Urine Urea Concentration Research Articles

225 Kidney function and nitrogen excretion in Brown Swiss and Holstein dairy cows

Abstract The agricultural sector contributes to nitrogen (N) emissions since farm animals excrete considerable N amounts via feces and urine. To reduce N emissions by dairy cattle, methods predicting accurately individual N emissions are of great interest. Recent data showed that Brown Swiss (BS) cows have greater urea concentrations in milk and blood than Holstein (HO) cows. However, it is still unknown if greater BUN concentrations in a particular breed are congruently reflected by concomitantly increased contents of nitrogenous compounds in other media (e.g., urine and saliva). Thus, the present study simultaneously assessed biomarkers for kidney function like urea, and creatinine and symmetric dimethylarginine (SDMA) concentrations in several body fluids (i.e., blood, urine, milk, and saliva) as well as nitrogen excretion in feces in BS and HO cows under identical feeding conditions. Blood, saliva, urine, and feces were sampled in 31 multiparous BS and 46 HO cows kept under identical feeding and management conditions. Samples were collected at different lactational stages after the monthly DHIA control test-day. Concentrations of urea and creatinine were measured in serum, urine, and saliva. Symmetric dimethylarginine was determined in serum, which is an established indicator for glomerular filtration rate (GFR). Feces were analyzed for dry matter content and nitrogen concentrations. Data on milk urea and protein concentrations, and daily milk yield were obtained from the monthly DHIA test-day records. The effects of breed, time, and parity number on blood, saliva, urine, feces, and milk parameters were evaluated with the GLM procedure with breed, time, and parity number as fixed effects. Differences between BS and HO were assessed by the Tukey-corrected t-test at P < 0.05. Dry matter intake and body weight were similar in BS and HO cows (P > 0.05). No differences between BS and HO were observed for milk yield, fecal DM and nitrogen content. BS cows showed greater urea concentration (25.8 ± 0.7 vs 21.8 ± 0.7 mg/dL), and protein content in milk (3.70 ± 0.08 vs 3.45 ± 0.07%) than HO cows (P < 0.01). Concentrations of urea, creatinine, and SDMA in serum, were greater in BS than in HO cows (P < 0.01) with 5.46 ± 0.19 vs 4.72 ± 0.13 mmol/L for urea, 105.96 ± 2.23 vs 93.07 ± 1.50 mmol/l creatinine, and 16.78 ± 0.69 vs 13.39 ± 0.44 µg/dL SDMA, respectively. Urea and creatinine concentrations in urine and saliva did not differ among breeds. Despite greater urea and creatinine concentrations in blood, and milk urea content in BS compared with HO, excretion of these parameters did not differ between breeds in urine. Our results suggest a reduced renal glomerular filtration rate in BS compared with HO. The underlying mechanisms require further investigations.

Kidney function, but not nitrogen excretion, differs between Brown Swiss and Holstein dairy cows

Brown Swiss (BS) cows have greater urea concentrations in milk and blood compared with Holstein (HO) cows. We tested the hypothesis that BS and HO cows differ in kidney function and nitrogen excretion. Blood, saliva, urine, and feces were sampled in 31 multiparous BS and 46 HO cows kept under identical feeding and management conditions. Samples were collected at different lactational stages after the monthly DHIA control test-day. To test the glomerular filtration rate (GFR) and urea excretion, concentrations of creatinine and urea were measured in serum, urine, and saliva. As an additional marker to estimate GFR, we determined symmetric dimethylarginine (SDMA) in serum. Feces were analyzed for dry matter content and nitrogen concentration. Data on milk urea and protein concentrations, and daily milk yield were obtained from the monthly DHIA test-day records. The effects of breed, time, and parity number on blood, saliva, urine, feces, and milk parameters were evaluated with the GLM procedure with breed, time, and parity number as fixed effects. Differences between BS and HO were assessed by the Tukey-corrected t-test at P < 0.05. Concentrations of urea, creatinine, and SDMA in serum, were greater in BS than in HO cows (P < 0.01): 5.46 ± 0.19 vs 4.72 ± 0.13 mmol/L (urea), 105.96 ± 2.23 vs 93.07 ± 1.50 mmol/l (creatinine), and 16.78 ± 0.69 vs 13.39 ± 0.44 µg/dL (SDMA). We observed a greater urea concentration in BS cows (25.8 ± 0.7 vs 21.8 ± 0.7 mg/dL) and protein content in milk (3.70 ± 0.08 vs 3.45 ± 0.07%) than in HO cows (P < 0.01). Urea and creatinine concentrations in urine and saliva did not differ among breeds. No differences between BS and HO were observed for milk yield, fecal DM, and fecal nitrogen content. Dry matter intake and body weight were similar in BS and HO cows (P > 0.05). Despite greater urea, creatinine, and SDMA concentrations in blood as well as a higher milk urea content in BS compared with HO, respective concentrations in urine did not differ between breeds. In conclusion, our results demonstrate a lower renal GFR in BS compared with HO cows, thereby contributing to the greater plasma urea concentration in BS cows. However, estimation of nitrogen excretion via milk, urine, and feces does not entirely reflect nitrogen turnover within the animal.

