The Preliminary Study Of Nutritional Value Evaluation, Heavy Metals Purification And Breathing Mechanism Of Onchidiidae

Onchidiid belongs to Mollusca, Gastropoda, Pulmonata, Stylommatophora,Onchidioidea, Onchidiidae which is naked and with lungs. The habitat of Onchidiid islittoral-marine and the animal divides its existence between life in the water and in theair. Onchidiid has high nutritional value and economic value, and the breathingmechanisms of biological evolution from the ocean to the land also has importantresearch value. In order to further understanding the food safety and breathingmechanisms of Onchidiidae，We did a study of the nutrient content of Onchidiidae andits value assessment，the situation of heavy metals in excess and its purification and alsothe oxygen consumption rate. The main results of this study were as following:（1）Nutrients of muscular index, moisture, ash, crude protein, crude lipid, totalsugar, amino acids, mineral contents are determined in four species of Onchidiidaeinclude Paraoncidium reevesii, Platevindex mortoni, Peronia verruculata (Zhangjiang,Guangdong)and Onchidium struma (Chongming, Shanghai). The results showed that:general nutritional composition exist significant difference, but four species ofOnchidiidae are all high in protein, low in fat, rich in moisture and mineral elements.Mineral elements content in muscle tissue of four species of Onchidiidae were very rich,especially the content of Ca, Mg were particularly high. Four species of Onchidiidaehad high protein content in muscle tissue, protein amino acid compositioncomprehensive, high levels of flavor amino acids, essential amino acid content in linewith the FAO/WHO ideal mode, the proportion of essential amino acid composition isgood, and abundant mineral elements. Four species of Onchidiidae had a high nutritional value, and they could be as specialty seafood or upscale tonic.（2）The purification effect of the exceeding Cd and Cu in Onchidium struma by addingMuyu-Stone which is rich in Zn and Se to the habitat sediment or adding Cholorellapyrenoidosa powder and Vitamin C in the feed was compared in order to find out thebest one. The results showed that corn flour alone had certain effect on the discharge ofheavy mental in control group, but it was far less than the one of Muyu-Stone,Cholorella pyrenoidosa powder and vitamin C in experimental group. The contents ofheavy mental Cd and Cu in O. struma were efficiently reduced, so this method can beapplied in the producting process to guarantee the food safety.（3）The underwater oxygen consumption rate of Onchidium struma, Platevindexmortoni, Paraoncidium reevesii and Peronia verruculata were determined. The resultsshow that unit weight of epidermis respiratory oxygen consumption rate of four speciesof Onchidiid decreased with increasing body weight; comparison of the oxygenconsumption rate of four species of Onchidiid under the same conditions, the oxygenconsumption rate of P. verruculata，O. struma and P. mortoni were minimize in the thirdhour, respectively（0.126±0.014）mg/(g·h),（0.111±0.011）mg/(g·h),（0.081±0.006）mg/(g·h). The one of P. reevesii reach the minimum of （0.098±0.015）mg/(g h) in thefourth hour. P. verruculata has a significantly higher oxygen consumption rate than theother three species. When Onchidiid are underwater, their epidermis is used as therespiratory organ, also the dendritic gill of Peronia verruculata also involved inbreathing.