Maricultured organisms are chronically exposed to water containing antibiotics but the bioaccumulative behavior of antibiotics in exposed organisms at different growth stages has received little attention. Here, we investigated the concentrations and tissue-specific bioaccumulation characteristics of 19 antibiotics during three growth stages (youth stage, growth stage, and adult stage) of various organisms (Scophthalmus maximus, Penaeus vannamei, Penaeus japonicus, and Apostichopus japonicus) cultivated in typical marine aquaculture regions, and explored the factors that could affect the bioaccumulation of antibiotics. Tetracyclines (TCs) and fluoroquinolones (FQs) were the dominant antibiotics in all organisms, and the total concentrations of the target antibiotics in fish (S. maximus) were significantly higher than those in shrimp (P. vannamei and P. japonicus) and sea cucumber (A. japonicus) (p < 0.01). The bioaccumulation capacity of a class of statistically significant antibiotics in most samples was strongest during the youth stage and weakest during the adult stage. The antibiotics exhibited higher bioaccumulation capacity in lipid-rich tissues (fish liver and shrimp head) or respiratory organs (fish gill) than muscle. Our results also reveal significant metabolic transformation of enrofloxacin in fish. Different from previous studies, the logarithm bioaccumulation factor (log BAF) was positively correlated with log Dₗᵢₚw in low-biotransformation tissues (fish gill and muscle) rather than lipid-rich tissues (fish liver). Based on the calculated hazard quotients (HQ), doxycycline in fish muscle may pose a distinct risk to human health, which deserves special attention. Overall, these results provide insight into the bioaccumulation patterns of antibiotics during different growth stages and tissues of maricultured organisms.

Cadmium (Cd) pollution is currently the most serious type of heavy metal pollution throughout the world. Previous studies have shown that Cd elevates the mortality of paddy field spiders, but the lethal mechanism remains to be explored profoundly. In the present study, we measured the activities of protective enzymes (acetylcholinesterase, glutathione peroxidase, phenol oxidase) and a heavy metal chelating protein (metallothionein) in the pond wolf spider Pardosa pseudoannulata after Cd exposure. The results indicated that Cd initially increased the enzyme activities and protein concentration of the spider after 10- and 20-day exposure before inhibiting them at 30-day exposure. Further analysis showed that the enzyme activities in the cephalothorax were inhibited to some extent. Since the cephalothorax region contains important venom glands, we performed transcriptome sequencing (RNA-seq) analysis of the venom glands collected from the spiders after long-term Cd exposure. RNA-seq yielded a total of 2826 differentially expressed genes (DEGs), and most of the DEGs were annotated into the process of protein synthesis, processing and degradation. Furthermore, a mass of genes involved in protein recognition and endoplasmic reticulum (ER) -associated protein degradation were down-regulated. The reduction of protease activities supports the view that protein synthesis and degradation in organelles and cytoplasm were dramatically inhibited. Collectively, our outcomes illustrate that Cd poses adverse effects on the expression of protective enzymes and protein, which potentially down-regulates the immune function in the venom glands of the spiders via the alteration of protein processing and degradation in the ER.

The effects of microplastic fibers (MPF) on the survival, molting and oxygen consumption rates of larval (I-III) and post-larval (IV) stages of the American lobster, Homarus americanus, were quantified as a function of MPF concentration and food availability. Only the highest MPF concentration decreased early larval survival. MPF did not affect the timing or rate of molting across MPF treatments. While all larval and post-larval stages accumulated MPF under the cephalothorax carapace, stage II larvae and stage IV post-larvae showed the highest and lowest accumulation, respectively. MPF ingestion increased with larval stage and with MPF concentration; under starvation conditions, stage I larvae only ingested them at low MPF concentrations. Oxygen consumption rates were lower only in later larval stages when exposed to high MPF concentrations. Combined, our results indicate that MPF interactions and effects on American lobster larvae are dependent on larval stage, MPF concentration, and presence of food.

Uptake and depuration kinetics of dissolved [14C]C12-6-linear alkylbenzene sulfonate (LAS) were determined in the shrimp Palaemonetes varians using environmentally relevant exposure concentration. The shrimp concentrated LAS from seawater with a mean BCF value of 120Lkg−1 after a 7-day exposure. Uptake biokinetics were best described by a saturation model, with an estimated BCFss, of 159±34Lkg−1, reached after 11.5days. Shrimp weight influenced significantly BCF value with smaller individuals presenting higher affinity to LAS. To the light of a whole body autoradiography, major accumulation of LAS occurred in the cephalothorax circulatory system (gills, heart, hepatopancreas) and ocular peduncle, but not in the flesh, limiting potential transfer to human consumers. LAS depuration rate constant value of the shrimp was 1.18±0.08d−1 leading to less than 1% of remaining LAS in its tissues after 8days of depuration.