Effects of different concentrate levels in AGRI-002E sorghum silage-based diets on nutrient intake and digestibility, ruminal pH and ammonia concentration, ruminal degradability, and microbial efficiency in beef cattle

This study aimed to evaluate the effect of increasing concentrate levels in AGRI-002E sorghum silage (SS)-based diets on nutrient intake and digestibility, ruminal pH and ammonia concentration, Nitrogen (N) balance, efficiency of microbial protein synthesis, and in situ degradability of complete diets. Five rumen-cannulated Nellore bulls (age = 8 ± 1.0 months; initial BW = 242 ± 5 kg) received five dietary treatments in a 5×5 Latin square experimental design. The dietary treatments consisted of five concentrate levels (0, 200, 400, 600, and 800 g of concentrate/kg on a DM basis) in SS-based diets. The experiment lasted 120 d, with five periods of 24 d. Each period consisted of 17 d for dietary adaptation, and 7 d for data collection. In situ degradability assays were conducted to estimate ruminal degradability. Total feces and urine collection were performed to estimate nutrient intake and digestibility and estimate N balance. Omasal and ruminal digesta collection were performed to estimate ruminal digestibility and ruminal parameters. Increasing concentrate levels in SS-based diets led to linear increases (P<0.001) in the intake of dry matter (DM), organic matter (OM), crude protein (CP), and ether extract (EE). Neutral detergent fiber corrected for ash and protein contamination (apNDF) and starch intake showed quadratic responses (P≤0.008). Ruminal digestibility of DM, OM and CP responded quadratically (P≤0.040), while apNDF exhibited linear decrease (P=0.003). Starch ruminal digestibility exhibited a cubic effect (P=0.016). Apparent total-tract digestibility of DM, OM, and EE increased linearly (P≤0.001), whereas apNDF, and CP digestibility decreased linearly (P≤0.012), and starch presented a quadratic effect (P=0.029). In situ ruminal degradation parameters increased linearly with higher concentrate levels (P<0.001). Ruminal pH exhibited a quadratic pattern (P=0.006), ammonia concentration linearly decreased (P=0.003). Total volatile fatty acids, and butyrate showed linear increases (P<0.001), acetate and propionate had quadratic effects (P<0.001), while the ratio Acetate to Propionate decreased linearly (P<0.001). N intake, fecal N excretion, retained N, total digestible nutrients, digestible organic matter, and microbial production increased linearly (P<0.001), although urine N excretion, urinary urea, and blood urea concentration decreased linearly (P<0.028). Therefore, increasing concentrate levels in AGRI-002E sorghum silage-based diets improve TDN intake, microbial protein synthesis efficiency, in situ ruminal degradability parameters, and nitrogen utilization. Moreover, our findings indicate that AGRI-002E sorghum silage demonstrates potential as a fiber source for high-concentrate diets. However, its effectiveness is limited without concentrate supplementation, emphasizing the importance of balanced dietary composition for optimal utilization in beef cattle.

Urine high-sensitive troponin I in children cannot offer an applicable alternative to serum.

In children, congenital heart defects represent the primary cause of increased serum troponin I. The elimination process of cardiac troponin I from the bloodstream and the factors influencing this process remain unknown. The objective of this study was to explore the role of troponin I as an indicator of cardiac damage in children both in serum and urine, a concept previously investigated in adults. Our prospective study involved 70 children under 24 months of age. The first group underwent ventricular septal defect repair, while the second group involved children who had undergone partial cavopulmonary anastomosis. For these groups, urine and serum troponin I were assessed on four occasions. The third group, consisting of healthy children, underwent a single measurement of urine troponin I. Serum troponin I values exhibited an expected elevation in the early postoperative period, followed by a return to lower levels. Significantly higher concentrations of serum troponin I were observed in the first group of children (p < 0.05). A positive correlation was found between troponin I in the first three measurements and cardiopulmonary bypass and aortic cross-clamping time. There was no discernible increase in urine troponin I directly related to myocardial damage; troponin I couldn't be detected in most urine samples. The inability to detect troponin I in urine remains unexplained. Potential explanatory factors may include the isoelectric point of troponin I, elevated urinary concentrations of salts and urea, variations in urine acidity (different pH levels), and a relatively low protein concentration in urine.

