Plasma Lactate Concentrations Research Articles

337-OR: Hyperglycemia Lowers Lactate Clearance during Exercise in Type 1 Diabetes

To determine the role of hyperglycemia on lactate metabolism during exercise in type 1 diabetes (T1D), we studied 7 T1D participants during two visits (EuLoI; euglycemia, low insulin; HyLoI: hyperglycemia, low insulin) in random order. 7 nondiabetic (ND) subjects were studied on one occasion (EuLoI). Lactate turnover was measured using [1-13C] lactate before, during and after 60 min of exercise at 65% VO2 max. While lactate clearance was lower (p=0.031) during exercise at HyLoI than EuLoI in T1D, it was not different between T1D and ND subjects at EuLoI (p=0.707). In contrast, rate of lactate appearance during exercise was not different between EuLoI vs. HyLoI in T1D (p=0.129), demonstrating that higher plasma lactate concentration during exercise in HyLoI (p<0.001) was due to reduced lactate clearance in T1D. The results from this pilot study indicates that hyperglycemia modulates lactate metabolism during exercise by lowering lactate clearance in T1D individuals. This novel observation implies that exercise during hyperglycemia can lead to higher circulating lactate concentrations thus increasing the likelihood of reaching the lactate threshold sooner, in type 1 diabetes. Disclosure D.Romeres: None. Y.Yadav: None. F.Ruchi: None. R.Carter: None. C.Cobelli: None. R.Basu: Consultant; Sparrow Pharmaceuticals Inc, Research Support; Abbott Diabetes, AstraZeneca. A.Basu: None. Funding National Institutes of Health (DK29953 to R.B.), (DK85516 to A.B.)

Medical causes of poor performance and their associations with fitness in Standardbred racehorses.

Poor performance is a multifactorial syndrome of racehorses, commonly associated with subclinical disorders, which can be diagnosed by exercise testing. Describe the prevalence of medical causes of poor performance in Standardbreds unassociated with lameness, and evaluate their relationships with fitness variables measured by exercise treadmill test. Hospital population of 259 nonlame Standardbred trotters referred for poor performance. The horses' medical records were retrospectively reviewed. Horses underwent a diagnostic protocol including resting examination, plasma lactate concentration, treadmill test with continuous ECG and assessment of fitness variables, creatine kinase activity, treadmill endoscopy, postexercise tracheobronchoscopy, bronchoalveolar lavage (BAL), and gastroscopy. The prevalence of different disorders was evaluated, including cardiac arrhythmias, exertional myopathies, dynamic upper airway obstructions (DUAOs), exercise-induced pulmonary hemorrhage (EIPH), moderate equine asthma (MEA), and gastric ulcers (EGUS). The associations of these disorders with fitness variables were investigated individually and using multivariable models. Moderate equine asthma and EGUS were the most common disorders, followed by EIPH, DUAOs, cardiac arrhythmias, and exertional myopathies. Hemosiderin score was positively correlated with BAL neutrophils, eosinophils, and mast cells; increased creatine kinase activity was associated with BAL neutrophilia, DUAOs, premature complexes, and squamous gastric disease. Treadmill velocity at a plasma lactate concentration of 4 mmol/L and at heart rate of 200 beats per minute was negatively affected by BAL neutrophilia, multiple DUAOs, exertional myopathies, and squamous gastric disease. The multifactorial nature of poor performance was confirmed, with MEA, DUAOs, myopathies and EGUS representing the main diseases involved in fitness impairment.

23 Comparison of Whole Cottonseed to a Traditional Supplement (20% Breeder Cubes) in Commercial Beef Cows: Impacts on Animal Performance, Metabolites, and Methane Emissions

