Growth Performance Of Nile Tilapia Research Articles

Effects of a multi-strain Bacillus probiotic on the intestinal microbiome, haemato-immunology, and growth performance of Nile tilapia.

The study evaluated dietary supplementation with a feed additive composed of multi-strain Bacillus for Nile tilapia Oreochromis niloticus. In vitro and in vivo assays employing culture-based microbiological methods and metagenomics were performed. Additionally, the study assessed the haemato-immunology, intestinal microbiome, and growth performance of the animals. For this, 30 juvenile Nile tilapia were used in the in vitro assay and 180 (60 + 120) in the in vivo assays. In the in vitro assay, we found evidence of adhesion of the probiotic bacteria to the intestinal mucus of fish, corroborated in the 15-day in vivo assay, in which the count of B. licheniformis was significantly higher in fish fed with probiotic when compared to fish of the control group. Furthermore, in the 50-day in vivo trial, a metagenomic analysis provided evidence for the modulation of the intestine microbiome of Nile tilapia by dietary supplementation of the probiotic. In addition, there was an increase in species richness, higher abundance of potentially probiotic autochthonous species and a lower abundance of Aeromonas sp. when the animals were fed the supplemented diet. Finally, no significant differences were observed in growth performance and haemato-immunological analyses, suggesting no harm to fish health when the product was supplemented for 15 and 50 days. The in vitro results indicate that the multi-strain probiotics were able to adhere to the intestinal mucus of Nile tilapia. Additionally, a modulation of the intestinal microbiome was evidenced in the in vivo assay.

Evaluation of the effects of dietary cinnamaldehyde on growth and nutrient use in Nile Tilapia (Oreochromis niloticus)

Cinnamaldehyde is an active organic compound and an aromatic aldehyde substance found in cinnamon oil. It is a new feed supplement for animals that can improve growth, nutrient digestion and absorption, lipid use, and immunity. The present study evaluated the effects of dietary trans-cinnamaldehyde 98 % (CIN) on nutrient utilization, antioxidant capacity, and growth performance in Nile tilapia (Oreochromis niloticus). Juveniles used was weighing at about 19.77 ± 0.10 g received dietary CIN at different doses (0, 0.25, 0.5, 0.75, and 1.0 g/kg feed). The fish were maintained in a glass aquarium of 95 × 45 × 35 cm3 in size at a stocking density of 20 fish per aquarium and fed three times a day to clear satiation. Dietary carbohydrate digestion and absorption were significantly improved in fish fed 0.75 g/kg CIN, as indicated by increased amylase activity and glucose tolerance test. The latter was subsequently confirmed by increases in relative ir, glut4, hx and gs expression that indicated the increase in glucose absorption led to an increase in glucose utilization as an energy source and the synthesis of glycogen as an energy reserve. Interestingly, dietary CIN supplementation also resulted in the downregulation of fas, which facilitates the conversion of glucose to fatty acids, and the upregulation of cpt1a and hsl, indicating increased fatty acid oxidation for energy. CIN at a range of 0.5–0.75 g/kg improved the antioxidant status in the liver, as illustrated by elevated glutathione peroxidase and superoxide dismutase activities (both P < 0.05). Final weight, feed consumption, the specific growth rate, feed efficiency, and protein retention increased were significantly in all CIN groups, with the highest values reached in the 0.5 g/kg CIN (all P < 0.05). Based on a polynomial orthogonal analysis of the fish-specific growth rate, the optimum dosage of CIN inclusion is 0.42 g/kg.

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.

Sustainability of Growth Performance, Water Quality, and Productivity of Nile Tilapia-Spinach Affected by Feeding and Fasting Regimes in Nutrient Film Technique-Based Aquaponics

