Effects of single or conjoint administration of lactic acid bacteria as potential probiotics on growth, immune response and disease resistance of snakehead fish (Channa argus)

Dietary kelp meal improves serum antioxidants, intestinal immunity, and lipid metabolism in hybrid snakehead (Channa maculata ♀ × Channa argus ♂)

BACKGROUND

Dietary kelp possesses a variety of useful biological qualities but does not have a toxic effect on the host. In this study, we examine how kelp dietary supplementation enhances the serum biochemistry, intestinal immunity, and metabolism of hybrid snakehead. A total of 810 juvenile hybrid snakeheads (Channa maculata ♀ × Channa argus ♂), with an initial average weight of 11.4 ± 0.15 g, were allocated randomly to three treatment groups (three replicates per group). The fish were fed for 60 days with isonitrogenous and isolipidic diets. The groups were the control group (C) (20% high-gluten flour), the medium replacement group (MR) (10% high-gluten flour and 10% kelp meal), and the full replacement group (FR) (0% high-gluten flour and 15% kelp meal).

RESULTS

The results showed that dietary kelp increased the activity of serum antioxidant enzymes significantly and decreased the content of serum malondialdehyde (MDA) in hybrid snakeheads, with significant changes in the FR group (P < 0.05). The intestinal morphology results showed that dietary kelp helped to increase the specific surface area of intestinal villi, which was beneficial for intestinal digestion and absorption. According to transcriptome and quantitative real-time polymerase chain reaction (qRT-PCR) analysis, dietary kelp can improve the expression of intestinal immunity and metabolism-related pathways. Among them, immune-related genes MHC1 and HSPA1 were significantly up-regulated, and IGH, MHC2, and IL-8 were significantly down-regulated (P < 0.05). Lipid metabolism-related genes DGAT2, FABP2, RXRα, and PLPP1 were all significantly up-regulated (P < 0.05).

CONCLUSION

Dietary kelp can effectively improve the antioxidant function of hybrid snakeheads, improve intestinal morphology, reduce intestinal inflammation, and promote intestinal lipid synthesis and transportation, thereby improving intestinal immunity and metabolic functions. © 2024 Society of Chemical Industry.

Sulfamethoxazole stress endangers the gut health of sea cucumber (Apostichopus japonicus) and affects host metabolism

Sulfamethoxazole (SMZ) is a frequently detected antibiotic in the environment, and there is a growing concern about its potential toxic effects on aquatic organisms. sea cucumber (Apostichopus japonicas) is a benthic invertebrate whose gut acts as a primary immune defense and serves critical protective barrier. In this study, growth performance, histology, gut microbiota, and metabolomics analyses were performed to investigate the toxic response in the intestine of sea cucumber effects caused by SMZ stress for 56 d by evaluating with different concentrations of SMZ (0, 1.2×10-3, and 1.2 mg/L). The weight gain rate of sea cucumbers under SMZ stress showed significant decrease, indicating that the growth of sea cucumbers was hindered. Analysis of the intestinal morphological features indicated that SMZ stimulation resulted in atrophy of the sea cucumber gut. In the 1.2×10-3 mg/L concentration, the thickness of muscle and mucosal layers was reduced by 12.40% and 21.39%, while in the 1.2 mg/L concentration, the reductions were 35.08% and 26.98%. The abundance and diversity of sea cucumber intestinal bacteria decreased significantly (P < 0.05) under the influence of SMZ. Notably, the intestinal bacteria of sea cucumber became homogenized with the increase in SMZ concentration, and the relative abundance of Ralstonia reached 81.64% under the stress of 1.2 mg/L concentration. The SMZ stress significantly impacted host metabolism and disrupted balance, particularly in L-threonine, L-tyrosine, neuronic acid, piperine, and docosapentaenoic acid. SMZ leads to dysregulation of metabolites, resulting in growth inhibition and potential inflammatory responses that could adversely affect the normal activities of aquatic organisms. Further metabolic pathway enrichment analyses demonstrated that impaired biosynthesis of unsaturated fatty acids and aminoacyl-tRNA biosynthesis metabolic pathway were major reasons for SMZ stress-induced intestinal bacteria dysbiosis. This research aims to provide some theoretical evidence for the ecological hazard assessment of antibiotics in water.

Effects of Enterococcus faecium (R8a) on nonspecific immune gene expression, immunity and intestinal flora of giant tiger shrimp (Penaeus monodon)

In this study, Penaeus monodon were gave basic feed supplemented with three levels of Enterococcus faecium. Then, the expression of non-specific immunity-related genes, and the activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), malondialdehyde (MDA), acid phosphatase (ACP), alkaline phosphatase (AKP), phenol oxidase (PO) were evaluated. Meanwhile, the disease resistance test and intestinal flora determination were conducted. The results showed that the MDA levels of 2% and 5% E. faecium groups were significantly lower than that of the control group (P < 0.05). While the SOD and T-AOC and ACP and AKP of experimental groups were significantly higher (P < 0.05), the PO of experimental groups were significantly lower than that of the control group (P < 0.05). In addition, the expressions of immunity-related genes (tlr22, dorsal, lysozyme, crustin, imd, and relish) in the 2% and 5% E. faecalis groups were significantly greater than those in the control group (P < 0.05). After P. monodon was challenged with Vibrio parahaemolyticus for 7 days, the average cumulative mortality of P. monodon in the 2% and 5% groups were significantly lower than that in the 0% group (P < 0.05). With the increase of feeding time, the number of effective OTUs in each group showed a downward trend. At the 14th d, Proteobacteria, Bacteroidetes and Firmicutes, the dominant flora in the intestinal tract of P. monodon. In summary, supplied with E. faecium could increase the expression of non-specific immunity-related genes, enhance the immune capacity of P. monodon.

Synbiotic Agents and Their Active Components for Sustainable Aquaculture: Concepts, Action Mechanisms, and Applications

Aquaculture is a fast-emerging food-producing sector in which fishery production plays an imperative socio-economic role, providing ample resources and tremendous potential worldwide. However, aquatic animals are exposed to the deterioration of the ecological environment and infection outbreaks, which represent significant issues nowadays. One of the reasons for these threats is the excessive use of antibiotics and synthetic drugs that have harmful impacts on the aquatic atmosphere. It is not surprising that functional and nature-based feed ingredients such as probiotics, prebiotics, postbiotics, and synbiotics have been developed as natural alternatives to sustain a healthy microbial environment in aquaculture. These functional feed additives possess several beneficial characteristics, including gut microbiota modulation, immune response reinforcement, resistance to pathogenic organisms, improved growth performance, and enhanced feed utilization in aquatic animals. Nevertheless, their mechanisms in modulating the immune system and gut microbiota in aquatic animals are largely unclear. This review discusses basic and current research advancements to fill research gaps and promote effective and healthy aquaculture production.

