Respiratory Burst Activity Research Articles

Dietary Administration Effects of Microbial Exopolysaccharide from Bacillus subtilis P1 on Growth Performance and Immunity in Nile Tilapia (Oreochromis niloticus)

Exopolysaccharide (EPS)-producing bacteria were isolated from the intestines of freshwater fish as prebiotics. Among the isolates, Bacillus sp. P1 was the potent EPS producer, with a high EPS production, and was then identified as Bacillus subtilis P1 based on 16S rRNA and biochemical characteristics. The produced microbial EPS was characterized by its functional groups by FTIR, showing a 90.20% correlation to inulin, while the EPS molecular weight was approximately 105 Da with a high PDI (>1.5). Moreover, the EPS from B. subtilis P1 was assessed for prebiotic properties by growing probiotic bacteria, and significant cell growth occurred in sugar-free TSB with 0.5% EPS (p < 0.05). EPS exhibited approximately 55.37% DPPH radical scavenging at 20 mg/mL and inhibited certain fish pathogens at 400 μg/mL (10–13 mm inhibition zone). Low EPS cytotoxicity was confirmed (<1% hemolysis) prior to use as immunobiotics in Nile Tilapia (Oreochromis niloticus) diet supplementation. Nile tilapia growth and immune response were monitored after feeding with control (C), basal diet (BD), and treatment (T): BD + EPS 5 g/kg. In the T-group, the weight gain (WG), % specific growth rate (SGR), and average daily gain (ADG) significantly increased compared to the control (p < 0.05) by week 4, with no negative effects on blood chemistry parameters. Lysozyme activity and respiratory burst activity in T-groups were significantly higher than the control (p < 0.05), with a 50% RLP survival rate of Nile Tilapia infected by Aeromonas veronii in the T-group after a two-week challenge. On the other hand, the proximate analysis revealed higher protein content in the T-group. These findings suggest that EPS from B. subtilis P1 in fish diets efficiently supports fish growth and stimulates innate immune response in Nile Tilapia, thus showing potential as the immunobiotics for aquaculture.

Hematobiochemical Changes, Immunological Response and Immune Gene Expression in Nile Tilapia (Oreochrom niloticus) Experimentally Infected with Shewanella putrefaciens

Background: In this work, hematobiochemical changes, immunological responses, and histopathological changes in Nile tilapia (Oreochromis niloticus) experimentally infected with Shewanella putrefaciens were studied. Methods: O. niloticus was experimentally infected with S. putrefaciens (4SK/SRLFDA/19) at a concentration of 1.508×106CFU/ml per fish. Gross symptoms, namely hemorrhage on the body surface, skin discoloration, slow or nervous behavior, shallow necrotizing ulcers on the skin, fin erosions and abdominal distension were observed 5 to 6 days after infection. Fish were anesthetized and blood samples were collected at 0, 2, 4, 7, 10, 14, 20 and 27 days after the experimental infection to assess the hematobiochemical and immunological responses. For haematobiochemical responses, tests that included hemoglobin (Hb), leukocyte count (Lc), erythrocyte, hematocrite (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), cholesterol (CHO), glucose (GLU) and triglyceride were assessed. Result: Values of hematocrit, hemoglobin, albumin, globulin, erythrocyte, MCHC, cholesterol and triglyceride were significantly (p less than 0.05) decreased. Lc, MCV, MCH, and glucose values were significantly (p less than 0.05) increased. Respiratory burst activity (RBA) and serum total protein values were significantly (p less than 0.05) decreased. Relative expression of immune gene toll like receptor 4 (TLR4), stress genes heat shock proteins 70, 90 (HSP70, HSP90), oxidative stress gene glutathione S-transferases (GST) and inflammatory gene interleukin 6 (IL6) was significantly higher in experimentally infected fishes compared to control.

Growth performance, immunological, and biochemical responses of stinging catfish, (Heteropneustes fossilis) fingerlings reared in a biofloc-based production system

ABSTRACT A study was conducted to compare the high-density rearing of stinging catfish (Heteropneustes fossilis) fingerlings in both a control system and a biofloc system over 100 days. In the biofloc system, probiotics and a carbon source were added, while the control group had no additions. The biofloc system showed significantly (p < .05) higher floc volume (8.34 ± 1.33 ml L−1) and improvements in growth performance, survival rate, and biomass yield. Fingerlings reared in the biofloc system had increased digestive, oxidative enzyme activities and a lower feed conversion ratio. No changes were observed in the whole-body proximate composition between the groups. However, nonspecific immune responses, such as lysozyme and myeloperoxidase, were relatively improved, and other immune parameters like respiratory burst activity and total serum immunoglobulin were significantly increased in the biofloc system. In conclusion, biofloc-based rearing significantly enhanced the growth performance, feed utilization, and immunological conditions of stinging catfish.

