Lipid and Polypeptide Profiles in the Female Portion of Gonads from Diet-Conditioned Broodstock of North Chilean ScallopsArgopecten purpuratus

Abstract

Broodstock of North Chilean scallops Argopecten purpuratus were transferred from Tongoy (30Њ16ЈS, 71Њ32ЈW) to Dichato (36Њ32ЈS, 72Њ57ЈW), Chile, to be conditioned in a hatchery. The scallops were subjected to four different microalgal feeding treatments for 45 d. The feeding treatments were as follows: (1) equal parts of Isochrysis galbana and Dunaliella tertiolecta, (2) equal parts of I. galbana, Chaetoceros gracilis, and D. tertiolecta, (3) equal parts of I. galbana and C. gracilis, and (4) equal parts of C. gracilis and D. tertiolecta. All microalgae were collected in the exponential phase of growth (feed quantities, 1-3 ϫ 10 5 cells/mL) in the hatchery. One group of scallops kept in ''lanterns'' in the sea served as a control. After 20 and 45 d of conditioning, gonad samples were taken from both immature and mature scallops (distinguished by coloring) from the treatment and control groups for biochemical analysis. Higher-molecular-weight polypeptides (72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83)(84)(85)(86)(87)(88)(89) in the treatment groups and 69-107 kDa in the control group) were found more frequently in mature than in immature scallops. Moreover, a greater amount of polypeptides of a higher total molecular weight was observed in mature gonads. Polypeptide quality was unaffected by treatment but differed from that of scallops in the control group. Polypeptides of specific molecular weights in each maturity stage were detected. Although the quantity of total lipid was high in both treatment and control scallops, qualitative and quantitative differences in several fatty acids were observed. The presence of 20:5, 22:6, and 18:3 (where the number before the colon is the number of carbon atoms and the number after the colon is the number of double bonds) shows that the development of female gonads was good when the scallops were fed I. galbana and C. gracilis. Female gonad development was similar in scallops fed D. tertiolecta and C. gracilis.to the next. Therefore, it is necessary to condition adults to develop high-quality gonads that produce gametes throughout the year. It is also important that the gametes produced by hatchery broodstock be in good condition to ensure high survival of the larval stages, with high growth ratios and more resistance to bacterial and fungal diseases. Physical (temperature) and nutritional factors are important to the successful conditioning of a scallop broodstock. Spawners fed an adequate diet that is rich in proteins and polyunsaturated fatty acids

Reproductive Conditioning of the Peruvian Scallop Argopecten purpuratus in Different Environments

“…This conclusion is supported by the findings of [49], who indicated that lipids contributed the greatest percentage (46.7%) of the energy required for embryogenesis, followed by proteins and carbohydrates, which contributed 43.5% and 9.8%, respectively. A diet rich in a variety of microalgae, particularly diatoms and green algae, is essential to produce high-quality oocytes and to improve the reproductive performance of scallops in hatcheries [50]. Regarding the size of "D" larvae, there were significant differences between the two treatments -natural environment and hatchery conditions-with sizes reaching 95.8 ± 3.1 µm and 91.2 ± 2.7 µm, respectively.…”