Non-protein Nitrogen Source Research Articles

Dietary nucleotides drive changes in infant fecal microbiota in vitro and gut microbiota-gut-brain development in neonatal rats: A potential “nitrogen source” for early microbiota growth

Various dietary factors in human milk are important nutrients for the formation of the infant gut microbiota (GM). While promoting the growth of the GM, some human milk components that are difficult to absorb and utilize will be broken down by the GM, and converted into nutrients that the baby can use, such as breast milk oligosaccharides—the ‘carbon source’ for infant GM. This study reveals that nucleotides (NTs), significant non-protein nitrogen sources in human milk, can enhance the abundance of beneficial microbial genera such as g_Bifidobacterium, g_Bacteroides, and g_Blautia in in vitro fecal fermentation fluids of infants at low doses (2 mg/mL). Conversely, high doses of NTs (20 mg/mL) increased the abundance of g_Escherichia-Shigella. Furthermore, low-dose NTs fermentation broth significantly enhanced the expression of neurodevelopmental marker genes such as Tuj1, Sox2, Dcx, and NeuN in NE-4C neural stem cells, whereas a single NTs digestion broth did not exhibit significant activity. However, in vivo studies using neonatal rats as a model demonstrated that both low-dose NTs fermentation broth and NTs digestive juices promoted behavioral development in neonatal rats (PND 20) and neuron maturation in the prefrontal cortex and hippocampus. Non-targeted metabolomics results indicate that low-dose dietary NTs promote the production of certain neuroregulatory metabolites in infant fecal fermentation, such as uridine, L-tyrosine, L-glutamic acid, and succinic acid. These findings suggest that NTs may serve as an important “nitrogen source” during GM formation in early life and have a dose effect in driving the development of the microbiota-gut-brain axis in early life.

Carcass and Meat Characteristics of Cull Heifers from Different Genetic Groups Fed Diets with Different Sources of Nonprotein Nitrogen in Confinement.

The aim of this study was to evaluate the effect of genetic groups and diets with different sources of nonprotein nitrogen (NPN) on the carcass and meat characteristics of beef heifers. The meat from 40 heifers (20 ½ Angus ½ Nellore (A × N) and 20 ½ Charolais ½ Nellore (L × N)), finished in feedlots, was used. The heifers were fed diets containing different sources of NPN-(1) a diet with livestock urea and protected urea (LPU) and (2) a diet with extruded urea (EU)-in a completely randomized design with a 2 × 2 factorial arrangement. Carcass, composition and meat quality evaluations were carried out. There were no significant interactions between diet and genetic group for most of the variables evaluated (p > 0.05). The A × N heifers had higher hot carcass weights (305.73 vs. 279.80 kg), loin eye areas (80.87 vs. 75.45 cm2), subcutaneous fat thicknesses (8.69 vs. 6.35 mm) and lower shear forces (6.98 vs. 7.7 kg) compared to the C × N heifers (p < 0.05). The meat from the A × N heifers had higher proportions of saturated fatty acids (49.41 vs. 47.95%), with no effects on the proportions of monounsaturated (47.57%) and polyunsaturated (4.01%) fatty acids. The A × N heifers had better carcass and meat characteristics, while the C × N heifers had meat and fat with better fatty acid profiles.

Urea and nitrate poisoning as a source of non-protein nitrogen in ruminant diets: a review

The inclusion of non-protein nitrogen (NPN) as a partial replacement for true proteins is economically viable and does not compete with human food. However, excessive consumption of NPN by ruminants can be lethal due to poisoning. In this sense, the aim of this review was to describe the use of NPN in ruminant feeding and the consequences of ammonia and nitrate poisoning, including the poisoning mechanisms, recommended levels, prevention measures and treatments. Urea and nitrate are sources of NPN, and the toxic components are ammonia and nitrite, respectively. Excessive consumption of urea increases the hydrolysis of urea into ammonia, surpassing the use by the rumen microbiota. When the absorption of ammonia into the bloodstream exceeds the liver's capacity to assimilate it into urea, acute intoxication occurs, damaging the central nervous system. Nitrate poisoning occurs when consuming contaminated forage or water. The rumen microbiota reduces nitrate to nitrite and, subsequently, to ammonia. However, when nitrite reduction exceeds ammonia reduction, nitrite is absorbed into the bloodstream and oxidizes the iron atom in hemoglobin, transforming it into methemoglobin, which loses its ability to transport oxygen to tissues. It is concluded that ammonia and nitrate poisoning is influenced by the content of rapidly fermenting carbohydrates. Therefore, attention to the quality of nutrition and herd management is recommended to prevent outbreaks of poisoning.

