Dietary Administration of Lactobacillus plantarum Enhanced Growth Performance and Innate Immune Response of Siberian Sturgeon, Acipenser baerii

Angiotensin-converting enzyme inhibitory peptide IVGFPAYGH protects against liver injury in mice fed a high‑sodium diet by inhibiting the RAS and remodeling gut microbial communities

Consuming a high‑sodium diet carries serious health risks and significantly influences the activation state of the renin-angiotensin system (RAS). This study evaluates the protective effect of angiotensin-converting enzyme (ACE) inhibitory peptide IVGFPAYGH on a high‑sodium diet-induced liver injury. IVGFPAYGH supplementation increased the activities of liver antioxidase and decreased the levels of liver inflammatory factor in mice fed a high‑sodium diet (8 % NaCl). IVGFPAYGH supplementation also reduced liver fatty acid synthesis and promoted fatty acid oxidation, increased the expression of low-density lipoprotein receptor, and improved liver dyslipidemia. Furthermore, IVGFPAYGH supplementation inhibited the activation of the liver RAS via inhibiting ACE activity and reducing angiotensin II levels in mice fed a high‑sodium diet. Moreover, IVGFPAYGH supplementation could alter the gut microbiota composition toward a normal gut microbiota composition and increase the abundance of the Lactobacillus genus. IVGFPAYGH supplementation also increased the expression levels of small intestinal tight junction protein and cecum short-chain fatty acids. Thus, IVGFPAYGH supplementation may maintain intestinal homeostasis and improve high‑sodium diet-induced liver injury by altering the gut microbiota composition and inhibiting the RAS. IVGFPAYGH is a promising functional ingredient for protecting liver damage caused by a high‑sodium diet.

Changes in the gut microbiota structure and function in rats with doxorubicin-induced heart failure

Objectives

The rat model of heart failure (HF) induced by doxorubicin (DOX), a broad spectrum and highly effective chemotherapeutic anthracycline with high-affinity to myocardial tissue that causes severe dose-dependent irreversible cardiotoxicity has been widely recognized and applied in HF pathogenesis and drug therapy studies. The gut microbiota (GM) has attracted significant attention due to its potential role in HF, and research in this area may provide beneficial therapeutic strategies for HF. Considering the differences in the route, mode, and total cumulative dose of DOX administration used to establish HF models, the optimal scheme for studying the correlation between GM and HF pathogenesis remains to be determined. Therefore, focusing on establishing the optimal scheme, we evaluated the correlation between GM composition/function and DOX-induced cardiotoxicity (DIC).

Methods

Three schemes were investigated: DOX (at total cumulative doses of 12, 15 or 18 mg/kg using a fixed or alternating dose via a tail vein or intraperitoneal injection) was administered to Sprague Dawley (SD) for six consecutive weeks. The M-mode echocardiograms performed cardiac function evaluation. Pathological changes in the intestine were observed by H&E staining and in the heart by Masson staining. The serum levels of N-terminal pre-B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) were measured by ELISA. The GM was analysed by 16S rRNA gene sequencing.

Key findings

Strikingly, based on the severity of cardiac dysfunction, there were marked differences in the abundance and grouping of GM under different schemes. The HF model established by tail vein injection of DOX (18 mg/kg, alternating doses) was more stable; moreover, the degree of myocardial injury and microbial composition were more consistent with the clinical manifestations of HF.

Conclusions

The model of HF established by tail vein injection of doxorubicin, administered at 4mg/kg body weight (2mL/kg) at weeks 1, 3 and 5, and at 2mg/kg body weight (1mL/kg) at weeks 2, 4 and 6, with a cumulative total dose of 18mg/kg, is a better protocol to study the correlation between HF and GM.

