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The hypothesis of this work was that oxidative and nitrosative metabolism in the digestive gland (DG) of two limpet populations (intertidal and subtidal) of the Antarctic species Nacella concinna show different behavior when they were exposed to either intermittent (intertidal) or constant (subtidal) natural Fe. Total Fe content and labile Fe pool were higher in the DG of the subtidal compared to the intertidal population. However, no significant differences between populations were seen on the Fe atoms content of the isolated ferritin. Ascorbyl radical content was 2.0 ± 0.4 and 6.5 ± 0.8 pmol/mg FW in the DG of the intertidal and subtidal animals, respectively. Lipid damage, assessed as content of thiobarbituric reactive substances, was different between the tissues of intertidal and subtidal samples, 491 ± 102 and 1242 ± 367 pmol/mg FW, respectively. Catalase and superoxide dismutase activities showed no differences between the limpets. Nitric oxide (NO) content was 25 ± 3 and 22 ± 2 pmol/mg FW in DG from intertidal and subtidal animals, respectively. NO synthase-like (NOS-like) activity was evaluated supplementing the samples with the enzyme co-factors, and the inhibitory effect of Nω-nitro-L-arginine methyl ester hydrochloride was tested. NO generation rate was 3.4 ± 0.3 and 4.7 ± 0.6 pmol/min mg FW in DG from the intertidal and subtidal population, respectively. These results showed that the oxidative condition of the limpet population constantly covered by the Fe enriched water is more affected than the intertidal population. However, the nitrosative metabolism seems to be independent of the environmental high Fe content since similar NO steady state concentration and NOS-like activity were measured in both populations. [ABSTRACT FROM AUTHOR]

The hypothesis presented here is that oxidative and/or nitrosative metabolism in the bivalve Mytilus edulis platensis is altered by the presence of planktonic toxins. Digestive glands (DG) were isolated from specimens collected in the Argentinean Sea during summer, winter and spring (in the presence of harmful planktonic toxins). The labile iron pool content was not significantly different in DG from animals collected in summer and winter, but was 2.3-fold increased in samples from spring compared to summer collected mollusks. The 2′,7′ dichlorofluorescein diacetate (DCFH-DA) oxidation, ascorbyl radical/ascorbate and lipid radical/α-tocopherol content ratios showed no significant differences between samples collected in winter and summer. However, spring collected samples showed significantly higher DCFH-DA oxidation rate and oxidative ratios in comparison to DG from mollusks collected in summer. Superoxide dismutase activity decreased by 75% in winter, and 93% in spring, compared to samples collected in summer. Glutathione S-transferase activity decreased by 89% in winter, and 30% in spring, compared to samples collected in summer. Catalase activity in winter animals increased by 3.8-fold in comparison to summer values, with no differences between spring and summer collected mollusks. Nitrite plus nitrate content was not significantly different among samples collected in the three seasons, but nitric oxide content was 8.5- and 2.7-fold higher in samples from winter and spring collected mollusks than values obtained in summer, respectively. These results showed the lack of effects of climatic changes on the integrative oxidative indexes; however, under exposure to toxins, both oxidative and nitrosative metabolisms were affected. [ABSTRACT FROM AUTHOR]

Bivalve mollusks bioaccumulate toxins via ingestion of toxic dinoflagellates. In this study, Crassostrea gigas was used to investigate the effects related to Prorocentrum lima exposure. Oysters were fed with three diets Isochrysis galbana (2 × 10 6 cell mL −1 ) control treatment; algal mix of I. galbana (2 × 10 6 ) and P. lima (3 × 10 3 cell mL −1 ); and P. lima alone (3 × 10 3 cell mL −1 ). Feeding behavior changes, histopathological alterations, and expression patterns changes of genes involved in cell cycle ( p21, cafp55, p53 ), cytoskeleton ( tub , act ), and inflammatory process ( casp1 ) were evaluated. Results indicated that the presence of diarrheic shellfish poisoning by P. lima cells decreased the clearance rate ( p < 0.05), induced structural loss, significantly decreased tubule area of the digestive gland ( p < 0.05), and up-regulated in expression all gene ( p < 0.05), suggesting that toxic cells might trigger inflammatory tissue process, disturb cell cycle and cytoskeleton representing a risk to oysters integrity. [ABSTRACT FROM AUTHOR]

