were included. Milk was collected at 0–1 month, 2–3 months, and 5–6 months and analyzed using a MIRIS human milk analyzer. Z-scores of weight-for-length (WLZ), weight-for-age (WAZ), and length-for-age (LAZ) were calculated. Results: This study included full-term (> 37 weeks of gestation, n = 177) and premature (< 37 weeks, n = 94) infant-mother dyads. The premature infants showed higher ΔWAZ, ΔLAZ, and ΔWLZ from infancy to toddlerhood for the physical growth speed, compared with term infants (P < 0.001). All proteins and true protein components of breast milk decreased with infants' age (P < 0.001). For premature and full-term infants, differences in ΔWAZ and ΔLAZ from birth to infancy and the difference in ΔLAZ, WAZ, and LAZ in toddlerhood were positively associated with non-protein nitrogen (NPN) (all P < 0.05), while the Z-score differences in ΔWLZ from birth to infancy were negatively associated with NPN (all P < 0.05). For premature babies, from birth to infancy stage, ΔWAZ was positively correlated with NPN and carbohydrates while negatively correlated with dry matter (all P < 0.05), and ΔLAZ correlated with NPN (β = 0.428, P = 0.005). Conclusion: Breastfeeding helped premature infants compensatory growth when compared to term infants. Whileduring early infancy stage ΔWLZ gain was negatively associated with increased amounts of NPN in breast milk. This might mean although NPN increase the Z-scores of weight-for-age and length-for-age, with no rise in adipose tissue mass. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the feeding behavior of dairy cows fed sorghum silage diets with urea levels. This study was conducted after approval by the Ethics Committee on Animal Use of the State University of Piauí (approval n. 0356/19). Five 3/4 Holstein × 1/4 Gir dairy cows in the middle-third of lactation, at an average age of 60 months and an average body weight of 518 kg ± 52 kg, were allocated to five treatments in a 5 × 5 Latin square design. Treatments U-50, U-75, U-100, U-125 and U-150 corresponded to 51.2, 77.7, 104.1, 140.8 and 173.5 g of urea consumed per day, respectively. Behavioral assessments were undertaken on the 20th day of each period, with observations performed at every five minutes over 24 h. Five evaluations were carried out, totaling 120 h of evaluations. Data were analyzed by variance and regression analysis procedures (SAEG, version 9.0), adopting the significance level of 0.05. The urea levels in the concentrate did not influence (P<0.05) the feeding behavior of lactating cows fed sorghum silage diets. The cows expended, on average, 270.6 min/day feeding, 511.8 min/day ruminating and 657.8 min/day performing other activities. Total chewing time was not influenced (P<0.5). No effect was observed (P<0.5) for the bite-related aspects. Dietary inclusion of urea levels (51.2 to 173.5 g of urea consumed per day) did not influence the rumination aspects. [ABSTRACT FROM AUTHOR]

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Introduction: Lack of animal feed, especially with development of industrial methods of animal husbandry waste in many parts of the world, has led farmers and researchers to try identifying and using agricultural and livestock waste and new food sources for animal nutrition, including poultry manure and urea is mentioned in the diet of ruminants. Due to the fact that no research has been done on the effect of barley grain processing methods and non-protein nitrogen sources in the diet on rumen degradability, gas production and microbial protein synthesis in sheep, the present study was conducted.Materials and methods: This experiment was conducted in a completely randomized design with seven treatments including a control treatment containing whole barley grain (without milling) and without urea and chicken manure, treatments 2, 3 and 4 containing processing method of milling, filling and pelleting with a certain level of urea, respectively. (1%) And treatments 5, 6 and 7 containing processing methods of milling, filling and pelleting with a certain level of poultry manure (12%) were performed on sheep. Each treatment consisted of 5 fattening lambs at the age of 3 months 24±1 which were kept individually in separate cages for 14 days of acclimatization period and 84 days of fattening period. In the second experiment, rumen degradability of dry matter, crude protein and NDF of experimental diets were measured using a nylon bag method with 3 fistulated male sheep that were fed in the maintenance level. Extent and rate of gas production were done based on Menk and Stingas. The NH3-N concentration was determined following the Broderick and Kang (1980) technique. Purine derivatives and was measured by the method of Chen and Gomes (1995). Rumen fluid was collected for 5 consecutive days in the end of each period and ruminal fermentation parameters containing pH and NH3-N and were determined. Urine of sheep was collected end of each period for 5 days and microbial protein synthesis was estimated by measuring purine base. Data were analyzed using SAS software version 9.9 (54) using GLM procedure.Results and Discussion: The apparent digestibility of dry matter and organic matter were significantly different, and the control treatment (whole barley grain without urea and poultry manure) had the highest apparent digestibility. Digestibility in non-fibrous carbohydrates was significantly different, so that treatment 5 (processing method of milling with poultry manure) had the highest apparent digestibility. Different parameters of degradability of dry matter, crude protein and insoluble fibers in neutral detergent of experimental treatments indicated significant differences between treatments (P

We conducted two experiments. The first aimed to obtain and characterize microparticles of slow-release urea (SRU) using calcium alginate as the encapsulating agent. The second experiment evaluated their inclusion in sheep diets. In the first experiment, four treatments from a completely randomized design were employed to develop an SRU through the ionic gelification technique testing two drying methods (oven and lyophilizer) and addition or no of sulfur (S): SRU oven-dried with sulfur (MUSO) and without sulfur (MUO), SRU freeze-dried/lyophilized with (MUSL), and without sulfur (MUL). MUO exhibited better yield and encapsulation efficiency among these formulations than the others. Therefore, the second experiment was conducted to compare free urea (U) as control and three proportions (1%, 1.5%, and 2% of total dry matter) of MUO in the diet of sheep. Twenty-four non-castrated male Santa Ines lambs, with an average body weight of 22 ± 3.0 kg, were used and distributed in a completely randomized design with four treatments and six replications. The inclusion of 1% alginate-encapsulated urea (MUO1%) resulted in higher dry matter (DM) intake than free urea (p ≤ 0.05). MUO2% inclusion promoted higher NDF digestibility than U and MUO1%. MUO1% showed higher DM than MUO2% and higher NFC digestibility than U and MUO2% (p ≤ 0.05). Sheep fed MUO1.5% and MUO2% exhibited similar nutrient intake and digestibility. Sheep receiving MUO1% had higher N-intake, N-urinary, N-excretion total, N-digested, and N-retained compared to U. Sheep fed MUO1% showed greater N-retained (as % ingested and digested), microbial protein production, and efficiency when compared to other treatments (p ≤ 0.05). MUO2% addition (SRU) promoted the lowest microbial protein production and efficiency in sheep. MUO dietary inclusion increased feeding time and reduced idleness time compared to U, regardless of the MUO level (p ≤ 0.05). Adding MUO1% improved the intake efficiency of DM and NDF and resulted in more feed boli than the other MUO levels (p ≤ 0.05). Sheep receiving U had (4 h after fending) higher NH3-N, pH, and blood urea nitrogen (BUN) and lower TGL serum compared to sheep fed MUO (p ≤ 0.05), without significant difference among MUO levels (p > 0.05), except NH3-N was higher in MUO1.5% and MUO2% compared to MUO1.0%. The external ionic gelation technique proved suitable for urea microencapsulation in calcium alginate (3%), demonstrating high quality, efficiency, and yield. MUO represents a promising slow-release urea for ruminants and is recommended for sheep diets at an inclusion level of 1.0%. This inclusion level improves intake efficiency and nutrient digestibility, increases rumen nitrogen retention, and reduces BUN without compromising sheep health. [ABSTRACT FROM AUTHOR]

