Respiratory Burst Activity Research Articles

Dietary coriander (Coriandrum sativum L) oil improves antioxidant and anti-inflammatory activity, innate immune responses and resistance to Aeromonas hydrophila in Nile tilapia (Oreochromis niloticus)

The use of essential oils (EOs) as a natural alternative to antibiotics for disease prevention strategies is gaining much interest in recent decade. Coriander (Coriandrum sativum L.) essential oil is rich in bioactive compounds like linalool and geranyl acetate which have antioxidant, anti-inflammatory and antimicrobial activities. The present work was proposed to evaluate the inclusion levels of coriander oil in tilapia feed to enhance tilapia health and resistance to bacterial infection. Five iso-nitrogenous and iso-lipidic feeds were prepared with graded levels of coriander oil (0, 0.5, 1, 1.5 and 2%). The fish were then fed with the five experimental diet twice daily for a period of 60 days in triplicate. Haemoglobin, mean corpuscular volume, mean cell haemoglobin increased significantly in the coriander oil treated groups. The thrombocyte count was more in 2% inclusion level. The superoxide dismutase activity increased significantly in all the treated groups. The feeds with 1.5 and 2% coriander oil showed increased respiratory burst and myeloperoxidase activities while lysozyme and antiprotease activities were significantly higher in 1, 1.5 and 2% dietary treatments compared to control. The survival increased in dose dependent manner post challenge with an intraperitoneal injection of Aeromonas hydrophila at a LD50 dose of 5 × 106 cfu mL−1. The feed containing 1, 1.5 and 2% of coriander oil showed 89, 100 and 100% survival respectively compared to 39% in control diet. The expression level of IgM and IL-8 increased significantly post challenge with A. hydrophila in coriander oil fed groups. The expressions of TNFα, IL-1β, TGFβ and HSP 70 genes, however, decreased significantly in the treated groups compared to control. Histopathological examination of spleen showed large melano-macrophage centers in control and 0.5% coriander fed group with signs of necrosis and vacuolation post A. hydrophila infection, whereas 1, 1.5 and 2% treated groups showed normal architecture of spleen. From the above observations it can be concluded that coriander oil with 1% incorporation in feed improves tilapia health and resistance to bacterial infection.

Effect of Dietary Moringa oleifera Leaves Nanoparticles on Growth Performance, Physiological, Immunological Responses, and Liver Antioxidant Biomarkers in Nile tilapia (Oreochromis niloticus) against Zinc Oxide Nanoparticles Toxicity

The current study addresses the influence of Moringa oleifera leaves nanoparticles (MO-NPs) on growth, biochemical, immunological, and hepatic antioxidant alterations induced by zinc oxide nanoparticles toxicity in Nile tilapia (O. niloticus). Fish (N = 180) were divided into four groups with replicates. The first one was set as a control group and the second group was fed an MO-NPs-enriched diet (2.5 g/kg diet). The third group was exposed to 8 mg/L ZnO-NPs, while the forth group was exposed to 8 mg/L ZnO-NPs and fed on MO-NPs (2.5 g/kg diet) for 2 months. Exposure of O. niloticus to 8 mg/L ZnO-NPs induced the following consequences: a sharp decrease in the growth parameters; a marked increment in the biochemical biomarkers (glucose, cortisol, and liver enzymes (ALT, AST, ALP); a significant increase in serum renal products, urea and creatinine, cholesterol, and LDH levels. Nonetheless, the dietary MO-NPs supplementation for 2 months significantly alleviated the ZnO-NPs toxicity and significantly enhanced the growth indices, plus normalizing the physio-biochemical levels in the exposed group to ZnO-NPs toxicity to reach the levels of the control group. The MO-NPs markedly improved hepatic antioxidant biomarkers, MDA, and TAC, while, decreasing SOD, CAT, and GSH levels to be near the control values. Moreover, supplemented fish in MO-NPs (2.5 g/kg diet) and exposed to ZnO-NPs provided a remarkable increase in the immune profile (respiratory burst (RB) activity, lysozyme, and total immunoglobulins (IgM)) compared to the ZnO-NPs-intoxicated group. Based on the findings of the study, the exposed O. niloticus to ZnO-NPs were immune-antioxidant-depressed, besides showing growth retardation, and physio-biochemical alterations. On the other hand, a supplemented diet with MO-NPs is a novel approach to ameliorate ZnO-NPs toxicity for sustaining aquaculture and correspondingly protecting human health.

Potential assessment of probiotic Cystobasidium benthicum LR192 strain in mice.

