Urine Collection Research Articles

Short-term effects of ambient PM1, PM2.5, and PM10 on internal metal/metalloid profiles in older adults: A distributed lag analysis in China

There is limited evidence linking exposure to ambient particulate matter (PM) with internal doses of metals and metalloids (metal(loid)s). This study aimed to evaluate the effects of short-term exposure to ambient PM on urine metal(loid)s among Chinese older adults. Biological monitoring data of 15 urine metal(loid)s collected in 3, 970 community-dwelling older adults in Fuyang city, Anhui Province, China, from July to September 2018, were utilized. PMs with an aerodynamic diameter ≤ 1 µm (PM1), ≤ 2.5 µm (PM2.5), and ≤ 10 µm (PM10) up to eight days before urine collection were estimated by space–time extremely randomized trees (STET) model. Residential greenness was reflected by Normalized Difference Vegetation Index (NDVI). We used generalized additive model (GAM) combined with distributed lag linear/non-linear models (DLMs/DLNMs) to estimate the associations between short-term PM exposure and urine metal(loid)s. The results suggested that the cumulative exposures to PM1, PM2.5, or PM10 over two days (lag0-1 days) before urine collection were associated with elevated urine metal(loid)s in DLMs, while exhibited linear or “inverted U-shaped” relationships with seven urine metal(loid)s in DLNMs, including Gallium (Ga), Arsenic (As), Aluminum (Al), Magnesium (Mg), Calcium (Ca), Uranium (U), and Barium (Ba). Aforementioned results indicated robust rather than spurious associations between PMs and these seven metal(loid)s. After standardizations for three PMs, PM1 was the greatest contributor to U, PM2.5 made the greatest contributions to Ga, As, Al, and Ba, and PM10 contributed the most to Mg and Ca. Furthermore, the effects of three PMs on urine Ga, As, Al, Mg, Ca, and Ba were reduced when exposed to higher levels of NDVI. Overall, short-term exposures to ambient PMs contribute to elevated urinary metal(loid) levels in older adults, and three PMs exhibit various contributions to different urine metal(loid)s. Moreover, residential greenness may attenuate the effects of PMs on urine metal(loid)s.

Estimation of 24-hour urinary sodium and potassium excretion among Chinese adults: a cross-sectional study from the China National Nutrition Survey

BackgroundHigh-sodium intake is one of the most important risk factors for hypertension and cardiovascular disease, yet reliable national estimates of sodium intake in Chinese adults have not been reported. ObjectivesWe estimated 24-h urinary sodium and potassium excretion and population daily sodium and potassium intake of Chinese adults for the first time at a national level. MethodsA nationally representative cross-sectional survey was conducted to collect 24-h urine specimens from Chinese adults aged ≥18 y as part of the China National Nutrition Survey 2015. Finally, 10,114 participants (4932 males and 5182 females) with complete 24-h urine specimens were included in the analysis. Estimates of mean urinary electrolyte excretion and demographic, socioeconomic, and health characteristics were used with weighted coefficients that accounted for sample selection probabilities, poststratification weighting, and nonresponse rates. ResultsThe estimation of overall weighted mean 24-h urinary sodium excretion was 4121 mg (95% confidence interval [CI]: 3993, 4250), 4155 mg (95% CI: 3993, 4317) in males and 4081 mg (95% CI: 3953, 4209) in females (P for sex difference = 0.36). Overall mean 24-h urinary potassium excretion was 1534 mg (95% CI: 1492, 1577), 1468 mg (95% CI: 1424, 1513) in males and 1614 mg (95% CI: 1569–1660) in females (P for sex difference <0.001). Mean 24-h urinary sodium excretion was significantly higher in rural adults (4350 mg; 95% CI: 4217, 4483) than in urban residents (3909 mg; 95% CI: 3739, 4080; P < 0.001), and in northern residents (4388 mg; 95% CI: 4237, 4539) than in southern residents (3998 mg; 95% CI: 3832, 4163; P = 0.002). ConclusionsThe first nationwide survey with 24-h urine collection confirmed that mean sodium intake in Chinese adults was more than twice the upper limit, whereas mean potassium intake was <60% of the lower limit, recommended by the World Health Organization. Urgent measures should be taken to reduce sodium intake and increase potassium intake in China.

Quantification of quercetin from red onion (Allium cepa L.) powder via high-performance liquid chromatography-ultraviolet (HPLC-UV) and its effect on hyperuricemia in male healthy Wistar albino rats.

Onions (Allium cepa L.) contain various flavonols, including quercetin, kaempferol, anthocyanin, luteolin, and myricetin. Quercetin in onions is considered the primary bioactive component. To assess the impact of quercetin on hyperuricemia in healthy Wistar albino rats, this study used high-performance liquid chromatography with ultraviolet (HPLC-UV) to identify and measure quercetin in onion powder. Twenty-four 160 ± 10 g, six wistar albino male rats in each group were kept: NC (control sample, no onion powder), OT1, OT2, and OT3, which contained 11.13, 14.84, and 18.61 g/100 g onion powder, respectively. The treatment lasted 28 days, during which the last 7 days were for urine, feces, and blood collection. The results showed a trend of decreasing levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin, total cholesterol, and low-density lipoprotein in rats fed OT1, OT2, and OT3 diets. Improvements were observed in feed, water, and nutrient intake, feed conversion ratio, feed efficiency ratio, nutrient digestibility, nitrogen balance, body weight, blood urea nitrogen, creatinine, and uric acid levels (p ≤ .05). In contrast, high-density lipoprotein, triglycerides, serum total protein, neutrophils, and lymphocytes did not change (p ≥ .05). White blood cells, red blood cell count, platelet count, hemoglobin, and monocytes showed an upward trend. Based on our calculations, we determined the optimal human dosage from the most effective amount of onion powder. By taking into account the ratio of human-to-rat surface area, we estimate that the equivalent human dose of onion is 181.04 grams with 204 mg of quercetin. Additionally, when factoring in the dry matter content, the recommended dose of onion is 29.19 grams with 220 mg of quercetin.

