The passage of nitrogenous compounds through the wall of perfused sheep rumen (author's transl)]

Experiments were performed by the method of the extracorporeal perfusion of sheep rumen lasting 150 minutes. After 60 minutes of perfusion, 20 g of enzymatic casein hydrolyzate were applied to the rumen. Ammonia, urea, and total nitrogen were determined in the samples of perfusate, and ammonia and pH were determined in the rumen content. Considerable amounts of ammonia accumulated in the perfusate in the course of the experiment. At the end of perfusion, the concentration of NH3-N reached an average value of up to 12 mg per 100 ml. The level of urea in the perfusate decreased only in the first phase of perfusion (before the application of casein hydrolyzate to the rumen) and remained unchanged in the subsequent phase. It is assumed that part of urea-N from the perfusate after urea hydrolysis, taking place already in the rumen wall, returned to the perfusate in the form of ammonia. In the first phase of perfusion the passage of nitrogen from the blood into the rumen took place, in the second phase its absorption from the rumen into the blood was observed. The urea-N ratio from the passage of total nitrogen into the rumen ranged between 4.63% and 13.84%, but the concentration of total nitrogen in the perfusate decreased by 7-15% and that of urea nitrogen by 37-42%. It follows from the results that a major part of endogenous nitrogen passing from perfusate to the rumen was represented by proteins and/or their peptidic splits.     

Isolation of Chlamydia psittaci and Moraxella bovis from infectious keratoconjunctivitis in lambs

Out of 189 lambs in the flock, 25 animals suffered from bilateral or unilateral conjunctivitis, or keratoconjunctivitis. By serological examination (RVK), positive levels of antibodies to the group-specific antigen of Chl. psittaci were found in three out of six lambs examined by laboratory methods. Bacteriological examination of eye smears of six lambs showed in four cases the infection by microorganisms of Moraxella bovis. Smears from the conjunctivas of these lambs were after preparation instilled in the yolk sacs of six to seven days old chicken embryos. One strain of Chlamydia psittaci was isolated from the same material as Moraxella bovis.     

Determination of zearalenone in grains using high pressure liquid chromatography

The determination of zearalenone content in cereals (maize, wheat and barley) was performed by means of liquid chromatography using the Czechoslovak-made apparatus. This method enables to determine this mycotoxin up to the concentration of 8 micrograms per 1 kg of grain with the accuracy exceeding +/- 9%.     

Ascorbic acid levels in the bronchopneumonia of calves]

The level of ascorbic acid in the blood plasma of 59 calves was determined. The age of the calves ranged between two and three months and the samples of blood were collected in January. The first group of calves included 30 animals displaying no clinical symptoms of disease: the average ascorbic acid level was 0.50 +/- 0.18 mg per 100 ml. In the second group, consisting of 19 calves, the blood of the animals was collected three weeks after the termination of the acute stage of bronchopneumonia; the average value of ascorbic acid was 0.30 +/- 0.14 mg per 100 ml. The lowest average value of ascorbic acid was obtained in the calves at an acute stage of bronchopneumonia, reaching 0.18 +/- 0.11 mg per 100 ml. The differences of results between groups I and II and between groups I and III were found to be statistically significant. A conspicuous drop of ascorbic acid level was ascertained in calves suffering from bronchopneumonia-this problem needs deeper scrutiny, owing to the fact that bronchopneumonia is responsible for considerable economic losses in large-capacity calf houses.     

Changes in biochemical indicators in the blood and organs of pigs fed dried grape press cake]

In two experiments the effect of feeding dried crushed white and red grape press cake replacing 10--20% of the complex feed mixture A1 and SOL, was studied on the 21 biochemical indicators of blood serum, plasma, suprarenal glands, liver and tissue of fattened pigs. Changes indicating unsuitability of this non-traditional feed were not observed. During feeding red grape press cake, the young pigs of 35kg body weight had a lower concentration of glucose in blood serum, in comparison with the control. The temporary increase of calcium level and decrease of inorganic phosphorus in these animals was accompanied by a lower activity of alkaline phosphatase. White and red grape press cake affected positively the vitamin E level in blood serum. In the muscles of the experimental slaughter pigs protein proportion was increased and fat proportion was decreased.     

Concentration of plasma testosterone in adult roosters of a low-weight strain

The levels of blood-plasma testosterone were studied in the adult light bodied strain cocks. Blood was sampled (1 ml) from the wing vein by means of a heparinized syringe six times within a 24-hour interval. The plasma obtained by centrifugation was kept in a refrigerator at a temperature of --18 degrees C. Testosterone was determined by the radioimmunological method. The testosterone levels were significantly higher (P less than 0.001), 18.8 nmol/l on the average, in the blood samples taken during the dark period of the day (10 o'clock p.m., 2 and 6 o'clock a.m.) than in the samples taken in the light part of the day (8 and 10 o'clock a.m., 2 o'clock p.m.) when the average concentration of the studied hormone was 10.7 nmol/l of plasma. the lowest levels of testosterone were recorded in the morning and the highest values were recorded late in the evening (10 o'clock p.m.). The differences in the levels of the hormone between sampling terms indicate that the testosterone level in adult animals shows diurnal variances. It was found by the study of the concentration of testosterone in the blood plasma of the same individuals within short intervals of time (30-60 min) that testosterone secretion in adult cocks had a pulsatory manner. The evaluation of hormone levels should include not only the diurnal variances but also the pulsatory manner of testosterone secretion.     

Campylobacter jejuni and its incidence in meat packaged under warm conditions

The problem of survival of Campylobacter jejuni was studied in artificially contaminated butchered meat packed in warm condition. Apart from the presence of Campylobacter jejuni, the total number of microorganisms and the shelf life of the meat were studied. With plain packing, Campylobacter jejuni survived six to seven days and the shelf life of the meat was about a week. In vacuum-packed meat Campylobacter jejuni was isolated for ten to eleven days and sensory changes occurred after ten to fourteen days. In meat packed in protective atmosphere Campylobacter jejuni was able to survive for ten to thirteen days and the meat kept its sensory properties for a fortnight or longer. There were no differences in the survival of Campylobacter jejuni in pork and beef, nor were there any substantial differences in the microorganism survival in PSE, DFD meat and in intact meat.     

Spectrophotometric method for differentiation of cardiac and hepatic lactate dehydrogenase activities in dogs

To differentiate the origin of high total lactate dehydrogenase (LD) activity in canine sera, a spectrophotometric method based on the preferential inhibition of cardiac LD isoenzymes by pyruvate was performed. Comparison with the electrophoretic separation of LD isoenzyme activities and determination of the hydroxybutyrate dehydrogenase-to-LD ratio indicated that the method proposed gave a better discrimination between cardiac and hepatic LD activities than did the other tests.     

The use of dried grape press cake in pig fattening]

In dried grape press cake the content of crude nutrients and ash, overall sugar, amino acids, alpha-tocopherol and gross energy was determined. In biological experiments with pigs (total of 109 animals) 10% of mixture A1 or SOL was replaced by the same amount of dried crushed grape press cake, without affecting negatively the weight gains and consumption of mixtures per unit of weight gain. Nutritional effects of grape press cake are a subject of discussion and comprise three factors: higher content of enrgy (fat and sugars) in mixtures containing press cake, anti-oxidation effect of press cake and the effect of tocopherols on the metabolism of basic nutrients.