Non-thermal technologies for broiler litter processing: Microbial safety, chemical composition, nutritional value, and fermentation parameters in vitro.

Annually, a massive amount of broiler litter (BL) is produced in the world, which causes soil and surface water pollution due to its high nitrogen content and microbial count. While ruminants can use this non-protein nitrogen (NPN) source for microbial protein synthesis. This issue becomes more critical when protein sources are unavailable or very expensive. One of the sources of NPN is BL which is produced at a considerable amount in the world yearly. This aim of this research was to conduct a survey of non-thermal technologies such as electrocoagulation (EC), ultraviolet (UV) radiation, and ultrasound (US) waves on the microbial safety and nutritional value of BL samples as a protein source in ruminant diets. The methodology of this study was based on the use of an EC device with 24V for 60min, UV-C light radiation (249nm) for 1 and 10min, and US waves with a frequency of 28kHz for 5, 10 and 15min to process BL samples compared with shade-dried samples. Chemical composition and nutritional values of processed samples were determined by gas production technique and measurement of fermentation parameters in vitro. Based on the results, microbial safety increased in the samples processed with the US (15min). The EC method had the best performance in reducing the number of fungi and mould. However, none of the methods could remove total bacteria and fungi. Digestibility of BL was similar in shade-dried, EC, and US (10min) treatments. In general, the use of EC and US15 without having adverse effects on gas production caused a decrease in the concentration of ammonia nitrogen. In contrast, it caused a decrease in neutral detergent fibre (NDF) in the investigated substrate. In general, it can be concluded that the use of US5 and EC methods without having a negative effect on the parameters of gas production and fermentation in vitro, while reducing NDF, causes a significant reduction in the microbial load, pathogens, yeast, and mould. Therefore, it is suggested to use these two methods to improve feed digestibility for other protein and feed sources.

Kinetics of transit and rumen degradation of processed fiber from seedbed straw according to different non-protein nitrogen sources

Kinetics of transit and rumen degradation of processed fiber from seedbed straw according to different non-protein nitrogen sources

Effect of dietary nitrogen content and ammonium phosphate inclusion on lysine requirement for nitrogen retention in growing pigs

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 &lt; 0.01). Plasma urea N decreased with increasing Lys ( P &lt; 0.05). Total plasma EAA content was reduced with NPN supplementation ( P &lt; 0.05), while content of Arg, Asp, Gln, and Glu was increased ( P &lt; 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.

Impact of Supplementing a Backgrounding Diet with Nonprotein Nitrogen on In Vitro Methane Production, Nutrient Digestibility, and Steer Performance.

Two experiments were conducted to evaluate the effect of nonprotein nitrogen (NPN) supplementation on in vitro fermentation and animal performance using a backgrounding diet. In experiment 1, incubations were conducted on three separate days (replicates). Treatments were control (CTL, without NPN), urea (U), urea-biuret (UB), and urea-biuret-nitrate (UBN) mixtures. Except for control, treatments were isonitrogenous using 1% U inclusion as a reference. Ruminal fluid was collected from two Angus-crossbred steers fed a backgrounding diet plus 100g of a UBN mixture for at least 35 d. The concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), and total gas and methane (CH4) production were determined at 24h of incubation. In experiment 2, 72 Angus-crossbred yearling steers (303 ± 29kg of body weight [BW]) were stratified by BW and randomly allocated in nine pens (eight animals/pen and three pens/treatment). Steers consumed a backgrounding diet formulated to match the diet used in the in vitro fermentation experiment. Treatments were U, UB, and UBN and were isonitrogenous using 1% U inclusion as a reference. Steers were adapted to the NPN supplementation for 17 d. Then, digestibility evaluation was performed after 13 d of full NPN supplementation for 4 d using 36 steers (12 steers/treatment). After that, steer performance was evaluated for 56 d (24 steers/treatment). In experiment 1, NPN supplementation increased the concentration of NH3-N and VFA (P < 0.01) without affecting the IVOMD (P = 0.48), total gas (P = 0.51), and CH4 production (P = 0.57). Additionally, in vitro fermentation parameters did not differ (P > 0.05) among NPN sources. In experiment 2, NPN supplementation did not change dry matter and nutrient intake (P > 0.05). However, UB and UBN showed lower (P < 0.05) nutrient digestibility than U, except for starch (P = 0.20). Dry matter intake (P = 0.28), average daily gain (P = 0.88), and gain:feed (P = 0.63) did not differ among steers receiving NPN mixtures. In conclusion, tested NPN mixtures have the potential to be included in the backgrounding diets without any apparent negative effects on animal performance and warrant further studies to evaluate other variables to fully assess the response of feeding these novel NPN mixtures.