α-lipoic acid ameliorates hepatotoxicity induced by chronic ammonia toxicity in crucian carp (Carassius auratus gibelio) by alleviating oxidative stress, inflammation and inhibiting ERS pathway

High environment ammonia (HEA) poses a deadly threat to aquatic animals and indirectly impacts human healthy life, while nutritional regulation can alleviate chronic ammonia toxicity. α-lipoic acid exhibits antioxidative effects in both aqueous and lipid environments, mitigating cellular and tissue damage caused by oxidative stress by aiding in the neutralization of free radicals (reactive oxygen species). Hence, investigating its potential as an effective antioxidant and its protective mechanisms against chronic ammonia stress in crucian carp is highly valuable. Experimental fish (initial weight 20.47 ± 1.68 g) were fed diets supplemented with or without 0.1% α-lipoic acid followed by a chronic ammonia exposure (10 mg/L) for 42 days. The results revealed that chronic ammonia stress affected growth (weight gain rate, specific growth rate, and feed conversion rate), leading to oxidative stress (decreased the activities of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase; decreased total antioxidant capacity), increased lipid peroxidation (accumulation of malondialdehyde), immune suppression (decreased contents of nonspecific immune enzymes AKP and ACP, 50% hemolytic complement, and decrease of immunoglobulin M), impaired ammonia metabolism (reduced contents of Glu, GS, GSH, and Gln), imbalance of expression of induced antioxidant-related genes (downregulation of Cu/Zu SOD, CAT, Nrf2, and HO-1; upregulation of GST and Keap1), induction of pro-apoptotic molecules (transcription of BAX, Caspase3, and Caspase9), downregulation of anti-apoptotic gene Bcl-2 expression, and induction of endoplasmic reticulum stress (upregulation of IRE1, PERK, and ATF6 expression). The results suggested that the supplementation of α-lipoic acid could effectively induce humoral immunity, alleviate oxidative stress injury and endoplasmic reticulum stress, and ultimately alleviate liver injury induced by ammonia poisoning (50-60% reduction). This provides theoretical basis for revealing the toxicity of long-term ammonia stress and provides new insights into the anti-ammonia toxicity mechanism of α-lipoic acid.

The Mechanisms of Polysaccharides from Tonic Chinese Herbal Medicine on the Enhancement Immune Function: A Review

Tonic Chinese herbal medicine is a type of traditional Chinese medicine, and its primary function is to restore the body's lost nutrients, improve activity levels, increase disease resistance, and alleviate physical exhaustion. The body's immunity can be strengthened by its polysaccharide components, which also have a potent immune-system-protecting effect. Several studies have demonstrated that tonic Chinese herbal medicine polysaccharides can improve the body's immune response to tumor cells, viruses, bacteria, and other harmful substances. However, the regulatory mechanisms by which various polysaccharides used in tonic Chinese herbal medicine enhance immune function vary. This study examines the regulatory effects of different tonic Chinese herbal medicine polysaccharides on immune organs, immune cells, and immune-related cytokines. It explores the immune response mechanism to understand the similarities and differences in the effects of tonic Chinese herbal medicine polysaccharides on immune function and to lay the foundation for the future development of tonic Chinese herbal medicine polysaccharide products.

Lactococcus lactis, a bacterium with probiotic functions and pathogenicity

Lactococcus lactis (L. lactis) is the primary organism for lactic acid bacteria (LAB) and is a globally recognized safe microorganism for the regulation of the intestinal micro-ecological balance of animals and improving the immune performance of the host. L. lactis is known to play a commercially important role in feed fortification, milk fermentation, and vaccine production, but pathogenic L. lactis has been isolated from many clinical cases in recent years, such as the brain of silver carp with Lactococcosis, the liver and spleen of diseased waterfowl, milk samples and padding materials with cow mastitis, and blood and urine from human patients with endocarditis. In dairy farming, where L. lactis has been used as a probiotic in the past, however, some studies have found that L. lactis can cause mastitis in cows, but the lack of understanding of the pathogenesis of mastitis in cows caused by L. lactis has become a new problem. The main objective of this review is to analyze the increasingly serious clinical mastitis caused by L. lactis and combined with the wide application of L. lactis as probiotics, to comprehensively discuss the characteristics and diversity of L. lactis.

Bacterial diseases in marine fish species: current trends and future prospects in disease management

The fisheries sub-sector of aquaculture-i.e., the pisciculture industry, contributes significantly to a country's economy, employing a sizable proportion of the population. It also makes important contributions to household food security because the current demand for animal protein cannot be fulfilled by harvesting wild fish from riverines, lakes, dams, and oceans. For good pond management techniques and sustaining fish health, the fisherfolk, and the industry require well-established regulatory structures, efficient disease management strategies, and other extended services. In rearing marine fish, infections resulting from disease outbreaks are a weighty concern because they can cause considerable economic loss due to morbidity and mortality. Consequently, to find effective solutions for the prevention and control of the major diseases limiting fish production in aquaculture, multidisciplinary studies on the traits of potential fish pathogens, the biology of the fish as hosts, and an adequate understanding of the global environmental factors are fundamental. This review highlights the various bacterial diseases and their causative pathogens prevalent in the pisciculture industry and the current solutions while emphasising marine fish species. Given that preexisting methods are known to have several disadvantages, other sustainable alternatives like antimicrobial peptides, synthetic peptides, probiotics, and medicinal treatments have emerged to be an enormous potential solution to these challenges.