Effect of isotretinoin on CYP2D6 and CYP3A activity in patients with severe acne.

Previously, retinoids have decreased CYP2D6 mRNA expression in vitro and induced CYP3A4 in vitro and in vivo. This study aimed to determine whether isotretinoin administration changes CYP2D6 and CYP3A activities in patients with severe acne. Thirty-three patients (22 females and 11 males, 23.5 ± 6.0years old) expected to receive isotretinoin treatment completed the study. All participants were genotyped for CYP2D6 and CYP3A5. Participants received dextromethorphan (DM) 30 mg orally as a dual-probe substrate of CYP2D6 and CYP3A activity at two study timepoints: pre-isotretinoin treatment and with isotretinoin for at least 1week. The concentrations of isotretinoin, DM and their metabolites were measured in 2-h postdose plasma samples and in cumulative 0-4-h urine collections using liquid chromatography-mass spectrometry. In CYP2D6 extensive metabolizers, the urinary dextrorphan (DX)/DM metabolic ratio (MR) (CYP2D6 activity marker) was numerically, but not significantly, lower with isotretinoin administration compared to pre-isotretinoin (geometric mean ratio [GMR] [90% confidence interval (CI)] 0.78 [0.55, 1.11]). The urinary 3-hydroxymorphinan (3HM)/DX MR (CYP3A activity marker) was increased (GMR 1.18 [1.03, 1.35]) and the urinary DX-O-glucuronide/DX MR (proposed UGT2B marker) was increased (GMR 1.22 [1.06, 1.39]) with isotretinoin administration compared to pre-isotretinoin. Administration of isotretinoin did not significantly reduce CYP2D6 activity in extensive metabolizers, suggesting that the predicted downregulation of CYP2D6 based on in vitro data does not translate into humans. We observed a modest increase in CYP3A activity (predominantly CYP3A4) with isotretinoin treatment. The data also suggest that DX glucuronidation is increased following isotretinoin administration.

Effect of Supplementing a Bacillus Multi-Strain Probiotic to a Post-Weaning Diet on Nutrient Utilisation and Nitrogen Retention of Piglets

Probiotics are suggested to improve pig health, nutrient utilisation, performance, and they may reduce nitrogen (N) pollution. However, the effectivity of a single strain might be different from that of a multi-strain. The study was conducted to investigate the effect of a novel Bacillus multi-strain on nutrient digestibility, energy utilisation, and N retention in weaned piglets using an European diet. The experiment consisted of a control diet (CD) and a supplemented diet (SD). The probiotic used for SD consisted of B. amyloliquefaciens—516 and B. subtilis—541. A total of eight boars/treatment were weaned (day 0; 8.5 kg body weight). Only boars were used to ease the collection of urine. Until day 10, piglets were fed ad libitum and were housed in pairs; from day 11, piglets were fed semi ad libitum (feeding level 3.2× metabolic body weight) and were housed individually. From day 14, faecal and urine were collected twice daily. Piglets were humanely euthanised at day 19 (15.0 kg bodyweight) after which the jejunum, ileum, and colon content were collected. In faeces, the apparent total tract digestibility (ATTD) of, amongst others, DM, organic matter (OM), crude protein (CP), non-starch polysaccharides (NSP), and subsequently net energy (NE) were calculated using titanium dioxide as an indigestible marker. In the jejunum and ileum, the apparent digestibility of CP was estimated, and in the ileum, the apparent AA digestibility was measured. In urine, the N content was measured to determine N retention. The volatile fatty acid (VFA), branched-chain fatty acid (BCFA), and lactic acid content were analysed in the colon and faeces. The apparent CP digestibility in the jejunum and ileum was not affected by treatment (p &gt; 0.05), and no effect was observed on the apparent ileal digestibility of AA (p &gt; 0.05). Supplementation with the multi-strain probiotic improved the ATTD of DM (p = 0.01; +1.3%) and OM (p = 0.02; +1.2%) and tended to improve the ATTD of CP (p = 0.10; +2.2%) and NSP (p = 0.07; +1.9%). The multi-strain probiotic also improved the NE value (p = 0.02; +0.2 MJ/kg DM) and improved N retention (p = 0.05; +1.6%). Supplementation did not influence the VFA, BCFA, and lactic acid content in the faeces (p &gt; 0.05). However, in the colon, supplementation did influence the lactic acid content (lower; p = 0.01) and tended to influence the valeric acid content (higher; p = 0.09). In conclusion, results from the current study suggest that the multi-strain probiotic has the potential to contribute to improve nutrient efficiency in weaned piglets. More research needs to be conducted to identify the impact of the improved nutrient utilisation on gut health in post-weaned pigs as well as environmental pollution.

Dried blood spots for erythropoietin analysis: Detection of micro-doses, EPO c.577del variant and comparison with in-competition matching urine samples.