Non-protein nitrogen supplementation on in vitro fermentation profile, methane production, and microbial nitrogen synthesis in a corn silage-based substrate.

Non-protein nitrogen (NPN) supplements improve animal performance in backgrounding diets. However, there is scarce information regarding the effect of different NPN sources and combinations on ruminal fermentation profile. The current study aimed to evaluate the effect of different NPN sources and their combinations on in vitro fermentation, microbial N synthesis, and methane (CH4) production in a backgrounding diet. Incubations were conducted on three separate days for 24h using corn silage and cotton gin byproduct (70% and 30% of DM, respectively) as substrate. Treatments were control (without NPN), urea, and five different proportions of urea-biuret and nitrate (100:0, 75:25, 50:50, 25:75, and 0:100). Each treatment, except control, was formulated to be isonitrogenous and equivalent to 1% urea inclusion. Ruminal fluid was collected from two ruminally cannulated Angus crossbred steers fed ad libitum corn silage and cotton gin byproduct plus 100g of a urea-biuret-nitrate mixture. The concentration of volatile fatty acids (VFAs) and ammonia nitrogen (NH3-N) were determined at 12 and 24h of incubation. Final pH, in vitro dry and organic matter digestibility, total gas production, and concentration of CH4 were determined at 24h. The supplementation of NPN increased (P < 0.05) the concentration of NH3-N at 12 and 24h. Although NPN supplementation increased (P < 0.05) the concentration of total VFA and acetate at 12h, treatments did not differ (P > 0.05) at 24h. Supplementation of NPN increased (P < 0.05) the proportion of acetate at 12 and 24h but tended to reduce (P = 0.054) the proportion of propionate only at 12h. Digestibility and pH were not different (P > 0.05) among treatments. Increasing nitrates in the NPN supplement increased (P < 0.05) the proportion of acetate and reduced (P < 0.05) the proportion of butyrate at 12 and 24h. The supplementation of NPN increased (P < 0.05) microbial N synthesis. Furthermore, increasing nitrate proportion in the NPN supplement increased (P < 0.05) the microbial N synthesis and efficiency of N use. Supplementation of NPN did not modify (P > 0.05) total gas or CH4 production. However, increasing nitrate proportion in the NPN supplement linearly reduced (P < 0.05) CH4 production. Supplementation of NPN increased NH3-N concentration and microbial N while increasing the inclusion of nitrate decreased the production of CH4 and increased the microbial N synthesis in a corn silage-based substrate under in vitro conditions.

PSX-23 Effects of Partial Or Total Nitrogen Replacement of Soybean Meal with Urea on Intake, Digestibility and Nitrogen Balance in Growing Nellore × Red Angus Bulls

