Nile Tilapia Fingerlings Research Articles

Dietary β-mannanase supplementation decreases digesta viscosity, improves growth and modulates gut microbiota in juvenile Nile tilapia, Oreochromis niloticus fed a soybean meal-based diet

β-mannan is an abundant non-starch polysaccharide (NSP) in soybean meal (SBM) that elevates digesta viscosity and decreases nutrient utilization in fish. This research aimed to evaluate the impacts of graded levels of dietary β-mannanase (BM) supplementation on growth performance, digesta viscosity, digestive enzyme activity, short-chain fatty acids (SCFAs) production, gut histomorphometry, and microbiome composition in juvenile Nile tilapia, Oreochromis niloticus, fed SBM-based diets (440 g kg−1). From a control diet containing 19 MJ kg−1 gross energy, 311.2 g kg−1 crude protein and 71.3 g kg−1 crude lipids, five BM-supplemented diets were made adding liquid BM (Natupulse® TS, Basf, Ludwigshafen am Rhein, Germany Germany) at either 1600, 3200, 4800, 6400, and 8000 TMU (thermostable endo-1,4-BM units) kg−1 to the control diet. Fish were hand-fed six times a day to apparent satiety for 8 weeks. Each experimental diet was fed to quadruplicate groups of 21 fingerling Nile tilapia (initial weight of 7.0 ± 0.43 g) stocked in 70-L aquaria connected as a closed recirculating system. Based on quadratic regression analysis of body weight gain (BWG) the optimal dietary BM was estimated at 4821 TMU kg−1. Fish fed the diet with BM at 4800 TMU kg−1 showed higher feed efficiency ratio (P < 0.001), activity of amylase (P < 0.001; +12.7 μm g−1) and lipase (P < 0.001; +1.6 μm g−1) enzymes, and reduced digesta viscosity (P < 0.001; −0.88 cP (cP)) compared to fish fed the control diet. Additionally, dietary BM at 4800 TMU kg−1 also increased butyric acid content (P < 0.001; +0.31 nmol L−1), reduced gut pH (P < 0.001; −0.65), and increased villus height (VH; P < 0.001; +13.8 μm) relative to fish fed the control diet. Analysis of the “core microbiota” revealed that dietary BM modulated gut microbiota of juvenile Nile tilapia with fish fed the diet containing 4800 TMU kg−1 showing higher abundance of the beneficial bacteria, Proteobacteria, Actinobacteria, and Firmicutes, and a reduced population of potentially harmful bacteria (Escherichia sp.) than fish fed control diet. In summary, including BM at a level of ≥4800TMU kg−1 in SBM-based diets showed multiple beneficial effects on juvenile Nile tilapia growth performance, energy and nutrient utilization, and gut health, promoting improved gut histomorphometry and abundance of beneficial bacteria and reducing potentially harmful bacteria. These findings highlight the potential of BM supplementation as an advanced nutritional tool to enhance growth performance and gut health of juvenile Nile tilapia fed SBM-based diets.

Mitigating Aflatoxin B1-Induced Growth Impairment and Hepatic Stress in Nile Tilapia (Oreochromis niloticus): Comparative Efficacy of Saccharomyces cerevisiae and Silicate-Based Detoxifiers.

The objective of this study was to detect the effects of acute aflatoxin B1 (AFB1) exposure in Nile tilapia (Oreochromis niloticus) and the effectiveness of Saccharomyces cerevisiae and silicate in reducing these effects. Two hundred and forty Nile tilapia fingerlings (16 ± 0.5g) were randomly assigned to four experimental groups, each with 60 fish and three replicates. Control basal diet (Diet 1) and three test diets were formulated, where Diet 2 was supplemented with 200ppb AFB1. Diets 3 and 4 were intoxicated with AFB1 (200ppb) and supplemented with 0.5% S. cerevisiae or 0.5%, respectively. After 60days, Diet 1 had considerably greater growth characteristics than the other groups (p < 0.05). Diet 2 revealed a reduced (p < 0.05) survival rate after 1month of exposure. In addition, Diet 1 showed higher (p < 0.05) total protein and albumin levels than Diets 3 and 4. AFB1 residues were detected in the liver in fish-fed Diet 2, Diet 4, and Diet 3. Alanine aminotransferase, aspartate aminotransferase, creatinine, and urea levels increased (p < 0.05) in fish-fed Diet 2. The glutathione peroxidase, lysozyme, and catalase activity were decreased (p < 0.05) in the fish-fed Diet 2. The malondialdehyde level was significantly higher in fish given Diet 2 (p < 0.05) than in fish-fed Diets 3 and 4. Histopathological investigation of fish-fed Diet 2 revealed impaired liver and spleen; however, both treatments (Diets 3 and 4) successfully lowered inflammation and preserved liver and spleen integrities. In conclusion, AFB1 impaired growth performance and posed a severe health risk to Nile tilapia. Furthermore, S. cerevisiae alleviated the contamination of AFB1 effects more efficiently than silicate employed for toxin adsorption.