Introduction: The lack of animal feed resources and the increase in animal feed costs relative to the total production costs have created challenges in supplying society with animal protein. Therefore, correctly estimating the nutritional value of feed, especially protein sources, can be an important step in meeting the needs of livestock and reducing production costs. Protein is the most important and expensive nutrient used in ruminant diets. Using non-protein nitrogen (NPN) sources such as urea or its products can be considered a cheap alternative source in animal feeding. Iran is one of the most important urea-producing countries in the world; therefore, using urea or its slow-release products as a feed additive in animal nutrition can be beneficial. In the past years, various sources of slow-release urea have been produced and used in animal feeding. Biuret (heated urea) is one of the slowrelease urea compounds, and its production cost is lower than other slow-release urea sources. Compared to urea, it has less solubility in water and is converted to ammonia in the rumen at a much slower rate. It is also less toxic than urea and has a lower negative effect on feed palatability, so it can be used to a greater extent than urea in the diet of ruminants. Biuret is very safe and it can be included in the diet of animals in an amount of 20 times higher than the toxic dose of urea. Biuret usually contains 248.5% crude protein (39.8% nitrogen content), which is a little less than urea. On the other hand, increasing the daily feeding frequency is one of the management methods that may improve the productive performance of livestock, as well as the quantity and quality of the carcass. Increasing the feed frequency may improve nitrogen retention and reduce body fat. It is believed that increasing the frequency of daily feeding will keep the feed fresh, reduce the amount of feed waste, and improve livestock performance. Therefore, this study aimed to investigate the effect of NPN source, in high-protein diets, and feeding frequency on growth performance, rumen parameters, and the activity of rumen microbial enzymes of fattening lambs. Materials and methods: Twenty-eight male Lori-Bakhtiari fattening lambs (age: four to five months; live weight: 36.1±3 kg) were assessed for 60 days using a 2×2 factorial experiment in a completely randomized design with four treatments and seven replications. The experimental high-protein diets (16% of DM) contained urea or biuret, which were given to the lambs in the form of a total mixed ration two or three times a day. The lambs were kept in 1×1.5 m2 individual stalls. Nutrient intake, growth performance, and ruminal parameters [on day 45 of the experiment at fasting (before morning feeding), three, and six h after feeding] including pH, ammonia and volatile fatty acid concentrations, and microbial enzyme activity were measured. [ABSTRACT FROM AUTHOR]

Non-protein nitrogen (NPN) refers to nitrogen-containing compounds without a peptide chain structure. NPN can be converted into bacterial protein under the action of rumen microorganisms and is one of the protein feed resources in ruminant production. In recent years, with the change of animal varieties and diet structure, the rational use of NPN in ruminant production has been limited. The paper mainly reviewed the application principle of NPN and its effect on rumen environment, feed utilization, growth performance and blood biochemical indexes of ruminants, and put forward the existed problems, so as to provide reference for further application of NPN in ruminant production. [ABSTRACT FROM AUTHOR]

Introduction1: Lack of animal feed, especially with development of industrial methods of animal husbandry waste in many parts of the world, has led farmers and researchers to try identifying and using agricultural and livestock waste and new food sources for animal nutrition, including poultry manure and urea is mentioned in the diet of ruminants. Due to the fact that no research has been done on the effect of barley grain processing methods and non-protein nitrogen sources in the diet on rumen degradability, gas production and microbial protein synthesis in sheep, the present study was conducted. Materials and Methods: This experiment was conducted in a completely randomized design with seven treatments including a control treatment containing whole barley grain (without milling) and without urea and chicken manure, treatments 2, 3 and 4 containing processing method of milling, filling and pelleting with a certain level of urea, respectively. (1%) And treatments 5, 6 and 7 containing processing methods of milling, filling and pelleting with a certain level of poultry manure (12%) were performed on sheep. Each treatment consisted of 5 fattening lambs at the age of 3 months 24±1 which were kept individually in separate cages for 14 days of acclimatization period and 84 days of fattening period. In the second experiment, rumen degradability of dry matter, crude protein and NDF of experimental diets were measured using a nylon bag method with 3 fistulated male sheep that were fed in the maintenance level. Extent and rate of gas production were done based on Menk and Stingas. The NH3-N concentration was determined following the Broderick and Kang (1980) technique. Purine derivatives and was measured by the method of Chen and Gomes (1995). Rumen fluid was collected for 5 consecutive days in the end of each period and ruminal fermentation parameters containing pH and NH3-N and were determined. Urine of sheep was collected end of each period for 5 days and microbial protein synthesis was estimated by measuring purine base. Data were analyzed using SAS software version 9.9 (54) using GLM procedure. Results and Discussion: The apparent digestibility of dry matter and organic matter were significantly different, and the control treatment (whole barley grain without urea and poultry manure) had the highest apparent digestibility. Digestibility in non-fibrous carbohydrates was significantly different, so that treatment 5 (processing method of milling with poultry manure) had the highest apparent digestibility. Different parameters of degradability of dry matter, crude protein and insoluble fibers in neutral detergent of experimental treatments indicated significant differences between treatments (P<0.05). Barley grain processing with non-protein nitrogen sources caused a significant difference in the fast decomposing part, slow decomposing part and degradable part of dry matter, crude protein and insoluble fibers in the crude protein neutral detergent of experimental treatments. Effective degradability of dry matter, crude protein and insoluble fibers in neutral detergent at 2, 4 and 6% per hour passage rates had a significant difference between experimental treatments. The results showed that there was a significant difference between the experimental treatments in terms of gas production parameters and the amount of gas produced in 96 hours (P<0.05). There was a significant difference between experimental treatments in terms of digestibility of organic matter, amount of metabolizable energy and concentration of short-chain volatile fatty acids. The highest pH was assigned to treatment 7 (6.30) and the lowest pH was assigned to treatment 1 (6.10). Ammonia nitrogen had a significant difference in experimental treatments. The highest ammonia nitrogen was related to treatment 5 (11.45 mg/dL) and the lowest ammonia nitrogen was related to treatment 3 (10.38 mg/dL). The excretion rate of each of the purine derivatives (allantoin, uric acid, xanthine + hypoxanthine) and the total urinary excretion of purine derivatives and the amount of microbial protein synthesized in the rumen were affected by the test diets and the observed difference was significant (P<0.05). There was a significant difference in rumen pH in experimental treatments. The results showed that barley grain processing methods with non-protein nitrogen sources had a significant effect on rumen degradability, gas production, rumen parameters and microbial protein synthesis compared to the control group. Conclusion: In general, the use of urea (1%) and poultry manure (12%) with different methods of barley grain processing without negative effects on rumen degradability, rumen liquid parameters and gas production in terms of microbial protein synthesis can be useful. [ABSTRACT FROM AUTHOR]

Because the non‐protein nitrogen sources can be an option for a ruminant diet to replace true-protein sources, we hypothesized that using extruded urea in increasing levels by reducing soybean meal in the diet can maintain or improve the productive performance of beef cattle in a feedlot. It was aimed to evaluate the effects of extruded urea levels on the productive performance and carcass and meat characteristics of Nellore steers in feedlot. Twenty-four Nellore steers, with an average age of 22 months and an average initial weight of 333.5 kg, were used. A completely randomized design was used with four treatments: 50, 60, 70, and 80 g/100 kg BW of extruded urea. There was no effect of extruded urea levels on nutrient intake. The final weight and average daily gain were adjusted by a quadratic equation, with maximum estimated values of 479.18 kg and 1.02 kg/day with the inclusion of 59.71, 54.14, and 54.16 g/100 kg BW of extruded urea, respectively. There was no effect (P > 0.05) of extruded urea levels on hot carcass weight (233.3 kg), carcass yield (53.2%), ribeye area (72.7 cm2), and subcutaneous fat thickness (5.3 mm). Likewise, there was no effect (P > 0.05) of extruded urea levels on meat chemical composition, shear force (8.9 KgF), cooking losses (28.2%), pH (5.6), and meat color parameters. We recommended the use of 70 g/100 kg BW of extruded urea in the diet for finishing Nellore steers in confinement. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of O-carboxymethyl chitosan coating on microbiological, physiochemical, and water characteristics of Mongolian cheese during refrigerated storage. O-carboxymethyl chitosan coatings, particularly at 1.5%, improved cheese preservation by significantly inhibiting microbial growth, reducing changes in protein and non-protein nitrogen, and preserving pH and titratable acidity. For texture profile analysis (TPA), the hardness, gumminess, and chewiness in O-CMC treatments were significantly more stable than those in the control during storage. In addition, the relaxation component and image of nuclear magnetic resonance (NMR) were used to analyze the internal water mobility of the cheese during storage. Compared with other treatments, the 1.5% O-carboxymethyl chitosan coating had the best overall preserving effect during storage. O-carboxymethyl chitosan coating could be used in cheese preservation applications and could extend the shelf life of Mongolian cheese. The cheese coated with 1.5% O-carboxymethyl chitosan coating ranked the highest in acceptability at the end of the storage period. [ABSTRACT FROM AUTHOR]