Abstract In feedlot systems, feeding non-protein nitrogen sources, such as urea, instead of true protein sources, such as soybean meal (SBM), could be an alternative way to reduce dietary costs. This study aimed to evaluate the effects of partial or total replacement of SBM by urea on feed intake and apparent total-tract digestibility of organic matter (OM) and crude protein (CP), and on nitrogen (N) balance in bulls. Four Nellore × Red Angus crossbred bulls (292 ± 14.6 kg BW) were randomly assigned to treatment in a 4×4 Latin square design. The experimental treatments consisted of different replacement levels of SBM by urea (DM basis): 0% replacement (R-0%); 54% replacement (R-54%); 78% replacement (R-78%); 100% replacement (R-100%). Diets were formulated according to the BR-CORTE system to provide approximately 130 g CP/kg DM. The diets consisted of 20% corn silage and 80% ground corn-based concentrate containing SBM and/or urea+ammonium sulfate, mineral mix, and virginiamycin. Each experimental period was 21 d, with 14 d adaptation, and 4 d of total feces and urine collection. Data were analyzed using the MIXED procedure in SAS and statistical significance was declared at P &amp;lt; 0.05. Dietary treatment did not influence (P &amp;gt; 0.05) OM and CP intake. Apparent total-tract OM and CP digestibility were not influenced (P &amp;gt; 0.05) by dietary treatment. Daily total urinary and fecal N were not influenced (P &amp;gt; 0.05) by dietary treatment. Dietary treatment did not influence (P &amp;gt; 0.05) N retention. Therefore, these data suggest that SBM may be partially or totally replaced by urea as the dietary N source without affecting feed intake, apparent total-tract digestibility, and N balance in Nellore × Red Angus crossbreed young bulls fed a high concentrate diet.

Metabolic Profile of F1 Holstein × Zebu Lactating Dairy Cows Under Grazing Supplemented with Two Non-Protein Nitrogen Sources

Pastures dedicated to cattle production in Venezuela have a low crude protein concentration. One of the nutritional strategies to correct the forage protein deficit is using non-protein nitrogen in the diet. To evaluate the effect of two non-protein nitrogen sources on the metabolic profile of lactating dairy cows, 31 F1 Holstein × Zebu multiparous cows averaging 419 ± 46 kg body weight and 17.1 ± 3.3 kg milk·animal·d-1 were randomly assigned to two treatments for 91 days: 1) 59 g·animal-1·d-1 of urea and 2) 64 g·animal-1·d-1 of Optigen II® as slow-release urea (SRU). The animals were grazing (2.12 AU·ha-1) on Urochloa decumbens, U. humidicola, and U. brizantha (7.98-9.61 % CP) and supplied with 4 kg·animal·d-1 of concentrate (15 % CP), and 108, 60, and 108 g·animal·d-1 of mineral, molasses, and bypass fat, respectively. Glucose, total protein, albumin, cholesterol, urea, and β-hydroxybutyrate concentrations, aspartate aminotransferase, and gamma-glutamyl transferase activities were determined in blood serum samples every 28 days. ANOVA analyzed data in a completely randomized design with repeated measures. There were no differences among treatments in the parameters investigated; however, collecting time influenced all of them. No treatment × time interactions were found except for albumin concentration, higher in urea at day 0. The results indicate that under the conditions assayed in the present work, Optigen II® offers no advantage over urea concerning blood indicators of energy and protein metabolism and hepatic functionality in dairy cows.

Nitrogen Utilization in Goats Consuming Buffelgrass Hay and Molasses-Based Blocks with Incremental Urea Levels.

The use of goats for meat production faces challenges from environmental and nutritional factors. Urea is an affordable non-protein nitrogen source commonly utilized in ruminant nutrition. The objective of this study was to investigate nitrogen utilization in goats fed low-quality hay supplemented with molasses blocks containing urea. Twenty Anglo-Nubian doelings were individually housed in metabolic cages and provided with chopped Buffelgrass (Cenchrus ciliaris) hay ad libitum. Goats were randomly assigned to four urea levels (0, 2, 4, and 6%; n = 5 per treatment) in molasses blocks for a duration of 30 days. A negative nitrogen balance (-2.458 g/day) was observed in doelings consuming blocks without urea, compared with a positive balance (0.895 g/d) for those consuming the 6% urea blocks. Block nitrogen intake significantly increased with urea level, but urea supplementation did not affect dry matter (DM) or neutral detergent fiber (NDFom) intake or digestibility. A minimum crude protein (CP) requirement of 8% for maintenance in doelings consuming low-quality forage with a urea-based supplement was determined through regression analysis between CP intake (% of DM) and N balance (r2 = 0.479; p < 0.002). The value of 8% of CP obtained in this study is similar to several previous studies reported in the literature, but in this case, the increments in CP came exclusively from urea. In this study, increasing the urea content of molasses blocks up to 6% significantly increased nitrogen intake, retention, and balance in goats. These results contribute to a better understanding of nitrogen utilization in goats fed low-quality hay with urea supplementation.

