Use of a three-blood-sample plasma clearance technique to measure GFR in horses

Measurement of renal function in horses poses a particular challenge because plasma creatinine is influenced by muscle mass which is highly developed and variable between individuals, while conventional clearance methods involve potentially daunting problems, particularly urine collection and bladder washout. This paper provides data which enable technetium-diethyleneaminopentacetic acid (Tc-DTPA) clearance to be used to calculate glomerular filtration rate (GFR)/extracellular fluid volume (ECFV) as an expression of GFR in horses, as previously validated in humans, dogs and calves. Apart from being arguably a more physiological expression of GFR than using derivatives of body weight, the use of GFR/ECFV eliminates a source of delay and error, namely measurement of the injected dose, and offers the convenience of requiring only three blood samples. It therefore has advantages for both research and clinical applications.     

Histopathologic changes of the ear in canine models of mucopolysaccharidosis types I and VII

Mucopolysaccharidosis (MPS) types I and VII are inborn errors of metabolism caused by mutation of enzymes involved in glycosaminoglycan catabolism, which leads to intralysosomal accumulation of glycosaminoglycans. In children, severe forms of MPS I and VII are characterized by somatic and neurologic manifestations, including a poorly understood hearing loss. The purpose of this study is to describe the age-related histopathologic changes of the ear in spontaneous canine models of MPS I and VII. Pathologic changes in the ear were assessed in MPS I and VII dogs ranging from 1.6 to 9.3 months of age. Paraffin-embedded sections of the whole ear and Epon-embedded semithin sections of the cochlea were examined. The following lesions were blindly scored in the middle and inner ear: inflammation, cells vacuolization, thickening of osseous and membranous structures, perivascular vacuolated macrophages infiltration, and bone resorption. All dogs had lysosomal storage within cells of tympanic membrane, ossicles, tympanic bone and mucosa, cochlear bone, spiral ligament, limbus, and stria vascularis. The MPS I dogs mainly had progressive cochlear lesions. The MPS VII dogs had severe and early middle ear lesions, including chronic otitis media and bone resorption. The MPS I dog only partially recapitulates the pathology seen in humans; specifically, the dog model lacks inflammatory middle ear disease. In contrast, the MPS VII dog has severe inflammatory middle ear disease similar to that reported in the human. In conclusion, the canine MPS VII model appears to be a good model to study MPS VII-related deafness.     

青贮紫花苜蓿对奶牛生产性能、尿素氮和血液生化指标的影响

在苜蓿（Medicago sativa）中添加5%的糖蜜,并进行苜蓿大窖青贮和饲喂试验,研究以青贮苜蓿（试验组）替代相同干物质量（DM）的苜蓿干草（对照组）对奶牛生产性能、尿素氮及血液生化指标的影响。结果表明,给奶牛饲喂苜蓿青贮饲料有利于提高奶牛干物质采食量（Dry Matter Intake,DMI）、日产奶量和乳脂率,试验后期乳蛋白含量有所下降,但差异均不显著（P0.05）;乳尿素氮（Milk Urea Nitrogen,MUN）及尿液尿素氮（Urinary Urea Nitrogen,UUN）含量均呈现下降趋势,血浆尿素氮（Plasma Urea Nitrogen,BUN）先下降后上升,其中试验组MUN和BUN低于对照组（P0.05）,UUN则高于对照组,在试验后期,试验组和对照组UUN分别为48.35和27.52 mmolL-1,差异显著（P0.05）;谷丙转氨酶（Alanine Aminotransferase,ALT）、谷草转氨酶（Aspartate Transaminase,AST）和碱性磷酸酶（Alkaline Phosphatase,ALP）含量均为试验组高于对照组,差异不显著（P0.05）;血浆中总蛋白（Albumin,ALB）和葡萄糖（Glucose,GLU）含量试验组逐渐降低,且低于对照组,但差异不显著（P0.05）;胆固醇（Chinese Hamster Ovary,CHO）的含量试验组逐渐升高,对照组逐渐降低,在试验后期分别为3.64和2.82 mmolL-1（P=0.059）,差异最大。总之,饲喂苜蓿青贮饲料有利于改善奶牛的生产性能和机体代谢能力,由于美拉德反应的发生,试验后期降低了苜蓿青贮饲料营养物质在奶牛体内的代谢利用效果。     

Renal percent clearance ratios in cattle

Renal percent clearance ratios for various electrolytes were determined on nine clinically normal Holstein heifers. Endogenous creatinine serum and urine levels were used to calculate the ratios. The average percent clearance ratios and standard deviations of Na, K, Cl, P, and Ca were 1.97+/-0.63, 49.3+/-9.2, 3.16+/-1.l2, 15.6+/-14.3, and 1.38+/-1.41, respectively. The correlation between Na and Cl percent clearance ratios within a sample was 0.92. A very strong direct correlation of urine creatinine and urine specific gravity was demonstrated.     

