Now showing items 1-3 of 3

    • Article

      Effect of salinity on hemolymph calcium concentration during the molt cycle of the prawn Penaeus monodon 

      FD Parado-Estepa, JM Ladja, EG de Jesus & RP Ferraris - Marine Biology, 1989 - Springer Verlag
      Prawns (Penaeus monodon) were obtained from ponds in Iloilo, Philippines, in 1984 and 1985 and maintained in salinities from 8 to 44‰. Total hemolymph calcium was largely affected by molt stage and less so by salinity. A sharp, transient increase in hemolymph calcium occurred 3 to 6 h postmolt, followed by an equally rapid decrease from 6 h postmolt to intermolt. This biphasis response was limited to prawns in 8, 20 and 32‰S; in 44‰S, hemolymph calcium remained the same throughout the sampling period. Peak concentrations of total calcium were greater in low (8 and 20‰S) than in high salinities. Salinity had no effect on the duration of molt cycle nor on time of occurrence of molt. Almost half of molting incidents occurred between 18.01 and 0.00 hrs, and one-third between 0.01 and 06.00 hrs.
    • Article

      Effect of salinity on the osmotic, chloride, total protein and calcium concentrations in the hemolymph of the prawn Peneaus monodon (Fabricius) 

      RP Ferraris, FD Parado-Estepa, JM Ladja & EG de Jesus - Comparative Biochemistry and Physiology - Part A: Physiology, 1986 - Elsevier
      1. Osmolality and chloride concentrations in the hemolymph of Penaeus monodon became stable 1 day after molting in 32 ppt, while total protein and calcium concentrations remained stable throughout the molting cycle. When intermolt (≥ 36 hr postmolt) animals were transferred from control (32 ppt) to experimental (8–40 ppt) salinities, osmolality, chloride and total protein, but not calcium, concentrations in the hemolymph achieved steady state values 24–48 hr after transfer.

      2. The hemolymph osmolality was a linear function (slope = 0.28) of medium osmolality at salinities between 8 and 40 ppt. It was isosmotic to seawater at 698 mOsm (10 g prawns) and 752 mOsm (30 g), and was hyperosmotic to the medium below isosmotic concentrations, and hypoosmotic to those above.

      3. Hemolymph chloride concentration was isoionic to seawater at 334 mM, and was hyperregulated below isoionic concentrations, and hyporegulated to those above.

      4. P. monodon maintained its hemolymph calcium concentration between 6.4 and 10 mM when medium salinities increased from 8 to 40 ppt.

      5. Total protein concentration in the hemolymph was independent of medium salinity (8–40 ppt) and hemolymph osmolality (540–850 mOsm).
    • Article

      Ovarian changes and female-specific protein levels during sexual maturation of the white shrimp Penaeus indicus 

      ET Quinitio & OM Millamena - The Israeli Journal of Aquaculture-Bamidgeh, 1992 - Society of Israeli Aquaculture and Marine Biotechnology
      The histological changes in the ovary and female-specific protein levels in the hemolymph during sexual maturation of Penaeus indicus were determined. Ovarian maturation was classified into four stages: immature stage, consisting mainly of oogonia and primary oocytes; maturing stage, composed of oocytes with yolky substances in the cytoplasm; mature stage, oocytes with club-shaped cortical rods in the peripheral cytoplasm; and spent stage, composed of primary oocytes, oocytes with yolky substances and scattered residual rod-like bodies.

      Female-specific protein levels in the hemolymph were low in the immature stage (4.45 µg/ml), increased significantly in the maturing stage (23.53 µg/ml), peaked in fully mature (48.30 mu g/ml) and decreased in spent (22.86 µg/ml) females.