Food limitation is a common challenge for animals. Cephalopods are sensitive to starvation because of high metabolic rates and growth rates related to their 'live fast, die young' life history. We investigated how enzymatic capacities of key metabolic pathways are modulated during starvation in the common cuttlefish ( Sepia officinalis) to gain insight into the metabolic organization of cephalopods and their strategies for coping with food limitation. In particular, lipids have traditionally been considered unimportant fuels in cephalopods, yet, puzzlingly, many species (including cuttlefish) mobilize the lipid stores in their digestive gland during starvation. Using a comprehensive multi-tissue assay of enzymatic capacities for energy metabolism, we show that, during long-term starvation (12 days), glycolytic capacity for glucose use is decreased in cuttlefish tissues, while capacities for use of lipid-based fuels (fatty acids and ketone bodies) and amino acid fuels are retained or increased. Specifically, the capacity to use the ketone body acetoacetate as fuel is widespread across tissues and gill has a previously unrecognized capacity for fatty acid catabolism, albeit at low rates. The capacity for de novo glucose synthesis (gluconeogenesis), important for glucose homeostasis, likely is restricted to the digestive gland, contrary to previous reports of widespread gluconeogenesis among cephalopod tissues. Short-term starvation (3-5 days) had few effects on enzymatic capacities. Similar to vertebrates, lipid-based fuels, putatively mobilized from fat stores in the digestive gland, appear to be important energy sources for cephalopods, especially during starvation when glycolytic capacity is decreased perhaps to conserve available glucose. [ABSTRACT FROM AUTHOR]

One of the bottlenecks in cultivating juvenile green abalone Haliotis fulgens is the lack of well-adapted natural or formulated food for optimal growth. The goal of this study was to analyse the digestive gland structure of juvenile green abalone fed rehydrated natural feed, Ulva sp. (Chlorophyta), Eisenia arborea, Macrocystis pyrifera, Egregia menziesii (Phaeophyta) and Porphyra perforata (Rhodophyta), using histochemical techniques. Structure of the digestive gland was described, and proteoglycan granules were detected in the digestive cells. The abundance of granules was variable, depending on the feed provided to the abalone, and this was reflected in their growth. Granular content in digestive cells fed Ulva sp. was scarce, leading to low growth rate and high feed conversion ratio (FCR). Digestive cells of juveniles fed E. menziesii led to the best nutritional condition, including many proteoglycans cellular granules, best weight growth rate and a low FCR. Histochemical analysis of the digestive gland, differentiated by a modified Goldner trichrome method that included Alcian blue, was a useful tool for determining the nutritional status of farmed abalone, therefore recommended for assessing adjustments to the natural feed or formulation to meet the nutritional needs of abalone. [ABSTRACT FROM AUTHOR]

To determine the metabolic response to food deprivation, cuttlefish (Sepia officinalis) juveniles were either fed, fasted (3 to 5 days food deprivation), or starved (12 days food deprivation). Fasting resulted in a decrease in triglyceride levels in the digestive gland, and after 12 days, these lipid reserves were essentially depleted. Oxygen consumption was decreased to 53% and NH4excretion to 36% of the fed group following 3-5 days of food deprivation. Oxygen consumption remained low in the starved group, but NH4 excretion returned to the level recorded for fed animals during starvation. The fractional rate of protein synthesis of fasting animals decreased to 25% in both mantle and gill compared with fed animals and remained low in the mantle with the onset of starvation. In gill, however, protein synthesis rate increased to a level that was 45% of the fed group during starvation. In mantle, starvation led to an increase in cathepsin A-, B-, H-, and L-like enzyme activity and a 2.3-fold increase in polyubiquitin mRNA that suggested an increase in ubiquitin-proteasome activity. In gill, there was a transient increase in the polyubiquitin transcript levels in the transition from fed through fasted to the starved state and cathepsin A-, B-, H-, and L-like activity was lower in starved compared with fed animals. The response in gill appears more complex, as they better maintain rates of protein synthesis and show no evidence of enhanced protein breakdown through recognized catabolic processes. [ABSTRACT FROM AUTHOR]

