Plasma Adrenocorticotropin Concentration in Healthy Horses and in Horses With Clinical Signs of Hyperadrenocorticism

Pituitary adenomas are commonly reported in older horses. The typical clinical signs associated with this condition, also known as equine Cushing's disease (ECD), are related to increased adrenocorticotropin (ACTH) production resulting in hyperadrenocorticism. The primary purpose of this study was to determine whether plasma ACTH concentrations differed between cushingoid and healthy horses. The second objective was to determine the effects of blood sample handling techniques on ACTH concentrations. A commercial human ACTH radioimmunoassay (RIA) was used to quantify equine plasma ACTH. Intra-assay and interassay variations, as well as dilutional parallelism were determined during the RIA validation. Plasma ACTH concentrations were evaluated in a group of healthy equids composed of 18 horses and 9 ponies, and in 22 equids with a clinical diagnosis of hyper adrenocorticism (11 horses and 11 ponies). The mean plasma ACTH concentrations in healthy horses and ponies, (18.68 ± 6.79 pg/mL (mean ± SD) and 8.35 ± 2.92 pg/mL, respectively), were significantly different (P = .009). The mean plasma ACTH concentration in horses and ponies with ECD, (199.18 ± 182.82 pglmL and 206.21 ± 319.56 pg/mL, respectively), were significantly higher than the mean ACTH concentration in the control animals (P < .001). Plasma ACTH concentrations appeared to be a sensitive and specific indicator of ECD in horses and ponies. ACTH concentrations measured in plasma samples kept at room temperature (19°C) as long as 3 hours after blood collection were not statistically different from those of samples kept at 1°C. J Vet Intern Med 1996;10:1–6. Copyright 1996 by the American College of Veterinary Internal Medicine .     

Plasma Procalcitonin Concentration in Healthy Horses and Horses Affected by Systemic Inflammatory Response Syndrome

Background

The diseases most frequent associated with SIRS in adult horses are those involving the gastrointestinal tract. An early diagnosis should be the goal in the management of horses with SIRS.

Objective

The objective of this study was to evaluate the plasma procalcitonin (PCT) concentration in healthy and SIRS horses to assess differences between the two groups.

Animals

Seventy‐eight horses (30 healthy and 48 SIRS).

Methods

Prospective in vivo multicentric study. Horses were classified as SIRS if at least 2 of the following criteria were met: abnormal leukocyte count or distribution, hyperthermia or hypothermia, tachycardia, tachypnea. Healthy horses showed no clinical or laboratory signs of SIRS. Plasma PCT concentrations were measured with a commercial ELISA assay for equine species. Results were expressed as mean±standard deviation. T‐test for unpaired data was performed between healthy and SIRS group. SIRS group was divided in 4 subgroups and t‐test was performed between healthy versus each subgroup.

Results

PCT concentrations in healthy and SIRS horses were 18.28 ± 20.32 and 197.0 ± 117.0 pg/mL, respectively. T‐test showed statistical differences between healthy versus SIRS group and between healthy versus all subgroups.

Conclusions and Clinical Importance

Results showed an increase in PCT concentration in SIRS horses as previously reported in humans and dogs. PCT could be used as a single assay in equine practice for detection of SIRS.     

玉米秸秆及青贮饲料的细胞壁成分体外消化性能比较

利用体外消化试验法，对吉单4011和四单29两品种玉米的秸秆和青贮饲料进行了干物质和细胞壁成分的消化率和消化速度常数的测定，吉单4011的干物质（DM）和细胞壁成分（OCW）的有效消化率分别是57．4％和48．9％，吉单29分别是58．8％和53．9％。两品种玉米青贮饲料OCW的消化速度常数显著高于秸秆，吉单4011的秸秆和青贮饲料分别是4．85％和4．52％，吉单29分别是5．81％和7．11％。结果表明，通过青贮，可以提高玉米秸秆细胞壁的消化率和消化速度常数，秸秆中OCW含量高的玉米品种更适合青贮。     

