Tilapia Diets Research Articles

Overview on the role of dietary Spirulina platensis on immune responses against Edwardsiellosis among Oreochromis niloticus fish farms

Edwardsiellosis is a bacterial fish disease that mostly occurs in freshwater farms and is characterized by a high mortality rate. Edwardsiella tarda strain was recovered from 17 fish out of 50 Nile tilapia, which were harboring clinical signs of systemic septicemia. The level of un-ionized ammonia (NH3) in the fish farm’s water was 0.11–0.15 mg/L, which was stressful for the Nile tilapia.Sequencing of the gyrB1 gene confirmed that the isolate was E. tarda JALO4, and it was submitted to NCBI under the accession number PP449014. The isolated E. tarda harbored the virulence gene edw1 AHL-synthase (quorum sensing). In addition, the isolate was sensitive to trimethoprim and sulfamethoxazole mean while it was intermediate to florfenicol. The median lethal dose (LD50) of E. tarda JALO4 was determined to be 1.7 × 105 CFU/mL in Nile tilapia.In the indoor experiment, Nile tilapia (45.05 ± 0.4 g), which received dietary Spirulina platensis (5 and 10 g/kg fish feed), showed optimum growth and feed utilization. Meanwhile, after receiving dietary S. platensis, the fish’s feed conversion ratio (FCR) was significantly enhanced compared to the control, which was 1.94, 1.99, and 2.88, respectively. The expression of immune-related genes interleukin (IL)-1β and tumor necrosis factor (TNF)-α were upsurged in E. tarda-challenged fish with higher intensity in S. platensis groups. Dietary S. platensis at a dose of 10 g/kg fish feed could provide a relative protection level (RPL) of 22.2% Nile tilapia challenged against E. tarda. Nile tilapia experimentally infected E. tarda, drastically altering their behavior: higher operculum movement, low food apprehension, and abnormal swimming dietary S. platensis (10 g/kg fish feed) could rapidly restore normal status.It was concluded that Edwardsiellosis could alter Nile tilapia behavior with a high loss in fish population. Fish received dietary-S. platensis could rapidly restore normal behavior after E. tarda infection. It is recommended the incorporation of S. platensis at doses of 10 g/kg into the Nile tilapia diet to boost their immunity and counteract E. tarda infection.

Impact of Partial Substitution of Soybean Meal by Cottonseed Meal with Iron Sulfate Supplementation in Nile Tilapia Diet

Aquatic meals participate in food security and nutrition. The economic dimension greatly influences the sustainability of the aquaculture industry. This study aimed to assess the effects of partial substitution of soybean meal (SBM) with cottonseed meal (CSM) supplemented with ferrous sulfate (FS) on the growth performance and health status of Nile tilapia. One hundred and fifty Nile tilapia (Oreochromis niloticus) were split equally into five group (triplicated). Each group was fed one of the following isonitrogenous isolipid diet; diet1 (0% CSM), diet2 (20% CSM), Diets3 (20% CSM with 580 mg/kg (FS), diet4 (50% CSM), and diet5 (50% CSM with 580 mg/kg FS) of total protein for two months. In comparison to the control group, Statistically significant (p<0.05) improvements in growth performance, hemogram, and leukogram, as well as, the levels of ALT, AST, urea, creatinine, total protein, MDA, and GSH-px were observed in the third treatment . Histopathologically, it showed the highest values of villus height, width, and surface absorption area with normal architecture and cellular details. On the other hand, fish fed diet4 had the lowest growth rat with microcytic normochromic anemia and decreased villus height and width. The groups that fed CSM showed lower cholesterol levels. In conclusion, CSM inclusion with FS supplementation enhanced growth and health parameters.

Effects of dietary supplementation with benthic diatom Amphora coffeaeformis on blood biochemistry, steroid hormone levels and seed production efficiency of Nile tilapia Oreochromis niloticus broodstock.