Immune protective, stress indicators, antioxidant, histopathological status, and heat shock protein gene expression impacts of dietary Bacillus spp. against heat shock in Nile tilapia, Oreochromis niloticus

This research evaluated the efficacy of mixed Bacillus strains probiotic supplements in mitigating acute thermal-induced stress in Nile tilapia (Oreochromis niloticus). Three experimental fish groups involved 135 Nile tilapia (49 ± 2 g); one control (no added probiotics), 0.5, and 1% of selected Bacillus strains (B. subtilis, B. licheniformis, and B. pumilus) for 58 days. After the feeding period, growth parameters, immunological parameters, stress biochemical markers, and antioxidant parameters in addition to genes related to stress and histopathological changes in fish, were assessed; subsequently subjected to heat shock at 36 ± 0.5 ◦C for 2 h. Before the heat challenge, our results exhibited a marked increase in the growth efficacy (P < 0.05), lower marked serum levels of triglycerides and cholesterol, and tissue malondialdehyde (MDA) levels along with significantly increased superoxide dismutase (SOD) and catalase (CAT) enzymes activity in fish-fed Bacillus probiotic at 0.5% concerning the control group (P < 0.05). There were no significant changes in the serum levels of glucose, cortisol, lactate, phagocytic activity, respiratory burst (ROS), total immunoglobulin Ig, alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), total protein, albumin, globulin, uric acid, urea, creatinine, as well as HSP70, GST, and GPx mRNA expression in most of the probiotic groups compared to the control group (P > 0.05). When Nile tilapia was exposed to heat stress, supplementation with Bacillus probiotic in the diet significantly decreased most of the indices related to serum biochemical (ALT (P < 0.01; P < 0.001), AST (P < 0.01), LDH (P < 0.01), urea (P < 0.05), and creatinine (P < 0.01)), triglycerides (P < 0.001; (P < 0.01)), cholesterol (P < 0.01; (P < 0.05)), glucose (P < 0.001), and cortisol (P < 0.01; (P < 0.05)), with tissue oxidative stress MDA levels (P < 0.05), and HSP70 mRNA expression (P < 0.01; P < 0.001), aligned with the stressed control group. In addition, a notable upsurge in the total protein, albumin, globulin, phagocytic and ROS activities, and total Ig, as well as the enzymatic antioxidant ability (SOD, CAT) (P < 0.01), with GST and GPx mRNA expression (P < 0.05; P < 0.01), were shown in fish-fed Bacillus spp. post-exposure compared with the stressed control group. Besides, no histopathological alterations were revealed in the spleen and brain of fish pre- and post-heat exposure. According to our findings, diet supplementation of Bacillus species has the potential to combat the suppressive effects of heat shock in Nile tilapia.

Arginine alleviates LPS-induced leukocytes inflammation and apoptosis via adjusted NODs signaling

Arginine plays a key role in regulating the immune function of fish. To evaluate the effect of arginine on the immune response of largemouth bass (Micropterus salmoides), the effects of arginine on cell viability, NADPH oxidase activity, respiratory burst activity, and NO production of leukocytes were analyzed both in vitro and in vivo. In this study, we found that arginine could promote the respiratory burst activity of leucocytes both in vivo and in vitro. By incubating leukocytes with the combination of LPS and arginine, we found that arginine supplementation inhibited the expression of inflammatory genes (tumor necrosis factor-alpha, tnfα; interleukin(il) 8 and il10) and apoptotic genes (caspase3, caspase8, and caspase9) induced by LPS, as well as promoted the arginine metabolism. Arginine supplementation significantly induced (cd4-like)cd4 gene expression after LPS challenge. Further studies showed that LPS could significantly increase nucleotide-binding oligomerization domain containing 1 (nod1) gene expression, but decreased the nod2 gene. The arginine supplementation increased nuclear factor kappa-B (NF-κB) protein level. In conclusion, arginine can alleviate LPS-induced inflammatory response and apoptosis as well as induce cd4 gene expression against LPS challenge via adjusting the expression of NODs signaling.

