Search

Marine snails provide an important source of vitamins, proteins, minerals, and essential fatty acids, and their mucus has a therapeutic significance. Parasitic infection of larval trematodes in these snails affects their nutritional value. The present study aimed to screen Nerita polita marine snails for the prevalence of cercarial infections and to evaluate the changes in lipids and some minerals in the infected as well as non-infected ones. Snails were collected randomly from February 2018 to January 2019 from the Red Sea Obhor bay, Jeddah city, Saudi Arabia. The amount of triglycerides, cholesterol, and phospholipids in the Digestive Gland Gonad Complex (DGG), hemolymph, and Snail Conditioned Water (SCW) of non-infected and infected Nerita polita snail was estimated using a spectrophotometer. Minerals content such as Ca, Zn, Pb, Na, Mn, Mg, K, Fe, Cu, and Cd, in the DGG and shell in the infected and non-infected snails were analyzed using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Two types of cercariae were detected, ocellate furcocercus cercaria (Trichobilharzia regent) and xiphidiocercaria (Litorina saxatilis VII). The study showed that there is a fl uctuation in the concentration of lipids and minerals between increase and decrease in DGG, hemolymph, shell, and SCW in infected snails. The nutritive value of the snails is affected with infection through the decrease of some lipids and minerals in infected snails. Further qualitative studies are needed.

Neritas are among the most dominant groups of Gastropoda in the Persian Gulf. There is no previous study in relation to molecular and phylogeny of Neritas in the study area. The molecular identification of Nerita species have been studied for the first time in the northern rocky coastal zones of Persian Gulf during 2013 and 2014. After morphological identifications of species, DNA extraction, amplifying partial of cytochrome oxidase COI and 16S rRNA and sequencing procedure were done in the laboratory. In this study, 6 COI and 6 16S rRNA sequences, belonging to 3 species, were obtained. Also, phylogeny analyses with drawing phylogeny trees of Maximum Likelihood and Bayesian were done using MEGA6 and BEAST softwares. Morphological and molecular identification results were similar for 2 species and dissimilar for one species. This discrepancy shows that a combination of morphological and molecular studies is more reliable for species identification than either of them solely. The results also showed that Nerita species are monophyletic.