Impact of Sel-Plex® dietary supplementation on growth performance, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia (Oreochromis niloticus) fingerlings challenged with Aeromonas hydrophila.

Organic selenium (Sel-Plex®) supplementation holds considerable promise for improving the effectiveness of fish production. This experiment was accomplished to judge the potential benefits of Sel-Plex® nutritional additive on growth outcomes, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia (Oreochromis niloticus) fingerlings exposed to bacterial infection with Aeromonas hydrophila. Utilizing a basal diet of 30% protein, four experimental diets were prepared, each of which contained Sel-Plex® at concentrations of 0.0, 0.5, 1, and 2 mg/kg, respectively. Three replicates of 20 fish/treatment were used using 240 healthy Nile tilapia fingerlings. Fish were placed in 12 glass aquariums and separated into 4 groups at random. For the entire span of 8 weeks, diets were admitted to fish at a 3% rate of fish biomass/aquarium. After the feeding trial, pathogenic A. hydrophila was intraperitoneally injected into fish of each treatment, and fish were observed for 15 days to track the survival rate (SR) after the challenge. Growth performance, physiological response, immunological parameters (phagocytic activity, phagocytic index, and lysozyme), and antioxidant parameters [catalase, superoxide dismutase (SOD), malondialdehyde, and glutathione peroxidase (GPx)] were noticeably improved in Sel-Plex® treated groups. Moreover, Sel-Plex® increased gene expression linked with the immune system in the liver (tumor necrosis factor-alpha and interleukin 1β), to growth (insulin-like growth factor 1 and growth hormone receptor), and antioxidants (SOD and GPx). Under pathogen-challenge conditions, the employed dietary Sel-Plex® supplementation could successfully lower fish oxidative stress, offering a potential preventive additive for Nile tilapia instead of antibiotics. On the other hand, Sel-Plex® significantly enhanced each of three intestinal morphological measurements (villus width, villus length, and crypt depth), demonstrating the greatest influence on the improvement of intestinal structure overall. In the Nile tilapia control group, the infection with A. hydrophila caused noticeable degenerative alterations in the gut, hepatopancreas, spleen, and posterior kidney. The severity of the lesion was significantly reduced and significantly improved with higher Sel-Plex® concentrations. Sel-Plex® supplemented groups had 100% SRs among the A. hydrophila-challenged groups. It could be advised to enrich the diets of Nile tilapia fingerlings with 1-2 mg.kg-1 of Sel-Plex® to enhance growth rate, physiological response, immunological reaction, and intestinal absorptive capacity.

Ameliorative effect of BIO-MOS® as a dietary supplementation on growth performance, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia (Oreochromis niloticus) fingerlings challenged with Aeromonas hydrophila.

Mannanoligosaccharides (MOS) usage in fish production has drawn more attention because of their positive benefits on disease resistance and fish performance. The ongoing research was executed to assess the potential advantages of Bio-Mos® dietary supplementation regarding the growth outcomes, physiological response, oxidative biomarkers, and immunity-linked gene expression in Nile tilapia (Oreochromis niloticus) fingerlings exposed to bacterial infection with Aeromonas hydrophila. Four experimental diets were developed using a 30% protein baseline diet, with Bio-Mos® added at variable levels; 0.0, 0.5, 1, and 2 g/kg, respectively. 240 healthy Nile tilapia fingerlings were split into 4 groups at random and assigned to 12 glass aquariums (three replicates of 20 fish/treatment). Diets were admitted at a 3% rate of fish biomass/aquarium for 8 weeks. Following the feeding trial, fish from every treatment were intraperitoneally injected with pathogenic A. hydrophila, and then observed for 15 days to record the survival rate percent (SR%) post challenge. Results revealed significant improvement in growth performance, physiological response, immunological parameters (phagocytic index, phagocytic activity, and lysozyme), and antioxidant parameters [catalase, malondialdehyde, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD)] among Bio-Mos® treated groups. Moreover, Bio-Mos® increased the expression of tumor necrosis factor alpha and Interleukin 1β, genes linked to the liver immune system. Growth-related genes (GHr), antioxidant-related genes (SOD and GSH-Px). In fish subjected to pathogens, dietary MOS supplementation could significantly lower oxidative stress, showing promise as a preventative supplement for Nile tilapia in place of antibiotics. On the other hand, Bio-Mos® considerably improved each of the three intestinal morphological measures (villus width, villus length, and crypt depth), showing the best overall intestinal structure-improving impact. The challenge with A. hydrophila caused marked degenerative alterations in the intestine, hepatopancreas, spleen, and posterior kidney of Nile tilapia, in the control group. However, lesion severity was greatly decreased and showed marked amelioration with an increased concentration of Bio-Mos®. The A. hydrophila-challenged groups revealed a 100% SR% mainly among the Bio-Mos® supplemented groups. It is recommended to enrich the Nile tilapia fingerlings diets with 2 g.kg-1 of MOS for better results on the growth rate, physiological response, immunological response, and intestinal absorptive capacity.