Physiological Functions of Aquaporin-3 in Mediating Water and Solutes

Aquaporins (AQP), are a family of membrane channel proteins that facilitate the transmembrane diffusion of water and some small non-charged solutes such as glycerol and urea by osmosis or solute gradient. AQP3, an aquaglyceroporin, is expressed in the kidney, skin, and testes, etc. Mice lacking AQP3 have symptoms of diabetes insipidus. In addition, the absence of AQP3 leads to dry skin in mice. AQP4 is permeable to water only. To understand the specific function of the water permeability and small solute transport mediated by AQP3, we generated AQP3 knock-out (AQP3 KO) mice and AQP4 knock-in mice (AQP4 KI) with AQP4 replacing AQP3 in situ. In the basal condition, knock-out of AQP3 in mice led to increased urine volume, decreased urine osmolality and tubule dilation. Interestingly, in AQP4 KI mice, these phenomena were reversed, showing improved urine concentration and tubular morphology. However, there was no significant difference in non-urea solute concentrations between both genotypes. Subsequently, we conducted acute urea loading tests and high-protein diet experiments to further increase the production and excretion of urea in mice. The experimental results showed that both urea loading and high-protein diet had little impact on urine osmolality and urinary urea concentration in AQP3 KO mice. But the urine osmolality and urinary urea concentration in AQP4 KI mice were altered by exogenous administration of urea. Our data indicates that the absence of AQP3 prevents urea accumulation in the kidney, disrupting urine concentration mechanism. The knock-in of AQP4 can restore AQP3 mediated water channel function and help to regulate the urine concentration ability. The water permeability, other than solute transport, of AQP3 plays important role in urine concentrating mechanism. AQP3 KO mice exhibited significant epidermal thickening, excessive keratinization, decreased skin hydration and elasticity. The replacement of AQP4 in situ did not improve these phenomena, indicating that solute transport mediated by AQP3 may play a role in maintaining normal skin function. Therefore, we constructed a mouse model of psoriasis induced by imiquimod (IMQ). It was found that AQP3 expression was reduced in the lesional skin of wildtype (WT) mice, while AQP3 KO mice and AQP4 KI mice exhibited dry skin, excessive epidermal proliferation, and increased inflammatory response. Local treatment with urea (10%) could alleviate these symptoms. These experimental results confirmed the important role of AQP3 in the pathogenesis of psoriasis and the potential role of urea in the treatment of psoriasis. Our study suggests the diverse physiological functions of AQP3 in different tissues. This research was supported by Beijing Natural Science Foundation (7232249). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Urease-Powered Black TiO2 Micromotors for Photothermal Therapy of Bladder Cancer.

Urease-powered nano/micromotors can move at physiological urea concentrations, making them useful for biomedical applications, such as treating bladder cancer. However, their movement in biological environments is still challenging. Herein, Janus micromotors based on black TiO2 with urease asymmetric catalytic coating were designed to take benefit of the optical properties of black TiO2 under near-infrared light and the movement capability in simulated bladder environments (urea). The black TiO2 microspheres were half-coated with a thin layer of Au, and l-Cysteine was utilized to attach the urease enzyme to the Au surface using its thiol group. Biocatalytic hydrolysis of urea through urease at biologically relevant concentrations provided the driving force for micromotors. A variety of parameters, such as urea fuel concentration, viscosity, and ionic character of the environment, were used to investigate how micromotors moved in different concentrations of urea in water, PBS, NaCl, and urine. The results indicate that micromotors are propelled through ionic self-diffusiophoresis caused by urea enzymatic catalysis. Due to their low toxicity and in vitro anticancer effect, micromotors are effective agents for photothermal therapy, which can help kill bladder cancer cells. These promising results suggest that biocompatible micromotors hold great potential for improving cancer treatment and facilitating diagnosis.

Optimal protein concentration in diets for sows during the transition period.

The aim of the present study was to determine the optimal concentration of dietary protein required in transition diets for multiparous sows that enhance the farrowing process, colostrum production, and subsequent lactation performance. Forty-eight multiparous sows were allotted to one of six dietary treatments according to body weight (290 ± 3kg) and parity (3.8 ± 0.2) from day 108 of gestation until 24hafter the onset of farrowing. The diets were isoenergetic and contained increasing concentrations of dietary protein (expressed as standardized ileal digestible [SID] Lys) and were supplied at a daily feed supply of 3.8kg. On day 108 of gestation and days 2, 7, 14, 21, and 28 of lactation, body weight, and back fat thickness were recorded, and blood was sampled on day 108 of gestation, at the onset of farrowing, and days 3, 10, 17, and 24 of lactation from the sows for analysis of plasma metabolites. On day 115 of gestation, urine, and feces were collected for nitrogen (N) balance. The number of liveborn and stillborn piglets and time of birth were recorded and blood from every fourth piglet was sampled at birth for blood gas analysis. Piglets were weighed individually from birth until weaning, to estimate the colostrum and milk yield of the sows. Colostrum and milk samples were collected, and their compositions were determined. On days 3 and 28 of lactation, sows were injected with deuterium oxide to estimate body composition. The N utilization was maximized when the concentration of SID Lys in the transition diet was 6.06g/kg (P < 0.01). When urinary concentrations of urea were expressed relative to creatinine, the relative concentration of urea remained low until a dietary concentration of 6.08g SID Lys/kg, above which the relative concentration of urea increased (P < 0.01). Stillbirth rate increased linearly with increasing SID Lys concentration in the transition diet (P < 0.001), thus the concentration of SID Lys should be kept as low as possible without impairing sow performance excessively. A carry-over effect on milk yield was observed, showing that a dietary SID Lys concentration of 5.79g/kg during transition optimized milk production at an average yield of 13.5kg/d (P = 0.04). Increasing loss of body fat in lactation was observed with increasing SID Lys concentration in the transition diet (P = 0.03). In conclusion, the transition diet of multiparous sows should contain 5.79g SID Lys/kg when fed 3.8kg/d (13.0 MJ ME/kg), for a total SID Lys intake of 22g/d.