Abstract The objective was to compare whole cottonseed (WCS) with a more traditional supplement (20% breeder cube; BC) to determine the impacts on animal performance, metabolites, and methane emissions in beef cows. Cows (n = 24) were assigned to 1 of 2 experimental treatments (BC vs. WCS) based on age and body weight (BW). Supplements were fed individually at 0.9, 1.8, or 2.7 kg per day, resulting in 12 animals per supplement treatment and 4 animals per supplementation level within treatment. Two additional cows served as negative controls. Cows were fed 4 days per week, with supplementation levels being prorated at 1.6, 3.2, and 4.8 kg per feeding. Data collection occurred in 28-day intervals through d 84, with a final collection on d 99 after all cows finished calving. An amount fed per d × d interaction for BW change (P = 0.001) was detected. Cattle that were not supplemented (control) or received 0.9 kg per day lost more BW than cows that received 1.8 or 2.7 kg of supplement per day. There was a body condition score (BCS) change interaction for amount fed per d × d (P = 0.009). There was an amount fed per d × d interaction for back fat thickness (BFT; P = 0.02), and a tendency for an effect of amount fed per day on BFT (P = 0.07). There was a tendency for an amount fed per d × d interaction for fecal score (FS; P = 0.09) indicating that cattle receiving different amounts of supplement had varying trends in FS over time. A day effect was also observed for fecal score (P = 0.00003). There were no interactions (P ≥ 0.55), effect of treatment (P = 0.85), or effect of amount fed per d (P = 0.45) for fecal pH. A treatment × amount fed per d × d interaction for plasma glucose concentrations (P = 0.04) was detected. An amount fed per d × d interaction was detected for plasma lactate concentrations (P = 0.01) indicating that cattle receiving different amounts of supplement had different trends in lactate concentrations over time. An effect of amount fed per d on plasma lactate concentrations (P = 0.05) was also observed. A tendency for an amount fed per d × d interaction for plasma urea nitrogen (PUN; P = 0.06) was observed indicating that cattle receiving different amounts of supplement had varying trends in PUN over time. No treatment effect on methane emissions was observed between cows consuming BC and WCS (P = 0.68). This experiment suggests that the supplementation of BC or WCS had minimal impacts on performance, metabolites, or methane emissions, but some interactions existed between supplementation source or level and day.

The safe use of metformin in heart failure patients both with and without T2DM: a cross-sectional and longitudinal study.

This study investigated the safe use of metformin in patients with (1) type 2 diabetes mellitus (T2DM) and heart failure on metformin, and (2) heart failure without T2DM and metformin naïve. Two prospective studies on heart failure patients were undertaken. The first was a cross-sectional study with two patient cohorts, one with T2DM on metformin (n=44) and one without T2DM metformin naive (n=47). The second was a 12-week interventional study of patients without T2DM (n=27) where metformin (500 mg immediate release, twice daily) was prescribed. Plasma metformin and lactate concentrations were monitored. Individual pharmacokinetics were compared between cohorts. Univariable and multivariable analysis analysed the effects of variables on plasma lactate concentrations. Plasma metformin and lactate concentrations mostly (99.9%) remained below safety thresholds (5 mg/L and 5 mmol/L, respectively). Metformin concentration had no significant relationship with lactic acidosis safety markers. In the interventional study, New York Heart Association (NYHA) II (p<0.03) and III (p<0.001) grading was associated with higher plasma lactate concentrations, whereas male sex was associated with 47% higher plasma lactate concentrations (p<0.05). The pharmacokinetics of heart failure patients with and without T2DM were similar. We observed no unsafe plasma lactate concentrations in patients with heart failure treated with metformin. Metformin exposure did not influence plasma lactate concentrations; however, NYHA class and sex did. The pharmacokinetics of metformin in heart failure patients are similar irrespective of T2DM. These findings may support the safe use of metformin in heart failure patients with and without T2DM.

Forced-air prewarming prevents hypothermia during living donor liver transplantation: a randomized controlled trial

Despite various intraoperative thermal strategies, core heat loss is considerable during liver transplantation and hypothermia is common. We tested whether forced-air prewarming prevents hypothermia during liver transplantation. Adult patients undergoing living donor liver transplantation were randomly assigned to non-prewarming group (n = 20) or prewarming group (n = 20). Patients in prewarming group underwent 30-min forced-air warming before anesthetic induction. During surgery, core temperature was measured in the pulmonary artery. The primary outcome was intraoperative hypothermia (< 36.0 °C). The secondary outcomes included plasma lactate concentration. Intraoperative hypothermia risk was significantly lower in prewarming group than in non-prewarming group (60.0% vs. 95.0%, P = 0.020). The difference in hypothermia incidence between groups was greater in the post-induction phase (20.0% vs. 85.0%, P < 0.001) than in the anhepatic or post-reperfusion phase, suggesting that prewarming mainly acts on preventing post-induction core-to-peripheral heat redistribution. Hypothermia duration was significantly shorter in prewarming group (60 [0–221] min vs. 383 [108–426] min, P = 0.001). Lactate concentration decreased during 3 h after graft reperfusion in prewarming group, whereas it continuously increased in non-prewarming group (− 0.19 [− 0.48 to 0.13] mmol/L vs. 1.17 [3.31–0.77] mmol/L, P = 0.034). In conclusion, forced-air prewarming decreases the incidence and duration of intraoperative hypothermia with potential clinical benefit while mainly acting by preventing the core-to-peripheral heat redistribution.Clinical trial registration: Registered at the Clinical Research Information Service (https://cris.nih.go.kr, [KCT0003230]) on 01/10/2018.