Comparison of the Effects of Hesperidin Over 30- and 60-Day Intervals on Rainbow Trout: A Potential Biostimulant to Promote Growth, Immunological and Antioxidant Responses, and Disease Resistance

Abstract The current research evaluated the effects of dietary hesperidin (HSP) on growth parameters, digestive enzyme activities, innate immune markers, and antioxidant responses in rainbow trout, Oncorhynchus mykiss after the 30- and 60-day feeding trial. Then, specimens were subjected to Yersinia ruckeri infection for 14 days. For this, six hundred rainbow trout juveniles (initial weight; 25.49±0.40 g) were fed with different levels of HSP including 0 (HSP0; control), 50 (HSP50), 100 (HSP100), 150 (HSP150), and 200 (HSP200) mg/kg feed. After 60 days, dietary HSP100 supplementation significantly improved growth and feed efficiency indices. The optimal dose of HSP based on the regression test for WG and FCR detected 122 and 131 mg/kg, respectively. At the end of the 30th day, dietary HSP150 supplementation markedly boosted serum lysozyme (LYZ), myeloperoxidase (MPO), complement component C3, and immunoglobulin (Ig) levels, but decreased malondialdehyde (MDA) content. In the same period, dietary administration of HSP at the different concentrations markedly increased complement component C4 (HSP150 and HSP200), superoxide dismutase (SOD), skin mucus alkaline phosphatase (ALP) (HSP100–HSP200), skin mucus LYZ and catalase (CAT) (HSP100 and HSP 150), and skin mucus Ig level (HSP50–HSP200). After 60 days, all dietary HSP supplementation significantly improved lipase, serum C3, glutathione peroxidase (GPX), and skin mucus ALP, LYZ, and Ig levels, but decreased MDA, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) values. After 60 days, dietary administration of HSP150 induced a significant discrepancy in the activity of serum LYZ, MPO, respiratory burst (RB), and lactate dehydrogenase (LDH) compared to the control group. In the same period, dietary HSP supplementation at different levels induced a remarkable increase in digestive protease activity (HSP100), serum ACH50 and CAT activities (HSP100 and HSP150), skin mucus peroxidase and serum SOD levels (HSP100–HSP200), and serum C4 value (HSP50, HSP150, and HSP200), but markedly decreased ALP activity (HSP150 and HSP200). In addition, dietary HSP supplementation, especially HSP150, markedly boosted disease resistance against Y. ruckeri infection. The current data demonstrated that the oral administration of 100–150 mg/kg HSP has a high potential to promote growth performance, disease resistance, and faster induction of immune and antioxidant responses.

Immunological, Antioxidant, Growth Responses, and Disease Resistance of Rainbow Trout, Oncorhynchus mykiss, with Feeding Diets Supplemented with Lactobacillus salivarius and Lutein

Abstract The aim of the present study was to assess the effects of dietary supplementation with Lactobacillus salivarius (LS) ATCC 11741 and lutein (LU) on immunological, antioxidant, and growth responses, and resistance against Yersinia ruckeri infection in rainbow trout (Oncorhynchus mykiss). There were seven experimental diets containing un-supplemented diet (CTL), L. salivarius at 1 × 106 (LS6) and 1 × 108 (LS8) CFU/g, lutein at 50 (LU50) and 150 (LU150) mg/kg, L. salivarius at 1 × 106 CFU/g plus lutein at 50 g/kg (LS6+LU50), and L. salivarius at 1 × 108 CFU/g plus lutein at 150 g/kg (LS8+LU150). These diets were provided to the fish (N= 735; 14.0±0.38 g). After 60 days of feeding, all experimental treatments exhibited significantly higher growth performance, compared to the CTL treatment. The intestinal protease activity and the intestinal lactic acid bacteria population in the probiotic-treated fish were significantly higher than in the CTL fish. The intestinal lipase activity was only higher in the LS6+LU50 treatment, compared to the CTL treatment. Compared to the CTL treatment, the intestinal total bacterial count, and serum superoxide dismutase significantly increased in the LS6+LU50 and LS8+LU150 treatments. The serum catalase significantly increased in LU150, LS6+LU50, and LS8+LU150 treatments, and serum glutathione peroxidase significantly increased in the lutein-treated fish. All experimental treatments, particularly LS6+LU50 and LS8+LU150, had significantly lower serum malondialdehyde levels, compared to the CTL treatment. The levels of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase in LU50, LS6+LU50, and LS8+LU150 treatments were significantly lower than the CTL. All experimental treatments showed significantly higher serum lysozyme (LYZ), complement, blood respiratory burst activity (RB), and skin mucus alkaline phosphatase (ALP), compared to the CTL treatment. The highest serum LYZ, C4, total immunoglobulin (Ig), blood RB activity, and skin mucus peroxidase, ALP, and Ig were observed in the LS6+LU50 and LS8+LU150 treatments. All the experimental treatments, especially LS6+LU50, exhibited significantly lower mortality after the bacterial challenge compared to the CTL. In conclusion, dietary supplementation with 1 × 106 CFU/g L. salivarius and 50 mg/kg lutein can maximally improve growth performance, digestive enzymes, antioxidant parameters, immune responses, intestinal lactic acid bacteria, and resistance against yersiniosis in rainbow trout.

