Serum Lysozyme Activity Research Articles

Bactericidal efficiency of preparation based on essential oils used in aerosol disinfection in the presence of poultry

A disinfectant was created for aerosol disinfection of premises in the presence of poultry, which will help reduce microbial contamination of premises, increase survival, weight of poultry and economic efficiency of meat production in general. The preparation based on essential oils can be used for disinfection in the presence of poultry and at the same time exhibits a therapeutic and prophylactic effect on respiratory infections. This disinfectant has a colloidal solution of silver (Ag), benzalkonium chloride and essential oils of thyme, fir and eucalyptus. The preparation based on essential oils contains (per 100 g): benzalkonium chloride – 16.0 g; thyme oil – up to 2.0 g; eucalyptus oil – up to 2.0 g; fir oil – up to 2.0 g; colloidal solution of silver (Ag) – 20–30 mg; distilled water - up to 100 cm3. Aerosol sanitation of indoor air was carried out with 0.3% solution of preparation in the period before housing poultry and once a day from the 20th to the 35th day of growing broilers with aerosol cold mist generator Dyna-Fog Tornado (model 2897, construction type – ULV-electric spray gnerator, manufacturer – Curtis Dyna-Fog, Ltd., USA) at a dose of 50.0 cm3 per 1 m3 at an exposure of 60 minutes. The size of the aerosol particles is 20 μm. On days 1, 4, 8, 11, 15, 28, 37, and 42, the chickens were weighed, and the blood was taken for examination. Blood was examined to study the number of red blood cells, hemoglobin content, the bactericidal activity of blood serum, phagocyte activity of leukocytes, lysozyme activity of blood serum. According to the results of the research, the technological modes of air disinfection of poultry premises in the presence of broiler chickens were substantiated during the use of preparation, which contains nanoparticles (NP) of silver, benzalkonium chloride and essential oils. The optimal mode of aerosol treatment of poultry houses using a 0.3% solution preparation based on essential oils is 50 mL/m3 of a room with a 60-minute exposure. The use of air disinfection in the presence of chickens during broiler rearing and one treatment per day from 20 to 35 days of the chickens’ growth reduced the microbial pollution of indoor air. Thus, the concentration of microbial cells in the room where the chickens were kept was 230.2 ± 15.6 thousand microbial cell/m3. Sixty minutes after disinfection, the concentration decreased to 1.4 ± 0.4 thousand microbial cell/m3. In addition, the bodyweight of chickens at 6 weeks increased by 449.4 ± 16.3 g (15.9%) compared with the controls. The method and mode of air treatment did not adversely affect the development of the internal organs of the poultry and their physiological state, which is confirmed by studies of the morphological parameters of the chicken blood. The data obtained indicate a positive effect of the developed methods and modes of aerosol air treatment with the preparation based on essential oils on the growth and development of broilers.

Effects of Vitamin C and E Supplementation on Growth, Fatty Acid Composition, Innate Immunity, and Antioxidant Capacity of Rainbow Trout (Oncorhynchus mykiss) Fed Oxidized Fish Oil

This 10-week feeding experiment examined the effects of supplementing vitamin C (VC) and E (VE) in oxidized oil diets on growth, fatty acid composition, blood physiological indicators, innate immunity, antioxidant capacity, and liver and intestine histology of rainbow trout (Oncorhynchus mykiss). Four diets were produced including a fresh fish oil containing diet (FFO diet), an oxidized fish oil containing diet (OFO diet), and OFO diet supplemented with 500 mg kg–1 VC and 400 mg kg–1 VE (OFO+C500+E400 diet) or 1,000 mg kg–1 VC and 800 mg kg–1 VE (OFO+C1000+E800 diet). Four hundred and twenty fish averaging 46.9 ± 0.32 g were stocked into 12 tanks and fed the diets twice a day to visual satiety. The results showed no significant effect of OFO or vitamins supplementation on growth, feed intake and feed utilization (P > 0.05). The groups that received OFO and OFO+C1000+E800 diets had significantly (P < 0.05) lower hepatosomatic indices than the other groups. Muscle fatty acid composition showed decreased proportion of 15:0, 16:0, 16:1n-7, 16:2n-4, 18:1n-5, 18:2n-6 (linoleic acid) and total saturated fatty acids in OFO group. Whereas higher percentages of 20:3n-6 and 20:3n-3 were found in OFO group. In addition, the highest ratio of docosahexaenoic acid (DHA, 22:6n-3) to eicosapentaenoic acid (EPA, 20:5n-3) was detected in OFO+C500+E400 group. The highest serum triglyceride concentration was recorded in the OFO group. Serum aspartate aminotransferase activity increased in OFO and OFO+C1000+E800 groups compared to OFO+C500+E400 group. Furthermore, significantly higher alkaline phosphatase activity in blood was found in OFO and OFO+C500+E400 groups. Significantly lower serum lysozyme, antiprotease, superoxide dismutase, and catalase activities were recorded in OFO group compared to FFO and OFO+C500+E400 groups, and an opposite trend was observed for malondialdehyde concentration. Muscle VC and VE concentrations, and liver and intestine histology remained unaffected. To conclude, feeding diet containing oxidized oil with peroxide value of 182 meq kg–1 with/without VC and VE supplementation did not influence growth and tissue VC and VE concentrations of rainbow trout. However, supplementing 500 mg kg–1 VC and 400 mg kg–1 VE reversed the adverse effects of OFO on non-specific immune response and antioxidant capacity.