Elamipretide mitigates ischemia-reperfusion injury in a swine model of hemorrhagic shock

ischemia-reperfusion injury (IRI) after hemorrhage is potentiated by aortic occlusion or resuscitative endovascular balloon occlusion of the aorta (REBOA). Given the central role of mitochondrial injury in shock, we hypothesized that Elamipretide, a peptide that protects mitochondria, would mitigate IRI after hemorrhagic shock and REBOA. Twelve pigs were subjected to hemorrhagic shock and 45 min of REBOA. After 25 min of REBOA, animals received either saline or Elamipretide. Animals were transfused with autologous blood during balloon deflation, and pigs were resuscitated with isotonic crystalloids and norepinephrine for 4.25 h. Elamipretide-treated animals required less crystalloids than the controls (62.5 [50–90] and 25 [5–30] mL/kg, respectively), but similar amounts of norepinephrine (24.7 [8.6–39.3] and 9.7 [2.1–12.5] mcg/kg, respectively). Treatment animals had a significant reduction in serum creatinine (control: 2.7 [2.6–2.8]; Elamipretide: 2.4 [2.4–2.5] mg/dL; p = 0.04), troponin (control: 3.20 [2.14–5.47] ng/mL, Elamipretide: 0.22 [0.1–1.91] ng/mL; p = 0.03), and interleukin-6 concentrations at the end of the study. There were no differences in final plasma lactate concentration. Elamipretide reduced fluid requirements and protected the kidney and heart after profound IRI. Further understanding the subcellular consequences of REBOA and mitochondrial rescue will open new therapeutic avenues for patients suffering from IRI after hemorrhage.

Effect of high ambient temperature on physiological responses during incremental exercise in Thoroughbred horses

Several reports have suggested that the risk of exertional heat illness (EHI) in Thoroughbred racehorses increases in high ambient temperatures. Heat dissipation in horses during exercise becomes less efficient when the body temperature and ambient temperature are close. Therefore, we hypothesised that exercise at 40 °C may increase body temperature, oxygen consumption, and cardiac output during incremental exercise tests compared to 20 and 30 °C. Six trained Thoroughbred horses were studied in a randomised, crossover design at three ambient temperatures with a 6-day washout period. Using a 3% inclined treadmill, horses performed incremental exercise tests at 1.7, 3.5, 6, 8, and 10 m/s for 90 s at ambient temperatures of 20, 30, and 40 °C. The effects of ambient temperature at 10 m/s on physiological variables were analysed using mixed models (P&lt;0.05). Pulmonary arterial temperature and rectal temperature at 40 °C were higher than those at 20 °C (P&lt;0.001) and 30 °C (P&lt;0.001). Similarly, oxygen consumption (vs 20 °C, P=0.009; vs 30 °C, P=0.006) and cardiac output (vs 20 °C, P=0.001; vs 30 °C, P=0.001) at 40 °C were higher than those at 20 and 30 °C. Arterial O2 partial pressure, O2 saturation, and pH at 40 °C were lower than those at 20 and 30 °C. Arterial CO2 partial pressure at 40 °C was higher than that at 20 and 30 °C. No differences were observed in arterial-mixed venous O2 concentration difference (P=0.391) and plasma lactate concentration (P=0.134) at different ambient temperatures. These results indicate that exercise at 40 °C causes excessive high body temperature, decreased running economy, and increased cardiac output compared to exercise at 20 and 30 °C. We strongly suggest that trainers and veterinarians should anticipate the occurrence of increased thermal stresses when ambient temperature is extremely high even in dry conditions and prepare to mitigate the risk of EHI from the perspective of equine welfare.