Antibiotic bacterial resistant is a huge concern worldwide and probiotics offer an alternative to mitigate it. This study explores Cystobasidium benthicum LR192 as possible probiotic through microbiological and immunological analyses in mouse model. C. benthicum LR192 was isolated from lichens in a hyperarid environment in Baja California Sur, Mexico. First, microbiological analysis was assessed using 1 × 105CFU/mL in YM broth: resistance to 1% of bile salts and pH of 2, 3 and 5 (control). Then, yeast capacity to adhere onto the intestinal mucosa and safety to mouse splenocytes were tested. Finally, immunological parameters (phagocytic ability, respiratory burst and myeloperoxidase activities, nitric oxide and IgG production) and immune-associated gene expression (IL-1β, IL-6 and INF-γ) were determined in daily supplemented mice with the yeast (1 × 108CFU) at days 10 and 15. The results indicate that C. benthicum LR192 has medium resistance to bile salts and low pH, can adhere to the intestine and did not cause cytotoxicity in splenocytes. Immune parameters and immune-related gene expression indicated immunomodulation at day 10 and 15, specially in leucocytes challenged with Escherichia coli. In conclusion, C. benthicum LR192 showed safe potential probiotic properties, but further studies should be performed to confirm it as a probiotic prospect for humans.

Alleviative effects of astragaloside IV on cyclophosphamide-induced oxidative damage and immunosuppression in tilapia (Oreochromis niloticus)

Astragaloside IV (ASIV) has effects of antioxidation and immunologic enhancement. However, there are few reports on the application and potential mechanism of ASIV in aquaculture. In this study, we investigated the effect of ASIV on growth, antioxidation, and immune function of tilapia. Tilapia were fed a diet containing 0.1, 0.2, and 0.5 g·kg−1 ASIV for 60 days, followed by an intrapleural injection of 50 mg·kg−1 cyclophosphamide (CTX) to induce oxidative damage and immunosuppression. Then tilapia were weighed and blood, liver, spleen, kidney, and intestinal were collected. The results showed ASIV increased the final weight, relative weight rate, and specific growth rate of tilapia, reduce conversion ratio, and reduced the morphological lesions of tissues. Meanwhile, ASIV alleviated CTX-induced oxidative damage by improving antioxidant activity in serum and tissues and inhibiting lipid peroxidation. Additionally, ASIV attenuated the immunosuppression of tilapia caused by CTX, regulated immunochemical indexes in serum, increased the viability of peripheral blood leukocytes and head kidney macrophages, and restored respiratory burst activity (O2−) in head kidney macrophages and splenocytes. Furthermore, qPCR data showed ASIV up-regulated antioxidant-related gene expression of nrf2, ho-1, gpx3, and cat and immune-related gene expression including C3 and igm. In conclusion, ASIV as a feed additive can not only improve the growth performance but also enhance the antioxidant capacity and immune function of tilapia, which may be associated with the ability of ASIV to scavenge free radicals, reduce lipid peroxidation levels, and stabilize numbers of immune cells.

Dietary supplementation of Pseudoalteromonas piscicida 1UB and fructooligosaccharide enhance growth performance and protect the whiteleg shrimp (Litopenaeus vannamei) against WSSV and Vibrio harveyi coinfection

P. piscicida 1Ub and FOS were evaluated for their potential synbiotic effects on growth, immunological responses, and disease resistance against white spot syndrome virus and V. harveyi coinfection, the major pathogen in whiteleg shrimp aquaculture. Four different supplemented diets were used to feed the experimental shrimp for 40 days: control (control, no probiotic, and prebiotic), probiotic (PRO, P. piscisida 1UB 108 CFU mL−1), prebiotic (PRE, FOS 0.5% w/w), and the synbiotic (SYN, PRO + PRE). Shrimp's body weight, weight gain, specific growth rate, feed conversion ratio, survival, digestive enzyme activity, and metabolism-related gene expression were all evaluated on day 40. After 40 days, shrimp were infected with WSSV as the primary infection and V. harveyi as the secondary infection 24 h later. Shrimp were then grown for seven days and fed with a control diet. Survival, total hemocyte count (THC), differential hemocyte, phenol-oxidase (PO), respiratory burst activity (RB), and immune-gene expression were all analyzed at 0, 3, and 7 days after infection. The results showed that the PRO, PRE, and SYN supplementation improves whiteleg shrimp growth performance, immune responses, and protection against WSSV and V. harveyi coinfection. The increased activity of digestive enzymes and metabolism-related genes correlates with higher growth performance. The increase in THC, PO, RB, and immune-related gene expression after coinfection was associated with a significant reduction in shrimp mortality. Our findings also suggest that supplementing with synbiotics improves the overall performance of whiteleg shrimp significantly more than probiotics or prebiotics only.

