Serum antibody response and Cryptosporidium parvum oocyst antigens recognized by sera from naturally infected sheep.

The response of specific serum immunoglobulins (IgG, IgM and IgA) and the major antigens of Cryptosporidium parvum recognized by these isotypes were investigated by using enzyme-linked immunosorbent assay and immunoblot techniques in lambs and ewes naturally infected throughout an outbreak of cryptosporidiosis. Serum samples were collected from 20 lambs the first day they showed diarrhoea (D1), and Days 11 and 22, in addition to single serum samples from 17 of their dams. Serum anti-C. parvum IgG, IgM and/or IgA antibodies were detected in lambs as early as Day 1. Levels of IgM antibodies remained steady from D1 to D11 and increased at D22, whereas the IgG response decreased from D1 to D11 and subsequently increased. In contrast, IgA antibodies rapidly fell from D1 and all lambs were seronegative at D11 and D22. The highest levels of specific antibodies were detected in sera from ewes. In fact, all ewes were seropositives for IgM and IgA isotypes and most (16/17) showed positive levels of IgG. Four protein fractions (37-39, 42-48, 51-57 and 60-69 kDa) were the most frequently recognized by IgG and IgM from lamb sera. A low molecular weight fraction (12-14 kDa) reacting with IgG and IgA in most lamb sera was scarcely recognized by IgM and three broad bands were frequently recognized by IgA antibodies (23-25, 51-57 and 90-95 kDa). The recognition pattern of 23-25 kDa peptides by IgA from lamb sera clearly increased with the age. Peptides of 42-48, 51-57, 60-69 and 71-78 kDa were most frequently recognized by IgG and IgM from ewe sera. In relation to IgA antibodies from ewe sera, a frequent immunoreactivity was found with proteins in the intervals between 12 and 22 kDa as well as between 32 and 34 kDa and practically all sera reacted with fractions from 42 to 95 kDa.     

Pharmacokinetics of pipemidic acid in chickens after single intravenous and oral dosings

The pharmacokinetics of pipemidic acid after 2 single doses were studied in broiler chickens. Chickens were given single IV and oral doses of 10 and 30 mg of pipemidic acid/kg of body weight. Blood samples were collected over 8 hours after each dose administration. High-pressure liquid chromatography with UV detection was used to determine concentrations in plasma of pipemidic acid. The plasma concentration-time curves after IV administration followed 2-compartment characteristics, rapid initial distribution phase, and a terminal elimination phase. The pharmacokinetic variables differed significantly between single doses of 10 and 30 mg of pipemidic acid/kg. Mean disposition variables were a half-life at alpha phase of 0.06 hours or 0.33 hours, a half-life at beta phase of 1.18 hours or 1.72 hours, a volume of distribution in the central compartment of 0.12 L/kg or 0.31 L/kg, a volume of distribution during the elimination beta phase of 1.64 L/kg or 1.05 L/kg, and a total plasma clearance of 0.97 L/h.kg or 0.41 L/h.kg, for the 10 or 30 mg/kg dose, respectively. After oral administration, the pipemidic acid plasma profile could be adequately described by a 1-compartment model. After the single oral doses of 10 and 30 mg of pipemidic acid/kg, pipemidic acid was absorbed rapidly (time to maximal concentration of 0.31 hours or 0.71 hours) and eliminated with a mean half-life of 0.86 hours or 0.61 hours, respectively. The bioavailability was 39% at 10 mg of pipemidic acid/kg and 61% at 30 mg of pipemidic acid/kg.     

The susceptibility of Lymnaeid snails to Paramphistomum cervi infections in Mexico

The occurrence of Paramphistomum cervi has been reported in Mexico, but its intermediate hosts have not been identified. Five species of snails of the genus Lymnaea, L. bulimoides, L. columella, L. cubensis, L. humilis and L. palustris, were collected in Mexico. Only three of the exposed species, L. palustris, L. cubensis and L. humilis, became infected with P. cervi. The first of these snail species was highly susceptible to infection and a higher number of the exposed snails shed cercariae. It is suggested that L, palustris may act as an important vector of P. cervi in Mexico.     

The effect of ionizing radiation on structural changes in the energy nutrients in animal feed

For the purpose of testing the effect of ionizing radiation, feeds for dogs (meat feed mixture VETACAN and loose feed mixture VETAVIT) irradiated by 60Co radioisotope at the dose of 25 kGy/kg were studied for 60 days. It has been found out that the total volume of energetic and non-energetic nutrients is not changed. Qualitative structure, however, displays a significant, on the average 35% disintegration of essential amino acids, decrease of proteins and increase of free ammonic bases. A significant oxidation effect of radiation is exerted on the decomposition of fats with a release of free fatty acids from glycerol bond in a process similar to rancidification (from 13.3-37.10 mg/g in meat mixture, from 103.1-103.04-135.04 mg/g in loose mixture). A certain disintegration of nutrients, only within the limits of significance, occurred also in the saccharide proportion of the loose feed mixture (acidity of water extract 348.8-403.99-436.60 mg/100 g). It has been proved that radiosterilization reliably secures microbiological and mycological sanitation of feeds and causes no sensory changes noticeable by human senses. It follows from the results that ionizing radiation has a pronounced antimicrobial and antimycotic effectiveness. However, it causes significant structural changes of energetic nutrients in the feeds of animal as well as of vegetable origin.     