Evaluation of dietary single probiotic isolates and probiotic multistrain consortia in growth performance, gut histology, gut microbiota, immune regulation, and infection resistance of Nile tilapia, Oreochromis niloticus, shows superior monostrain performance

The probiotic potential of a designed bacterial consortia isolated from a competitive exclusion culture originally obtained from the intestinal contents of tilapia juveniles were evaluated on Nile tilapia alevins. The growth performance, intestinal histology, microbiota effects, resistance to Streptococcus agalactiae challenge, and immune response were assessed. In addition, the following treatments were included in a commercial feed: A12+M4+M10 (Lactococcus lactis A12, Priestia megaterium M4, and Priestia sp. M10), M4+M10 (P. megaterium M4, and Priestia sp. M10) and the single bacteria as controls; A12 (L. lactis A12), M4 (P. megaterium M4), M10 (Priestia sp. M10), also a commercial feed without any probiotic addition was included as a control. The results showed that all probiotic treatments improved the growth performance, intestinal histology, and resistance during experimental infection with S. agalactiae in comparison to the control fish. Also, the administration of probiotics resulted in the modulation of genes associated with the innate and adaptive immune systems that were non-dependent on microbial colonization. Surprisingly, L. lactis A12 alone induced benefits in fish compared to the microbial consortia, showing the highest increase in growth rate, survival during experimental infection with S. agalactiae, increased intestinal fold length, and the number of differentially expressed genes. Lastly, we conclude that a competitive exclusion culture is a reliable source of probiotics, and monostrain L. lactis A12 has comparable or even greater probiotic potential than the bacterial consortia.

The molecular mechanisms of alpha-lipoic acid on ameliorating aflatoxin B1-induced liver toxicity and physiological dysfunction in northern snakehead (Channa argus)

This research aimed to evaluate the protective mechanism of alpha-lipoic acid (α-LA) on the food-borne aflatoxin B₁ (AFB₁) exposure-induced liver toxicity and physiological dysfunction in the northern snakehead (Channa argus). 480 fish (9.24±0.01 g) were randomly assigned to four treatment groups and fed with four experimental diets for 56 d including the control group (CON), AFB₁ group (200 ppb AFB₁), 600 α-LA group (600 ppm α-LA+200 ppb AFB₁), and 900 α-LA group (900 ppm α-LA+200 ppb AFB₁). The results revealed that 600 and 900 ppm α-LA attenuated AFB₁-induced growth inhibition and immunosuppression in northern snakehead. 600 ppm α-LA significantly decreased the serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase levels, and AFB₁ bioaccumulation, and attenuated the changes of hepatic histopathological and ultrastructure induced by AFB₁. Moreover, 600 and 900 ppm α-LA significantly up-regulated phase I metabolism genes (cytochrome P450-1a, 1b, and 3a) mRNA expression, inhibited the levels of malondialdehyde, 8‑hydroxy-2 deoxyguanosine and reactive oxygen species in the liver. Notably, 600 ppm α-LA significantly up-regulated the expression levels of nuclear factor E2 related factor 2 and its related downstream antioxidant molecules (heme oxygenase 1 and NAD(P)H: quinone oxidoreductase 1, etc.), increased the phase II detoxification enzyme-related molecules (glutathione-S-transferase and glutathione), antioxidant parameters (catalase and superoxide dismutase, etc.), and the expressions of Nrf2 and Ho-1 protein in the presence of AFB₁ exposure. Furthermore, 600 and 900 ppm α-LA significantly reduced the characteristic indices of AFB₁-induced endoplasmic reticulum stress (glucose-regulated protein 78 and inositol requiring enzyme 1, etc.), apoptosis (caspase-3 and cytochrome c, etc.) and inflammation (nuclear factor kappa B and tumor necrosis factor α, etc.), while increased the B-cell lymphoma-2 and inhibitor of κBα in the liver after being exposed to AFB₁. To summarize, the above results indicate that dietary α-LA could modulate the Nrf2 signaling pathway to ameliorate AFB₁-induced growth inhibition, liver toxicity, and physiological dysfunction in northern snakehead. Although the concentration of α-LA increased to 900 ppm from 600 ppm, the protective effects of the 900 ppm α-LA do not show an advantage over the 600 ppm α-LA, and even show inferiority in some respects. So that the recommended concentration of α-LA is 600 ppm. The present study provides the theoretical foundation for developing α-LA as the prevention and treatment of AFB₁-induced liver toxicity in aquatic animals.

Effects of two host-associated probiotics Bacillus mojavensis B191 and Bacillus subtilis MRS11 on growth performance, intestinal morphology, expression of immune-related genes and disease resistance of Nile tilapia (Oreochromis niloticus) against Streptococcusiniae

The intensification and diversification of production systems have increased the incidence of diseases, which are usually treated with antibiotics. However, its use should be restricted due to the increasing prevalence of antibiotic-resistant bacteria. Probiotics represent therefore an alternative environmentally friendly strategy for improving growth and disease resistance in aquaculture. Considering that host-derived probiotics may offer greater advantages than those from other environments in terms of safety and efficacy, two potential host-associated probiotic strains (Bacillus mojavensis B191 and Bacillus subtilis MRS11) were used in the present study, which were previously isolated from intestinal mucus of Nile tilapia (Oreochromis niloticus). This study was conducted to assess the effects of dietary administration of two Bacillus strains on growth performance, intestinal morphology, immunity, and disease resistance of Nile tilapia. A total of 375 fish were randomly divided into five groups in triplicate. Nile tilapia were fed a basal diet (control group) or a basal diet supplemented with Bacillus mojavensis B191 (BM) or Bacillus subtilis MRS11 (BS) spores at different concentrations of 1 × 10⁶ (BM6 and BS6, respectively) and 1 × 10⁸ (BM8 and BS8, respectively) CFU/g of feed for 60 days. Moreover, the survival rate of tilapia upon challenge with Streptococcus iniae was determined following the feeding trial. After the feeding trial, the growth performances were significantly improved in all probiotic-fed groups, with the BS8 group being the highest. Light and electron microscopy observations revealed elevated goblet cells, intestinal villus length (except BM8), microvilli length, microvilli density, and perimeter ratio increase in the intestine of all probiotic-fed groups compared with the control group. Regarding the expression analysis, HSP70 gene was only up-regulated in the BM8 group and a general trend of up-regulation of some immune-related cytokines (TGF-β, IL-10, TNF-α and IL-1β) was observed in all probiotic-fed groups. Likewise, the best protection against Streptococcus iniae was observed in the BS8 group, followed by BS6, BM6 and BM8 groups. Altogether, dietary probiotic supplementation with BS8 and BM6 may improve growth performance, intestinal morphology, immunity, and disease resistance in Nile tilapia.