Dietary Chitosan Nanoparticles Enhance Growth, Antioxidant Defenses, Immunity, and Aeromonas veronii biovar sobria Resistance in Nile tilapia Oreochromis niloticus

While chitosan is widely used in aquaculture feed, chitosan nanoparticles (CNPs) offer potential advantages due to their enhanced absorption. This study investigated the safe use of CNP levels in Nile tilapia feed, evaluating its impact on growth, immunity, and disease resistance. Five experimental diets were formulated and supplemented with zero chitosan (served as a control group), 1g/kg of chitosan (CS), and 1, 3, and 5 g/kg of CNPs. Each diet was randomly assigned to three replicate groups of 45 fish per group (15 fish/tank) with an average weight of (42.10 ± 0.05g, mean ± S.E.) twice daily (09:00 a.m. and 4:00 p.m.) to apparent satiation for two months. At the end of the feeding trial, fish fed 5 g/ kg of CNPs had the highest growth performance. However, no significant variations (p &gt; 0.05) in somatic index were seen between the experimental groups. All chitosan and CNP-enriched groups exhibited improved intestinal morphology compared to the control group, characterized by increased villus length and width, reduced necrosis of intestinal tips, and better overall tissue integrity, with the CNP 3g and 5g groups demonstrating the most favorable intestinal structure. The CNP-treated groups (3, 5 g/kg) had significantly higher blood indices and serum globulin. Malondialdehyde (MDA) levels were lower in the CNP-treated groups compared to the chitosan macromolecule group. There was a substantial rise in glutathione (GSH), total antioxidant capacity (TAC), phagocytic index, and respiratory burst activity in the 5 g/kg CNP-treated group. The dietary addition of 5 g/kg of CNPs raised mRNA expression for TLR-2, MUC-2, and IGF-1, but there was no significant difference in HSP70 expression across treatments. After the experimental challenge with Aeromonas veronii biovar sobria, the groups that received 3 and 5 g/kg of CNPs exhibited the lowest mortality rates. Overall, the results suggest that including 5g/kg of CNPs in fish food is safe and effective for enhancing their health and growth, making it a promising addition to aquaculture feed.

Influence of pegylated graphene oxide nanoparticles on the respiratory burst and phagocytic activity of human neutrophils

Scientific and technological progress contributes to the discovery and production of innovative materials. The emergence of graphene is a clear example of this. Graphene is considered a promising material for use in nanobiomedicine and nanobiotechnology. It is therefore important to understand how it affects human immune cells. In a study, the effects of 5 and 25 μg/mL graphene oxide nanoparticles with lateral sizes of 100-200 nm and 1-5 μm, modified with linear and branched polyethylene glycol, on human neutrophils were investigated. The formation of reactive oxygen species was evaluated with a lucigenin as a chemiluminescence activator.Inaddition, we investigated theeffect of a 60-minute incubation of neutrophils with pegylated graphene oxide nanoparticles on the viability of these cells by staining with trypan blue and a 30-minute incubation on the uptake of fluorescein isocyanate-labelled E. coli. The percentage of neutrophils which engulfed E. coli and the uptake index were determined. Samples without added nanoparticles served as controls.A decrease in lucigenin-enhanced chemiluminescence of neutrophils was observed under the influence of two types of graphene oxide nanoparticles: 1-5 μm in size coated with linear polyethylene glycol, and 100-200 nm in size coated with branched polyethylene glycol, at a concentration of 25 μg/mL in the zymosan-stimulated version of the assay. No dependence of the effect on the particle size and the type of polyethylene glycol was observed. The indicators for spontaneous chemiluminescence of neutrophils did not change with the addition of PEGylated graphene oxide nanoparticles.A thirty-minute incubation of human neutrophils at 37 °C with PEGylated graphene oxide nanoparticles with lateral dimensions of 100-200 nm and 1-5 μm had no effect on the viability of these cells and on the percentage of neutrophils that engulfed E. coli. However, 1-5 μm graphene oxide modified with linear polyethylene glycol at a concentration of 25 μg/mL increased the amount of E. coli engulfed by neutrophils per cell.Thus, in the absence of cytotoxicity, PEGylated graphene oxide particles have multidirectional immunomodulatory effects on neutrophils. In this case, their concentration is decisive and not the size of the graphene oxide particles and the type of polyethylene glycol.

