Digestive Tract Contents Research Articles

Limited uptake of [14C]Gardenia Blue administered orally in male and female rats and mice.

Gardenia blue (GB), a widely used plant-derived food color is prepared by reaction of genipin, the aglycone of geniposide, with protein hydrolysate. Recent animal studies investigating GB toxicity have indicated blue coloration in the gastrointestinal tract, kidneys and mesenteric lymph nodes in rodents following dietary administration. This study investigated the uptake and disposition of [14C]GB in male and female rats and mice administered 100 or 1000 mg/kg by gavage. [14C]GB was prepared by reaction of [2-14C]genipin with soy protein hydrolysate. Following administration in rats, 14C was eliminated primarily in feces (89-97% of administered dose), exhaled volatile organic chemical (VOC) and CO2 traps contained no radioactivity, and urine contained 0.2-0.4 %. In bile-duct-cannulated rats (100 mg/kg [14C]GB), 0.25% of dose was recovered in bile, and in urine, 0.5%. The percent of the dose absorbed was 0.9%, based on radioactivity in urine, bile, and carcass minus digestive tract contents. The highest level of radioactivity in tissues was in kidney; however renal recovery was low, with only 0.02-0.04% of the dose recovered in kidney. Repeated dosing indicated that 14C accumulated in kidney, and was slowly removed following cessation of dosing, consistent with previous studies, in the absence of any functional or histopathological changes.

How are plastic debris affecting the diet of the whitemouth croaker in the Southeastern Brazilian Bight?

The objective of this study was to analyze the presence of plastic debris in the digestive tract contents of Micropogonias furnieri, the most important demersal fish species from the Southeastern Brazilian Bight. In the laboratory, a total of 150 individuals were measured (230≤TL≤674 mm), weighed (136≤TW≤3221 g), and their gut contents were evaluated. The ingested food items were identified, and the plastic debris observed under the stereomicroscope were isolated and subjected to the physical analysis Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) to identify the chemical composition and to determine the polymers. A total of 190 plastic particles were observed in 51.8% of the stomachs containing food. The recovered plastic debris varied from one to twelve particles per individual (mean ± s.d. of 3.33 ± 2.25). Color varied and the particle size ranged from 0.075 to 19.139 mm. There was no relationship between the number of plastic debris recovered in the stomachs of M. furnieri and the total length, total weight, stomach weight, and percent repletion. The most common polymers were polyamide (28.42%), and polystyrene (27.37%), and the total value of polymer hazard index to M. furnieri diet was 35,544.77, corresponding to an extreme danger, with very toxic with long-lasting effects. Considering the effects of plastic ingestion by marine fish and the potential risks to human health, the contamination of the whitemouth croaker with items that are harmful to its diet reveals a problem of environmental contamination, an alarming concern about plastic pollution in marine systems.

Trophic interactions between common minke whales (Balaenoptera acutorostrata) and their prey during summer in the northern Barents Sea

Global warming is causing rapid change in marine food webs, particularly at northern latitudes where temperatures are increasing most rapidly. In this study, the diet of common minke whales Balaenoptera acutorostrata was assessed both in terms of short-term (morphological analyses of digestive tract contents) and longer-term (tissue chemical markers: fatty acids and stable isotopes) prey use in the northern Barents Sea to see if they are prey shifting. Samples (blubber cores, muscle, and stomach contents) were obtained from 158 common minke whales taken during Norwegian commercial whaling operations during summer over the period 2016–2020. Two prey items, capelin Mallotus villosus and krill (primarily Thysanoessa sp.), dominated the stomach contents in the entire period of investigation, which included sampling both in June and in August, similar to findings from earlier studies. A few gadoids were also observed in the whale stomachs. Lower blubber fatty acid (FA) contents in 2016/2017 as compared with 2018/2019 were observed. This is most likely explained by differences in sampling time (June in 2016/2017 vs August in 2018/2019, i.e., after a longer feeding period during the summer in the latter case). This explanation also fits with the fact that FA profiles of the 2018/2019 whales were more similar to the FA profiles of the potential prey, presumably reflecting the two months longer assimilation time for these whales. Multidimensional mixing models based on carbon and nitrogen isotope composition of the most likely prey groups suggested that the whales ate mostly krill in four of the five sampling years. In 2018 there were indications of a higher proportion of gadoid fish, showing some dietary flexibility. The trophic level of the whales’ feeding, as interpreted from the nitrogen isotope values, was positively correlated with blubber thickness suggesting that fish-eaters tended to assimilate more energy than whales that focused more exclusively on lower trophic prey. The variation suggested by different dietary analyses methods − stomach contents, fatty acids, and stable isotopes – most likely reflects different turnover times, with muscle stable isotopes likely representing several months of dietary integration, while lipid stores are more dynamic and may represent weeks, and stomach contents represent feeding events during the last few hours. The change in diet of minke whales from small pelagic fishes (in the past) to a greater quantity of krill and demersal fish (seen in this study) suggests that the whales are responding to the ongoing borealization of the Barents Sea ecosystem.