The abuse of recombinant erythropoietin (rEPO) and other erythropoietin (EPO) receptor agonists (ERAs) in sports prompted the need for sensitive detection methods of these substances. Dried blood spot (DBS) samples offer an easy solution for simultaneous collection of blood and urine during a doping control, but sensitivity issues are often presented as a challenge for routine EPO analysis from DBS. Its potential use for detecting rEPO micro-doses and the EPO gene c.577del variant thus needed further demonstration. Here, capillary blood collected from the arm skin of 111 athletes with Tasso-M20 (17.5μL/spot), collected during professional triathlon competitions, were analysed. Also, venous blood samples from healthy volunteers were used to prepare several spots of 20 μL on Mitra VAMS (from an rEPO micro-dose study) and Whatman filter paper (from an EPO gene variant study). Immunopurification of 2 spots with MAIIA EPO Purification Gel Kit and analysis with sodium N-lauroylsarcosinate polyacrylamide gel electrophoresis (SAR-PAGE)/Western blot resulted in sensitive detection of (1) micro-doses of rEPO from Mitra VAMS, (2) endogenous EPO from Tasso-M20 in all in-competition subjects, and (3) the EPO c.577del variant from Whatman filter paper. Additionally, in-competition endogenous EPO was detected in DBS even when matching urine samples had undetectable EPO. In conclusion, this work demonstrated that DBS can be a useful complementary matrix to urine samples for EPO detection.

Comparative analysis of Basiliximab and Alemtuzumab induction therapies in blood type A2-to-B kidney transplantation: Impact on kidney function and de novo donor-specific HLA antibodies

PurposeBlood group B kidney transplant candidates have lower transplantation rates and longer waiting times compared to other blood groups. Kidney transplantation from blood group A2-to-B has offered a solution for these patients. This study aimed to investigate the impact of Basiliximab and Alemtuzumab induction therapies on kidney function and de novo donor-specific antibodies (DSA) in blood type A2-to-B kidney transplant recipients within the first 12 months of post-transplant. MethodsA retrospective analysis was conducted on 110 consecutive A2-to-B kidney transplant recipients between January 2015 and December 2022. Of these, 46 (41.8%) received Basiliximab, while 64 (58.2%) received Alemtuzumab as induction therapy. Demographics and comorbidities data were collected and compared between the two groups. Serum samples collected at 4- and 12-month intervals post-transplant were used to assess the presence of de novo DSA. Kidney allograft function was evaluated by monitoring serum creatinine levels and assessing Creatinine Clearance based on 24-h urine collection at various time points. ResultsDuring the follow-up period, 20.00% of patients who received Alemtuzumab developed de novo DSA, whereas none of the patients induced with Basiliximab developed de novo DSA (p = 0.038). Recipients who received Basiliximab were older (mean age = 72.00) and received higher Kidney Donor Profile Index (KDPI) kidneys (mean = 75) compared to those induced with Alemtuzumab (mean age = 58.00, mean KDPI = 49) (p < 0.001), with no significant difference observed in the last follow-up creatinine clearance or creatinine levels between the two groups (p = 0.28). ConclusionThe use of Basiliximab as induction immunosuppression in A2-to-B kidney transplant recipients is associated with a lower incidence of de novo HLA DSA formation without significant differences in overall renal function compared to Alemtuzumab.

Net energy content of hybrid rye fed to growing pigs and effects of particle size on energy values

An experiment was conducted to determine the digestible energy (DE), metabolizable energy (ME), and net energy (NE) contents of hybrid rye fed to growing pigs using indirect calorimetry and to investigate the effects of particle size on energy values. Thirty growing barrows (18.06 ± 0.83 kg initial body weight) were individually housed in metabolism crates and randomly allotted to one of five dietary treatments to give six replicates per treatment. Two hybrid rye varieties (Bono and Gatano) were ground in a hammermill mounted with a 4.0-mm or 3.2-mm screen to obtain coarse and fine particle size, respectively. Dietary treatments included a corn-soybean meal basal diet and four additional diets containing 300 g/kg of the test ingredients in a 2 × 2 factorial based on hybrid rye variety (Bono or Gatano) and particle size (Coarse or Fine). Pigs were fed experimental diets for 15 days, including 10 days for adaptation and 5 days for total fecal and urine collection to determine the DE and ME of the experimental diets. Pigs were then moved into indirect calorimetry chambers to determine 24-h heat production and 12-h fasting heat production. All data were analyzed using the MIXED procedure of SAS with the individual pig as the experimental unit. The geometric mean diameter (Dgw) for coarsely versus finely ground Bono and Gatano were 1111 versus 594 µm and 1210 versus 717 µm, respectively. The coefficient of apparent total tract digestibility (CATTD) of dry matter (DM) and gross energy (GE) were greater (P < 0.05) in diets containing finely than coarsely ground hybrid rye. The DE and ME of finely ground hybrid rye were greater (P < 0.05) than those of coarsely ground hybrid rye, and the NE of finely ground hybrid rye tended to be greater (P = 0.084) than that of coarsely ground hybrid rye. No differences were observed for the DE, ME, and NE contents between Bono and Gatano. The determined NE for coarsely and finely ground Bono were 11.06 and 11.77 MJ/kg DM, and the respective NE values for coarsely and finely ground Gatano were 11.09 and 11.57 MJ/kg DM. In conclusion, the energy values of different hybrid rye varieties might be comparable. Particle size reduction could significantly improve the DE and ME values of hybrid rye fed to growing pigs, while the NE value was only numerically improved.