Aquafeed additive quality and quantity remain pivotal factors that constrain the sustainability and progress of aquaculture feed development. This study investigates the impact of incorporating the benthic diatom Amphora coffeaeformis into the diet of Nile tilapia (Oreochromis niloticus) broodstock, on the blood biochemistry, steroid hormone (SH) levels and seed production efficiency. Broodstock females displaying mature ovary indications were initially combined with males at a ratio of three females to one male. A total of 384 adult Nile tilapia (288 females and 96 males) were used, with 32 fish (24 females and eight males) assigned to each of 12 concrete tanks (8 m³; 2 m × 4 m × 1 m), with three replicate tanks for each dietary treatment, throughout a 14-day spawning cycle until egg harvest. Fish were fed one of four different dietary treatments: AM0% (control diet), and AM2%, AM4% and AM6% enriched with the diatom A. coffeaeformis at levels of 20, 40 and 60 g/kg of diet respectively. At the trial's conclusion, total protein, albumin, triglyceride and creatinine), SHs (follicle-stimulating hormone, luteinizing hormone, free testosterone, total testosterone, progesterone and prolactin) and seeds production efficiency of Nile tilapia improved significantly (p < 0.05) in alignment with the increment of A. coffeaeformis supplementation. The findings propose that including A. coffeaeformis at levels ranging from 4% to 6% could be effectively employed as a feed additive during the Nile tilapia broodstock's spawning season.

Pichia kudriavzevii as feed additive in Nile tilapia (Oreochromis niloticus) diet.

Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their nutritional benefits. Despite their potential, marine and mangrove yeast species used in the aquaculture industry have received little attention in the Philippines. Pichia kudriavzevii (A2B R1 ISO 3), sourced from bark samples, was selected and mass-produced due to its high protein content and amino acid profile. The dried biomass of P. kudriavzevii was incorporated into the diets of Nile tilapia (Oreochromis niloticus) juveniles at varying inclusion levels (0, 1, 2, and 4g/kg diet) and its effect on their growth performance, body composition, and liver and intestinal morphology was assessed after 40 days of feeding. The groups that received P. kudriavzevii at a concentration of 2g/kg diet exhibited higher final body weight, percent weight gain, and specific growth rate in comparison to the other treatment groups. Whole body proximate composition did not vary among the dietary groups. Intestinal and liver histopathology also indicated no abnormalities. These findings suggest the potential of ascomycetous P. kudriavzevii as a beneficial feed additive in Nile tilapia diets, warranting further investigation into its long-term effects and broader applications in fish culture.

Fishmeal substitution by zooplankton or Daphnia magna biomass meals in the diet of Nile tilapia: Effectson growth, gut histological changes, bacterial abundanceand stress tolerance.

Fishmeal substitution with sustainable feed sources is highly essential towards sustainable production. This study aimed to investigate the effects of substituting fishmeal (FM) with Daphnia magna biomass meal (DBM) or zooplankton biomass meal (ZBM) on growth performance, liverand intestinal histology, gut bacterial abundanceand stress tolerance of Nile tilapia, Oreochromis niloticus, fry. Nile tilapia fry (0.23 ± 0.04 g) were randomly assigned to five groups of three replicates. The control diet comprised 300 g/kg FM, and the FM was substituted with DBM or ZBM at levels of 25% and 50% (DBM-25, DBM-50, ZBM-25and ZBM-50respectively) in the other experimental diets. The experiment lasted 56 days in 1.5 m3 concrete tanks. The results revealed that weight gain andfeed conversion ratio(FCR) significantly (p ≤ 0.035 and 0.025respectively) improved with a polynomial response with a peak at 25% ZBM and a linear increase with DBM up to 50% of FM. Histometric indices of the distal intestine showed improvements (p ≤ 0.001) in villus height, villus width, crypt depthand muscle thickness of fish fed DBM or ZBM compared to the control. In the meantime, there were no histological abnormalities in the liver sections. The replacement of FM with DBM or ZBM could modulated gut bacterial abundance, including total bacterial count, Escherichia coli, Bacillus subtilis, and Lactobacillus sp. The fish-fed DBM or ZBM-containing diets had higher (p ≤ 0.05) tolerances to salinity stress than the control group. In conclusion, DBM or ZBM could replace FM up to 50% and 25%, respectivelywith improved fish growth performance, FCR, gut histologyand tolerance to salinity stress.