Constitutive Innate Immunity and Systemic Responses to Infection of the American Alligator (Alligator mississippiensis).

Uninfected alligators (Alligator mississippiensis) exhibited high constitutive levels of hepatic gene expression related to immune function, whereas the highest-expressed hepatic genes of uninfected mice were related to metabolism. Intraperitoneal challenge of mice with bacterial lipopolysaccharide results in dramatic inflammatory effects including peritoneal ascites, febrile response, dramatic alterations in electrophoretic serum profile, and mortality. In contrast, coelomic injection of alligators with 200× the murine LD50 of intraperitoneal bacterial lipopolysaccharide resulted in no changes in serum protein profiles, behavioral effects, mortality, and no coelomic ascites. However, injection of juvenile alligators with live bacteria resulted in a titer-dependent decrease in metabolic rate, as measured by oxygen consumption. These results are the opposite of those observed for mammalian and avian species. The decreased oxygen consumption was not accompanied by changes in heart or respiration rate, indicating that this phenomenon was not due to bradycardia or bradypnea. Interestingly, challenge of alligators with bacteria resulted in the complete expulsion of digestive tract contents within four hours. We interpret these activities as temporary minimization of other biological systemic activities to redirect and devote energy to immune function. The reallocation of resources within an organism to fight infection without increases in metabolic rate has not been described in other animals.

Short Communication: Aplocheilus panchax Hamilton, 1822 Found at Acidic Waters of Abandoned Ex-tin Mining Ponds as Insectivorous Fish and Its Role for Water Quality Improvement

Kepala timah fish or blue panchax is one of the species found at acidic waters of abandoned ex-tin mining pond. Kepala timah fish belongs to the extremophile fishes which can survive in extreme aquatic environments caused by pressure from environmental factors. This study aimed to confirm the kepala timah fish as a species of Aplocheilus panchax and to analyze its natural food habits. Molecular analysis through DNA barcoding was carried out by analyzing the COI gene and confirming the sequence of kepala timah fish in the gene bank on the NCBI website and constructing a phylogenetic tree for kepala timah fish to other A. panchax populations. Analysis of food habits was carried out by identifying the contents of the digestive tract of kepala timah fish which were observed microscopically. The results showed that kepala timah fish found at acidic waters of abandoned ex-tin mining pond was confirmed as Aplocheilus panchax Hamilton, 1822. Some morphological characters confirmed the similarity between kepala timah fish and A. panchax such as a silvery white spot on its head, terminal type of the mouth position, body shape was sagittiform, small dorsal fin on posterior body, and the shape of the caudal fin was rounded or rhomboid. Analysis of the contents of digestive tract showed the food habits of A. panchax found at acidic waters of ex-tin mining pond was insects. The food habits explained that A. panchax was classified as larvivorous or insectivorous fishes. The presence of A. panchax and its metabolic activity at abandoned ex-tin mining ponds can contributed to increasing organic matter in the waters so that it can be beneficial for improving water quality.

Feeding habits and diet composition of Octopus cyanea (Gray, 1849) in Zanzibar waters, Tanzania

The octopus fishery in Zanzibar is an essential activity of coastal communities. To assist with developing fisheries management plans, baseline information on the feeding of Octopus cyanea (Gray, 1849) was collected in relation to sex and maturity stages. The feeding habits and diet composition of 543 O. cyanea were studied over a period of 12 months at Paje, Kizimkazi, Chwaka Bay and Nungwi. Samples at each site were collected on two days per month during spring tide. Digestive tract contents revealed that O. cyanea preyed on 36 species of crustaceans, molluscs and fishes, with crabs a major prey item. The number of prey species in a single stomach ranged from one to six. O. cyanea in Zanzibar is therefore a generalist predator with a mixed diet. The octopus gonadosomatic index (GSI) indicated a peak breeding season in June to October, which correlated with low prey consumption. Mature octopuses ingested a small amount of food from mainly small sessile prey. Females consumed less food than males of similar maturity stages, suggesting that they ate less or had higher digestion rates. The information is useful for developing fisheries management plans for the octopus fishery in Zanzibar.