Influence of urinary urea concentration on hemolytic activity and cytotoxicity of uropathogenic Morganella morganii strain

Influence of urinary urea concentration on hemolytic activity and cytotoxicity of uropathogenic Morganella morganii strain

Mammary gland, kidney and rumen urea and uric acid transporters of dairy cows differing in milk urea concentration

The milk urea concentration (MUC) serves as indicator of urinary nitrogen emissions, but at comparable crude protein (CP) intake, cows with high (HMU) and low (LMU) MUC excrete equal urea amounts. We hypothesized that urea and uric acid transporters and sizes of the kidney, mammary gland, and rumen account for these phenotypes. Eighteen HMU and 18 LMU Holstein dairy cows fed a low (LP) and normal (NP) CP diet were studied. Milk, plasma and urinary urea concentrations were greater with NP feeding, while plasma and urinary urea concentrations were comparable between phenotypes. Milk and plasma uric acid concentrations were higher with LP feeding but not affected by phenotype. The milk-urine uric acid ratio was greater in HMU cows. The mRNA expressions of the ruminal urea transporter SLC14A1 and AQP10, the mammary gland and rumen AQP3, and the mammary gland uric acid transporter ABCG2 were not affected by group or diet. Renal AQP10, but not AQP3, AQP7, and SLC14A2 expressions, and the kidney weights were lower in HMU cows. These data indicate that renal size and AQP10 limit the urea transfer from blood to urine, and that MUC determines if uric acid is more released with milk or urine.

THU112 Effect Of Protein Supplementation On Plasma Sodium Levels And Urinary Urea Excretion In Patients With Chronic Siad—A Monocentric Open-Label Proof-Of-Concept Study—The Treasure Study

Abstract Disclosure: S. Monnerat: None. C. Atila: None. F.E. Baur: None. M. Dickenmann: None. M. Christ-Crain: None. INTRODUCTION The syndrome of inappropriate antidiuresis (SIAD) is the most common cause of euvolemic hyponatremia. Besides fluid restriction, increasing free-water clearance is an effective treatment approach that can be achieved through osmotic diuresis by administering oral urea. However, oral urea has a very peculiar taste that impedes long-term compliance. Dietary proteins are metabolized into soluble excretable urea by the liver. We hypothesized that dietary protein could increase free water clearance through urea-induced osmotic diuresis and therefore aimed to investigate the effect of high-protein supplementation on plasma sodium levels in outpatients with chronic SIAD. METHODS This is an interim analysis of a monocentric open-label proof-of-concept trial conducted at the University Hospital of Basel since October 2021. Adult outpatients with chronic SIAD of any etiology were eligible. Patients received 90g protein daily for 7 days in the form of protein powder dissolved in a maximum of 1L of liquid of choice. After a wash-out period of at least a week, patients received 30g of oral urea daily for 7 days. Patients were asked to keep their baseline fluid intake unchanged throughout the study. The primary endpoint was the increase in sodium levels from baseline to the end of the 7-day protein supplementation. RESULTS Thirteen patients, 10 females and 3 males, with chronic SIAD were included. Median [IQR] age was 63 [61, 80] and the median [IQR] duration of hyponatremia was 33 months [12, 42]. At baseline, median [IQR] plasma sodium concentration was 130 mmol/L [129, 133]. Eight patients had mild hyponatremia (130-134 mmol/L), 4 had moderate hyponatremia (125-129 mmol/L), and 1 patient had profound hyponatremia (&amp;lt;125 mmol/L). After 7 days of 90g daily protein supplementation (n = 13), sodium levels increased by a median [IQR] of 3 mmol/L [0, 5], blood urea nitrogen increased by a median [IQR] of 4.3 mmol/L [1.7, 5.1] and urinary urea corrected for urine creatinine increased by a median [IQR] of 26.0 mmol/mmol [17.1, 32.3]. After 7 days of oral urea (n = 8), sodium levels increased by a median [IQR] of 2 mmol/L [1, 3], blood urea nitrogen increased by a median [IQR] of 8.5 mmol/L [3.8, 10.2] and urinary urea corrected for urine creatinine increased by a median [IQR] of 31 mmol/mmol [21.1, 39.8]. CONCLUSION This interim analysis suggests that high-protein supplementation with protein powder increases plasma sodium levels in patients with chronic SIAD. The increase in urea concentration in both plasma and urine upon protein supplementation is comparable to the increase upon oral urea administration, which supports protein-induced ureagenesis to be the underlying mechanism of action. Presentation: Thursday, June 15, 2023

The effects of feeding sodium chloride pellets on the gastric mucosa, acid-base, and mineral status in exercising horses.

