Jean-Paul Trilles

Effect of copper on survival and osmoregulation of various developmental stages of the shrimp Penaeus japonicus bate (Crustacea, Decapoda)

The object of this study was to evaluate the acute toxicity of cadmium in different post-embryonic stages of the penaeid shrimp Penaeus japonicus (Bate, 1888) and to determine the effect of sublethal cadmium on the osmoregulatory capacity used as an indicator of physiological condition. Tolerance to cadmium increases with the developmental stage. The least tolerant stages are the nauplii (48 h LC50: 124 μg Cd l-1) and the zoeae (96 h LC50: ≃10 to 30 μg Cd l-1). The most tolerant stages are the postlarvae (96 h LC50: ≃200 to 3500 Cd l-1) and juveniles (96 h LC50: 5500 μg Cd l-1). In juvenile shrimp, 2000 μg Cd l-1 significantly reduce hypo- and hyper-OC. The effect of cadmium on hypo- and hyper-osmoregulatory capacity illustrates a dose- and time-dependent response. Surviving shrimp recover their hypo-osmoregulatory capacity after 6 d of readaptation in cadmium-free seawater.

Impact of cadmium on the structure of gills and epipodites of the shrimp Penaeus japonicus (Crustacea: Decapoda)

The objective of this study was to investigate the impact of cadmium on the structure of gills and epipodites in late juvenile Penaeus japonicus. Cadmium titrations were performed by atomic absorption flame spectrophotometry, and structural observations were performed through light- and electron-microscopy. The cadmium concentration increased in different tissues (mainly gills, epipodites and hepatopancreas) according to the external cadmium concentration and the exposure time. The structural changes which occurred in the gill and epipodite cells appeared to be a function of cadmium accumulation in these tissues. Gill cells of shrimps exposed to 2 and 200 μg Cd·L−1 for 15 d did not display discernible structural changes. An increased number of nephrocytes was noted in gill filaments of shrimps exposed to 200 μg Cd·L−1. Exposure to 2 000 and 4 000 ug Cd·L−1 during 4 d resulted in profound structural changes. The epithelial cells were necrosed, disorganized and vacuolized. Exposure to 2 μg Cd·L−1 for 15 d did not result in discernible structural changes of epipodite cells. Exposure to 200 ·g Cd·L−1 for 15 d, 2 000 and 4 000 μg Cd·L−1 during 4 d induced profound alterations of the epipodites: increased thickness, decreased number of apical microvilli, basal infoldings and mitochondria, occurrence of pseudomyelinic structures. These alterations are discussed in relation to the respiratory and osmoregulatory functions of gills and epipodites.Abstract The objective of this study was to investigate the impact of cadmium on the structure of gills and epipodites in late juvenile Penaeus japonicus. Cadmium titrations were performed by atomic absorption flame spectrophotometry, and structural observations were performed through light- and electron-microscopy. The cadmium concentration increased in different tissues (mainly gills, epipodites and hepatopancreas) according to the external cadmium concentration and the exposure time. The structural changes which occurred in the gill and epipodite cells appeared to be a function of cadmium accumulation in these tissues. Gill cells of shrimps exposed to 2 and 200 μg Cd·L−1 for 15 d did not display discernible structural changes. An increased number of nephrocytes was noted in gill filaments of shrimps exposed to 200 μg Cd·L−1. Exposure to 2 000 and 4 000 ug Cd·L−1 during 4 d resulted in profound structural changes. The epithelial cells were necrosed, disorganized and vacuolized. Exposure to 2 μg Cd·L−1 for 15 d did not result in discernible structural changes of epipodite cells. Exposure to 200 ·g Cd·L−1 for 15 d, 2 000 and 4 000 μg Cd·L−1 during 4 d induced profound alterations of the epipodites: increased thickness, decreased number of apical microvilli, basal infoldings and mitochondria, occurrence of pseudomyelinic structures. These alterations are discussed in relation to the respiratory and osmoregulatory functions of gills and epipodites.