Dietary Supplementation with Prebiotic Chitooligosaccharides Enhances the Growth Performance, Innate Immunity and Disease Resistance of Nile Tilapia (Oreochromis niloticus)

Prebiotics acting as immunosaccharides exhibit immunomodulatory functions to improve the immune defense of the host against infectious diseases. The purpose of the present study was to investigate the effects of dietary chitooligosaccharide (COS) supplementation on the growth, innate immunity and disease resistance of Nile tilapia (Oreochromis niloticus) fed a diet containing 0.4%, 0.8% and 1.2% COSs for 8 weeks. The results showed significant increases in weight gain (WG), feed efficiency (FE) and specific growth rate (SGR) in COS-supplemented fish compared to fish in the control group. The fish exhibited a significant decrease in cumulative mortality in fish fed 0.8% and 1.2% COS when challenged with Streptococcus iniae. The immune parameters, including phagocytotic activity (PA), respiratory burst (RB) activity, and superoxide dismutase (SOD) activities of the head kidney and serum lysozyme, as well as the expression of TNF-α, IL-1β and IL-8, were revealed in 0.8% and 1.2% COS-supplemented fish. These results demonstrated that COS could be used as a prebiotic and that dietary supplementation with 0.8% COS could improve growth performance and innate immunity against pathogen infections in Nile tilapia.

Interactive effects of dietary phosphorus and microbial phytase on growth performance, intestinal morphometry, and welfare of Nile tilapia (Oreochromis niloticus) fed on low-fishmeal diets

One of the industries with the fastest growth rates in the world is aquaculture. However, as fish meal (FM), the most expensive component of aquafeeds, is increasingly replaced with plant protein, the amount of phosphorus (P) in fish diets decreases as a result of plant proteins' high phytate content, which chelates P. Inorganic P is a dietary supplement that increases fish development and feed utilization, but its high inclusion in aquafeeds causes eutrophication due to environmental contamination. Consuming dietary phytase can make more P available, which lowers the amount of inorganic P in fish diets. The present study assessed the effects of replacing inorganic P in Nile tilapia (O. niloticus) diets with a hybrid microbial phytase (HMPhyt) derived from bacteria hybrid (Buttiauxella gaviniae, Yersinia mollaretti, and Hafnia sp.) on growth and welfare. Fish (1.50 ± 0.16 g) were divided into 18,100-L tanks with 20 fish each, and they were fed one of six low FM diets that were both isonitrogenous (300 g/kg) and isocalorific (17 kJ/g). The control diet had no P or HMPhyt supplements (0P + 0HMPhyt), the second diet contained 0.2 g/kg (1000FTU/kg) HMPhyt only (0P + HMPhyt), the third diet contained 100% P (13.0 g/kg) only (100P + 0HMPhyt), and the fourth to the six diets contained 75% (9.8 g/kg) P (75P + HMPhyt), 50% (6.5 g/kg) P (50P + HMPhyt), or 25% (3.3 g/kg) P (25P + HMPhyt). Fish were fed the experimental diets three times each day for 56 days, until they appeared satisfied. In comparison to the control diet (0P + HMPhyt), the results reveal that dietary phytase and/or inorganic P significantly increased Nile tilapia growth indices and feed intake (P < 0.05) than the control group. In contrast, there were no differences in the feed conversion ratio or the percentage of fish that survived among the various fish groups (P > 0.05). In addition, fish fed on P and/or HMPhyt containing diets had significantly greater counts of red and white blood cells, packed cell volume, and hemoglobin, as well as higher intestinal villi width/height, and absorption area compared to the control group. In contrast, higher levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and malondialdehyde were found in fish fed the control diet (0P + HMPhyt), while higher levels of superoxide dismutase, catalase, lysozyme, and respiratory burst activity were found in fish fed the inorganic P and/or HMPhyt based diets As a result, dietary HMPhyt (1000 FTU/kg) can totally substitute inorganic P in Nile tilapia diets without having any negative impacts on the fish's welfare or growth.

Peptide hydrolysate from fish skin collagen to prevent and treat Aeromonas hydrophila infection in Oreochromis niloticus.

Aquaculture with an intensive system can both increase production and the disease risk. The use of antibiotics to reduce pathogens has bacterial resistance consequence. Peptides have rapidly gained more attention due to their antibacterial and immunomodulatory properties important to combat pathogens. This study aimed to determine the effectiveness of peptide hydrolysate against Aeromonas hydrophila in vitro and in vivo in Nile tilapia. The peptides obtained from fish skin collagen of tilapia, milkfish, and catfish were applied in different doses. Protein content and hydrolysis degree of the peptide were also measured. The peptides were tested in vitro using A. hydrophila. For in vivo test, The peptides and positive control treatments used A. hydrophila bacteria, while negative control treatment used a phosphate buffer saline (PBS). The results showed that all three peptide hydrolysates had similar protein content. The highest hydrolysis degree was shown by milkfish collagen hydrolysate. In vitro assay revealed that 12.5% milkfish skin collagen obtained the highest antibacterial activity. In vivo assay showed that the phagocytic activity, respiratory burst, and lysozyme activity was higher in preventive control than therapy, positive control, or negative control treatments. The growth and survival rate in preventive control was also better than positive control or therapy treatment. This study concludes that the peptide hydrolysate can inhibit the growth of A. hydrophila. Peptide hydrolysate from milkfish skin collagen at 12.5% dose was more effective in preventing the A. hydrophila infection, regarding the immune response, growth, and survival.

