Removal of the eyestalks of the prawn Penaeiis indiciis resulted in an

increase in the haemolymph-sodium level. This increase was more evident in

bilaterally ablated animals. Injection of eyestalk extract into destalked animals

helped them to restore the level almost similar to that of normal animals

Diwan, A D

Kiron, V

CMFRI Digital Repository

THE INFLUENCE OF EYESTALK ABLATION ON THE REGULATION OF HAEMOLYMPH SODIUM CONCENTRATION IN THE PRAWN PENAEUS INDICUS H. MILNE EDWARDS V. KiRON AND A. D. DlWAN Centre of Advanced Studies in Mariculture, C. M. F. R. Institute, Cochin. ABSTRACT Removal of the eyestalks of the prawn Penaeiis indiciis resulted in an increase in the haemolymph-sodium level. This increase was more evident in bilaterally ablated animals. Injection of eyestalk extract into destalked animals helped them to restore the level almost similar to that of normal animals. INTRODUCTION Crustaceans are charaterized by a wide range of osmoregulatory powers, which are developed based on the environment to which the animals are adapted. The capacity to regulate the ions aids the prawns in the successful completion of their life history in the wide-differing aqua-regions, viz., the sea and the estuary. The ionic ability seems to be a purely adaptive feature that may change markedly during development according to environmental needs (Dall 1981). The involvement of endocrine factors in hydromineral regulation in decapod crustaceans have been demonstrated experimentally from early works of Scudamore (1947) to more recent works of Charmantier et al (1981). Early workers like Carlisle (1955) on Carcinus sp. and Bliss et al (1966) on Gecarcinus lateralis succeeded in establishing the possible role of endocrine factors in water uptake during molting process. Kamemoto et al (1966) and TuUis and Kamemoto (1971), working on the crabs, Metapograpsus messor and Thalamita crenata, respectively, have concentrated their efforts on the control of salt and water balance by the brain and thoracic ganglion. Schreiner et al (1969) recorded the importance of the abdominal ganglion in water balance in Homarus sp. Information is scanty on the neuroendocrine factors controlling specific ions in the haemolymph of crustaceans. The sodium regulation in an eyestalkless crab, Uca pugilator, was studied by Heit and Fingerman (1975). In the present work the possible role of the eyestalk in regulating the important anion such as sodium was investigated. The Indian white prawn, Penaeus indicus, was chosen as the experimental animal due to its good osmo-regulatory capacity both inestuarine and marine environment. EYESTALK ABLATION AND SODIUM REGULATION 245 MATERIAL AND METHODS The adult Penaeus indicus for the present study were collected from traditional impounciments adjacent to Cochin backwaters. The animals in the intermolt stage and of uniform size having a length of about 100 ± 10 mm were selected. Sea water used was adjusted to a salinity of 25 ± 1 ppt., filtered and kept aerated. The animals were acclimatized to the above salinity for a period of 48 h to maintain an isosmotic state before starting the experiment. When being acclimatized, they were not fed, 'save for cannibalism'. The individual animals were maintained in circular plastic tube of 10-1 capacity. The experiments were designed mainly on the eyestalk removal tech-nique.. Four batches of twenty animals each were maintained. Of this twenty, ten were experimental and ten control with intact eyes. In the first batch of animals one eyesta'k was removed. Simultaneously, in the second batch, both eyestalks were ablated. In the third and fourth batch also both eyestalks were removed and they were injected with eyestalk extract and distilled water res-pectively. After initiation of experiment, the first haemolymph sample was collected immediately. The next sample was after 1 h, and then subsequently after 2nd, 4th, 6th, 8th, 