Effect of nitrate supplementation, dietary protein supply, and genetic yield index on performance, methane emission, and nitrogen efficiency in dairy cows

The objective was to investigate the effect of nonprotein nitrogen source, dietary protein supply, and genetic yield index on methane emission, N metabolism, and ruminal fermentation in dairy cows. Forty-eight Danish Holstein dairy cows (24 primiparous cows and 24 multiparous cows) were used in a 6 × 4 incomplete Latin square design with 4 periods of 21-d duration. Cows were fed ad libitum with the following 6 experimental diets: diets with low, medium, or high rumen degradable protein (RDP):rumen undegradable protein (RUP) ratio (manipulated by changing the proportion of corn meal, corn gluten meal, and corn gluten feed) combined with either urea or nitrate (10 g NO3-/kg of dry matter) as nonprotein nitrogen source. Samples of ruminal fluid and feces were collected from multiparous cows, and total-tract nutrient digestibility was estimated using TiO2 as flow marker. Milk samples were collected from all 48 cows. Gas emission (CH4, CO2, and H2) was measured by 4 GreenFeed units. We observed no significant interaction between dietary RDP:RUP ratio and nitrate supplementation, and between nitrate supplementation and genetic yield index on CH4 emission (production, yield, intensity). As dietary RDP:RUP ratio increased, intake of crude protein, RDP, and neutral detergent fiber and total-tract digestibility of crude protein linearly increased, and RUP intake linearly decreased. Yield of milk, energy-corrected milk, and milk protein and lactose linearly decreased, whereas milk fat and milk urea nitrogen concentrations linearly increased as dietary RDP:RUP ratio increased. The increase in dietary RDP:RUP ratio resulted in a linear increase in the excretion of total purine derivatives and N in urine, but a linear decrease in N efficiency (milk N in % of N intake). Nitrate supplementation reduced dry matter intake (DMI) and increased total-tract organic matter digestibility compared with urea supplementation. Nitrate supplementation resulted in a greater reduction in DMI and daily CH4 production and a greater increase in daily H2 production in multiparous cows compared with primiparous cows. Nitrate supplementation also showed a greater reduction in milk protein and lactose yield in multiparous cows than in primiparous cows. Milk protein and lactose concentrations were lower for cows receiving nitrate diets compared with cows receiving urea diets. Nitrate supplementation reduced urinary purine derivatives excretion from the rumen, whereas N efficiency tended to increase. Nitrate supplementation reduced proportion of acetate and propionate in ruminal volatile fatty acids. In conclusion, no interaction was observed between dietary RDP:RUP ratio and nitrate supplementation, and no interaction between nitrate supplementation and genetic yield index on CH4 emission (production, yield, intensity) was noted. Nitrate supplementation resulted in a greater reduction in DMI and CH4 production, and a greater increase in H2 production in multiparous cows than in primiparous cows. As the dietary RDP:RUP ratio increased, CH4 emission was unaffected and RDP intake increased, but RUP intake and milk yield decreased. Genetic yield index did not affect CH4 production, yield, or intensity.

Formulasi dan Evaluasi Tablet Urea Lepas Lambat Berlapis Biopolimer Poliasam Laktat Sebagai Suplemen Ruminansia

Urea is a source of non-protein nitrogen (NPN) which can be used to replace pure protein in ruminants. Urea is easily soluble and is degraded to ammonia by rumen bacteria, thus affecting the quality of ruminants. To increase the utilization of urea as a supplement is to try to slow its release into ammonia in the rumen so that it can be used efficiently by rumen microbes to form microbial protein. Slow release urea tablets as an alternative can control the rate of urea degradation and release of ammonia into the rumen and increase rumen efficiency. This study aims to determine the rate and pattern of release of urea tablets in the rumen so that their use is more practical and the dosage is correct. To maintain ammonia levels in the rumen, an alternative polymer-coated urea slow release tablet was designed. Based on this, it was carried out to manufacture slow release urea tablets with biopolymer polylactic acid (PLA) coating in the rumen fluid of ruminants. Furthermore, an in vitro evaluation was carried out by measuring pH into rumen fluid and measuring NH3 by UV-Vis spectro analysis at a wavelength of 630 nm. The results of the test for urea release in the rumen in formulas 1, 2 and 3 were 75.133%, 76.076% and 74.051% respectively, while the release of urea in uncoated urea tablets was 96.384%, these results indicate that tablets with lactic acid coated polyacid last longer. release compared to urea tablets without biopolymer coating.