This study investigated the effect of coated urea supplementation associated with monensin on rumen metabolism and fermentation, in cattle consuming a low-quality forage-based diet. Eight ruminally cannulated Nellore cows consuming Brachiaria brizantha cv. Marandu hay were randomly assessed to two 4 × 4 Latin square design, in a 2 × 4 factorial arrangement, with a factorial treatment arrangement with the factors: (i) urea source: (CON) no urea, (URE) common urea, (PCU) polymer-coated urea and (LCU) lipid-coated urea; (ii) monensin: (MON) addition of monensin in the diet; and (NM) no addition of monensin in the diet. Ruminal NH3-N concentration was affected by urea source and there was an interaction between time and the urea source. Rumen acetate molar concentration was lower, while rumen propionate was greater for URE compared to coated urea. The total tract apparent digestibility of crude protein (CP) and non-protein nitrogen (NPN) were greater for URE compared to coated urea treatments and for LCU compared to PCU. Animals fed URE had greater urea excretion compared to coated urea. In conclusion, coated urea generates a lower ammonia peak; however, both coated urea did not promote total nitrogen release. No synergy was observed with the combination of urea and monensin. [ABSTRACT FROM AUTHOR]

Unique stomach physiology allows ruminants to utilise any form of dietary nitrogen (N) as a protein source. Ruminant N requirements can be divided into N requirements for microbial fermentation and host requirements for amino acids. Ruminant diets often contain non-protein nitrogen (NPN) compounds, a group of components that are not proteins but can be converted to proteins by rumen microbes. Therefore, NPN compounds in ruminant diets serve as alternative sources of ammoniacal nitrogen (NH3-N), which is necessary for the synthesis of microbial protein (MCP) in the rumen. MCP is an important component of metabolizable protein for ruminants and, under certain production conditions, may be the only amino acid source for synthesis of tissues and products. In this manner, ruminants utilise NPN compounds without having enzymes for their degradation. The use of NPN compounds in ruminant nutrition allows for an increase in feed consumption and utilisation, as well as the substitution of protein supplements, which in turn leads to more cost-effective production. However, abrupt supplementation or excessive consumption of NPN could negatively affect MCP synthesis, feed digestion, and animal production. On the other hand, it may lead to animal poisoning and the release of large amounts of N into the environment. Knowledge of N metabolism in the rumen, as well as optimization of its utilisation, sets the conditions for the presumed beneficial effects of NPN compounds in ruminant diets, without adverse effects on animal health and the environment. Therefore, the aim of this study was to summarize the recent literature data on the metabolism and utilisation of NPN compounds in ruminants.

ABSTRACT The aim of this study was to evaluate the effects of replacing 50% of the true protein from soybean meal with extruded urea on the performance and carcass characteristics of lambs finished on pasture. Twenty lambs with initial weight of 29.9±6.2kg and 5 months of age, distributed in two treatments in blocks at random, were kept in pastures of Urochloa spp. Supplemented with 2% of body weight (BW). The treatments consisted of supplements containing soybean meal as the only true protein source (control), or extruded urea replacing 50% of soybean meal (NPN treatment). There was no effect of treatment on total supplement intake. There were differences in average daily gain (242.1 vs. 264.6g/day), slaughter weight (41.9 vs. 45.0kg) and carcass weight (18.9 vs. 20.1kg). There was no effect of the treatment on the final body condition score, hot carcass yield, carcass length, breast depth, subcutaneous fat thickness or rib eye area. The group of animals that received extruded urea showed superior carcass finishing characteristics (99.0% vs. 66.0%), maturity (22.0% vs. 0.0%), marbling (55.0% vs. 33.0%), meat texture (44.0% vs. 33.0%) and fat (66.0% vs. 22.0%). There were no significant effects on tenderness (7.5kg/f) or flesh color (L* = 33.2; a* = 16.2; b* = 8.3). There were no significant changes in the biochemical profile of the animals' blood during the experiment for both treatments. The replacement of 50% of protein from soybean meal by the extruded urea as NPN source in the supplement for lambs finished in Urochloa spp pastures provides better animal performance and qualitative characteristics of meat, without altering quantitative carcass characteristics.

The qualitative composition of commercial milk is a relevant issue of the food industry. The khainak, or yattle, is a hybrid between the yak and domestic cattle. The research objective was to study the seasonal protein composition of khainak milk from the Northern Kyrgyzstan highlands. The study featured samples of khainak milk obtained from farms located in the Issyk-Kul region at an altitude of 2840 m above sea level. Standard research methods included high pressure liq uid chromatography and capillary electrophoresis. Khainak milk has more protein than cow milk, and the mass fraction of protein in it is 3.91–4.39%. In this research, the mass fraction of protein in khainak milk obtained in spring, summer, and autumn exceeded that of cow milk by 0.54, 1.02, and 0.84%, respectively. The total nitrogen content correlated with the mass fraction of protein, i.e., it was at its highest in summer (0.689 ± 0.004%). The content of non-protein nitrogen remained almost the same (0.0489–0.0496%). Spring milk contained by 0.2% more whey protein than summer milk (0.94 ± 0.05%) and autumn milk (0.97 ± 0.05%). Summer milk demonstrated a 1% increase in casein proteins, compared to spring and autumn samples. The average β-lactoglobulin content was 2.35 mg·mL–1, while α-lactoalbumin was 2.12 mg·mL–1 of the total albumin fraction. In terms of amino acid composition, khainak milk was balanced except for tryptophan. In the warm season, the content of essential amino acids was higher than in the cold season, which corresponded to the changes in total protein co ntent. Khainak milk is richer in protein and some other components than cow milk, which makes it a valuable non-traditional dairy raw material for such protein products as cheese or cottage che ese, including their functional variants.

Background and Objectives: In some respects, Food processing may increase livestock performance. Today some methods of grain processing have been considered. On the other hand, the lack of animal feed, especially with the development of industrial methods of animal husbandry waste in many parts of the world, has led farmers and researchers to think about identifying and using agricultural and livestock waste and new food sources for animal nutrition, including poultry manure. And urea is mentioned in the diet of ruminants. Since no research has been done on the effect of barley grain processing methods and non-protein nitrogen sources in the diet on growth performance, nutrient digestibility, and carcass characteristics in Afshari breeding fattening lambs, the present study was conducted. Materials and Methods: This experiment was conducted in a completely randomized design with seven treatments, including a control treatment containing whole barley grain (without milling) and without urea and chicken manure. Treatments 2, 3 and 4 were processing methods of milling, filling, and pelleting, respectively, with a certain level of urea. (1%) And treatments 5, 6 and 7 were processing methods of milling, filling and pelleting, respectively, with a certain level of poultry manure (12%). Five Afshari lambs (24±1 kg, age of 3 months) were assigned to each of the treatments. Lambs were then kept individually in separate cages for 14 days as an adaptation period following 84 days of fattening period. Dry matter, ash, crude fiber, crude fat and crude protein were determined using the method (AOAC, 2000), Neutral detergent fiber and Acid detergent fiber based on the method of Van Soest et al (1991). At the end of the rearing period, three heads from each treatment were randomly slaughtered, then hot and cold carcass weights were measured as well as evaluation of its components. Results: experimental treatments. The apparent digestibility of dry matter and organic matter were significantly different, and the control treatment (whole barley grain without urea and poultry manure) had the highest apparent digestibility. Digestibility in non-fibrous carbohydrates was significantly different, therefore, treatment 5 (processing method of milling with poultry manure) had the highest apparent digestibility. Experimental treatments were significant on thigh weight, neck weight, tail weight, ventricular fat weight, carcass length, and half-carcass length. Conclusion: The results showed that processing methods of barley grain with sources of non-protein nitrogen had a significant effect on daily weight gain, dry matter consumption, feed conversion ratio, some organs of fattening lambs, digestibility of dry matter, and organic matter compared to the control group. Generally, it is possible to use barley grain processing with urea (1%) and poultry manure (12%) in the diet of fattening lambs without harmful effects on production parameters and fattening performance. [ABSTRACT FROM AUTHOR]

