Middle Gut Research Articles

Synergistic Effect of Dietary Supplementation with Sodium Butyrate, β-Glucan and Vitamins on Growth Performance, Cortisol Level, Intestinal Microbiome and Expression of Immune-Related Genes in Juvenile African Catfish (Clarias gariepinus).

The effect of dietary supplementation with sodium butyrate, β-glucan and vitamins (A, D3, E, K, C) on breeding indicators and immune parameters of juvenile African catfish was examined. The fish were fed with unenriched (group C) and enriched feed with a variable proportion of sodium butyrate/β-glucan, and constant content of vitamins (W1-W3). After the experiment, blood and the middle gut were collected. The microbiome of the gut was determined using Next Generation Sequencing (NGS). Liver tissue was collected for determination of expression of immune-related genes (HSP70, IL-1β, TNFα). W2 and W3 were characterized by the most favorable values of breeding indicators (p < 0.05). The highest blood cortisol concentration was in group C (71.25 ± 10.45 ng/mL), and significantly the lowest in W1 (46.03 ± 7.01 ng/ mL) (p < 0.05). The dominance of Cetobacterium was observed in all study groups, with the largest share in W3 (65.25%) and W1 (61.44%). Gene expression showed an increased number of HSP70 genes in W1. IL-1β and TNFα genes peaked at W3. The W3 variant turns out to be the most beneficial supplementation, due to the improvement of breeding and immunological parameters. The data obtained can be used to create a preparation for commercial use in the breeding of this species.

Gut-Brain Axis a Key Player to Control Gut Dysbiosis in Neurological Diseases.

Parkinson's disease is a chronic neuropathy characterised by the formation of Lewy bodies (misfolded alpha-synuclein) in dopaminergic neurons of the substantia nigra and other parts of the brain. Dopaminergic neurons play a vital role in generating both motor and non-motor symptoms. Finding therapeutic targets for Parkinson's disease (PD) is hindered due to an incomplete understanding of the disease's pathophysiology. Existing evidence suggests that the gut microbiota participates in the pathogenesis of PD via immunological, neuroendocrine, and direct neural mechanisms. Gut microbial dysbiosis triggers the loss of dopaminergic neurons via mitochondrial dysfunction. Gut dysbiosis triggers bacterial overgrowth in the small intestine, which increases the permeability barrier and induces systemic inflammation. It results in excessive stimulation of the innate immune system. In addition to that, activation of enteric neurons and enteric glial cells initiates the aggregation of alpha-synuclein. This alpha-synucleinopathy thus affects all levels of the brain-gut axis, including the central, autonomic, and enteric nervous systems. Though the neurobiological signaling cascade between the gut microbiome and the central nervous system is poorly understood, gut microbial metabolites may serve as a promising therapeutic strategy for PD. This article summarises all the known possible ways of bidirectional signal communication, i.e., the "gut-brain axis," where microbes from the middle gut interact with the brain and vice versa, and highlights a unique way to treat neurodegenerative diseases by maintaining homeostasis. The tenth cranial nerve (vagus nerve) plays a significant part in this signal communication. However, the leading regulatory factor for this axis is a diet that helps with microbial colonisation and brain function. Short-chain fatty acids (SCFAs), derived from microbially fermented dietary fibres, link host nutrition to maintain intestinal homeostasis. In addition to that, probiotics modulate cognitive function and the metabolic and behavioural conditions of the body. As technology advances, new techniques will emerge to study the tie-up between gut microbes and neuronal diseases.

Exogenous enzymes and probiotics alter digestion kinetics, volatile fatty acid content and microbial interactions in the gut of Nile tilapia

Sustainable aquafeed production requires fishmeal replacement, leading to an increasing use of plant-derived ingredients. As a consequence, higher levels of antinutritional substances, such as non-starch polysaccharides and phytate, are present in aquafeeds, with negative effects on fish performance, nutrient digestibility and overall gut health. To alleviate these negative effects, providing exogenous digestive enzymes and/or probiotics can be an effective solution. In this study, we tested the effect of dietary supplementation of enzymes (phytase and xylanase) and probiotics (three strains of Bacillus amyloliquefaciens) on nutrient digestion kinetics and volatile fatty acid content along the gut, and the distal gut microbiome diversity in Nile tilapia. Chyme volatile fatty content was increased with probiotic supplementation in the proximal gut, while lactate content, measured for the first time in vivo in fish, decreased with enzymes along the gut. Enzyme supplementation enhanced crude protein, Ca and P digestibility in proximal and middle gut. Enzymes and probiotics supplementation enhanced microbial interactions as shown by network analysis, while increased the abundance of lactic acid bacteria and Bacillus species. Such results suggest that supplementation with exogenous enzymes and probiotics increases nutrient availability, while at the same time benefits gut health and contributes to a more stable microbiome environment.

