Lipid
and polypeptide profiles in the female portion of gonads from
diet-conditioned broodstock of North Chilean scallops Argopecten purpuratus
J. Cerpa, F. Gonzalez, J. Becerra, I. Lepez-2003
North
American Journal of Aquaculture, 65(1) : 1-7
Abstract:
Broodstock of North Chilean scallops Argopecten
purpuratus were transferred from Tongoy (30°16'S, 71°32'W) to Dichato (36°32'S,
72°57'W), 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 X 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 (7289
kilodaltons [kDa] 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.
(Concepcion Univ., Genet. Lab., Dept. Biol. Mol.,
Fac. Ciencias Biol., Casilla 160-C, Chile, e-mail of F. Gonzales: fgonzale@udec.cl)