The aim was examine the effects of substituting the crude protein (CP) from soybean meal (SM) with the CP from urea on the intake, nutrient digestibility and feeding behaviour of feedlot lambs with buffel grass hay as the roughage source. Five uncastrated Dorper × Santa Inês mixed-breed lambs with an average initial weight of 17 ± 1.5 kg were evaluated in a 5 × 5 Latin square design. Treatments consisted of diets in which 0.0, 25.0%, 50.0%, 75.0% and 100% of the CP from SM were substituted by the CP from urea. Compared with diet without urea, dry matter (DM) intake and organic matter intake were similar to diet containing 25% of urea, whereas they were lower in the animals fed diets containing 50%, 75% and 100% of CP from urea. The digestibility coefficients, feeding behaviour, nitrogen (N) balance, N intake and N losses in faeces were not influenced. Urinary N losses differed, with the highest values in the animals fed diets in which 75% and 100% of SM was replaced. Up to 25% of the CP, which corresponds to 3.16% of DM from SM can be substituted by CP from urea in diets containing buffel grass hay for feedlot lambs. [ABSTRACT FROM AUTHOR]

As a large farming country, China has a perennial shortage of protein feeds, and needs to find ways to replace protein feeds in reduced quantities in animal production. Non-protein nitrogen such as urea is relatively inexpensive and can replace part of protein feed in ruminant production, providing a nitrogen source for protein synthesis by rumen microorganisms and reducing production costs. In recent years, there has been increasing research and application of liquid feeds, but less research has been done in ruminant production. The article summarizes the principles of non-protein nitrogen utilization by ruminants, the application of non-protein nitrogen in ruminant production, and provides a reference for the development and utilization on the production of non-protein nitrogen liquid concentrate feeds for ruminants. [ABSTRACT FROM AUTHOR]

Commercial concentrates are the main supplemental feeds used by farmers in Trinidad and Tobago (T&T) to off-set nutritional or herbage deficit of forage-based diets for ruminants. While the crude protein (CP) contents of these commercial feeds are known, the quality of the protein for different classes of ruminants is unknown. Therefore, this study examined the nitrogen and crude protein fractions and ruminal CP degradability of the most popular concentrate feeds used for feeding ruminants in T&T. Eight commercial concentrate feeds from two leading manufacturers were collected over a 5-month period. These feeds comprised three dairy rations (DR-1, DR-2 and DR-3), two small ruminant rations (SR-1 and SR-2), two all-purpose rations (APR-1 and APR-2), and a dry cow ration (DCR). The eight feeds were evaluated for total nitrogen (N), buffer soluble N (BSN), buffer insoluble N (BISN), non-protein N (NPN), neutral detergent insoluble N (NDIN), acid detergent insoluble N (ADIN), protein fractions A, B1, B 2, B3, C, true protein, rumen degradable protein (RDP), rumen undegradable protein (RUP) and in vitro ruminal crude protein degradability. CP contents were highest in DR-2 (206 g/kg DM) and lowest in SR-2 (139 g/kg DM). APR-2 had the highest BSN (336 g/kg DM) and NPN (189 g/kg DM) and the lowest ADIN (21.1 g/kg DM) and BISN (664 g/kg DM) contents. Crude protein fraction B1 was lowest and B2 was highest in DR-2. Feeds with the highest and lowest RUP contents were DR-2 (150 g/kg DM) and SR-1 (82.6 g/kg DM), respectively. Highest 3-hour in vitro ruminal CP degradability was observed in APR-2. It was concluded that protein quality of commercial ruminant feeds in T&T varies with feed type, with DR-2 and SR-2 having the highest RUP contents to support the lactating dairy cow and fattening lamb, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT: Urea is an organic compound characterized as a white, solid, and hygroscopic substance. It is recognized as a source of non-protein nitrogen (NPN) and is widely used as a partial replacement for protein in cattle diets due to the ability of the ruminal microbiota to convert it into microbial protein. Despite the advantages of using urea, it also has limitations, particularly the proximity between metabolizable and toxic or fatal doses. Furthermore, for safe use, a period of adaptation is necessary for the animals. Poisoning is characterized by rapid and generally fatal development, which is frequent in non-adapted animals but can also occur in those with previous adaptations. The aim of this study was to characterize the clinical, epidemiological, and pathological aspects of urea poisoning through a brief review and a retrospective study. In addition, interviews were conducted with veterinarians who frequently send diagnostic material to the Laboratory of Anatomic Pathology of the “Faculdade de Medicina Veterinária e Zootecnia” (LAP-FAMEZ) to assess their perception of the outbreaks of urea poisoning. The objective was to obtain a comparative scenario between published cases and those received by the laboratory while considering the real situation of this condition in the field. During this retrospective study, only four outbreaks were investigated; in one, the diagnosis was possible through experimental reproduction. Of 35 interviewees, 88.9% said they had seen more than one case compatible with urea poisoning, but 87.5% did not perform a necropsy and/or send material to confirm the diagnosis. The results show that the reality of urea poisoning may be very distant from that reported in previous studies due to the difficulty often observed in the diagnostic approach, so we developed a flowchart aiming to provide a useful guide for field veterinarians.

The demands of quality and choice in the dairy industry require analysis of extended performance. Ancient milk protein measuring devices take a long time and provide slow and inaccurate results. This work is part of the reliable analysis of cow’s milk proteins and defines the laws linking the two parameters, total nitrogen (NT) and protein nitrogen (NP). We are studying to prove a fast and effective method for measuring the non-protein nitrogen (NPN) composition of milk that allows the direct calculation of NP from the NT value, whose objective is to adapt the calibration of the Milko Scan FT2 cow’s milk protein analysis since NPN has a direct impact on protein analysis, payment of milk, and on the manufacture of milk products. The study showed that there is a compatibility between these two parameters and gave an idea of the percentage (5.9%) of NPN in milk. New analytical solutions such as the latest generation of the Kjeldahl K-375/376 and the new Milko Scan FT2 meet these needs. Data processing is done using XLSTAT, which is free statistical analysis software.

The aim of this study was to evaluate the flint corn processing method (CPM) and urea source for finishing Nellore bulls fed corn-based diets. In this study, 80 Nellore bulls [initial body weight (BW) = 388 ± 45.7 kg] were allocated into 28 pens (7 pens/ treatment; 6 pens with 3 bulls + 1 pen with 2 bulls). A completely randomized design with a 2 × 2 factorial arrangement of treatments was used to test two CPMs: dry ground corn (DGC) and reconstituted and ensiled corn (REC), and two US: feed-grade urea (FGU) and post-ruminal release urea (PRU). Dietary inclusion (% DM) of flint corn (vitreousness = 86.0%) was 61.3% (DGC or REC), and urea source addition was 0.5% as non-protein nitrogen (NPN; as FGU or PRU). The PRU source (Trouw Nutrition, Netherlands) contained 82% urea on a DM basis. In an in vitro assay, 27% of this urea was released into the rumen. Experimental period lasted 100 d (with 14 d of adaptation). Fecal samples from each bull were collected in two periods of three consecutive days (d 44 to 46 and 94 to 96) at different time (0600, 1200, and 1800 h). Samples were composited by pen and analyzed for fecal starch (FS) and indigestible NDF as markers for fecal excretion. At the end of the experiment, bulls were slaughtered and the jejunum and pancreas were sampled from one bull per pen. Interaction effects were not found (P ≥ 0.31) for any feedlot growth performance variables (Table 1). Final BW, average daily gain, and feed efficiency (gain to feed; G:F) were greater for bulls fed REC and PRU than for those fed DGC and FGU (P < 0.02), respectively. As a result, observed dietary net energy (NE) for maintenance and BW gain were about 7.0% and 9.0% greater for bulls fed REC diets, and 4.3% and 5.6% greater for bulls fed PRU diets, respectively. Bulls fed DGC had 2.2 times greater FS compared with bulls fed REC, resulting in lower fecal pH and total tract starch digestibility (TSD) for bulls fed DGC compared with those fed REC (P < 0.01). Interestingly, a similar trend was observed in bulls fed PRU compared with those fed diets with FGU (P < 0.06). Jejunal gene expression of SLC5A1 was not affected by treatments (P > 0.14). Nevertheless, bulls fed diets with PRU presented greater jejunal α-amylase activity (P = 0.02). Pancreatic α-amylase activity was less when bulls were fed DGC + PRU diet. In conclusion, REC markedly improved TSD and growth performance compared with DGC. Additionally, independent of CPM, PRU inclusion as NPN source increased G:F and dietary NE concentration due to the positive effects on jejunal amylase activity and TSD. [ABSTRACT FROM AUTHOR]