Histochemical techniques today allow you to select areas of tissue and generate reliable information on the distribution of energy reserves in bivalve molluscs during their life cycle. The main objective of this study was to describe and relate the gametogenic cycle with the availability of energy reserves and the environmental parameters. For this, we sampled and examined the gonads and digestive glands (DG) of 15 individuals collected monthly during April 2012 and February 2013. We processed and analyzed the samples by standard histological and histochemical light microscopy techniques. Our results showed that for the gametogenic cycle, the monthly proportion of mature organisms was higher for males, between August (40%) and November (53%), while the females tend to have a shorter synchronized cycle and release of gametes in September (67%) and October (60%). The intense spawning periods in both sexes was the same (October to January). Between the periods April-August 2012 and January-February 2013, we observed the highest values of IGl and glucide index (instead, a decrease was observed in September, reaching minimum values during the period October-December). Besides, the maximum values of IL, lipid index, were observed in April-2012 and February-2013, with an intermediate value in August-2013. The results indicated that the reserves of the GD have a pattern of mobilization inversely related to the proliferation of gametes in both sexes; this was directly linked to the availability of nutrients such as chlorophyll a and the organic seston. [ABSTRACT FROM AUTHOR]

The histological organization and ploidy levels of the digestive gland cells in 34 species of prosobranch gastropod mollusks that belong to the subclasses Patellogastropoda, Vetigastropoda, and Caenogastropoda (orders Littorinimorpha and Neogastropoda) were investigated using histochemical methods and cytophotometry of nuclear DNA. Two general types of differentiated cells, viz., digestive and basophilic (secretory-calcium), were identified in the epithelium of the digestive tubules. In Vetigastropoda and Neogastropoda species, all the cells are mostly diploid. In representatives of Patellogastropoda and Littorinimorpha, the digestive cells are diploid as well, but basophilic cells of many species reach polyploidy levels of 4-8 c and in some species, even 4-8-16 c. Cases of somatic polyploidy in basophilic cells are considered as adaptive modifications of histogenesis associated with the peculiarities of the environment (intensified metabolism in osmotically tolerant Littorina and Lottia species), the duration of ontogenesis (the short life cycle in Lacunida species), and a specific diet. [ABSTRACT FROM AUTHOR]

Concentrations of the paralytic shellfish toxins C1+2, C3+4, GTX5, GTX6, dcGTX2+3, dcSTX, dcNEO, GTX2+3, GTX1+4, STX and NEO were determined by LC-FLD in composite samples of digestive glands and gills of Cerastoderma edule cockle. The specimens were sampled in Aveiro lagoon, Portugal, under natural depuration conditions (days 0, 8, 12, 14, 19, 21 and 25) after exposure to a bloom of Gymnodinium catenatum . Individual paralytic shellfish toxins indicated different pathways of elimination and biotransformation in digestive gland and gills. Toxin concentrations in gills were lower than in digestive gland. Most of the quantified toxins in digestive gland decreased during the 25 days of observation according to negative exponential curves, and only GTX5, GTX6 and NEO showed slight irregularities with time. Concentrations of C1+2, C3+4 and dcGTX2+3 in gills decreased progressively, however GTX5, GTX6 and dcSTX showed pronounced increases. Higher concentrations of those toxins in days 8 and 12 in comparison to the initial value (day 0) indicate conversion of other toxins into GTX5, GTX6 and dcSTX during those periods. It appears that inter-conversion of toxins occurs as G . catenatum cells are retained in gills before being transferred to other compartments. [ABSTRACT FROM AUTHOR]

Objective To research the expression of homocysteine induced gene (HCY-2) in the main organs of esophagus, stomach, small intestine and liver during the human embryonic digestive system development and its role in digestive system development. Methods The different periods of normal developmental human embryonic esophagus, stomach, small intestine and liver were collected and the HCY-2 expression in these organs was semi-quantitatively analyzed by adopting the immunohistochemical avidin-biodin-peroxidase compound method and image analysis technique. Results HCY-2 was expressed during the whole development process of human embryonic esophagus, stomach, small intestine and liver. Different pregnant stages had different expression intensities. The expression protein was mainly distributed in the mucosal epithelial cells of digestive tube and hepatocytes, moreover in the cytoplasm. The expression of HCY-2 in esophageal mucosal epithelial cells was strongest in middle stage of pregnancy and weakest in the early stage of pregnancy;the expression of HCY-2 in the stomach mucosal epithelial cells was strongest near full term and weakest in the middle stage of pregnancy; the expression of HCY-2 in small intestine mucosal epithelial cells and liver cells was attenuated gradually following embryo developing,which was strongest in the early pregnancy and weakest near full term. Conclusion HCY-2 could participate in the development of human embryonic digestive tube and digestive glands. [ABSTRACT FROM AUTHOR]