Natural Feed Supplements Improve Growth, Non-Specific Immune Responses and Resistance against Vibrio alginolyticus in Lates calcarifer

This study aimed to investigate the effects of dietary natural feed supplement on the growth performance, non-specific responses, and disease resistance in Lates calcarifer. Three commercial products (A, B, and C) containing a basal probiotic mixture were tested. Product A contained a basal mixture of Paenibacillus sp., Bacillus subtilis, Bacillus amyloliquefaciens, and Lactobacillus rhamnosus (107 cfu/g for each probiotic); product B contained additional Lactobacillus plantarum (1010 cfu/g); and product C contained additional soybean peptides (500 g/kg) and garlic powder (1 g/kg). Each product was supplemented into subject diets at dosages of 1 or 2 g/kg (designated as the A1, A2, B1, B2, C1, and C2 groups, respectively). Following an eight-week trial, growth parameters (specific growth rate and feed conversion ratio), non-specific immune responses (O2− production, phagocytic rate, and phagocytic index), and the results of a challenge test against Vibrio alginolyticus were evaluated. The results show that all probiotic supplement groups exhibited an improvement in growth performance compared to the control group (non-probiotic diet). In terms of non-specific immunity parameters, a significant improvement in O2− production was found in the C2 group, whereas significant improvements in phagocytic activity were found in all the B and C groups. The C2 group displayed optimal O2− production, phagocytic rate, and phagocytic index results. For the challenge test, the C groups showed higher Vibrio resistance than the other experimental groups and the control group. These results suggest that product C, given at dosages of 2 g/kg, may serve as a growth-promoting and immunostimulatory additive for the cultivation of Asian seabass.

Bacteriome Structure, Function, and Probiotics in Fish Larviculture: The Good, the Bad, and the Gaps

Aquaculture is the fastest-growing sector in food production worldwide. For decades, research on animal physiology, nutrition, and behavior established the foundations of best practices in land-based fish rearing and disease control. Current DNA sequencing, bioinformatics, and data science technologies now allow deep investigations of host-associated microbiomes in a tractable fashion. Adequate use of these technologies can illuminate microbiome dynamics and aid the engineering of microbiome-based solutions to disease prevention in an unprecedented manner. This review examines molecular studies of bacterial diversity, function, and host immunitymodulation at early stages of fish development, where microbial infections cause important economic losses. We uncover host colonization and virulence factors within a synthetic assemblage of fish pathogens using high-end comparative genomics and address the use of probiotics and paraprobiotics as applicable disease-prevention strategies in fish larval and juvenile rearing. We finally propose guidelines for future microbiome research of presumed relevance to fish larviculture.

Effects of Paeonol and Gastroretention Tablets of Paeonol on Experimental Gastric Ulcers and Intestinal Flora in Rats

Paeonol, a major ingredient isolated from Moutan Cort, has various pharmacological effects. Our previous studies have shown that paeonol can exert antioxidant and anti-inflammatory therapeutic effects on ethanol-induced experimental gastric ulcer (GU). Therefore, in this study, we designed two GU models in rats induced by pyloric ligation (PL) and acetic acid and evaluated the protective effects of paeonol and gastroretention tablets of paeonol (GRT-Ps; 24, 48, and 96 mg/kg) on GU in rats and the effect of paeonol (48 mg/kg) on the intestinal flora. In vivo experiments showed that paeonol or GRT-Ps remarkably reduced gastric mucosal damage in a dose-dependent manner in the different types of models and improved the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) content. And in fact, the sustained-release effect of GRT-Ps is more conducive to the improvement of GU compared with the rapid clearance of free drugs. In the PL-induced model, gastric secretion parameters, that is, pH and total acid, showed significant differences compared with the model group. In addition, paeonol treatment can improve the richness and diversity of the intestinal flora and increase the amount of beneficial bacteria, such as Lactobacillus. Paeonol and its stable sustained-release tablet GRT-Ps can promote ulcer healing by inhibiting oxidative stress and regulating the intestinal flora. This study can provide basis for the clinical treatment of GU with paeonol. Graphical Abstract.

Comparative evaluation of Lactobacillus strains with different adhesion ability on growth performance and immunomodulatory activity in broiler chickens

The study was designed to assess the effect of 2 Lactobacillus strains (Lactobacillus kefiri 1.3207 and Lactobacillus plantarum 1.2567) with different adherence ability on growth performance and immunomodulatory activity in broiler. The BW and FCR were higher in L. kefiri 1.3207 and L. plantarum 1.2567 groups compared to control group at 42 days of age, and BW of broilers in L. kefiri 1.3207 group was significantly higher than that in L. plantarum 1.2567 group. IgA and IgG contents and the spleen and bursa of Fabricius indices in significantly increased in the L. kefiri 1.3207 group, but not in the L. plantarum 1.2567-treated group. L. kefiri 1.3207 had more significant effect on growth performance, plasma IgA and IgG levels and immune organs indices because it had better adhesion ability.