The giant freshwater prawn, Macrobrachium rosenbergii, is an important species for Bangladesh’s national economy, aquatic biodiversity, and employment opportunities; furthermore, human health risk associated to consumption of this species has become a crucial issue. Eight trace metals (Pb, Cr, Ni, Cd, Fe, Cu, Zn, and Mn) in different body parts of M. rosenbergii (U/10 as large and U/12 and U/15 as medium size), and water collected from farm and wild sources along with the human health risks were assessed in this study. Except Cd, all trace metals exceeded the maximum permissible limits proposed by different authorities. Elevated levels of Pb, Cr, Fe, Cu, Zn, and Mn were found in the wild-caught prawn, whereas Ni and Cd were higher in farmed prawn. A higher trace metal contamination was recorded from the cephalothorax part than the abdomen of both sized prawns. However, trace metal concentrations between two sizes of prawns were not statistically significant (p > 0.05). The estimated daily intakes (EDI) values were higher than the recommended and/or tolerable daily intake for Pb and Cr. Moreover, the target hazard quotient (THQ) values were > 1 for Pb, Cd, Cu, and Zn, elucidating non-carcinogenic risks to the consumers. In addition, the target cancer risk (TR) values of Pb and Ni were high and exceeded the acceptable guideline of 10⁻⁶, explicating the possibility of carcinogenic risks. Therefore, the study concludes that the consumption of the studied prawn species contaminated with elevated levels of toxic metals is associated with higher degree of potential health risks.

Freshwater crayfish are bioindicators of environmental pollution, often used for the assessment of heavy metal (HM) presence in the tissues, a time-consuming and expensive task. In this study, we propose the use of the vibrational spectroscopy to detect in a fast, non-destructive and sensitive way the presence of HM in the cephalothorax exoskeleton of the freshwater crayfish. Incorporation of HM into the cephalothorax exoskeleton was investigated under controlled laboratory conditions. In particular, the cephalothorax exoskeleton of five crayfish species (Astacus leptodactylus, Procambarus clarkii, Austropotamobius pallipes, Faxonius limosus, and Pacifastacus leniusculus) was analyzed by attenuated total reflection–Fourier transformed infrared (ATR–FTIR) spectroscopy in the presence or absence of cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni), and zinc (Zn) up to 4 weeks at various concentrations (0.01, 0.1, 1, 10, ppm). The ATR–FTIR profile of the crayfish cephalothorax exoskeleton was compatible with the presence of amorphous calcium carbonate, chitin, and proteins. The incubation with the HM revealed two main modifications: the shift of the peak from 859 to 872 cm⁻¹ and the appearance of a peak at 712 cm⁻¹. Both are ascribable to the HM interaction with calcium carbonate. The absorbance of both peaks increased along with the time of incubation, and the HM concentration. We conclude that ATR–FTIR analysis can be a useful, quick, and cost-sensitive tool to detect HM presence in the crayfish cephalothorax exoskeleton. However, it has to be regarded as a non-specific analytical technique for assessing HM contamination, since it is unable to discriminate between different HM.

Since the end of the 1980s, white shrimps (Palaemon longirostris) from the Gironde estuary have exhibited exoskeletal malformations, mainly involving cephalothorax, rostrum, scaphocerites and uropods. An 8-month study was carried out in 2015. Each month, 200 individuals were sampled and examined for exoskeletal malformations. Temporal variations in malformation frequency were noted, particularly during the breeding period, along with decreases in the size of non-deformed shrimps related to the appearance of juveniles in breeding sites, and high mortality among deformed shrimps. A significant increase in proportions of deformed shrimp was observed, relating particularly to the size (and therefore the age) of individuals. No significant difference was found between shrimp proportions with different numbers of malformations (one to four) for a fixed size class, nor was there any variation in proportions within different size classes for a fixed number of malformations. This would appear to indicate that the number of malformations is acquired and new malformations do not seem to appear during the life cycle, except for the smallest (youngest) shrimps. The malformation spectrum showed no significant differences between the biggest and smallest individuals for the different malformation associations, except for those involving cephalothorax, rostrum and uropods. This would suggest that some malformation associations lead to a higher mortality rate in shrimps subjected to them, due to greater impairment of feeding and/or swimming behaviour. Multiple component analysis of the different types of malformation showed correlations between exoskeletal pieces (rostrum and cephalothorax) and appendixes (scaphocerites and uropods). Regarding metal contamination in shrimp, no significant difference was highlighted between deformed and non-deformed shrimps. Organic pollutants were not measured in tissues. Certain herbicides such as metolachlore and chlortoluron were detected at high concentrations in the Gironde estuary during the breeding period corresponding to the higher occurrence of exoskeletal malformations.