Introduction: Glycolic changes which occur post-mortem have an impact on the physical and sensory features of beef, which in turn determine the successive processes and influence such beef quality traits as colour, tenderness, and cooling loss. The aim of this study was evaluation of the post-mortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic acid, as well as examination of their impact on technological and sensory quality of selected muscles from Holstein-Friesian × Limousin breed carcasses.

Dogs with chronic kidney disease (CKD) may have alterations in the glomerular filtration barrier, including podocyte loss. Detection of podocyte mRNA in urine could be useful for assessing podocyturia in dogs with kidney disease. The objective of this study was to evaluate the presence of nephrin mRNA (NPHS1) and podocin mRNA (NPHS2) in urine sediments of dogs with naturally occurring CKD and healthy dogs. Twenty-four dogs, 14 with CKD and 10 as healthy controls, underwent clinical evaluation. The dogs with CKD were divided into two groups, according to the International Renal Interest Society criteria: stage 1 or 2 CKD (n = 5) and stage 3 or 4 CKD (n = 9). Urine was collected by catheterisation or free catch and RNA isolation from the urine sediments was optimised using glycogen as a co-precipitant. Detection of NPHS1 and NPHS2 in the sediment samples was performed using quantitative real-time PCR. Both types of mRNA were detected in samples from all groups, but the percentages of detection were higher in the group of dogs with stage 1 or 2 CKD and lower in the group of dogs with stage 3 or 4 disease. Physiological podocyturia was observed in healthy dogs, and the results suggest differential podocyturia in dogs with CKD, according to the stage of the disease, i.e. an increase in podocyturia in dogs at stage 1 or 2 and a reduction in podocyturia in dogs at stage 3 or 4.

Introduction: Glycolic changes which occur post-mortem have an impact on the physical and sensory features of beef, which in turn determine the successive processes and influence such beef quality traits as colour, tenderness, and cooling loss. The aim of this study was evaluation of the post-mortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic acid, as well as examination of their impact on technological and sensory quality of selected muscles from Holstein-Friesian × Limousin breed carcasses.Material and Methods: The study included three muscles of different metabolic qualities and sarcomere length: m. semitendinosus, m. longissimus dorsi, and m. psoas major, collected from nine bull carcasses aged 24 ±2 months.Results: Significant correlations were found between the volume of cooling loss on individual days of aging and the pH value of muscle tissue, lactic acid and glycogen content, as well as beef lightness. However, no significant dependency between the volume of glycogen and the intensity of red and yellow colours was detected.Conclusion: The colorimetric analysis of glycogen and lactic acid can be an effective tool in predicting the quality of beef.

OBJECTIVE To characterize clinical findings for polysaccharide storage myopathy (PSSM) in warmblood horses with type 1 PSSM (PSSM1; caused by mutation of the glycogen synthase 1 gene) and type 2 PSSM (PSSM2; unknown etiology). SAMPLE Database with 3,615 clinical muscle biopsy submissions. PROCEDURES Reported clinical signs and serum creatine kinase (CK) and aspartate aminotransferase (AST) activities were retrospectively analyzed for horses with PSSM1 (16 warmblood and 430 nonwarmblood), horses with PSSM2 (188 warmblood and 646 nonwarmblood), and warmblood horses without PSSM (278). Lameness examinations were reviewed for 9 warmblood horses with PSSM2. Muscle glycogen concentrations were evaluated for horses with PSSM1 (14 warmblood and 6 nonwarmblood), warmblood horses with PSSM2 (13), and horses without PSSM (10 warmblood and 6 nonwarmblood). RESULTS Rhabdomyolysis was more common for horses with PSSM1 (12/16 [75%] warmblood and 223/303 [74%] nonwarmblood) and nonwarmblood horses with PSSM2 (221/436 [51%]) than for warmblood horses with PSSM2 (39/147 [27%]). Gait abnormality was more common in warmblood horses with PSSM2 (97/147 [66%]) than in warmblood horses with PSSM1 (1/16 [7%]), nonwarmblood horses with PSSM2 (176/436 [40%]), and warmblood horses without PSSM (106/200 [53%]). Activities of CK and AST were similar in warmblood horses with and without PSSM2. Muscle glycogen concentrations in warmblood and nonwarmblood horses with PSSM1 were significantly higher than concentrations in warmblood horses with PSSM2. CONCLUSIONS AND CLINICIAL RELEVANCE Rhabdomyolysis and elevated muscle glycogen concentration were detected in horses with PSSM1 regardless of breed. Most warmblood horses with PSSM2 had stiffness and gait abnormalities with CK and AST activities and muscle glycogen concentrations within reference limits.