Clinical, biochemical, and histopathological diagnosis of Egyptian paediatric patients with suspected mitochondrial diseases: A hospital‑based study

Background. Mitochondrial respiratory chain (RC) disorders are a growing group of disorders with a large variety of clinical presentations ranging from well-defined clinical syndromes to nonspecific manifestations, such as failure to thrive, exercise intolerance and seizures.Objective. To describe the clinical, biochemical, and histochemical spectrum of 38 Egyptian patients clinically suspected of havingmitochondrial RC disorders.Methods. A total of 38 patients (female, n=18 (47.4%); male, n=20 (52.6%)) clinically suspected of having mitochondrial diseases had been referred to the Inherited Metabolic Diseases Laboratory at Cairo University Children’s Hospital. Laboratory investigations and analyses included histochemical staining of cytochrome c oxidase and succinate dehydrogenase in muscle biopsies, as well as spectrophotometric assays of RC complexes in muscle homogenates.Results. Twenty-three patients (60.5%) were diagnosed with different RC enzyme deficiencies. Fifteen patients (65%) had complex Ideficiency and all of them also had lactic acidosis (mean (standard deviation)) plasma lactate concentration of 4 (1.65) mmol/L). Twopatients (9%) with marked complex IV deficiency both showed COX-negative ragged red fibers (RRFs) on histochemical staining.Combined complex I and complex II deficiency with scattered COX-stain deficiency and RRFs was diagnosed in 2 patients (5.25%), whilea further 2 patients (5.26%) had combined (complex I, II+III, complex IV) deficiencies. Isolated complex II deficiency was diagnosed in2 patients (5.26%) and 15 (39.5%) patients had normal RC enzyme activities.Conclusion. Biochemical assay of RC complexes is considered the cornerstone for diagnosis of RC complex mitochondrial disorders.These disorders are common among Egyptian paediatric patients.

Maternal Dietary Carbohydrate Restriction and Mild-to-Moderate Exercise during Pregnancy Modify Aspects of Fetal Development in Rats

To determine whether acute bouts of exercise during pregnancy would predispose the fetus to increased risk if maternal dietary carbohydrate were restricted, untrained pregnant rats were randomly assigned to a 0% (low), 12% (moderate) or 60% (high) glucose diet, and either rested or exercised daily for 20 min from d 16 to term on a rodent treadmill at a mild (15.5 m/min) or moderate (24.3 m/min) intensity. A 3 ՠ3 nested factorial model with and without food intake as a covariate was employed. Both greater exercise intensity and the lower levels of dietary carbohydrate independently decreased term maternal liver and plantaris glycogen concentrations and increased plasma lactate concentrations. However, significant differences due to exercise disappeared (except for plasma lactate) with food intake controlled for in the model, indicating that energy deficits modulated these exercise effects. In contrast, for the offspring, when food intake was controlled for, a restricted level of maternal dietary carbohydrate significantly lowered fetal weight, plasma glucose and insulin concentrations and liver glycogen concentrations measured at term. Exercise alone did not reduce mean fetal weight if nested weights within a litter were used in the statistical analysis. Mild to moderate maternal exercise lowered only fetal plasma glucose concentrations and only if maternal food intake was not controlled for. These results indicate that acute exercise during pregnancy can have detrimental effects on fetal development only if dietary glucose is severely restricted. Otherwise, adequate glucose and energy in the maternal diet in untrained pregnant rats during repeated bouts of acute exercise seem to protect the fetus.

Feeding Status Affects Glucose Metabolism in Exercising Horses

Four standardbred horses were used in a Latin square design experiment to evaluate the effects of feeding status on metabolic response to exercise. Horses were deprived of food overnight and then fed 0 (control condition), 1, 2 or 3 kg of corn grain approximately 2.5-3 h before exercise. The exercise test consisted of a warm-up phase (heart rate mean = 144 beats/min) followed by 800 m of walking and then a high intensity work bout for 1600 m (heart rate mean = 206 beats/min). All tests were conducted on a high speed equine treadmill on which the horses had been previously conditioned. During exercise, the control treatment resulted in steady plasma glucose concentrations, whereas all other treatments (1, 2 or 3 kg corn) caused a decline in plasma glucose. Liver glycogen concentration was decreased by exercise in the horses only when they received the control treatment. Plasma lactate concentration was increased by exercise but was not affected by feeding state. Plasma free fatty acid concentrations were highest when the horses received the control treatment. In addition, when horses received the control treatment, plasma free fatty acid concentrations decreased during the warm-up and high intensity phases of the test and increased during the walk phase. Free fatty acid concentrations changed in the horses receiving 1, 2 or 3 kg of corn grain only during the high intensity phase of the exercise test. Feeding status affects the metabolic response of horses to exercise thus further studies are necessary to evaluate the effect of feeding status on exercise performance.

