Skeletal muscle characteristics in young trained and untrained standardbred trotters.

Muscle biopsies were taken from the middle gluteal muscle of 28 Standardbred trotters, 3-4 years of age. The 13 horses in Group T were trained consistently from 18 months of age, whereas the 15 horses in Group UT were not exposed to any systematic training before 3 years of age. Group T horses had a lower percentage of Type IIB fibres (31%) than did Group UT horses (39%). Citrate synthase (CS) activity, representing oxidative capacity, was higher in Group T (72 mmol kg-1 min-1) than in Group UT (47 mmol kg-1 min-1). Biopsies were taken from 4 horses in each group when they were foals and then annually until 3-4 years of age. Results from this study indicate that regular training of Standardbreds from 18 months of age resulted in increased CS activity and a decrease in the percentage of Type IIB fibres. This study shows that training, not growth, is the main factor that induces a high oxidative capacity and a high Type IIA/IIB fibre ratio in muscle of Standardbred trotters.     

Chronic partial obstructive urolithiasis causing hydronephrosis and chronic renal failure in a steer.

A 13-month-old Angus steer was examined with a 6-week history of lethargy, malaise and dribbling urine. Laboratory exam revealed crystalluria and poor renal function. Ultrasound revealed hydronephrosis and hydroureter. Euthanasia was chosen because of a poor prognosis for economic recovery. Necropsy demonstrated numerous calculi causing partial urethral obstruction approximately 25 cm from the end of the penis. Secondary renal changes were confirmed. Urolithiasis occurs commonly in ruminants. Secondary obstruction is usually complete with severe consequences. This is the first report of chronic partial obstructive urolithiasis resulting in endstage renal disease.     

Ruminal biohydrogenation of fatty acids from high-oleate sunflower seeds.

The objective of these experiments was to examine methods of modifying the fatty acid composition of bovine tissues. In the first experiment, four steers were fitted with duodenal fistulas and were assigned to four diets in a Latin square design. The steers were fed a control diet or the same diet containing 10% high-oleate partially crushed sunflower seeds, serum-coated sunflower seeds, and heat-treated, serum-coated sunflower seeds for 5 d. Samples of digesta and feces were collected on d 5. The inclusion of sunflower seeds (plain or serum-coated) in the diet increased (P less than .05) the digesta concentration of stearate. The percentage of stearate in the digesta and feces was increased (P less than .05) from 51 to 67% and from 64 to 74%, respectively, when steers were fed the untreated sunflower seed. The fecal concentration of oleate was increased (P less than .05) by dietary sunflower seeds in steers that were fed the serum-coated, unheated sunflower seeds. In a second experiment, heifers (four per group) were fed a corn-based control diet or diets containing 10% of high-oleate sunflower oil encapsulated with calcium alginate, either plain, coated with blood meal, or with blood meal integrated into the pellet. After 50 d on treatment, samples of perianal adipose tissue were obtained by biopsy. The fatty acid composition of the adipose tissue was not modified by the inclusion of the encapsulated oleate in the diet. In summary, limited ruminal bypass of sunflower seed oleate was accomplished with sunflower seed but not with encapsulated oleate.     

Fractionation of cock spermatozoa

An account is given of the methodology for fractionation of cock spermatozoa into head and tail fractions by ultrasonication, followed by sucrose density gradient centrifugation. Quantitative estimates of DNA attested to 89.4% purity of the head fraction and low contamination of tails with heads. Recovery of protein and malic dehydrogenase (MDH) activity, following sperm fractionation, averaged 94.3% and 95.7%, respectively. Contamination of the head fraction with tails, as assessed by MDH assay, was only 4.65%, and the purity of the tail fraction was 91%. Intensive succinic dehydrogenase (SDH) activity was histochemically localised in the separated tail fraction and in the tail portion of intact spermatozoa. However, SDH activity was discernible neither in the head fraction nor in the head of intact spermatozoa.     

Acute selenium toxicosis in a dog

A toxic dose of selenium administered by IM injection to a 3-year-old Chihuahua resulted in pulmonary edema and death. The compound had been dispensed to the owner inadvertently in combination with a vitamin E preparation. Vitamin and mineral products often are considered safe for use in megadoses by the uninformed public. The potential danger of selenium overdosage should not be underestimated.     