尿素及其缓释产品在反刍动物上的应用

本文综述了尿素和尿素缓释产品的营养特性及其在反刍动物上的应用。     

一起群发性奶牛尿素中毒的临床研究

2004年南京某奶牛公寓由于饲养户在奶牛饲料中添加尿素方法不当,引起群发性尿素中毒。该牛群共有奶牛87头,发病64头,药物治疗56头,治愈54头,死亡10头,均为成母牛。作者调查了发病牛群的病史、临床症状、病理变化、治疗情况,对中毒奶牛的血液进行生化分析,并与正常奶牛比较,结果血清谷草转氨酶(AST)、γ-谷氨酰转移酶(GGT)、碱性磷酸酶(ALP)、磷酸肌酸激酶(CK)、磷酸肌酸激酶同工酶(CK-MB)、肌酐(CRE)、尿素氮(UN)、葡萄糖(GLU)、乳酸脱氢酶(LDH-L)等差异极显著(P<0·01),尿素(UREA)、血清K等差异显著(P<0·05),这些指标活性升高说明病牛心肌、胃肠平滑肌、肝肾等存在与病死牛的病理变化相一致的损伤。     

Herd reproductive performance related to urea concentration in bulk milk

Bulk milk samples were collected from 256 dairy herds from 4 districts in Southern Norway: Gudbrandsdal (n = 35), Bergen (n = 15), Hedmark (n = 117) and Hardanger (n = 89).A total of 6–8 samples were collected in each herd during the indoor season. Data concerning reproductive performance, milk production and nutrition were registered for a period of 15 months starting 7 months before the first milk sample was collected. The urea levels obtained during the sampling period were averaged generating a mean urea level of each herd. The mean urea levels were related to reproductive performance.The urea levels within districts showed only minor variations during the sampling period. The mean urea level in Hardanger was significantly higher (p < 0.05) than in the other distrikts. This district also had the lowest fertility. Significant correlations between mean urea level and fertility were observed only in Hedmark. Fertility status (FS), an integrated index, and number of inseminations per animal inseminated were significantly affected by the interaction between mean urea level and district. Herds in Hardanger with cows treated for ovarian cysts had a significantly higher mean urea level (p = 0.02) than herds with non-treated cows.The results appear to support the notion that a negative relationship may exist between bulk milk urea levels and reproductive performance. The great district variations observed indicate, however, that the practical value of such measurements is limited.     

饲粮中添加抗菌肽对肉鸭增重及血清尿素氮、总蛋白水平的影响

240只1日龄肉鸭随机成分4组,每组设3个重复,对照组用基础日粮,试验组在基础日粮上每千克分别添加1、2、3mL抗菌肽制剂。结果显示:1)2、3mL/kg添加量组增重效果显著(P<0.05),3mL/kg添加量组最佳;净肉率升高,达到显著水平(P<0.05),其中主要是胸肌率上升;腹脂率降低但差异不显著(P>0.05);料重比无显著变化(P>0.05)。2)血清总蛋白浓度差异不显著(P>0.05),但尿素氮浓度下降,2、3mL/kg添加量组达显著水平(P<0.05),3mL/kg添加量组最低。     

Renal excretion of urea in reindeer. Effect of nutrition.

Renal reabsorption of urea was studied in 8 9-month old reindeer calves fed low protein (19–34 g crude protein, mostly lichens) and high protein (68–69 g crude protein, lichens + soybean meal) diets.Low protein diets fed for a 3-month period resulted in an average renal reabsorption of 93% of the filtered urea, while only 50 % was reabsorbed on the high protein ration. It was calculated that if the reabsorbed urea was used completely for protein synthesis in the rumen, 4 g crude protein could be made daily in the lichen fed animals. This amount would be a very significant contribution to the nitrogen economy of animals which are usually in a negative nitrogen balance when lichens are the main food consumed.     

饲料及其原料中尿素检测方法的研究进展

本文就近年来国内外报道饲料及其原料中尿素检测方法的相关原理及应用进行综述,并对建立健全统一的尿素检测体系提出建议。     

高尔夫清场工程在林区场地的施工方法

最近几年我国高尔夫球场数量稳定增长,但是不合理的建造过程对球场周围的生态环境造成极大破坏。如何科学高效的建造一个环保型球场已经备受业内人士关注。本研究针对林区球场的特点,介绍了高尔夫球场建造中清场工程的施工方法,将清场工程分为按图清场、彻底清场、局部清场和临时清场4个阶段,并分别介绍了这4个阶段的工作任务和方法。从球场开工到竣工,测量工作贯穿了球场的全部建造过程。本研究还着重介绍了在清场工程前后测量工作的理论方法及其应用。     

