Changes in the biochemical composition of the pyloric ceca of female sea stars asterias rubens during their annual reproductive cycle
Oudejans, R.C.H.M.; Van Der Sluis, I.; Van Der Plas, A.J.
Marine Biology 53(3): 231-238
ISSN/ISBN: 0025-3162 Accession: 004912982
The biochemical composition of the pyloric ceca of female seastars (A. rubens) was studied throughout the annual reproductive cycle. The pyloric ceca index is high during the pseudo-rest stage of the ovaries and decreases gradually during ovarian growth. The pyloric ceca dry weight varies 20-38% of the fresh weight. Lipids and less prominently carbohydrates (both glycogen and other reducing sugars) seem to constitute the primary nutrient reserves for gonad growth. Proteins are also available to meet ovarian requirements during vitellogenesis. Glycogen levels are high in late autumn and winter and low at spawning time and in summer, whereas levels of the other reducing sugars are high in post-spawning months and subsequently gradually decrease during gonad development. The total lipid level is extremely variable (averaging 75 mg/g organ fresh weight), peak levels of over 200 mg/g being found in some individuals in summer and at spawning time. The free amino acid level is constant at .apprx. 20 mg/g. The protein level is rather high throughout the annual cycle, and displays only minor changes. The observed patterns of decrease in major constituents suggest a rapid release of nutrient reserves from the pyloric ceca (deposited during the summer) at the onset of vitellogenesis. The needs of the ovaries during further development seem to be so tremendous that during the winter months the digested food may be transported to the ovaries without prior deposition in the pyloric ceca. The changes observed in the pyloric ceca are discussed and compared with those occurring simultaneously in the ovaries.