Effect of Licorice (Glycyrrhiza glabra) Extract as an Immunostimulant on Serum and Skin Mucus Immune Parameters, Transcriptomic Responses of Immune-Related Gene, and Disease Resistance Against Yersinia ruckeri in Rainbow Trout (Oncorhynchus mykiss).

This study was designed to appraise the effect of licorice herbal supplement on the immune status of rainbow trout fingerlings. Accordingly, five diets were formulated with different levels of licorice extract (LE) including 0 (control), 0.5 g kg-1 (LE0.5), 1 g kg-1 (LE1), 2 g kg-1 (LE2), and 3 g kg-1 (LE3). The fingerlings (10.0 ± 0.1 g initial mean weight) received the diets in triplicates (30 fish in each replicate) for 56 days. The results showed that the white blood cells and their differential number (lymphocytes and monocytes) were remarkably increased by LE2 supplementation (P < 0.05). The oral administration of LE2 significantly increased the levels of serum immunoglobulin (Ig), lysozyme activity, and complement components (C3 and C4) compared with others. Meanwhile, the serum bactericidal activity against Yersinia ruckeri in LE2 and LE3 treatments was significantly higher than others except for LE1 (P < 0.05). In addition, serum alternative complement activity significantly improved in all treated groups except LE0.5 compared with the control group (P < 0.05). In terms of skin mucosal immunity, the fish fed with LE2 and LE3 diets exhibited notably higher lysozyme activity, alkaline phosphatase activity, and Ig value than other groups (P < 0.05). The highest skin mucus bactericidal activity against Y. ruckeri was obtained in LE2 treatment (P < 0.05). In addition, dietary LE2 significantly increased the relative expression of immune-associated genes including tumor necrosis factor-α, interleukin-1ß, interleukin-8, and IgM and the former treatments showed higher values than the control group. The cumulative mortality of fish against Y. ruckeri infection was notably reduced from 53.6% in the control group to 29.0% in LE3 treatment. Overall, the dietary administration of LE at 2 g kg-1 had the best effects on immunocompetence in rainbow trout.

Folic Acid-Coated Nanochitosan Ameliorated the Growth Performance, Hematological Parameters, Antioxidant Status, and Immune Responses of Rainbow Trout (Oncorhynchus mykiss).

In recent years, chitosan has gained considerable attention due to its favorable properties such as excellent biocompatibility and biodegradability for which it can be used as a health supplement for delivering bioactive compounds in the food industry and nutrition. In the present study, the effect of nanochitosans coated with folic acid (FA) was considered on the growth performance, hematological parameters, antioxidant status, and serum immune responses of rainbow trout (Oncorhynchus mykiss) fingerlings. Graded levels of FA-coated nanochitosan (0, 0.1, 0.25, 0.5, and 1 mg kg-1 diet) were added to the basal diet, and each experimental diet was fed to three groups of fish with an approximate weight of 31 g for 8 weeks. The experimental study demonstrated that dietary FA-coated nanochitosan significantly (P < 0.05) improved the weight gain ration (WGR), specific growth rate (SGR), and feed conversion ratio (FCR) of fish at the end of the feeding trial. There were also linearly increasing trends in red blood cells (RBCs), white blood cells (WBCs), hemoglobin (Hb), and hematocrit (Hct) of fish fed with increasing dietary chitosan/FA levels, whereas no significant difference was recorded in differential leukocyte count of fish among the treatments. In case of antioxidant responses, fish fed diet supplemented with 0.50 mg kg-1 FA-coated nanochitosan had the highest CAT and SOD activities, while the maximum activity of GPX was found in fish fed diet supplemented with 1.00 mg kg-1 FA-coated nanochitosan. Malondialdehyde activity also reached the lowest value in fish fed with 1.00 mg kg-1 FA-coated nanochitosan-supplemented diet (P < 0.05). Measured immune responses showed a linear augmentation in lysozyme activity (LA) with increasing dietary FA-coated nanochitosan, while linearly and quadratically increasing trends were recorded in immunoglobulin M (IgM) content as well as complement component C3 and C4 activities by increasing the supplementation of nanochitosan coated with FA (P < 0.05). Findings of the current study illustrated the positive effect of dietary FA-coated nanochitosan as a promising compound on improving the growth performance, feed utilization, antioxidant status, and immune responses of rainbow trout.

Combined effects of enzymes and probiotics on hemato-biochemical parameters and immunological responses of juvenile Siberian sturgeon (Acipenser baerii).

