Biochemical composition and energy sources during embryo development and in early juveniles of the snail Pomacea canaliculata (Mollusca: Gastropoda)

Abstract

Energy partitioning within the developing eggs and early juveniles of the gastropod Pomacea canaliculata was investigated from the time of fertilization to newly hatched snails. The forms and locations of the energy stored as well as their changes while development proceeded were studied in six stages (from morula to 3-day hatchlings). The rates of utilization of different lipid classes, protein classes, and total carbohydrates were measured for the first time in embryos and perivitelline fluid.Perivitelline fluid is the primary energy store. Its biochemical composition at stage I is represented by carbohydrates, proteins, and lipids with 34.8%, 13.0%, and 1.5% dry weight, respectively. Dry weight of eggs showed no significant increase during development, indicating there was no important mass exchange with the medium.Carbohydrates and proteins were identified as the major energy-providing components, and lipids as the minor one, contributing 142, 56, and 12 cal/100 mg egg, dry weight, respectively. The overall conversion efficiency (CE) was 32.8% (calculated as percentage of perivitellus energy transformed into embryonic tissues). Carbohydrates were the most important energy reserve supplying virtually all the catabolic demand (CE 14.6%).Protein electrophoretic profiles during embryogenesis showed three distinct phases: An accumulation period (up to stage IV); a more active accumulation and selective utilization phase (stage V), and a selective consumption and protein synthesis period (hatchlings). Structural lipids from perivitellus (phospholipids and free sterols) were selectively conserved in embryos and juveniles, whereas triacylglycerols, hydrocarbons, and esterified sterols were preferentially depleted by hatchlings.Therefore, protein and lipid reserves in P. canaliculata perivitellus provide structural precursors during embryogenesis, while they partially contribute to the energy supplied by carbohydrates.

Effects of food availability on reproductive output, offspring quality and reproductive efficiency in the apple snail Pomacea canaliculata

“…Survival times of several weeks have been reported for starving adult and juvenile P. canaliculata , but no data were available hitherto for hatchlings, which depend only on the perivitelline egg reserves stored in their mid-gut gland (Heras et al 1998;Koch et al 2009). Hatchlings showed a high resistance to starvation, with median survival times longer than 3 weeks and individual maximum values of up to 80 days, a capacity probably relevant to their establishment in habitats in which food availability is low or highly variable.…”

Assessment of Nontoxic, Secondary Effects of Sorbent Amendment to Sediments on the Deposit-Feeding Organism Neanthes arenaceodentata

“…19 Results were tested for homogeneous variances, compared by ANOVA testing and post hoc multi comparison tests (Microsoft Excel XLStat, 1995−2011).…”

Influence of Temperature, Size and Sex on Aerial Respiration ofPomacea canaliculata(Gastropoda: Ampullariidae) from Southern Pampas, Argentina

“…During development, the embryos them with structural precursors and energy supplies (Heras et al, 1998) until eggs hatch by mechanical fracture of the calcareous egg shell. It seems highly improbable that the stages of development when the perivitelline it is unknown whether lung ventilation begins just before falling from the egg mass or, alternatively, how long after the snails have fallen into the water.…”