OBJECTIVE To characterize the postprandial nutrient profiles of exercise-conditioned dogs fed a supplemental carbohydrate and protein bar with or without astaxanthin from Haematococcus pluvialis immediately after exercise. ANIMALS 34 exercise-conditioned adult Husky-Pointer dogs. PROCEDURES The study had 2 phases. During phase 1, postprandial plasma glucose concentration was determined for dogs fed a bar containing 25% protein and 18.5% or 37.4% maltodextrin plus dextrin (rapidly digestible carbohydrate; RDC), or dry kibble (30% protein and 0% RDC) immediately after exercise. During phase 2, dogs were exercised for 3 days and fed a bar (25% protein and 37.4% RDC) with (CPA; n = 8) or without (CP; 8) astaxanthin or no bar (control; 8) immediately after exercise. Pre- and postexercise concentrations of plasma biochemical analytes and serum amino acids were determined on days 1 and 3. RESULTS Phase 1 postexercise glucose concentration was increased when dogs were provided the 37.4% RDC bar, but not 0% or 18.5% RDC. On day 3 of phase 2, the CPA group had the highest pre-exercise triglyceride concentration and significantly less decline in postexercise glucose concentration than did the CP and control groups. Mean glucose concentration for the CP and CPA groups was significantly higher than that for the control group between 15 and 60 minutes after bar consumption. Compared to immediately after exercise, branched-chain amino acid, tryptophan, leucine, and threonine concentrations 15 minutes after exercise were significantly higher for the CP and CPA groups, but were lower for the control group. CONCLUSIONS AND CLINICAL RELEVANCE Dogs fed a bar with 37.4% RDCs and 25% protein immediately after exercise had increased blood nutrient concentrations for glycogen and protein synthesis, compared with control dogs.

The size and quality of muscle specimens obtained by use of a percutaneous biopsy technique were studied. All biopsies were performed under local anesthesia, using an 11-gauge biopsy needle. The mean +/- SEM size of specimens obtained from 128 biopsies of the semitendinosus muscles of 16 Alaskan Huskies was 23.8 +/- 4.4 mg. All biopsy specimens were of sufficient quality to permit histochemical differentiation of the fiber types by use of myosin ATPase staining. An additional 8 biopsy specimens were obtained from 1 dog and analyzed for muscle glycogen content. These specimens contained 50.6 +/- 7.2 mmol of glucose/kg of muscle wet weight. This modified biopsy procedure was free of notable complications, and repeatable use produced specimens of adequate size and quality for histologic and biochemical analysis. It is concluded that this procedure is a safe and reliable alternative to open biopsy for diagnosis and management of neuromuscular, metabolic, and nutritional myopathies.