Quantitatively characterize the response of the hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) under elevated temperature stress

Global warming may affect the health of marine species. However, the collected information on quantitative assessment of response in fish under elevated temperature is poorly defined. The present study aimed to quantitatively evaluate the effects of the hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) under elevated temperature (33 °C and 36 °C, ET1 and ET2) stress for 14 days. As endpoints, we examined changes in body growth, hemato-immunological parameters, liver oxidative stress markers, as well as changes of the stomach digestive enzymes. Compared to the control, the body weight was significantly decreased in ET2 group for 14 d exposure, and a remarkable change of differential leukocyte counts of the fish was observed in ET1 group at 3 d and in ET2 group at 14 d. The respiratory burst activity of the hybrid grouper leukocytes markedly decreased in the treatment groups after 14-d exposure. Overall, the antioxidant enzyme activities and transcriptional levels of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GSH-PX) were markedly inhibited in the liver for 3-d and 14-d exposure. The expression levels of nf-κb mRNA were significantly inhibited while the expression levels of atp2b1 mRNA were significantly induced after 14-d exposure. The activities of pepsin and lipase in the stomach were significantly reduced. In addition, an innovative hazard classification system (ET-HCS) was developed to quantitatively characterize the stress response of the fish following elevated temperature treatments. The stress level of ET2 group for 14-d exposure was ranked as level IV (high stress), and the other treatments were ranked as level II (low stress). Taken together, the findings of this study further extend our understanding of quantitative assessment of response in fish under high-temperature stress, which provides valuable information for improving countermeasures of mariculture industry.

Identification and functional analysis of lysophosphatidic acid phosphatase type 6 (ACP6) gene in golden pompano (Trachinotusovatus)

Golden pompano (Trachinotus ovatus), a marine farmed fish, is economically valuable in China. Lysophosphatidic acid phosphatase type 6 (ACP6) is a type of histidine acid phosphatase and plays an important role in regulating host inflammatory responses and anti-cancer effects in mammals. However, its function in teleost remains unknown. The present study aimed to investigate ACP6 function in golden pompano. ACP6 from golden pompano was identified, cloned, and named TroACP6. The open reading frame of TroACP6 was 1275 bp in length, encoding 424 amino acids. The TroACP6 protein shared high sequence identity (43.32%–90.57 %) with the ACP6 of other species. It contained a histidine phosphatase domain with the active site motif “RHGART” and the catalytic dipeptide HD (histidine and aspartate). Meanwhile, TroACP6 mRNA was widely distributed in the various tissues of healthy golden pompano, with the maximum expression in the head kidney. The function of TroACP6 was analyzed both in vitro and in vivo, and the results revealed that the purified recombinant TroACP6 protein exhibited optimum phosphatase activity at pH 6.0 and 50 °C in vitro. Meanwhile, upon Edwardsiella tarda challenge, TroACP6 expression in tissues increased significantly in vivo. In addition, TroACP6 overexpression enhanced the respiratory burst activity and superoxide dismutase activity of head kidney macrophages in vivo. Furthermore, the overexpression and knockdown of TroACP6 in vivo had a significant effect on bacterial infection. In summary, the study findings indicate that TroACP6 in golden pompano is involved in host defense against bacterial infection.