Protective effect of nutraceutical food on the intestinal mucosa of juvenile pacu Piaractus mesopotamicus under high stocking density

Nutraceuticals have been evaluated for their ability to protect and heal the gastrointestinal mucosa, especially in adverse conditions. Thus, the present study evaluated the effect of a nutraceutical diet composed of bovine first milk secretion in the intestinal health of juvenile Piaractus mesopotamicus subjected to high stocking density. Juveniles (140 ± 10 g) distributed into 16 cages and stocked at 50 kg m−3 were fed twice daily with a pelleted and semi-purified diet containing nutraceutical food (NF) in increasing levels, being 0, 10, 20, and 30% of inclusion (n = 4). Quantification of goblet cells containing neutral, acidic (including sialo and sulfomucins) and acidic-neutral mucins, volume (Vv), and surface density (Sv) of the mucosa and thickness of the internal circular muscle layer was determined after 28 experimental days in the middle gut and rectum (RT). The apoptotic rate was analyzed qualitatively according to the intensity (high, medium, and low) of caspase-3 immunostaining in epithelial cells. Performance parameters were not affected by the inclusion of NF in the diets. Juveniles fed 20% and 30% of NF showed a lower number of goblet cells containing sulfomucins than juveniles fed 0% and 10% of NF (P = 0.01) in the RT. In the last segment of the middle gut (S2) and RT, the intensity of caspase-3 immunostaining in enterocytes was inversely related to the concentration of NF added in the diet. The inclusion of 20% and 30% of nutraceutical food in the diet of P. mesopotamicus reduced the rate of apoptosis and the number of goblet cells containing sulfomucin in the last intestinal segments of juveniles subjected to high stocking density, mitigating the effects caused by the adverse condition and being, therefore, beneficial for intestinal health.

Bmo-miR-2780a regulates the expression of the sericin-1 gene of Bombyx mori.

Silk production in Bombyx mori L. is largely determined by the expression of genes encoding fibroin and sericin. Here, we examined the regulatory function of a microRNA (miRNA) on silk gene expression using the sericin-1 gene (BmSer-1). First, we downloaded whole mature miRNAs of silkworm from miRBase and identified bmo-miR-2780a as a candidate miRNA for the regulation of BmSer-1 expression. We used semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) with stem-loop primers to investigate the expression profile of bmo-miR-2780a and its predicted target gene BmSer-1 in seven different tissues from 5th instar day-3 larvae, including head, fat body, anterior silk gland (ASG), middle silk gland (MSG), posterior silk gland (PSG), middle gut, and hemolymph. Our results showed that bmo-miR-2780a was specifically expressed in the MSG and that the expression level of BmSer-1 was significantly higher in the MSG than in other tissues. Recombinant plasmids carrying both pri-mir-2780a and Ser1-3'UTR were constructed and then used to cotransfect BmN cells. We further detected the effect of bmo-miR-2780a on Ser-1 in vivo. These results showed that the target gene was significantly decreased by miR-2780a compared with the control group (p < .05), thus indicating that bmo-miR-2780a might negatively regulate the expression of Ser-1.

GLP-1 mediated improvement of the glucose tolerance in the T2DM GK rat model after massive jejunal resection

ObjectiveThe aim of this study was to clarify the role of the middle gut in the entero-pancreatic axis modification that leads to glucose improvement in the Goto-Kakizaki (GK) rat as a non-obese T2DM model. BackgroundBariatric surgery is considered an assured solution for type 2 Diabetes (T2DM). Enterohormones such as ghrelin, gastric inhibitory polypeptide and mainly glucagon-like peptide-1 (GLP-1) were recognized as key players in the physiophathological mechanisms associated with entero-pancreatic axis regulation and glucose tolerance improvement. However, the influence of anatomical arrangements post-bariatric surgery on this axis is still debatable. MethodTo this purpose, 50% of small intestine resections were performed on GK rats (n = 6), preserving the proximal half of the jejunum and the ileum (IR50). Phenotypic and functional changes, such as performance in oral glucose tolerance tests, ileal release of GLP-1, beta-cell sensitivity to GLP-1, beta-cell mass, and turnover were characterized in IR50 and the surgical control group (Sham). ResultsThe glucose tolerance was improved and ileal release of GLP-1 was enhanced four weeks after IR50 versus the control group rats. Beta-cell mass, beta-cell proliferation, and beta-cell sensitivity to GLP-1 were also increased in the pancreas of IR50 versus the control group rats. Conclusionthe jejunal exclusion increases beta-cell-mass and improves glucose tolerance by increasing in GLP-1 expression and number of receptors via the entero-pancreatic axis.

