[Histologic and histomorphometric changes of testis following oral exposure to methyl tertiary-butyl ether in adult rat]

Methyl tertiary-butyl ether [MTBE] is used to reduce carbon monoxide and ozone in urban air and to boost fuel octane. There is a lack of knowledge in the literature about the histomorphometric changes of the testis following exposure to MTBE. Therefore, this experimental study was performed to determine the effect of oral exposure to MTBE on histologic and histomorphometric changes of testis in adult rat. A total of 25 adult male Sprague-Dawley rats were randomly divided into five equal experimental groups: control, almond oil and three treatment groups which received 400, 800 and 1600 mg/kg/day MTBE in almond oil by gavages for 30 consecutive days. Histomorphometric analysis showed no significant difference in absolute and relative testis weight, connective tissue thickness, germinal epithelium height, tunica albuginea thickness and Sertoli cell numbers between experimental groups [P>0.05]. However, trend analysis showed that the seminiferous tubule diameter increased and interstitial cell numbers as well as spermatocyte and spermatid cell numbers decreased significantly in MTBE treated groups [P<0.05]. It may be concluded that MTBE could exert adverse effects on spermatogenic cells in adult rat. Whether the observed changes in the present study are due to the direct effect of MTBE via passing blood-testis barrier or its indirect effect through another mechanism should be elucidated in future studies.

Relationship between venous blood gas parameters, thyroid hormone levels and ascites syndrome in broiler chickens exposed to cold temperature

The objective of this study was to find a relationship between blood gas parameters and thyroid hormone activity with ascites syndrome in broiler chickens exposed to cold temperature and receiving a high quality diet. One hundred and sixty one-day-old broiler chicks were randomly divided in two equal groups. To increase the incidence of ascites, chicks of group 1 were fed ad libitum with a higher condensed diet and reared under a lower ambient temperature. Weekly, blood gas parameters and thyroid hormone levels were measured and growth performance was recorded. The hearts of dead and slaughtered birds were examined for determination of arterial pressure index [API] values. Ascites incidence was clearly higher in cold-exposing chickens compared with normal rearing chickens. The mean values of carbon dioxide tension of group 1 chickens were significantly higher compared with group 2 chickens at the 4th and 5th weeks of age, while the phenomenon of oxygen was reversed in these two experimental groups. The function of thyroid hormone levels were changed at week 4 of age, as observed for blood gas parameters. In conclusion, the present study showed a significant association between thyroid hormones functions, the levels of venous blood carbon dioxide and oxygen pressures in the two groups of chickens

Lethal effect of high temperatures on the eggs of fasciola hepatica

Fasciolosis is a cosmopolitan parasitic disease with considerable economic and public health importance. Fasciola hepatica is the major cause of fasciolosis in man and domestic animals. Although remarkable research works have been done around the optimum temperature and time required for miracidial development, little is known about the exact susceptibility of Fasciola hepatica eggs to high temperatures. In the present study, Fasciola hepatica eggs were initially incubated at 40°C, 45°C, and 50°C for various times [1, 2, 3, 4 and 5 h], followed by incubation at 28°C for 16 days. Miracidial formation was subsequently investigated on the 16th day of incubation. Even though the rate of miracidial formation in the control group was 52%, in the eggs incubated at 40°C for 1, 3, and 5 h, the miracidial formations were 51.4%, 42.4% and 39.9%, respectively, and these values in the group incubated at 45°C were 46%, 42.5% and 33.7%, as well. However, in the case of incubation at 50°C for 1, 2, 3, 4 and 5 h, these values were recorded as 1.96%, 0.57%, 0.07%, 0.00% and 0.00%, respectively. The results indicated that the eggs were susceptible to high temperatures and incubation of the eggs at 50°C for 4 h was enough to significantly inactivate the eggs and prevent miracidial formation [P<0.001]. However, using the livestock faeces as fertilizer in many rural areas may lead to the contamination of pasture. According to the findings of this study, in the areas with a high prevalence rate of Fasciola hepatica, manure storage for a sufficient time or heating the livestock manure before use as fertilizer is strongly recommended

Study on the frequency of cardiac dysrhythmias in apparently healthy horses of riding schools [Shiraz, Isfehan, and Tehran]

To find the frequency of cardiac dysrhythmiasin apparently healthy horses and discriminate functionalfrom pathological ones. Observational field study. The study was conducted on 544 horses but ECGwas recorded only from 395 cases. Data were evaluated by using analysisvariance and Chi-square. ECG was obtained on a base apex lead withthe paper speed of 25mm/sec and calibration of l0mm/mVat rest without restraining or using of tranquilizers. Thefindings were evaluated according to the criteria of normalcardiac rhythm. 102 out of 395 horses used for ECG recording hadsome types of cardiac arrhythmias [25.82%]. The mostfrequent dysrhythmias were heart block, sinus arrhythmiaand sinus tachycardia, respectively. Atrial fibrillation wasnot seen. This study showed that horses of ridingschools show cardiac dysrhythmias just like race horses.Major cardiac dysrhythmias are functional ones. Atrial andventricular premature beats should be cautiously looked.Furthermore, in contrast to what has been reported in theveterinary literature, no case of atrial fibrillation was seen.This dysrhythmia seems to be very rare among Iranianequine population for some unknown reasons