Aquaponic systems offer an innovative approach to sustainable agriculture, where the interplay between fish and plant cultivation can be optimized. The choice of feeding and fasting schedules plays a crucial role in system efficiency and overall productivity. This study aims to investigate the impacts of various feeding and fasting schedules on water quality, and the growth performance of Nile tilapia, Oreochromis niloticus fingerlings, and spinach productivity in an aquaponic system based on the nutrient film technique (NFT). O. niloticus fingerlings with an initial weight of 13.47 ± 0.14 g were randomly stocked at a density of 6 kg/m3, and spinach plants (Spinacia oleracea) were included. The study employed a completely randomized block design with five replications. Various water quality parameters were monitored, and the effects of different feeding/fasting schedules on fish and spinach were assessed. The data revealed significant differences (p &lt; 0.05) in water quality parameters, all of which remained within acceptable ranges for aquaponic systems. The one-day feeding/one-day fasting treatment resulted in reduced final body weight, weight gain percentage, and specific growth rate, compared to other treatment groups (p &lt; 0.05). Higher levels of glucose and plasma cortisol were observed in this treatment. Economic efficiency was highest in the daily feeding treatment (40.05%), with no statistical difference (p &gt; 0.05) observed in the group subjected to three-day feeding/one-day fasting (39.03%). Spinach yield varied significantly between treatments (p &lt; 0.05), with the daily feeding treatment recording the highest yield (2.78 kg/m2) and the one-day feeding/one-day fasting cycle having the lowest yield (1.57 kg/m2). The findings suggest that the three-day feeding/one-day fasting regime in an NFT-based aquaponic system results in efficient nutrient utilization, higher productivity, and profitability for Nile tilapia. Additionally, this approach supports marketable biomass production for spinach. Different feeding and fasting schedules have distinct effects on water quality, fish growth, and spinach productivity in aquaponic systems. The three-day feeding/one-day fasting schedule emerges as an effective strategy for optimizing resource utilization and increasing overall productivity.

Silybum marianum promotes growth, hepatic antioxidative activity, and splenic immunity but does not influence the intestinal barrier function of Nile tilapia, Oreochromis niloticus

Alternative additives such as phytobiotics have been a research priority to promote chemotherapeutic-free and disease-resistant aquaculture. Hence, various Silybum marianum (SM) extract levels, including 1, 2, 3, and 4 g kg−1, were supplemented with a reference diet, and the reference diet containing no SM was considered a control. Each test diet was fed in triplicate to experimental fish for 60 days. The effects were observed on growth, liver, lymphoid organs (kidney and spleen), and intestinal health in relation to a panel of blood biochemical responses of Nile tilapia, Oreochromis niloticus. Better growth performance in Nile tilapia fed any supplementation levels of SM resulted from improved feed utilization and feed conversion ratio. Microscopic observations found normal kidney, liver, and spleen microstructure across all treatments. Of interest, the antioxidative capacity of the liver was stimulated by SM supplementation, supported by higher expression of CAT, SOD, and GPx genes coupled with higher levels of hepatic GST and T-AOC and lower levels of hepatic MDA concentrations. This was further aligned with lower levels of serum ALP, AST, and ALT relevant to liver function. Meanwhile, splenic immune relevant gene expression (IFN-γ1, LYZ, and hepcidin) increased significantly in all SM-treated fish compared to the control group. Also, hematological responses, including red blood cell indices (RBCs, Hb, HTC, PCV, MCV, MCH, and MCHC) and white blood cell indices (WBCs, lymphocytes, eosinophils, basophils, and heterophils), except monocytes, were improved by SM supplementation. Intestinal microstructures were normal, and their barrier functions were unchanged by dietary supplementation. Hence, SM extract could be used as a promising avenue for enhancing the functionality of aquadiet, leading to improving overall health performance. However, the mode of action of the bioactive ingredients present in SM extract is warranted to be further studied to consider SM as a functional additive for aquafeeds.

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.

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.

Sex reversal using 17 α-methyltestosterone immersion and its effect on sex reversal and growth performance of Nile tilapia (Oreochromis niloticus L., 1758)

Sex reversal using 17 α-methyltestosterone immersion and its effect on sex reversal and growth performance of Nile tilapia (Oreochromis niloticus L., 1758)

Dietary grape seed proanthocyanidin extract improved the chemical composition, antioxidant capacity, myofiber growth and flesh quality of Nile tilapia muscle

The effects of dietary grape seed proanthocyanidin extract (GSPE) supplementation (0, 100, 200, and 400 mg/kg) on the stress response, antioxidant status, myofiber growth, and meat quality of Nile tilapia were investigated in present study. Dietary GSPE lowered serum stress-related parameters (cortisol, glucose, Na+, and lactate) and improved the total antioxidant capability with enhanced superoxide dismutase and catalase activities and reduced levels of reactive oxygen species. Meanwhile, myoglobin content, pH, color, tenderness, the water-holding capacity were improved. Dietary GSPE also increased the contents of delicious amino acids, flavor amino acids, and total amino acids, C18:3n-3 (ALA), C20:5n-3 (EPA), n-3 poly-unsaturated fatty acids, decreasing off-flavor compounds such as aldehydes and alcohols. Moreover, GSPE supplementation improved myofiber growth and muscle protein deposition likely via the activation of the IGFs/PI3K/Akt/TOR/S6K1/4E-BP1 pathway, contributing to the enhanced growth performance of Nile tilapia (Oreochromis niloticus). Together, GSPE is a promising natural food additive that enhances various important meat quality parameters of fish, and the optimal dietary GSPE requirement for maximum growth and muscle protein deposition was approximately 280 mg/kg.