Lead speciation in body tissues, gastrointestinal contents, and feces of lead-exposed wild rats (Rattus rattus)

The toxic effects of lead (Pb) are an ongoing concern for which research continues to seek a solution. In Pb-contaminated areas, Pb concentrations in the environment and organisms are quantified to assess the degree of contamination. Understanding organismal uptake of Pb and its behavior in the body requires distinguishing Pb chemical species. We used Pb L3-edge X-ray absorption near-edge structure (XANES) to study the distribution of Pb species in body tissues, digestive tract contents, and feces of wild rats (Rattus rattus) collected from a heavily Pb-contaminated mining area in Zambia. Freeze-drying improved the XANES spectrum quality by approximately 10 μg-Pb/g-dry through concentrating the Pb without changing its chemical state from its wet state. We successfully identified and analyzed the Pb species in seven different tissues (bone, muscle, liver, kidney, spleen, lung, and brain), three different digestive-tract contents (stomach, small intestine, and colon), and feces from three wild rats. We described chemical-form-based details of Pb uptake and distribution that are common among rats, such as the increased Pb binding with thiol groups through the digestive system, distribution of mobile Pb to hematopoietic organs and vascular-related tissues, and Pb binding to thiol groups, especially in the liver and brain.

Management of giant myoma – case report and literature review

IntroductionUterine myomas are one of the most frequently discussed issues in gynecology. Most of them are asymptomatic, however, severe pain in pelvis minor, heavy uterine bleeding or infertility may be reported by the patients and worsen quality of women’s daily life. Giant myomas are very rare and can be directly life-threatening.AimThe aim of this study was to present a clinical case of giant myoma, its management and highlight the potential impact on women’s health and well-being.Case studyA 70-years-old patient with a pain in lower part of abdomen, constipation and tiredness manifested difficulties in breathing. Abdominal examination revealed a huge, elastic abdominal mass extending from xiphoid process to the pubic bone. A total abdominal hysterectomy with right salpingo-oophorectomy was done.The patient was discharged from the hospital on the day 9 after the surgery and recovered without any incident.Results and discussionPatients with giant uterine myomas may develop respiratory failure and require intensive respiratory care. One of the highest priorities should be adequate ventilation and reduction the vena cava compression. Cleansing the intestines before surgery decreases the risk of contamination the peritoneal cavity by digestive tract content, in case of possible extension of the scope of surgery.ConclusionsIn the case of treatment of large uterine myomas, interdisciplinary cooperation of specialists in various fields is necessary in order to protect the patient’s vital parameters and prevent the occurrence of rare complications.

Occurrence of potentially toxic microalgae and diarrhetic shellfish toxins in the digestive tracts of green sea turtles (Chelonia mydas) from southern Brazil

Algal toxins are involved in the mortality and/or illness of marine organisms via consumption of contaminated prey, or upon direct exposure to toxic cells. In this study, the presence of potentially toxic microalgal cells was investigated within the digestive tract contents of a threatened species of green turtle (Chelonia mydas). Additionally, lipophilic toxins were determined by LC-MS/MS in tissue samples (liver, stomach and/or intestine) of selected animals (n = 39 individuals) found dead-stranded in southern Brazil, from winter/2015 to autumn/2016. Thirteen potentially toxic species of microalgae (both benthic and planktonic), including seven dinoflagellates, six cyanobacteria and one diatom, were found in the digestive tract contents of green turtles. Among them, dinoflagellates belonging to the Dinophysis acuminata species complex were the most frequent (36%) and abundant (maximum average abundance of 566 cells g−1 in spring/2015). Moreover, 23% of the examined sea turtles exhibited detectable levels of the diarrhetic shellfish toxin okadaic acid (OA) in washed digestive tissues. Seven individuals accumulated OA in their intestines (max. 24.1 ng g−1) and two in the stomachs (max. 7.4 ng g−1). Toxin levels in the tissues were directly and significantly (r = 0.70, p < 0.025) associated with the cell abundance of OA-producing D. acuminata and Prorocentrum lima species complexes within the digestive contents of green turtles. Although OA concentrations were relatively low, possible chronic exposure might deteriorate general health conditions of exposed sea turtles, increasing the risk for diseases. Okadaic acid has been regarded as a tumor-promoting compound and an environmental co-factor in the incidence of fibropapillomatosis, a frequent disease in juvenile green turtles inhabiting this geographic region. Even though, only one green turtle containing OA in the digestive tissues (out of six examined) also presented fibropapillomatosis in this study. Notwithstanding, sea turtles are sentinels of ocean health. Monitoring the accumulation of algal toxins and their negative effects on these organisms contributes to conserving biodiversity and marine habitats.