Electrolyte supplementation may be a risk factor for gastric mucosal lesions, but relevant evidence is limited in horses. Investigate the effects of PO sodium chloride (NaCl) supplementation on the gastric mucosa of exercising horses. We hypothesized that NaCl supplementation would neither cause nor exacerbate existing gastric mucosal damage. Fifteen 3-year-old healthy Warmblood stallions from a stud farm. Placebo-controlled study with a crossover design. Horses were fed either a NaCl pellet at a dosage adequate to replace the electrolyte losses in 10 L sweat or a placebo for 19 days with a washout period of 14 days between treatments. The gastric mucosa was evaluated by gastroscopy before and after treatment. Blood samples were collected for evaluation of acid-base status, packed cell volume (PCV), and total protein, creatinine and blood urea nitrogen concentrations. Urine was collected, and urine specific gravity, electrolyte, creatinine, and urea concentrations were measured. The initial prevalence of gastric mucosal lesions was 85%. Sodium chloride pellets did not adversely affect the gastric mucosa and treatment did not significantly alter the hematologic and serum biochemical variables. Urine creatinine concentrations significantly decreased and urinary sodium concentrations significantly increased after supplementation with NaCl pellets. Water intake did not significantly differ between treatments. Daily NaCl pellet supplementation is a palatable and safe way to replace electrolyte losses from sweating in exercising horses and has no negative effects on the gastric mucosa.

Feeding spent hemp biomass to lactating dairy cows: Effects on performance, milk components and quality, blood parameters, and nitrogen metabolism

The legalization of industrial hemp by the 2018 Farm Bill in the United States has driven a sharp increase in its cultivation, including for cannabinoid extraction. Spent hemp biomass (SHB), produced from the extraction of cannabinoids, can potentially be used as feed for dairy cows; however, it is still illegal to do so in the United States, according to the US Food and Drug Administration Center for Veterinary Medicine, due to the presence of cannabinoids and the lack of data on the effect on animals. To assess the safety of this byproduct as feed for dairy cows, late-lactation Jersey cows (245 ± 37 d in milk; 483 ± 38 kg body weight; 10 multiparous and 8 primiparous) received a basal total mixed ration (TMR) diet plus 13% alfalfa pellet (CON) or 13% pelleted SHB for 4 wk (intervention period [IP]) followed by 4 wk of withdrawal period (WP), where all cows received only the basal TMR during WP. The dry matter intake (DMI), body weight, body condition score, milk yield, milk components, and fatty acid profile, blood parameters, N metabolism, methane emission, and activity were measured. Results indicated that feeding SHB decreased DMI mainly due to the low palatability of the SHB pellet, as the cows consumed only 7.4% of the total TMR with 13.0% SHB pellet offered in the ration. However, milk yield was not affected during the IP and was higher than CON during the WP, leading to higher milk yield/DMI. Milk components were not affected, except for a tendency in decreased fat percentage. Milk fat produced by cows fed SHB had a higher proportion of oleate and bacteria-derived fatty acids than CON. The activity of the cows was not affected, except for a shorter overall lying time in SHB versus CON cows during the IP. Blood parameters related to immune function were not affected. Compared with CON, cows fed SHB had a lower cholesterol concentration during the whole experiment and higher β-hydroxybutyric acid during the WP, while a likely low-grade inflammation during the IP was indicated by higher ceruloplasmin and reactive oxidative metabolites. Other parameters related to liver health and inflammatory response were unaffected, except for a tendency for higher activity of alkaline phosphatase during IP and a lower activity of gamma-glutamyl transferase during WP in the SHB group versus CON. The bilirubin concentration was increased in cows fed SHB, suggesting a possible decrease in the clearance ability of the liver. Digestibility of the dry matter and protein and methane emission were not affected by feeding SHB. The urea, purine derivatives, and creatinine concentration in urine was unaffected, but cows fed SHB had higher N use efficiency and lower urine volume. Altogether, our data revealed a relatively low palatability of SHB affecting DMI with minimal biological effects, except for a likely low-grade inflammation, a higher N use efficiency, and a possible decrease in liver clearance. Overall, the data support the use of SHB as a safe feed ingredient for lactating dairy cows.