Effects of Broad Bean Diet on the Growth Performance, Muscle Characteristics, Antioxidant Capacity, and Intestinal Health of Nile Tilapia (Oreochromis niloticus)

Four crisping diets were designed to conduct a feeding experiment to investigate the use of broad bean in the formulated feed of Nile tilapia and optimize its use. The growth performance, muscle characteristics, antioxidant capacity, and intestinal health of Nile tilapia with an initial body weight of 617.32 ± 1.64 g were evaluated after being fed with different diets for 90 days. The results showed no adverse effect on the growth performance of Nile tilapia fed with broad bean diets. Contrastingly, some improvements were found in WGR and SGR, but a lower FCR was obtained. The supplementation of broad beans weakened the antioxidant capacity of fish but did not influence liver health and the immune system. Increasing the amount of broad bean addition can increase muscle quality values, and an embrittling functional package being added to the diet can also improve muscle hardness, adhesiveness, and chewiness of Nile tilapia muscle. In addition, the crisping functional package can be applied to tilapia crisping formulated feed, which helps to improve the integrity of the intestinal tissue structure and optimize the intestinal microbiota of Nile tilapia. The final achievement of this study is to provide a theoretical reference for optimizing the breeding technology of crispy Nile tilapia and developing a specialized crisping diet for the species.

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.

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.

Effects of dietary Periplaneta americana water extract on growth, chemical composition, muscle antioxidant status, and meat quality of Nile tilapia

Abstract This study investigated the effects of dietary Periplaneta americana water extract (PAWE) supplementation (0, 1, 2, and 4 g/kg) on the chemical composition, antioxidant capacity, and meat quality in Nile tilapia. The results showed that the extract improved weight gaining rated of Nile tilapia (Oreochromis niloticus). Meanwhile, dietary PAWE decreased lactate content, glycolytic potential, centrifugal water loss, and cooking loss, and enhanced muscle pH, protein content, total sulfhydryl content and meat color in Nile tilapia muscle. Dietary PAWE also improved the total antioxidant capability with enhanced superoxide dismutase, catalase, and glutathione peroxidase activities and lowered contents of reactive oxygen species, and lipid and protein oxidation products (i.e. thiobarbituric acid reactive species and protein carbonylation). Moreover, dietary PAWE enhanced the contents of flavor amino acids, total amino acids, adenosine monophosphate, and 5′-inosine monophosphate with enhanced the taste indicators (umami, richness and sweetness). In addition, PAWE supplementation improved myofiber growth and muscle protein deposition likely by activating of the IGFs/PI3K/Akt/TOR/S6K1/4E-BP1 pathway, contributing to the enhanced growth performance of Nile tilapia. The optimal dietary PAWE requirement for maximum growth and muscle protein was approximately 3 g/kg. Together, PAWE is a promising natural food additive that enhances muscle quality and nutritional value of Nile tilapia.

Microencapsulation of Lactobacillus plantarum in the alginate/chitosan improves immunity, disease resistance, and growth of Nile tilapia (Oreochromis niloticus).

This study evaluated the effects of microencapsulation of L. plantarum (as a probiotic) with chitosan/alginate biopolymers (MLCA) on innate immune response, disease resistance, and growth performance of Nile tilapia (Oreochromis niloticus). Four hundred and eighty fish were randomly distributed in glass tanks (150 L) and fed with diets including diet 1: control; diet 2: 10 g kg-1 microcapsules; diet 3: 108 CFU g-1 L. plantarum; and diet 4: 10 g kg-1 MLCA for 60 days. The hematology and biochemical indices, lysozyme activity, alternative complement activities, respiratory burst, serum bactericidal activity, as well as growth performance parameters (specific growth rate, feed conversion ratio) were analyzed. White blood cells, plasma protein and globulin concentration, serum lysozyme, and respiratory burst activities of fish were significantly increased (P < 0.05) in the MLCA diet. A challenge test against Streptococcus agalactiae, at the end of the experiment, showed the highest survival rate of the fish fed with MLCA. Moreover, the fish fed with MLCA showed a significant improvement in SGR (3.12 ± 0.18%) and FCR (1.23 ± 0.20) and had the highest growth performance. These results suggest longer stability of probiotics in the microcapsules, and their immunomodulatory effect can be considered a promising immunostimulant and growth enhancer in the Nile tilapia diet.