12th, 16th, 20th and 24th h from animals of all batches. Haemolymph was collected using a 1-ml tuberculin syringe equipped with a 22-guage needle; from the suprabranchial and also from the cardiac region. The experiments were rcipeated four times. Analysis of sodium was carried out im-mediately to avoid the use of anticoagulant. Eyestalk extract for injection was prepared in the ratio of 2 eyestalks|0.2 ml of distilled water and each ablated animal was injected 0.2 ml on the first abdominal segment. Sodium concentration was determined using Elico digital flame photo-meter model No. C'L 22D. Students t-test was used to analyse the significance of the variation of sodium levels from the control animals. RESULTS The variations of the sodium ionic level in the haemolymph were studied by comparing the levels in the experimental animals with that of control animals and its is presented in Table 1. In the unilaterally ablated animal the haemolymph showed a decreased sodium ionic level in the beginning, which increased to a high level and maintained high then onwards with slight fluctuations. The values remained high through-out the period with significant difference at the sixteenth hour (Fig. 1). The ionic level of sodium in the haemolymph of bilaterally ablated animal was higher than that of control up to the sixteenth hour after ablation and, thereafter, the values fell, but remained high compared to control animals. Most valu(;s under this treatment were significant at P ^ 0.05 level (Fig. 2) . 246 KIRON AND DIWAN TABLE 1. Sodium ion concentration in the haemolymph of P. indicus under different treatments. (in milli equivalentsjlitre) Hours 0 1 2 4 6 8 12 16 20 24 Unilateral ablation _ Xe 422 (33) 422 (16) 447 (11) 432 (10) 437 (12) 443 (27) 441 (17) 439 (5) 436 (7) 435 (6) ^^ Xc 430 (4) 426 (11) 435 (10) 430 (7) 430 (5) 433 (5) 434 (5) 430 (4)* 431 (5) 430 (5) Bilateral ablation _ Xe 413 (24) 464 (12) 448 (4) 468 (18) 462 (8) 464 (4) 452 (5) 457 (5) 442 (7) 440 (5) , Xc 428 (6)* 430 (12)* 437 (11) 431 (6)* 429 (2)* 428 (3)* 428 (5)* 430 (5)* 431 (5) 430 (5)* Bilateral ablation + extract injection Xe 457 (5) 433 (21) 455 (11) 446 (13) 442 (16) 432 (31) 432 (25) 431 (17) 430 (15) 436 (15) Xc 431 (4)* 430 (10) 435 (8) 431 (7) 430 (6) 428 (8) 433 (5) 421 (6) 431 (3) 432 (5) Bilateral ablation + ii Xe 400 (4) 459 (3) 462 (23) 453 (11) 440 (4) 430 (7) 438 (2) 442 (9) 439 (9) 437 (16) water ijection „ Xc 431 (4)* 430 (10)* 436 (8) 431 (6) 430 (6) 428 (8) 432 (5) 420 (6) 431 (3) 432 (4) Xg - Mem experimental values \Q - Mean control values * = Difference X^ - X'c significant at P = 0.05. Numbers in parentheses are the standard deviations. 30 £ '° control * value % - 0 -30 '•>— obt t rv id trand opproKlmated trtnd . jignHlconl, P « 0 0 5 0 I 2 4 6 S 12 16 20 2* hours otter intiotion of experiment FIG. 1. Difference from the con-trol in the variation of sodium levels in the haemolymph of an unilaterally ablated P. indicus. 4 0 - 30 E 10 3 value 1 -10 -20 - S O ---/ • • l 1 ^ — observtd trend opproiimdtdd tr«nd • s igni f icant , P « 0 05* »^^ V x::^  I I . 1 1 1 1 1 1 0 I 2 4 6 a 12 16 20 24 hours offer i r t iot ion of experiment FIG. 2 Difference from the con-trol in the variation of sodium levels in the haemolymph of a bilaterally ablated P. indicus. EYESTALK ABLATION AND SODIUM REGULATION 247 In the bilaterally ablated, eyestalk-extract-injected animal, the difference in the sodium levels of the experimental and control animals was insignificant (P > 0.05), except at the initial observation. The levels in the experimental animals resembled those of control towards the terminal part of the experiment (Fig. 3). —— oDserved trend - - - opproKimoted trend • jigniticont, P = 0 05 _ so S 20 e 10 Econtrot 3 valut ^ -'" - 2 0 -SO observed trend - - • opprosimoted trend • significont, P^O 0 5 - X^ :^,^ .^^  " ^ • < ^ ; X ^ ^ w -— 1 . 