The Ameliorative Effects of Dietary Rosemary (Rosmarinus officinalis) Against Growth Retardation, Oxidative Stress, and Immunosuppression Induced by Waterborne Lead Toxicity in Nile Tilapia Fingerlings

Abstract The dietary effects of rosemary (Rosmarinus officinalis) leaves powder (RLP) were tested on the performance and welfare of Nile tilapia (Oreochromis niloticus) fingerlings subjected to lead (Pb) toxicity. Two hundred fish (31.9±0.28 g) were stocked into 20 85-L glass aquaria (10 fish/aquarium) to represent four treatments with five replicates each. Fish were fed on 0.0% (control; T1) and 1.0% RLP (T2) along with continuous exposure to either 0.0 (T3) or 7.94 mg Pb/L (T4) for 60 days. Compared with the control diet, feeding Nile tilapia on RLP alone improved the growth performance and hemato-biochemical, antioxidant, and immunological indices. Conversely, the Pb toxicity negatively affected hematocrit, hemoglobin, white and red blood cell counts, and growth indices. Furthermore, Pb exposure raised blood cortisol, glucose, total cholesterol, serum transaminases (ALT and AST levels), alkaline phosphatase, and lactate dehydrogenase accompanied with significant reductions in serum total lipids, protein, albumin, and globulin values. Furthermore, Pb exposure decreased respiratory burst, lysozyme, total immunoglobulins, malondialdehyde, superoxide dismutase, catalase, and total antioxidant capacity. On the other hand, dietary RLP significantly reduced the negative impacts of Pb toxicity on the above-mentioned indices. Additionally, the dietary RLP reduced the Pb accumulation in Pb-intoxicated fish leading to significant enhancements in Nile tilapia’s growth and welfare. These findings suggest that dietary 1% RLP significantly enhanced the fish performance and welfare status and could alleviate the Pb toxicity effects on Nile tilapia performance and welfare.

Dietary Nanozeolite Powder to Reduce Water Total Ammonia Nitrogen (TAN) and Improve Growth Performance and Plasma Biochemical Indices of Nile Tilapia (Oreochromis niloticus)

The effects of nanoscale synthetic zeolite powder (NZeP) levels in diet on water quality, growth performance, muscle proximate composition, and some blood biochemical indices of Nile tilapia (Oreochromis niloticus) fingerlings were evaluated in a 60‐day experiment. One hundred eighty fish with an average weight of 5.91 ± 0.45 g were distributed in three different groups of control (basal diet without NZeP), NZP0.5% (basal diet + 0.5% NZeP), and NZeP1% (basal diet + 1% NZeP) with triplicate. The zeolite particles were characterized via field emission scanning electron microscopy coupled with X‐ray energy dispersive spectroscopy (FE‐SEM/EDS), dynamic light scattering (DLS), and X‐ray diffraction (XRD) techniques. The results revealed that the total ammonia nitrogen (TAN) concentration in the NZeP dietary groups decreased compared to the control group after the 20th day of the experiment (p &lt; 0.05). The TAN concentration in the NZeP1% group was lower than in the NZeP0.5% group on days 50 and 60 (p &lt; 0.05). The final weight, weight gain, and average daily gain parameters were lower in the fish fed on NZeP1%‐supplemented diet than in other dietary groups (p &lt; 0.05). The feed conversion ratio value decreased in the NZeP dietary groups compared to the control (p &lt; 0.05). The lowest FCR value was recorded in the NZeP1% dietary group (p &lt; 0.05). The muscle crude protein content increased in the fish fed on diet supplemented with NZeP1% in comparison to the control (p &lt; 0.05). The aspartate aminotransferase (AST) concentration decreased in the plasma of fish fed on NZeP‐supplemented diets compared to the control (p &lt; 0.05). The plasma glucose concentration was lower in the NZeP1% dietary group than the control (p &lt; 0.05). In conclusion, the adding nanozeolite powder at a level of 1% to diet had positive effects on water quality, the growth performance, and muscle proximate composition of Nile tilapia fingerlings.

Immunological effects of vitamin c and zinc on tilapia (Orechromis niloticus) exposed to cold water stress.

This study investigates the immunological and growth effects of Vitamin C and Zinc supplementation on Nile tilapia (Oreochromis niloticus) subjected to cold water stress. Nile tilapia fingerlings were housed in eight 20-gallon tanks at Purdue University, acclimated to 26 ± 2°C water conditions before the experiment. The tilapia was divided into groups with varying water temperatures and feed supplements: control fish in warm water, and experimental groups in cold water with increased levels of Vitamin C and Zinc. Stress was induced by lowering the water temperature to 15 ± 2°C in four tanks, while the remaining tanks were kept at the optimal growth temperature. Results demonstrated that Vitamin C and Zinc supplementation significantly enhanced immune response and muscle regeneration in cold-stressed tilapia, allowing them to achieve growth rates comparable to those of control fish in optimal warm water conditions. These findings highlight the potential benefits of combined Vitamin C and Zinc supplementation in improving the immune response and growth performance of tilapia under suboptimal temperature conditions.