A crystallization method was developed to enhance the purity and stability of hydrolase mixtures from the digestive gland of the snail Achatina fulica , as demonstrated by chitinase activity. Crude chitinase was concentrated by freeze drying and then crystallized at 10 °C. Crystal formation was observed under the microscope. The best concentration for crystallization was obtained with 1.5-fold concentrated crude chitinase. Crystallization enhanced the chitinase specific activity from 0.87 U mg -1 to 0.95 U mg -1 . The loss of chitinase activity from liquid and crystals of crude chitinase on four days storage at 10 °C was 83.0% and 17.7%, respectively. It was concluded that the crude chitinase crystals showed a significant increase in stability and purity. [ABSTRACT FROM AUTHOR]

The decrease of ice cover in the Arctic will lead to an increase of ship traffic in the upcoming decades. Consequently, oil pollution is expected. In this context, the goals of this study were to evaluate the biological impact of marine diesel contamination and, on this basis, to determine analytical tools of interest (biomarkers) for future biomonitoring of diesel spills. Using a 7-day contamination protocol, this study investigated biochemical modulations in the digestive gland of the Iceland scallop ( Chlamys islandica). Incorporation of contaminants was verified assessing haemolymph metabolites. Results showed a response of glutathione-S-transferase to contamination suggesting detoxification processes and the suitability of such a tool for diesel spill biomonitoring. The lack of modulation of superoxide dismutase activity and lipid peroxidation suggests no oxidative stress and the unsuitability of these molecular tools for biomonitoring. [ABSTRACT FROM AUTHOR]

The comet assay was used to study the sensitivity of the widely distributed freshwater bivalve mollusk Corbicula fluminea to the DNA-damaging alkylating-agent methylmethane sulfonate (MMS). This study was undertaken to ascertain if C. fluminea is a good bioindicator of pollutants in aquatic environments and identify which C. fluminea tissue is most effective and practical for genotoxicity studies. The mollusks were exposed to 0.6, 1.2 or 2.4 X 10-4 M MMS for 40 min and their hemolymph, gill tissue and digestive gland tissue assessed for the level of DNA damage and the time needed for the tissues to recovery. Regression analysis showed a direct linear dose-response relationship between MMS concentration and the number of damaged cells for hemolymph and digestive gland tissue but a quadratic relationship for gill tissue, which made the interpretation the gill tissue results difficult. The basal level of DNA damage to gill tissue was very high, possibly because gill is the organs most directly exposed to environmental toxins and mutagenic agents. Although all three types of tissue produced useful results, hemolymph and digestive gland tissue produced more reproducible and reliable results. Hemolymph was the best sample type in that it was easy to obtain and handle, while gill tissue required more manipulation to obtain cell suspensions. Our results indicate that C. fluminea is an optimal bioindicator for the determination genotoxic contaminants in aquatic environments.

Electrophoretical and histological analysis were performed on Mytilus galloprovincialis digestivegland samples, in order to detect the presence of a previously identified protein ca 30 kDa MW,synthesized during Dinophysis spp. blooms, and assess a possible correlation between the occurrenceof this protein and okadaic acid (OA) exposure by ingestion. Mussels were sampled monthly from July2000 to November 2001 in the Gulf of Trieste (upper Adriatic Sea) and immediately processed. Parallelsamples were maintained in sea water plastic tanks and fed with marine invertebrate feed mixed withOA and derivatives at different concentration of toxins for each experimental group (25 mg, 50 mg, 100mg). In tank reared mussels fed with OA, degeneration of digestive cells and appearance of 24.6 kDaprotein were observed, while in wild mussels, neither histological alterations nor presence of a 24.6kDa protein, were detected. A correlation between the toxins concentration and time of appearancewas highlighted, to demonstrate this protein is synthesized in response to OA and derivativesexposure. About the identity of 24.6 kDa protein, it could be an enzyme involved in detoxificationreactions, probably Glyoxalase I.