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for the renewal of the authorisation of urea as nutritional feed additive. The additive is authorised for use in ruminants with functional rumen (3d1). The applicant provided evidence that the additive currently in the market complies with the existing conditions of authorisation and the production process has not been substantially modified. The FEEDAP Panel considers that there is no evidence to revise the conclusions reached in the previous assessment for the target species, consumer and for the environment when used as a source of non‐protein nitrogen under current conditions of use, in ruminants with functional rumen. In the absence of new data, the FEEDAP Panel is not in the position to conclude on the user safety. The Panel retains that previously made conclusion on the efficacy remains valid. [ABSTRACT FROM AUTHOR]

Simple Summary: A fundamental step to meet the growing demand for animal protein and address environmental management is to identify and enhance the production of grazing cattle, that is, to improve the efficiency of use by animals. Efforts to improve nitrogen use efficiency and fiber digestion have focused on improving fiber quality, mainly in low-quality forages, with a post-ruminal delivery source. This approach has aimed to maximize microbial synthesis and reduce losses by excretion. The objective of this study was to evaluate the effect of post-ruminal urea, compared to conventional urea, on the metabolism and performance of Nellore cattle reared on pasture during the dry period. The use of a post-ruminal source presents a delay in relation to the rumen in the delivery of nitrogen through recycling. Therefore, the delivery of ammonia occurs more slowly and steadily throughout the day, which would result in a delay. Our findings highlight differences only in crude protein intake, supplement, and protein digestibility for post-ruminal urea production. The objective of this study was to evaluate the effect of the use of post-ruminal urea on performance, nitrogen metabolism and the ruminal environment of Nellore cattle reared on pasture during the dry season. In experiment 1 (Exp. 1), nine ruminal-cannulated Nellore steers, 30 ± 2 months old (651 ± 45 kg body weight (BW)), were allotted to a 3 × 3 Latin triple square. In experiment 2 (Exp. 2), 84 Nellore bulls, 18 ± 3 months old (315 ± 84 kg BW), were distributed in complete randomized blocks, by initial BW. Protein supplements were supplied daily, in the amount of 2 g/kg BW, and consisted of either CONT: protein + conventional urea (50% CP), PRU: protein + post ruminal urea (50% CP) and U + PRU: protein + urea conventional + post-ruminal urea (70% CP). The paddocks were composed of Urochloa brizantha cv. Marandu grass. In Exp. 1, there was no treatment effect for DM, OM, NDF, forage intake, and CP, but there was a higher intake for PRU (p < 0.005) and a higher digestibility for U+ PRU (p = 0.001). There was no effect on ruminal pH or NH3-N concentration (p ≥ 0.232), but there was an interaction between treatment and time for them (p < 0.039). Furthermore, there was a treatment effect on the total SCFA concentration, with CONT being higher than the others. A difference in the acetate:propionate ratio was found (p < 0.027), with a greater relationship for PRU and U + PRU. A treatment effect (p = 0.049) was found for the propionate proportion, with a higher proportion in the CONT. Nitrogen intake was consequently lower for the CONT and higher urinary excretion for the U + PRU (p = 0.002). Animals supplemented with CONT showed a tendency to have more Bacteria and fewer Archaea (p = 0.086). In Exp. 2, there was a treatment effect for the disappearance rate of the supplement (p < 0.001). Intake was faster for PRU and CONT, but performance was not affected by PRU (p = 0.311). The use of post-ruminal urea alters the microbial population, but does not affect performance. Therefore, supplementation with post-ruminal urea presented similar results compared to conventional urea. Ruminal and blood parameters and animal performance were not influenced by treatments. [ABSTRACT FROM AUTHOR]

Non-protein nitrogen (NPN) is abundant in stingray (Himantura signifier) muscle, which also has in vitro antioxidant activity. In this study, NPN from stingray muscle was further investigated for its antioxidant properties in lecithin liposome and oxymyoglobin model systems to validate its protective impact against lipid and myoglobin oxidations during storage for 120 min at various temperatures (4, 25, and 60 °C). NPN solution (10 ppm nitrogen) was added to the lecithin liposome system at different concentrations (0, 0.5, 1, 5, and 10% (v/v)) to investigate its effects on lipid stability by measuring the conjugated diene (CD), peroxide value (PV), and thiobarbituric acid reactive substances (TBARS) contents. In the oxymyoglobin system, NPN solution (10 ppm nitrogen) was also added at different concentrations (0, 0.5, 1, 5, and 10% (v/v)) to the oxymyoglobin solution in order to examine its effect on the stability of myoglobin by determining the contents of oxymyoglobin, metmyoglobin, and protein carbonyl. According to the findings, in all NPN concentrations, the system incubated at 4 °C had the lowest levels of lipid oxidation as measured by CD, PV, and TBARS values, and the lowest levels of myoglobin oxidation. At all incubating temperatures, the oxymyoglobin and lipid oxidation of all model systems tended to rise with the lengthening of the incubation duration. With the addition of 5% NPN, however, the lowest CD, PV, TBARS, oxymyoglobin oxidation, metmyoglobin formation, and protein carbonyl content were all observable, and the remarkable result was discovered during incubation at 4 °C. The results indicate that stingray NPN, especially at 5%, can be used to delay lipid and myoglobin oxidation, particularly at 4 °C. In order to prolong the shelf life of products with dark-fleshed fish and red meat, stingray NPN might be used as an alternative antioxidant to delay the oxidation of lipid and myoglobin during cold chain storage. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central European Agriculture is the property of Journal of Central European Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for the renewal of the authorisation of urea as nutritional feed additive. The additive is authorised for use in ruminants with functional rumen (3d1). The applicant provided evidence that the additive currently in the market complies with the existing conditions of authorisation and the production process has not been substantially modified. The FEEDAP Panel considers that there is no evidence to revise the conclusions reached in the previous assessment for the target species, consumer and for the environment when used as a source of non‐protein nitrogen under current conditions of use, in ruminants with functional rumen. In the absence of new data, the FEEDAP Panel is not in the position to conclude on the user safety. The Panel retains that previously made conclusion on the efficacy remains valid.

Introduction. The giant squid (Dosidicus gigas) is a species of great abundance and considered as potential resource to meet the demand for protein in Peru. Giant squid meal represents an alternative to traditional proteins which can be used in food fortification. Objective. To optimize the extraction process and identification of soluble protein from giant squid meal (GSM). Materials and methods. This study was conducted at the Universidad Nacional Agraria La Molina, Lima, Peru, between 2018 and 2019. To obtain the highest yield of soluble protein (Ŷ) extracted, an alkaline extraction method using NaOH followed by acid precipitation at pH 4.5 was applied. Surface response methodology was used to determine the optimal parameters for protein extraction such as temperature, concentration of NaCl, time, and the ratio GSM: solvent. A 1D and 2D electrophoresis study was carried out to find the distribution of molecular weights and to identify the main proteins of GSM. Results. Values for optimal response were the concentration of NaCl 0 M, an extraction time of 35 min, the ratio GSM: solvent of 1:31.72, and a temperature at 71.9 ºC. The molecular weights of the proteins detected were in the range of 6.5 and 38.37 kDa, which would correspond to tropomyosins, troponins, and myosin light chain residues. Conclusions. This study allowed to optimize the extraction parameters and to identify soluble proteins corresponding to the sarcoplasmic fraction of the giant squid meal (GSM), which could be used in the food industry.