C-Type allatostatin and its putative receptor from the mud crab serve an inhibitory role in ovarian development.

C-Type allatostatins are a family of peptides that characterized by a conserved unblocked PISCF motif at the C-terminus. In insects, it is well known that C-type allatostatin has a potent inhibitory effect on juvenile hormone biosynthesis by the corpora allata. C-Type allatostatin has been widely identified from crustacean species but little is known about its roles. Therefore, this study investigated the tissue distribution patterns of C-type allatostatin and its putative receptor in the mud crab Scylla paramamosain, and further explored its potential effect on vitellogenesis. Firstly, cDNAs encoding C-type allatostatin (Sp-AST-C) precursor and its putative receptor (Sp-AST-CR) were isolated. Subsequently, RT-PCR revealed that Sp-AST-C was mainly expressed in the nervous tissue, middle gut and heart, whereas Sp-AST-CR had extensive expression in all tissues tested except the eyestalk ganglion and hepatopancreas. In addition, in situ hybridization in the cerebral ganglion showed that Sp-AST-C was localized in clusters 6 and 8 of the protocerebrum, clusters 9, 10 and 11 of the deutocerebrum, and clusters 14 and 15 of the tritocerebrum. Whole-mount immunofluorescence revealed a similar distribution pattern. Synthetic Sp-AST-C had no effect on the abundance of S. paramamosain vitellogenin (Sp-Vg) in the hepatopancreas and ovary in vitro but significantly reduced the expression of its receptor (Sp-VgR) in the ovary in a dose-dependent manner. Furthermore, Sp-VgR expression, vitellin content and oocyte diameter in the ovary were reduced 16 days after the first injection of Sp-AST-C. Finally, in situ hybridization showed that Sp-AST-CR transcript was specifically localized in the oocytes, which further indicated that the oocytes are the target cells for Sp-AST-C. In conclusion, our results suggested that the Sp-AST-C signaling system is involved in the regulation of ovarian development, possibly by directly inhibiting the uptake of yolk by oocytes and obstructing oocyte growth.

Austrogena: a new genus of chemosymbiotic bivalves (Bivalvia; Vesicomyidae; Pliocardiinae) from the oxygen minimum zone off central Chile described through morphological and molecular analyses

A new genus, Austrogena, is established for a new species of vesicomyid bivalve (A. nerudai sp. nov.) described from sediments within the oxygen minimum zone off El Quisco, Chilean margin (∼33°S) from ∼340 m depth. The new genus is distinguished by a unique combination of conchological and anatomical features for vesicomyids, including the presence of an escutcheon, a lunular incision, an elongated 4-b tooth in the left valve, a subumbonal pit, both inner and outer pairs of demibranchs and the absence of pallial sinus and processes on the inner vulva of the inhalant siphon. In comparison with the majority of highly specialized pliocardiins, the alimentary gut of Austrogena is not straight and its middle gut changes direction twice. Molecular analysis, based on COI sequences, confirms that A. nerudai sp. nov. is not related to any other pliocardiin. So far, Austrogena gen. nov. is the only endemic vesicomyid genus in the south-eastern Pacific area and A. nerudai sp. nov. is the fourth species of vesicomyids reported from chemosynthetic communities of the Chilean margin. The description of the new genus further contributes to knowledge of biodiversity of chemosymbiotic assemblages in the south-eastern Pacific.http://zoobank.org/urn:lsid:zoobank.org:pub:476A9734-B510-4954-A623-2C0E1F254F9A.

Antigen-dependent T lymphocytes (TcRβ +) are primarily differentiated in the thymus rather than in other lymphoid tissues in sea bass ( Dicentrarchus labrax, L.)