A 10-week feeding trial was run to investigate the separate and simultaneous effects of exogenous enzymes (Enz), probiotics (Pro), and Pro-Enz mixtures on the hematology indices, serum biochemical parameters, and innate-immunity status of juvenile Siberian sturgeon. The fish (138.06 ± 3.64 g) were randomly dispersed into 12 tanks (20 individuals per tank) and fed with Enz (Phytase, protease, and xylanase), Pro (Pediococcus pentosaceus and Lactococcus lactis), and Pro-Enz cocktail. At the end of the feeding bioassay, the highest values of red blood cell count, hemoglobin concentration, hematocrit level, and lymphocyte percentage followed by the lowest neutrophil percentage were obtained in Pro-Enz treatment (P < 0.05). Despite a significantly lower level of alkaline phosphatase in the fish fed with Pro supplemented diet (P < 0.05), no significant difference was found in the serum level of alanine aminotransferase and aspartate aminotransferase among the experimental groups (P > 0.05). Total protein content was significantly upregulated in serum and skin mucus samples from those fed with supplemented diets compared to the control group (P < 0.05). In both serum and skin mucus samples, higher immune responses in terms of lysozyme activity, immunoglobulin M, total protein was seen in Pro-Enz treatment compared to the control group followed by the serum complement components (P < 0.05). The results indicate that the combinational supplementation of Siberian sturgeon diet with the exogenous enzymes and probiotics modulates the physiometabolic responses and innate immune system to a higher grade than their individual supplementation.

Stimulatory effect of dietary chasteberry (Vitex agnus-castus) extract on immunity, some immune-related gene expression, and resistance against Aeromonas hydrophila infection in goldfish (Carassius auratus).

Chasteberry is highly recommended as an herbal medicine across the globe for treating of many gynaecological disorders. In this study, chasteberry extract (CBE) was supplemented in goldfish diet to evaluate the immunity responses at the cellular and molecular levels. Moreover, after the feeding trial, the fish were challenged with Aeromonas hydrophila. The fish (300 individuals, 2.4 ± 0.12 g initial weight) were randomly distributed in 12 tanks and were fed with 0 (control), 5, 10, and 15 g CBE per kg of feed for 8 weeks. Based on the results, lysozyme activity, alkaline phosphatase, and total immunoglobulin (Ig) in the skin mucus samples were significantly enhanced in the fish fed with 15 g/kg CBE (P < 0.05). Moreover, dietary CBE positively affected lysozyme activity, complement components, and IgM content of the serum samples compared to the control group. Also, the number of monocytes and lymphocytes were increased significantly with increasing CBE in the diet (P < 0.05). The highest mRNA levels of tumor necrosis factors (TNF-α, TNF-2α) and Lysozyme were observed in 15 g/kg CBE treatment. After the challenge test, the highest relative percentage survival value (60%) was observed in the fish fed with 15 g/kg CBE. We concluded that dietary CBE especially at 15 g/kg has an immunomodulatory effect in goldfish by stimulating the innate immunity and some inflammatory cytokines as well as disease resistance against A. hydrophila.

Dietary peppermint (Mentha piperita) powder affects growth performance, hematological indices, skin mucosal immune parameters, and expression of growth and stress-related genes in Caspian roach (Rutilus caspicus).

Peppermint is a popular herbal medicine due to its several pharmaceutical applications. In this study, peppermint powder was used as a feed additive to evaluate growth performance, hematological parameters, protein profile of skin mucus, and immune parameters, as well as growth hormone (GH), insulin-like growth factor (IGF), and 70 kDa heat shock protein (HSP70) gene expression in Caspian roach (Rutilus caspicus). The fingerlings (average weight of 2.40 ± 0.12 g) were fed with diet containing 0 (control), 2, 3, and 4 g/kg peppermint for 8 weeks. The addition of peppermint significantly enhanced the growth parameters and decreased the food conversion ratio. Hematological indices of fish fed with peppermint-supplemented diets were significantly different from the control group (P < 0.05). Soluble protein, alkaline phosphatase, and lysozyme enzyme activity in mucus samples showed an incremental trend by increasing the peppermint levels in the diet. Evaluation of mucosal immunity indicated a remarkable difference between the protein profile in treatments fed with peppermint-supplemented diets and the control group. A new protein band (approximately 27 kDa) was also found in the skin mucus of fish fed with the diet containing 4 g/kg peppermint, and the highest band density was observed in this treatment. The highest IGF and GH gene expression were observed in 4 g/kg peppermint treatment. There was a significant difference in HSP70 expression between the fish fed with peppermint powder and the control group (P < 0.05). Overall, the results showed that dietary oral administration of peppermint at 4 g/kg of feed can act as a growth promoter and immunostimulant.

Effects of dietary chitosan and nano-chitosan loaded clinoptilolite on growth and immune responses of rainbow trout (Oncorhynchus mykiss).