Utilization of synthetic carotenoids by the prawn Penaeus japonicus reared under laboratory conditions

Abstract Four groups of prawns fed three different pigmented diets (astaxanthin 100 mg/kg, canthaxanthin 100 mg/kg, astaxanthin/canthaxanthin 50 50 mg/kg) and a pigment-free diet were maintained under laboratory rearing conditions during one moulting cycle. Dietary astaxanthin was found to be stored in the integument (carapace and epidermis) and hepatopancreas. Individuals fed the astaxanthin/canthaxanthin mixture showed an accumulation of carotenoids in the epidermis and exhibited the highest survival rate. There was no experimental evidence supporting a possible influence of these pigments on growth under the conditions used in this study.

A checklist of the Cymothoidae (Crustacea, Isopoda) recorded from Indian fishes

A checklist of the parasitic Cymothoidae of Indian fishes was compiled from parasitological records published between 1783 and 2011. The checklist is arranged alphabetically, providing valid names, synonyms and authorities of the parasite species, as well as valid names and synonyms of the host fish, its capture sites, author(s) and date of published records. The host list consists of all parasites species listed under the host species. A total of 47 nominal species corresponding to 36 valid species are listed from 74 host species belonging to 34 families. Several parasites not identified to species level and parasite species without the host data or where the parasite was found not associated with a fish are also included in this checklist.

Les Cymothoidae (Isopodes parasites de poissons) des côtes tunisiennes: écologie et indices parasitologiques

The study of the cymothoid isopod parasites on marine fishes from Tunisian localities has allowed us to distinguish eight species, seven of which have already been recorded and one, Mothocya epimerica which is new to the region. New hosts for Cerathotoa parallela and Nerocila orbignyi are reported. For each parasite species collected, the host fish, the parasitic specificity and the parasitological index are given.The study of the cymothoid isopod parasites on marine fishes from Tunisian localities has allowed us to distinguish eight species, seven of which have already been recorded and one, Mothocya epimerica which is new to the region. New hosts for Cerathotoa parallela and Nerocila orbignyi are reported. For each parasite species collected, the host fish, the parasitic specificity and the parasitological index are given.

Utilization of carotenoids from various sources by rainbow trout: muscle colour, carotenoid digestibility and retention

Rainbow trout (Oncorhynchus mykiss) with a mean (sd) weight of 120 (2) g were fed diets supplemented with astaxanthin extracted from the yeast Phaffia rhodozyma (OY1 = 50 mg carotenoids kg−1 feed, OY2 = 100 mg carotenoids kg−1 feed), astaxanthin (AX = 100 mg astaxanthin kg−1 feed) and canthaxanthin (CX = 100 mg canthaxanthin kg−1 feed) for 4 weeks. Muscle analyses at the end of the experiment indicated a significantly higher carotenoid concentration in the AX group, while CX and OY1 groups were similar in spite of the differences in dietary concentration. The measure of total muscle colour difference (ΔE*ab) between initial samples and 4 week ones was higher for the AX fish group but showed no significant difference between OY1, OY2, and CX. The hue and the reflectance ratio (R650:R510) of fish muscle increased in proportion to carotenoid intake. Digestibility (ADC) of yeast astaxanthin in OY1 and OY2 groups was significantly higher than that in the AX group. Canthaxanthin ADC was about one sixth of that of astaxanthin (AX group). Carotenoid retention in the muscle, expressed as a percentage of carotenoid intake, was higher for the AX group than that recorded for OY1 and OY2. According to ADC, carotenoid retention showed a marked lower value for the CX group. Muscle retentions were similar for astaxanthins from both sources.

The Effects of Dietary Astaxanthin on Growth and Moulting Cycle of Postlarval Stages of the Prawn, Penaeus japonicus (Crustacea, Decapoda)

Penaeus japonicus postlarvae reared in laboratory conditions were fed artificial diet either lacking of carotenoids (C) or supplemented with astaxanthin (A). Frozen Artemia was used as standard (S). The effects of dietary carotenoids on growth are relevant to the developmental stage of the animal as well as to the duration of the treatment. The protein content is not affected whatever the diet. Astaxanthin supplemented diet has been found to shorten the moulting cycle. Postlarvae fed pigmented diets (synthetic astaxanthin or canthaxanthin from Artemia) exhibit an ecdysteroid rate lower than that of the group receiving the control diet, extremely poor in carotenoids.