Anthropophilic Small Mammals: Potential Source of Zoonotic Enteric Parasites in the Commune of Abobo, District of Abidjan (Côte d’Ivoire)

Objectives: This study aims to identify and assess intestinal parasites with zoonotic potential in terrestrial small mammals to better understand the associated risks. Methods: Live captures were performed using Sherman traps placed in human dwellings within the Abobo commune of Abidjan. Captured animals were euthanized and their legs were thoroughly washed with a Sodium Acetate Acetic Acid Formol solution. Subsequently, the digestive tract contents and leg washing fluids were examined using the Ritchie concentration method. Results: Mus musculus (75.3%) and Rattus rattus (13.5%) emerged as the most prevalent of small mammal species. Overall, 33.3% of these animals were infected with intestinal parasites. The predominant helminth species were Hymenolepis diminuta (8.9%) and Ancylostoma sp. (6.9%), while the primary pathogenic protozoa detected was Giardia intestinalis (2.3%). Conclusion: The presence of parasites of public health importance proves that cohabitation of small mammals with humans poses a significant risk to both public and veterinary health. These data therefore provide valuable information to local and provincial administrations, which should consider population control measures for small mammals to mitigate the transmission of zoonotic diseases to humans. They also provide information to medical practitioners for the diagnosis of possible zoonoses, and a reference for further studies in urban environments in Cote d'Ivoire.

Analysis of Microplastic Abundance in Lake Siombak, Medan Marelan, Medan

Microplastics are one of the pollutants that threaten aquatic ecosystems and have become the focus of research in recent years by environmentalists worldwide. In addition to harmful base materials, microplastics have hydrophobic characteristics, so chemicals such as Persistent Organic Pollutants can stick to microplastics and cause chemical pollution in aquatics. Siombak Lake is located in the coastal area of Medan City, and it is predicted to be a microplastic distribution channel to the aquatics. This study aimed to analyze the abundance of microplastics in water, sediment, and fish in Siombak Lake. Sampling was conducted from November 2021 – January 2022 at Siombak Lake. Water samples to be analyzed were added with 90 g NaCl, then filtered and separated visually using a microscope. Microplastic in the sediment is separated by drying, volume reduction, density separation, filtration, and visual sorting. Fish samples were dissected, and then the digestive tract content of fish was diluted with 10 ml of saturated NaCl. The abundance of microplastics obtained in waters ranged from 93-519 particles/m3, and the Number of microplastics in sediment ranged from 521-1481 particles/kg dry sediment, while the abundance of microplastics in fish samples ranged from 0-6 particles/individual.Keywords: Microplastic, Abundance, Coastal, Pollutant, Siombak Lake

Characterization of potential probiotics Lactobacillus species isolated from the gastrointestinal tract of Rhode Island Red (RIR) chicken in Ethiopia

Background and aimsNowadays, probiotic microorganisms are given high attention due to their potential for the improvement of animal production and productivity. The natural gut microflora of poultry can serve as an excellent source of optimum probiotic strains. Therefore, this study isolated, identified and characterized potential probiotic Lactobacillus strains from the digestive tract content of RIR chicken in Ethiopia. MethodsA total of five RIR chickens were randomly taken and a sample was taken from each gastrointestinal content for further analysis. For further characterization, among 190 isolates only 10 representative isolates were randomly taken for further in vitro probiotic potential characterization. The selected isolates were screened and identified based on the biochemical, morphological, and 16S rRNA gene sequences. ResultsSurvival isolates of IS3, IS4, IS6, and IS7 were significantly different (P < 0.05) at pH 2. IS3, IS4, IS6, and IS7 showed tolerance for 0.3% bile salt. Isolates of IS1, IS2, IS5, IS7, and IS8 were ampicillin-resistant, and chloramphenicol, ciprofloxacin, and erythromycin were used as antibiotics. All ten isolates showed antagonistic activity against Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Staphylococcus intermedius, and Salmonella enteritidis. The optimum temperature for all isolates was 45 °C, and all the isolates could grow at 0.69 mol/L of NaCl. Using phylogenetic analysis of the 16SrRNA gene sequence; IS3 was identified as Lactobacillus salivarius, while IS4, IS6, and IS7 were identified as Lactobacillus reuteri. ConclusionsThe results indicated that the selected Lactobacillus isolates can survive the stress conditions of the gastrointestinal tract and can thus be considered potential probiotic candidates for chickens.