Effects of dietary b-glucan, mannan oligosaccharide, Lactobacillus plantarum and their combinations on growth performance, immunity and immune related gene expression of Caspian trout, Salmo trutta caspius (Kessler, 1877)

This study investigated the effect of individual and combination of dietary pre- and probiotics (β-glucan, 3 mg/g; mannan oligosaccharide (MOS), 4 mg/g; and Lactobacillus plantarum; 10⁸ CFU/mg diet) on growth performance, blood immune parameters, expression of immune related genes, and intestinal microbial of Caspian trout (Salmo trutta caspius). On the basis of feeding with immunostimulant diets, the fish were assigned into eight groups denoted as: control (basal diet), bβ (basal diet + β-glucan), bM (basal diet + MOS), bLp (basal diet + L. plantarum), bβLp (basal diet + β-glucan + L. plantarum), bMLp (basal diet + MOS + L. plantarum), bMβ (basal diet + MOS + β-glucan), and bMβLp (basal diet + MOS + β-glucan + L. plantarum). All of the immunostimulant diets, in general, reduced feed intake (FI) and food conversion ratio (FCR) and increased WG, PER, and final weight. Condition factor (CF) demonstrated the lowest level in the experimental group received bMβLp. Total lipid increased in the fish received the additives, especially bM and bMβ. Ash content demonstrated significant increase in the fish fed on bβ and bMβLp, whereas moisture content was reduced in the group fed with L. plantarum-supplemented diet. All immunostimulant diets enhanced the activity and levels of lysozyme, Immunoglobulin M (IgM), and serum alternative complement activity (ACH50); the highest value for these indices was observed in the groups fed with bMβ, bMβLp, and bβLp. bMβ-treated fish group displayed the highest cortisol and glucose levels. bM diet induced the highest mRNA transcription of TNF-α1 in head kidney, whereas bLp, bMβ, and bMβLp showed no effect. IL1β exhibited the greatest up-regulation, about 8.75 fold change, in response to the diet supplemented only with β-glucan. bβLp and bβ significantly enhanced the relative IL-8 mRNA expression in the head kidney (about 2.75 and 1.9 folds, respectively), yet in response to bMβLp treatment it showed a decrease of about 5.7 times lower than the control group. In addition, intestinal population of L. plantarum showed the highest loads in the groups fed on the diets which were treated with the probiotic. Taken together, combinational use of these immunostimulants enhanced humoral innate immune system, whereas their individual and combinational application could increase and decrease the transcription of inflammation-related genes, respectively.

Effects of Dietary Lactobacillus plantarum on Growth Performance, Digestive Enzymes and Gut Morphology of Litopenaeus vannamei

A 15-day feeding trial was conducted to investigate the effect of dietary Lactobacillus plantarum on growth performance, digestive enzyme activities and gut morphology of juvenile Pacific white shrimp, Litopenaeus vannamei (initial body weight = 7.96 ± 0.59 g). Four microbound diets were formulated to contain fermentation supernatant (FS), live bacteria (LB), dead bacteria (DB), and cell-free extract (CE) of L. plantarum. Results indicated that final weight was significantly higher in FS, DB, and CE group in comparison to the control group (P < 0.05). The maximum weight gain rate (WGR) and specific growth rate (SGR) of the CE diet group were significantly higher than that of other groups (P < 0.05). The FCR of CE diet group was lower than that of the control, LB, DB, and FS diets groups (P < 0.05). The highest digestive enzyme activities (amylase, lipase, and pepsin activity) in the hepatopancreas and gut of shrimp were observed in the CE diet group. Histological study revealed that dietary CE diet could significantly increase the enterocytes height of shrimp. The administration of cell-free extract of L. plantarum could effectively improve the growth performance of L. vannamei via the improvement of digestive enzyme activities and the enterocytes height of shrimp. The results of this study will be essential to promote application of probiotics in shrimp aquaculture.