The impact of dietary probiotic supplementation on welfare and growth performance of Nile tilapia (Oreochromis niloticus).

The usage of commercial probiotic products as alternatives to traditional antibiotics in fish culture is initiated to be a potential factor for Nile tilapia fish's welfare and growth. The purpose of the current study is to show the influence of commercial probiotics (Bacillus amyloliquefaciens) dietary supplementation at different levels on Nile tilapia welfare and growth. Apparently healthy fingerlings of Nile Tilapia with a total number of 120 with an average initial weight (26.2 ± 0.3 g) were distributed into four groups (each group had 30 fingerlings). The first group (G1) was given a basal diet without additional probiotics, while other groups [second group (G2), the third group (G3), and the fourth group (G4)] were given basal diets supplemented with different levels of commercial probiotics (1 g, 2 g, and 3 g of probiotics per kilogram of diet), respectively (15 fish in each sub group as replicate), in eight glass aquaria (30 × 40 × 100 cm) for 2 months as an experimental period. The results revealed that the probiotic-treated groups especially G4 (3 g probiotics/kg diet) showed a marked increase in the following behavioral patterns such as feeding and swimming behaviors, while G2 (1 g probiotic/kg diet) had an increase in the foraging behavior compared with G1 control group. While surfacing, body care, and aggressive behaviors with all patterns were the highest in the control group (G1) than all probiotics-treated groups. The crossing test showed that fish rose in the probiotic-treated groups (G3 and G4) were more active and could achieve the highest growth rates. While water quality was better in G4 (3 g probiotic /kg diet) than in other groups. Moreover, G4 (3 g probiotic/kg diet) showed a marked increase in all serum biochemical parameters than the control group (G1). The current study proved that the best level of commercial probiotics (B. amyloliquefaciens) was (3 g probiotic/kg diet) for achieving optimal Nile tilapia fingerlings' growth performance under these experimental conditions. Finally, this work confirms the significance of the addition of probiotics as a feed additive to enhance both growth performance and immunity response, improve water quality, and achieve the welfare of Nile tilapia fingerlings.

Incorporation of Silk Warm By-Products Feeds as Un-Traditional Source of Protein in Diets of the Nile Tilapia (Oreochromis niloticus) Fingerlings

Incorporation of Silk Warm By-Products Feeds as Un-Traditional Source of Protein in Diets of the Nile Tilapia (Oreochromis niloticus) Fingerlings

Effects of Different Salinity Levels on Performance of Nile Tilapia Fingerlings in a Biofloc Culture System

Abstract Especially in arid regions, developing tilapia culture with the ability to survive a wide range of salinities is crucial due to the limited availability of fresh water for aquaculture. The present study focused on evaluating the growth performance of Nile tilapia in a biofloc system under three salinity levels: 0 (BFT0), 4 (BFT4), and 8 g/L (BFT8). Fingerling fish were raised for 37 days in tanks with a water volume of 140 liters and a stocking density of one fish per liter. The results of the water quality parameters showed that dissolved oxygen and pH decreased with increasing salinity. Furthermore, the BFT8 group had the highest concentrations of settled solid (19.98 ml/L) and total suspended solid (428.37 mg/L), while the BFT8 group had the lowest TAN concentration (4.32 mg/L). The final weight and specific growth rate were significantly higher in the BFT8 and BFT4 groups compared to the BFT0 group. Survival rates were not significantly different across treatments, and all of them were higher than 97%. The protein and lipid content of Nile tilapia bodies and bioflocs decreased with increasing salinity, while the ash content increased. The highest body ash content in Nile tilapia (13.81% of dry weight) and bioflocs (31.78% dry weight) was found at 8 g/L salinity. Based on the present study, it is suggested that salinities of 4 and 8 g/L can improve water quality, growth performance, survival, and carcass composition of Nile tilapia fingerlings in the biofloc system. This finding suggests that brackish waters can be utilized for sustainable aquaculture for the rearing of Nile tilapia.

Oregano Leaf Extract Dietary Administration Modulates Performance, Redox Status, Intestinal Health, and Expression of Some Related Genes of Nile Tilapia (Oreochromis niloticus L.)