Effects of extruded urea levels on the productive performance and carcass and meat characteristics of Nellore cattle.

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 22months and an average initial weight of 333.5kg, were used. A completely randomized design was used with four treatments: 50, 60, 70, and 80g/100kg 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 479.18kg and 1.02kg/day with the inclusion of 59.71, 54.14, and 54.16g/100kg BW of extruded urea, respectively. There was no effect (P > 0.05) of extruded urea levels on hot carcass weight (233.3kg), carcass yield (53.2%), ribeye area (72.7 cm2), and subcutaneous fat thickness (5.3mm). 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 70g/100kg BW of extruded urea in the diet for finishing Nellore steers in confinement.

PERFORMANCE AND HAEMATOLOGICAL INDICES OF BALAMI RAMS FED CATTLE URINE-ENSILED SORGHUM STOVER AS SOURCE OF NON-PROTEIN NITROGEN

A 90-days feeding trial was conducted to evaluate the effect of replacing fertilizer grade urea with cattle urine in sorghum stover silage on the performance and haematological indices of Balami rams. Five diets were formulated. Diet 1 (control) contained sorghum stover ensiled with fertilizer grade urea (FGU) while diets 2, 3, 4 and 5 had 25, 50, 75 and 100% levels of cattle urine as replacement for FGU. Twenty (20) rams of the Balami breed were allotted to the five diets in replicates of four in a completely randomized design. Data on daily feed intake, weight gain and haematological indices were collected Results showed no significant influence of cattle urine on daily feed intake. However, Daily weight gain was significantly (P&lt;0.05) higher on T5 (128.11 g) and T4 (124.08 g) which were the same, than on other diets which also did not differ (101.67 – 103.65 g). Similarly, Rams fed T5 (34.53 kg) had higher (P&lt;0.05) final weight than those on other diets which were the same (30.30 – 31.93 kg). Feed conversion ratio was significantly (P&lt;0.05) better on T5 (5.74) and T4 (5.88) compared to T1 (7.19), T2 (7.13) and T3 (7.06) which were poorer. All haematological indices did not significantly differ among diets. It was therefore concluded that cattle urine can completely replace fertilizer grade urea as silage additive in sorghum stover and as non-protein nitrogen source in balami rams diets.

Isolation and pan-genome analysis of Enterobacter hormaechei Z129, a ureolytic bacterium, from the rumen of dairy cow.

Urea is an important non-protein nitrogen source for ruminants. In the rumen, ureolytic bacteria play critical roles in urea-nitrogen metabolism, however, a few ureolytic strains have been isolated and genomically sequenced. The purpose of this study was to isolate a novel ureolytic bacterial strain from cattle rumen and characterize its genome and function. The ureolytic bacterium was isolated using an anaerobic medium with urea and phenol red as a screening indicator from the rumen fluid of dairy cattle. The genome of isolates was sequenced, assembled, annotated, and comparatively analyzed. The pan-genome analysis was performed using IPGA and the biochemical activity was also analyzed by test kits. A gram-positive ureolytic strain was isolated. Its genome had a length of 4.52 Mbp and predicted genes of 4223. The 16S rRNA gene and genome GTDB-Tk taxonomic annotation showed that it was a novel strain of Enterobacter hormaechei, and it was named E. hormaechei Z129. The pan-genome analysis showed that Z129 had the highest identity to E. hormaechei ATCC 49162 with a genome average nucleotide identity of 98.69% and possessed 238 unique genes. Strain Z129 was the first E. hormaechei strain isolated from the rumen as we know. The functional annotation of the Z129 genome showed genes related to urea metabolism, including urea transport (urtA-urtE), nickel ion transport (ureJ, tonB, nixA, exbB, exbD, and rcnA), urease activation (ureA-ureG) and ammonia assimilation (gdhA, glnA, glnB, glnE, glnL, glsA, gltB, and gltD) were present. Genes involved in carbohydrate metabolism were also present, including starch hydrolysis (amyE), cellulose hydrolysis (celB and bglX), xylose transport (xylF-xylH) and glycolysis (pgi, pgk, fbaA, eno, pfkA, gap, pyk, gpmL). Biochemical activity analysis showed that Z129 was positive for alkaline phosphatase, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, α-glucosidase, β-glucosidase, and pyrrolidone arylaminase, and had the ability to use D-ribose, L-arabinose, and D-lactose. Urea-nitrogen hydrolysis rate of Z129 reached 55.37% at 48 h of incubation. Therefore, the isolated novel ureolytic strain E. hormaechei Z129 had diverse nitrogen and carbon metabolisms, and is a preferred model to study the urea hydrolysis mechanism in the rumen.