بررسی اثر ریزپوشانی با نانوذرات کیتوزان/آلژینات بر کارایی و ایمنی زایی واکسن تزریقی استرپتوکوکوزیس/لاکتوکوکوزیس در ماهی قزل الای رنگین کمان

In this study, the effect of injection of streptococcus / lactococcosis vaccine with alginate / chitosan microparticles on immunogenicity in rainbow trout was investigated. For this purpose, first S.iniae and L.garviae were cultured in TSB medium and inactivated with formalin, then the inactivated bacteria were finely coated with alginate / chitosan particles. 600 pieces of rainbow trout (14 ± 2.1 g) divided to four Treatments: Each treatment was divided into three replications as follows: the first treatment with encapsulated vaccine, the second treatment with uncoated vaccine and the third treatment with alginate / chitosan without bacteria, and the fourth treatment was injected with sterile PBS as control. The fish were fed and maintained for two months and on days 0, 20, 40 and 60, serum samples were prepared from the fish and immunity indicators included: serum antibody titer, complement activity, bactericidal, lysozyme activity, Leukocyte phagocytosis, serum protein and immunoglobulin levels, and expression levels of IL-6 and IgM in anterior kidney were evaluated. Treatments with both bacteria were challenged separately and mortality was compared between treatments. The results showed that the immunity indices in fish vaccinated with encapsulated vaccine improved compared to other treatments. Also, the expression of IL-6 and IgM genes and survival after bacterial challenge were significantly higher in encapsulated treatment than other treatments. Therefore, the vaccine microencapsulated method with chitosan and alginate microparticles is effective and can be used to improve the efficiency of streptococcus / lactococcosis vaccine in rainbow trout.

Potential effects of dietary seaweeds mixture on the growth performance, antioxidant status, immunity response, and resistance of striped catfish (Pangasianodon hypophthalmus) against Aeromonas hydrophila infection

Striped catfish (Pangasianodon hypophthalmus) is one of the important fish species in the world, which is widely cultured in several countries worldwide including Egypt. Aeromonas hydrophila infection showed a high prevalence in the farmed striped catfish negatively affecting its production causing economic loss. Therefore, the finding of functional feed supplements with antimicrobial activity is urgently needed. The use of marine seaweeds as feed supplements has produced satisfactory results as antibacterial agents. Accordingly, the present study was designed to evaluate the dietary effects of seaweeds mixture (Ulva lactuca, Jania rubens, and Pterocladia capillacea) extract (SME) on the growth performance, haemato-chemical parameters, antioxidant capacity, immune indices, and resistance of striped catfish fry against A. hydrophila infection. Four isonitrogenous (30% crude protein) diets were prepared to contain 0.0% (control), 1%, 2%, and 3% SME and were fed to striped catfish fry (1.7 ± 0.1 g) up to apparent satiety three times a day for 60 days. After the feeding trial, fish of each treatment were intraperitoneally injected with a virulent A. hydrophila strain and the relative percentage of survival (RPS) was recorded. The growth-stimulating activity of dietary SME was observed especially at 2% and 3% SME treatments. Similarly, haematological parameters (red blood cells, haemoglobin, haematocrit, and white blood cells) and serum protein profile (total protein, albumin, and globulin) were significantly (P < 0.05) improved, meanwhile serum alanine and aspartate aminotransferases were significantly (P < 0.05) decreased in fish fed with 2 and 3% SME diets. Serum creatinine and uric acid levels revealed no significant (P > 0.05) differences among the experimental groups. Hepatic malondialdehyde and serum nitrous acid levels were significantly decreased; meanwhile hepatic superoxide dismutase, catalase, and glutathione peroxidase levels were significantly increased in all SME-treated groups than the control one. Also, SME supplementations significantly increased the serum lysozyme, total immunoglobulin, and complement C3 activities with highest values at 2% and 3% SME treatments. Interestingly, after bacterial challenge, fish fed SME-supplemented diet were more resistant with the lowest fish mortality (15%) at the 3% SME diet, which exhibit the highest RPS (81.9%). Meanwhile the control group showed highest mortality (85%). According to the regression fitting curve, the current study recommends using the dietary SME with optimum levels of 2.25–2.5% to improve the growth performance, welfare status, and resistance of striped catfish fry against A. hydrophila infection.