粗蛋白水平对绵羊日粮养分后肠道消化的影响

本文旨在探讨粗蛋白(CP)水平对绵羊日粮养分后肠道及全消化道消化的影响。试验选4只装有永久性回肠瘘管的4月龄阉羊进行4×4拉丁方试验,定量饲喂4种等能量、相同中性洗涤纤维(NDF)水平、CP水平分别为11.8%(P12组)、14.0%(P14组)、15.9%(P16组)和17.8%(P18组)的日粮。结果表明:随着CP水平提高,日粮DM消化率显著(P<0.05)增加,有机物(OM)消化率无显著变化,CP消化率提高(P<0.01),NDF、酸性洗涤纤维(ADF)、半纤维素(HC)和纤维素(CEL)消化率增加(P<0.01),P12组的各项指标最低。日粮养分后肠道消化占总消化量的比率DM分别为31.3%、29.1%、28.8%和28.6%;OM分别为22.4%、20.8%、20.3%和20.0%;CP分别为19.3%、15.1%、14.3%和13.7%;NDF相应为28.2%、24.7%、23.4%和22.8%;ADF相应为25.3%、21.1%、19.9%和19.4%,P12组日粮ADF后肠道消化比率显著(P<0.05)高于其他3种日粮;HC分别为32.0%、29.5%、27.9%和27.4%;CEL分别为21.1%、18.9%、18.1%和17.9%,P12组日粮CEL后肠道消化比率显著(P<0.05)高于其他3种日粮;淀粉在后肠道消化不到1%。不同的粗蛋白水平对绵羊日粮养分后肠道的消化有一定的影响。     

Short-term Evaluation of Serum Amyloid A after Exercise in Clinically Healthy Horses

Serum amyloid A (SAA), the major equine acute-phase protein, is often measured after the race to investigate whether poor performances could depend on inflammation. The aim of this study was to assess whether there is an increase in concentration of SAA in serum samples collected from 12 clinically healthy Standardbred horses 1 hour after a standard race. Exercise induced an increase in red blood cells, hematocrit, and total proteins but not in SAA. However, a two- to threefold increase of SAA concentration as compared with prerace values was found in three horses. In conclusion, the concentration of SAA in most of the samples collected 1 hour after the race remains unchanged as compared with prerace samples. However, individual variability in response to exercise exists. The evaluation of SAA immediately after the race is not clinically useful.     

不同比例的羊草纤维素源对五龙鹅消化代谢的影响

选取18月龄的健康五龙鹅24只,随机分为4个组,每组6个重复。各试验组日粮添加的羊草粉含量分别为12.70%、16.70%、21.00%、25.80%,采用全收粪法进行消化代谢试验,检测饲料和粪便中的多种营养成分,确定其消化率。结果表明：在代谢能（ME）和粗蛋白（CP）等摄入量一致的条件下,随着羊草粉添加水平的提高,CF的消化率为13.00%-18.40%,中性洗涤纤维（NDF）14.10%-21.47%,酸性洗涤纤维（ADF）15.40%-22.29%;组间净蛋白利用率（NPU）及氮（N）的沉积量差异不显著（P〉0.05）,粪中氨态氮（NH3-N）浓度显著下降（P〈0.05）,各种氨基酸表观消化率（AAAD）较高（77.30%-91.78%）;P的表观消化率各组间差异不显著（P〉0.05）,而Ca的表观消化率呈递减趋势（P〈0.05）;AKP活性与CF、NDF和ADF的消化率呈显著负相关（P〈0.05）,与Ca、蛋氨酸（Met）、胱氨酸（Cys）消化率呈显著正相关（P〈0.05）;ACP活性与Ca、P表观消化率呈显著正相关（P〈0.05）;其它四种酶的活性与CF、NDF、ADF消化率,Ca、P、Met、Cys表观消化率相关不显著。     

Analysis of Circulating Immune Complexes in the Serum of Clinically Healthy Horses