Assessment of the application for renewal of the authorization of a feed additive consisting of urea for ruminants (Borealis L.A.T. GmbH, SKW Stickstoffwerke Piesteritz GmbH and Yara France).

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 Panelconsiders 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 Panelis not in the position to conclude on the user safety. The Panelretains that previously made conclusion on the efficacy remains valid.

Intoxicação por ureia em bovinos: breve revisão e abordagem diagnóstica

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.

Feeding behaviour of beef cattle in intensive finishing on pasture and supplemented with different additives

Context Concentrate supplementation at high rates represents a method used to improve the productive efficiency of the beef cattle grazing system. Further, the use of additives increases the nutrient-use efficiency of diets. In this sense, it is important to determine the impact of additives in grazing beef cattle fed with high-concentrate supplements to determine the appropriate management practices of the system. Aim This study aimed to evaluate the feeding behaviour of Nellore beef cattle (Bos taurus indicus) in intensive finishing on pasture and fed with different additives. Methods Twenty-eight Nellore cattle [with initial bodyweight (BW) of 480 ± 5 kg and age of 24 ± 2 months] were finished on Urochloa brizantha cv. BRS Piatã pastures. The animals were assigned to a completely randomised design with four experimental supplements: U (urea as non-protein nitrogen source), UO (slow-release urea partially replacing urea), UOL (supplement UO + Saccharomyces cerevisiae yeast), and UOLP (supplement UOL + multi-strain probiotics). Key results Supplement intake and idleness time were most affected by the season (P &lt; 0.001). The total dry-matter intake was higher in UOLP (P &lt; 0.004), and this supplement also produced the least effects on feeding behaviour. Conclusion The beginning of the rains affected the feeding behaviour. The additive combination in intensive finishing on pasture, such as UOL and UOLP, improved the intake and did not affect the feeding behaviour during the day. Implications These results indicate that the use of additives in intensive finishing on pasture improves productive efficiency and does not change the animal’s behaviour, resulting in an important technology to be disseminated and applied by grazing beef cattle producers.

Intoxication Induced by Urea Containing Diets in Broiler Chickens: Effect on Weight Gain, Feed Conversion Ratio, Hematological and Biochemical Profiles

Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, and hematological and biochemical profiles. A total of 48 broiler chicks were randomly allotted into 4 groups, designated Groups 1, 2, 3 and 4 of 12 birds each. Birds in Groups 2, 3 and 4 were fed on diets containing urea at the levels of 1%, 2.5% and 4%, respectively. Birds in Group 1 served as control and were not exposed to urea. Experimentation period was for 3 weeks and experiment was terminated when birds were 42 days of age. Body weight of all intoxicated birds at the various intervals was significantly decreased in comparison with that of the untreated control. Compared with control, all intoxicated broilers manifested significant (P ≤ 0.05) decrease in all hematological parameters involving erythrocytic and total leucocytic counts, Hemoglobin (Hb) and Packed Cell Volume (PCV) on a dose- and time-pattern. In comparison with the control levels, biochemical profile of the intoxicated birds disclosed significant decrease in blood glucose level and significant increase in serum uric acid, urea, Alkaline Phosphatase (ALP) and Lactate Dehydrogenase (LDH) levels. Based upon the present data, it was concluded that the addition of urea to broiler diets bears serious sequences concerning the general health condition, performance, weight gain, and hematological and biochemical profiles.