Evaluation and compare of yeast β-glucan and carboxymethylglucan to improve the immunity and gut health of turbot fed diet containing 400 g kg−1 of soybean meal

In carnivorous fish feed, soybean meal was widely used as the alternative protein source to fish meal, but its negative influence on fish immunity and gut health limits its application. Yeast β-glucan is a well-documented immunostimulant and prebiotic, and carboxymethylglucan has higher potential bioactivity. The present work was to investigate and compare the effects of yeast β-glucan and carboxymethylglucan on the immunity and gut health of turbot Scophthalmus maximus (with initial weight of 7.6 g) fed a diet containing 400 g kg−1 soybean meal. Yeast β-glucan and carboxymethylglucan was respectively supplemented at the dose of 2 g kg−1. Enteritis was observed in fish fed the soybean meal diet. Beta-glucan or carboxymethylglucan supplementation significantly increased serum lysozyme activity, and the concentrations of IgM, complement 3 and complement 4. These two additives significantly decreased the infiltration of leukocytes in the lamina propria and submucosa and the expression of inflammatory cytokine of il-8. Compared with β-glucan, the fish fed carboxymethylglucan showed higher growth performance, feed utilization, lysozyme activity, concentrations of IgM, complement 3 and complement 4 but lower enteritis severity and inflammatory cytokines expression (il-1β, il-8, tnf-a and tgf-β). The structure of intestinal autochthonous bacteria was also altered by dietary yeast β-glucan and carboxymethylglucan. In conclusion, the present work confirmed the beneficial influence of dietary yeast β-glucan and carboxymethylglucan on turbots suffering from soy enteropathy. And carboxymethylglucan showed better protective effects than β-glucan against soybean meal-induced intestinal inflammation on turbot.

Growth hormone secretagogue peptide-6 enhances oreochromicins transcription and antimicrobial activity in tilapia (Oreochromis sp.)

Growth Hormone-Releasing Peptide 6 (GHRP-6) (His-(D-Trp)-Ala-Trp-(D-Phe)-Lys-NH2) is an agonist of the growth hormone secretagogue receptor. GHRP-6 mimics the effect of ghrelin. The present study focuses on the immunomodulatory effects of GHRP-6 in tilapia with and without the presence of Pseudomonas aeruginosa infection. GHRP-6 up-regulated the transcription levels of three piscidin-like antimicrobial peptides (Oreochromicins I, II, and III) and granzyme in a tissue-dependent manner. Antimicrobial activity stimulation in serum (lysozyme and anti-protease activity) was also confirmed. Besides, GHRP-6 enhanced the in vitro antimicrobial activity against P. aeruginosa in tilapia gills mucus and serum samples and decreased the bacterial load in vivo after infection with this Gram-negative bacterium. Our results evidenced, for the first time, a direct link between a growth hormone secretagogue ghrelin mimetic in fish and the enhancement of antimicrobial peptides transcription, which suggests that this secretagogue is capable to lead the activation of microbicidal activity in tilapia. Thus, these results open new possibilities for GHRP-6 application in aquaculture to stimulate the teleost immune system as an alternative treatment against opportunistic bacteria.

Influence of sow resistance indices on the growth of their offspring

Relevance. Pig breeding is primarily aimed at improving their reproductive and fattening qualities. To a lesser extent, the selection takes into account the indicators of the immune status of animals and their resistance to conditionally pathogenic microflora, apparently because due to the significant variability of individual blood parameters in ontogenesis, work with animals of many generations is required to improve these signs by breeding. The urgent task is to accelerate this process.Methods. 6 groups of animals were formed, including: 2 groups of 20 young sows of the Durock breed and large white breed and 2 groups of piglets, their offspring; 10 piglets from each group were weighed monthly, their linear measurements were determined. The study of natural resistance was carried out according to the following indicators: lysozyme, bactericidal and complementary activity of blood serum were measuredby conventional methods and in the author’s modification, hemagglutination reactionand bacterial agglutination — by conventional methods, indicators of phagocytosis were determined by conventional methods and in the author's modification.Results. A new method of comprehensive assessment of the level of natural resistance of pigs based on eight blood parameters — the resistance index (IR) — has been developed. For the first time, two coefficients — repeatability (rw) and persistence (h2) — were used as the statistical weight of traits. It was found that the live weight gain was higher in the offspring obtained from sows with an IR &gt; 60 points. The offspring of highly resistant sows also had an advantage in linear torso measurements.