Simple Summary: Protein is a crucial nutrient for improving performance and fiber utilization by grazing ruminants. The use of non-protein sources can be used to improve the intake and digestibility of poor-quality forages, since rumen microbes can use NPN to synthesize amino acids. Urea supplementation has become common for cattle. However, urea shows a rapid hydrolysis in the rumen, which can lead to excess ammonia and can impair animal performance and risk intoxication. Supplementation with post-ruminal available urea can prevent ammonia accumulation and can be an alternative source of nitrogen for grazing cattle. The objective of this study was to evaluate the effects of post-ruminal urea supplementation in different types of supplement formulation for Nellore bulls in the growing phase during the seasonal period. Performance and rumen environmental parameters were also evaluated. Our results emphasize that replacing soybean meal as a source of true protein with non-protein nitrogen resulted in reduced performance, and that conventional urea and post-ruminal urea have similar effects on animal performance and rumen metabolism. The objective was to evaluate the effects of urea with post-ruminal absorption in the supplementation of growing Nellore cattle reared on pasture during a seasonal period. For the study, two experiments were conducted. In experiment 1, rumen and blood parameters were evaluated using eight rumen-cannulated Nellore bulls with initial body weight (BW) of 763 ± 44 kg, distributed in a double Latin square 4 × 4. In experiment 2, 120 Nellore steers with initial BW of 380 ± 35 kg were used for performance evaluation, distributed in a randomized block design (blocking factor or initial BW). The evaluated treatments were 1: (TP-U) (control) = supplement with 24% crude protein (CP) containing urea as a source of non-protein nitrogen (NPN; 3%) and soybean meal, 2: (TP-PRU) = 24% CP supplement containing post-ruminal urea (PRU; 3.6%) and soybean meal; 3: (NPN-U-PRU) = 24% CP supplement containing urea + post-ruminal urea (U = 3% and PRU = 3.9%), without soybean meal; 4: (NPN-PRU) = supplement with 24% CP containing post-ruminal urea (7.5%), without soybean meal. The supplement was offered at 3 g/kg BW per animal, daily, once a day. All animals were kept on Urochloa brizantha cv. Marandu pasture. Statistical analyses were performed using the SAS PROC MIXED, and the data were evaluated by the following contrasts: C1 = TP-U/TP-PRU vs. NPN-U-PRU/NPN-PRU (Soybean meal replacement by NPN); C2 = TP-U vs. TP-PRU (conventional urea vs. post-immune urea); C3 = NPN-U-PRU vs. NPN-PRU (low and high post-ruminal urea-PRU level). The digestibility of dry matter, organic matter, and NDF was lower when soybean meal was replaced by non-protein nitrogen, also being different between the levels of post-ruminal urea used in the supplement. Ruminal pH was different when soybean meal was replaced by NPN (p = 0.003). Total concentration of short-chain fatty acids, concentrations of isobutyrate (p = 0.003), valerate (p = 0.001), and isovalerate (p = 0.001) were different, and blood urea was different when soybean meal was replaced by NPN (p = 0.006). Simpson's diversity index was higher in the rumen of animals supplemented with TP-U than in those supplemented with TP-PRU (p = 0.05). A total of 27 phyla, 234 families, and 488 genera were identified. Nitrospirota and Gemmatimonadota phyla were detected just in the rumen of steers supplemented with TP-PRU. The performance (final BW, weight gain and gain per area) of the animals was different, being higher (p = 0.04) in animals supplemented with soybean meal, compared to NPN. The removal of soybean meal from the supplement and its replacement with either conventional urea plus post-ruminal urea or only post-ruminal urea compromises the performance of the animals. The lower the post-ruminal urea inclusion level, the lower the apparent digestibility of dry matter, organic matter, and NDF, when compared to animals supplemented with higher levels. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A 2 × 2 factorial arrangement of treatments was used to investigate the interactive effects of dietary macronutrient composition [high-starch, low-fat, low-fiber (HsLFF) than low-starch, high-fat, high-fiber (LsHFF)] and N source [soybean meal (SBM) or partially replaced by slow-release urea (SRU)] on lactation performance, rumen fermentation, N utilization efficiency, nutrient digestibility, blood metabolites, and feeding behavior in cows. A replicated 4 × 4 Latin square design was used involving 12 multiparous Holstein cows (milk yield of 40.5 ± 5.6 kg/d, BW of 590 ± 20 kg; 81 ± 12 d in milk). The HsLFF diet contained 300 g/kg starch, 31.3 g/kg fat, and 301 g/kg NDF, without straw or additional fat. In contrast, the LsHFF diet contained 195.5 g/kg starch, 60.8 g/kg fat, and 367.5 g/kg NDF, enriched with wheat straw (100 g/kg), and additional fat (34 g/kg). The diets were formulated to be iso-nitrogenous and isocaloric. Cows fed the HsLFF diet had greater DM intake, digestibility of DM and CP, milk yield and milk protein %, but lower intakes of NDF, and physically effective NDF, and milk fat % than cows fed the LsHFF diet. Replacing SBM with SRU significantly increased milk solids yield without affecting other lactation performance or BW. Cows fed the LsHFF diet had higher ruminal pH and branched-chain VFA proportions but lower total VFA concentrations compared with the HsLFF diet, while those on the LsHFF-SRU diet had the highest ruminal ammonia levels. Compared with the HsLFF diet, cows fed LsHFF had lower NE intake, milk energy output and energy requirement for maintenance, although energy balances were similar among groups. The HsLFF diet improved N utilization, resulting in higher N content in milk and lower N excretion in feces. Blood metabolite studies showed significant interactions between the main factors, particularly for blood glucose and creatinine, with the lowest levels in cows fed the LsHFF-SRU and LsHFF-SBM diets. In addition, alanine aminotransferase levels were higher in cows fed the LsHFF diet than in cows fed the HsLFF diet. This could indicate early-stage liver stress due to the metabolic imbalance caused by a high-fat, low-starch diet, which can alter energy metabolism. Cows on the HsLFF-SRU diet had the highest glucose levels, indicating possible changes in carbohydrate metabolism or a higher metabolic rate. The concentration of BUN increased steadily after feeding in the LsHFF diet and peaked after 4 h in the LsHFF-SRU diet, with no difference between N sources in the HsLFF diet. Partial replacement of SRU with SBM had no effect on BUN. The interaction between the main factors had a significant effect on MUN content, which was highest in LsHFF-SRU and lowest in HsLFF-SRU, with no difference between the N sources in the HsLFF diets. Overall, while diets with reduced starch and increased fiber and fat compromised lactation performance, partially substituting SRU with SBM helped maintain milk production and milk nitrogen efficiency. However, the LsHFF-SRU diet was less efficient in N utilization, as shown by higher levels of ruminal ammonia, BUN and MUN., (©, The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The objective was to evaluate the effect of replacing common urea with protected urea in the supplement on the nutrient intake and digestibility and metabolic profile of sheep. Five adult sheep, with an average age of 4 years and an initial average body weight of 50 ± 4.03 kg, were used. The diet consisted of sorghum silage, supplemented with a multiple mixture of corn bran, soybean meal, white salt, mineral salt, common urea (CU) or protected urea (PU). The experimental design was a 5x5 Latin square. Treatments consisted of: control or 100% CU, 75% CU and 25% PU, 50% CU and 50% PU, 25% CU and 75% PU and 100% PU. Collections and analysis of feed, feces, urine and blood were carried out to assess intake, digestibility and blood metabolites. Analysis of variance and SNK test were applied considering 5% significance. Nonparametric data were analyzed by Kruskal-Wallis at a significance level of 5%. The replacement of common urea with protected urea did not (P> 0.05) alter the intake of dry matter, crude protein and water, and the dry matter digestibility. The production of urine and feces, and the density of urine also did not (P> 0.05) show statistical difference with the replacement of common urea with protected urea. As for protein and energy metabolites, only glycemia showed variation (P

The objective of this study was to evaluate the effect of O-carboxymethyl chitosan coating on microbiological, physiochemical, and water characteristics of Mongolian cheese during refrigerated storage. O-carboxymethyl chitosan coatings, particularly at 1.5%, improved cheese preservation by significantly inhibiting microbial growth, reducing changes in protein and non-protein nitrogen, and preserving pH and titratable acidity. For texture profile analysis (TPA), the hardness, gumminess, and chewiness in O-CMC treatments were significantly more stable than those in the control during storage. In addition, the relaxation component and image of nuclear magnetic resonance (NMR) were used to analyze the internal water mobility of the cheese during storage. Compared with other treatments, the 1.5% O-carboxymethyl chitosan coating had the best overall preserving effect during storage. O-carboxymethyl chitosan coating could be used in cheese preservation applications and could extend the shelf life of Mongolian cheese. The cheese coated with 1.5% O-carboxymethyl chitosan coating ranked the highest in acceptability at the end of the storage period.