Biomanipulation of Periphytic Algae in the Middle Route of South–North Water Diversion Project Canal: An In Situ Study in the Lushan Section

The biomanipulation technique has been developed and implemented for decades, yielding favorable results in various lakes both domestically and globally. This technology uses fish to reduce algae biomass, giving a natural and environmentally friendly solution to improve water quality. The effectiveness of biomanipulation technology in large-scale artificial water canals, on the other hand, has been unclear. To address this, from 15 December 2019 to 30 April 2020, an in situ experimental study on the biomanipulation of periphytic algae was conducted in the Lushan section of the main canal of the Middle Route of the South-to-North Water Diversion Project (MSNWDP). The study aimed to verify the control effect of fish on periphytic algae. Various combinations of Megalobrama terminalis and Xenocypris davidi were fixed on the canal with a triangular cylindrical cage, and their feeding effects on periphytic algae were observed. The results showed that the density of periphytic algae at the bottom of the cages was substantially lower than before the experiment, with a 68.75% average reduction. We graded the food-filling results based on the amount of digestive tract content, which was represented using Arabic numerals ranging from 0 to 5. The study discovered that M. terminalis had the best adaptability to the environment, with full intestines primarily composed of periphytic algae and a food-filling degree between grades 4 and 5. X. davidi, on the other hand, had a food-filling degree of 0. Furthermore, the weight of each M. terminalis increased significantly following the experiment, whereas the weight of each X. davidi decreased to varying degrees. Additionally, the study highlights the importance of selecting the appropriate fish species for biomanipulation, as different species may have varying levels of effectiveness in controlling periphytic algae. Overall, this study provides valuable insights into the potential of biomanipulation technology in large-scale artificial water canals and other water conservancy projects.

A chitosan-optimized polyethyleneimine/polyacrylic acid multifunctional hydrogel for reducing the risk of ulcerative arterial bleeding.

Ulcerative arterial bleeding is characterized by sudden onset, rapid disease development, and high mortality, which is a great challenge for clinicians to treat, specially bleeding in areas where endoscopic operation is difficult, or in the case of diffuse bleeding, tumor bleeding, and recurrent bleeding. Herein, we proposed a novel treatment strategy using biomaterials to protect the wound and isolate the erosion of digestive tract contents to prevent arterial bleeding in advance. By introducing chitosan to construct multihydrogen-bonding and an electrostatic interaction system, we developed polyethyleneimine/polyacrylic acid/chitosan (PEI/PAA/CS) multifunctional hydrogel. The new hydrogel is characterized by ultrafast gelation, strong tissue adhesion, gastric acid resistance, burst resistance, biocompatibility, hemostasis, and tissue repair. The addition of CS significantly improved the tissue adhesion, biocompatibility, hemostasis, and tissue repair ability of the hydrogel. The PEI/PAA/CS hydrogel could adhere to the ulcer surface and form a protective layer on the wound to prevent arterial bleeding. Importantly, the PEI/PAA/CS hydrogel also has the ability to stop bleeding and promote wound repair, which has been demonstrated in a variety of hemorrhage models in rats and rabbits. All of these factors indicate that the PEI/PAA/CS hydrogel is a promising biomaterial for reducing the risk of ulcerative arterial bleeding.

The Influence of Commercial Feed Supplemented with Carnobacterium maltaromaticum Environmental Probiotic Bacteria on the Rearing Parameters and Microbial Safety of Juvenile Rainbow Trout.