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.

211 Evaluation of Beef Heifer Variability in the Ability to Eat and Digest a High Forage Diet

Abstract This study evaluated beef heifers selected for high or low digestible fiber intake (DFI) and investigated its relationship with methane production, residual feed intake (RFI), and total tract digestibility. Sixteen recently weaned black Angus beef heifers (n = 8/treatment) were selected from a group 64 heifers (224 ± 17.2 kg) fed a high forage-based diet [70% barley silage:30% pelleted concentrate (DM basis)]. The 64 heifers were fed in 6 outdoor pens equipped with GrowSafe bunks to monitor feed intake for 60 d (14 d adaptation + 46 d for data collection). Individual fecal samples and BW, and feed samples were taken once weekly. Fecal samples were pooled by animal. Feed and fecal samples were analyzed for dry matter (DM), neutral detergent fibre (NDF), and undigested neutral detergent fiber (uNDF) content. The internal marker uNDF was used to estimate total tract diet DM and NDF digestibility. The 8 heifers with the greatest and the 8 with the least digestible NDF intake (g/kg BW0.75) were selected and used for methane measurements using the GreenFeed system (42 d) and in a total-tract digestibility trial with total fecal and urine collection using the same high forage based diet. Results from the GrowSafe selection trial indicated no differences between the average BW of low and high DFI heifers (264 vs. 274 kg, P = 0.20). Heifers selected for high DFI had greater (P &amp;lt; 0.01) DM and NDF intake (kg/d or % of BW), and digestibility (49.6 vs. 42.1% NDF digestibility). The heifer groups differed in RFI (P &amp;lt; 0.01), with high DFI categorized as inefficient (+0.84 RFI) and low DFI as efficient (-0.34 RFI). No differences in ADG were observed between low and high DFI heifers during this short 46 d study period (0.614 vs 0.773, P = 0.16). High DFI heifers had lower methane production than low DFI heifers (15.9 vs. 19.0 g/kg of DMI, P = 0.02). The results of the total-tract digestibility trial showed that the high DFI heifers had a greater DMI compared with the low DFI heifers (10.9 vs. 10.2 kg/d; P = 0.04). The DMI intake was not different between groups when expressed as a % of BW (2.06 vs 2.04, P = 0.65). There was also no difference observed for DM digestibility (73.0 vs 73.1%) between the two groups. It is important to note that in the digestibility study, the DMI was less than in the GrowSafe selection trial (2.5 vs 3.2% BW) and this may have influenced results. Heifers with high DFI were heavier than low DFI heifers (533 vs. 505, P = 0.02) during the digestibility trial. Results suggest that selecting heifers for high DFI may increase growth rate and reduce methane production.

PSXIII-3 Trace Mineral Source Matters to Reduce Trace Mineral Excretion and Maximize Mineral Retention in Growing Pigs

Abstract The study objective was to determine differences between a methionine hydroxy analog chelated trace mineral blend [MHAC; MINTREX Trace Minerals (Novus International Inc., St. Charles, MO)] and sulfate (inorganic) sources of trace minerals (ITM) on the apparent total tract digestibility (ATTD) of dry matter (DM) and mineral utilization in growing pigs. A total of 10 growing gilts (PIC North America, Hendersonville, TN) weighing 50.5 ± 2.6 kg were randomly assigned to either an MHAC or an ITM dietary treatment. Supplemental Zn, Cu, and Mn levels for both treatments were 100, 20, and 40 mg/kg, respectively. Diets were corn-soy-based with phytase added to release 0.09% standardized total tract digestible P. Pigs were housed in metabolism crates for 7-d, including 5 for adaptation and 2 for total fecal and urine collection. Data were analyzed using the MIXED procedure of SAS. Results showed that pigs fed MHAC had a numerical increase in the ATTD of DM compared with ITM (90.9 vs. 89.4%; P = 0.180). Pigs fed MHAC had greater ATTD of Zn than those fed ITM (36.4 vs. 16.8%; P = 0.013), greater Zn retention (87.1 vs. 36.9 mg/d; P = 0.011), and decreased Zn excretion than those fed ITM (159.1 vs. 209.3 mg/d; P = 0.013). Pigs fed MHAC had increased Zn retention:intake compared with ITM (0.353 vs. 0.152; P = 0.014). There was a numerical increase in Zn retention:absorption in pigs fed MHAC compared with ITM (0.977 vs. 0.796; P = 0.128). Pigs fed MHAC had greater ATTD of Cu than those fed ITM (52.5 vs. 30.7%; P = 0.012), had increased Cu retention (25.6 vs. 14.4 mg/d; P = 0.012) and less Cu excretion than those fed ITM (24.1 vs. 35.3 mg/d; P = 0.016). Pigs fed MHAC had increased Cu retention:intake compared with ITM (0.513 vs. 0.293; P = 0.017) and tended to increase Cu retention: absorption (0.980 vs. 0.944; P = 0.057). Pigs fed MHAC had greater ATTD of Mn than ITM (35.8 vs. 14.5%; P = 0.019), had increased Mn retention (42.4 vs. 16.5mg/d; P = 0.017), and less Mn excretion than ITM (77.2 vs. 103.0mg/d; P = 0.017). Pigs fed MHAC had increased Mn retention:intake compared with ITM (0.353 vs. 0.141; P = 0.018). There were no differences between MHAC and ITM in Mn retention:absorption (0.986 vs. 0.986; P = 0.993). Pigs fed MHAC had a numerical increase in the ATTD of P (69.3 vs. 62.9%; P = 0.373), numerically less P excretion (2.94 vs. 3.57g/d; P = 0.348), and numerically greater P retention (6.44 vs. 5.80; P = 0.376) than those fed ITM. In conclusion, pigs fed MHAC had greater Zn, Cu, and Mn availability than ITM. This is likely due to the distribution and utilization of these trace minerals where they are needed. Furthermore, MHAC decreased the excretion of these minerals to nourish the pigs and reduce their impact on the environment through nutrient losses.