Milk FAs were quantified by comparing the retention time of FA methyl esters from standards (18919-1 Sigma Aldrich, St. Louis, MO, USA) and milk samples. Despite the unchanged milk SCC in the present study, milk oxidative stress can also be associated with subclinical mastitis, as observed by Silanikove et al. [[43]], who also suggested that milk from dairy goats was less susceptible to nitrosative stress than milk from dairy cows because of its increased TAC. Table 4 Effects of calcium-ammonium nitrate (CAN) fed to lactating dairy goats on milk fatty acid (FA) profile. Keywords: antioxidant capacity; feed additive; hydrogen sink; nitrite; non-protein nitrogen EN antioxidant capacity feed additive hydrogen sink nitrite non-protein nitrogen N.PAG N.PAG 14 04/26/22 20220415 NES 220415 1. [Extracted from the article]

Here, the effects of non-protein nitrogen sources on fermentation parameters and microbial diversity were explored using three fistula goats as rumen fluid donors. The experiments involved six fermenters in a replicated 3 × 3 Latin square design with three dietary non-protein sources [ammonium chloride (A), biuret (B), and glutamine (G)] as treatment factors. A dual-flow continuous culture fermentation system was used. Microbial protein content in group B was significantly lower than that in the other two groups (P < 0.05). Ammonia nitrogen concentration significantly differed among the three groups (P < 0.01), following the order of G > A > B group. The acetate-to-propionate ratio in group G was significantly lower than that in the other two groups (P < 0.01). At the phylum level, the relative abundances of Cyanobacteria, Elusimicrobia, and Armatimonadetes were the highest in group G, being significantly higher than those in group B (P < 0.05). At the genus level, the relative abundance of Ruminococcus_1 was significantly higher in group A than in group B (P < 0.05). Overall, glutamine shifted the fermentation pathway from acetate to propionate, and the lower microbial crude protein content and relative abundances of the major fiber-degrading bacteria Ruminococcus_1 and protein-degrading bacteria Prevotellaceae_UCG-001 in group B indicate that biuret is not suitable as a dietary non-protein nitrogen source.

Illegal adulteration of melamine in animal feed and food has been widely studied. However, the risk of using substitute non-protein nitrogen substances still exists. In this study, we developed the 13C NMR method for the detection of non-protein nitrogen substance adulteration in animal feed. Three compounds, i.e., urea, melamine, and biuret, were used for method development. We found that the chemical shifts of the characteristic peaks in the carbon spectra of high-nitrogen adulterants were all between 150 and 170 ppm, whereas the chemical shifts of real protein peptide bonds (-CO–NH-) were between 170 and 180 ppm, demonstrating a good distinction between non-protein nitrogen and authentic protein. The method for analyzing melamine, urea, and biuret was validated. The R2 values were all above 0.99 within the calibration range of 0.05–2% (w/w). The limits of quantification of urea, melamine, and biuret were 0.0120%, 0.0660%, and 0.0806%, respectively. This method involves simple sample pretreatment and rapid detection while also providing high accuracy. All the sample information obtained by NMR detection does not require strict impurity removal. Compared with a previously reported 1H NMR method, the developed 13C NMR method does not require strict moisture removal to avoid active hydrogen exchange, and the interfering peak overlap is mitigated. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of the use of post-ruminal urea on performance, nitrogen metabolism and the ruminal environment of Nellore cattle reared on pasture during the dry season. In experiment 1 (Exp. 1), nine ruminal-cannulated Nellore steers, 30 ± 2 months old (651 ± 45 kg body weight (BW)), were allotted to a 3 × 3 Latin triple square. In experiment 2 (Exp. 2), 84 Nellore bulls, 18 ± 3 months old (315 ± 84 kg BW), were distributed in complete randomized blocks, by initial BW. Protein supplements were supplied daily, in the amount of 2 g/kg BW, and consisted of either CONT: protein + conventional urea (50% CP), PRU: protein + post ruminal urea (50% CP) and U + PRU: protein + urea conventional + post-ruminal urea (70% CP). The paddocks were composed of Urochloa brizantha cv. Marandu grass. In Exp. 1, there was no treatment effect for DM, OM, NDF, forage intake, and CP, but there was a higher intake for PRU (p < 0.005) and a higher digestibility for U+ PRU (p = 0.001). There was no effect on ruminal pH or NH3-N concentration (p ≥ 0.232), but there was an interaction between treatment and time for them (p < 0.039). Furthermore, there was a treatment effect on the total SCFA concentration, with CONT being higher than the others. A difference in the acetate:propionate ratio was found (p < 0.027), with a greater relationship for PRU and U + PRU. A treatment effect (p = 0.049) was found for the propionate proportion, with a higher proportion in the CONT. Nitrogen intake was consequently lower for the CONT and higher urinary excretion for the U + PRU (p = 0.002). Animals supplemented with CONT showed a tendency to have more Bacteria and fewer Archaea (p = 0.086). In Exp. 2, there was a treatment effect for the disappearance rate of the supplement (p < 0.001). Intake was faster for PRU and CONT, but performance was not affected by PRU (p = 0.311). The use of post-ruminal urea alters the microbial population, but does not affect performance. Therefore, supplementation with post-ruminal urea presented similar results compared to conventional urea. Ruminal and blood parameters and animal performance were not influenced by treatments.

Non-protein nitrogen (NPN) is abundant in stingray (Himantura signifier) muscle, which also has in vitro antioxidant activity. In this study, NPN from stingray muscle was further investigated for its antioxidant properties in lecithin liposome and oxymyoglobin model systems to validate its protective impact against lipid and myoglobin oxidations during storage for 120 min at various temperatures (4, 25, and 60 °C). NPN solution (10 ppm nitrogen) was added to the lecithin liposome system at different concentrations (0, 0.5, 1, 5, and 10% (v/v)) to investigate its effects on lipid stability by measuring the conjugated diene (CD), peroxide value (PV), and thiobarbituric acid reactive substances (TBARS) contents. In the oxymyoglobin system, NPN solution (10 ppm nitrogen) was also added at different concentrations (0, 0.5, 1, 5, and 10% (v/v)) to the oxymyoglobin solution in order to examine its effect on the stability of myoglobin by determining the contents of oxymyoglobin, metmyoglobin, and protein carbonyl. According to the findings, in all NPN concentrations, the system incubated at 4 °C had the lowest levels of lipid oxidation as measured by CD, PV, and TBARS values, and the lowest levels of myoglobin oxidation. At all incubating temperatures, the oxymyoglobin and lipid oxidation of all model systems tended to rise with the lengthening of the incubation duration. With the addition of 5% NPN, however, the lowest CD, PV, TBARS, oxymyoglobin oxidation, metmyoglobin formation, and protein carbonyl content were all observable, and the remarkable result was discovered during incubation at 4 °C. The results indicate that stingray NPN, especially at 5%, can be used to delay lipid and myoglobin oxidation, particularly at 4 °C. In order to prolong the shelf life of products with dark-fleshed fish and red meat, stingray NPN might be used as an alternative antioxidant to delay the oxidation of lipid and myoglobin during cold chain storage.

