Veterinarno-meditsinski nauki最新文献

Studied was the microbial decontamination of swine mature with the employment of a laboratory model of an aerobic lagoon as well as in a purification station, having a mechanical step, two biologic steps, and a facultative lagoon. It was found under modelled conditions that a substantial decontaminating effect was produced with regard to coli bacteria and Salmonella organisms. The effect was less with regard to the microbial count. The studies carried out in stations showed the effectiveness of the individual steps in reducing the microbial content of manure.

Studied were the etiology and spread of nonbacterial gastroenteritis in pigs over a period of five years. Ascertained were cases of diarrhea caused by the virus of transmissive gastroenteritis, epizootic diarrhea, and rotaviruses. The transmissive gastroenteritis virus was found in 14.1 per cent of the investigated material, mostly in the winter months (67.8 per cent), which was 65.6 per cent of the positive cases. The number of cases and that of the farms involved abruptly rose in the last two years of the investigated period when as many as 73.4 per cent of the positive findings were recorded. Thirty to 37.7 per cent of the studied farms proved to be infected. Enzootic diarrhea was recorded on seven out of the 12 studied farms, whereas 30 to 50 per cent of the sampled material was positive. The serologic study of reconvalescent blood sera of pigs from three infected farms revealed that 90 up to 100 per cent of them contained antibodies. In a great part of the sera (from 15 to 68.9 per cent) there were transmissive gastroenteritis antibodies as well. In 6.8 per cent of the Investigated samples and on 30 per cent of the farms there were also findings of rotaviruses. Cases of rotavirus gastroenteritis were recorded the year round with a rising trend in the cold months. Antibodies to these viruses were established on a large scale--from 58.13 to 100 per cent. There were also mixed infections--corona- and rotaviruses or viruses and bacteria.

Studied was the capacity of the soluble virus-specific glycoproteins of the virulent A-2 strain and its IUDR-resistant MK-25 mutant to induce the production of virus-neutralizing antibodies. It was found that both the purified virions and soluble glycoproteins of strain A-2 and those of strain MK-25 induced the release of virus-neutralizing antibodies in the injected rabbits. Use was made of affinity chromatography on Con-A-Sepharose to isolate the glycosylated virus-specific proteins. The quality of the soluble virus-specific glycoproteins to trigger the production of virus-neutralizing antibodies made it reasonable to believe that the virus glycoproteins are structural ones.

Studied was the immune response of calves, with colostrum antibodies and without colostrum antibodies, immunised with different dosages of live bivalent vaccine against P. parainfluenzae-3 and Adenovirus-1. For the group of calves with colostrum immunity, after single hypodermic immunisation with doses from 10(4) till 10(5) CPE50/cm3 for adenovirus, was not proved immune response, as a result of blocking of the vaccinal antigen of colostrum antibodies. For calves which missed these antibodies, the immune response was determined at the 15th day after the first vaccination with the lesser dose of bivaccine. Regardless of the degree of the antibodies of the calves, after the second vaccination (with the big and the little dose) was proved immune response, which does not differ considerably for the separated groups of calves. It was established, that the optimal dose, necessary for the calves to build an immunity at an early age (from 1 to 3 months), when immunised with bivaccine, was 10(4) CPE50/cm3 for the P. parainfluenzae-3 and 10(3) CPE50/cm3 for the Adenovirus-1. The bigger dose is useless not only from the economic point of view, but from the danger of provoking an unwanted shock of the vaccinated calves.

Complex morphologic, parasitologic, virologic, and bacteriologic studies on pigs and fecal samples from pigs were carried out on a farm where an enteritis infection in newborn pigs was recorded. A mixed coli-rotavirus and cryptosporidium infection was established in 10--20-day-old pigs of the Camborough hybrid with a clinically manifested enteritis syndrome. Morphologically, the cryptosporidium component of the infection substantiated atrophic and dystrophic changes in the intestinal epithelium. Developmental forms of the parasite were also found in the border wall of the enterocytes.

Radiotelemetric and biochemical investigations were carried out with a total of 40 freshly calved cows, divided into two groups in dependence on the form of the T wave of ECG. It was found that the biphase T wave spoke of the individual capacity of the body; it was retained only during the first months of the lactation period, and later on changed into a negative T wave. The configuration of the T wave was not essentially affected by the blood serum levels of total protein, blood sugar, LDH, AcAT, AlAT, Ca, P, and Mg. In the study of the alkaline-acid state dependable differences were established with the gas exchange of oxygen as measured by the indices pO2, SAT, and O2CT which were shown to be higher in cows with a biphase T wave. The registration of a positive branch of the biphase T wave was associated with the enhancement of excitation of the right chamber and the registration of its vector. In normal conditions the latter was not demonstrated by the dominating biopotentials of the left chamber.

The dynamics of cumulation was followed up of the products of peroxide oxidation of lipids (POL) during the storage of meat obtained from broiler birds, pigs, and calves, and the activity was determined of one of the systems responsible for the deposition of such products--the nonenzyme system. Results showed that the cumulation of POL products in sampled white poultry meat and meat of pigs and calves, stored for 20 days at -5 degrees to -10 degrees C had close values. The rate of deposition in red poultry meat appeared to be several times higher. Investigations into the activity of the nonenzyme system that produced catalytic effects with POL 4 to 5 hours after sampling the meat revealed that it was lowest in homogenates of calf meat, and it was highest in homogenates of poultry meat, especially of red poultry meat. In this respect the meat of pigs ranked second. The data of the two criteria used showed that the rate of POL in PSE meat was lower than in normal meat of pigs.

Investigations were carried out on the basic and mineral composition of the liver of slaughtered birds. It was found that the water content of the liver depended on the age and sex, with broilers it being 73.09 g%, with laying hens--72.56 g%, and with cocks--70.62 g%. Proteins had highest percent in the liver of cocks, followed by those in the liver of hens, geese, broilers, and turkeys. The content of fats was highest in the liver of turkey, and in a descending order followed geese, broilers, hens, and cocks. Mineral salts varied from 1.20 to 1.35 g%; highest amounts of sodium were found in the liver of broilers, while highest levels of potassium, calcium, phosphorus, iron, zinc, and copper were established in the liver of turkeys.

Histologic and electron-microscopic studies were carried out on pale-soft-exudative (PSE) and pale-soft (PS) swine meat taken from musculus longissimus thoracis et lumborum. PSE meat was shown to have more strongly manifested morphologic changes. Histologically, with some of the samples there were 'gigantic fibers', their dia exceeding several tens of times the dia of fibers taken from control animals. The electron microscopy with some of the samples revealed a strong deformation of the myofibrils (extensions alternating with narrowings), broader Z-bands, loss of striation in the anisotropic zones, confluence of myofibrils in individual portions, granular destruction or fragmentation of sarcoplasm with swollen or disrupted mitochondria in it, strongly disrupted or destructed Z-bands, lysed or hyperchromic nuclei of the fibers, etc. In PS meat the same ultrastructural changes were observed, although they were less strongly manifested. With such meat some of the samples showed total destruction of the Z-bands, which had led to the full separation of sarcomeres (a phenomenon observed for the first time). These results constitute a contribution to the knowledge of the mechanism through which the PSE meat phenomenon occurs and the evaluation of such meat for consumption.