Effects of dietary supplementation of Pseudomonas aeruginosa FARP72 on the immunomodulation and resistance to Edwardsiella tarda in Pangasius pangasius

Edwardsiella tarda is one of the serious bacterial pathogens infecting both cultured and wild catfish urging an immediate need for effective protection strategies. This study assessed the effects of dietary supplementation of Pseudomonas aeruginosa FARP72 at 108 cells/g feed (PA diet) for 30 days on the innate immunity parameters, viz., respiratory oxidative burst (ROB) activity, lysozyme, ceruloplasmin, myeloperoxidase, in-vitro nitric oxide (NO) production in addition to the expression of immune genes encoding interleukin-1β, C3 and transferrin in yellowtail catfish Pangasius pangasius and their resistance to Edwardsiella tarda challenge at a sub-lethal dose of 1.50 × 107 cells/fish. A significant increase in the innate immunity parameters was noted in PA diet-fed catfish on 30 dpf compared to the control. Post E. tarda challenge, the levels of immune parameters increased significantly and peaked at 5 dpi irrespective of feeding to confer protection against E. tarda. Their levels, however, decreased on and from 10 dpi. The results on the expression of immune genes encoding interleukin-1β, C3 and transferrin in the kidney and liver tissue samples of PA diet-fed P. pangasius upon challenge with E. tarda further confirmed the ability of P. aeruginosa to stimulate primary immune organs at the gene level. The effects of feeding P. aeruginosa FARP72 on the immune functions of catfish as examined by the functional immune assays, thus, demonstrating the innate immune responses of catfish that are differentially stimulated by the PA diet. The findings of our study would help evolve management strategies to confer protection against E. tarda infection in commercial catfish aquaculture.

Effects of white mustard (Sinapis alba) oil on growth performance, immune response, blood parameters, digestive and antioxidant enzyme activities in rainbow trout (Oncorhynchusmykiss)

A study was conducted to evaluate the effects of dietary supplementation of white mustard (Sinapis alba) oil (WMO) on growth performance, immune responses, digestive and antioxidant enzyme activities in juvenile rainbow trout (Oncorhynchus mykiss). For this purpose, fish (initial weight: 25.77 ± 0.13 g) were divided into four experimental groups in triplicate and fed ad libitum twice a day with diets containing WMO at 0 (control), 0.5, 1, and 1.5% of diet for 9 weeks. Three fish from each tank (n:9 per treatment) were sampled on 21st, 42nd, and 63rd days for further analyses. At the end of the feeding period, fish were challenged with Aeromonas hydrophila and Yersinia ruckeri in two separate experimental setups. Results showed that final weight, weight gain, and specific growth rate were significantly increased in all experimental groups compared to the control. Feed conversion ratio was similar among treatments. Respiratory burst and potential killing activity decreased in all experimental groups compared to the control (P < 0.05). Lysozyme and myeloperoxidase activities were elevated in all experimental groups at the end of the experiment compared to the control (P < 0.05). Cytokine gene expressions in the head kidney and intestine were elevated in all experimental groups compared to that of the control in general (P < 0.05). Hematological responses of the experimental fish groups were similar to that of the control (P > 0.05). Pepsin and trypsin levels decreased in all experimental groups (P < 0.05). In terms of antioxidant enzyme activities, significant improvement in liver superoxide dismutase, catalase, and glutathione s-transferase activities in all treatment groups were determined (P < 0.05). In addition, a significant decline in liver lipid peroxidation levels was recorded in all treated groups at all sampling times compared to the control (P < 0.05). At the end of this feeding trial, no significant differences (P > 0.05) were observed in survival against A. hydrophila among experimental groups compared to the control (P > 0.05). However, increased survival against Y. ruckeri was determined in experimental fish groups (P < 0.05). This study suggests that white mustard oil had a favorable effect on the overall health and growth of rainbow trout.

Characterization of Porcine Monocyte-Derived Macrophages Cultured in Serum-Reduced Medium.