Dietary supplementation of probiotics fermented Chinese herbal medicine Sanguisorba officinalis cultures enhanced immune response and disease resistance of crucian carp (Carassius auratus) against Aeromonas hydrophila

Aeromonas hydrophila, a Gram-negative bacterium, is one of the major pathogens causing bacterial sepsis in aquatic animals due to drug resistance and pathogenicity, which could cause high mortality and serious economic losses to the aquaculture. Sanguisorba officinalis (called DiYu in Chinese, DY) is well known as herbal medicine, which could inhibit the growth of pathogenic bacteria, hemostasis and regulate the immune response. Moreover, the active ingredients in DY could remarkably reduce drug resistance. In this study, we investigated the effects of probiotic fermentation cultures on A. hydrophila through in vitro and in vivo experiments. Three lactic acid bacteria, including Lactobacillus rhamnosus (LGG), Lactobacillus casei (LC) and Lactobacillus plantarum (LP), were selected to ferment the Chinese herbal medicine DY. The assays of antagonism showed that all three fermented cultures could influence the ability of A. hydrophila growth, among which L. rhamnosus fermented DY cultures appeared to be the strongest inhibitory effect. In addition, the biofilm determination revealed that L. rhamnosus fermented DY cultures could significantly inhibit the biofilm formation of A. hydrophila compared to the other groups. Furthermore, protease, lecithinase and urease activities were found in the three fermentation cultures. Three probiotics fermented DY cultures were orally administration with crucian carp to evaluate the growth performance, immunological parameters and pathogen resistance. The results showed that the three fermentation cultures could promote the growth performance of crucian carp, and the immunoglobulins, antioxidant-related enzymes and immune-related genes were significantly enhanced. Besides, the results showed that crucian carp received L. rhamnosus (60.87%), L. casei (56.09%) and L. plantarum (41.46%) fermented DY cultures had higher survival rates compared with the control group after infection with A. hydrophila. Meanwhile, the pathological tissue results revealed that the probiotic fermented cultures could largely improve the tissues damage caused by the pathogenic bacteria. In conclusion, this study proved that the fermentation cultures of three probiotics could effectively inhibit the growth of A. hydrophila, regulate the level of immune response and improve the survival rate against A. hydrophila in crucian carp. The present data suggest that probiotic fermented Sanguisorba officinalis act as a potential gut-targeted therapy regimens to protecting fish from pathogenic bacteria infection.

Dietary aflatoxin B1 caused the growth inhibition, and activated oxidative stress and endoplasmic reticulum stress pathway, inducing apoptosis and inflammation in the liver of northern snakehead (Channa argus)

The purpose of this study was to investigate the effects of dietary aflatoxin B₁ (AFB₁) on growth performance and AFB₁ biotransformation, and hepatic oxidative stress, endoplasmic reticulum (ER) stress, apoptosis, and inflammation in northern snakehead (Channa argus). A total of 600 northern snakeheads (7.52 ± 0.02 g) were divided into five groups (three replicates/group) and fed the diets with AFB₁ at concentrations of 0, 50, 100, 200, and 400 ppb for 8 weeks. The results demonstrated that dietary AFB₁ (≥ 200 ppb) reduced FBW, WG, and SGR. 100, 200, and 400 ppb AFB₁ treatment groups significantly decreased the PER, CRP, C3, C4, IgM, and LYS levels in northern snakehead, while FCR was significant increased. Moreover, dietary AFB₁ (100, 200, and 400 ppb) increased cyp1a, cyp1b (except 400 ppb), and cyp3a mRNA expression levels, while reducing the GST enzymatic activity and mRNA expression levels in northern snakehead. Furthermore, AFB₁ (≥ 100 ppb) increased ROS, MDA, and 8-OHdG levels, and grp78, ire1, perk, jnk, chop, and traf2 mRNA expression levels, and decreased SOD, CAT, GSH-Px, and GSH (except 100 ppb) levels and the gene expression levels of cat, gsh-px (except 100 ppb), and Cu/Zn sod. In addition, AFB₁ (100, 200, and 400 ppb) up-regulated the cyt-c, bax, cas-3, and cas-9 mRNA levels in the liver, while down-regulating the bcl-2 expression levels. Meanwhile, the expression levels of nf-κb, tnf-α (except 100 ppb), il-1β, and il-8 in the liver were up-regulated in AFB₁ treatment groups (≥ 100 ppb), while the iκbα mRNA levels were down-regulated. In summary, dietary AFB₁ reduced growth performance and humoral immunity in northern snakehead. Meanwhile, the cyclic occurrence of oxidative stress and ER stress, and induced apoptosis and inflammation, is one of the main reasons for AFB₁-induced liver injury in the northern snakehead, which will provide valuable information and a fresh perspective for further research into AFB₁-induced liver injury in fish.

The effects of dietary supplementation of ginseng stem and leaf saponins on the antioxidant capacity, immune response, and disease resistance of crucian carp, Carassius auratus

This is the first study to explore the positive effects of ginseng stem and leaf saponins (GSLS) on antioxidant capability, immunity, and disease resistance of crucian carp. Seven hundred fifty crucian carps (initial body weight: 25 ± 0.15 g (mean ± SE)) were randomly allocated into five groups with three replicates each; five diets supplemented with the final concentration of 0, 1, 2, 4, and 8 g/kg GSLS were fed to crucian carp for 5 weeks. The results demonstrated that, at a concentration of 8 g/kg, the contents of IgM, C4, SOD, GSH-Px, and the activity of AKP in serum of crucian carp gradually increased at 7, 14, 21, 28, and 35 days, and the expression of immune-relative cytokine genes (TNF-α, IL-10, IFN-γ) in the liver, spleen, and the intestinal tract also had a significant up-regulation (P < 0.05), and which were significant difference compared with control (P < 0.05). The above results demonstrated that dietary GSLS showed enhancement effects on the antioxidant and anti-inflammatory capability, and innate immune response of crucian carp. The feed of 8 g/kg GSLS for 1 week could improve the survival rate 44% more than the control group when crucian carp infected Aeromonas hydrophila (A. hydrophila). In conclusion, the addition of GSLS at a concentration of 8 g/kg in the diet improve immune-related enzyme activity better, immune-relative cytokine expression, and disease resistance.

A mini-review on co-supplementation of probiotics and medicinal herbs: Application in aquaculture

The aquaculture industry is geared toward intensification and successfully meets half of the world's demand for fish protein. The intensive farming system exposes the animal to the risk of disease outbreaks, which has economic consequences. Antibiotics are commonly used for the health management of aquaculture species. However, this has several drawbacks, including the increase in antibiotic resistance in pathogenic bacteria and the entry of antibiotic residues into the human food chain, which is a public health and environmental concern. The potential of probiotics, prebiotics, synbiotics, and medicinal herbs as alternatives to antibiotics for the health management of aquaculture species has been investigated in numerous studies. This review discusses the potential use of combinations of probiotics and medicinal herbs as prophylactic agents in aquaculture, along with the definitions, sources, and modes of action. The positive aspects of combining probiotics and medicinal herbs on growth performance, the immune system, and disease resistance of aquaculture species are also highlighted. Overall, this review addresses the potential of combinations of probiotics and medicinal herbs as feed additives for aquaculture species and the key role of these feed additives in improving the welfare of aquaculture species.