Effects of dietary Jatropha gossypiifolia leaves extract on growth performance, antioxidant capacity, immune response, and disease resistance of African sharptooth catfish (Clarias gariepinus) infected with Aeromonas hydrophila

ABSTRACT This study investigated the effects of Jatropha gossypiifolia leaf extract (JGE) on the performance and immune response of African sharptooth catfish. Fish (6.43 ± 0.26 g, n = 450, 30/replicate) were fed diets supplemented with 0, 0.5, 1.0, 1.5, or 2.0 g JGE/kg in triplicate for 84 days. Thereafter, the fish were injected with Aeromonas hydrophila and observed for 14 days. Fish fed 1.0–1.5 g JGE had higher (P < 0.05) weight gain, protein efficiency ratio, and villi absorption area, with highest performance at 1.0 g JGE. All the fish fed JGE-supplemented diets had enhanced (P < 0.05) activities of glutathione-s-transferase and glutathione peroxidase, compared to fish fed control diet, while the variations in erythrocyte and leucocyte counts were insignificant (P > 0.05). The post-challenge fish fed JGE-supplemented diets had higher lysozyme, phagocytic, and respiratory burst activities and survival than the control treatment.

Impaired phagocytosis and oxidative respiratory burst activity in sickle cell anemia leukocytes

ObjectivesThis case-control study investigated the mode of leukocyte function in sickle cell anemia (SCA) to delineate the underlying immunopathology for early diagnosis and mitigate the increased bacterial infection risk in this patient population. MethodIn total, 90 participants comprising 24 hemoglobin (Hb)-AA, 22 Hb-AS, 23 steady state Hb-SS and 21 vaso-occlusive crisis state Hb-SS subjects were recruited for this study. The subjects were further divided into the following six groups: Hb-AA and Hb-AS subjects as control groups, Hb-SS subjects at steady state, Hb-SS subjects in a vaso-occlusive crisis state, Hb-SS subjects undergoing medication (Meds), and Hb-SS subjects undergoing medication plus blood transfusion (Meds/BT) group, respectively. Hematological analysis, Hb electrophoresis, leukocyte ratios, and leukocyte functional assays were assessed with standard methods, and interleukin 8 (IL-8) and L-selectin levels were evaluated using enzyme-linked immunosorbent assays. ResultsTotal leukocyte and monocyte counts were increased in the Hb-SS groups compared to the control groups. However, the Hb-SS groups had lower lymphocyte counts than the other groups (p < 0.005). Leukocyte viability was increased in the SCA groups, while phagocytic activities and oxidative respiratory burst were both reduced in the SCA groups (p < 0.005). Increased IL-8 levels were observed in all SCA groups (p < 0.05), whereas L-selectin levels of the Hb-SS steady and Hb-SS on Meds groups were decreased compared to the other groups (p < 0.05). The neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and platelet-to-lymphocyte ratio were higher in the SCA groups than the control groups (p < 0.05). ConclusionImpaired leukocyte phagocytic and oxidative respiratory burst activities constitute altered leukocyte function in SCA, which can increase their susceptibility to infections and the risk of mortality, especially during the crisis state. Novel therapeutic approaches can be tailored specifically to enhance these leukocyte functions and mitigate the increased infection risk in SCA.

Impact of Nutritional Tea Polyphenols on Growth, Feed Efficiency, Biochemical Traits, Antioxidant Capacity, Haematological Parameters and Immunity in Coho Salmon (Oncorhynchus kisutch).

To evaluate the impact of nutritional tea polyphenols (TPs) on body composition, growth, biochemical markers, antioxidant capacity, and hemato-immunological levels, a ten-week feeding experiment was carried out on coho salmon (Oncorhynchus kisutch, 180.51 ± 0.15 g). The control group was fed a basal diet; the T1, T2, T3, and T4 groups were fed 0.005%, 0.01%, 0.02%, and 0.04% TPs, respectively. These results demonstrate that adding TPs significantly (p < 0.05) increased the coho salmon fish's weight gain (WG), relative growth rate (RGR), condition factor (CF), feed efficacy (FE), daily growth rate (DGR), and specific growth rate (SGR). There was no discernible difference in the body compositions of the treated TPs and the control group (p > 0.05). In addition, the T3 group showed a significant (p < 0.05) decrease in GPT, LDL, HDL, TC, and CAT. Fish given a 0.02% diet containing TPs had significantly lower levels of malondialdehyde (MDA) in their liver; yet, the TP-treated groups had higher levels of SOD and CAT than the control (p < 0.05). The data analysis shows a significant rise in lysozyme, respiratory burst activity, bactericidal activity, and blood hematological parameters in the 0.01-0.04% TP groups. According to these findings, TPs could be a useful dietary supplement for raising the antioxidant status, growth parameters, haemato-immunological response, and whole-body composition of coho salmon fish.