Lactic Acid Bacteria in Finfish-An Update

A complex and dynamic community of microorganisms, play important roles within the fish gastrointestinal (GI) tract. Of the bacteria colonizing the GI tract, are lactic acid bacteria (LAB) generally considered as favorable microorganism due to their abilities to stimulating host GI development, digestive function, mucosal tolerance, stimulating immune response, and improved disease resistance. In early finfish studies, were culture-dependent methods used to enumerate bacterial population levels within the GI tract. However, due to limitations by using culture methods, culture-independent techniques have been used during the last decade. These investigations have revealed the presence of Lactobacillus, Lactococcus, Leuconostoc, Enterococcus, Streptococcus, Carnobacterium, Weissella, and Pediococcus as indigenous species. Numerous strains of LAB isolated from finfish are able to produce antibacterial substances toward different potential fish pathogenic bacteria as well as human pathogens. LAB are revealed be the most promising bacterial genera as probiotic in aquaculture. During the decade numerous investigations are performed on evaluation of probiotic properties of different genus and species of LAB. Except limited contradictory reports, most of administered strains displayed beneficial effects on both, growth-and reproductive performance, immune responses and disease resistance of finfish. This eventually led to industrial scale up and introduction LAB-based commercial probiotics. Pathogenic LAB belonging to the genera Streptococcus, Enterococcus, Lactobacillus, Carnobacterium, and Lactococcus have been detected from ascites, kidney, liver, heart, and spleen of several finfish species. These pathogenic bacteria will be addressed in present review which includes their impacts on finfish aquaculture, possible routes for treatment. Finfish share many common structures and functions of the immune system with warm-blooded animals, although apparent differences exist. This similarity in the immune system may result in many shared LAB effects between finfish and land animals. LAB-fed fish show an increase in innate immune activities leading to disease resistances: neutrophil activity, lysozyme secretion, phagocytosis, and production of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α). However, some LAB strains preferentially induces IL-10 instead, a potent anti-inflammatory cytokine. These results indicate that LAB may vary in their immunological effects depending on the species and hosts. So far, the immunological studies using LAB have been focused on their effects on innate immunity. However, these studies need to be further extended by investigating their involvement in the modulation of adaptive immunity. The present review paper focuses on recent findings in the field of isolation and detection of LAB, their administration as probiotic in aquaculture and their interaction with fish immune responses. Furthermore, the mode of action of probiotics on finfish are discussed.

Effects of dietary Lactobacillus plantarum in different treatments on growth performance and immune gene expression of white shrimp Litopenaeus vannamei under normal condition and stress of acute low salinity

A 45-day feeding trial followed by an acute stress test of low salinity was done to evaluate effects of Lactobacillus plantarum on growth performance and anti-stress capability of white shrimp (Litopenaeus vannamei). Shrimp were randomly allocated in 15 tanks (100 shrimp per tank) and divided into 5 treatments with 3 replicates. Triplicate tanks were fed with a control diet or diets containing different treatments of L. plantarum (fermentation supernatant (FS), live bacteria (LB), dead bacteria (DB) and cell-free extract (CE) of L. plantarum) as treatment groups. Growth performance including weight gain (WGR), feed conversion ratio (FCR) and specific growth rate (SGR) were determined after feeding 45 days. Anti-stress capacity was evaluated by determining the gene expression of ProPO, SOD and Lys in gut of shrimp at the end of feeding trial and again at 96 h post-stress test. Results indicated that supplementation of L. plantarum into diet had significantly improved growth performance of L. vannamei. On the other hand, L. plantarum supplementation had no significant effects on the gene expression of SOD and Lys in gut of shrimp cultured under normal condition for 45 days. Supplementation of L. plantarum had increased survivability of L. vannamei having higher survival rates compared to the control group. However, statistical analysis showed no significant difference between the control group and treatments. Compared with the control group, supplementation of L. plantarum significantly improved the resistance of L. vannamei against the stress of acute low salinity, as indicated by higher survival rate as well as higher transcript levels of ProPo, SOD and Lys gene. Our findings suggested that L. plantarum, especially cell-free extract of L. plantarum has improved the anti-stress capacity of L. vannamei and could serve as a potential feed additive that helps shrimp to overcome environmental stresses.