Comparing dehulled hemp meal and canola meal as a protein supplement for lactating dairy cows

Effects of replacing canola meal with dehulled hemp meal in the diet of lactating dairy cows on the dry matter intake (DMI), milk production, milk fatty acid profile, blood metabolites, total-tract nutrient digestibility, and transfer of cannabinoids were determined in 12 lactating, nonpregnant Holstein cows. These cows were used in a 3 × 3 Latin square design with three 3-wk experimental periods consisting of 2 wk of adaptation and 1 wk of sampling. Cows received basal partial mixed rations supplemented with either 15% dry matter (DM) canola meal (CM15), 15% DM dehulled hemp meal (HM15), or 7.5% DM dehulled hemp meal and 7.5% DM canola meal (CM7.5HM7.5). Diets were formulated to be isoenergetic and isonitrogenous, but the HM15 and CM7.5HM7.5 diets contained, on average 1.2 percentage units more crude protein (CP) that the CM15 diet. The CP of the dehulled hemp meal contained less soluble protein than that of canola meal. Hence, the intake of soluble protein did not differ among diets. Canola meal contained less crude fat than hemp seed meal (3.46% vs. 8.25% DM). The lipid fraction of canola meal fat contained more oleic acid (C18:1 cis-9; 47.3 vs. 14.9 g/100 g of fatty acids, FA) and vaccenic acid (18:1 cis-11; 13.7 vs. 1.2 g/100 g of FA) and less linoleic acid (C18:2n-6; 21.9 vs. 55.7 g/100 g of FA) and α linolenic acid (C18:3n-3; 3.2 vs. 8.9 g/100 g of FA) than the lipid fraction of hemp seed meal. The hemp seed meal contained 4.9 µg/g cannabidiol, 5.1 µg/g cannabidiolic acid, and 0.1 µg/g tertahydroxycannabinolic acid A. Treatments did not differ in DMI, yields of milk, milk protein and milk fat, total-tract neutral detergent fiber digestibility, and blood plasma concentrations of β-hydroxybutyrate and nonesterified FA. Apparent total-tract DM digestibility was lowest in the HM15 treatment, whereas the CP digestibility and the concentrations of urea in blood, urine, and milk were lowest in the CM15 treatment. Cannabinoids were not detected in urine, milk, and blood plasma. Replacing canola meal with hemp seed meal increased milk fat contents of polyunsaturated fatty acids (PUFA), which were 3.42, 3.90, and 4.25 g/100 g of FA for the CM15, CM7.5HM7.5, and HM15 treatments, respectively. Especially, the milk fat contents of 18:2n-6 (1.99 vs. 1.56 g/100 g FA) and 18:3n-3 (0.31 vs. 0.43 g/100 g FA) were increased by hemp meal feeding. Especially, the milk fat contents of 18:2n-6 (1.99 vs. 1.56 g/100 g FA) and 18:3n-3 (0.31 vs. 0.43 g/100 g FA) were increased by hemp meal feeding. Our data show that hemp seed meal is a suitable and safe replacement for canola meal as a feed for lactating dairy cows and that this replacement increases CP digestibility and urea in urine, milk, and blood plasma, as well the PUFA content of milk fat.

Comparison of residual kidney function assessment between the hemodialysis two- and three-day interdialytic interval.

Background Residual kidney function (RKF) is a dynamic marker having been shown to demonstrate fluctuations over successive days of the interdialytic interval. This study compares measured RKF between the long (LIDP) and short interdialytic intervals (SIDP). Methods This was a prospective cohort study. Thirty-four clinically stable, ambulatory facility hemodialysis patients were recruited. Urine samples collected in the last twelve hours of each interdialytic interval were paired with a blood test at the conclusion of each twelve-hour interval to evaluate measured RKF through a mean of urinary urea and creatinine clearances. The paired Student's t-test and the Wilcoxon matched-pairs signed-ranks were used respectively to compare differences in assessed mean and median RKF. Results Although average serum creatinine (607 +/- 219 µmol/L vs. 547 +/- 192 µmol/L, p = <0.01) and serum urea concentrations (25 +/- 15 mmol/L vs. 19 +/- 5 mmol/L, p = 0.01) were higher in the LIDP compared to SIDP, there was no statistically significant difference in urine volume (630 +/- 460 mL vs. 520 +/- 470 mL, p = 0.06), urine urea (116 +/- 49mmol/L vs. 118 +/ 90, p = 0.87), or urine creatinine (7816 +/- 3943 µmol/L vs. 8926 +/- 5752 µmol/L, p = 0.06) concentrations. On the whole, there was no significant difference in assessed RKF between the long and short interdialytic intervals (mean 8 +/- 6 mL/min vs 6 +/- 4 mL/min, p = 0.24; median 6.3 [3.2 - 10.4] vs 5.8 [3.8 - 8.9], p = 0.13). Conclusions There was no statistically significant difference observed in assessed RKF between the LIDP and SIDP. Measured RKF through samples collected from the LDIP and SIDP are comparable.