Ecotoxicological Research on the Toxic Impact of Zinc Oxide and Silver Nanoparticles on Oreochromis mossambicus.

Silver nanoparticles (AgNPs) and Zinc oxide nanoparticles (ZnONPs) have been widely used and are eventually been discharged into the natural aquatic ecosystem. The current study examined and correlated the toxicity of AgNPs and ZnONPs on the Mozambique tilapia, Oreochromis mossambicus. Lethal concentration (LC50) was determined with four different concentrations (0.05, 0.10, 0.15, and 0.20 mg/L) of AgNPs and ZnONPs; subsequently, the fishes were exposed to sublethal concentrations for a period of 21 days, and the oxidative stress and antioxidant and nonantioxidant parameters were studied. Results revealed oxidative stress evinced by increased lipid peroxidation (LPO) protein carbonyl activity (PCA), glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) activity, metallothionein (MT) activity, and reduced glutathione in chronic exposure compared with acute exposure. Nonspecific immunological characteristics such as lysozyme (LYZ), myeloperoxidase (MPO), and respiratory burst activity (RBA) were also noticed in the serum. Furthermore, severe histological damages including damages in telangiectasia and epithelial cell hyperplasia were found in the combined treated group with Ag and ZnONPs than in individual treatments. When Ag and ZnONPs were combined, a reduction in the accumulation of Ag was observed in the liver, which increased drastically in individual exposure. The current findings highlight the importance of taking into account the combined exposure and correlation of NPs, their bioavailability, and toxicity in the aquatic ecosystem.

Immunotoxicity and oxidative damage in Litopenaeus vannamei induced by polyethylene microplastics and copper co-exposure

This study examines the combined effects of polyethylene microplastics (PE-MP) and copper (Cu2+) on the immune and oxidative response of Litopenaeus vannamei. PE-MP adsorbed with Cu2+ at 2.3, 6.8, and 16.8 ng (g shrimp)−1) were injected into L. vannamei. Over 14 days, survival rates were monitored, and immune and oxidative stress parameters were assessed. The results showed that combined exposure to PE-MP and Cu2+ significantly reduced the survival rate and decreased total haemocyte count. Immune-related parameters (phagocytic rate, phenoloxidase and superoxide dismutase (SOD)) and antioxidant-related parameters (SOD, catalase and glutathione peroxidase mRNA and enzyme) also decreased, while respiratory burst activity significantly increased, indicating immune and antioxidant system disruption. Additionally, there was a significant increase in oxidative stress, as measured by malondialdehyde levels. Histopathological analysis revealed severe muscle, hepatopancreas, and gill damage. These results suggest that simultaneous exposure to PE-MP and Cu2+ poses greater health risks to white shrimp.

Stimulatory Effects of Phyllanthus amarus Extract on the Growth Performance, Hematobiochemical Activity, Antioxidative Status and Immune Response of Clarias gariepinus

This study investigated the antibacterial activity of Phyllanthus amarus extracts and its influence on the performance of Clarias gariepinus fingerlings. The fish were fed diets containing 0.0, 0.5, 1.0, 1.5 or 2.0 g P. amarus methanol extract (PAE) / kg basal diet for 84 days. Thereafter, blood samples were collected for hematological and biochemical analyses. At the end of the 84-day feeding trial, fish were challenged with Aeromonas hydrophila, after which immune response parameters were measured. The data obtained were analyzed using one-way analysis of variance at p&lt;0.05. The results showed significant antibacterial activity of PAE against A. hydrophila, and its application at 0.5-1.5 g significantly promoted growth performance, with the highest at 1.0 g. Hematocrit, hemoglobin and lymphocytes were enhanced at 0.5-1.5 g PAE. All the fishes fed PAE-supplemented diets had lower concentrations of serum liver enzymes; while the values of creatinine, glucose and total bilirubin did not differ among the treatments. Glutathione peroxidase, glutathione‐S‐transferase, lysozyme, phagocytic and respiratory burst activities increased in all PAE-fortified treatments, with highest fish survival in 1.0 g PAE treatment. Therefore, the inclusion of 1.0 g Phyllanthus amarus extract is recommended as a dietary supplement for Clarias gariepinus.