PSXI-16 Nitrogen Excretion and Urine Ph in Growing Pigs Decreased By Reducing Dietary Protein Concentrations

Abstract The objective of the present work was to determine effects of reducing dietary crude protein (CP) concentrations with indispensable amino acid (AA) supplementation on nitrogen balance and urinary pH in growing pigs. Three experiments were conducted using 12 barrows with an initial body weight of 29.9, 50.2, and 78.2 kg (standard deviation = 1.8, 2.2, and 3.7, respectively) individually housed in metabolism crates. In each experiment, a quadruplicated 3 × 2 incomplete Latin square design with 3 diets varying CP concentrations in each experiment and 2 periods per square was employed. In experiments 1 and 2, experimental diets based on corn, soybean meal, corn distillers dried grain with solubles, and rapeseed meal were formulated to contain 16.8, 15.0, and 13.2% CP as-fed basis and 16.8, 14.9, and 13.1% CP as-fed basis, respectively. In experiment 3, experimental diets based on corn and soybean meal were formulated to contain 15.1, 13.2, and 11.4% CP as-fed basis. All diets were supplemented with indispensable AA to meet all indispensable AA requirements. Each period consisted of a 5-day adaptation period followed by a 4-day collection period. On days 6 and 10, chromic oxide was added at 0.5% in morning meals as a marker and the marker-to-marker procedure was used for the quantitative collection of feces. Urine collection was initiated at 10:00 on day 6 and terminated at 10:00 on day 10. Polynomial contrasts were performed to test linear and quadratic effects of dietary CP concentrations on the response variables in each experiment. In all experiments, daily N intake was linearly decreased (P &amp;lt; 0.05) with decreasing dietary CP concentrations. Decreasing dietary CP concentrations resulted in linear reduction in daily fecal N excretion (P &amp;lt; 0.05) in experiment 2 and linear reductions in daily urinary N excretion (P &amp;lt; 0.05) in all experiments. Total N excretion linearly decreased (P &amp;lt; 0.05) with decreasing dietary CP concentration in all experiments. The urinary pH obtained from 30- and 50-kg pigs was linearly decreased (P &amp;lt; 0.05) with decreasing dietary CP concentrations. In conclusion, lowering dietary CP concentrations decreased N excretion and urinary pH in 30-, 50-, and 78-kg pigs.

PSXI-17 Prediction Models for Phosphorus Excretion of Pigs

Abstract The objective of the present study was to develop prediction equations for daily phosphorus excretion based on body weight (BW) and dietary phosphorus concentration of pigs. Four experiments were conducted using pigs with an initial body weight of 15 kg, 30 kg, 50 kg, and 78 kg. In the experiment 1, the experimental diets were mainly based on corn, soybean meal, whey powder, fish meal, and blood plasma. In the experiments 2, 3, and 4, the diets based on corn, soybean meal, and fibrous ingredients were formulated. All experimental diets were supplemented with commercial phytase at 500 FTU/kg. In all experiments, a total collection method and the marker-to-marker procedure were used for fecal and urinary collection. Fecal and urinary phosphorus excretions were determined. Correlation coefficients among BW, daily phosphorus intake, and daily phosphorus excretion of pigs were determined. Prediction equations for phosphorus excretion were developed using BW and dietary phosphorus concentration as independent variables. The BW had positive correlations with fecal and total phosphorus excretion (r = 0.78 and P &amp;lt; 0.001 for fecal phosphorus excretion and r = 0.78 and P &amp;lt; 0.001 for total phosphorus excretion). The prediction equations for predicting fecal phosphorus excretion and total phosphorus excretion were: fecal phosphorus excretion (g·pig–1·d–1) = –0.647 – 0.00065 × BW2 + 0.270 × BW × dietary phosphorus concentration (R2 = 0.81; P &amp;lt; 0.001); total phosphorus excretion (g·pig–1·d–1) = –0.619 – 0.00064 × BW2 + 0.277 × BW × dietary phosphorus concentration (R2 = 0.85; P &amp;lt; 0.001) where BW in kg and phosphorus concentration in %. The BW of pigs corresponding to the age was predicted using the NRC model. The mean phosphorus excretion of pigs weighing from 7 kg to 120 kg at day 22 to 180 was calculated using a developed estimation equation, with BW and total phosphorus requirement used as independent variables. Daily fecal and total phosphorus excretions were 3.77 g·pig–1·d–1 and 4.01 g·pig–1·d–1, respectively.