Abstract The main objective of the current trial was to evaluate the beneficial influences of Origanum vulgare leaf extract (OVLE) on growth, some blood indices, redox status, and the expression of some growth and immune-related genes. Three thousand seven hundred and eighty Nile tilapia fingerlings were allocated to six equal groups. The first group served as a control and received a basal diet, while the other five groups were fed diets containing graded amounts of OVLE (0.1, 0.2, 0.3, 0.4, and 0.5%, respectively) and defined as OVLE0.1, OVLE0.2, OVLE0.3, OVLE0.4, and OVLE0.5 for 98 days. Growth performance and feed efficiency parameters were significantly improved in OVLE0.4 and OVLE0.5 groups compared with the control group. The hematological indices, specifically hemoglobin, red blood cell, and white blood cell count were significantly increased in the fish group fed a 4% OVLE-supplemented diet compared to other groups. Fish fed higher dietary inclusion levels of OVLE significantly increased total protein and albumin concentrations compared to other experimental groups. The OVLE0.4 and OVLE0.5 supplemented groups promoted innate immune response and phagocytic activity and stimulated the lipase enzyme activity of Nile tilapia. All estimated redox markers were significantly improved in the fish groups that received 4 or 5% OVLE compared with the control and other OVLE groups. The fish groups fed higher levels of OVLE significantly upregulated the expression of GH, IL-8, and IL-1β genes and downregulated the expression of the Hsp70 gene. Furthermore, the intestinal histological features demonstrated normal structure in all OVLE-administered fish groups, with improved intestinal villus length compared to the untreated group. Finally, it could be concluded that including OVLE in the Nile tilapia diet at higher levels (0.4 up to 0.5%) could improve performance and general health status.

Productive Performance and Serum Biochemical Parameters of Nile Tilapia Fingerlings Fed on Different Dietary Carbohydrate: Protein Ratios with Biotin Supplementation

The current experiment evaluated the effects of different dietary carbohydrate: protein ratios (CHO: CP ratio) without or with biotin supplementation on the growth performance, body composition, serum biochemical parameters and intestinal morphology in Nile tilapia. Fingerlings were assigned to 6 treatments arranged as following; Group 1 (G1) fed the basal diet (BD) with a medium CHO: CP ratio (47:32); G2 with high CHO: CP ratio (57:21); G3 with low CHO: CP ratio (36:42); while G4, G5 and G6 had the same previous experimental design of the first 3 groups but with biotin supplementation (0.06 mg/kg diet). The growth performance was only assessed for the first 6 weeks, then the experiment continued to 4 months and ended by sampling for other parameters determined. Fish feeding on high CHO: CP ratio (57:21) significantly reduced the fish body weight, gain and feed intake (FI) (P ≤ 0.05), while improved the feed efficiency compared to the medium and low ratios. Biotin addition to the high or the medium ratios containing diets resulted in lower growth, increased FI and deteriorated the feed efficiency when compared to their control groups without biotin addition (P≤ 0.05). Different dietary CHO: CP ratios significantly altered tilapia body composition of nutrients (moisture, EE, and ash), serum parameters (glucose, triglyceride, LDL and VLDL) and the liver function enzymes (GPT and GOT) (P≤ 0.05). The relative mRNA expression of GHR and IGF was significantly upregulated in fish fed on the low and the high ratios containing diets respectively. In conclusion, feeding of the early fingerling of tilapia on the high CHO: CP ratio during the first 6 weeks of life resulted in lower growth, however, it showed a protein sparing effect. Supplementation of biotin (extra over the diet) was not recommended as it showed adverse effects on tilapia growth especially during the first periods of life, however it showed some beneficial effects on alleviating the high-dietary carbohydrate-induced effects. Feeding on medium CHO: CP ratio (47:32) or low ratio (36:42) would be recommended during the fry and early fingerling stage of tilapia while the high ratio (57:21) would be beneficial in the diet of late fingerlings or adult tilapia.

Analysis of Achyranthes aspera leaf extract and acute toxicity study on fingerlings of Nile tilapia, Oreochromis niloticus

Schistosomiasis is a debilitating chronic disease with great socioeconomic and public health impact affecting the poor rural populations who lack access to sanitation, and safe water supply. The high cost of synthetic molluscicides, their toxicity to non-target organisms, and their persistence in the environment have forced the research of plant-derived molluscicides. Although plant molluscicides are cheap, biodegradable, ecofriendly and less toxic to higher animals, unregulated applications could affect non˗target organisms. Therefore, ecotoxicological studies are essential to assess the toxicity of these substances to economically and ecologically significant fish species and to establish safe dosage level. This study is intended to investigate the acute toxicity of a molluscicidal plant Achyranthes aspera to Nile tilapia fingerlings, Oreochromis niloticus (O. niloticus) (n = 7) were exposed to serial dilutions of A. aspera leaf aqueous extract using maceration method for 96 h in triplicate setup. Phytoconstituents were identified by GC-MS. Mortality data were analyzed by probit regression to determine lethal concentrations. The NOAEC was ascertained through hypothesis testing based on survival data. The respective piscicidal LC1 and LC10 values were 897.43 and 1063.87 mg/L while the LC50 is 1310.74 mg/L. In addition, the NOAEC was 1100 mg/L (p > 0.05). This piscicidal toxicity is much lower than its molluscicidal potency may be due to the presence of rotenones and triterpenoides which are commonly found in piscicidal natural products. The GC-MS analysis revealed 12 phytoconstituents including a monoterpene. This study indicates that A. aspera has low toxicity to Nile tilapia could be due to monoterpenes are nontoxic. The findings of this study demonstrate that, at this dose, the plant is safe to the test fish. Thus it can be effective, eco-friendly and sustainable alternative for the development of molluscicides for snail control.