Antiurolithiatic effect of a polyherbal formulation against sodium oxalate-induced urolithiasis in rats

BackgroundThe present study assesses the role of polyherbal formula (LACTN) against sodium oxalate (NaOx)—stimulated urolithiasis prophylactic and curative. Forty-eight rats were separated into the following regimen’s groups: Groups I, II, III, and IV (prophylactic groups). Group I (control group) received saline as vehicle. Group II (urolithiatic group) received 70 mg NaOx / kg b.wt, i.p. Groups III and IV received LACTN and cystone prophylactic (500 and 750 mg/kg b.wt, respectively) from 1st day to 7th day of urolithiasis induction. Groups V, VI, VII, and VIII (curative groups): these were divided into the prophylactic regimes, but LACTN and cystone were administered from 7th day to 14th day of urolithiasis induction.ResultsUrolithiatic rats co-/post-treated with LACTN and cystone elevated the urinary volume significantly (P < 0.05). Also, a significant decrease (P < 0.05) was observed in the serum and urine calcium and phosphate concentrations beside the increased magnesium value in urolithiatic rats co-/post-treated with LACTN. LACTN significantly (P < 0.05) ameliorates serum and urine creatinine, urea, and uric acid concentration. Moreover, urolithiatic rats co-/post-treated with LACTN significantly (P < 0.05) diminished MDA and increased GSH, GST, SOD, and CAT compared with urolithiatic rats.ConclusionsLACTN has anti-lithogenesis effect that may be due to its ability to remove the already presenting stone and/or to prevent the generation of extra calcium oxalate crystals. This action may be due to its components’ synergetic action that may provide encouraging combined formula to prevent/treat urolithiasis.

EVALUATION OF LACTATIONAL EXCRETION OF UREA AND AMMONIA IN DAIRY CATTLE HERDS

The aim of the study was to evaluate the lactational unit production of urea and ammonia emissions from cows kept in eastern Poland. The study covered 1089 lactations of Polish Holstein-Friesian cows born between 1992 and 2018 in 15 cattle herds located in the Mazovia and Podlasie voivodships. The amount of urea excreted in urine and nitrogen compounds in cow feces was calculated based on the following regression equations: (y = 15.46 urea concentration in milk (g/L) + 193.4); y = 11.42 urea concentration in milk (g/L) + 41.93); y = 4.05 urea concentration in milk (g/L) + 151.47). Several factors affecting the total production of urea were examined. Four groups of animals were distinguished according to their milk yield from a 305-day lactation (&lt;6000; 6001-8000; 8001-10000; &gt;10000 kg); three groups based on year of birth (1992-2000; 2001-2010; 2011-2018); four age groups (first lactation; second lactation; third lactation; fourth to twelfth lactation); and three groups according to urea content in milk (1-150; 151-250; &gt;250 mg/L). The results of the study showed that the average concentration of urea in cow urine was 78.6 kg and the ammonia emission from a lactating cow was 44.6 kg. The study demonstrated a large variation in the amount of nitrogen compounds excreted in feces and the degree of ammonia emission risk among animals. The main factors differentiating the amount of nitrogen compounds in urine and feces and the level of ammonia emission into the atmosphere included the cow's production level, year of birth, and urea content in milk.

Water balance and urinary parameters of lambs fed diets containing cactus cladodes varieties

AbstractThe water balance and urinary parameters of lambs fed diets containing cactus cladodes varieties were evaluated. Thirty-six uncastrated male Santa Inês lambs (22.0 ± 2.9 kg initial body weight) were distributed in a completely randomized design, with three treatments and 12 replicates. The animals were fed a control diet (Tifton-85 hay as exclusive roughage), Miúda or Orelha de Elefante Mexicana (OEM) cactus-based diets. Urine samples were collected 45 days after the introduction of the tested diets, and voluntary water intake was measured over 10 days, during the experimental period. Diets containing Miúda or OEM cactus caused a reduction of 68.35 and 77.03% in voluntary water intake, respectively. In addition, the Miúda cactus cladodes caused urinary alkalinization (pH = 8.14) and reduction in the urinary excretion index (UEI) and on the fractional excretion rate (FER) of total calcium (Ca). The diets with OEM cactus cladodes caused higher oxalates intake (6.21 g/day) and increase in urinary volume. Regardless of the variety, there was a reduction in the urinary concentrations of urea, creatinine, total proteins, Ca, phosphorus (P), UEI of urea and P, as well as in FER of P, compared to the control diet. Urinary Mg content and UEI of uric acid and Mg increased and FER of P decreased by diets supplemented with different varieties of cactus cladodes. In conclusion, the cactus cladodes increased water intake and retention, and diuresis in lambs, altered urine parameters, without compromising kidney function.