The aim of this study was to determine the level of circulating immune complexes (CIC) in equine serum and the electrophoretic properties of the protein fraction thereof. The study was carried out using 42 clinically healthy breeding horses of noble half-blood. The average extinction value of CIC's in equine serum was E450 nm = 0.278 ± 0.09 nm. Generally, 23 protein fractions were identified in the molecular mass range between 294 and 25 kDa. Eight fractions whose molecular masses were 137, 72, 65, 52, 42, 32, 28, and 26 kDa, respectively, appeared in all analyzed samples. In 20 of the analyzed serum an additional nine protein fractions whose molecular masses were 260, 110, 84, 78, 67, 62, 57, 45, and 39 kDa, respectively, were identified. Circulating immune complexes are a source of information about immunologic processes that take place in mammals. Determining the average values of CIC levels and identifying the electrophoretic profile of proteins in clinically healthy horses could be useful in research and diagnostics.     

Serum Amyloid A (SAA) Concentration after Vaccination in Horses and Mules

Serum amyloid A (SAA) is a sensitive acute-phase response (APR) marker in equids. Prominent APRs with elevations of SAA concentrations ([SAA]) have been reported after vaccination. The authors hypothesized that vaccination with an inactivated EHV-1/-4 vaccine would cause increase in [SAA] and antibody responses and that higher [SAA] would be positively correlated with the antibody titer in both equids. Twelve Haflinger horses and 12 mules were included in this longitudinal prospective study. All horses and mules were vaccinated with a commercially available EHV-1/-4 vaccine. Blood was sampled before and after vaccination to measure [SAA] and virus-neutralizing response (VN-T). In horses and mules, significantly higher [SAA] were measured on days 1, 3, and 5 after EHV-1/-4 vaccination; [SAA] on day 1 after vaccination were only measured in animals that developed fever, where mean [SAA] were significantly higher in horses than in mules (horses: 1,365.75 ± 87.64 mg/L, mules: 615.5 ± 153.444 mg/L) (P > .05). Four horses and 2 mules developed fever after vaccination, lasting for ≤24 hours. Increased antibody responses (VN-T) on days 7 and 14 after vaccination were observed in all animals, whereas mules showed higher overall antibody responses. Nevertheless, [SAA] did not correlate with the intensity of the antibody responses (VN-T) stimulated by the vaccine (P < .05). EHV-1/-4 vaccination caused a prominent APR, higher in horses than in mules, but [SAA] did not correlate with antibody responses. Measuring [SAA] after vaccination could help identify severe APRs that may require longer resting intervals before training or competition.     

Clinical Feasibility and Airway Deposition of Nebulized Voriconazole in Healthy Horses

Voriconazole (VRC) is a potential treatment for pneumomycosis in horses. The objectives of this study were to determine if the delivery of Vfend using a Flexineb nebulizer produced clinically significant [VRC] in lower airways. The hypothesis was that [VRC] after delivery by nebulization would be greater in the pulmonary epithelial lining fluid than plasma. A secondary objective was to determine [VRC] in upper airways through the collection of nasopharyngeal wash (NPW) samples. Voriconazole solution [Vfend-6.25 mg/mL, 100 (n = 2), 200 (n = 3), 500 (n = 1) mg] was nebulized once in 6 healthy geldings. Clinical responses, duration of nebulization, and [VRC] at various time points (up to 8 hours) in plasma, bronchoalveolar lavage fluid (BALF) supernatant and cell pellet, and NPW samples were recorded. Voriconazole (Vfend-6.25 mg/mL, 200 mg) was nebulized in 5 additional, healthy geldings, and [VRC] was measured in NPW samples pre- and postnebulization at time points up to 8 hours. The antifungal activity of BALF and NPW samples was determined using agar disk diffusion. Concentrations of voriconazole were below detection in plasma, BALF supernatant, and cell pellets for all time points and doses except the BALF cell pellet (0.4 μg/g) immediately after nebulization of 500 mg. For 5 horses, administered 200 mg of Vfend, mean [VCR] in NPW at the end of nebulization and 1, 6, and 8 hours postnebulization were: 30.8 ± 29, 1.0 ± 0.84, 0.2 ± 0.19, and 0.34 ± 0.67 μg/mL, respectively. Only NPW samples obtained immediately postnebulization showed antifungal activity. A nebulized Vfend solution is not recommended for the treatment of pneumomycosis in horses.     