The protective efficacy of dual dietary rosemary plus cinnamon mix against lead nitrate-induced immune suppression, genotoxicity, and oxidant/antioxidant status in Nile tilapia fingerlings

Lead (Pb) is a common heavy metal, which negatively influences the health and performance of aquatic organisms. The aquatic pollution with Pb is increasing day after day due to the increase in human activities, agricultural, and mining activities among others. Lead was regarded as oxidative stressor causing mutagenic and physiological disorders in aquatic animals. Hence, the current perspective assessed the promoting effects of dietary mixture of rosemary plus cinnamon (R + C) intervention on growth, hemato-biochemical, and hepatic oxidative biomarkers in Nile tilapia (Oreochromis niloticus) exposed to a sub-lethal dose of lead nitrate (7.94 mg Pb/L) for 60 days. Fish were distributed into four equal groups; T1 was kept as a control group, T2 was fed on 10 g R + C/kg feed, and T3 and T4 were fed on the control diet and 10 g R + C/kg feed, respectively, along with lead nitrate exposure. Findings of the present study indicated that, upon exposure to Pb (T3), growth, hemato-biochemical, and immune indices in Nile tilapia were notably reduced compared with that of the control group (T1). Meanwhile, stress (blood glucose, cortisol, total cholesterol, lactate dehydrogenase, alanine and aspartate aminotransferase, and alkaline phosphatase), hepatic oxidative stress (superoxide dismutase, catalase, and glutathione peroxidase) biomarkers, and DNA fragmentation percentage were significantly augmented in T3 vs T1. Additionally, exposing fish to lead nitrate caused immune suppression compared with the control group (T3 vs T1). On the other hand, the dietary supplementation of R + C mix to Nile tilapia (T2) enhanced its growth performance, antioxidant, and immune status. Feeding Pb-intoxicated Nile tilapia on R + C mix (T4) mitigated the oxidative damage and immune suppression induced by lead nitrate exposure compared with T3. Based on the present study outcomes, we opine that feeding Nile tilapia with rosemary plus cinnamon mixture (10 g/kg feed) has protective effects against lead nitrate-induced stress, physiological alterations, and oxidative damage.

Dietary effects of microalga Tetraselmis suecica on growth, antioxidant-immune activity, inflammation cytokines,and resistance of Nile tilapia fingerlings to Aeromonas sobria infection.

The dietary effects of the green microalga Tetraselmis suecica (TS) on the growth, digestive enzymes, immune and antioxidant responses, genes expression,and disease resistance of Nile tilapia (Oreochromis niloticus) fingerlings were investigated. This microalga was mixed with the diet'ingredients at doses of 0.0 (the control), 5, 10, 15,and 20 g/kg diet and then fed to fish daily for 84 days. After the feeding trial, fish were experimentally challenged with Aeromonas sobria, infection and fish mortalities were recorded for another 10days. Dietary TS significantly (p < 0.05) enhanced growth, digestive enzymes activities,and blood proteins, particularly at the level of 15 g/kg diet. Feeding the fish on 15 TS/kg feed exhibited highest mRNA expressions of GH and IGF-1 genes as well as SOD, CAT,and GPx genes compared to other TS groups. Moreover, highest levels of hepatic antioxidant and immune indices were found in the treatment of 15 g TS/kg feed. Significant downregulation of IL-1β and IL-8 genes expression and significant upregulation of IL-10 gene expression were observed in TS-fed fish, principally in fish groups fed on 15-20 g TS/kg feed. Conversely, hepatic malondialdehyde levels, blood glucose,and the activities of transaminases (ALT and AST) were significantly (p < 0.05) decreased in fish fed with 15-20 g TS/kg diet. Serum bactericidal activity against A. sobria was significantly higher in TS-fed fish groups, and its highest levels were found in treatments of 15-20 g/kg diet. Of interest, the survival rates of fish groups fed diets with 10-20 g TS/kg feed were higher after the challenge with A. sobria infection than the control group. Accordingly, we can conclude that supplementing fish diets with a 15 g TS/kg diet enhanced the growth, antioxidant and immune activities,and resistance of Nile tilapia fingerlings to possible A. sobria infection.