Simple SummaryThe aim of this study was to provide an improved in vitro model of porcine monocyte-derived macrophages (MDMs) based on reduced-serum culture. The partial or complete absence of serum in media is suitable for experimental studies focused on molecules that are naturally present in serum or in cultures used for subsequent protein purification. Moreover, the benefit of serum-free or reduced-serum supplements follows the current trend of reducing FBS use in biological research. In order to confirm that a reduced-serum MDM culture is suitable for in vitro functional studies of porcine macrophages, we assessed their morphology, yield after differentiation, surface marker expression, respiratory burst, and phagocytic activity, as well as the induction of cytokine gene expression.The aim of this study was to establish a cell culture system for the generation of porcine monocyte-derived macrophages (MDMs) under reduced-serum conditions. Cultures based on either the Nu-Serum™ Growth Medium Supplement (NUS) or a conventional fetal bovine serum (FBS) were compared, which included the assessment of FBS from two different providers (FBS1 and FBS2). The data obtained confirmed the significant impact of culture conditions on in vitro-generated MDMs. The MDMs cultured under reduced-serum conditions showed increased levels of IL-1β and CD86 mRNA and a proinflammatory cytokine profile, characterized by the increased mRNA expression of IL-23p19, CXCL10, and CCL5. Phagocytic and respiratory burst activities were not adversely affected. Surprisingly, the difference between the two FBSs was much more pronounced than the effect of the reduced-serum supplement. The FBS1 culture conditions gave rise to macrophages with higher surface levels of CD14, CD16, and CD163, a lower CD80 mRNA expression, and an increased induction of IL-10 gene expression. In contrast, none of these trends were observed in macrophage cultures supplemented with FBS2. Instead, the FBS2 culture showed increased levels of IL-1b and CD86 mRNA. In conclusion, reduced-serum culture is a useful tool for in vitro porcine MDM generation, in line with the current research trend of reducing FBS use in biological research.

A review on Immunostimulatory and antioxidant potential of herbs, Curcuma longa L., Camellia sinensis L. Zingiber officinale and Allium sativum Linn. in fish health: a sustainable approach for a healthy aquaculture

The usage of antibiotics and chemotherapeutics agents in aquaculture and their undesired consequencesleads to the search for other alternatives. Plants are rich in active compounds includes alkaloids, flavonoids,terpenoids, phenols and polypeptides which proved to maintain a good health status in fish by acting asgrowth promoters, stress resistance and preventions of infections. Phytomedicine provides a cheaper sourcefor the treatment and greater accuracy than chemotherapeutic agents without causing toxicity. There arediverse medicinal plants in India which are being used extensively in aquaculture for several purposes.Present review focuses only on the immunostimulatory and antioxidant property of some common herbs;turmeric, green tea, ginger and garlic owing to their effectiveness and availability. The studied herbs possesspotent immunostimulant and antioxidant compounds which conferring early activation to the non-specificdefence mechanisms of fish and boosted the immune responses like phagocytic and respiratory burst activity,lysozyme activity, complement proteins, immunoglobulins (Igs), protease, anti-protease and alkalineprotease (ALP) and leucocytes promotion etc. It also inhibits the generation of oxygen anions and scavengesfree radical by increasing the antioxidant enzymes activity like catalase (CAT), glutathione (GSH), glutathioneperoxidase (GPx) and superoxide dismutase (SOD) during emergence of physiological disturbances. Theseherbs will promote the eco-friend health management of highly commercial fish species withoutcompromising the aquatic environment and ensure sustainable aquaculture with higher yield and nutrientcontent.

Growth performance, antioxidant activities, and immunological responses of hapa-reared thinlip mullet (Liza ramada) juveniles fed on diets supplemented with spirulina (Arthrospiraplatensis)

Spirulina (Arthrospira platensis) (SP) has been utilized for a long time as a valued feed supplement because of its proteinous content and other beneficial phytochemical compounds. Herein, we investigated the influences of SP-supplemented diets on growth, body somatic indices, digestive enzymes, hepatic antioxidant activities, and immunological responses of hapa-reared thinlip mullet (Liza ramada) juveniles. Fish were assigned in six triplicate groups and were fed for consecutive 60 days on the prepared experimental diets containing varying SP levels as 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 g/kg diet and defined as control (CNT or SP0), SP2, SP4, SP6, SP8, and SP10 groups, respectively. The results indicated that dietary SP supplementation linearly and quadratically improved the fish growth performance, and the highest growth indices were found in the SP8 group. However, dietary SP supplementation did not significantly alter feed conversion ratio (FCR), survival rate (%), hepato-somatic index, and viscera-somatic index among all experimental groups. Meanwhile, digestive enzymes (lipase, α-amylase, and proteases) in the mid-intestine were also linearly and quadratically increased in all SP-fed groups, and their uppermost values were noted in the SP8 group. Hepatic antioxidants such as superoxide dismutase, catalase, and total antioxidant capacity in SP-supplemented groups were significantly elevated than the CNT group. Conversely, hepatic malondialdehyde contents were decreased significantly along with increasing dietary SP-supplementation levels. The immunological parameters such as lysozyme, respiratory burst, and alternative complement activities were significantly elevated in SP-fed groups than in the CNT group. These findings evoked that feeding SP-supplemented diets (especially at 8.0 g/kg diet) significantly promoted the growth, digestive enzymes, hepatic antioxidant status, and immunity of L. ramada juveniles.