PSXIII-15 Use of Creatinine as a Marker to Estimate Urine Output in Beef Cattle Fed a Finishing Or Backgrounding Diet

Abstract Unlike for high forage diets, there has been limited validation of spot urine sampling and the use of urinary creatinine as a marker to estimate urine output in beef cattle fed high grain diets. Therefore, the objective of this study was to validate the use of creatinine as a marker for estimating urine output in cattle fed a finishing (FIN) compared with a backgrounding (BKGN) diet. Six heifers were randomly allocated to 2 treatments in a crossover design with 21 d periods. Dietary treatments were alfalfa silage at 12% (FIN) or 60% (backgrounding; BKGN) of dietary dry matter (DM), with the remainder of the diet consisting of corn grain (67.8 or 38.1% on a DM basis), corn dried distillers grains with solubles (DDGS; 0.75 or 19.0%) and a constant level (1.15%) of supplement. Total collection (TC) of urine was conducted during the last 3 d of each period. Twelve spot urine samples were also collected during TC to represent every 2-h sampling in a 24-h cycle. Data were analyzed using SAS. Creatinine excretion rate varied from 27.2 to 35.0 with an average of 31.3 mg/kg of body weight per day. The creatinine concentration of spot samples collected for each heifer were averaged to simulate urine samples obtained from various spot sampling frequencies [equally spaced 12, 6, 4, and 2 time points (TP) starting at feeding: 12TP, 6TP, 4TP, and 2TP, respectively]. There was diurnal variation in the urinary creatinine concentration on both diets. Although creatinine concentration did not differ (P = 0.82) between 12TP and TC, use of 12TP underestimated (P &amp;lt; 0.01) urine output (11.2 vs. 18.0 kg/d). However, there was no diet effect (P ≥ 0.32) on creatinine concentration and total urine output across methods (12TP vs. TC). When comparing spot sampling TP, there was no diet, method, or diet × method interaction (P ≥ 0.28) on urinary creatinine concentration and urine output. The regression between TC and 12TP had an intercept different from 0, and slope differed from 0 and 1. As for TC and 6TP, the intercept was not different from 0; however, slope was different from 0 and 1. As expected, increasing the frequency of spot sampling improved precision and accuracy of the regression between the estimated and measured urine output according to adjusted R2 (0.27, 0.24, 0.87 and 0.92 for 2TP, 4TP, 6TP, and 12TP, respectively) and root mean square prediction error (8.95, 9.09, 3.75, and 2.94). In summary, the use of the spot sampling technique and urinary creatinine as a marker to estimate urine output in beef cattle fed either FIN or BKGN diets might not be reliable due to the diurnal variation in creatinine excretion and variable creatinine coefficients.

333 Using Specific Bacillus Strains to Improve Digestibility and Performance of Growing Steers

Abstract Low fiber digestibility is an important factor restricting the growth performance of cattle in the dry tropics, both during the initial growth phase in grazing systems and later during finishing in high-starch diets. Due to concerns relating to the non-therapeutic use of antibiotics, including ionophores, there is interest in replacing these with probiotics. The objective was to evaluate the effects of specific strains of Bacillus spp. (Bovacillus, Chr. Hansen, Denmark) on intake and total tract nutrient digestibility of two diets. The first diet was forage based [100% Rhodes grass hay with 69% neutral detergent fiber (NDF)], the second was a high-energy diet (20% Rhodes grass hay, 40% finisher pellet, 30% peanut hull fiber pellet, 10% ground barley, 47% NDF, 18% starch). Twelve Bos indicus steers (267 ± 7.5 kg) were blocked by initial body weight and randomly assigned to receive the diets either without probiotic supplementation (n = 6, Control) or the diets plus 3 g per head of a probiotic containing a mixture of Bacillus licheniformis and Bacillus subtilis (3.2 x 109 CFU/g) for the duration of the trial. Each diet was fed for a 34-d period in individual pens followed by a 7-d sampling period during which the steers were housed in metabolism crates for total collection of urine and feces. On the high-fiber diet, supplementing with the probiotic increased organic matter digestibility by 7.8% (49.9 vs. 53.8%) and NDF digestibility by 8.4% (49.7 vs. 53.9%) resulting in greater (P &amp;lt; 0.05) digestible fiber intake (1.62 vs. 1.72 kg/d). There was no effect of probiotic supplementation on intake or digestibility in the high starch diet, and Bacillus supplements did not change rumen microbial protein synthesis in both diets. In conclusion, supplementing steers with a Bacillus-based probiotic has the potential to improve the nutrient digestibility and performance of beef steers, especially in tropical grazing systems.

268 Copper Methionine Hydroxy Analogue Chelate in a Reduce and Replace Copper Strategy Improves Nutrient Availability in Growing Pigs