This study evaluated the combined effects of seawater pH decrease and temperature increase on the activity of antioxidant enzymes in the thick shell mussel Mytilus coruscus , an ecological and economic bivalve species widely distributed along the East China Sea. Mussels were exposed to three pH levels (8.1, 7.7 and 7.3) and two temperatures (25 °C and 30 °C) for 14 days. Activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione (GSH), acid phosphatase (ACP), alkaline phosphatase (AKP) and glutamic-pyruvic transaminase (GPT) were measured in gills and digestive glands after 1, 3, 7 and 14 days of exposure. All enzymatic activities were significantly impacted by pH, temperature. Enzymatic activities at the high temperature were significantly higher than those at the low temperature, and the mussels exposed to pH 7.3 showed significantly higher activities than those under higher pH condition for all enzymes except ACP. There was no interaction between temperature and pH in two third of the measured activities suggesting similar mode of action for both drivers. Interaction was only consistently significant for GPX. PCA revealed positive relationships between the measured biochemical indicators in both gills and digestive glands. Overall, our results suggest that decreased pH and increased temperature induce a similar anti-oxidative response in the thick shell mussel. [ABSTRACT FROM AUTHOR]

The present study was conducted to elucidate the effects of copper exposure on the immune system and lipid metabolism of the Japanese scallop, Mizuhopecten yessoensis . Transcriptional levels of differentially expressed genes (DEGs)in M. yessoensis digestive gland tissue were analyzed using the deep-sequencing platform Illumina HiSeq™ 2000. In total, 841 and 877 genes were identified as significantly up- or down-regulated, respectively. In addition, significant enrichment analysis identified 3 gene ontology terms and 15 pathways involved in the response to copper exposure. Analysis of transcripts related to the immune response revealed a complex pattern of innate recognition receptors, including toll-like receptors, NOD-like receptors and downstream pathway effectors, including those involved in apoptosis. Furthermore, genomic analysis revealed that genes involved in extracellular matrix (ECM)-receptor interactions were enriched in Cu-exposed scallop glands. These results will provide a resource for subsequent gene expression studies regarding heavy metal exposure and the identification of copper-sensitive biomarkers for the aquaculture of M. yessoensis . [ABSTRACT FROM AUTHOR]

Reports indicating the presence of pharmaceutical in fresh water environment in the ng L −1 to µg L −1 range are occurring with increasing frequency. It is also a fact that pharmaceuticals may produce adverse effects on aquatic organisms. Nevertheless, there is still a lack of knowledge regarding how these emergent contaminants may affect aquatic biota. The goal of this research was to evaluate the sublethal responses in Corbicula fluminea such as, general stress (lysosomal membrane stability [LMS]), biomarkers of phase I and II (etoxyresorufin O-deethylase [EROD], dibenzylfluorescein dealkylase [DBF], gluthathione-S-transferase [GST]), oxidative stress (gluthathione reductase [GR], gluthathione peroxidase [GPX], lipid peroxidation [LPO]), and biomarkers of effect (DNA damage) after 21 days of exposure to caffeine, ibuprofen, carbamazepine, novobiocin and tamoxifen at 0.1, 1, 5, 10, 15, 50 µg L −1 . Environmental concentrations tested in this study caused general stress and produced changes on biomarkers tested. LMS, responses from phase I and II enzymatic activity, oxidative stress, and biomarker of effect represent important ecotoxicological information, and will provide a useful reference for the assessment of selected drugs and the effects which these compounds may have on aquatic invertebrates, using C. fluminea as a bioindicator species. [ABSTRACT FROM AUTHOR]

In view of the importance of Mytilus species in marine ecology and environmental quality assessment, all aspects of mussel enzymes that are related to environmental factors are of great relevance. A lysosomal enzyme, deoxyribonuclease II, a member of the acid deoxyribonucleases, has a major role in cellular DNA degradation. The presence and seasonal variations of the acid deoxyribonuclease (DNase) activity in the digestive gland and gills of the mussel Mytilus galloprovincialis were investigated. The enzyme was localized in the lysosomal vacuolar system of both gill and digestive gland tissues. Two active acid DNase isoforms were detected in the digestive gland (48 and 37 kDa) and one in the gills (48 kDa). All active enzyme isoforms coincided with protein bands immunoreactive to antibodies raised against human DNase II. Post-translational lysosomal processing of acid DNase in the digestive gland but not in the gills indicated tissue-specific enzyme maturation. The activity of acid DNase determined across the annual cycle showed a tissue-specific pattern that could be related to the seasonal activity of mussel organs and their biological function. In the digestive gland, high DNase activity was observed in relation to food availability and spawning. Higher enzyme activity in the gills observed in the autumn/winter period could be associated with feeding and cellular adaptation to low seawater temperatures. [ABSTRACT FROM AUTHOR]