Pomegranate (Punica granatum) peel extract supplementation in diet influences growth performance, haemato-immunological responses and cytokine expression in pathogen- aggravated Labeo rohita fingerlings

Pomegranate peel extract (PPE) has been widely identified as a rich source of therapeutically active phyto-compounds, known for their beneficial effects in aquaculturable species. In this context, a 60-day feeding trial was carried out to evaluate the effect of supplementation of pomegranate peel extract (PPE) on growth performance, haemato-immunological responses and cytokine gene expression in Labeo rohita (rohu) fingerlings challenged with Aeromonas hydrophila. A total of 240 rohu fingerlings (3.25 ± 0.52 g) were randomly distributed into four treatment groups in triplicates with 15 fish per tank. The groups were fed with four different diets containing graded levels of PPE viz., 0 (control), 0.5, 1.0 and 1.5%. The results demonstrated significantly enhanced weight gain% and specific growth rate (SGR) in the group fed with 0.5% of dietary PPE. The cumulative survival post challenge to A. hydrophila was enhanced to 72.90% in 0.5% PPE fed group as compared to 20.01% in the control group. Haemato-immunological parameters in terms of respiratory burst activity (NBT), serum total protein, globulin and lysozyme activity displayed highest levels in L. rohita fed with the 0.5% PPE diet. Further, the dietary group supplemented with PPE at 0.5% level exhibited upregulated mRNA transcript levels of pro-inflammatory cytokines viz. IL-1β, TNF-α in different lymphoid organs such as gut, kidney and liver of L. rohita fingerlings post-challenge. In contrast, anti-inflammatory cytokine IL-10, was significantly down-regulated in infected rohu fed with 0.5% PPE. Taken together, the best optimum dosage or inclusion level at 0.5% PPE, obtained through the study, represented remarkable favourable variations in growth, haemato-immunological parameters and cytokine gene expression of L. rohita fingerlings. Thus, the dietary supplementation of PPE at 0.5% could effectively enhance different aspects of innate immunity alongwith disease resistance to A. hydrophila infection in L. rohita fingerlings.

Positive effects of dietary nanosized sodium butyrate on growth performance, immune, antioxidant indices, and resistance of Nile tilapia to waterborne copper toxicity

Although, copper (Cu) is commonly used in aquaculture as a chemotherapeutic agent to prevent and control algal blooms and bacterial infections, it could negatively impact the health and performance of aquatic animals. Moreover, sodium butyrate used as a feed additive plays a potential role in improving the performance and well-being of many aquatic species. Therefore, in this study, Nile tilapia, Oreochromis niloticus (L.) with average weight of 8.5–9.5 g, were fed on diets containing nanosized sodium butyrate (NSB) at levels of 0.0 (control), 0.25, 0.5, 1.0, 2.5, 5.0, and 10 mg/kg feed for eight weeks. Following the feeding period, fish from each treatment were subsequently exposed to waterborne Cu (0.5 mg/L) for further ten days. Results obtained herein revealed that with optimum values of 1.0–2.5 mg/kg diet, dietary NSB linearly and quadratically boosted fish performance, with no effects on the whole body composition of Nile tilapia. We also observed that when dietary NSB levels in Nile tilapia diets were increased from 1.0 to 10.0 mg/kg feed, serum alpha-amylase, lipase, and total proteases activities were linearly and quadratically increased compared with the control group. In NSB-fed fish, no changes in glucose, aspartate (AST), or alanine aminotransferase (ALT) levels, but significant increases in total proteins and total lipids levels were seen (notably at 2.5–10.0 mg/kg feed). Higher values of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), lysozyme (Lys), respiratory burst activity (RBA), and total immunoglobulin (total Ig) were also observed in NSB-fed fish particularly at 2.5–10.0 mg NSB/kg feed. Contrastively, the control fish exhibited highest glucose, AST, and ALT values coupled with lower total proteins and total lipids values after Cu exposure. The control fish exposed to Cu toxicity showed higher values of SOD, CAT, and GPx, as well as malondialdehyde and nitric oxide levels coupled with lowest values of Lys, RBA, and total Ig. Also, the Cu residue in the control fish’s body post-Cu exposure was significant higher than those of fish fed on NSB diets (5.0–10 mg/kg feed). Feeding Nile tilapia on NSB significantly reduced the Cu uptake and, subsequently, the Cu residue in the fish body. Hence, significant recovery of the above-mentioned variables was observed in NSB-fed groups, especially at 2.5–10.0 mg/kg feed treatments. Therefore, this study demonstrated that dietary NSB (1.0–2.5 mg/kg feed) has significant role in boosting fish performance, enhancing antioxidant-immune biomarkers, and reducing the Cu uptake and bioaccumulation in fish bodies.