The effects of dietary Spirulina platensis or curcumin nanoparticles on performance, body chemical composition, blood biochemical, digestive enzyme, antioxidant and immune activities of Oreochromis niloticus fingerlings

ContextRecently, prioritize has been given to using natural phytogenic or nano compounds as growth promoters and immunostimulants in fish diets as an alternative to antibiotics.AimsThe main propose of this trial was to determine the impact of supplementing diets with spirulina or curcumin nanoparticles on the performance and health indicators of Nile tilapia fingerlings.MethodsIn a 56-day feeding trial, 180 tilapia fingerlings were assigned into three main groups, as follows: 1st, control group, 2nd, Spirulina platensis (SP; 5 g kg-1 diet) and 3rd, curcumin nanoparticles (CUR-NPs; 30 mg kg-1 diet).Key resultsIncorporating tilapia diets with SP or CUR-NPs significantly improved performance, body chemical analysis, blood biochemical and hematological indices, digestive enzyme activities, and antioxidant and immunostimulant features compared to the control.ConclusionFortified tilapia diets with CUR-NPs or SP efficiently boost the productivity and health of Nile tilapia fingerlings.ImplicationsThe research introduces new practical solutions for applying safe feed additives as alternatives to antibiotics in tilapia farming.

Enhancing immune and antioxidant responses in Nile tilapia through dietary supplementation with Ulva fasciata extract: A study on gene expression and resistance to Aeromonas hydrophila.

The study focused on the impact of Ulva fasciata extract (UFE) supplementation in the diets of Nile tilapia (Oreochromis niloticus) on blood and biochemical markers, immune and oxidative responses, and the expression of related genes, with a specific interest in their condition following exposure to Aeromonas hydrophila. Four different levels of UFE were tested in the diets: 0% (0 mg kg- 1) for the control group (U0), and incremental additions of 0.05% (50 mg kg-1), 0.1% (100 mg kg-1), and 0.15% (150 mg kg-1) for the experimental groups U50, U100, and U150 respectively. Groups of 45 fish weighing 3.126 ± 0.120 g were fed these diets over 90 days. The study found that groups treated with UFE showed statistically significant enhancements (p < 0.05) compared to the control group. These improvements included increased red and white blood cell counts, higher haemoglobin concentrations, greater packed cell volume, and elevated enzyme activities-specifically, superoxide dismutase, catalase, alanine aminotransferase, and aspartate aminotransferase. Additionally, lysozyme and phagocytic activities were notably higher, especially in the U100 group after exposure. Before exposure to Aeromonas hydrophila, all levels of UFE supplementation led to increased expression of TNF-α and COXII genes and decreased NFκ-B expression. After the challenge, UFE intake resulted in varied expression levels of immune and antioxidant genes (TNF-α, NFκ-B, SOD, and COXII) in the liver, with the most effective responses observed in the U50, U100, and U150 groups. The findings underscore the potential of dietary UFE as a natural antioxidant and immune booster for Nile tilapia.

Curcumin’s effects on growth indices, histological scores, blood metabolites, redox state, immunity, and antioxidant-related genes of red tilapia (Oreochromis sp.)

Curcumin, a polyphenol, targets multiple signaling molecules and shows activity at the cellular level, supporting its various health benefits. Thereafter, the present study examines the effects of different doses of dietary curcumin on growth indices, feed efficiency, serum metabolites, redox (oxidation) status, immunity, histological assessment, and antioxidant-related genes in red tilapia (Oreochromis sp, Oreochromis aureus x O. mossambicus). A total of 1200 red tilapia with an average weight of 19.1±0.03 g were distributed in 12 cement ponds (3×3.5×1m). Each treatment was assigned three pounds (n=100 replicates). For 60 days, fish were fed baseline diets containing 0, 0.4, 0.6, and 0.8 g of curcumin/kg of diet. The treated fish showed increased body weight and SGR (specific growth rate) compared to the T0 group (P<0.05). Curcumin in the diet significantly improved weight gain, percentages, and FCR (feed conversion ratio), with a dose-dependent effect (P < 0.05). Curcumin supplementation showed no influence on feed intake, fish mortality, or survival rate (P >0.05). The curcumin-treated fish groups improved tissue structure in hepatocytes, pancreatic lumens, hepatic blood sinusoids, and intestine tissue layers, particularly the mucosal layer. The T0.8 group had reduced liver enzymes (AST and ALT) and greater total protein and albumin levels (P<0.05). The T0.6 and T0.8 groups showed significantly lower MDA levels than the other groups (P < 0.05). Curcumin groups demonstrated significantly higher antioxidant indices (CAT, GPx, and SOD) compared to the basal diet (P<0.05). Curcumin administration resulted in significant improvements in IgM and lysosome levels (P<0.05). All supplemented groups had considerably (P<0.05) higher levels of SOD, CAT, and GPx mRNA than the control group. Consequently, administering 0.6–0.8 g/kg of curcumin to red tilapia (Oreochromis sp.) diets may improve the fish’s growth, health, tissue composition, and antioxidant response.