All jawed vertebrates share lymphocyte receptors that allow the recognition of pathogens and the discrimination between self and non-self antigens. The T cell transmembrane receptor (TcR) has a central role in the maturation and function of T lymphocytes in vertebrates via an important role in positive selection of the variable region of TcR αβ/γδ chains. In this study, the TcRβ transcript expression and TcRβ + cell distribution during the ontogeny of the immune system of sea bass ( Dicentrarchus labrax, L.) were analysed. RT-PCR analysis of larvae during early development demonstrated that the β chain transcript is expressed by 19 days post-fertilisation (p.f.). RNA probes specific for the β chain were synthesised and used for in situ hybridisation experiments on 30 day p.f. to 180 day old juvenile larvae. A parallel immunohistochemical study was performed using the anti-T cell monoclonal antibody DLT15 developed in our laboratory [Scapigliati et al., Fish Shellfish Immunol 1996; 6:383–401]. The first thymus anlage was detectable at 32–33 days p.f. (Corresponding to about 27 days post-hatch). DLT15 + cells were detected at day 35 p.f. in the thymus whereas TcRβ + cells were recognisable at day 38 p.f. in the thymus and at day 41 p.f. in the gut. TcRβ + cells were observed in capillaries from 41 to 80 days p.f. At day 46 p.f., TcRβ + cells were identified in the head kidney and were detected in the spleen 4 days later. The present results demonstrate that TcRβ + cells can be differentiated first in the thymus and then in other organs/tissues, suggesting potential TcRβ + cell colonisation from the thymus to the middle gut. Once the epithelial architecture of the thymus is completed with the formation of the cortical-medullary border (around 70–75 days p.f.), DLT15 + cells or TcRβ + cells are confined mainly to the cortex and cortical-medullary border. In particular, a large influx of TcRβ + cells was observed at the cortical-medullary border from 72 to 90 days p.f., suggesting a role in positive selection for this thymic region during the ontogeny of the fish immune system. This study provides novel information about the primary differentiation and distribution of TcRβ + cells in sea bass larvae and juveniles.

Quantitative analysis of cytoplasmic actin gene promoter and nuclear polyhedrosis virus immediate-early promoter activities in various tissues of silkworm &amp;lt;italic&amp;gt;Bombyx mori&amp;lt;/italic&amp;gt; using recombinant &amp;lt;italic&amp;gt;Autographa californica&amp;lt;/italic&amp;gt; nuclear polyhedrosis virus as vector

Cassettes harboring luciferase reporter driven by Bombyx mori cytoplasmic actin gene promoter (A3) (671 bp) and B. mori nuclear polyhedrosis virus immediate-early promoter (IE-1) (580 bp) were transferred to the bacmid AcDeltaEGT to generate the recombinant Autographa californica nuclear polyhedrosis viruses, AcNPVA3Luc and AcNPVIELuc, respectively. Recombinant baculoviruses were injected into the hemocoele of newly ecdysed 5th instar larvae. The activities of the A3 and IE-1 promoters in various tissues were measured by luciferase activity assay and normalized by the copy number of recombinant virus. Results showed that the activity of the A3 promoter was approximately 10-fold higher than the IE-1 promoter. The promoter activities of A3 and IE-1 were highest in the silk gland, followed by fat body, middle gut, malpighian tubule, and hemocyte. In silk gland, activity of the two promoters was highest in posterior silk gland, followed by middle and anterior silk glands. The difference in promoter activities reflects the growth speed of tissue in silkworm larvae. The activity of the A3 promoter remained unchanged and was not inhibited significantly by viral factors at least 3-4 d post injection of rAcNPV.

Spread of recombinant Autographa californica nucleopolyhedrovirus in various tissues of silkworm Bombyx mori determined by real-time PCR

A cassette harboring luciferase reporter driven by Bombyx mori A3 promoter was transferred to the bacmid AcΔEGT to generate the recombinant virus AcNPVA3Luc (where Ac represents Autographa californica, NPV represents nucleopolyhedrovirus, and A3Luc represents the firefly luciferase reporter cassette driven by the A3 promoter). Recombinant baculovirus was injected into the hemocoele of newly ecdysed fifth instar larvae of the silkworm. The infection of virus in various silkworm tissues was determined by real-time PCR. The profile of viral infection showed that the copy number of recombinant AcNPV (rAcNPV) increased the fastest in the hemocyte, followed by the fat body, Malpighian tubule, middle gut, and silk gland. Detecting in nonpermissive strain silkworm showed that there was no significant difference in the entry of rAcNPV into all tested tissues. The difference in viral infection reflected mainly the big difference in replication of rAcNPV in various tissues of silkworm larvae. Real-time quantitative RT–PCR showed that it was due to the different expression of genes involved in viral DNA replication.