Dietary brewer's spent yeast enhances growth, hematological parameters, and innate immune responses at reducing fishmeal concentration in the diet of climbing perch, Anabas testudineus fingerlings.

A 60-day feeding trial was conducted to optimally reduce the fishmeal level in climbing perch (Anabas testudineus) fingerling diet using a dietary brewer’s spent yeast biomass (BSY) based diet. In this study, five isonitrogenous (35% CP) and isocaloric (19.15 MJ/Kg) feeds were prepared by replacing 0 (BSY0), 25% (BSY25), 50% (BSY50), 75% (BSY75) and 100% (BSY100) of fishmeal protein using BSY protein. A total of 225 numbers of uniform-sized climbing perch fingerlings (3.29 ± 0.09 g) were randomly stocked in the 15 rectangular FRP (Fiber-reinforced plastic) tanks (150 L capacity). The experimental fish were fed twice daily at 4% BW for the first fortnight and later reduced to 3% BW based on satiation. At the end of the feeding trial, the weight gain (WG) of fish increased with the increasing BSY incorporation rates corresponding to fishmeal content and peaked at 77.88%, and beyond that, WG decreased. Food conversion ratios decreased as dietary BSY levels increased and peaked at 76.28%. All other growth and feed utilization parameters followed a similar trend of weight gain. Hepatosomatic index (HSI) and viscerosomatic index (VSI), A:G ratio, serum catalase activity, and monocytes were unaffected and the total serum protein, albumin, globulin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), respiratory burst activity, lysozyme levels, myeloperoxidase activity, hemoglobulin, red blood cells, white blood cells, neutrophils, eosinophils, lymphocytes, and gut protease activities were increased significantly (P < 0.05) with the increasing replacement levels and peaked between 25 and 75%. The serum SOD activity and total platelets were decreased, whereas the serum uric acid and gut amylase activities were increased significantly to the increasing levels of FM replacement in the diets (P < 0.05). Among treatments, the BSY100 resulted in an overall poor growth response combined with relatively reduced values in nearly all biochemical parameters. The whole-body composition was nearly unaffected. The integrated biomarker response of various biochemical indicators from the different treatments has shown that the 50% fishmeal protein can be optimally replaced by BSY, which would cause an 18% reduction in the Economic conversion ratio (ECR) and −270.28 gCO2e– reduction in carbon footprint value per kg of climbing perch fingerlings production.

Seasonal immune rhythm of leukocytes in the freshwater snakehead fish, Channa punctatus.

Annual rhythms are observed in many physiological processes and are an important approach to cope with seasonal stressors. The use of lower vertebrates as an experimental model is crucial to understand the evolution of this biological clock. This study aims to characterize the seasonal variability in the leukocyte immune responses in Channa punctatus. Leukocytes were harvested from peripheral blood and respiratory burst activity, leukocyte phagocytosis, and nitrite production were assessed to study innate immunity. Peripheral blood lymphocytes were segregated by centrifugation (density gradient) and proliferative responses of lymphocytes, in the presence of mitogens, were used to study cell-mediated immunity. Annual rhythms were validated in superoxide anion production, nitrite release and phagocytosis. Cosinor analysis revealed a differential pattern of lymphocyte proliferation which was dependent upon season and mitogen used. It was concluded that seasonal variation in immune activity might be associated with annual adaptation against diseases and the optimum immune status of seasonal breeders like fish helps them fight seasonal changes.

Effect of dietary β-mannanase supplementation on growth performance, digestibility, and gene expression levels of Cyprinus carpio (Linnaeus) fingerlings fed a plant protein-rich diet.