Dietary lysophospholipid improves growth performance, antioxidant capacity and immunity response of red tilapia (Oreochromis niloticus × O. mossambicus)

Lysophospholipids (LPL) are usually used as emulsifiers in fish nutrition because of their ability to ameliorate nutrient digestibility and lipid metabolism. The present study aims to assess the effects of a commercial dietary lysophospholipid on growth performance, feed utilization, antioxidant activity, innate immunity and biochemical indices of red tilapia (Oreochromis niloticus x O. mosambicus) fingerlings. Five isonitrogenous (35.8% CP) and isocaloric (18.7 MJ kg−1) diets were prepared as follows: two control diets coded as C1 and C2, containing 2 and 1% soybean oil, respectively. The other three diets were coded as LPL1, LPL2 and LPL3, and were formulated by supplementing the C2 diet with 0.1, 0.2 and 0.3% lysophospholipid. The fingerlings of red tilapia (2.13 ± 0.42 g fish−1) were fed the diets for 70 days. The highest significant (p < 0.05) final weight and weight gain were recorded in LPL2. The best values of feed efficiency and protein efficiency (PER)were in all fish groups fed LPL in their diets (p < 0.05). Protein productive value (PPV) showed the highest result in LPL3 (p < 0.05). Lysozyme activity showed the best result in LPL3 (p < 0.05). The highest values of alternative complement activity (ACH50) and total immunoglobulin (Ig) were in LPL3 and LPL2 (p < 0.05). The best results of superoxide dismutase (SOD) and catalase activity were recorded in LPL3 (p < 0.05). The lowest values of triglycerides (TG) and total cholesterol (CHO) were detected in LPL1 and LPL2 (p < 0.05). Thus, the inclusion of 0.2% of the commercial lysophospholipid in red tilapia diets enhanced the growth performance, feed utilization, innate immunity, antioxidant activity and lipase activity, and reduced CHO and TG of red tilapia fingerlings.

Partial Replacement of Fishmeal with Black Soldier Fly Larvae Meal in Nile Tilapia Diets Improves Performance and Profitability in Earthen Pond

Insect meals have the potential to be used as a source of nutrients in aquafeeds due to their high nutritional profile and cost effectiveness. The objective of this study was to elucidate the impact of black soldier fly larvae meal (BSFLM) as a replacement for fish meal (FM) on Nile tilapia (Oreochromis niloticus, L) growth performance, survival rate, somatic indexes and economic benefits. Four experimental diets were prepared; three with BSFLM as a substitute for FM at 25 % (T25 %), 50 % (T50 %) and 75 % (T75 %) and a control diet without BSFLM (T0 %, 100 % FM). A total of 360 fingerlings weighing about 20 - 30 gs each were assigned to twelve cages built in a 720m2 earthen pond, with 30 fingerlings in each cage in a completely randomized design with three replications in each treatment group. The fingerlings were fed the experimental diets for 26 weeks. The results showed that the treatment diets did not significantly affect body weight gain and daily feed intake (p > 0.05). However, treatment T50 % (52.16 g) had the highest body weight gain while treatment T75 % (46.00 g) had the lowest body weight gain even though not statistically different (p > 0.05). The body length also followed the same trend being higher in T50 % (16.50 cm) and lowest in T75 % (15.91 cm). The survival rate was significantly influenced (p < 0.05) by the diet treatment groups, while blood parameters, visceral somatic and hepatosomatic indexes did not vary significantly (p > 0.05) across the treatment diets. Return on investment and the cost-benefit ratio were significantly (p < 0.05) affected by the partial replacement of FM with BSFLM. Diets T25 %, T50 % and T75 % had higher (p < 0.05) profit margins when compared with diet T0 % (control). The study found that BSFLM can replace FM in diets for Nile tilapia without compromising on the growth performance of the fish while also increasing the profitability.

