Histopathological Changes in Tissues and Rate of Mortality of Golden Apple Snails (Pomacea Canaliculata) Exposed to Tuba-Tuba (Jatropha Curcas) Bark Crude Extracts

Abstract

INTRODUCTION

Golden apple snails (GAS) are voracious freshwater mollusks that feed on freshwater flora, especially rice shoots. According to the UN Food and Agriculture Organization (2016), 1-40% of Philippine rice fields were damaged by GAS, causing huge production loss. Other control methods include predators and synthetic pesticides, which promotes partial mortality but presents severe problems like ecosystem disruption and food poisoning. Tuba-tuba boasts potential molluscicidal properties and is locally available. The Organic Agriculture Act of 2010 promotes organic farming and that the use of organic fertilizers and pesticides are relevant at present. The primary aim of the study was to determine the histopathological changes in tissues, and the mortality rate of GAS when exposed to Tuba-tuba bark crude extracts.

METHODS

Randomized Complete Block Design (RCBD) was used to gather relevant quantitative data for the study. The processes chronologically used in this study are the Preparation of GAS, Crude Extraction, Maceration, Steam Distillation, GAS Acclimatization, Crude Extract Induction, Tissue Sections Preparation, Staining, and Histopathological Observations. GAS samples were collected by scooping them out from the freshwater reservoir and were moved to a 20-liter tank. After several procedures, they were incubated with different concentrations (25%, 50%, 75%, 100%) of Tuba-tuba bark crude extracts (Rawi et al., 2011).

RESULTS

Exposure of GAS to Tuba-tuba bark crude extracts for 24 hours caused moderate to severe destructive effects in the body tissues, evident in both LC 50 and LC 90, and were seen in the histopathological findings. There is necrosis of the gills, degeneration of foot muscle fibers, closing of opercula, erosion of the lining epithelium of the digestive tract and increased hemolymphatic gaps. For 24 hours, the mortality rates for Treatments 1-5 are 0%, 47%, 80%, 100% and 100%, respectively.

DISCUSSIONS

The study showed that Tuba-tuba bark crude extracts necrotized the snails' foot, digestive tract, and gills and increased their hemolymphatic gaps at different concentration levels. According to El-Din (2011), at all stages, snail mortality increased due to the increasing plant extract concentration. Studies are needed to determine the exact substance or mechanism for snail mortality. Field studies are also needed to confirm the viability of the plant extract. This study would then help fill the knowledge gaps regarding the medicinal and chemical properties of Tuba-tuba bark crude extracts.