The dietary mixture of betaine, lactic acid bacteria, and exogenous digestive enzymes enhanced the growth performance, intestinal health, and immunity of Nile tilapia (Oreochromis niloticus) grown in outdoor concrete tanks

It has been illustrated that using mixtures of feed additives is more efficient than using individual additives in aquaculture. Hence, this study aimed to study a dietary mixture of betaine, lactic acid bacteria, and exogenous digestive enzymes (BLE) on the growth performance, digestion capacity, intestinal health, and blood indices of Nile tilapia reared outdoors in concrete tanks. Five diets were prepared where the basal diets mixed with BLE at 0, 0.25, 0.5, 0.75, and 1%. After 90 days, the growth performance of Nile tilapia-fed BLE was markedly enhanced in fish fed 0.25 and 0.5% of BLE, while the feed conversion ratio (FCR) was reduced (P<0.05). The lipase activity was significantly higher in tilapia fed BLE at 0.25, 0.5, and 0.75% than 0 and 1%. The amylase activity was meaningfully increased by 0.5% of BLE than 0, 0.25, 0.75, and 1%. The protease activity was significantly higher in tilapia fed BLE at 0.25 and 0.5 than 0, 0.75, and 1% (P<0.05). The intestine of fish fed on BLE showed an increase in intestinal villi density. The villi length, width, and the number of goblet cells were markedly higher in the anterior, middle, and posterior segments of the intestines of tilapia fed BLE than in the control group (P<0.05). Further, fish fed BLE had higher intestinal morphometry indices and count of goblet cells than the control. Significantly fish fed 0.25, and 0.5% of BLE had higher hemoglobulin, and hematocrit levels than fish fed 0, 0.75, and 1%. While, fish fed 0.5% had higher red blood cells than fish fed the remaining BLE levels (P<0.05). On the other hand, no marked effects for BLE supplementation were seen on the alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein, albumin, globulin, creatinine, uric acid, and urea. The regression analysis showed that the maximum dose of BLE supplementation to achieve the highest final weight and the lowest FCR is 0.46% and 0.42%, respectively.

Dietary α-lipoic acid alleviates deltamethrin-induced immunosuppression and oxidative stress in northern snakehead (Channa argus) via Nrf2/NF-κB signaling pathway

The goal of the study was to determine the ameliorative effects of dietary alpha-lipoic acid (α-LA) on deltamethrin (DEL)-induced immunosuppression and oxidative stress in northern snakehead (Channa argus). The northern snakeheads (15.38 ± 0.09 g) were exposed to DEL (0.242 μg/L) and fed with diets supplemented α-LA at 300, 600, and 900 mg/kg. After the 28-day exposure test, we obtained the following results: i) α-LA alleviates DEL-induced liver injury by reversing the increase of the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and liver cytochrome P450 enzymes (Cytochrome P450 (cyp)1a and cyp1b) expression levels. ii) α-LA can reverse the DEL-induced reduction of serum complement 4 (C4), C3, immunoglobulin M (IgM), and lysozyme (LYS) levels and the increase of liver and intestine nuclear factor kappa B (nf-κb) p65, tumor necrosis factor (tnf)-α, interleukin (il)-1β, il-8, and il-6 gene expressions, while il-10 expression levels showed the opposite result. iii) α-LA reversed the reduction of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px) levels in the liver and intestine induced by DEL, while malondialdehyde (MDA) showed the opposite result. iv) α-LA reversed the reduction of Cu/Zn sod, nuclear factor erythroid 2-related factor 2 (nrf2), NAD (P)H: quinone oxidoreductase (nqo)1, and heme oxygenase (ho)-1 antioxidant gene expression levels in the liver and intestine induced by DEL. Therefore, our study indicated that optimal α-LA (600 mg/kg) could attenuate DEL-induced toxicity (including liver damage, immunotoxicity, and oxidative stress) in northern snakehead via Nrf2/NF-κB signaling pathway. This is the first research that explores the alleviated effects of α-LA on DEL-induced toxicity damage in fish. This study provides a positive measure to reduce the toxicity damage caused by DEL to aquatic animals, and provides a theoretical basis for exploring the regulation mechanism of α-LA in toxic substances.

The effects of dietary supplementation of α-lipoic acid on the growth performance, antioxidant capacity, immune response, and disease resistance of northern snakehead, Channa argus

The study was the first time to explore the positive effects of α-LA on growth performance, antioxidant capability, immunity, and disease resistance of northern snakehead (Channa argus). Five hundred and forty northern snakehead fish (initial body weight: 8.74 ± 0.12 g (mean ± SE)) were randomly allocated into six groups with three replicates each. Six diets supplemented with α-LA at doses of 0 (CON), 300 (LA300), 600 (LA600), 900 (LA900), 1200 (LA1200), and 1500 (LA1500) mg/kg were fed to northern snakehead for 8 weeks. The results demonstrated that, when compared with the control group, optimal dietary α-LA increased the weight gain (WG), protein efficiency ratio (PER), and specific growth rate (SGR) and reduced the feed conversion ratio (FCR) of the fish (P < 0.05). Also, optimal dietary α-LA enhanced the immune-related parameters and antioxidant enzyme parameters levels in the head kidney, spleen, and liver of northern snakehead (P < 0.05). Dietary α-LA upregulated the mRNA expression levels of anti-inflammatory cytokines (il10 and tgfβ) and antioxidant related genes (gst, gsh-px, gr and Cu/Zn sod), down-regulated the pro-inflammatory cytokines (il1β, il8, il12 and tnfα) mRNA levels in the liver, spleen and head kidney of the northern snakehead (P < 0.05). The above results demonstrated that optimal dietary α-LA showed enhancement effects on the growth, antioxidant and anti-inflammatory capability, and immune response of northern snakehead. The survival rates in all α-LA treatments were significantly raised after the challenge with Aeromonas veronii (P < 0.05). Based on the quadratic regression analysis of WG, GSH-Px, LYS, and il1β, the optimal dietary α-LA levels were estimated to be 737.0, 775.0, 890.0, and 916.7 mg/kg, respectively. Considering the overall responses in growth performance, antioxidant status, immune response, and inflammatory factors, the recommended dose of α-LA in the diet of fish is 737.0-916.7 mg/kg.