Mitigation of cold stress in Nile tilapia (Oreochromis niloticus) through dietary lipids supplementation: a preliminary network meta-analysis.

There is a growing body of evidence suggesting that water temperature can significantly impact the dietary fatty acid requirements of Nile tilapia (Oreochromis niloticus). Therefore, this study assessed the effectiveness of different dietary lipid sources on the growth performance of Nile tilapia reared at suboptimal temperatures. A network meta-analysis was performed, including searches of PubMed and Scopus from inception to January 2022, for trials that evaluated the effects of lipid sources on cold-stressed Nile tilapia. The Bayesian hierarchical framework was used to pool and compare the effect sizes of growth parameters such as weight gain, feed intake, and feed conversion ratio (FCR). Furthermore, the surface under the cumulative ranking curve (SUCRA) was obtained to calculate the probability that each lipid source was the most effective against cold stress. All subsequent numbers refer to comparisons with diets containing only fish oil. Dietary Aurantiochytrium significantly increased weight gain (SMD = 2.00, CrI: 0.70 to 3.40). In contrast, diets containing coconut oil led to significantly lower weight gain (SMD = - 3.30, CrI: - 6.00 to - 0.63) and higher FCR (SMD = 17.0, CrI: 6.70 to 27.0). Additionally, dietary corn oil was associated with a decrease in feed intake (SMD = - 2.32, CrI: - 3.91 to - 0.80), while a combination of fish and corn oil reduced FCR (SMD = - 5.70, CrI: - 11.0 to - 0.81). In general, the analysis of SUCRA values revealed that in cold-stressed Nile tilapia, Aurantiochytrium, sunflower oil, and the combination of fish and corn oil were the most effective lipid sources for improving growth at suboptimal temperatures. The results of the current study can serve as a basis for future studies that focus on the use of dietary lipid sources to mitigate cold stress in Nile tilapia.

Effects of Oat Bran Addition on the Growth Performance and Intestinal Health of Nile Tilapia (Oreochromis niloticus) Exposed to Copper Ions.

This study investigated the effects of the oat bran addition on the growth performance and intestinal health of Nile tilapia (Oreochromis niloticus) exposed to copper ions. Four groups of diets containing 0%, 5%, 10%, and 20% oat bran were fed to Nile tilapia for four weeks. The results showed that oat bran had a dose-dependent effect on the growth performance of Nile tilapia. The addition of oat bran can increase the relative abundance of Delftia, which is capable of degrading heavy metals in the intestinal tract and alleviating the intestinal damage caused by copper ion stress. Compared to the control group, the 5% oat bran group had an increased intestinal antioxidant capacity. The relative gene expression of proinflammatory factors (NF-κB, IL-1β) was significantly downregulated in the 5% oat bran group (P < 0.05), and the relative gene expression of anti-inflammatory factors (TGF-β), HIF-1α, occludin, and claudin was significantly upregulated (P < 0.05). In conclusion, we suggest that 5% oat bran should be added to the diet to improve the growth performance of Nile tilapia and alleviate the negative effects of copper ion stress on intestinal health.

A single exposure to sub-lethal concentrations of a glyphosate-based herbicide or fluoxetine-based agent on growth performance in Nile tilapia

ABSTRACT The aim of the present study was to determine e whether a single acute 96 hr exposure of a glyphosate-based herbicide (GBH) to Nile tilapia fingerlings affected growth performance during the first 90 days of culture. This association was considered as GBH increases serotoninergic activity that affect fish anorexically. Although these findings were based upon chronic investigations, this study was designed to examine whether a single, acute, but excessive concentration GBH might impair growth performance in fish. In parallel, fish were also exposed to fluoxetine (FLU), a drug that selectively inhibits the reuptake of serotonin in brain synapses, leading to increased serotoninergic activity. Data demonstrated a decreased growth performance in fingerlings exposed to GBH or FLU compared to unexposed fingerlings. In fact, FLU-exposed fingerlings exhibited lower average weight and length, diminished weight gain, which resulted in lower final biomass. GBH-exposed fish, despite displaying a lower mean body weight, exhibited a biomass similar to biomass on controls. These body weight differences were noted after 30–60- and 90-day growth period in clean water. In an aquaculture context, these observed changes may be considered harmful to the production or economic performance of large-scale farming as currently practiced in tilapia farming.