In this study, rainbow trout Oncorhynchus mykiss weighing 27.75 ± 0.34 g were orally subjected to eight experimental diets each in three replicates containing varying amounts of chitosan and nano-chitosan (0.05, 0.5 and 5 g kg-1) loaded in clinoptilolite (14.28 g kg-1) for 70 days; and the growth and immune responses were evaluated. Results showed that growth parameters in fish fed diets chit + clin2, chit + clin3, nchit + clin1, nchit + clin2 and nchit + clin3 were significantly higher than in fish fed the control diet. All feeds, except chit + clin3, and nchit + clin3, significantly increased the total protein level. Feeds containing chit + clin2, nchit + clin1, and nchit + clin2 significantly elevated serum lysozyme activity compared with the control group. All treatments, except chit + clin3, and nchit + clin3 exhibited higher serum immunoglobulin (Ig) level than control one. In contrast, diet nchit + clin1 significantly unregulated the expression of Ig M gene in fish head-kidney compared to other groups. Additionally, all feeds, except clinoptilolite, and nchit + clin3, significantly improved the serum complement activity. Diets chit + clin2, nchit + clin1, and nchit + clin2 also significantly elevated antibacterial activity against Yersinia ruckeri compared with the control diet. Expression of inducible nitric oxide synthase (iNOS) gene in fish fed diets clinoptilolite, chit + clin1, chit + clin3, nchit + clin1, nchit + clin2, and nchit + clin3 was significantly higher than the control diet. All diets, except clinoptilolite, increased IL-1ß gene expression compared to the control group. Present results suggest that diets supplemented with nchit + clin, especially at 0.05 g kg-1 nano-chitosan inclusion, could improve growth performance and immune parameters of rainbow trout.

Biological nutrient recovery from culturing of pearl gourami (Trichogaster leerii ) by cherry tomato (Solanum lycopersicum) in aquaponic system.

The possibility of using different densities of cherry tomato as a bio-filter in a simple media-based aquaponic system to recycle nutrients from pearl gourami intensive culture wastewater was evaluated. Water quality parameters including total ammonia nitrogen (TAN), nitrite (NO2-), nitrate (NO3-), phosphate (PO43-), pH, and dissolved oxygen (DO) were determined in outlet of the aquaponic system during a 60-day experimental period. Cherry tomato was planted at four densities of 0 (control), 3 (T1), 6 (T2), and 9 (T3) plants per aquaponic unit with a constant fish stock density. Each treatment was equipped with aquaponic systems containing fish tank and plant growing bed. Productivity of the system was measured by recording the fish and plant growth indices. The potential in removing nitrogen of the water was the highest in T3 (with nine plants) compared to other treatments (p < 0.05). The highest concentrations of TAN (6.59 ± 0.241 mg/L), nitrite (0.42 ± 0.005 mg/L), nitrate (0.45 ± 0.162 mg/L), and phosphate (30.47 ± 0.371 mg/L) were obtained in control group, while the lowest concentrations of TAN (0.05 ± 0.091 mg/L), NO2- (0.11 ± 0.008 mg/L), NO3- (29.77 ± 0.205 mg/L), and phosphate (18.59 ± 0.185 mg/L) were detected in T3 (p < 0.05). The maximum fish weight gain was recorded in T3 (26 ± 0.014%) with 1.26 ± 0.059 FCR, and the lowest fish weight gain was measured in the control group (15 ± 0.024%) with 2.19 ± 0.446 FCR (p < 0.05). Total plant length gain was reached at the maximum value in T3 (74.70 ± 1.153 cm) in comparison to other groups (p < 0.05). It was concluded that small-scale aquaponic growing bed system can be created a sustainable ecosystem which both the plant and fish can thrive and suitable for home-made production system.

The Effect of Replacing Fish Meal in the Diet with Enzyme-Treated Soybean Meal (HP310) on Growth and Body Composition of Rainbow Trout Fry.

The potential of enzyme-treated soybean meal powder (HP310) as fish meal alternative in diets for rainbow trout weighing 1.17 ± 0.3 g was evaluated for 60 days. Fish meal was replaced with HP310 at 25%, 50%, 75% and 100% of experimental diets. A control group was also considered. The results showed that diets containing 75% and 100% HP310 had significantly higher feed conversion ratio and lower feed intake, weight gain and specific growth rate compared to fish feed diets containing higher levels of fish protein ingredients (p < 0.05). Results suggested use of 50% HP310 in trout diet had a positive effect on growth performance (p < 0.05). All fish feed diets with HP310 had lower hematocrit, hemoglobin and red blood cells compared to the control group, but the differences between the control and the other treatments up to 75% HP310 replacement levels of diet (p > 0.05). However increasing in level of HP310 in the diet caused a significant increase of the white blood cells (p < 0.05). The fish fed with a diet totally replaced by HP310 showed the highest values of ash and moisture content among the diets and showed significantly different levels when compared with the control and other feeding treatments (p < 0.05).