Nature and metabolism of carotenoid pigments during the embryogenesis of the European lobster Homarus gammarus (Linné, 1758)

Abstract The carotenoid concentration of the whole developing egg of the lobster Homarus gammarus remains unchanged during the embryogenesis. The decrease of pigment amounts in the vitellin mass corresponds to the transfer of carotenoids to the forming embryo. Esterified astaxanthin (mono and diester forms) appear during the early metanauplius stage EI 90. Unesterified astaxanthin is the main pigment occurring in the vitellus. Esterified forms were found to increase whereas free astaxanthin decreases up to hatch. The esterification of astaxanthin permits the storage of pigment in the tissues as an adaptative feature related to the formation of the embryo.

An annotated list of fish parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda, Nematoda) collected from Snappers and Bream (Lutjanidae, Nemipteridae, Caesionidae) in New Caledonia confirms high parasite biodiversity on coral reef fish

BackgroundCoral reefs are areas of maximum biodiversity, but the parasites of coral reef fishes, and especially their species richness, are not well known. Over an 8-year period, parasites were collected from 24 species of Lutjanidae, Nemipteridae and Caesionidae off New Caledonia, South Pacific.ResultsHost-parasite and parasite-host lists are provided, with a total of 207 host-parasite combinations and 58 parasite species identified at the species level, with 27 new host records. Results are presented for isopods, copepods, monogeneans, digeneans, cestodes and nematodes. When results are restricted to well-sampled reef fish species (sample size > 30), the number of host-parasite combinations is 20–25 per fish species, and the number of parasites identified at the species level is 9–13 per fish species. Lutjanids include reef-associated fish and deeper sea fish from the outer slopes of the coral reef: fish from both milieus were compared. Surprisingly, parasite biodiversity was higher in deeper sea fish than in reef fish (host-parasite combinations: 12.50 vs 10.13, number of species per fish 3.75 vs 3.00); however, we identified four biases which diminish the validity of this comparison. Finally, these results and previously published results allow us to propose a generalization of parasite biodiversity for four major families of reef-associated fishes (Lutjanidae, Nemipteridae, Serranidae and Lethrinidae): well-sampled fish have a mean of 20 host-parasite combinations per fish species, and the number of parasites identified at the species level is 10 per fish species.ConclusionsSince all precautions have been taken to minimize taxon numbers, it is safe to affirm than the number of fish parasites is at least ten times the number of fish species in coral reefs, for species of similar size or larger than the species in the four families studied; this is a major improvement to our estimate of biodiversity in coral reefs. Our results suggest that extinction of a coral reef fish species would eventually result in the coextinction of at least ten species of parasites.

Na+-K+ ATPase and carbonic anhydrase activities in larvae, postlarvae and adults of the shrimp Penaeus japonicus (Decapoda, Penaeidea)

Abstract 1. 1. Activities of Na + -K + ATPase and carbonic anhydrase were measured through the early post-embryonic development of Penaeusjaponicus . In adults, only the Na + -K + ATPase activity was measured. 2. 2. ATPase activity was variable in the successive development stages. From zero in nauplii, the activity slightly increased in zoeae, and rose sharply in mysis stages 2 and 3. 3. 3. A further significant increase in activity was noted at the transition from late mysis to early postlarvae, concomitant with a change from the larval osmoconforming pattern of osmoregulation to the postlarval and adult hyper-hyporegulating pattern. 4. 4. The activity of Na + -K + ATPase, measured in isolated cephalothorax, increased from PL3 to PL4 to its maximum value in PL5; at this stage, osmoregulatory capacity was fully efficient. 5. 5. In young stages of P. japonicus , the variations in Na + -K + ATPase activity appear correlated with the development of osmoregulatory ultrastructures, and with osmoregulation and salinity tolerance. 6. 6. These results are discussed with regard to their ecological and physiological implications. 7. 7. In adults, the activity of Na + -K + ATPase was high in gills and epipodites and no activity was detected in branchiostegites. These results are related to the ultrastructure of these organs. 8. 8. The activity of carbonic anhydrase did not change significantly in larval and postlarval stages. 9. 9. From these results, it is proposed that the effector sites of osmoregulation are located in branchiostegites, pleurae and epipodites in postlarvae, and in epipodites and mainly in gills in adults.