Longitudinal Training and Workload Assessment in Young Friesian Stallions in Relation to Fitness: Part 1.

Friesian stallions have to complete a 10-week studbook approval test (70-day test) consisting of dressage and driving training for acceptance as a breeding stallion. Training response of the horses to this approval program was evaluated. External workload (EW) of 16 stallions (3.2 ± 0.4 years old) was registered during the 9 weeks preceding the 70-day test (preparation period) and during 70-day test. Ridden indoor standardized exercise tests (SET), measuring heart rate (HR) and plasma lactate concentration (LA) at walk, trot and canter, were performed in week 1 (SET-I), 6 (SET-II) and 10 (SET-III) of the 70-day test. Linear mixed effect models were used to analyze HR and LA related to SETs and EW related to the phase of the study, using Akaike's information criterion for model reduction. EW was higher in the 70-day test compared to the preparation period, with longer duration of training sessions. Compared to SET-I, horses showed increased HR and LA after canter in SET-II and SET-III, indicating that they were more fatigued. The fact that the fitness of these Friesian stallions decreased during the 70-day test suggests overtraining. To optimize training effects and welfare of these horses, the workload of the training program needs to be adjusted.

Longitudinal Training and Workload Assessment in Young Friesian Stallions in Relation to Fitness, Part 2-An Adapted Training Program.

Young Friesian stallions have to complete a 10-week training program (70-day test) for acceptance as a breeding stallion. Part one of this study showed that the 70-day test was too intense and led to reduced fitness. In the present (part two) study, the effects of an adapted training program were studied. Training frequency and minutes of cantering per week were lowered compared with part one. The external workload (EW) of sixteen stallions (3.4 ± 0.8 years) was monitored during the 6-weeks before testing (preparation period) as well as during the 70-day test. Standardized exercise tests (SETs) were performed in week 1 (SET-I), 6 (SET-II), and 10 (SET-III) of the 70-day test, measuring heart rate (HR) and plasma lactate concentration (LA). Linear mixed effect models were used to analyze the EW, and the HR and LA related to the SETs. The EW increased from the preparation period to the 70-day test; this increase in the EW was lower compared with the original training program. The horses showed lower HR and LA levels in SET-III compared with SET-I. The young Friesian horses were at risk to be overtrained in part one, but the adapted training program resulted in increased fitness. This study shows that a carefully chosen program is necessary to improve the performance and welfare of (young) horses.

Management of acute mesenteric ischaemia: Results of a worldwide survey

Acute mesenteric ischaemia (AMI) is a condition with high mortality. This survey assesses current attitudes and practices to manage AMI worldwide. A questionnaire survey about the practices of diagnosing and managing AMI, endorsed by several specialist societies, was sent to different medical specialists and hospitals worldwide. Data from individual health care professionals and from medical teams were collected. We collected 493 individual forms from 71 countries and 94 team forms from 34 countries. Almost half of respondents were surgeons, and most of the responding teams (70%) were led by surgeons. Most of the respondents indicated that diagnosis of AMI is often delayed but rarely missed. Emergency revascularisation is often considered for patients with AMI but rarely in cases of transmural ischaemia (intestinal infarction). Responses from team hospitals with a dedicated special unit (14 team forms) indicated more aggressive revascularisation. Abdominopelvic CT-scan with intravenous contrast was suggested as the most useful diagnostic test, indicated by approximately 90% of respondents. Medical history and risk factors were thought to be more important in diagnosis of AMI without transmural ischaemia, whereas for intestinal infarction, plasma lactate concentrations and surgical exploration were considered more useful. In elderly patients, a palliative approach is often chosen over extensive bowel resection. There was a large variability in anticoagulant treatment, as well as in timing of surgery to restore bowel continuity. Delayed diagnosis of AMI is common despite wide availability of an adequate imaging modality, i.e. CT-scan. Large variability in treatment approaches exists, indicating the need for updated guidelines. Increased awareness and knowledge of AMI may improve current practice until more robust evidence becomes available. Adherence to the existing guidelines may help in improving differences in treatment and outcomes.