Metallothionein (MT) is established as a potentially useful biomarker for monitoring aquatic pollution. This paper addresses widespread inconsistencies in storage conditions, tissue type selection and pre-treatment of samples before MT and metal analysis in biomarker studies. This variation hampers comparability and so the widespread implementation of this monitoring approach. Actively sampled Mytilus edulis in Southampton Water, UK were exposed to different storage temperatures, a variety of tissue types were analysed, and various pre-treatments of transportation on ice, transportation in seawater, depuration, and rapid dissection in the field were examined. Storage temperatures of − 20 °C were found to be adequate for periods of at least ten weeks, as MT was not reduced by protein degradation compared with samples kept at − 80 °C. Whole tissue and digestive gland concentrations of MT and metals were significantly positively correlated and directly relatable. MT in the digestive gland appeared to be more responsive to metals than in whole tissue, where it may be diluted, masking MT responses. However, longer study periods may suffer the effects of mass changes to the digestive gland, which alters MT concentration, and it may therefore be advisable to measure whole tissue. Depuration and transportation in seawater reduced both MT and metal concentrations in the digestive gland, and few correlations between MT and metals were identified for these treatments. It is therefore recommended that: i) samples are transported to the laboratory on ice and dissected as soon as possible thereafter, ii) depuration should not be used when examining MT response to metal exposure until further research clarifying its utility is reported, iii) either whole tissue or the digestive gland can be used to measure MT, though whole tissue may be preferable on long-term studies, and iv) organisms can be stored at − 20 °C before analysis for up to ten weeks. These practices can be applied to future biomonitoring studies and will improve the comparability and repeatability of using MT as a biomarker. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate heavy metals (Cr, Fe, Ni, Cu, Zn, As, Cd, Hg, Pb) and selenium levels in digestive gland and gill tissues of wild Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819) collected from four locations in Izmir Bay. Methods: A total of 180 samples of the wild Mediterranean mussel M. galloprovincialis with shell length of 50-60 mm were collected from four locations. Inductively coupled plasmamass spectroscopy was used to determine heavy metals and selenium concentrations in mussel samples after microwave digestion process. Results: The highest values (mg kg-1 dry weight) obtained for digestive gland and gills were 0.17 and 0.15 for Cr, 28.62 and 29.49 for Fe, 0.25 and 0.29 for Ni, 2.53 and 1.78 for Cu, 18.52 and 22.03 for Zn, 1.26 and 1.08 for As, 0.04 and 0.04 for Cd, 0.02 and 0.02 for Hg, 0.19 and 0.16 for Pb, 0.40 and 0.48 for Se, respectively. Statistically significant differences among digestive gland and gills (p<0.05) were found for Cr, Ni, Zn, As, Se and Cd. In general, the levels of the studied elements were higher for the Karşıyaka than for other three stations. Conclusion: The low levels of toxic metals (Cd, Hg, Pb, Cr, Ni) found in tissues of M. galloprovincialis, comparing with the other studies including taken place in the Inner of Izmir Bay. M. galloprovincialis can be used as a sensitive biomonitor for the availabilities of studied elements in the Inner Bay of Izmir, Turkey. [ABSTRACT FROM AUTHOR]

Most nutritional studies on Octopus vulgaris were based on males to avoid interaction with reproductive processes, focusing on muscle and digestive gland tissues. This study intends to evaluate the effect of two fresh diets, a fish diet (bogue Boops boops) and a mixed diet (600 g kg−1 crab Portunus pelagicus and 400 g kg−1 bogue), on the biochemical composition of muscle, digestive gland and gonad in males and females of O. vulgaris. Six octopuses per diet were selected ( n = 3 per sex) after 60 days of rearing in floating cages. Weight increase was higher in males (3-3.2 kg) than in females (0.9 kg) regardless of diet associated with sexual maturation. Gondosomatic Index in females was 11.3-13.4%. High-lipid content in fish (440 g kg−1 dw) was reflected in digestive gland regardless of the diet, while muscle and testis showed a relatively stable composition. The increase in protein content in the ovary was related to sexual maturation. The low arachidonic content in bogue was reflected in all tissues, with no apparent negative effect on growth and welfare. However, specific retention of arachidonic in the gonads, related to high arachidonic content in crab, underlined the importance of this fatty acid in for gonad development in O. vulgaris. [ABSTRACT FROM AUTHOR]