We expected mitigation of the hypophagic effects of urea (U) with a coated urea (CU) product that aimed to partially shift urea supply to the post-ruminal gastrointestinal tract. Ruminal release and post-ruminal digestibility of CU was evaluated in vitro, followed by a randomised complete block experiment (54 Holstein-Friesian cows; 177 ± 72 days in milk). Soybean meal (SBM) was partially (PR) or fully (FR) replaced on an isonitrogenous basis by beet pulp and U or CU. Urea sources were included at 12 (U-PR, CU-PR) and 19 (U-FR, CU-FR) g/kg dietary dry matter (DM). Hypophagic effects were similar for U-PR and CU-PR (-11% vs. -7%), and for U-FR and CU-FR (-13% vs. -12%) compared with SBM (average 25.8 kg DM intake/d). Compared with SBM, U-PR and CU-PR reduced yields of milk (-8%) and protein (-12%), U-PR reduced yield of fat (-9%) and fat- and protein-corrected-milk (FPCM; -9%), and CU-PR tended to reduce FPCM yield (-5%). Compared with SBM, U-FR and CU-FR respectively reduced yields of milk (-21%, -22%), protein (-25%, -26%), fat (both -14%), lactose (-20%, -21%), and FPCM (-17%, -19%), and lowered N (-15%, -12%) and feed (-8%, trend, -9%) efficiency. Human-edible protein efficiency approximately doubled with U-PR and CU-PR and approximately tripled with U-FR and CU-FR compared with SBM. Milk composition and plasma urea concentration were similar between U and CU, except for a trend for a greater plasma urea concentration with U-PR compared with CU-PR. Dry matter intake patterns differed for CU-PR compared with U-PR and for CU-FR compared with U-FR, suggesting effects of urea release rate or location on feeding behaviour. Overall, replacing SBM with U or CU reduced DM intake and milk production and affected nutrient efficiencies. Coated urea influenced DM intake pattern but did not affect total DM intake or milk production compared with U., (© 2024 The Author(s). Journal of Animal Physiology and Animal Nutrition published by Wiley‐VCH GmbH.)

Background and Aims: Nitrogen (N) distribution in plants is intricately linked to key physiological functions, including respiration, photosynthesis, structural development, and nitrogen storage. However, the specific effects of different N morphologies on N accumulation and plant growth are poorly understood. Our research specifically focused on determining how different N morphologies affect N absorption and biomass accumulation., Methods: This study elucidated the impact of different application rates (CK: 0 g N/plant; T1: 4 g N/plant; T2: 8 g N/plant) of N fertilizer on N and biomass accumulation in tobacco cultivars Hongda and K326 at different growth stages., Results: Our findings emphasize the critical role of N distribution in various plant parts, including leaves, stems, and roots, in determining the complex mechanisms of N and biomass accumulation in tobacco. We found that in relation to total N, a greater ratio of water-soluble N ( N w ) in leaves facilitated N accumulation in leaves. In contrast, an increased ratio of SDS (detergent)-insoluble N ( N in-SDS ) in leaves and non-protein N ( N np ) in roots hindered this increase. Additionally, our results indicate that a greater proportion of N np in leaves has a negative impact on biomass accumulation in leaves. Furthermore, elevated levels of N in-SDS , N w , and N np in roots, and N np in leaves adversely affected biomass accumulation in tobacco leaves. The Hongda cultivar exhibited greater biomass and N accumulation abilities as compared to K326., Conclusions: Our findings highlight the significant role of distribution of N morphologies on plant growth, as well as N and biomass accumulation in tobacco plants. Understanding N distribution allows farmers to optimize N application, minimizing environmental losses and maximizing yield for specific cultivars. These insights advance sustainable agriculture by promoting efficient resource use and reducing environmental impact., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Li, Jiang, Ahmed, Yang, Yang, Zhang, Mei, Alharbi, Shan, Guo and Zhao.)

The objective was to evaluate the effects of urea with post-ruminal absorption in the supplementation of growing Nellore cattle reared on pasture during a seasonal period. For the study, two experiments were conducted. In experiment 1, rumen and blood parameters were evaluated using eight rumen-cannulated Nellore bulls with initial body weight (BW) of 763 ± 44 kg, distributed in a double Latin square 4 × 4. In experiment 2, 120 Nellore steers with initial BW of 380 ± 35 kg were used for performance evaluation, distributed in a randomized block design (blocking factor or initial BW). The evaluated treatments were 1: (TP-U) (control) = supplement with 24% crude protein (CP) containing urea as a source of non-protein nitrogen (NPN; 3%) and soybean meal, 2: (TP-PRU) = 24% CP supplement containing post-ruminal urea (PRU; 3.6%) and soybean meal; 3: (NPN-U-PRU) = 24% CP supplement containing urea + post-ruminal urea (U = 3% and PRU = 3.9%), without soybean meal; 4: (NPN-PRU) = supplement with 24% CP containing post-ruminal urea (7.5%), without soybean meal. The supplement was offered at 3 g/kg BW per animal, daily, once a day. All animals were kept on Urochloa brizantha cv. Marandu pasture. Statistical analyses were performed using the SAS PROC MIXED, and the data were evaluated by the following contrasts: C1 = TP-U/TP-PRU vs. NPN-U-PRU/NPN-PRU (Soybean meal replacement by NPN); C2 = TP-U vs. TP-PRU (conventional urea vs. post-immune urea); C3 = NPN-U-PRU vs. NPN-PRU (low and high post-ruminal urea-PRU level). The digestibility of dry matter, organic matter, and NDF was lower when soybean meal was replaced by non-protein nitrogen, also being different between the levels of post-ruminal urea used in the supplement. Ruminal pH was different when soybean meal was replaced by NPN (p = 0.003). Total concentration of short-chain fatty acids, concentrations of isobutyrate (p = 0.003), valerate (p = 0.001), and isovalerate (p = 0.001) were different, and blood urea was different when soybean meal was replaced by NPN (p = 0.006). Simpson’s diversity index was higher in the rumen of animals supplemented with TP-U than in those supplemented with TP-PRU (p = 0.05). A total of 27 phyla, 234 families, and 488 genera were identified. Nitrospirota and Gemmatimonadota phyla were detected just in the rumen of steers supplemented with TP-PRU. The performance (final BW, weight gain and gain per area) of the animals was different, being higher (p = 0.04) in animals supplemented with soybean meal, compared to NPN. The removal of soybean meal from the supplement and its replacement with either conventional urea plus post-ruminal urea or only post-ruminal urea compromises the performance of the animals. The lower the post-ruminal urea inclusion level, the lower the apparent digestibility of dry matter, organic matter, and NDF, when compared to animals supplemented with higher levels.

We aimed to investigate the effects of calcium-ammonium nitrate (CAN) fed to lactating dairy goats on dry matter (DM) intake, digestibility of nutrients, milk properties (composition, antioxidant capacity, fatty acid profile, and nitrate residues), and ruminal fermentation parameters. Twelve lactating Saanen goats averaging 98.5 ± 13.1 days in milk, 53.5 ± 3.3 kg of body weight, and 2.53 ± 0.34 kg of milk/day were randomly assigned in four 3 × 3 Latin squares to receive the following diets: a control group (without CAN) with 7.3 g/kg DM of urea (URE), 10 g/kg DM of CAN (CAN10), and 20 g/kg DM of CAN (CAN20). Each period lasted 21 days, with 14 days for diet adaptation and seven days for data and sample collection. The DM intake, digestibility of nutrients, yields of milk, 3.5% fat-corrected milk, and energy-corrected milk were not affected by treatments. Similarly, there were no treatment effects on the yields and concentrations of milk fat, true protein, and lactose, along with minor effects on milk fatty acid profile. Total antioxidant capacity in milk was unaffected by treatments; however, concentration of conjugated dienes increased, while thiobarbituric acid reactive substances in milk decreased linearly. Nitrate and nitrite residues in milk were elevated by treatments, while the total of volatile fatty acids and ammonia-N concentration in the rumen were unaffected. Collectively, feeding CAN (up to 20 g/kg of DM) to lactating dairy goats did not affect feed intake, nutrient digestibility, and milk composition; however, it may increase milk lipid oxidation, as evidenced by increased conjugated diene concentration.

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