Supplementation of palmitoleic acid improved piglet growth and reduced body temperature drop upon cold exposure

Abstract Piglet survival is a major challenge in the first few days postpartum and interventions during this period may improve survival and growth. This study investigated the effects of palmitoleic acid (C16:1n-7; PA) supplementation on growth performance, body temperature, fatty acid (FA), and energy metabolism in milk-replacer-fed piglets. Forty-eight piglets were stratified by body weight and randomly assigned to one of four dietary treatments (0%, 1%, 2%, and 3% PA supplementation as a percent of milk replacer) and given the diet through an orogastric tube. They were fed dietary treatments every 2 h for 4 d in the first week postpartum and all were sacrificed at the end of the experiment. The piglets were weighed daily, and half in each dietary treatment group, the same piglets each day, were exposed daily to a lower temperature for 2 h. Plasma samples were collected immediately before sacrifice for analyses of FA and other plasma metabolites. The weight of organs and empty body weight were determined after sacrifice. Liver and semimembranosus muscle tissue samples were collected and analyzed for FA content. Contents of C16:1n-7 and C18:1n-7 in both plasma and liver (P &amp;lt; 0.001), and C16:1n-7 in semimembranosus muscle (P &amp;lt; 0.001) increased linearly as PA supplementation increased. Most plasma FA levels (except C16:1n-7, C16:1n-9, and C22:5n-3) were lower in piglets exposed to lower temperatures than those that were not. Plasma glucose, triglycerides, and lactate dehydrogenase levels increased linearly with PA supplementation (P &amp;lt; 0.001). Piglets’ average daily gain, liver glycogen pool, liver weight, and gallbladder weight increased linearly (P &amp;lt; 0.05, P &amp;lt; 0.01, P &amp;lt; 0.05, and P &amp;lt; 0.001, respectively), but lung weight, liver nitrogen content, and body temperature drop decreased linearly (P &amp;lt; 0.01, P &amp;lt; 0.001, and P &amp;lt; 0.05, respectively) with PA supplementation. Piglets exposed to low temperature had greater liver nitrogen (P &amp;lt; 0.05) and lactate dehydrogenase (P &amp;lt; 0.001) contents but had lower liver weight (P &amp;lt; 0.01) and plasma lactate concentration (P &amp;lt; 0.05) than those that were not. In conclusion, this study demonstrated the importance of PA on the growth performance of the piglets by increasing their average daily gain and decreasing a drop in body temperature upon cold exposure, most likely due to a modified energy metabolism.

Utility of the National Emergency Laparotomy Audit prognostic model in predicting outcomes in an Australian health system.

The Royal College of Anaesthetists was commissioned by the United Kingdom Health Quality Partnership to conduct the National Emergency Laparotomy Audit of England and Wales (NELA), to compare outcomes of patients undergoing emergency laparotomy in order to promote quality improvement. Prior to 2016 there were minimal data for emergency laparotomy patients in Australia. The aim of this cohort study was to assess the utility and applicability of the NELA model in a tertiary centre in Western Australia. NELA-related data of patients who underwent emergency laparotomy, between June 2018 and May 2020, were merged with other administrative databases and clinical records. The discriminative ability and calibration of the model were assessed by the area under the receiver operating characteristic (AUROC) curve and calibration plot, respectively. Cox proportional hazards regression was used to assess whether the NELA-predicted risks were an independent predictor of hospital mortality. Of the 502 patients included, 168 (33.5%) patients had a NELA-predicted risk >10%, and of these, 93 (55.4%) were admitted to a critical care unit in a planned fashion immediately after surgery. The NELA model had a good ability to discriminate between survivors and non-survivors (AUROC 0.892, 95% confidence intervals 0.854 to 0.93, P <0.001). However, the model was not perfectly calibrated, with the predicted risks tending to overestimate the observed risks of mortality, especially when the predicted risks were >50%. A high NELA-predicted risk remained significantly associated with mortality after adjusting for other covariates, including sepsis and plasma lactate concentration, suggesting that it is a reliable screening tool for identifying high-risk patients requiring emergency laparotomy.

Impact of Lower Airway Inflammation on Fitness Parameters in Standardbred Racehorses.