LECT2 mediates antibacterial immune response induced by Nocardia seriolae infection in the northern snakehead

Leukocyte-derived chemotaxin-2 (LECT2) is a multifunctional immunoregulator that plays several pivotal roles in the host's defense against pathogens. This study aimed to elucidate the specific functions and mechanisms of LECT2 (CaLECT2) in the northern snakehead (Channa argus) during infections with pathogens such as Nocardia seriolae (N. seriolae). We identified CaLECT2 in the northern snakehead, demonstrating its participation in the immune response to N. seriolae infection. CaLECT2 contains an open reading frame (ORF) of 459 bp, encoding a peptide of 152 amino acids featuring a conserved peptidase M23 domain. The CaLECT2 protein shares 62%–84 % identities with proteins from various other fish species. Transcriptional expression analysis revealed that CaLECT2 was constitutively expressed in all examined tissues, with the highest expression observed in the liver. Following intraperitoneal infection with N. seriolae, CaLECT2 transcription increased in the spleen, trunk kidney, and liver. In vivo challenge experiments showed that injecting recombinant CaLECT2 (rCaLECT2) could protect the snakehead against N. seriolae infection by reducing bacterial load, enhancing serum antibacterial activity and antioxidant capacity, and minimizing tissue damage. Moreover, in vitro analysis indicated that rCaLECT2 significantly enhanced the migration, respiratory burst, and microbicidal activity of the head kidney-derived phagocytes. These findings provide new insights into the role of LECT2 in the antibacterial immunity of fish.

Fermented mahua oil cake in the diet of Labeo rohita: effects on growth performance, digestive enzyme activity and immune response

Market instability, increased competition, escalating price and reduced availability of conventional ingredients warrants the researchers to rely on alternative feed ingredients. This approach may help in producing aqua feeds in a sustainable and cost-effective way to accomplish the global food and nutritional securities. Mahua oil cake (Bassia latifolia) is an underutilized non-conventional ingredient that holds promise for incorporation into aqua feed following nutrient enhancement by solid-state fermentation. A five-month pond feeding trial was carried out to investigate the effects of Sachharomyces cerevisiae and Bacillus subtilis fermented mahua oil cake (MOC) on the production performance, nutrient utilization, digestive capacity, and innate immunological responses of Labeo rohita fingerlings. For this, two iso-nitrogenous feed were formulated and prepared incorporating fermented MOC at different levels i.e. 0 and 40 percentage replacing soybean meal and other feed ingredients and fed to rohu fingerlings of two treatment groups in pond culture for 5 months duration. Improved growth performance, feed conversion ratio, feed intake, protein efficiency ratio and digestive capacity were observed in fish fed diets with 40 percent of fermented MOC compared to control. Innate immune responses parameters (respiratory burst activity, myeloperoxidase, lysozyme and hemaglutination activities) were significantly higher (P &amp;lt; 0.05) in fishes fed with fermented MOC. Therefore, we conclude incorporation of solid state fermented mahua oil cake up to 40% level in diet of L. rohita fingerlings in pond culture without any adverse effects on growth, nutrient utilization and innate immune response.

Effect of dietary mannan oligosaccharide inclusion on production parameters of Farfantepenaeus aztecus cultured in a biofloc system

AbstractThe effects of dietary mannan oligosaccharide (MOS) supplementation in a biofloc system on growth performance, whole‐body proximate composition, whole‐body fatty acids, nonspecific immune parameters, antioxidant enzyme activities, digestive enzyme activity, and gut microbiota of brown shrimp, Farfantepenaeus aztecus, were investigated. Shrimp were fed five diets containing different levels of MOS doses (MOS0: basal diet, MOS1: 0.1%, MOS2: 0.2%, MOS3: 0.3%, and MOS4: 0.4%) during the 90‐day trial. The results indicated that all MOS‐supplemented shrimp showed significantly higher growth rates and better feed utilization than shrimp fed the control diet. Experimental diets had varying effects on the nonspecific immune parameters and antioxidant enzyme activities, indicating that MOS supplementation resulted in significant differences in the parameters except for respiratory burst activity. Significantly higher protease activity was observed in shrimp fed MOS1 and MOS2 diets compared with MOS0, MOS3, and MOS4 diets. Shrimps fed MOS2 and MOS3 diets had the highest lipase and amylase activities among all groups. Proteobacteria were the most abundant phylum in all groups and were higher at increasing MOS doses. In conclusion, these results suggest that supplementing the diet of brown shrimp in the biofloc system with 3 g kg−1 of MOS may improve production parameters.