The effect of feeds treated with ionizing irradiation on biochemical indicators of the nutritional value of energy nutrients

The influence of feedstuffs treated with ionizing radiation on the nutrition of dogs was tested in four groups of animals. Two groups were administered for 90 days a ration, the main part of which (VETACAN meat feed mixture and VETAVIT loose feed mixture) was irradiated with radioisotope Co 60 of the intensity of 25 kGy/kg, in other two groups of dogs the nonirradiated ration was used for the same time period. The control groups of dogs were put together for these two diets. The laboratory examination of irradiated feedstuffs confirmed their complete microbiological and mycological intactness. However, the irradiation brought about a significant 35% degradation of essential amino acids with an increase of ammonia nitrogen, destructive changes in the lipid component of feedstuffs and a partial decomposition of the saccharide part of the VETAVIT feed mixture, expressed by the acidity of water extract. The sensory evaluation of irradiated feedstuffs did not show any perceptible alterations. The haematological examination of the blood of animals, which had been administered irradiated feed rations, demonstrated a significant negative influence on the blood picture. The biochemical examination of the blood serum and plasma revealed that total proteins of experimental dogs dropped and the creatinine level was also significantly decreased. Neither was the level of carbohydrate nutrition nor the energy saturation affected by irradiation. The glucose levels in the blood serum of dogs fluctuated within the range of physiological reference values. The growth of free ammoniacal bases of feedstuffs, evoked by ionizing radiation, conditioned obviously the level of actual pH of blood in dogs as determined in this study. The destruction of lipoid fraction in the feedstuffs induced a decrease in the activity of lipophile retinol and thus the biological value of feeds was impaired. The biochemical examination of ALT, AST and ALP enzyme activity did not show any increased activity of parenchyma, in particular of liver cell. A decisive role of the biological quality of feed ration for utilization of some minerals was demonstrated by a significant decrease of the magnesium level in animals administered irradiated feed rations without any biological supplementation. On the contrary, the potassium, calcium and phosphorus levels did not reflect this dietary difference between the groups.     

Morphologic changes in the ovary and histologic changes in the tertiary ovarian follicles in ewes after prolonged irradiation during anestrus

The changes in volume, weight and the histomorphological changes of the tertiary follicles of ewes were studied after protracted irradiation with 4.8 Gy in the anoestrous period by the morphometric and qualitative histological methods. The trial was performed in May with 21 ewes of the Slovak Merino breed, divided into three groups. The first group (five ewes) was control. The second and third groups (each containing eight ewes) were exposed to gamma-rays for five days, the total dose being 4.8 Gy. Within ten days after the treatment, all the irradiated and control ewes were given Ampicillin Spofa per os at a dose of 250 mg per head/day and Roboran Spofa at a dose of 10 g per head/day. The animals were killed by bleeding on the fifth day of irradiation and on the tenth day after the end of the treatment. After killing, the volume and weight of the ovaries were determined and a common histological method was used to cut these ovaries into 7 microns slices in series 70 microns apart. The slices were stained with haematoxylin-eosine and were evaluated by means of light microscopy. After irradiation the weight of the ovaries was found to decrease significantly; however, ovary volume remained unchanged. The atretic and non-atretic tertiary follicles were subjected to qualitative histological differentiation after Marion et al. (1968) and the number of non-atretic follicles was found to have decreased significantly in the irradiated ewes. The late type of atresia contributes most significantly to an increase in the proportion of atretic tertiary follicles. The administration of vitamins after irradiation reduced the occurrence of atretic changes.     

Detection of staphylococcal enterotoxins in milk and milk products

For food evaluation the determination of the number of Staphylococcus aureus (hereinafter S. aureus) colonies is insufficient in view of present scientific knowledge. The results, advantages and shortcomings of diagnostic methods are demonstrated on an example of three methods of detection of staphylococcal enterotoxins in milk and milk products. 133 strains were investigated by the method of biotyping of S. aureus strains. Four strains of S. aureus were included in biotype A, seven xin-producing strains were isolated seventeen times by detection of 96 S. aureus strains were not included in any biotype, the other strains belonged to biotypes C and E. This method can be used as an auxiliary method of evaluation of foods containing S. aureus bacteria. The agar-gel precipitation method of enterotoxin detection in isolated strains of S. aureus has just restricted validity. The enteroto-strains. The main shortcoming of this method is a fact that the result concerning the isolated strains need not be identical with the result of enterotoxin detection in food. Direct assays of staphylococcal enterotoxins in milk and milk products using an enzymoimmunological method seem to be the most promising, mainly due to their high sensitivity (0.0001-0.001 micrograms.ml1-) and other advantages. Positive and negative results are presented on an example of two model trials with winter sheep milk cheese.