Aflatoxicosis in rabbits: Effectiveness of Egyptian raw bentonite in prevention or diminution the detrimental effects of naturally aflatoxin contaminated diets

Thirty five females and 15 males of New Zealand White mature rabbits about 6 months of age, were assigned to 1–5 dietary treatments (7 does+3 bucks for each): uncontaminated control diet, naturally aflatoxin contaminated diet without or with 1,2 and 3% bentonite. Rabbit fed with the aflatoxin-diet had a decreased (P<0.01 or 0.05) physical semen characteristics of bucks and a reproductive performance traits of does. The values of conception rate (%), gestation length (days), litter size (n) and litter weights (g) at birth and viability (%) of litters of doe rabbits, fed with the aflatoxin-diet, recorded, respectively: 64.5; 31.0; 4.4; 275.0 and 57.1 versus 85.6; 30.3; 7.9; 508.0; and 100 for those fed with the uncontaminated diet. Addition of bentonite to the aflatoxin contaminated diet improved in general the physical semen characteristics of buck and reproductive performance traits of doe rabbits. The results of the study demonstrate that adding 1% of Egyptian raw bentonite to the naturally aflatoxin contaminated rabbit diets can provide an effective, cheap and safe practical technique for preventing the aflatoxicosis in mature rabbits.     

Interaction of chemical and state effects on ventilation during sleep onset

Dunai, Judith, Mal Wilkinson, and John Trinder.Interaction of chemical and state effects on ventilation duringsleep onset. J. Appl. Physiol. 81(5):2235-2243, 1996.Ventilation varies as a function of state, beinghigher during wakefulness (as indicated by alpha electroencephalogramactivity) than during sleep (theta activity). A recent experimentobserved a progressive increase in the magnitude of these state-relatedfluctuations in ventilation over the sleep-onset period (28). The aimof the present experiment was to test the hypothesis that this effectresulted from chemical (feedback-related) amplification of stateeffects on ventilation. A hyperoxic condition was used to eliminateperipheral chemoreceptor activity. It was hypothesized that hyperoxiawould reduce the amplification of changes in ventilation associatedwith electroencephalogram state transitions. Ventilation was measuredover the sleep-onset period under both hyperoxic and normoxicconditions in 10 young healthy male subjects. Sleep onsets were dividedinto three phases. Phase 1 corresponded to presleep wakefulness; andphases 2 and 3 corresponded to early and late sleep onset,respectively. The magnitudes of state-related changes in ventilationduring phases 2 and 3, and under hyperoxic and normoxic conditions werecompared using a phase by condition analysis of variance. Resultsrevealed a significant phase by condition interaction, confirming that hyperoxia reduced the amplification of state-related changes in ventilation by selectively decreasing the magnitude of phase 3 statechanges in ventilation. However, some degree of amplification wasevident during hyperoxia, thus the results demonstrated that peripheralchemoreceptor activity contributed to the amplification ofstate-related changes in ventilation but that additional factors mayalso be involved.

     

Moderate exercise and bright light treatment in overweight and obese individuals

Objective: Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals. Research Methods and Procedures: Twenty‐five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep. Results: Body weight decreased significantly with exercise in subjects in the light and non‐light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep. Discussion: This preliminary study is the first to show that addition of bright light treatment to a 6‐week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.     

Ventilatory instability during sleep onset in individuals with high peripheral chemosensitivity.

Previous work has shown that the magnitude of state-related ventilatory fluctuations is amplified over the sleep-onset period and that this amplification is partly due to peripheral chemoreceptor activity, because it is reduced by hyperoxia (J. Dunai, M. Wilkinson, and J. Trinder. J. Appl. Physiol. 81: 2235-2243, 1996). These data also indicated considerable intersubject variability in the magnitude of amplification. A possible source of this variability is individual differences in peripheral chemoreceptor drive (PCD). We tested this hypothesis by measuring state-related ventilatory fluctuations throughout sleep onset under normoxic and hyperoxic conditions in subjects with high and low PCD. Results demonstrated that high-PCD subjects experienced significantly greater amplification of state-related ventilatory fluctuations than did low-PCD subjects. In addition, hyperoxia significantly reduced the amplification effect in high-PCD subjects but had little effect in low-PCD subjects. These results indicate that individuals with high PCD are likely to experience greater sleep-related ventilatory instability and suggest that peripheral chemoreceptor activity can contribute to sleep-disordered breathing.