Enhancement of immune response and resistance to Vibrio parahaemolyticus in Tilapia fish (Oreochromis mossambicus) by dietary supplementation of Portieria hornemannii

Supplementation of red algae can act as potent immune stimulator and have the effectiveness to induce immune related genes which play an important role in host defense mechanism. The objective of the present study is to scrutinize the potentiality of Portieria hornemannii (pH) extract to improve the disease resistance and immune response in Tilapia (Oreochromis mossambicus). Fishes were fed with PH diet for 45 days prior to the experimental challenge with Vibrio parahaemolyticus. Expression of immune related genes and immune parameters were analyzed at 1, 7 and 14 day of post challenge period. Fishes fed with PH diet showed higher percentage of survival when compared to the control group 14 day post challenge. Significant increase in antiprotease, serum lysozyme and NBT activity were seen in tilapia fed with PH extract diet (15 mg/g). These results simplified that PH extract can elevate the survival rate restraining the immune response in O.mossambicus.

ВЛИЯНИЕ ИММУНОМОДУЛЯТОРОВ НА НЕСПЕЦИФИЧЕСКУЮ РЕЗИСТЕНТНОСТЬ И ОБРАЗОВАНИЕ ОКСИДА АЗОТА (II) В ОРГАНИЗМЕ ТЕЛЯТ

The article presents data on the dynamics of bactericidal activity of blood serum against St. aureus and E. coli, and the lysozyme activity of calf blood serum against Micrococcus lisodeicticus, as well as nitrate and nitrite anions when immunomodulators are administered. It has been established that administration of «Fosprenil» increases bactericidal and lysozyme activity of blood serum, whereas, Imunophane increases nonspecific resistance without affecting lysozyme activity. Nitric oxide (II) has been shown to be directly involved in the mechanism of non-specific immunity. At the same time, the stimulation of serum lysozyme activity requires nitric oxide (II) formation in high concentrations (above 50 µmol/l).

ВЛИЯНИЕ «АРКУСИТА» НА БИОХИМИЧЕСКИЕ, ИММУНОЛОГИЧЕСКИЕ ПОКАЗАТЕЛИ СЫВОРОТКИ КРОВИ У СЕРЕБРИСТО-ЧЕРНОЙ ЛИСИЦЫ (SILVER-BLACK FOX)

The use of «Arkusit» at a dose of 20 μg / kg of body weight indicates a beneficial effect on the factors of nonspecific resistance of the silver-black fox. The concentration of alkaline phosphatase in the blood serum in the experimental group decreased by 1.8 times (P &lt;0.001), the ALT index - by 1.2 (P &lt;0.05). The concentration of glucose in the experimental group increased 2 times (P &lt;0.05) compared with the control group. In animals of the experimental group, the lysozyme activity of blood serum increased 1.3 times (P &lt;0.05), the OPR reaction and the phagocytic index - 1.4 times (P &lt;0.05), the bactericidal activity of blood serum - 1.8 times (P &lt;0.05). «Arcusit» stimulates the synthesis of gamma globulins, increases the opsonophagocytic, bactericidal activity of blood serum. Thus, the analysis of experimental data indicates that the drug «Arcusit» has a pronounced immunostimulating effect, providing the activation of factors of nonspecific resistance of the body of the silver-black fox.

Effects of dietary manganese supplementation on growth performance, antioxidant capacity, immune function and intestinal microbiota in Pacific white shrimp Litopenaeus vannamei

Water manganese (Mn) is apparently insufficient to meet aquatic animals’ metabolic requirement, and their food is considered as the major Mn source. Currently, researches reporting the effects of dietary Mn inclusion on physiological and metabolic function in Litopenaeus vannamei (L. vannamei) are very scarce. Therefore, 8-week feeding trail was conducted to determine dietary Mn requirement for L. vannamei and further evaluate the effects of dietary Mn supplementation on tissue Mn concentration, antioxidant enzyme activity, nonspecific immune enzymes activity and intestinal microbiota composition. Our results demonstrated that the optimum dietary Mn requirement for L. vannamei was determined to be 44.83 mg/kg based on the per cent weight gain; supplementing 39.57 mg/kg, 54.57 mg/kg and 72.67 mg/kg Mn significantly increased (p < .05) the activity of serum lysozyme (LZM), nitric oxide synthase and alkaline phosphatase, the activity of antioxidative capacity and glutathione in serum and hepatopancreas of L. vannamei. Supplementing 111.97 mg/kg Mn significantly increased (p < .05) hepatopancreas Mn concentration and serum LZM activity. Intestinal microbiota analysis showed that supplementing 39.57 mg/kg and 111.97 mg/kg Mn significantly influenced (p < .05) intestinal microbiota composition and function. These findings might help provide a scientific basis for the commercial application of Mn in L. vannamei.