Partial substitution of fish meal by biofloc meal in diets for Nile tilapia Oreochromis niloticus

The effect of a partial substitute of fish meal by biofloc meal on the growth and survival of fry Nile tilapia Oreochromis niloticus was evaluated over nine weeks. Two biofloc meals were obtained by drying them in two processes: A) sun exposure and B) convection oven. A randomized design of eight isonitrogenous (40%) and isoenergetic (17 kJ g-1) diets was used, where 5, 10, 15, and 20% of the fish meal was substituted for the two biofloc meals. The nutritional study was conducted in a recirculating aquaculture system with Nile tilapia fry (initial weight: 0.64 ± 0.16 g). The survival range was similar in all treatments and higher than 97%. Tilapia fed with the treatments A5, A10, B5, and B10 of substitution of biofloc meal showed similar and significantly better final weight, individual weight gain, specific growth rate, and condition factor than A15, A20, B15, and B20 treatments; as well as efficiency of use of the feed: protein efficiency ratio, carcass nitrogen deposition, apparent nitrogen utilization, and apparent digestibility. Therefore, these results suggest that biofloc meal is possible in diets for tilapia, thus reducing the need for fishmeal as the main source of protein in the diet.

Use of black soldier fly larvae and freshwater shrimp to partly substitute commercial diet for Nile tilapia cultured in smallholder fish farms – A case study in Busia County, Kenya

Fish-farming in Kenya is challenged by the availability and high cost of feed ingredients, especially protein sources. Using black soldier fly larvae (Hermetia illucens) (BSFL) directly or indirectly as a feed ingredient to feed fish is interesting as they efficiently convert organic wastes into high-quality proteins. In addition, the freshwater shrimp (Caridina nilotica) (CN), an important by-catch of the silver cyprinid (Rastrineobola argentea) fisheries in Lake Victoria, could be another alternative protein source. Therefore, this study determined whether dried BSFL or dried CN could partly substitute the commercial diet when growing Nile tilapia (Oreochromis niloticus) in a smallholder farm aggregated in an aquapark. The nutritional values and cost-effectiveness of the alternative feeding strategies were compared to commercial diet (CD) only. During an 84-day experimental period, Nile tilapia were fed one of the three feeding strategies, including the use of only the commercial diet, to be compared with diets replacing 20% of the commercial diet with BSFL or CN. The fish were fed to apparent satiation twice a day. At the end of the trial, biomass, the number of fish, growth, survival rate, total fish production, economic feed conversion rate and productivity per pond, were determined. As such, Body Weight (BW) was similar across feeding strategies (P &amp;gt; 0.05), measured 63.2 ± 3.9, 68.0 ± 7.4 and 68.0 ± 7.4 g for fish-fed diets with CD, BSFL and CN, respectively. Hence, nutritionally and from a production point of view, the three feeding strategies used in this study performed equally well. Notably, the use of BSFL led to a significantly higher economic return (P &amp;lt; 0.05) compared to the use of CN and commercial diet alone. The trials in this study demonstrate that BSFL and CN can be used to partly substitute commercial diet. In addition, the trial show that the use of BSFL to partly substitute the commercial diet can boost sustainable fish production in a smallholder farm set-up aggregated in an aquapark.

Prebiotic, probiotic and marine algae suplementation in juvenile tilapia diet

This study evaluated the probiotic mannan oligosaccharide (MOS), and marine algae for Nile tilapia (Oreochromis niloticus) feeding. The parameters analyzed were fish-growth rate, hematological and immunological parameters, and intestinal microbiota. Also, fish were submitted to experimental infection challenge with Aeromonas hydrophila to evaluate the immune response. Nile tilapia juveniles (weight 8.86 ± 3.22 g) were used in the six treatments with four replicates, for 63 days. The treatments were: control basal diet; PAS-TR: basal diet plus 0.04 g·kg-1 of the probiotic (Bacillus cereus and Bacillus subtilis); MOS: basal diet plus 4 g·kg-1 of the prebiotic mannooligosaccharide, 4 g·kg-1 of the prebiotic Kappaphycus alvarezii. Two more diets were formulated by a combination of PAS-TR + MOS (4 +4 g·kg-1), and PAS-TR + KAP (4 +4 g·kg-1). For the challenge experiment, the fish were fed for 21 days, infected via intraperitoneal injection with A. hydrophila (1 x 106 UFC·mL-1), and the mortality rate was registered for 15 days post-infection. Results indicated the capacity of probiotic to remain in the gut for 63 days, and it was inhibited neither by autochthonous microbiota nor by prebiotics used. The feed additives tested for Nile tilapia did not cause a beneficial or adverse effect on growth or hematological variables. However, these treatments protected the fish from A. hydrophyla infection, proved by higher survival rate, and relative protection levels. We concluded that probiotic PAS-TR and prebiotics MOS and KAP, combined or not as symbiotics, may promote immune protection and reduce the mortality rate of A. hydrophyla infection.