느타리 재배에서 버섯파리의 생물학적 방제를 위한 곤충병원성 세균의 분리 및 동정

느타리버섯 재배에 있어서 주요해충인 버섯파리 Lycoriella mali의 생물학적 방제를 위하여 전국 느타리버섯 재배지와 버섯파리의 병사충에서 버섯파리 유충에 병원성을 갖는 세균 8균주를 분리하였다. 이 중 Bti-D 및 Bti-U 2균주에 의한 사충율이 각각 82.3%와 87.3%로 가장 높았다. 버섯파리 유충의 발육단계에 따른 살충 효과 검정에서는 두 균주 모두 3령 층에서 높은 살충효과를 보였다. 이들 세균으로 감염된 유충에 나타나는 병징으로서 감염초기에는 중장의 앞부분이 연한 갈색을 띄고, 차츰 중장의 뒷부분까지 진행되어 전 부분이 흑갈색으로 변색되면서 치사되었다. 이들 두 균주를 동정하기 위하여 배양적, 생화학적 및 생리적 특성을 조사하고 Bergey's manual과 Biolog system을 동정에 이용하였으며, 주사전자현미경으로 세포형태를, 위상차현미경으로 내생포자와 내독소를 관찰하여 판정한 결과, 두 균주 모두 Bacillus thuringiensis로 동정되었으며, 편모항원성을 조사한 결과, B. l. subsp. israelensis로 동정되었다. The study was conducted to isolate and identify insecticidal bacteria for biological control of larvae of mushroom fly, Lycoriella mali, which is one of serious pests to oyster mushrooms during its cultivation period. Among eight bacteria isolated from the soil in the oyster mushroom beds and the dead body of L. mali, two bacteria, Bti-D and Bti-U showed more toxicity with mortality rate than other six-bacteria isolates. The two bacteria showed more toxicity in three instar of the period of development of the mushroom fly than in other instar. Symptoms of the larvae of L. mali infected by the two bacteria developed as follows: at the early infection, the front middle gut changed color to light brown, the middle gut to brown, whole body to black brown, and eventually, the fly died. For the identification of these isolates, cultural and biochemical characteristics by Bergey's manual and Biolog system, cell morphology by TEM, endospore and endotoxin by phase-contrast microscope, and test using 33H antisera were examined. According to the results, these two isolates, Bti-D and Bti-U were identified as Bacillus thuringiensis subsp. israelensis respectively.

Nahrung und Freßverhalten bei Sedimentfressern dargestellt am Beispiel von Sipunculiden und Holothurien

Using a Phillipson microbomb calorimeter, the energy values of the “infauna-substrate-feeders”Sipunculus nudus andPhascolosoma vulgare and the nutritive value of their food substrate were determined. Calorific measurements were made of the total food substrate, of meiofauna organisms living in it and of fecal pellets from other invertebrate animals which are an important part in the food supply. Analyses of the gut content of the sipunculids and their feces were compared with the surrounding sediment. The total sediment had an ash content of about 97%, and an energy content of approximately 0.14 cal mg−1 dry weight; this is equivalent to 165 kcal m−2. For the meiofauna in this substrate a biomass of 800 mg dry weight was calculated. Using calorific determinations of important meiofauna groups (nematodes 5274 kcal kg−1, ostracods 5884 and 6000 kcal kg−1), one square meter of the sediment surface — the sipunculid food source — yielded a caloric content of 3.78 kcal for the meiofauna, which means a contribution of 2.3% to the total food substrate. The largest part of the calorific contents is by far provided by fecal pellets with 0.6 cal mg−1 dry weight or 150 kcal m−2; this accounts for 92% of the total calorific content of the food substrate. Peritrophic membranes and attached microorganisms may be responsible for this spectacularly high value. Coprophagy plays an important role. The rest of the total value was contributed by particulate and dissolved detritus as well as protozoans with a calculated sum of 10 kcal m−2 or 6%. Food uptake is selective with regard to small sediment grain sizes. The amount of meiofauna in the gut is 80 times lower than in the surrounding environment, the energy content in the anterior gut 10 times higher. The energy loss inS. nudus from the anterior gut to the middle gut is more than 70%, to the posterior gut a further loss of 19% was observed. Calorific measurements in the feces were no longer possible. The utilization of food appears to be almost 100%. A correlation between ash content and the quantity of the sand grain-size fraction 37–125 μm and the calorific content is shown. The meiofauna does not represent a significant part of the total food structure, but it is taken up and utilized as food by the sediment feeding macrofauna.

Versuche zur Frage der Futterverteilung und Wasseraufnahme beiFormica polyctena (Först.)

The distribution of food in outside workers ofFormica polyctena is determined by begging time and not by the sequence in which the ants are fed. Larger ants are given no preference in feeding. In thirsty condition ants take in, besides normal water, also the soil capillary water. It will be faster conducted to the middle gut than honey solution.

Über eine bakterielle Vorverdauung und eine proteolytische Hauptverdauung im Darm der Nashornkäferlarve (Oryctes nas. L.)

The larva ofOryctes nas. L. shows a bacterial predigestion in the rectal-saccus. The main breakdown of proteins takes place in the middle gut, closely connected with the act of regurgitation.