Nano-liposome of thyme essential oil promotes growth performance, antioxidant and immune responses to aeromonad septicemia in Nile tilapia, Oreochromis niloticus, fingerlings

Nano-encapsulation protects essential oils and increases their efficiency, compared to bulk forms. Hence in the present study, four diets (328 g/kg crude protein and 4402 kcal/kg gross energy) containing 0 (CTL), 25 mg/kg (25TV), 50 mg/kg (50TV), and 100 mg/kg (100TV) thyme, Thymus vulgaris, essential oil nano-liposomes (TV-NP) were offered to Nile tilapia fingerlings (initial weight of 4.27 ± 0.05 g) at water temperature of 26.46 ± 0.43°C, followed by intraperitoneal infection by Aeromonas hydrophila. Three hundred and sixty healthy fish were stocked in 12 tanks (60 L), 30 fish per tank, with daily water renewal rate of 40%. Each diet was offered to three tanks for 70 days. The fish were sampled at the end of feeding period and 12 h after the bacterial challenge. Compared to CTL, 50TV and 100TV treatments exhibited significant elevations in growth rate (14-17%; P&amp;lt;0.001), intestinal activities of amylase (9-19%; P=0.004), lipase (13-26%; P&amp;lt;0.001), protease (20-23%; P=0.001), and post-challenge survival (26-27%; P=0.001). Plasma lysozyme (14-15% P&amp;lt;0.001) and complement (5.1-5.4%; P=0.004) activities significantly increased in 25TV and 50TV, but decreased (lysozyme: 19%, complement 5.9%) in 100TV before the challenge; however, all TV-NP treatments showed similar lysozyme and complement activities after the challenge that were higher than CTL. 50TV and 100TV treatments also showed a decrease in lipid peroxidation (23-26%; P&amp;lt;0.001) and highest glutathione peroxidase activity (17-18%; P=0.001) and pre-challenge superoxide dismutase (21%; P=0.046) and catalase (15-17%; P=0.001) activities. Expression of tumor necrosis factor-alpha (11-fold, P&amp;lt;0.001), inerleukin-1 beta (5-fold, P&amp;lt;0.001), and transforming growth factor-beta (31-fold; P=0.001) in head kidney significantly increased in 100TV before the challenge. After the challenge, the transcripts of the cytokines significantly increased in all treatments and the highest expressions were observed in 50TV and 100TV treatments (62-148-fold). In conclusion, dietary 50-100 mg/kg TV-NP can be considered as a new feed additive in tilapia culture, as it improves growth rate, antioxidant capacity, and disease resistance in the fish.

Utilization of Black Soldier Fly (Hermetia illucens) Larvae as a Potential Substitute for Fish Meal in the Production of Nile Tilapia (Oreochromis niloticus L.)

Utilization of quality aqua-feed relies heavily on fish meal sources of protein because of its nutritional balance. However, due to its limited supply, high cost, and decline of wild fish populations, aquaculture production has shifted focus to cheaper and more readily available alternatives to guarantee sustainable aquaculture productivity. Black soldier fly (Hermetia illucens) larvae are a promising replacement for fish meal in fish diets due to their relatively high crude protein, lipid and mineral contents, and the bioactive potential with anti-microbial, and other probiotic properties. This study determined the effect of partially replacing fish meal with black soldier fly meal (BSFLM) on the growth performance of Nile tilapia (Oreochromis niloticus). Four isonitrogenous (30% crude protein) diets in which fish meal protein was gradually substituted with BSFLM were prepared as follows: No BSFLM (control)-T0; 25% (BSFLM25)-T25, 50% (BSFLM50)-T50 and 75% (BSFLM75)-T75. The feeds were fed to the Nile tilapia fingerlings (mean weight 25 &amp;plusmn;5 g) which were randomly stocked in 12 cages at a stocking density of 30 fish per cage. The experimental fish were manually fed at 3% of the body weight for 28 days, and 4% of the body weight for 154 days twice a day. The study found that 25% and 50% replacement of fish meal protein with BSFLM resulted in the best growth performance of Nile tilapia, as measured by final mean body weight gain (BWG), specific growth rate (SGR), feed conversion ratio (FCR) and condition factor (K). This suggests that BSFLM is a promising alternative to fish meal in aqua-feeds in the production of Nile tilapia.

Growth Performance and Biochemical Composition of Nile Tilapia (Oreochromis niloticus) Reared in Membrane Bioreactor Treated Wastewater

The aquaculture sector in Africa has great potential for growth; however, it faces several challenges, one of them being the scarcity of clean water. This prompts the need for water recycling. The present study was conducted to investigate the effects of rearing Nile tilapia (Oreochromis niloticus) using municipal wastewater treated with membrane bioreactor (MBR) technology. A total of 270 Nile tilapia fingerlings (0.15&amp;plusmn;0.05 g) were reared in three treatment groups in triplicate. There were 2 treatments, including; MBR treated wastewater and stabilization pond treated wastewater (maturation pond), while the municipal tap water was used as the control. The growth performance (weight and length) of the fish was monitored over a 24-week period. After the experimental period, the biochemical composition of the fish muscle was analysed using standard AOAC methods. The results showed that the highest weight gain, length gain, survival rate, and specific growth were obtained in the fish in the control followed by the MBR treatment. Additionally, the crude protein, as well as the crude fiber and dry matter, were significantly higher in the fish in the maturation ponds at 23.10%, 0.29%, and 25.35%, respectively, while the crude ash was highest in the MBR at 1.22%. Results also showed that the MBR and maturation pond treatments meet the permissible levels for BOD, COD, NH4, and NO3 for water to be used in aquaculture. The bioaccumulation of heavy metals in the fish was mainly from the feed, with copper being the highest contaminant at 1.75 mg/100 g. In conclusion, both the MBR and maturation pond treated wastewater are viable for use in the rearing of Nile tilapia without adverse effect on the growth. However, MBR treatment showed better growth performance, suggesting that it could be used to increase productivity in fish farming.

