Research Publications

The present work was carried out to calculate the half lethal concentrations (LC50) of three inorganic fertilizers (balanced, high phosphorus and high nitrogen fertilizers) on Biomphalaria alexandrina snails and to demonstrate measurable effects on infected B. alexandrina with Schistosoma mansoni miracidia that were exposed for one week to 1/4 LC50 (126.4, 400 and 2375 ppm) separately of (balanced, high phosphorus and high nitrogen) fertilizers, respectively. The obtained results showed that the survival of all treated infected snail groups at the 1st shedding were significantly less than the control group. Moreover, results revealed a marked reduction in the infectivity of the infected snails especially those exposed to sublethal concentration of high nitrogen fertilizer when compared to control. In addition, the cercarial production of all treated groups was completely suppressed. These infected snails exhibited histopathological alterations, which is associated with severe damage in the digestive gland cells as well as the mother sporocysts of treated infected snails. Our study revealed the biological and histopathological effects of three inorganic fertilizers on infected Biomphalaria alexandrina snails.

The present study deal with three inorganic fertilizers they were; (balanced, high phosphorus and high nitrogen), their (LC50) values were 505.7, 1600 and 9500 ppm, respectively after 24 hours of exposure. Survival rate of B. alexandrina snails group that exposed to sublethal concentrations of balanced fertilizer showed a gradual reduction, that increase with increasing the used concentrations. On the other hand, the application of both high phosphorus and high nitrogen fertilizers had more powerful effect on the treated snails and the declining of survivorship and egg laying capacity was inversely proportional to the concentrations. In addition, SDS–PAGE protein profiles of treated snails revealed that the minimum number of protein bands was noticed in tissue and hemolymph of snails groups that subjected to high phosphorus and high nitrogen fertilizers compared to control protein fractions. The highest similarity indices values (0.50 and 0.42) were obtained when snails exposed to ¼ LC50 and ½ LC50 doses of balanced fertilizers in tissue and hemolymph, respectively after four week. © 2015 AENSI Publisher All rights reserved.

In this study, the most effective agent was Difenoconazole (Score) followed by Asparagus densiflours then Oreopanax guatemalensis plants against Biomphalaria alexandrina snails. The high concentrations of the three tested agents caused a remarkable reduction in hatchability percent of B. alexandrina eggs than the low concentrations. The sublethal concentrations (LC 10 and LC 25) of both A. densiflorus and Score have more destructive effect on the survival, growth and reproductive rates of the juvenile snails than the corresponding concentrations of O. guatemalensis plant. Different sublethal concentrations (LC o and LC 5) of the three agents caused a remarkable elevation in the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes of the snails after the 1 st week of the exposure. The sublethal concentration LC5 of the three tested agents caused pronounced effect on the alkaline phosphatase (ALP) and acid phosphatase (ACP) activities after the 2 nd weeks of the exposure. Total protein, albumin, globulin and albumin/ globulin (A/G) ratio in hemolymph of snails exposed to sublethal concentration LCo of the three tested agents, are differently affected after the 1 st and 2 nd week of the exposure. The histological examinations demonstrated a severe damage in both secretory cells and digestive cells especially in case of Asparagus densiflours and Score.