The aim of this study was to determine the effect of commercial feed (CF) supplemented with 0.1% of the Carnobacterium maltaromaticum environmental probiotic strain on the rearing parameters, apparent nutrient digestibility, and microbial safety of juvenile rainbow trout (Oncorhynchus mykiss). The fish were fed CF (control group, CG) and experimental feed (EF) supplemented with 0.1% of C. maltaromaticum (experimental group, EG) for 56 days. The final body weight and total body length of the fish were measured. The growth rate, condition factor, feed conversion ratio, viscerosomatic and hepatosomatic indices, and apparent digestibility coefficients of protein (PAD), lipids (LAD), ash (AAD), and nitrogen-free extract (NFEAD) were calculated. The total viable counts of C. maltaromaticum bacteria, mesophilic bacteria, hemolytic mesophilic bacteria, Pseudomonas fluorescens, Aeromonas hydrophila, Staphylococcus sp., and sulfite-reducing anaerobic spore-forming Clostridium sp. were determined in digestive tract contents and the skin of fish. Feed supplementation with C. maltaromaticum significantly affected most rearing parameters, as well as the PAD, LAD, AAD and NFE values, and bacterial counts. The principal component analysis (PCA) revealed significant positive correlations (p < 0.05) between fish growth rates, PAD and LAD values vs. C. maltaromaticum counts in the EF and in the digestive tract contents of the fish.

Diet of small mammals in semi‐deciduous forest fragments in Central Brazil

AbstractMarsupials and rodents are two of the most specious mammalian group, displaying a variety of diet and feeding habits. However, the knowledge about diet for several small mammal species is scant in the scientific literature, and most species are classified as insectivore–omnivore (marsupials), or frugivore–graminivore (rodents). In this study, we described diet composition based on digestive tract contents of 12 species of small mammals (7‐rodents and 5‐marsupials), in semi‐deciduous forest fragments of Central Brazil. We analysed 47 digestive tract contents belong to Calomys tener (10), Oecomys bicolor (10), Gracilinanus agilis (6), Marmosa murina (5), Rhipidomys macrurus (5), Calomys expulsus (2), Cryptonanus chacoensis (2), Monodelphis kunsi (2), Oecomys catherinae (2), Caluromys philander (1), Oligoryzomys mattogrossae (1) and Necromys lasiurus (1). We found parts of arthropods and fruits in the digestive tract of all species, with the exception of N. lasiurus, which contained only arthropods. The most representative arthropod taxa were Hymenoptera (present in 11 species), Coleoptera (9 spp.), Arachnida (7 spp.) and Isoptera (6 spp.). The seeds of Piperaceae (present in 3 small mammal species), Myrtaceae (2 spp.) and Poaceae (1 sp.) were also identified. This study reports the first records of diet composition for the marsupials C. chacoensis and M. murina, and rodents C. expulsus, C. tener, O. bicolor, O. catherinae and R. macrurus. Our findings contribute to understanding the diet composition and natural history of the Brazilian Savanna small mammals.

The dominant species of piscivorous bird does not adversely affect fishery in the lagoons of the southern Baltic Sea

The impact of fish-eating birds on fishery has long been debated. It is therefore important that the arguments in this debate be scientifically based. The Great Cormorant Phalacrocorax carbo is a flagship example of a conflict species that has been well studied. In some areas, however, such as the southern Baltic estuarine lagoons, the Goosander Mergus merganser may be more abundant, exerting a potentially greater impact on fisheries. However, this aspect has not been well studied in this region, so this article is an attempt to fill this knowledge gap. Based on the digestive tract content of 23 Goosander drowned in gillnets in Poland, it was found that the most frequently consumed species was Ruffe Gymnocephalus cernua (70% of biomass), followed by Zander Sander lucioperca (13% of biomass), Perch Perca fluviatilis (9% of biomass) and Roach Rutilus rutilus (8% of biomass). Average Goosander numbers in the Vistula and Odra estuaries in 2011–2018 were 11,000 in winter, 4,500 in spring and 2,800 in autumn. These fish-eating ducks were found to consume 242 t of fish annually during this period, whereas at the same time fishermen caught an average of 4,400 t of fish. The species caught by both Goosander and fishermen were mainly Zander (32 t vs 189 t), Perch (21 t vs 668 t) and Roach (19 t vs 701 t). No negative impact of Goosander foraging in the winter preceding the fishery season was demonstrated for any of the above species (Zander R2 = 0.022; Perch R2 = 0.834; Roach R2 = 0.881).