1 1 1 , 1 1 1 1 0 I 2 'I 6 a 12 16 20 24 hours after t- it iati on of experiment FIG. 3. Difference from the con-trol in the variation of sodium levels in the haemolymph of a bilaterally ablated extract injec-ted P. indicus. 0 I 2 4 6 e 12 16 20 24 hours otter intiotion ol enpennnenl FIG. 4. Difference from the con-trol in the variation of sodium levels in the haemolymph of a bilaterally ablated water injected P. indicus. When watei was injected to a bilaterally ablated animal, most of the observations were higher than the control (Fig. 4). DISCUSSION The most important ions involved in the maintenance of osmotic balance are the sodium and chloride. The exchange of these ions results from passive diffusion in an isosmotic medium as has been shown in Carcinus maenas (Shaw 1955, 1961; Zanders 1980), Hemigrapsus sp. and Pachygrapsus crassipes (Dehnel and Carefoot 1965; Rudy 1966). Webb (1940) and Shaw (1961) have suggested that a small amount of active uptake of sodium ion is involved in its distribution between the medium and the haemolymph in crab Carcinus maenas. The regulation of ions seems to be in response to a common factor like haemolymph-sodiuffi concentration, the total ion concentration, or the osmotic pressure of the haemolymph. This process may be under a primary controDer which could be hormonal (Zanders 1981). Heit and Fingerman (1975) had already established the role of the eyestalk hormone in controlling the sodium concentration of th(; haemolymph in Uca pugilator. They found that bilateral eyestalk removal frcm crabs in hyposmotic medium resulted in a significant drop in the haemolymph levels. When they were in an isosmotic medium the drop was not significant. Eyestalk-extract injection restored the sodium levels of eyestalk-less crabs to that of intact ones. Further, the authors have confirmed a sodium-decreasing hormone in the eyestalk and concluded that the effectiveness of the 248 KIRON AND DIWAN eyestalk extract in increasing the sodium level decreased as the sodium concent-ration of the medium increased. In the present study, it was revealed that the Removal of the eyestalk resulted in an increase in the haemolymph concentration of sodium ions. An initial lowering was evident under all treatments except the extract injection. This may probably be due to the shock of ablation. In the case of unilaterally ablated prawns the haemolymph values did not show wide fluctua-tions compared to bilaterally ablated animals. The sodium-decreasing hormone present in one eye may be acting to prevent the imbalance caused by ablation. In the case of bilateral ablation the sodium level increased significantly from low values to figures greater than the control. The removal of a sodium-decreasing factor causes an increase in the sodium content of haemolymph. Moreover, the treatment might also aid the dominance of sodium-increasing factors, which might be synthesized in other parts of endocrine system like cerebral and thoracic ganglia of the animal. Kamemoto et al (1966) described a similar haemolymph sodium-increasing factor in the brain of Procambarm clarkii. In the destalked animals injected with extract, the sodium concentration which was high initially dropped gradually and behaved almost similar to that in normal animals. The sodium concentration in these animals clearly indicated that the level came down only because the extract was injected. This revealed the capacity of the eyestalk hormone in decreasing the haemolymph value. The destalked animals injected with water behaved like the bilaterally ablated animal, but, in them, the deviation of the sodium values from the control was restricted. The eyestalk removal thus results in the loss of capacity for sodium regulation. No reliable information is available about the mechanism of eyestalk hormones in ionic regulation. The sodium controlling hormones may be acting on the body surfaces and excretory organs. At the body surfaces it would decrease