Inaccuracy of routine creatinine measurement in canine urine

BACKGROUND: Urine creatinine concentration often is used in ratios such as urine protein:creatinine to compensate for dilution or concentration of spot urine samples. OBJECTIVE: The purpose of this study was to compare the accuracy of different techniques of urine creatinine measurement currently available for veterinary practitioners. METHODS: In 104 samples of canine urine diluted 1:20 with distilled water, creatinine concentration was measured using a kinetic Jaffé reaction assay, and an enzymatic technique on an automatic analyzer (Elimat) and 3 benchtop analyzers (Reflovet, Scil; Vitros DT2, Ortho-Clinical Diagnostics; Vettest 8008, IDEXX) used in veterinary practice. RESULTS: The Jaffé and enzymatic techniques on the Elimat were not significantly different, and their inaccuracy tested with human control urines was <5%. The benchtop analyzers underestimated creatinine concentration, especially at concentrations >2000 mg/L. Inaccuracy was higher with multilayer slide technology systems (Vitros and Vettest) than with the Reflovet system. Results were approximately 25% and 2% lower, respectively, than with the Elimat at urine creatinine concentrations about 2000 mg/L. CONCLUSION: Inaccuracy in urine creatinine measurements using benchtop analyzers should be taken into account when defining decision thresholds, which should be corrected according to the method used to avoid misinterpretations.     

反刍动物饲用尿素缓(控)释技术研究进展

尿素缓(控)释技术包括物理缓释法、化学缓释法、抑制脲酶活性法和近年来出现的包被尿素法。本文对几十年来关于饲用尿素缓(控)释方法进行了综述,指出物理方法中以糊化淀粉尿素和糖蜜尿素舔砖较为可行,但这两种方法并没有提高尿素氮的利用率;化学缓释法中以羟甲基脲最为可行;抑制脲酶活性法普遍存在瘤胃微生物对之产生适应性的问题;包被尿素法可以根据瘤胃微生物对氨气的需要进行控释,开发经济、无毒无害并可生物降解的包膜材料是今后研究的重点。不同生态区位瘤胃微生物对氨气的动态营养需要模式是进一步提高饲用尿素缓(控)释效果的理论基础。     

Urinary lipid production profile in canine patients with splenic mass

Polyunsaturated fatty acids (PUFAs), including arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), are metabolized to various lipid mediators. The profile of these lipid metabolites excreted into the urine reflects inflammatory state of the body and disease conditions. In this study, we quantified 156 types of lipids in urine samples of dogs with splenic mass, using liquid chromatography-tandem mass spectrometry. We found that metabolites of prostaglandin (PG) E₂, F_2α, and D₂, 8-iso-PGF_3α, lyso-platelet activating factor, and 14,15-leukotrien C₄ significantly increased in urine samples of dogs with splenic mass compared to that of healthy dogs. These observations may reflect general inflammatory responses and will help better understanding of the canine splenic mass.     

Type‐I interferon regulates matrix metalloproteinases clearance of the bovine endometrial spheroid

This study investigated the effect of type‐I interferon (IFN) on the expression of matrix metalloproteinases (MMPs) of the bovine endometrial stromal cells (BES) and epithelial cells (BEE). The cells were separated and purified from the caruncles and cultured in DMEM/F‐12 containing 10% fetal bovine serum. Spheroids were generated by using ascorbate. Zymograms of the supernatant showed that BEE predominantly expressed MMP‐9, whereas MMP‐2 was expressed in BES and homo‐spheroids. While MMPs expression was not detected in hetero‐spheroids. Real‐time quantitative PCR revealed that type‐I IFN and P4 suppressed the gene expression of MMP‐2 and MMP‐9 in hetero‐spheroids, respectively. On the other hand, gelatin zymography analysis of the supernatant showed that type‐I IFN strongly promote the clearance of MMPs. While zymograms of the MMPs stocked in the hetero‐spheroids were significantly reduced by type‐I IFN. Phenylmethanesulfonyl fluoride and leupeptin (both are serine proteinase inhibitors) significantly repressed the clearance of MMP‐2 and MMP‐9 induced by type‐I IFN. Moreover, collagen fibers in hetero‐spheroids significantly decreased after the treatment with type‐I IFN. In conclusion, it was suggested that type‐I IFN participate in the tissue remodeling by regulation the clearance of MMPs.     