Dietary supplementation of tributyrin improved the growth, feed utilization and intestinal histology of grass carp ( Ctenopharyngodon idella )

To investigate the effects of dietary tributyrin (TB) on grass carp (Ctenopharyngodon idella), five diets were prepared with supplementing TB at 0 (TB-0), 200 (TB-200), 400 (TB-400), 600 (TB-600) and 800 (TB-800) mg/kg and then fed to grass carp with initial body weight of 17.0 ± 0.2 g for 60 days. TB-400 and TB-600 groups presented higher weight gain, higher retention of protein, lipid, ash and lower feed conversion ratio than TB-0 group (p < .05), and TB-400 group also showed higher digestibility of dry matter and protein as well as intestinal amylase activity than TB-0 group (p < .05). Compared with the control, the serum superoxide dismutase activity was increased, and malondialdehyde content was decreased in TB-400 and TB-600 groups (p < .05), while TB-200 and TB-400 groups presented higher serum lysozyme activity than TB-0 group (p < .05). The villus height in foregut was increased in all the tributyrin-supplemented groups, but the villus height in midgut was increased only in TB-400 and T-600 groups (p < .05). The relative abundance of Erysipelatoclostridium tended to increase, and Aeromonas tended to decrease in TB-400 group. In conclusion, dietary tributyrin promoted the growth and feed utilization, enhanced serum antioxidant capacity and improved intestinal health of grass carp. Based on growth performance, the appropriate dietary supplementation of tributyrin is 443.5 mg/kg by using quadratic regression analysis.

Vitamin D3 protects turbot (Scophthalmus maximus L.) from bacterial infection

Accumulating evidence supports that vitamin D3 (VD3) possesses immunomodulatory properties besides its classical actions in calcium and bone homeostasis. In this study, juvenile turbots were fed with the diets containing 0 IU/kg VD3 or the optimum dose of 400 IU/kg VD3 for 8 weeks. To investigate the effects of VD3 on anti-infectious immunity in fish, 107 CFU Edwardsiella tarda was injected intraperitoneally to each juvenile turbot after the feeding trial. Our results showed that the mortality of infected turbots with dietary VD3 was much lower than that in VD3 deficient group, and the supplementation of dietary VD3 significantly reduced the bacterial load in the spleen of infected turbots. Further analysis demonstrated that the production of reactive oxygen species (ROS) in haemocytes and lysozyme activity in serum was elevated, and the responses of T cells and B cells were modulated in VD3-supplemented turbots. Moreover, the inflammation was significantly exacerbated in the infected turbots fed with 0 IU/kg VD3 compared to the fish fed with 400 IU/kg VD3. In addition, the head kidney macrophages (HKMs) in turbots were isolated and incubated with VD3in vitro, the results showed that VD3 significantly promoted the bactericidal activity in HKMs. In conclusion, our study has shown clear evidence that VD3 positively regulates the innate and adaptive immunity in fish, which is beneficial to the defense in fish against pathogen infection.

Effects of dietary sodium butyrate on growth performance, antioxidant capacity, intestinal histomorphology and immune response in juvenile Pengze crucian carp (Carassius auratus Pengze)