The aim of this study was to assess possible beneficial effects of dietary β-mannanase supplementation on the nutrient digestibility, growth performance, digestive and metabolic enzyme activity, and immune response of common carp (Cyprinus carpio) fed plant protein-rich diets. An experiment was conducted in triplicate, and a total of 225 fingerlings of common carp with an average body weight of 13.17 ± 0.12 g were stocked in 15 fiberglass tanks (15 fish/tank). Five dietary treatments (control 35% crude protein, plant-rich basal diet without supplement and four diets supplemented with β-mannanase from two sources (commercially available and locally isolated), each at two dosage levels (500 and 1,000 U/kg diet) were prepared and fed to respective groups of fish, twice a day (8:00 AM and 4:00 PM) at 4 % body weight. During the trial, changes in the level of DO and temperature ranged from 5.5 to 6.1 mg L−1 and 21.5 to 23.5°C, respectively. At the end of the feeding experiment, all fish in each tank were weighed and counted to determine growth parameters, while for the study of other indices, nine samples/treatment group were selected. The results of the study indicated a positive effect of both sources and dosage levels of β-mannanase supplementation on all studied indices, that is, significantly improved (P < 0.05), growth performance (%weight gain, specific growth rate), survival %, hematological indices (RBC, Hb, HCT, and MCHC), immunological indices (lysozyme activity, WBC, respiratory burst activity, and phagocytic activity), improved apparent digestibility of nutrients (crude protein, crude fat, and carbohydrates), and digestible energy. Furthermore, higher activity (P < 0.05) of the digestive enzymes (cellulase, lipase, and protease) and upregulation of MyoD gene in muscle and TNF-α gene in liver, intestine, and muscle were also observed, while the activity of serum AST (serum aspartate aminotransferase) and ALT (alanine transaminase) as compared to control group was significantly decreased (P < 0.05). Based on the results, β-mannanase supplementation (500 U/kg) could be recommended for obtaining better carp production when low-cost plant protein-rich diets are used.

Combination of Nigella sativa and Phyllanthus niruri as An Immunostimulant for The Prevention of White Spot Disease in Litopenaeus vannamei

Pacific whiteleg shrimp (Litopenaeus vannamei) is a very important commodity, which accounts for almost 70% of the total world shrimp production. However, this production is still threatened by disease attacks, one of which is caused by white spot disease (WSD). Herbs are widely used as immunostimulants as an effort to prevent diseases. Black cumin (Nigella sativa) and stone breaker (Phyllanthus niruri) have long been known as excellent immunostimulants in human. This study aimed to evaluate the potential of N. sativa and its combination with P. niruri as an immunostimulant in L. vannamei for preventing WSD. Tested shrimp (±3.0 g) were treated by N. sativa (N), P. niruri (P) and the combination of both (1N:1P, 2/3N:1/3P, 3/4N:1/4P, 1/3N:2/3, 3/5N:2/5P, 1/4N: 3/4P, 2/5N:3/5P) through feed for 28 days. They were then infected by white spot syndrome virus (WSSV) and observed for 7 days. The parameters observed included immune response and production performance. N. sativa was able to reduce the mortality of test shrimp infected with WSSV, with an RPS value of 71%. N. sativa can be combined with P. niruri in the right composition (1/2N:1/2P and 2/3N:1/3P), while the other combinations are antagonistic. The administration of the best treatments in this study, relatively did not affect the value of total hemocyte count, phenoloxidase activity, respiratory burst activity, hemolymph clotting time and production performance of tested shrimp.

Comparison of Different Dietary Fatty Acids Supplement on the Immune Response of Hybrid Grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) Challenged with Vibrio vulnificus.

Simple SummaryGroupers are one of Asia’s most valuable marine fish. The strong market demand has driven the expansion of grouper farming. However, with the intense farming practices, the farm rearing system was exposed, thus increasing the risk of infectious diseases. The present study was conducted to compare the use of different fatty acid immunostimulants on the survival, growth, and immune response of hybrid grouper infected with Vibrio vulnificus. Our results showed that the oleic acid formulated diet gives the highest fish survival rate and growth rate compared to the other fatty acid formulated diets and control diet after six weeks of feeding trial and one week of the bacterial challenge. Moreover, fish supplemented with an oleic acid diet showed significantly increased immune responses after being infected with V. vulnificus.Aquaculture has been expanding in Malaysia due to the increased demand for fish products. In addition, aquaculture faces challenges in maintaining feed suitability in support of the global growth of fish production. Therefore, improvements in diet formulation are necessary to achieve the optimal requirements and attain a desirable growth efficiency and health performance in fish. Seven weeks of study were conducted to compare the equal amounts of different fatty acids (2%) (oleic acid, stearic acid, palmitic acid, and behenic acid) on the survival, the growth, and the immune response of hybrid grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) against V. vulnificus. After six weeks of the feeding trial, fish were challenged with V. vulnificus for 30 min before continuing on the same feeding regime for the next seven days (post-bacterial challenge). Fish supplemented with dietary oleic acid showed significantly (p < 0.05) enhanced immune responses, i.e., lysozyme, respiratory burst, and phagocytic activities compared to the control diet group for both pre-and post-bacterial challenges. Following the Vibrio challenge, no significant effects of supplemented fatty acid diets on survival rate were observed, although dietary oleic acid demonstrated the highest 63.3% survival rate compared to only 43.3% of the control diet group. In addition, there were no significant effects (p > 0.05) on specific growth rate (SGR), white blood cell (WBC), and red blood cell (RBC) counts among all experimental diets. The results from this study suggest that among the tested dietary fatty acids, the oleic acid diet showed promising results in the form of elevated immune responses and increased disease resistance of the hybrid grouper fingerlings challenged with V. vulnificus.