Mild-moderate equine asthma (MEA) is a common respiratory disorder among racehorses, characterized by lower airway inflammation. Although it is generally agreed that MEA causes poor performance, contrasting results have been reported about the effects of tracheal mucus and the leukocyte populations of the bronchoalveolar lavage (BAL) on performance. This study aims to investigate the associations between airway inflammation and fitness parameters measured during an incremental treadmill test on Standardbred racehorses. For this purpose, the clinical records of 116 Standardbreds subjected to a diagnostic protocol for poor performance were retrospectively reviewed. Parametric and nonparametric statistics were used to evaluate the relationships between endoscopic scores, BAL cytological results, and fitness parameters. Moreover, horses were divided into MEA and non-MEA groups and into neutrophilic, eosinophilic-mastocytic, and mixed MEA groups; fitness parameters were compared between groups. Neutrophils percentages were inversely correlated with the speed at a heart rate of 200 bpm, the speed and heart rate at a plasma lactate concentration of 4 mmol/L (VLa4 and HRLa4), and the maximal speed, while they were positively correlated with higher lactate concentrations. Moreover, significant differences were detected between different MEA subtypes concerning VLa4, HRLa4, and lactate concentrations. These results suggest that airway neutrophilic inflammation impairs athletic capacity in Standardbreds.

Effects of Salinity and Dissolved Oxygen Concentration on the Tail-Flip Speed and Physiologic Response of Whiteleg Shrimp, Litopenaeus vannamei

The swimming ability of shrimp is important for their survival and growth, which directly affects their avoidance of enemies and uncomfortable environment, search and capture of food, reproductive behavior, and distribution. The knowledge concerning the swimming ability of shrimp can be widely used in the conservation of fishery resources, improving capture efficiency and stock enhancement. As one of the edible marine organisms, Litopenaeus vannamei is a traditional fishery resource and an important economic aquaculture species in China. Dissolved oxygen (DO) concentration and salinity are considered to play crucial roles in the swimming ability of L. vannamei. The tail-flip speed (Stf) of whiteleg shrimp L. vannamei (79.90 ± 0.41 mm, 5.76 ± 0.10 g) that were exposed to various salinities (20‰, 25‰, 30‰, 35‰, and 40‰) and DO concentrations (1.9, 3.8, 6.8, and 13.6 mg/L) was determined under laboratory conditions. Metabolite concentrations in the hemolymph, hepatopancreas, and abdominal muscles were measured before and after tail-flip fatigue to evaluate the physiologic effects of fatigue in L. vannamei. The results showed that salinity and DO significantly affected the Stf of L. vannamei. The Stf increased and subsequently decreased with the increase in salinity from 20‰ to 40‰. The relationship between Stf and salinity (s, ‰) can be expressed by the quadratic model as Stf = −0.2386s2 + 15.528s − 145.12, R2 = 0.9693. The optimum salinity and corresponding maximum Stf were 32.54‰ and 107.52 cm/s, respectively. The Stf increased as the DO concentration increased from 1.9 mg/L to 13.6 mg/L. The relationship between Stf and DO (mg/L) can be expressed by the power model as Stf = 75.621 DO0.1753, R2 = 0.9981. The different salinities and DO concentrations directly affected the physiology of the shrimp, inducing changes in hepatopancreas total protein, plasma total protein, abdominal muscle lactate, plasma lactate, plasma glucose, hepatopancreas glycogen, and abdominal muscle glycogen concentration. Fatigue from tail-flip led to severe loss of hepatopancreas glycogen under 20‰ salinity and plasma glucose under 25‰, 30‰, and 35‰ salinity. The triglyceride and lactate in the plasma concentration increased significantly in a range of salinities. In the DO concentration experiment, fatigue from tail-flip led to a severe loss of plasma glucose under 1.9 mg/L and 3.8 mg/L DO concentrations. The plasma lactate concentration increased significantly in all DO groups. The results suggested that the inappropriate salinity and DO significantly limited the tail-flip speed of shrimp, which was due to the accumulation of metabolites. The proper salinity and DO accelerated the elimination of metabolites, reduced the energy consumption of shrimp, and thus, improved the exercise ability of shrimp. This conclusion is of particular value in evaluating the swimming ability of shrimp and understanding its ecological processes to improve capture and rearing techniques.

Optimization of a Single Substrate-Based Fluorometric Assay for Glucose and Lactate Measurement to Assess Preimplantation Single Embryo Quality and Blood in Obese Mouse and Clinical Human Samples.