Abstract Research has shown that methionine hydroxy analogue chelated minerals [MHAC; MINTREX Trace Minerals (Novus International Inc., St. Charles, MO)] are more available than inorganic trace minerals. In growing pigs, 50 mg/kg of Cu as Cu-MHAC has been shown to reduce feed conversion compared with feeding 125 mg/kg Cu as CuSO4 and 150 mg/kg Cu as tri-basic copper chloride (TBCC). A metabolism study was conducted using 2 groups of 10 barrows (average BW of 33.2 + 3.03 kg) fed either 50 mg/kg Cu as Cu-MHAC or 150 mg/kg Cu as TBCC. There was a 14-d acclimation period followed by 3-d of total fecal and 5-d of total urine collection. Corn-soybean meal diets with 15% distillers dried grains and &amp;lt; 1% fat as soy oil were formulated to 0.98% SID lysine with 0.65% Ca and 0.49% P. Phytase was included at 1,500 FTU/kg. A common basal trace mineral premix supplying 120 mg/kg Zn, 10 mg/kg Cu and 20 mg/kg Mn in the SO4 form was used. Diets were provided in meal form twice daily at 5% of body weight per day. The total trial period was 21-d with BW measured at d 0 and 21. Feed disappearance was recorded throughout. Data were analyzed using the PROC MIXED procedure of SAS with treatment and initial BW as fixed effects and group as a random effect. Pigs fed Cu-MHAC gained 816 g/d compared with 787 g/d for those fed TBCC (P = 0.55). Feed conversion was 2.07 for TBCC pigs and 1.98 for Cu-MHAC pigs (P = 0.48). Dry matter digestibility was 90.9% and 89.9% (P = 0.18) for Cu-MHAC and TBCC pigs respectively. Dry matter fecal output was 9% less for Cu-MHAC pigs (P = 0.24). Cu retention percent was not different between Cu sources (64.4% Cu-MHAC vs 62.4% TBCC; P = 0.63). Cu excretion was less for Cu-MHAC pigs (41.3 mg/d Cu-MHAC vs. 103.9 mg/d TBCC; P &amp;lt; 0.001) as a result of reduced Cu intake. Cu-MHAC increased Zn (P &amp;lt; 0.05) and Mn (P &amp;lt; 0.01) retention by 8.9 and 11.1 percentage points, respectively. Iron absorption (P = 0.86) and retention (P = 0.81) were not affected by Cu source. Calcium absorption and retention were 3.8 percentage points greater (P = 0.12) for Cu-MHAC pigs. Absorption and retention of P was 3.4% (P = 0.25) and 2.7% greater (P = 0.49) for pigs fed Cu-MHAC. Cu-MHAC resulted in 1.9% greater N absorption (P = 0.06) and 8.7% greater N retention (P = 0.06%) than when 150 mg/kg Cu in the TBCC form was fed. These results indicate a reduce and replace Cu strategy with Cu-MHAC can reduce Cu excretion by 60% and improved overall mineral and N retention with the exception of Fe. These nutrient availability improvements may contribute to the improved feed conversion observed in performance trials with Cu-MHAC vs inorganic sources.

215 Optimizing the Standardized Ileal Digestible Lys-To-Net Energy Ratio for Nitrogen Utilization of Sows Throughout a 24-Day Lactation Period

Abstract Fifty multiparous sows (average parity 3.7±0.9 and initial BW 245.6±32.5 kg) were used to evaluate the effects of dietary standardized ileal digestible (SID) Lys-to-net energy (NE) ratios on nitrogen utilization throughout a 24-day lactation period. Sows were randomly assigned to one of five isoenergetic feeding programs that provided equally spaced and increasing Lys-to-NE ratios between 2.79 and 5.50 g SID Lys/Mcal NE. The feeding programs were generated by blending the two extreme diets in varying proportions using a precision feeding system and were provided to sows immediately after farrowing (d1) and until weaning at d 24 ± 1. At farrowing, litters were standardized to 12 piglets. Three nitrogen balances were conducted from d 4 to 7±1 (NB1), 12 to 15 ± 1 (NB2), and 20 to 23 ± 1 (NB3) using total urine collection and fecal grab sampling. Contrast statements were used to determine linear and quadratic effects of increasing Lys-to-NE ratios. Linear (LBL) and quadratic (QBL) broken-line and polynomial quadratic (QPM) models were used to determine the optimum dietary Lys-to-NE ratios for N retention. The Bayesian information criterion was used to assess best fit. Feeding program did not influence sow ADFI (5.96 ± 0.19 kg/d), BW change (-5.4 ± 4.1 kg) or change in backfat thickness (-2.0 ± 1.1 mm) over the entire 24-d lactation period, but piglet ADG increased with dietary Lys-to-NE ratio (linear; P &amp;lt; 0.05). Sow N intake increased with dietary Lys-to-NE ratio in NB2 and NB3 (linear; P&amp;lt; 0.001). Nitrogen retention (N intake – N output in urine and feces) increased with dietary Lys-to-NE ratio in all NB (linear; P = 0.05, P &amp;lt; 0.001, and P &amp;lt; 0.001 for NB1 -to 3, respectively). The QPM showed an inflection point at 3.75 g Lys/Mcal NE during NB1 and the QBL model showed break points at 2.87 and 4.83 g Lys/Mcal NE in NB2 and NB3, respectively. Nitrogen retention in milk increased with dietary Lys-to-NE ratio only in NB1 (linear; P &amp;lt; 0.05) and the QPM showed inflection points at 4.31, 4.37, and 4.90 g Lys/Mcal NE for NB1-to-3, respectively. Maternal nitrogen retention (N intake – N output in urine, feces, and milk) decreased and then increased in NB1 (quadratic; P &amp;lt; 0.01) and increased in NB2 and NB3 (linear; P &amp;lt; 0.01) with dietary Lys-to-NE ratio. The QPM showed inflection points at 4.01 and 3.01 g Lys/Mcal NE for NB1 and NB2, respectively, and the QBL model showed a breakpoint at 4.83 g Lys/Mcal NE for NB3. To optimize N retention, feeding programs with a Lys-to-NE ratio between 3.75 and 4.31, 2.87 and 4.37, and 4.83 and 4.90 g SID Lys/Mcal NE should be considered during early, mid, and peak lactation, respectively. Therefore, precision feeding programs can be developed to match the ideal SID Lys-to-NE ratio more closely at different stages of lactation to improve sow performance and reduce nitrogen excretion to the environment.