Impacts of different levels of vitamin K on the growth performance, hematological parameters, and immunological response of juvenile Nile tilapia (Oreochromis niloticus)

The current investigation was carried out to determine the impacts of different levels of vitamin K (VK) on the growth performance, hematological parameters, and immunological response of all-male juveniles of Nile tilapia (O. niloticus). VK3 (menadione) was added in five concentrations (0.0, 2.0, 4.0, 8.0, and 12.0 mg kg–1 diet) in five isonitrogenous (30% cp), isocaloric (18.61 MJ kg–1) diets. The fish were fed the diets at a daily rate of 3% of their live weight, divided into 3 meals for 60 days. The results implied that supplemental VK did not provide any growth rate improvements and the efficiency of feed utilization over the control diet. Increasing dietary VK above 2 mg kg–1 feed resulted in significant retardation in fish performance and survival rates. Furthermore, supplemental VK up to 2–4 mg kg–1 increased hematological parameters, physiological functions, immune response, antioxidant capacity, and bone mineralization. Further increase in dietary VK resulted in a significant decline or level off in these parameters. Meanwhile, liver function enzymes increased progressively with dietary VK increasing. In conclusion, these findings suggest that supplemental VK maybe not be necessary for Nile tilapia growth performance, whereas about 2–4 mg kg–1 diet is required for other physiological functions. Increasing VK beyond these levels may pose adverse effects on Nile tilapia. However, further long-term studies are required to confirm these results.

Effect of an organic acid blend in Nile tilapia growth performance, immunity, gut microbiota, and resistance to challenge against francisellosis

Organic acids (OAs) are a class of feed additives that have prophylactic and inhibitory properties against pathogenic bacteria. In this study, we investigated growth performance, innate immune response, gut microbiota, and disease resistance against Francisella orientalis F1 in Nile tilapia (Oreochromis niloticus) fed different doses of Bacti-nil®Aqua, a blend of short- and medium-chain OAs. For 21 days, 680 juvenile tilapias were fed a control diet or diets supplemented with a 0.3% (D3) or 0.5% (D5) OA blend. The feed conversion rate of fish fed the 0.5% enriched diet was considerably lower (p < 0.05) than that of the fish fed the basal diet. Lysozyme and serum bactericidal activities were significantly elevated following OA administration. After infection, no differences in the diversity and composition of gut microbiota were observed between the groups. After the bacterial challenge, the mortality was significantly lower in group D5 (p < 0.01). The diet supplemented with Bacti-nil®Aqua (Adisseo) improved the immune response and resistance of tilapia juveniles against F. orientalis infection. Thus, this OA blend could serve as a feed additive with good activity against F. orientalis.

Application of limestone-molasses blends in Nile tilapia rearing tanks

The work aimed at determining the effects of applying different blends between liquid molasses and agricultural limestone on water quality and growth performance of Nile tilapia juveniles, Oreochromis niloticus. The study employed 24 indoor tanks of 100 L and 24 outdoor tanks of 250 L. Four control groups were set up (no product applied, only molasses, only limestone, molasses-limestone blend with 48% limestone but no fish) and two experimental groups (molasses-limestone blends with 32% and 48% molasses), with four replicates each. Over 11 weeks, the water quality was monitored systematically. The 24-h cycle monitoring of temperature, pH, specific conductance, dissolved O2 and total alkalinity were carried out at the 8th week. The blends between molasses and limestone accelerated the dissolution rate of the agricultural limestone in water. The blend containing 48% molasses led to greater increases in water alkalinity and pH in relation to tanks with only limestone applications. However, the molasses-limestone blend applications impaired the Nile tilapia growth performance, especially in the outdoor tanks. While the fish yield was 25.1 g m-3 day-1 in the molasses outdoor tanks, it was equal to 22.8 g m-3 day-1 in the molasses (32%)-limestone units (P&lt;0.05). It has been concluded that the blending between limestone and molasses brings no clear benefits to Nile tilapia’s rearing tanks when compared to the limestone-only tanks.