The current study was done to assess the effects of dietary sodium butyrate (SB) on growth performance, antioxidative capacities, intestinal microvilli morphology and intestinal immune response in juvenile Pengze crucian carp (Carassius auratus Pengze). Three treated diets and a control containing 0, 1,000, 2,000, 4,000 mg/kg SB (CON, SB1, SB2, SB3) were fed for juvenile Pengze crucian carp (5.49 ± 0.41 g) for 8 weeks. The results revealed that fish in SB2 and SB3 groups showed significantly higher growth performance compared to the control (P < 0.05). The body lipid was significantly decreased in SB-containing groups compared with that of the control (P < 0.05). Trypsin and lipase activities of fish fed SB2 and SB3 diets were both significantly higher than those of fish fed CON and SB1 diets (P < 0.05). However, no significant difference was found in α-amylase activity among all groups (P > 0.05). The intestinal total antioxidant capacity, catalase and superoxide dismutase activities were significantly enhanced in SB groups compared to the control (P < 0.05). The activities of brush border enzymes such as alkaline phosphatase, γ-glutamyl transpeptidase and Na+/K+-ATPase of fish fed SB2 and SB3 diets were both significantly higher than those of fish fed CON and SB1 diets (P < 0.05). However, the malondialdehyde contents of intestines in fish fed SB diets were remarkably reduced (P < 0.05). In addition, the serum total antioxidant capacity, superoxide dismutase, lysozyme activities and complement C3 content of fish fed SB2 and SB3 diets were significantly increased than those of fish in the CON (P < 0.05). The analysis of scanning electron microscopy and transmission electron microscopy demonstrated that density and length of microvilli were increased in the SB2 and SB3 groups (P < 0.05). The mRNA expression levels of pro-inflammatory gene IL-1β was significantly down-regulated in the SB2 and SB3 groups (P < 0.05). Moreover, the mRNA expression levels of anti-inflammatory gene TGFβ and IL-10 were significantly up-regulated in SB groups (P < 0.05). The mRNA expression levels of TNFα were not significantly different among all the groups (P > 0.05). Conclusively, our results showed the positive effects of the SB in Pengze crucian carp diets to improve the growth, intestinal microvilli morphology and intestinal immune response.

Effect of dietary Andrographis paniculata leaf extract on growth, immunity, and disease resistance against Aeromonas hydrophila in Pangasianodon hypopthalmus

ABSTRACT Aeromonas hydrophila severely hampers the farmed catfish production. A 60-day feeding trial was conducted to study the effect of Andrographis paniculata leaf extract on growth, immunomodulation, and disease outbreak against A. hydrophila in Pangasianodon hypophthalmus. A total of 180 juveniles of P. hypophthalmus (avg. wt. 123.33 ± 1.8 g) were distributed randomly in four groups following a completely randomized design in triplicate. Four experimental diets—C (no extract), T1 (1%), T2 (2%), and T3 (4%)—were prepared and fed twice daily. Growth metrics were calculated after 45 days and challenged with A. hydrophila. Relative percentage survival (RPS) was recorded over 15 days postchallenge. Results indicated that A. paniculata extract has a positive effect on hematobiochemical parameters and immune response. The highest (P < 0.05) pre- and postchallenge serum lysozyme activity, respiratory burst activity, and globulin level were found in the T2 group and lowest in the T0 group. Significantly (P < 0.05) higher percentage weight gain and SGR and lowest FCR were found in the T2 group than in the other groups. RPS was highest (P < 0.05) in the T2 group, followed by the T1 and T3 groups, compared to the control. Results suggest that A. paniculata leaf extract at a level of 2% could improve growth, immunity, and disease resistance against A. hydrophila by enhancing innate immunity in P. hypophthalmus.

Silver nanoparticles as an antibacterial agent in Oreochromis niloticus and Sparus auratus fish

A trial was carried out to assess the potential use of chemically synthesized silver nanoparticles (AgNPs) with two concentrations (5 and 10 µg/L) as an antibacterial agent in Oreochromis niloticus and Sparus auratus against Streptococcus agalactiae and Vibrio alginolyticus respectively. All AgNPs were with a mean of 26 nm in diameter. The particles were negatively charged (−30.7 ± 0.45 mV). In different ways, the in vitro AgNP antibacterial activity was investigated against S. agalactiae and V. alginolyticus in different ways showing clear inhibition zones of the two AgNP concentrations dose-dependent manner. In vitro measurement of extracellular proteins of pathogenic S. agalactiae and V. algenolyticus against AgNPs and the ultrastructural interaction between AgNPs and these bacterial pathogens using transmission electron microscopy (TEM) revealed AgNPs have good antibacterial properties. O. niloticus and S. auratus were exposed to AgNPs for 28 days. Some groups were challenged with S. agalactiae and V. alginolyticus respectively. Haematological, biochemical and immunological parameters and phagocytic activity, phagocytic index, respiratory burst activity of neutrophils and serum lysozyme activity were estimated in addition to the concentration of minerals. Histopathological examinations of all fish groups were explored. From the investigation above, we concluded that AgNPs have significant deleterious effects on O. niloticus exposed to 5 and 10 µg/L of AgNPs, appearing a significant decrease in leukocytes, red blood corpuscles (RBCs) count and haemoglobin concentration the fish on day 28 of the trial, with more deleterious effect with challenging fish by S. agalactiae and V. algenolyticus. In addition, AgNPs caused a substantial increase in liver enzymes with a reduction in total protein, albumin and globulin in the fish and considerably decreased the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Additionally, there was a significant decrease in sodium (Na) and potassium (K) content, nitroblue tetrazolium (NBT) and lysozyme activity (LYZ) in all groups of O. niloticus and S. auratus. In addition, lower survival rates disturb histopathological findings; meanwhile, S. auratus exposed to 5 and 10 µg/L of AgNPs showed antibacterial potency and immunostimulatory effects, which appeared in their higher survival rates and induced immune parameters and histopathological findings. In low concentration (5 µg/ml of AgNPs), AgNPs were less cytotoxic, especially in S. auratus, representing an alternative antimicrobial compound against V. algenolyticus. Further studies are still to be explored to clarify the protective role of the AgNPs and the recovery period needed for AgNPs to be entirely safe for usage as an antibacterial for each fish species.