Relationship of Some Oxidative Stress Biomarkers in Jumper Horses After Regular Training Program

In the present study, the redox status of blood samples, by assessing the total oxidant status (TOS), the total antioxidant capacity (TAC), and the oxidative stress index (OSI), together with the nitric oxide radical (NO^•) metabolite (NOx) content, was evaluated in trained horses. Moreover, the oxidative damage to lipids and proteins, analyzed as thiobarbituric acid reactive substances (TBARS) and advanced oxidation protein products (AOPP), was also assessed. Twenty-five regularly trained Italian Saddle horses (7–10 year old, 12 geldings and 13 females, mean body weight 480 ± 30 kg) were enrolled in this study. Animals were carried on with their specific training programs for jumpers for 6 days per week with a day of rest, during which blood sampling was performed. On obtained serum samples, TOS, TAC, NOx, TBARS, and AOPP were measured. Our results showed significant linear correlations among markers of redox potential (TAC, TOS, and OSI) and among TOS and NOx with serum markers of lipid and protein oxidative injury (TBARS and AOPP). Furthermore, multiple linear regression analysis has shown that lipid peroxidation and protein oxidation levels are related to the content of oxidant substances (TOS and NOx). The obtained data can be useful to assess the status of an athletic horse and its adaptability to physical effort, providing an opportunity to modify the training schedule to achieve the desired performance.     

Hemodynamic and Electrocardiographic Effects of Magnesium Sulfate in Healthy Dogs

We investigated the effects of graded dosages of magnesium given i.v. to anesthetized dogs on blood pressure, cardiac output, and electrophysiology. Magnesium was infused at 0.12 mEq/kg/minute until ventricular fibrillation occurred naturally or was provoked by programmed electrical stimulation or until arrest of the sinuatrial node in 8 dogs. Plasma total magnesium concentrations doubled in 1 minute of that infusion rate, and a hemodynamically safe plasma concentration of 12.2 mEq/L was achieved after 16 minutes of infusion. Heart rate, inotropy, lusitropy, and cardiac output increased up to a cumulative infusion dosage of magnesium of 1.0-2.0 mEq/kg, which produced plasma magnesium concentrations of 8.5-12.2 mEq/L (n = 5). Above the cumulative infusion dosage, inotropy decreased and lusitropy increased until death occurred between cumulative infusion dosages of 5.9 mEq/kg and 10.9 mEq/kg. Arterial pressure and vascular resistance decreased, and PQ interval and QRS complex increased, in a dose-dependent fashion. The relationship between ionized and total magnesium was y = 0.624x - 0.542 (r2 = .986), where y is ionized and x is total magnesium in mEq/L in 3 dogs. In conclusion, a cumulative infusion dosage of 0.1-0.2 mEq/kg of magnesium may be given without changing hemodynamic parameters, but with higher cumulative infusion doses heart rate accelerates. Hemodynamic parameters except those related to blood pressure continued to increase to a cumulative infusion dosage of 2.0 mEq/kg. At higher cumulative infusion dosages dogs became hypotensive and the PQ interval was prolonged. However, dangerous arrhythmias were not provoked until a total dosage of 3.9 mEq/kg.     

Gender Differences of Oxidative Stress Biomarkers and Erythrocyte Damage in Well-Trained Horses During Exercise

The aim of this study was to determine the effects of gender differences on the blood oxidative stress biomarkers, antioxidant defenses, and resistance of erythrocytes to hemolytic agents of trained horses before and after exercise. The study was carried out on nine mares and 14 stallions of Ukrainian Warmblood well-trained horses, involved in jumping, eventing, and dressage. Oxidative stress biomarkers, antioxidant defenses, and osmotic resistance of erythrocytes were assessed. Trained stallions showed a decrease in lipid peroxidation and higher glutathione reductase activity, whereas mares presented a higher superoxide dismutase activity after exercise. The resistance of erythrocytes was similar in female and male. No statistically significant differences were observed in the percentage of hemolyzed erythrocytes between after and before exercise. A correlation between the oxidative stress biomarkers and antioxidant defenses in the stallions after exercises were observed, which may indicate a protective response of superoxide dismutase and catalase against exercise-induced oxidative stress.     