the outward permeability of the epithelial cells while at the same time promoting the active uptake of sodium across the gills by stimulating a Na ' -K ^  activated ATPase such as was found in the gills of the terrestrial crab, Cardio-som quanhumi, by Quinn and Lane (1966). Sodium retention may also be tak-ing place in the excreatory organs. Sodium regulation in Penaeus indicus assumes importance due to its life phases in the diverse salinities. Further investigation is warranted to show how the hormones deploy the ion regulating systems. ACKNOWLEDGEMENT We express our deep sense of gratitude to Dr. E. G. Silas, Director, Cen-tral Marine Fisheries Research Institute, Cochin, for providing the necessary facilities to carry out the present work and his constant encouragement. Our thanks are also due to Sri. K. N. Kurup. Scientist, CMFRI, for helping in stati-stical calculations. The Junior author (VK) wishes to express his sincere thanks to ICAR for awarding a junior research fellowship during the tenure of the work. EYESTALK ABLATION AND SODIUM REGULATION 249 REFERENCES Buss, D. £., S. M. E WANG AND F . A. MARTINEZ. 1966. Water balance in the land crab Gecarciniis lateralis during the intermolt cycle. Amer. Zool., 6, 197-212. CARLISLE, D . B . 1955. On the hormonal control of water balance in Carcinus. Pubbl. Staz. Zool. Napoli., 27 227-231. CHARMANTTER DE GUY, MIREILLE CHARMANTIER-DAURES AND D . E. AIKEN. 1981. Con-trole neuroendocrine de la regulation osmotique et ionique chez les juveniles et les larves de Homarus americaniis H. Milne EdWards. C. R. Acad. Sc. Paris, t. 293, 831-834. DALL, W. 1981. Osmoregulatory ability and juvenile habitat preference in some penaid prawns. / . exp. mar. Biol. EcoL, 54, 55-64. DEHNEL, P . A . AND T . H . CAREFOOT. 1965. Ion regulation in two species of intertidal carbs. Comp. Biochem. Physiol, 15, 377-397. HBIT, M . AND M . FINGERMAN. 1975. The role of eyestalk hormone in the regulation of the sodium co icentration of the blood of the fiddler crab, Uca pugilator. Comp. Biochem. Physiol, 50, 277-280. KAMEMOTO, F . I., K. N. KATO AND L. E . TUCKER. 1966. Neurosecretion and salt and water balance in Annelida and Crustacea. Amer. Zool, 6, 213-219. QUINN, L . E . AND C. E. LANE. 1966. Ionic regulation and Na+ —K+ stimulated ATPase activity in the land crab. Cardiosoma quanhnmi. Comp. Biochem. Physiol, 19, 533-543. RUDY, P. P. 1966. Sodium balance in Pachygrapsus crassipes. Comp. Biochem. Physiol, 18, 881-907. SCHREINER, B., H. SWALAND AND A. S. JoHANSON. 1969. Functional significance of neuro-secretory cells in the last abdominal ganglion of the lobster Homarus vulgaris L. Gen Comp. Endocrinol, 13, 399-402. ScuDAMORE, H. H. 1947. The influence of the sinus gland upon the mohing and asso-ciated changes in the crayfish. Physiol. Zool, 20, 187-208. SHAW, I. 1955. Ionic regulation in the muscle fibres of Carcinus maenas. II. Effect of reduced blood concentration. /. exp. Biol, 32, 664-680. SHAW, J. 1961. Studies on the ionic regulation of Carcinus maenas (L) I. Sodium balance / . exp. Biol, 3 3, 135-152. TuLLis, R. E. AND F . I. KAMEMOTO. 1971. CNS factors affecting water movement in decapod crustaceans. Amer. Zool, 11, 646-651. WEBB, D . A. 1940. Ionic regulation in Carcinus maenas (L) Proc. R. Soc. B., 129, 107-136. ZANDERS, I. P. 1980. Regulation of blood ions in Carcinus maenas (L) Comp. Biochem. Physical, 65, 97-108. ZANDERS, I. P. 1981. Control and dynamic of ionic balance in Carcinus maenas (L). Comp. Biochem. Physiol, 70, 457-468. 

The influence of eyestalk ablation on the regulation

Of haemolymph sodium concentration in the prawn

Penaeus indicus H. Milne Edwards

http://eprints.cmfri.org.in/447/1/Article_09.pdf

The influence of eyestalk ablation on the regulation Of haemolymph sodium concentration in the prawn Penaeus indicus H. Milne Edwards

Abstract

Similar works

Full text

Available Versions

CMFRI Digital Repository