Ten healthy sedentary Thoroughbreds with previous race training experience were trained conventionally for 9 weeks. Muscle biopsy samples were obtained before and after training and after 6 weeks of detraining pasture rest. Biopsy samples were obtained from the right deltoid, triceps, vastus lateralis, middle gluteal, biceps femoris, and semitendinosus muscles. The deep-frozen biopsy samples were analyzed for activities of succinate dehydrogenase (SDH), 3-hydroxy-acylcoenzyme A dehydrogenase (HAD), and phosphorylase (PHOS) and for glycogen concentration. The triceps and gluteal muscle samples were also serially sectioned and stained for myofibrillar actomyosin adenosine triphosphatase (ATPase) activity after alkaline (pH 10.3) and sequential acidic (pH 4.34) ATPase inactivation. Fiber types I (alkaline preincubation), IIA1, IIA2, and IIA3 (sequential acidic preincubation over 5 minutes) were identified and were evaluated for fiber-type distribution and fiber areas. Increases in response to training were observed in deltoid and vastus muscle SDH and gluteal muscle HAD activities, and deltoid muscle glycogen concentration (P < 0.05 to P < 0.01). Changes in PHOS activity were not observed. Type-IIA1, -IIA2, and -IIA3 fiber areas in triceps muscle were increased in response to training (P < 0.05 to P < 0.01). Changes in fiber-type distribution did not occur in response to training. Changes in muscle enzyme activities, glycogen concentration, fiber types, and fiber areas were not seen from posttraining to detraining. Further increases were observed when detraining values were compared with pretraining values in deltoid, triceps, vastus, gluteal, and biceps femoris muscle SDH activities and in gluteal muscle glycogen concentration (P < 0.05 to P < 0.01). It was concluded that the predominant failure to detect training-induced muscle enzyme changes, along with documentation of increases in fast-twitch muscle fiber areas, indicate that conventional Thoroughbred training is principally of a sprinting nature. A greater emphasis on longer, slow endurance work early in training might add greatly to Thoroughbred horses' abilities to withstand the rigors of sprint training.

Objective: To determine whether repeated oral administration of glucose and leucine during the period immediately after intense exercise would increase the release of insulin and thereby enhance glycogen synthesis in horses. Animals: 12 Standardbred horses. Procedures: In a crossover study design, after glycogen-depleting exercise, horses received oral boluses of glucose (1 g/kg at 0, 2, and 4 hours) and leucine (0.1 g/kg at 0 and 4 hours) or boluses of water (10 mL/kg at 0, 2, and 4 hours; control treatment). Blood samples for determination of glucose, insulin, and leucine concentrations were collected prior to and during a 6-hour period immediately after exercise. Biopsy specimens of a gluteus muscle were obtained before and immediately after exercise and at 3, 6, and 24 hours after exercise for measurement of glycogen concentration. Results: When glucose and leucine were administered to the horses, plasma insulin concentration was significantly higher during the 6 hours immediately after exercise than it was when water was administered to the horses. Serum glucose concentration during the 4 hours immediately after exercise was significantly higher when glucose and leucine were administered than the serum glucose concentration when water was administered. Muscle glycogen concentrations did not differ between the 2 treatments during the 24 hours after exercise. Conclusions and Clinical Relevance: Synthesis of muscle glycogen after intense intermittent exercise was not enhanced by oral boluses of glucose and leucine after exercise despite pronounced increases in plasma insulin and serum glucose concentrations.

Objective-To characterize insulin-sensitive glucose-transporter (GLUT-4) protein in equine tissues and determine effects of exercise and glucose administration on content of GLUT-4 protein in equine skeletal muscle. Sample Population-Tissue samples from 9 horses. Procedure-Western blot analyses were performed on crude membrane preparations of equine tissues to characterize GLUT-4. In a crossover, randomized study, horses were strenuously exercised for 3 consecutive days and then administered 13.5% glucose or isotonic saline (0.9% NaCl; control) solution, IV, at similar infusion rates for 12.1 hours. Samples were collected from the middle gluteal muscle before and after exercise and 10.1 hours after completion of an infusion and used for measurements of glycogen concentration and total content of GLUT-4 protein. Results-Immunoblot analyses detected specifically immunoreactive bands for GLUT-4 in insulin-sensitive tissues. Content of GLUT-4 protein in skeletal muscle increased significantly by 27.3 and 12.3% 22.2 hours after exercise for control and glucose groups, respectively. Intravenous infusion of glucose resulted in a significantly higher rate of glycogenesis, compared with results for the control group (mean +/- SD, 3.98 +/- 0.61 and 1.47 +/- 0.20 mmol/kg/h, respectively). Despite enhanced glycogenesis, we did not detect an increase in content of GLUT-4 protein after glucose infusion, compared with values after exercise. Conclusions and Clinical Relevance-GLUT-4 protein was expressed in equine skeletal and cardiac muscles. Exercise increased total content of GLUT-4 protein in skeletal muscle, and replenishment of muscle glycogen stores after glucose infusion attenuated the exercise-induced increase in the content of GLUT-4 protein in equine skeletal muscle.