Evaluation of ibuprofen contamination in local urban rivers and its effects on immune parameters of juvenile grass carp.

Ibuprofen as a non-steroidal anti-inflammatory drug can be detected in the aquatic environments all over the world. This study evaluated the effects of ibuprofen on the immune parameters of juvenile grass carp at the concentration in real environments which were determined by detecting its concentrations in the surface water of local rivers. The concentration of ibuprofen ranged from 13.2 to 95.5 ng/L with a mean value of 47.9 ng/L in the surface water of local rivers detected by solid-phase extraction followed by LC-MS/MS analysis. Accordingly, juvenile grass carp were exposed to 4.8, 48.0 and 480.0 ng/L of ibuprofen for 14 days. The serum lysozyme activity of these fish decreased, while the serum creatinine levels were not affected after the exposure. Moreover, the mRNA expression of interleukin 6 in the skin and interleukin 1 beta and tumor necrosis factor alpha in the gills was enhanced by this exposure. These results collectively suggest that ibuprofen at environmentally relevant concentration can affect the immune parameters of juvenile grass carp, providing an insight into the possibility of this contaminant to modify the immunostatus of fish.

Impacts of dietary konjac glucomannan supplementation on growth, antioxidant capacity, hepatic lipid metabolism and inflammatory response in golden pompano (Trachinotus ovatus) fed a high fat diet

This study examined the effect of konjac glucomannan (KGM) supplementation in diets with different lipid levels on growth, antioxidant capacity, hepatic lipid metabolism and inflammatory response in juvenile pompano (Trachinotus ovatus). Triplicate groups of fish (12.07 ± 0.21 g) were fed eight experimental diets containing two lipid levels of 9% (basal-fat diet, BFD) and 18% (high-fat diet, HFD), and four levels of KGM (0, 0.5, 1 and 2%) for 60 days. Pompano fed HFD exhibited markedly lower growth and feed efficiency than fish fed BFD, and KGM supplementation, particularly at 1% inclusion, significantly improved growth performance and feed efficiency in fish fed both BFD and HFD. In addition, Pompano fed HFD showed higher whole-body lipid and lower protein contents than fish fed BFD. Irrespective of dietary lipid level, whole body, dorsal and ventral muscle were reduced by dietary KGM supplementation up to 1% while the opposite was found for whole body protein content. Dietary KGM also significantly reduced the HSI, liver lipid contents, as well as lipid droplets in the liver. Supplementation of KGM to both BFD and HFD significantly reduced serum total cholesterol, triglyceride, low-density lipoprotein cholesterol and free fatty acids levels. Furthermore, irrespective of dietary lipid level, increasing dietary KGM supplementation enhanced serum IgM level, lysozyme and alkaline phosphatase activities, and reduced serum alanine aminotransferase and aspartate aminotransferase activities. Dietary KGM also increased liver total antioxidant capacity, superoxide dismutase and catalase activities, and decreased malondialdehyde concentration in fish fed both HFD and BFD. Dietary KGM significantly increased serum glutathione peroxidase, superoxide dismutase and catalase activities and reduced malondialdehyde concentrations in fish fed BFD, and enhanced serum total antioxidant capacity and glutathione peroxidase activity in fish fed HFD. Supplementation of KGM increased the expression of genes associated with lipid catabolism (pparα, cpt1, hsl) and lipid transport (fabp1, apoB100 and cd36), and decreased the expression of lipid anabolism related genes (srebp1, pparγ, fas and acc). Moreover, the expression of pro-inflammatory cytokines including tumor necrosis factor α and interleukin-8 were down-regulated, while expression of the anti-inflammatory cytokine transforming growth factor β1 was increased by KGM supplementation. In conclusion, supplementation of KGM at 1% of diet improved growth, feed efficiency, antioxidant capacity, hepatic lipid metabolism and inflammatory responses in juvenile pompano, and can mitigate excessive deposition of lipid in tissues of farmed fish.