Whole genome sequencing for the risk assessment of probiotic lactic acid bacteria

Probiotic bacteria exhibit beneficial effects on human and/or animal health, and have been widely used in foods and fermented products for decades. Most probiotics consist of lactic acid bacteria (LAB), which are used in the production of various food products but have also been shown to have the ability to prevent certain diseases. With the expansion of applications for probiotic LAB, there is an increasing concern with regard to safety, as cases with adverse effects, i.e., severe infections, transfer of antimicrobial resistance genes, etc., can occur. Currently, in vitro assays remain the primary way to assess the properties of LAB. However, such methodologies are not meeting the needs of strain risk assessment on a high-throughput scale, in the context of the evolving concept of food safety. Analyzing the complete genetic information, including potential virulence genes and other determinants with a negative impact on health, allows for assessing the safe use of the product, for which whole-genome sequencing (WGS) of individual LAB strains can be employed. Genomic data can also be used to understand subtle differences in the strain level important for beneficial effects, or protect patents. Here, we propose that WGS-based bioinformatics analyses are an ideal and cost-effective approach for the initial in silico microbial risk evaluation, while the technique may also increase our understanding of LAB strains for food safety and probiotic property evaluation.

Boosted growth performance, immunity, antioxidant capacity and disease resistance of crucian carp (Carassius auratus) by single or in combination dietary Bacillus subtilis and xylo-oligosaccharides

In this study, a total of 420 healthy crucian carp (9.77 ± 0.04 g) were randomly divided into CK, B·S, XOS and B·S + XOS group, and cultured for 8 weeks. Results showed that the dietary Bacillus subtilis (B. subtilis) and xylo-oligosaccharides (XOS) can significantly increased the final weight, weight gain, specific growth rate, feed efficiency, protein efficiency and survival rate of crucian carp. Dietary B. subtilis and XOS can significantly increased the activities of catalase, glutathione, superoxide dismutase and total antioxidant capacity, significantly decreased the contents of malondialdehyde, and significantly increased the activities of alkaline phosphatase, acid phosphatase, lysozyme and the contents of complement component 3,4 and immunoglobulin M in crucian carp serum. In addition, compared with CK group, the expression levels of TGF-β and IL-10 in B·S, XOS and B·S + XOS group were significantly increased, and the expression levels of TNF-α, HSP90, IL-1β, TLR4 and MyD88 were significantly decreased. Supplementation of B. subtilis and XOS can also improve the intestinal tissue morphology of crucian carp. After injection of 1 × 10⁷ CFU/mL Aeromonas hydrophila (A. hydrophila), compared with CK group, the survival rates of the B·S group, the XOS group and the B·S + XOS group were increased by 13.98%, 10.56% and 30.74%, respectively. These results show that dietary B. subtilis and XOS can significantly improve the growth performance, antioxidant capacity, immunity and resistance to A. hydrophila of crucian carp, and the combined effect is better than that of single addition.

The effect of adding Bacillus amyloliquefaciens LSG2-8 in diets on the growth, immune function, antioxidant capacity, and disease resistance of Rhynchocypris lagowskii

The purpose of this study was to investigate the effect of Bacillus amyloliquefaciens LSG2-8 on the growth performance, immune function, antioxidant capacity, and disease resistance of Rhynchocypris lagowskii. Fish were fed with the feed containing five levels such as 0, 1.0 × 10⁶, 1.0 × 10⁷, 1.0 × 10^8, and 1.0 × 10⁹ CFU/g of the B. amyloliquefaciens LSG2-8 for 56 days. After 56 days of feeding, twenty four fish were randomly selected to test various growth, immune and antioxidant parameters. Ten fish were challenged with Aeromonas hydrophila for 14 days; the mortality rate was recorded 14 days after infection. The results showed that B. amyloliquefaciens LSG2-8 could significantly increase the growth parameters of R. lagowskii's, such as final body weight, weight gain rate, specific growth rate, and feed efficiency (p < 0.05). Further examination revealed the activity of antioxidant enzymes, Nrf-2 mRNA, and Keap-1 mRNA gene expression in the intestine and liver, and the serum immune index of R. lagowskii in the 1.0 × 108 CFU/g were all significantly higher compared to the other groups. Furthermore, fish fed a diet supplemented with B. amyloliquefaciens LSG2-8 had a significantly lower (p < 0.05) post-challenge mortality rate than the control fish. In summary, the research results showed that B. amyloliquefaciens LSG2-8 could improve the growth performance, immune function, antioxidant capacity, and disease resistance of R. lagowskii and be used in aquaculture.

Modulation of humoral immunological and antioxidant responses and gut bacterial community and gene expression in rainbow trout, Oncorhynchus mykiss, by dietary lactic acid supplementation

The present study was conducted to find the effects of dietary lactic acid (LA) supplementation on growth performance, hematological characteristics, humoral antioxidant and immunological factors, intestinal gene expression and bacteriological parameters in rainbow trout, Oncorhynchus mykiss. The fish (104 ± 0.90 g) were randomly distributed in twelve tanks (150 L water) as four treatments, receiving diets supplemented with 0, 5, 10, and 20 g/kg LA for 70 days. At the end of the feeding trial, no significant differences were observed in the fish growth performance and survival among the treatments. Blood/plasma red blood cell (5-20 g/kg LA), white blood cell (10 g/kg LA), hematocrit (5 and 10 g/kg LA), hemoglobin (5 and 10 g/kg LA), superoxide dismutase (10 g/kg LA), glutathione peroxidase (10 g/kg LA), total antioxidant capacity (10 g/kg LA), lysozyme (5-20 g/kg LA), and alternative complement activity (10 g/kg LA) significantly increased, as malondialdehyde (10 g/kg LA) significantly decreased in the LA-treated fish. Dietary LA supplementation induced no significant changes in the intestinal defensin gene expression, but significantly up-regulated the expression of toll-like receptor-3 (5-20 g/kg LA), Mx-9 (5-20 g/kg LA), and heat shock protein-70 (5 g/kg LA) genes; the highest expressions were observed at 5 g/kg LA supplementation. Dietary LA supplementation significantly increased total bacterial count (5 and 10 g/kg LA), Lactobacillus sp. (5-20 g/kg LA), and Bacteroides sp. (5-20 g/kg LA), but decreased Streptococcus iniae (5-20 g/kg LA) in the fish intestine; the highest Lactobacillus sp. And Bacteroides sp. Were observed in 10 and 5 g/kg LA supplementation, respectively. Overall, dietary LA supplementation, although has no significant effects on the fish growth performance, is beneficial to improve humoral antioxidant parameters, humoral and intestinal immunological parameters and intestinal microflora. According to the results, dietary 5-10 g/kg LA is recommended for the formulation of rainbow trout feed.