Dietary propolis improves the growth performance, redox status, and immune response of Nile tilapia upon a cold-stress challenge.

The purpose of this research was to demonstrate the potential of adding propolis (PR) to the diet of Nile tilapia (Oreochromis niloticus) to mitigate the harmful effect of cold stress (CS) on the growth performance, redox status, and immunological response. Two trials were conducted in this study. First, 210 Nile tilapia fingerlings (28.61±0.20 g) were used in a preliminary trial to determine the appropriate PR level and supplementation period to be applied for the main trial. Fish were assigned into 7 treatment groups (3 aquaria replicates × 10 fish per aquarium in each treatment group) according to the rate of PR supplementation in the fish diets at 0, 2, 4, 6, 8, 10, and 12 g/kg for 6 consecutive weeks. The average body weight and body weight gain were determined weekly. It was found that PR supplementation at 10 g/kg in fish diet for 4 weeks was enough to obtain significant results on the growth performance of Nile tilapia. For the main trial of the present study, 480 Nile tilapia fingerlings (average weight 29.93±0.11 g) were distributed into randomized 2 PR × 2 CS factorial treatment groups (6 replicate aquariums containing 20 fish in each group). Fish of PR groups received a basal diet for a feeding period of 4 weeks, included with 10 g/kg PR (+ PR group) or without PR inclusion (- PR group). Fish of the CS groups were either challenged with cold stress at 18°C (+ CS group) or maintained at a temperature of 26°C during the feeding period (- CS group). The results showed that CS challenge significantly (p < 0.05) impaired the growth indices, redox status, and immune response in the challenged fish compared to the non-challenged fish. On contradictory, the inclusion of PR into fish diets enhanced (p < 0.05) the feed intake, growth indices, antioxidant enzyme activity, and immunological parameters. Moreover, PR treatment alleviated the CS deterioration of fish weights, specific growth rates, feed efficiency, antioxidant enzyme activity, lymphocyte proliferation, and phagocytosis activity and alleviated the elevated mortality, H/L ratio, and malondialdehyde levels by cold stress. It is concluded that the inclusion of propolis at 10 g/kg in the diet of Nile tilapia fish could be approved as a nutritional approach to enhance their performance, especially when stressed by low-temperature conditions.

Dietary inclusion of Pediococcus acidilactici probiotic promoted the growth indices, hemato-biochemical indices, enzymatic profile, intestinal and liver histomorphology, and resistance of Nile Tilapia against Aspergillus flavus

This study investigated the effect of probiotic Pediococcus acidilactici CNCM I-4622 on the water quality, growth indices, hematological parameters, biochemical profile, innate immunity (lysozyme (LYZ) and immunoglobulin M (IgM)), and antioxidant (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX)) and digestive enzymes activity, with reference to the intestinal and liver histology of Nile Tilapia (Oreochromis niloticus), as well as disease resistance against Aspergillus flavus. A field trial was carried out for 56 days in which Nile tilapia fingerlings (4.0 ± 0.3 g) were randomly distributed into three replicate concrete ponds which were subdivided into four treatment groups, receiving P. acidilactici CNCM I-4622 at 0 (T0), 2.0 (T1), 2.5 (T2), and 3.0 (T3) g/kg diet, respectively. The obtained results revealed a significant amelioration in growth, feed utilization, body composition, and blood profiles, including erythrocytes and leukocyte counts, hemoglobin, and hematocrit concentration in the probiotics-treated groups compared to the control group. Dietary P. acidilactici at 2.5 and 3 g/kg diets enhanced the digestive enzymes (amylase, lipase, and protease) relative to the control group (p < 0.05). Biochemical parameters (total protein and albumin levels, and globulin) were notably increased, meanwhile, total cholesterol and triglycerides were significantly decreased in T3 supplemented group with a marked decrease in the levels of AST and ALT. Nevertheless, the serum activity of SOD, CAT, and GPX enzymes as well as LYZ and IgM were increased by P. acidilactici at 2.5 and 3 g/kg relative to the control group (p < 0.05). Also, a markedly increased length of the intestinal villi was prominent in treated fish with P. acidilactici at 2.5 and 3 g/kg. Feeding P. acidilactici at 3 g/kg significantly decreased the cumulative mortalities after the A. flavus challenge. In conclusion, our results presented the beneficial effects of P. acidilactici as a potent probiotic on growth indices, feed utilization, antioxidant properties, gut and liver health, and fungal resistance of Nile tilapia.