Infleuce of dietary levels of vitamin E and selenium on tissue and blood parameters in pigs.

Eighteen barrows approximately three weeks of age were used in a 3 X 3 factorial arrangement to investigate the effect of level of supplemental vitamin E and selenium on tissue and blood parameters. Tissue selenium concentrations increased in a quadratic manner with increased selenium intake with kidney tissue containing considerably greater concentrations than liver, heart or muscle. Supplementation of the diet caused a three-fold increase in serum selenium within the first week with a slight tendency to further increases in subsequent weeks. Serum vitamin E of unsupplemented pigs declined by fifty percent during the experiment, whereas supplemental vitamin E resulted in increased serum vitamin E. There was a considerable viration in percent peroxide hemolysis. Correlation of -0.63 between percent peroxide hemolysis and vitamin E intake and -0.85 between percent peroxide hemolysis and serum vitamin E were observed.     

Flow cytometric assessment of ethylene glycol monoethyl ether on spermatogenesis in rats

The effects of ethylene glycol monoethyl ether (EGEE) on testicular cell populations in rats were investigated by a flow cytometric method. Rats were administered by gavage with EGEE at the various doses of 0 (saline alone), 100, 200, 400, and 800 mg/kg body weight/day for 4 weeks. The treatment of EGEE caused decreases in the weight of testis and epididymis and in the number of testicular cells. Histopathologically, exfoliation of germ cells into the tubular lumen was observed at the doses of above 200 mg/kg. The treatment of EGEE at the dose of 400 mg/kg caused moderate testicular degeneration. A significant depletion of haploid cells and a disproportionate ratio of diploid and tetraploid cells were observed as determined by flow cytometric analysis. These results indicate that the toxic effect of EGEE on the male reproductive system may be strongly associated with the disproportion of testicular germ cells.     

Does the Presence of Detached Root Border Cells of Zea mays Alter the Activity of the Pathogenic Nematode Meloidogyne incognita?

ABSTRACT The root-knot nematode Meloidogyne incognita is a major pathogen of a range of important crops. Currently, control is typically achieved by the use of nematicides. However, recent work suggests that manipulating the ability of roots to slough off border cells, which then act as a decoy to the nematode, can significantly decrease damage to the roots. We investigated the attractiveness of border cells to M. incognita and the response of the nematode to border cells in close proximity. We found very limited attraction, in that nematodes did not preferentially alter direction to move toward the border cells, but a large and significant increase in nematode speed was observed once they were in the immediate vicinity of border cells. We discuss the results in the context of physical and biological mechanisms in relation to the control of pathogenic nematodes.     

Comparison of the cardiopulmonary effects of anesthesia maintained by continuous infusion of romifidine,guaifenesin, and ketamine with anesthesia maintained by inhalation of halothane in horses

OBJECTIVE: To compare cardiopulmonary responses during anesthesia maintained with halothane and responses during anesthesia maintained by use of a total intravenous anesthetic (TIVA) regimen in horses. ANIMALS: 7 healthy adult horses (1 female, 6 geldings). PROCEDURE: Each horse was anesthetized twice. Romifidine was administered IV, and anesthesia was induced by IV administration of ketamine. Anesthesia was maintained for 75 minutes by administration of halothane (HA) or IV infusion of romifidine, guaifenesin, and ketamine (TIVA). The order for TIVA or HA was randomized. Cardiopulmonary variables were measured 40, 60, and 75 minutes after the start of HA orTIVA. RESULTS: Systolic, diastolic, and mean carotid arterial pressures, velocity time integral, and peak acceleration of aortic blood flow were greater, and systolic, diastolic, and mean pulmonary arterial pressure were lower at all time points for TIVA than for HA. Pre-ejection period was shorter and ejection time was longer for TIVA than for HA. Heart rate was greater for HA at 60 minutes. Minute ventilation and alveolar ventilation were greater and inspiratory time was longer for TIVA than for HA at 75 minutes. The PaCO2 was higher at 60 and 75 minutes for HA than forTIVA. CONCLUSIONS AND CLINICAL RELEVANCE: Horses receiving a constant-rate infusion of romifidine, guaifenesin, and ketamine maintained higher arterial blood pressures than when they were administered HA. There was some indication that left ventricular function may be better during TIVA, but influences of preload and afterload on measured variables could account for some of these differences.     

Can goats learn about foods through conditioned food aversions and preferences when multiple food options are simultaneously available?

The objective of this study was to determine the extent to which herbivores are able to use conditioned food aversions and preferences to learn about the nutritional and toxic properties of food plants, when food options are simultaneously available. Conditioned food aversions and preferences have been invoked as important mechanisms by which free-ranging herbivores optimize food selection by learning about the negative and positive consequences of consuming particular plant species through a series of encounters. In most previous tests of this hypothesis, access to individual test foods has been separated in time, giving animals the opportunity to associate particular foods with particular post-ingestive effects. We presented animals with a more complex scenario by offering test feeds simultaneously during the learning phase. Such a test is an important step in assessing the importance of conditioned food responses as mechanisms by which herbivores learn to select an optimal diet. We first assessed the ability of goats to learn about test foods and their post-ingestive effects, when different conifer species were offered on separate days during the learning phase and animals were dosed with compounds eliciting positive, negative, or neutral post-ingestive effects. We then investigated the ability of animals to learn to make appropriate choices when all potential test foods were simultaneously available during the learning phase. The results confirmed that goats can learn to associate particular foods with particular post-ingestive effects and adjust their diet selection accordingly. The success with which animals made such associations was greatly reduced when they were presented with test foods simultaneously during the learning phase. When test foods were simultaneously available, animals tended to select a mixed diet, thereby reducing their opportunity to learn about the post-ingestive effects of particular foods. The results suggest that caution is required in extrapolating results of artificial conditioning experiments to free-ranging herbivores. The results also suggest that reducing the risk of toxicity through selection of mixed diets is an important component of a successful foraging strategy.