Mucosal and systemic immune effects of Bacillus subtilis in rainbow trout (Oncorhynchus mykiss)

Bacillus spp. are well known for their probiotic properties. Hence, the long-term feeding of Bacillus spp. strains to different fish species has been proved to confer beneficial effects regarding growth or pathogen resistance, among others. However, whether these strains could function as mucosal adjuvants, up-regulating immune responses after a single administration, has not yet been investigated in fish. Thus, in the current work, we have performed a series of experiments in rainbow trout (Oncorhynchus mykiss) aimed at establishing the potential of two Bacillus subtilis spore-forming strains, designated as ABP1 and ABP2, as oral adjuvants/immunostimulants. As an initial step, we evaluated their transcriptional effects on the rainbow trout intestinal epithelial cell line RTgutGC, and in gut tissue explants incubated ex vivo with the two strains. Their capacity to adhere to RTgutGC cells was also evaluated by flow cytometry. Although both strains had the capacity to modulate the transcription of several genes related to innate and adaptive immune responses, it was the ABP1 strain that led to stronger transcriptional effects, also exerting a higher binding capacity to intestinal epithelial cells. Consequently, we selected this strain to establish its effects on splenic B cells upon in vitro exposure as well as to determine the transcriptional effects exerted in the spleen, kidney, and gut after a single oral administration of the bacteria. Our results showed that B. subtilis ABP1 had the capacity to modulate the proliferation, IgM secreting capacity and MHC II surface expression of splenic B cells. Finally, we confirmed that this strain also induced the transcription of genes involved in inflammation, antimicrobial genes, and genes involved in T cell responses upon a single oral administration. Our results provide valuable information regarding how B. subtilis modulates the immune response of rainbow trout, pointing to the usefulness of the ABP1 strain to design novel oral vaccination strategies for aquaculture.

Biological Functions of Exopolysaccharides from Lactic Acid Bacteria and Their Potential Benefits for Humans and Farmed Animals

Lactic acid bacteria (LAB) synthesize exopolysaccharides (EPS), which are structurally diverse biopolymers with a broad range of technological properties and bioactivities. There is scientific evidence that these polymers have health-promoting properties. Most commercialized probiotic microorganisms for consumption by humans and farmed animals are LAB and some of them are EPS-producers indicating that some of their beneficial properties could be due to these polymers. Probiotic LAB are currently used to improve human health and for the prevention and treatment of specific pathologic conditions. They are also used in food-producing animal husbandry, mainly due to their abilities to promote growth and inhibit pathogens via different mechanisms, among which the production of EPS could be involved. Thus, the aim of this review is to discuss the current knowledge of the characteristics, usage and biological role of EPS from LAB, as well as their postbiotic action in humans and animals, and to predict the future contribution that they could have on the diet of food animals to improve productivity, animal health status and impact on public health.

Evaluation of the effects of Astragalus polysaccharides as immunostimulants on the immune response of crucian carp and against SVCV in vitro and in vivo

This experiment was conducted to evaluate the immunomodulatory effect and antiviral activity of Astragalus polysaccharides (APS) in crucian carp and epithelioma papulosum cyprinid (EPC) cells. Two diets containing 0 and 2 g/kg, APS were fed crucian carp for 56 days. The results showed that supplementation with APS significantly upregulated the immune-related indices including the levels of IgM, the activities of LZM, AKP and ACP, and the contents of C3 and C4. At the same time, compared with the CK group, adding APS to the feed significantly upregulated the expression of IL-8, IL-10, IL-1β, IFN-α, IFN-γ, MyD88, TGF-β and TNF-α in the spleen, kidney, liver and intestine of crucian carp. In addition, when the crucian carp were injected with SVCV, the survival rates of fish in the APS group and the control group were 48.87% and 13.76%, respectively. These results indicated that dietary APS could improve the resistance of crucian carp against SVCV infection. APS also significantly decreased viral titer and inhibited apoptosis induced by SVCV in EPC cells. These results indicated that APS could stimulate the immune response of crucian carp and improve the abilities of crucian carp and EPC cells to resist SVCV infection.

Effects of Multispecies Probiotic on Intestinal Microbiota and Mucosal Barrier Function of Neonatal Calves Infected With E. coli K99

Altered gut microbiota are implicated in inflammatory neonatal calf diarrhea caused by E. coli K99. Beneficial probiotics are used to modulate gut microbiota. However, factors that mediate host-microbe interactions remain unclear. We evaluated the effects of a combination of multispecies probiotics (MSP) on growth, intestinal epithelial development, intestinal immune function and microbiota of neonatal calves infected with E. coli K99. Twelve newborn calves were randomly assigned as follows: C (control, without MSP); D (E. coli O78:K99 + gentamycin); and P (E. coli O78:K99 + supplemental MSP). All groups were studied for 21 d. MSP supplementation significantly (i) changed fungal Chao1 and Shannon indices of the intestine compared with group D; (ii) reduced the relative abundance of Bacteroides and Actinobacteria, while increasing Bifidobacteria, Ascomycetes, and Saccharomyces, compared with groups C and D; (iii) improved duodenal and jejunal mucosal SIgA and total Short Chain Fatty Acids (SCFA) concentrations compared with group D; (iv) increased relative ZO-1 and occludin mRNA expression in jejunal mucosa compared with group D; and (v) enhanced intestinal energy metabolism and defense mechanisms of calves by reducing HSP90 expression in E. coli K99, thereby alleviating the inflammatory response and promoting recovery of mucosal function. Our research may provide direct theoretical support for future applications of MSP in ruminant production.