A fluorometric assay for single substrate-based glucose and lactate measurements was demonstrated by adopting an already established protocol for glucose and by optimizing pH, enzyme concentration, substrate concentration, and types of buffers for lactate. Linear calibration curves for glucose and lactate concentrations from 1 to 100 μM were obtained with correlation coefficients (R2) of 0.94 and 0.98, respectively. First, with the optimized protocol, single embryo quality was successfully evaluated. Three different initial stages of embryos (n = 58) were cultured for 24 h, and glycolytic activities were calculated by measuring amounts of glucose consumption and lactate production. Results showed that embryos cultured at a later stage had lower glycolytic activities, implying more developmental activities. Second, glucose and lactate concentrations in blood plasma of diet-induced obese (DIO) mice were measured. Levels of both glucose and lactate in DIO mice were higher than those in normal mice by 2.15 and 3.8 mmol/L, respectively (both p < 0.001). Finally, clinical serum samples were analyzed and categorized into three groups based on their measured glucose concentrations: normal (4.73 ± 0.29 mmol/L), prediabetic (6.49 ± 0.13 mmol/L), and diabetic (11.34 ± 1.36 mmol/L) (p < 0.05). Collectively, this developed technique can be used to select a high-quality embryo for transfer as well as to measure glucose and lactate levels in other biological samples.

Using whole cottonseed to replace dried distillers grains plus solubles and prairie hay in finishing beef cattle rations balanced for physically effective neutral detergent fiber

The objective of this experiment was to determine the effects of replacing prairie hay and dried distillers grains plus solubles with whole cottonseed (WCS) in diets balanced for physically effective NDF on the growth, intake, feed efficiency, carcass characteristics, and plasma metabolites of finishing beef cattle. Crossbred heifers (n = 103) and steers (n = 104) were blocked by BW within sex and randomly allocated to pens within block (6 pens per treatment) with 17 (n = 10 pens) or 18 (n = 2 pens) animals per pen. Pens were randomly allocated to experimental treatment: either a control diet (CON; prairie hay, dried distillers grains plus solubles, dry-rolled corn, and liquid supplement) or a WCS diet (CTN; WCS, dry-rolled corn, and molasses). A common vitamin and mineral supplement and urea were included in both diets at the same rate. Animals were slaughtered in 3 groups based on BW block. Cattle fed the CTN treatment tended to have a greater final BW (P = 0.10) and had greater overall ADG and G:F (P ≤ 0.05). There was no difference in overall DMI (P = 0.23). Fecal consistency scores were greater for cattle fed the CON treatment on d 42, at the beginning of the β-agonist feeding period, and at the final collection before slaughter (P ≤ 0.03). Cattle fed the CTN treatment had a more neutral fecal pH on d 140 and at the final collection (P < 0.01). No treatment × day interactions (P ≥ 0.70) were detected for plasma glucose, lactate, urea nitrogen, or nonesterified fatty acid concentrations. Cattle fed the CON treatment had greater plasma urea nitrogen concentrations (P < 0.001) and a tendency for a greater plasma lactate concentration (P = 0.06). A day effect was also observed for all plasma metabolites (P < 0.001). This experiment suggests that feeding WCS improves the growth and feed efficiency of cattle when replacing the roughage and byproduct protein and fat sources within a finishing diet.

English

Over the years, the search for nutritional strategies that promote improved sports performance has increased. Among the available options, energy drinks appear as potential nutritional resources for this purpose, because they offer, in addition to caffeine, substances that act synergistically to improve performance, such as taurine, carbohydrates, amino acids, vitamins and minerals, promoting improved performance for both amateur and professional athletes. The aim of the study was to verify the effects of ingesting energy drinks with (ED1) and without carbohydrates (ED0) containing 2 mg·kg-1 of caffeine, and a decaffeinated placebo (PL) on cardiovascular, metabolic and performance parameters during cycling. Twelve male cyclists (age = 24.4 ± 6.6 years old) volunteered to participate in this study. The protocol consisted of three experimental sessions of 60 min of continuous cycling (65-75% of VO2maxE) followed by time-trial 6 km. The subjects ingested ED1, ED0 or a placebo drink (PL) 40 min before beginning the exercise. The heart rate (HR), blood pressure (BP), plasma glucose and lactate concentrations, and the time taken to complete the 6 km time-trial were evaluated. The time taken to complete the time-trial was significantly higher (p &lt; 0.05) in the PL group than in the groups ED1 and ED0. This time significantly decreased after the ED1 consumption relative to that for the ED0 consumption. Heart rate, systolic and diastolic arterial pressure and in the plasma glucose and lactate concentrations were similar in all the considered groups. These results demonstrate that ED1 consumption appears to be more effective at maximizing performance during the last 6 km.