This study deals with the structure of the digestive gland of the carnivorous gastropod Adelomelon beckii in Mar del Plata area (Argentina) and discusses the function of its cell types and compare with other gastropods. According to histological and transmission electron microscopy observations the epithelium is composed of two types of cells that are subject to cyclical changes, involving three phases: absorption, digestion and fragmentation. The majority of the cells, called digestive cells, have a basal nucleus with a cytoplasm filled by spherical digestive vesicles in different stages. The apical pole of the cell is covered with microvilli and cilia and shows evidence of endocytotic activity during the absorption phase. The intracellular digestive process passes through: (1) fusion of endocytotic vesicles; (2) transformation in heterolysososmes by fusion with enzyme-rich vesicles; (3) formation of residual bodies after digestion, which are pinched off to the lumen gland during fragmentation phase. The second type of cell in the acini are called vacuolated cells, which occur in clusters, the nucleus is in the mid-basal region and the cytoplasm is basophilic, filled with stacks of RER. During the absorption phase the vacuolated cells secrete neutral mucins that probably serve as lubrication to facilitate transport of food particles. During all phases, a large amount of lipofuscin, an insoluble pigment that is accumulated after lysosome digestion, is accumulated. The functional morphology of the different cell types found in this carnivorous gastropod is very similar to that found in herbivorous and deposit-feeding gastropods, which suggests that the feeding type does not influence the micro-morphology of the digestive gland. [ABSTRACT FROM AUTHOR]

In cephalopod hatchlings there is a transitional period considered critical, in which the digestive system undergoes morphophysiological changes associated with the passage from the consumption of vitelline reserves to an independent feeding. During this period, the characterization of the digestive dynamics and growth is key information to define their nutritional requirements under culture. Octopus tehuelchus , which has become increasingly interesting for cultivation, is a species endemic to South America with holobenthic development and large juveniles. In this work, the enzymatic and cytological changes of the digestive gland (DG) along with the variation in body weight and size of O. tehuelchus hatchlings were evaluated when reared at 16 °C under two feeding treatments: fed with the isopod Exosphaeroma sp. and starved. In fed juveniles, the predatory activity began a few hours after hatching; and up to 6 days post hatching (DPH) there was neither somatic growth nor cellular differentiation of the DG, but there was an activation of acid enzymes. From 6 to 10 DPH, there was an increase in the size and weight of juveniles, and the maturation of the DG began with the appearance of heterolysosomes and heterophagosomes. Furthermore, lipases activity reached its maximum level and there was a considerable increase in both alkaline phosphatases and peptidases. From 15 to 25 DPH, the DG became fully mature and the lipase activity reached minimum levels, while the alkaline peptidases continued increasing. At the end of the experiment, at 25 DPH, fed juveniles doubled their weight. In the starved juveniles, neither somatic growth nor cytological differentiations of the DG were registered. Besides, in this treatment, acid phosphatases and lipase activities (i.e. enzymes related to yolk consumption) remained at basal levels or decreased over time, even with yolk platelets still present, suggesting that the consumption of yolk reserves would be delayed, regulating the survival time. In fed juveniles, the ingestion of isopods seems to act as a modulating factor of the digestive activity, triggering an increment in the activity of lipases, acid phosphatases, as well as alkaline peptidases which are related to the digestion of exogenous food. It is concluded that morphological and physiological changes during the digestive maturation are related to the ingestion of Exosphaeroma sp. In this sense, this isopod species would be a suitable food which promotes the rapid growth of O. tehuelchus during their early post-hatching stage under culture. • The consumption of yolk reserves is regulated according to the availability of food. • A feeding based on Exosphaeroma sp. has a positive effect on growth of Octopus tehuelchus juveniles. • Growth and digestive gland differentiation are seen from the second week of life in fed hatchlings. • The energy available from yolk is used for maintenance and not for development in non-fed juveniles. [ABSTRACT FROM AUTHOR]

The freshwater gastropod Bellamya bengalensis exposed to 69.18ppm concentration of detergent (Tide) on lipid content in the tissue of foot, mantle and digestive glands for 96 hours exposure. Compare to control group there was significant change in lipid contents from foot, mantle and digestive glands in detergent exposed groups. Total lipids in the digestive gland increased after 96 hrs of exposure to detergent (Tide). The percent change in lipid level is +13.87. But in case of foot and mantle, decrease of lipids was observed at 96 hrs exposure. This may be due to increased lipid synthesis or probably to facilitate transfer of materials from the storage organ to other parts of the body.