In vitro Selection of Synbiotics and in vivo Investigation of Growth Indices, Reproduction Performance, Survival, and Ovarian Cyp19α Gene Expression in Zebrafish Danio rerio

In this study, we tested the compatibility of two extracts from the plant Jerusalem artichokes and button mushrooms with two different Lactobacillus probiotics (Lactobacillus acidophilus; La and Lactobacillus delbrueckii subsp. Bulgaricus; Lb) to develop a synbiotic formulation to improve the growth, survival, and reproductive performances of farmed fishes. Initially, we employed in vitro approach to monitor the growth of the probiotic lactobacilli in the presence of the different doses of the plant-based prebiotics, with the aim of selecting interesting combination(s) for further verification under in vivo conditions using zebrafish as a model. Results from the in vitro screening assay in the broth showed that both the probiotic species showed a preference for 50% mushroom extract as a source of prebiotic. A synbiotic formulation, developed with the selected combination of L. acidophilus, L. bulgaricus, and 50% mushroom extract, showed a positive influence on the growth and reproductive performances of the zebrafish. Our findings also imply that the improvement in the reproductive indices was associated with the upregulation of a cyp19a gene. Overall results suggest that a combination of L. acidophilus, L. bulgaricus, and mushroom extract can be considered as a potential synbiotic for the successful production of aquaculture species.

The influence of probiotics of different microbiological composition on histology of the gastrointestinal tract of juvenile Oncorhynchus mykiss

This article presents results of the influence of three probiotic feed additive of various microbiological composition: Bacillus subtilis (VKPM B-2335); B. subtilis (OZ-2 VKPM-11966) + Bacillus amyloliquefaciens (OZ-3 VKPM-11967); Lactobacillus acidophilus (VKPM B-3235) on the growth and histology of the organs of the gastrointestinal tract of juvenile Oncorhynchus mykiss by morphometric parameters. These probiotic bacteria are the most commonly used in aquaculture. The effect of the probiotic feed additive led to the increase in fish growth and influenced different sections of the gastrointestinal tract. The biggest change was found in the mid intestine and the reliable difference compared with the control diet was obtained at the following parameters: lamina propria width, intraepithelial lymphocytes number of prismatic epithelium and goblet cells area. The changes in the pyloric appendages were less obvious but reported as playing an important functional role in digestion. The liver preserved normal functional structure in all series of the experiment except for the group with L. acidophilus, where hepatocyte small-drop vacuolization was observed. That might be connected with the change of the digest activity resulting from a decrease in secretory activity of the intestinal exocrinocytes. The use of all probiotic feed additives led to a similar change in morphometric parameters in all groups, which suggests a decrease in the immune response.

Short- and long-term probiotic effects of Enterococcus hirae isolated from fermented vegetable wastes on the growth, immune responses, and disease resistance of hybrid catfish (Clarias gariepinus × Clarias macrocephalus)

This study evaluated the short- and long-term effects of dietary supplementation with Enterococcus hirae strain UPM02 on the growth performance, immunity, and disease resistance of hybrid catfish (Clarias gariepinus × Clarias macrocephalus) against Aeromonas hydrophila infection. In the long-term trial, fingerling fish were fed diets containing 0 (control), 2 × 10⁵, or 2 × 10⁷ CFU/g E. hirae UPM02 for 120 days. Administration of E. hirae UPM02 had significant effects on the specific growth rate (SGR), feed utilization efficiency, body indices (P < 0.05), and gut villus physiology of the catfish. E. hirae UPM02 application also significantly increased the complete blood cell counts, phagocytic activity, respiratory burst, lysozyme activity, and alternative complement pathway hemolytic (ACH₅₀) activity in tested catfish throughout the experimental periods (P < 0.05). Dietary E. hirae UPM02 at both concentrations significantly increased the expression levels of the alpha-2-macroglobulin (α2M), CC chemokines, CXC chemokines, lysozyme c (LYZC), myeloperoxidase (MYE), NF-kappa-B1 p105 subunit (NF-K), and bactericidal permeability-increasing protein (BPIP) genes in the head kidney, liver, and spleen (P < 0.05) at days 80, 100 and 120 after application. However, heat shock protein 70 (HSP70) gene expression was slightly downregulated in these organs. Interestingly, fish fed the diets containing 2 × 10⁵ and 2 × 10⁷ CFU/g E. hirae UPM02 exhibited a significantly lower (P < 0.05) postchallenge mortality rates (32% and 30%, respectively) after 14 days of A. hydrophila challenge than the control fish (58%). In short-term (28 days) application to juvenile catfish, the two concentrations of E. hirae did not affect all growth parameters. Nevertheless, these concentrations markedly elevated all tested immune parameters, similarly to long-term application. Immune-related gene expression was significantly upregulated at day 28 in the head kidney, at day 14 in the liver, and at day 7 in the spleen in fish treated with the two concentrations of the probiotics (P < 0.05). Mortality at 14 days after challenge with A. hydrophila in the groups receiving the two concentrations of the probiotic was significantly lower than that in the control group, at 28, 24, and 48%, respectively (P < 0.05). These results collectively suggest that dietary supplementation with E. hirae UPM02 at 2 × 10⁵ and 2 × 10⁷ CFU/g effectively influenced immune responses, enhanced disease protection, and stimulated immunity-related gene expression in hybrid catfish under both short- and long-term application. However, growth enhancement was significantly evidenced with long-term application only.

Evaluation of probiotic properties of Lysinibacillus macroides under in vitro conditions and culture of Cyprinus carpio on growth parameters

Cyprinus carpio is an important freshwater fish in aquaculture. It was used for the isolation of potential probiotic strain for aquaculture applications. The most dominant strain was isolated on MRS agar from the gastrointestinal (GI) of C. carpio and identified as Lysinibacillus macroides using molecular marker 16S rRNA gene. Various probiotic properties such as acid and bile tolerance and antibiotic susceptibility were analysed under in vitro conditions. Further, formulate pelletized feed using probiotic (L. macroides) in different concentrations (2, 4, 6 and 8%). Rearing of C. carpio was carried out 45 days and fed with formulated feed. The highest length (5.14 ± 0.07 cm) and weight (3.56 ± 0.07 g) of C. carpio fingerlings was recorded in the 8% LM probiotic pelletized feed, while in fingerlings fed with control showed lower in the length (3.02 ± 0.13 cm) and the weight (0.92 ± 0.04 g) on the 45th day of the experiment. Both percentage of weight gain (PWG) and specific growth rate (SGR) were significantly increased (P < 0.05) of C. carpio fingerlings fed with probiotic feed compared to control feed. Hence, the use of probiotic bacteria could be an encouraging alternative feed for future endeavours in the field of aquaculture. In conclusion, L. macroides can serve as probiotic for sustainable, competitive and promising beneficial bacteria to aquaculture industry.