Vitamin C supplementation has no effect on American bullfrog's immune response.

American bullfrog (Lithobates catesbeianus) is the only species raised in Brazilian commercial frog farms, and the intensive culture of these animals has gained great popularity in Brazil over the past several years. Stress is one of the major obstacles in frog culture. To minimise this problem, the aim of the present study was to investigate the role of added vitamin C in the diet of American bullfrogs as an antistress factor through the assessment of plasma corticosterone, leucocyte levels and macrophage activation in animals raised in confinement. The experimental design was entirely randomised, with six treatments (supplementation of 0, 250, 500, 750, 1000 and 2000 mg of vitamin C/kg of feed) and four replications. The plasma corticosterone level, leucocyte level and macrophage activation were evaluated. It was concluded that vitamin C had no influence on the evaluated parameters due to the possible adaptation of the animals to life in captivity (domestication). The results of this research indicate that farmers should not increase the levels of vitamin C in commercial feeds because this would only enhance production costs.

Evaluation of a dosing method for studying ergonovine effects in cattle.

We evaluated the feasibility of using miniosmotic pumps as a way to continuously treat cattle with a singular ergot alkaloid (ergonovine) of known content, thus mimicking the natural fescue toxicosis disease state, but allowing study of specific alkaloid effects. Dosing animals with increasing amounts of ergonovine via miniosomotic pumps, followed by daily acquisition of plasma samples for high-performance liquid chromatographic determination of the alkaloid, resulted in stepwise increases in plasma ergonovine concentration. However, despite the detectable blood concentration of ergonovine, calves did not have typical clinical signs of ergot alkaloid toxicosis. Similarly, serum prolactin concentration was unaffected by ergonovine in these cattle, implicating some other alkaloid of endophyte-infested fescue as causative of the usual prolactin-suppressive response. The results confirm use of this animal dosing method to study biological effects of singular purified alkaloids of known amount, without bioavailability concerns. Thus, this dosing method will facilitate studies to determine the harmful effects of individual alkaloids found in toxic tall fescue, and ultimately, to alleviate their costly effects in cattle, horses, and other species.

Relieving stress through value-rich work.

On the basis of Herzberg, Mausner, and Snyderman's (1959) motivator-hygiene theory, it was hypothesized that intrinsic but not extrinsic work values would be inversely related to stress. Also investigated was the question of which work values provide the most relief from stress. Elementary school teachers and administrators (N = 607) from nine school boards in southern Ontario completed a survey that included Pines, Aronson, and Kafry's (1981) stress scale and Elizur's (1984) work values scale. Almost all of the 12 intrinsic work values investigated were negatively correlated with stress, but the 4 extrinsic work values studied were not consistently related to stress. Five work values explained 11% of the variance in physical stress, 9 work values explained 22% of the variance in emotional stress, and 6 work values explained 26% of the variance in mental stress. Four work values emerged as meaningful predictors of all three types of stress: being esteemed by others, achieving through work, doing meaningful work, and being able to use one's knowledge and abilities.

Locus of control: a work-related variable?

Inconsistencies in findings between age and perceived locus of control of reinforcement were examined in light of social learning theory. Absence of work was hypothesized to reduce opportunities for reinforcement and thus expectancies. No differences were found in internal-external (I-E) locus of control among nine age groups (20 to 65 years) for subjects (882 school teachers) during the span of their work lives. It seems that I-E depends on the frequency and intensity of expectancies for behavior reinforcement sequences that work affords. Before and after work life there is not only less to control, but many of the nonwork reinforcers are not contingent on one's own behavior. Relinquishing internal control and a shift of focus toward reflection on experience and meaning of ife may well be a desirable and natural process for older people.

Relationships among job involvement, job satisfaction, and organizational commitment for nurses.

The relationships among a cluster of attitudes toward work and job were investigated using a sample of 171 nurses. The hypothesis was that involvement in work and job, commitment to the employing organization, and satisfaction with the job (overall, and with specific facets of the job) would be significantly correlated. The results showed that involvement was not related to overall satisfaction but only to two specific facets, satisfaction with work and promotion opportunities. In contrast, the degree of relationship between overall and various facets of satisfaction and commitment and between involvement and commitment was moderately high.