Effect of reduced dietary protein on productivity and plasma, urine, and milk metabolites in organic sows during winter conditions

Oversupply of protein is a challenge in organic sow production. Currently, organic sow feed is composed in accordance with feeding standards of conventional sows, which do not take the higher daily feed allowance and nutritional contribution from roughage into consideration. The objective of the current study was to investigate the effect of reduced dietary protein in gestational compound feed for organic outdoor sows during winter conditions, using metabolites in plasma, urine, and milk as indicators of sows’ metabolic status.In total, 20 sows (Topigs Norsvin; TN70) were included in the experiment, lasting from d30 of gestation until weaning at d49 of lactation under outdoor conditions during winter. During gestation, sows were fed one of two isoenergetic diets containing 88 g SID CP pr. kg DM (Control) and 72 g SID CP pr. kg DM (Low protein), corresponding to 16% and 31% below the current recommendation for indoor sows. In lactation, all sows were fed a standard diet containing 125 g SID CP pr. kg DM.Sow performance traits were not affected by dietary protein level during gestation. An interaction indicated that sows fed the control diet had 23% and 11% higher urinary urea concentrations at d60 and d100 of gestation, respectively, compared with the low protein diet. During lactation, the milk yield of sows fed low protein in gestation increased more than that of control sows (P < 0.05). Concurrently, the litter gain of the low protein sows was improved, and their litters were heavier at d49 compared to control sows (276 kg vs. 238 kg; P < 0.001).In conclusion, organic outdoor sows benefitted from reduced dietary protein during gestation in winter conditions, as indicated by urinary urea concentration, milk yield, and litter gain.

Sustainable recovery of plant essential Nitrogen and Phosphorus from human urine using industrial coal fly ash

Coal-based thermal power plants play a pivotal role in meeting global energy demand. The amount of fly ash generated from these plants increases every year, and its successful use has posed a significant environmental risk in the last decade. In this study, coal fly ash was packed in a fixed-bed adsorption column to remove Urea–N from synthetic human urine. To assess the efficacy of fly ash in the removal of Nitrogen, various process parameters were tested, including initial urea concentration in urine (20, 40, 60%), fly ash loading in column (100, 150, 200 g), and urine flow rate through the column (2, 4, 6 L h−1). The initial urea concentration and bed height were found to have a major impact on nutrient recovery. Following nitrogen removal, the effluent urine was de-phosphatized using struvite precipitation and approximately 83% of phosphorus was recovered. High inlet urine concentration (60%), high flow rate (6 L h−1) and minimal adsorbent loading (100 g) resulted in maximum struvite precipitation. The column breakthrough and characteristic parameters of four different models were predicted using kinetic modelling of the adsorption data, in which Yoon–Nelson and Thomas’ models suggested efficient removal and recovery of plant essential nutrients. Findings in this study suggests that the coal fly ash appears to be a promising adsorbent for extracting these important plant nutrients. The effect of initial urine concentration, fly ash loading in the column, and urine flow rate on dephospatisation was calculated. The findings of this study will shed light on the process of nutrient adsorption process selection and detail the comparative differences between continuous and batch nutrient recovery of human urine.

Lipid microspheres containing urea for slow release of non-protein N in ruminant diets

Context Urea is widely used in ruminant diets as a source of non-protein nitrogen (NPN), partially substituting for true protein in feed, but high levels of urea in the diet may cause toxicity. Aims This study investigated the microencapsulation of urea in carnauba wax for slow release in the rumen to improve the N efficiency and growth of sheep. Methods Two microencapsulated systems were developed with urea:carnauba wax ratios (w/w) of 1:2 (U12) and 1:4 (U14). Based on the initial characterisation, only U12 was examined in an in vivo experiment with Santa Ines crossbred male sheep (n = 40) initially weighing 28 ± 0.6 kg at 270 days of age. The experimental arrangement was a completely randomised design, and the animals were distributed into four treatments; i.e. four levels of inclusion (0, control; 15; 30; and 45 g/kg DM) of microencapsulated urea in the diet. Key results The dietary inclusion of microencapsulated urea was associated with linear increases (P ≤ 0.05) in the intake of DM and metabolisable energy, the digestibility of crude protein, non-fibrous carbohydrates and fibre fractions, and N balance. Additionally, liveweight gain and feed efficiency increased quadratically (P &lt; 0.001). There were also linear reductions (P &lt; 0.001) in blood urea and urinary urea concentrations. Conclusions The study demonstrated that the inclusion of up to 30 g/kg U12 microencapsulated urea can be recommended as a source of slow-release urea in sheep diets since it improved the performance and feed efficiency and promoted lower concentrations of blood urea and urinary urea. Implications The use of urea microencapsulated in carnauba wax can reduce the risk of urea toxicity and provide a safer way to supply NPN to ruminants and improve N utilisation.