Modulation of the HPA axis alters the sensitivity of the cochlea to acoustic trauma

The hypothalamic pituitary adrenal axis (HPA axis) regulates nearly all neuroendocrine responses of the body. An active HPA axis is crucial to maintaining homeostasis. An altered reactivity of the HPA axis can affect several physiological systems including the auditory system. The mechanism underlying the interaction between the HPA axis and the auditory system is not known. The overall objective of this thesis was to define the functional relationship between the HPA axis and the auditory system and to evaluate the underlying mechanisms. The results presented in this thesis demonstrate how the cochlea is protected against acoustic trauma with previous activation of HPA axis. Activation of the HPA axis with either restraint stress or sound conditioning prior to acoustic trauma significantly elevates plasma corticosterone, activates GRs in the paraventricular nucleus (PVN), spiral ganglion neurons (SGN) and significantly lowers ABR threshold shifts. This protective effect was block by either adrenalectomy or combine use of glueocorticoid synthesis inhibitor (metyrapone) or receptor antagonist (RU486). Moreover, the combined use of metyrapone and RU486 prior to acoustic trauma leads to the exacerbation of hearing loss indicating that an optimal HPA axis response is crucial for the recovery from trauma. Nuclear factor kappa B (NFêB), a GR regulated transcription factor, was also involved in this corticosterone mediated protective mechanism. Enhancement of nuclear translocation of NFê13 in the spiral ganglion neurons coincides with lower ABR threshold shifts indicating an interaction between GR and NFê13 in the SGNs. This can be the main factor, which contributes to the protection of cochlea against acoustic trauma. A selective NFêB inhibitor PDTC was use to confirm the role of NFêB in the cochlea. Pretreatment of PDTC caused an elevation of auditory thresholds and lowered nuclear translocation of NFêB in the SGNs. Steroid receptor co activator 1 (SRC-1), a GR co- regulatory protein also contributes to this GR mediated protective mechanism of hearing. The expression of SRC1 in the SGN was increase after sound conditioning and acoustic trauma, which could be the probable mechanism of sound conditioning triggered protection of hearing. In conclusion, the findings from this study imply that the HPA axis modulates the sensitivity of the cochlea against acoustic trauma by the release of glucocorticoid. Glueocorticoid regulates the expression and activation of GR locally in the cochlea. Active GR interacts with transcription factor NFêB and this interaction ultimately determines the susceptibility of cochlea against acoustic trauma

Dietary Effects of Garlic (Allium sativum) Powder on Growth Performance of Commercial Broiler

The study was conducted during summer (April-May) to investigate the growth performance of 120-day-old mixed-sex commercial broiler chicks (Cobb-400) by examining the dietary effects of different levels of garlic (Allium sativum) powder supplementation. In a 28-day experiment, four distinct diets (T1, T2, T3, and T4) were utilized, each containing varying amounts of dried garlic powder (0%, 0.5%, 1%, and 2%). The effectiveness of garlic powder on feeding was evaluated by measuring weight gain, feed consumption, feed efficiency, dressing yield, and survivability. The results showed that there were no significant differences in body weight gain among the treatment groups in the first seven days. However, significant differences were observed in broiler diets containing 0.5%, 1%, and 2% garlic powder during the 8-14, 15-21, and 22-28 day periods, with the highest body weight gain observed in birds fed a diet containing 1% garlic powder. Furthermore, significant enhancements (P<0.05) in the feed conversion ratio (FCR) were observed by increasing the inclusion of garlic powder compared to the control group during specific age periods (1-7, 15-21, and 22-28 days), with the treatment group fed with 1% garlic powder exhibiting the most favorable FCR at the trial’s conclusion. Regarding feed intake and survivability, the study showed no significant differences (P>0.05) in broilers with different dietary treatments. The inclusion of garlic powder in broiler feed led to a notable decrease in fat content and an increase in dressing yield, with the highest yield achieved at a 1% supplementation level. Therefore, the study suggests that 1% garlic powder could be a potential feed additive to enhance the overall performance of the broiler

Knowledge and Attitude towards COVID-19: A Cross Sectional Study in Bangladesh through Phone and Online Survey

Aim: This study investigated the knowledge and attitudes towards COVID-19 in Bangladeshi adults by online and phone survey methods during the early stage of its spread. Methods: Data were collected through phone calls (April 14-23, 2020) and online survey (April 18-19, 2020) in Bangladesh. The questionnaire had 20 knowledge questions with each correct response getting one point and incorrect/don’t know response getting no point (maximum total knowledge score 20). Participants scoring >17 were categorized as having good knowledge. Results: The percentages of good knowledge holders were 57.6%, 75.1%, and 95.8% in the phone, online non-medical, and online medical participants, respectively. Most of the phone and online participants had good knowledge of the preventive practices of COVID-19. However, among the non-medical participants (both phone and online), the correct response rates were lower than 80% for the knowledge questions asking about the facts that - some patients may have no symptoms, diarrhea is a symptom of this disease and that it cannot be prevented by any currently available medication. Male gender, higher education, living in town/urban areas, good financial condition, and use of internet were positively associated with higher knowledge score among the non-medical participants. However, higher knowledge score was associated with having less confidence in the final control of COVID-19. Conclusion: Our study identified some COVID-19 information that were less known among the participants and the potential factors that were associated with having good versus poor knowledge. Besides, this study sheds light on the attitude of Bangladeshi adults towards COVID-19