精氨酸分解代谢及其在马健康养殖中的应用研究进展

精氨酸,又名2-氨基-5-胍基戊酸,是哺乳动物体内一氧化氮的唯一氮供体和尿素循环的关键氨基酸之一。精氨酸是20种蛋白质氨基酸中碱性最强的氨基酸,具有亲水性侧链。饲粮中添加适量的精氨酸可以调控母畜的生殖系统血流量及胎盘对营养物质的转运和代谢,进而提高繁殖性能。本文主要从精氨酸分解代谢以及饲粮中补喂精氨酸对马生殖系统血流量、血液参数和胎盘功能等方面的影响进行总结,为精氨酸在马健康养殖中的应用提供科学的理论参考。     

Effects of Blood Contamination on Peritoneal D-Dimer Concentration in Horses with Colic

Background: Peritoneal D-Dimer concentration can be determined to assess peritoneal fibrinolysis activity in horses with gastrointestinal disorders. However, blood contamination of peritoneal fluid may occur during collection and could alter peritoneal D-Dimer concentration.
Hypothesis/Objectives: Blood contamination in peritoneal fluid does not affect interpretation of peritoneal D-Dimer concentration in horses with colic.
Animals: Thirty-four horses with colic and 4 healthy horses.
Methods: Peritoneal fluid and blood samples were simultaneously collected upon admission. Then, peritoneal fluid was serially contaminated with the horse's own blood; final contaminations corresponded to 1, 5, 10, and 20% of blood in peritoneal fluid. D-Dimer concentration was determined in blood, peritoneal fluid, and contaminated peritoneal fluid samples. Data were analyzed using a longitudinal linear model and a generalized estimating equations analysis to assess the quantitative and qualitative variations of the effect of blood contamination on peritoneal D-Dimer concentration.
Results: Peritoneal D-Dimer concentration was only quantitatively affected when peritoneal fluid was contaminated at 20% of blood. However, when using increasing cut-off values of peritoneal D-Dimer concentration (100, 2,000, 8,000, and 16,000 ng/mL), this effect disappeared at the highest cut-off values (8,000 and 16,000 ng/mL). When peritoneal fluid contamination was grouped as "minimally contaminated" (≤1% of blood) and "highly contaminated" (≥5% of blood), no significant differences on D-Dimer concentration between both groups at each cut-off value were observed.
Conclusions and Clinical Importance: Although quantitative results of peritoneal D-Dimer concentration could be affected by high levels of blood contamination (≥20%), interpretation of increased peritoneal fibrinolytic activity was not significantly affected.     

糊化淀粉尿素对山羊消化代谢和增重的效果

选择３６只本地白山羊随机分成３组进行饲养试验。配制３种分别含有豆粕、糊化淀粉尿素和尿素并达到等能等氮水平的混合材料，定量饲喂，干草自由采食。３５天饲养试验后，每组选３只阉公羊作上述３种日粮的消化代谢试验。结果表明：（１）３种日粮的粗纤维表现消化率分别为６４．６５±５．５８％、６６．１０±３．７２％和６１．４９±７．６１％。（２）３种日粮的氮代谢率分别为２５．８３±４．８６％、２２．２５±７．０％和１９．３６±３．９８％，糊化淀粉尿素日粮比尿素日粮提高１４．９３％。（３）与尿素日粮相比，动物采食含糊化淀粉尿素日粮后外周血液尿素浓度有所下降，且动态变化也相对平稳。（４）３个日粮组的日增重分别为６８．４５±３５．８４、７０．８３±３１．２８和６１．９１±３１．８０ｇ／只，差异不显著（Ｐ＞０．０５）；每千克增重所需日粮粗蛋白质分别为９２６．５、９５２．２和１１３３．２ｇ，尿素日粮的饲喂效果最差。结果分析指出：糊化淀粉尿素产品能有效改善尿素氮的利用率，并能达到与豆粕相同的增重效果。