Insulin-like growth factor I receptor analysis of satellite cell-derived myotube membranes established from two lines of Targhee rams selected for growth rate

Ovine-derived fibroblasts were used to validate an insulin-like growth factor I (IGF-I) membrane-receptor binding assay system. Competitive binding using fibroblasts revealed that half-maximal inhibition of 125I-IGF-I binding by IGF-I was 2.3 nM. SDS-polyacrylamide gel electrophoresis analysis of specific protein-associated 125I-IGF-I was consistent with the migration of 125I-IGF-I-labeled Type I IGF receptor alpha-subunits at Mr 133,000 daltons. Further, the efficiency of two cell solubilization methods was examined and time-dependent binding equilibrium was determined for the membrane assay system. Satellite cell-derived myotubes were subsequently isolated from primary satellite cell cultures established from the semimembranosus muscles of high and low efficiency-of-gain (EOG) Targhee rams, and IGF-I receptor dynamics were measured. A membrane competitive binding study revealed that half-maximal inhibition of 125I-IGF-I binding was achieved by 1-ng IGF-I for low, and 10-ng IGF-I for high, EOG myotube membrane preparations. Kd values were similar between the high EOG (4.78 nM) and low EOG (2.95 nM) groups; however, receptor concentrations (Bmax) appeared to differ between groups. High EOG membrane receptor Bmax was 3.88 pmole/micrograms protein (19.87 pmole/micrograms DNA), whereas low EOG membrane receptor Bmax was 1.22 pmole/micrograms protein (9.28 pmole/micrograms DNA). These preliminary findings support the hypothesis that genetic selection for EOG results in altered satellite cell responsiveness to IGF-I.     

Infectious load of Aeromonas salmonicida subsp. salmonicida during the initial phase of a cohabitant infection experiment with Atlantic salmon, Salmo salar L.

Abstract The abundances of Aeromonas salmonicida subsp. salmonicida in the water and in the surface microlayer was studied during the initial phase of a cohabitant infection experiment with Atlantic salmon, Salmo salar L., smolt. Aeromonas salmonicida was detected in the water samples only until the intraperitoneally infected smolt were dead and had been removed. In the lipid rich surface microlayer, A. salmonicida was detected in high concentrations from the day of the first fish mortality and throughout the rest of the experiment. The significance of the high cell surface hydrophobicity is discussed as a possible reason for enrichment of A. salmonicida at the air-water interface.     

Use of 64Copper Measurements to Diagnose Canine Copper Toxicosis

Inherited canine copper toxicosis is a serious problem in Bedlington terriers and West Highland White terriers, and may also be a problem in other less-studied breeds. Affected dogs become ill at midlife with progressive and ultimately fatal liver disease. Treatments for removal of copper and prevention of copper accumulation are available, but are most effective if begun before the dog becomes ill. Until recently diagnosis has not been available until the dog is 1 year of age, and then only by an invasive liver biopsy with determination of liver copper concentration. The authors studied the use of 64copper for early diagnosis of canine copper toxicosis. Two procedures were evaluated. The first involved measuring the concentration of 64copper in blood 24 hours after oral administration of the radioisotope. At this time, 64copper was associated primarily with ceruloplasmin secreted into the blood by the liver. This procedure is useful in the diagnosis of the human counterpart, Wilson's disease. However, the authors found it to be nondiscriminatory between affected and unaffected dogs. In contrast, the second procedure, which involved measuring 64copper excreted in stool during 48 hours after an intravenous dose of radioisotope, yielded results that differentiated most affected and unaffected dogs.     

Oral fowlpox vaccination in chickens.

Chickens were given various fowlpox vaccines on food pellets--a commercial vaccine (strain M), and the same strain after a single passage on chorio-allantoic membrane or in chicken embryo fibroblasts. All three oral vaccines induced antibodies at levels similar to those induced by commercial strain M administered to the wingweb. The oral vaccine derived from chorio-allantoic membrane gave protection similar to that obtained with vaccine administered by the wingweb, but this required a thousandfold more virus.