Study of Sequence of Histopathological Changes in Hyperglycaemia-Induced Experimental Diabetic Nephropathy in Wistar Rat Model

The sequence of histopathological changes in hyperglycaemia-induced nephrotoxicity as well as alteration in renal parameters is still not well established in diabetic models. Hyperglycaemic ambience has been shown to generate oxidative stress which becomes a trigger for further degenerative changes that occur in the microenvironment of the kidney. This study was therefore intended to investigate histopathological alterations in vascular, glomerular and tubulointerstitial compartments of the renal tissues, and the corresponding changes in values of oxidative stress markers, creatinine clearance, proteinuria and serum creatinine concentration in a duration of three, seven and twelve weeks of sustained hyperglycaemia in diabetic. The experiment included four groups of adult Wistar rat, Group A (Normal Control, treated with normal saline), Groups B, C and D were induced with diabetes (treated with 65mg/kg body weight of streptozotocin) and allowed for 3 weeks 7 weeks and 12 weeks respectively. At termination, Oxidative stress markers were analyzed using Oxidative stress marker kits. A 24 hours urine collection was obtained from metabolic cages few hours before sacrifice and used for renal analysis and histopathological examination was done using a light microscope. Results reveals that oxidative stress was climaxed at 7th week and was maintained at a constant level while histopathological changes in glomerulus first presented on the 3rd week accompanied by vascular changes. Tubulointerstitial changes were noticed on the 7th week. On the 12th week renal parameters were significantly altered when compared to the animals sacrificed on 3th and 7th week. In conclusion, the sequence in diabetic–induced renal dysfunction begins with changes in vascular and glomerular compartment followed by distortion in tubulointerstitial compartment. An alteration in renal parameters presents lastly and correlates with the histopathological changes. These findings can be adopted in clinical management and treatment of diabetes-induced kidney dysfunction. J. Bio-Sci. 31(1): 29-37, 2023

Urinary cortisol and cardiovascular events in women vs. men: The multi-ethnic study of atherosclerosis

Research suggests that women experience greater cardiovascular ischemic effects from stress than men. Visceral adiposity is an endocrine tissue that differs by sex and interacts with stress hormones. We hypothesized that urinary cortisol would be associated with increased cardiovascular events and change in coronary artery calcium score (CAC) in women, and these relationships would vary by central obesity. In the Multi-Ethnic Study of Atherosclerosis Stress Ancillary study, cortisol was quantified by 12-h overnight urine collection. Central obesity was estimated by waist-hip ratio (WHR). Multivariable Cox models estimated the relationship between cortisol and cardiovascular events and assessed for moderation by WHR. The relationship between cortisol and change in CAC Agatston score was assessed by Tobit regression models. 918 patients were analyzed with median follow up of 11 years. There was no association between urinary cortisol and cardiovascular events in the cohort. However, in individuals with below median WHR, higher urinary cortisol levels (upper tertile) were associated with higher cardiovascular event rates in the full cohort, women, and men, but not in groups with above median WHR. There was significant moderation by WHR in women, but not men, whereby the association between elevated cortisol and increased cardiovascular events diminished as WHR increased. Urinary cortisol was associated with increased change in CAC in women (P = 0.003) but not men, without moderation by WHR. Our study highlights associations between cortisol and subclinical atherosclerosis in women, and moderation of the relationship between cortisol and cardiovascular events by central obesity in both genders.

Glomerular hyperfiltration in patients with severe trauma

Background and objectiveAugmented renal clearance or glomerular hyperfiltration (GHF) can significantly affect the clinical outcomes of renally eliminated drugs by promoting subtherapeutic drug exposure. The aggression suffered in patients who suffer severe trauma is a predisposition to manifest GHF and the identification of these patients remains a clinical challenge. The main objective of this study was to describe the prevalence of GHF in a cohort of critically ill trauma patients. Materials and methodsProspective observational study of a cohort of adult patients admitted after suffering severe trauma or polytrauma in the Anesthesiology ICU of the University Hospital of Albacete (Spain). Creatinine clearance (ClCr) was calculated in a 4-h urine collection sample at 24, 72 and 168 h after admission applying the formula; CrCl: [Diuresis in ml (urine/4 h) × Creatinine in urine (mg/dl)] ÷ [240 (minutes) × Creatinine in plasma (mg/dl)]. A CrCl above 130 mL/min was considered GHF. The analyses were performed with the statistical software R version 4.0.4. Results85 patients were included. The median age of the patients was 51 years (IQR 26), 78.82% male. 68 patients were male (78.82%). 75.29% of the patients were polytraumatized. 61 patients (71.76%) presented GHF at some point in the CrCl determination. At 24 h of admission, 56.34% of the patients presented GHF with a mean CrCl of 195.8 ml/min, 61.11% of the patients presented it at 72 h with a mean CrCl of /min and 56.52% presented GHF at 168 h of admission with a mean CrCl of 207 ml/min. A significant positive relationship (p = 0.07) was found between GHF manifested at 72 h and at 168 h. We observed a statistically significant relationship between this phenomenon with younger ages, lower ISS scores and lower plasma creatinines. ConclusionsGHF are a common condition in critically ill patients admitted for severe trauma. We recommend the use of CrCl to assess renal function and make dosage adjustments. Studies are required to understand the clinical impact of these phenomena on drug elimination and to be able to establish the ideal dosage in those cases.