Effect of nitrogen supplementation and zilpaterol-HCl on urea kinetics in steers consuming corn-based diets

We studied effects of zilpaterol-HCl on steers consuming corn-based diets with nitrogen (N) supplementation provided by dried distillers grains with solubles (DDGS) or urea. Two sets of six steers (approximately 350 kg) were used in two replicates of similarly designed trials. Within each replicate, three steers were fed 60 mg/day of zilpaterol-HCl throughout the trial and three steers received no zilpaterol-HCl. Within zilpaterol treatment, three corn-based dietary N treatments were offered in Latin square designs: control (9.6% crude protein), urea (UREA; 12.4% crude protein) or DDGS (13.7% crude protein). Total feed intake was unexpectedly greater (p < 0.01) with zilpaterol feeding but was not affected by dietary N (p = 0.76). Nitrogen intake was greater (p < 0.01) when zilpaterol was fed and was greater (p < 0.05) for DDGS and UREA than for control. Despite greater N intake, zilpaterol did not affect urea entry rate (p = 0.80) or urea-N recycled to the gastrointestinal tract (GER; p = 0.94). As a percentage of N intake, urea entry rate (p = 0.19) tended to be less when zilpaterol was fed (91 vs. 123% of N intake), and GER was numerically (p = 0.34) less (72 vs. 92% of N intake). Microbial N flow was greater (p = 0.02) for zilpaterol than for control but did not differ (p = 0.78) among dietary N treatments. As a percentage of N intake, microbial N flow was unaffected by zilpaterol (p = 0.97), but was greater (p < 0.05) for control than DDGS or UREA. The lack of change in urea entry and GER in response to zilpaterol, despite greater N intake, as well as lower urea entry and GER when expressed as proportions of N intake provide some evidence that the amount of N available for urea production and recycling was reduced by zilpaterol.     

Effects of supplement feeding order on lactation, diurnal variation of ruminal ammonia and urea in the blood and milk of dairy cows

The present study examined the effects of feeding order of grain and protein supplements on ruminal nitrogen (N) loss through the diurnal variation of ruminal ammonia N and urea N in the blood and milk of dairy cows. Three ruminally fistulated cows were used in a 3 × 3 Latin square arrangement of treatments; that is, grain supplement fed at the first feed and then the protein supplement at the second (GS‐1st), protein supplement fed first and then the grain supplement (PS‐1st), and the grain and protein supplements mixed and divided into equal portions fed at each supplement feeding time (GP‐mix). No differences in the lactation parameters were observed among the treatments. In GS‐1st treatment, the increase in the concentration of ruminal ammonia N was inhibited after feeding, and the concentration was lower (P < 0.05) than with the other treatments 1–2 h after basal feeding. The concentrations of urea N in the blood and milk with the GS‐1st treatment were the lowest of all treatments throughout the sampling times, and were lower (P < 0.05) than with the GP‐mix treatment except for blood levels 1 h after basal feeding. The results suggest that grain feeding before protein feeding can reduce ruminal N loss.     

Nitrogen digestion and urea recycling in Hokkaido native horses fed hay‐based diets

Nitrogen (N) digestion and urea‐N metabolism in Hokkaido native horses fed roughage‐based diets containing different types and levels of protein sources were studied. Horses (173 ± 4.8 kg) fitted with an ileum cannula were fed four diets consisting of 100% timothy hay (TH), 88% TH and 12% soybean meal (SBM), 79% TH and 21% SBM, and 51% TH and 49% alfalfa hay at 2.2% of body weight. Dietary protein content varied from 5% to 15% of dry matter. Apparent N digestibilities in the pre‐cecum and total tract for the TH diet were lower than those for other diets. However, the proportion of post‐ileum N digestion to N intake was not affected by the diets. Urea‐N production was linearly related to N intake, but gut urea‐N entry was not affected by the diets. The proportion of gut urea‐N entry to urea‐N production tended to be higher for the TH diet (57%) than the two SBM diets (39%). Anabolic use of urea‐N entering the gut was not affected by the diets (20–36% of gut urea‐N entry). These results indicate that urea‐N recycling provides additional N sources for microbial fermentation in the hindgut of Hokkaido native horses fed low‐quality roughages.     

尿素水平对青山羊血液生化指标的影响

应用饲养试验与氮平衡试验,研究了不同尿素水平的日粮对青山羊血清总蛋白(STP)、血清清蛋白(ALB)、血清球蛋白(GLB)、血清清球蛋白比值(A/G)、血清尿素氮(SUN)及血清谷丙转氨酶的含量变化的影响。试验采用4×4拉丁方试验设计,试验分4个阶段,在基础日粮一致的情况下,采用4、9、14、0(对照)g/kg·DM4种不同的处理,试验结果表明:不同尿素水平极显著影响ALB、SUN浓度和GPT活性浓度(P<0.01),对血清清球比(A/G)无显著差异(P>0.05),尿素水平与STP、GLB浓度存在负相关;血清含氮生化指标STP、ALB、GLB、A/G、GPT、SUN随时间呈动态变化,出现高峰的时间比瘤胃氨浓度出现的时间平均推迟1～2h。进食尿素后,血液生化指标由平稳逐渐缓慢升高到高峰,随后又下降并趋于平衡。