Transformation of fish waste protein to Hermetia illucens protein improves the efficacy of poultry by-products in the culture of juvenile barramundi, Lates calcarifer

Promoting a circular economy via the transformation of food waste into alternative and high-value protein sources for aquaculture diets is a novel approach to developing alternative raw materials to fishmeal (FM). This approach can reduce the ecological impact on the aquatic environment and simultaneously can provide an option for sustainable food waste management. In this context, we report a 56-day trial of feeding barramundi, Lates calcarifer on four iso‑nitrogenous and iso-lipidic diets where the control (0PBM-0HI) was a FM-based diet and the other test diets replaced FM protein with mixtures of a poultry by-product meal (PBM) and a full-fat Hermetia illucens (HI) larvae meal reared on fish waste: the test diets were 85% PBM + 15% HI (85PBM-15HI), 80% PBM + 20% HI (80PBM-20HI) and 75% PBM + 25% HI (75PBM-25HI). Fish fed PBM-HI-based diets showed an equal growth rate and amino acid profile when compared to the control group. Among all serum metabolites, alanine aminotransferase and glutamate dehydrogenase decreased in fish fed PBM-HI-based diets, whilst total protein levels improved in the same diets. Serum lysozyme and bactericidal activity were unchanged which supported the observation of similar infection rates against V. harveyi. Except for the kidney and intestine, catalase activity in the serum and liver increased in fish-fed PBM-HI-based diets. In assessing the gastrointestinal mucosal morphology, the goblet cells producing neutral mucins were higher in PBM-HI-fed fish than the control. PBM-HI diets also enhanced bacterial richness and diversity and increased abundance for Lactobacillus, Clostridium, and Ruminococcus. In summary, combining full-fat HI with PBM allowed complete replacement of FM with no negative effects on growth whilst improving gut health. Such diets would be beneficial for the aquaculture industry, both ecologically and economically, as well as providing value-adding to animal waste as alternative protein sources for aquafeed production.

A Solid-State Fermentation (SSF) supplement improved performance, digestive function and gut ultrastructure of rainbow trout (Oncorhynchus mykiss) fed plant protein diets containing yellow lupin meal

A nutritional investigation was conducted to determine whether growth performance, feed efficiency and midgut morphology of rainbow trout (Oncorhynchus mykiss) is affected by United Kingdom cultivars of Yellow Lupin (Control, Y) (LC) compared to the addition of a commercial solid-state fermentation product (SSF) in separate dietary treatments 0.1 and 0.5% (LS0.1 and LS0.5, respectively). At the end of feeding trial, LC- and LS0.1-fed fish did not differ from one another, whilst significant improvement was observed in LS0.5 fed fish (P < 0.05). Apparent digestibility of crude protein and crude fibre were significantly higher in fish fed LS0.1 and LS0.5 than LC. No significant differences (P < 0.05) in Haemoglobin (Hb) concentrations were observed among dietary treatments. Fish fed the 0.1% SSF inclusion exhibited significantly (P < 0.001) higher haematocrit (Hct) concentration than all other treatments. Significantly (P < 0.005) higher serum glucose levels were observed in FMC fed fish compared to fish fed LC and LS0.1, whilst elevation was also observed in LS0.5 over LC and LS0.1. Activity of serum lysozyme was significantly (P < 0.05) higher in the LS0.5 treatment compared to LC, S0.1 and FMC groups. Fish fed 0.5% SSF were observed to have a significant (P < 0.05) reduction in goblet cell counts (GC) compared to those fed LC and LS0.1.). Median enterocyte height (EH) of LS0.1 and LS0.5 fed fish did not differ from one another but were both significantly greater than LC fed fish. Mean microvilli length (MVL), diameter (MVD) and enterocyte apical area (EAA) did not differ significantly between dietary treatments (P > 0.05). Fish fed 0.5% SSF displayed a higher microvillar percentage coverage (MVCV) compared to fish fed LC and LS0.1. Total alkaline protease (TAP), trypsin and chymotrypsin activities in the digesta of fish were unaffected by dietary treatment (P > 0.05). Activity of alkaline phosphatase (ALP) in digesta was significantly (P < 0.05) higher in SSF treatments than LC. Activity of L-leucine aminopeptidase (LAP) in digesta was marginally significantly (P = 0.045) higher in LS0.1 SSF fed fish than LC fed fish. Activity of LAP was also significantly higher in LS0.5 fed fish than LC fed fish.