Ingestion and characterization of plastic debris by loggerhead sea turtle, Caretta caretta, in the Balearic Islands

Plastic waste has become ubiquitous pollutants in seas and oceans and can affect a wide range of species. For some marine species, plastic debris could pose a considerable threat through entanglement, ingestion, and habitat degradation and loss. Sea turtles are one of the most sensitive species, as their migratory behaviour and multifaceted life cycles make these reptiles especially vulnerable to the negative effects of plastic debris. The present study aimed to assess the amount and composition of plastic debris ingested by loggerhead turtles (Caretta caretta, Linnaeus, 1758) in the Balearic Islands Sea, thusly providing new information to complete the knowledge for this topic. In this work, 45 stranded dead C. caretta specimens were necropsied, and their digestive tract content analysed for the presence of plastic debris. Plastic objects were observed in 27 individuals (60.0%), with an average of 12.7 ± 4.7 plastic items per turtle. Litter in the faecal pellet was also monitored in 67 living individuals, observing plastic elements in 46 (68.7%) of the specimens, reporting an average of 9.7 ± 3.3 plastic elements per individual. Overall, 785 plastic items were found, measured, weighed and categorized according to size, colour, shape, and type of polymer. The main elements ingested were plastic sheets that were found in 65.3% of the turtles analysed, being white (42.7%) and transparent (29.2%) the most predominant colours. Most elements were macroplastics (59.3%), while microplastics were not found. Fourier Transform Infrared Spectrometry (FT-IR) analysis showed that high-density polyethylene and polypropylene were the main polymer plastics, representing 42.3% and 33.8% of the total, respectively. In conclusion, the high occurrence of plastic debris determined in the present study evidenced for the first time plastic ingestion in loggerhead turtles in the Balearic Islands, and highlights C. caretta as a bioindicator organism for marine pollution.

Patterns of Herbivory in Neotropical Forest Katydids as Revealed by DNA Barcoding of Digestive Tract Contents.

Many well-studied animal species use conspicuous, repetitive signals that attract both mates and predators. Orthopterans (crickets, katydids, and grasshoppers) are renowned for their acoustic signals. In Neotropical forests, however, many katydid species produce extremely short signals, totaling only a few seconds of sound per night, likely in response to predation by acoustically orienting predators. The rare signals of these katydid species raises the question of how they find conspecific mates in a structurally complex rainforest. While acoustic mechanisms, such as duetting, likely facilitate mate finding, we test the hypothesis that mate finding is further facilitated by colocalization on particular host plant species. DNA barcoding allows us to identify recently consumed plants from katydid stomach contents. We use DNA barcoding to test the prediction that katydids of the same species will have closely related plant species in their stomach. We do not find evidence for dietary specialization. Instead, katydids consumed a wide mix of plants within and across the flowering plants (27 species in 22 genera, 16 families, and 12 orders) with particular representation in the orders Fabales and Laurales. Some evidence indicates that katydids may gather on plants during a narrow window of rapid leaf out, but additional investigations are required to determine whether katydid mate finding is facilitated by gathering at transient food resources.

Release and intestinal translocation of chemicals associated with microplastics in an in vitro human gastrointestinal digestion model

The global production of plastic currently exceeds 300 million tonnes per year. The extensive use of plastics and bad waste management has resulted in the presence of microplastics at different levels in the food production chain. From a chemical perspective, these microplastics are complex mixtures that contain multiple additives, such as plasticizers, flame retardants, stabilizers and pigments. Also other chemicals can be present in microplastics, including unreacted monomers, starting substances, and non-intentionally added substances. Finally, the microplastics may have adsorbed environmental contaminants. In this study we have used several types of microplastics, either from grinded beach litter or from frequently used food packing materials and pre-production samples. We quantified the chemical and metal release from these microplastics in worst case and physiological scenarios. We use a chemical extraction as worst case, and for the physiological scenarios we used an in vitro model of the human digestion and an in vitro model of the human intestinal epithelium. Subsequently all samples were analysed with sensitive ICP-MS, GCMS methods. We quantified 68 chemicals and 29 metals associated with a diversity of microplastics, some of these chemicals were also released in the luminal content of the human digestive tract under physiological conditions simulated in vitro. Only 22 chemicals reached the basolateral compartment of an in vitro intestinal epithelial model. From the ToxCast dataset we extracted 18 AOPs that were associated with the chemicals, that included AOPs associated with endocrine disruption. For a risk assessment of chemicals associated with microplastics more detailed data on oral microplastics exposure is needed, as well as more detailed toxicological studies on the hazards of both the individual and complex mixtures of the quantified chemicals.