Type of black soldier fly (Hermetia illucens) larvae frass influences the nutritional value when included in a prepared diet for Mozambique tilapia (Oreochromis mossambicus)

Black soldier fly (Hermetia illucens) larvae (BSFL) farming is expected to increase, and a by-product is the ‘frass’. The dietary inclusion of BSFL frass has been shown to enhance tilapia and catfish growth/immunity. However, the composition of BSFL frass, and potentially their nutritive value to fish, may depend on the initial provided substrate. In this 8-week nutrition trial, BSFL frass made from either expired fish diet (EFD; 45% crude protein) or a combination of fruits/vegetable peels (FV; 9.3% crude protein) were included in the diets of Mozambique tilapia (Oreochromis mozambicus) at 5% or 10%. The EFD and FV frass had a different nitrogen, mineral, and amino acid profile, and this information was used to formulate the diets. Results showed that EFD frass at 10% significantly (P < 0.05) enhanced tilapia growth compared to fish fed the control diet, but performance of fish fed the other test diets were not different (P > 0.05) from the control. There was no significant difference in the crude protein or lipid content of tilapia, but some differences were observed in the amino acid and fatty acid composition. Among the test minerals, only phosphorus was significantly affected, which was higher in tilapia fed the FV frass diets. Liver histology showed some minor inflammation and blood vessel congestion in tilapia fed the 10% frass diets, while the intestinal histology had a better cumulative score among all the frass diets compared to the control. Results indicate that the initial substrate provided to the BSFL can influence the nutritive value of the frass to fish.

Feasibility of molasses-fermented banana peel as a protein source in practical diet for hybrid tilapia (Oreochromis spp.): effect on growth and feed efficiency

This study aims to increase the utilization of banana peels, a local agricultural by-product, by improving nutrient value and partially reducing the presence of anti-nutritional factors (ANFs) as an alternative ingredient in fish feed. The feasibility of molasses-fermented banana peels (MFBP) as a protein source in a practical diet for hybrid tilapia (Oreochromis spp.) fries was investigated. Five isonitrogenous experimental diets containing 0 (control), 25, 50, 75, and 100% substitution levels of fish meal by MFBP were formulated. Twenty tilapia fries per group with three replicates were fed for eight weeks. The growth performance and feed efficiency values of fish were recorded and evaluated. Fish fed with 0, 25, and 50% MFBP levels showed significantly higher growth parameters, survival rate, and feed utilization efficiency than those fed with 75 and 100% MFBP levels. Although the control diet produced better growth performance and feed utilization efficiency than MFBP-based diets there was no significant difference between fish fed with the control diet and the low MFBP levels (0-50%) diet. Based on the present findings, it could be concluded that the molasses-fermented banana peels (MFBP) could efficiently replace the fishmeal by up to 50% without affecting the growth performance of red tilapia.

Effects of supplementation with different zinc-based products on the growth and health of Nile tilapia

Zinc is one of the essential microelements for the metabolism of animals. Zinc nanoparticles may have higher bioavailability due to their low specific surface area, facilitating absorption by fish. The present study aimed to evaluate the effects of supplementation with different zinc-based products on the growth and health of Nile tilapia Oreochromis niloticus. Zinc, in different sizes (nanoparticles or bulk) and forms (inorganic or organic), were used as a supplement in the tilapia diet at a dose of 15 mg kg feed−1 for 60 days. At the end of the feeding trial, production performance, hemato-immunological parameters, activity of antioxidant system enzymes, exposure to Streptococcus agalactiae and zinc concentration in the muscle were examined. After the bacterial challenge, the mean corpuscular hemoglobin concentration (MCHC) significantly increased in the fish treated with organic zinc, inorganic nano zinc, and organic nano zinc, while in the control group (inorganic zinc), MCHC remained unchanged. Regarding defense cells, dietary inorganic nano zinc increased the number of basophils (1.50 ± 1.10) compared to organic zinc (0.80 ± 0.90). Lymphocyte count increased after the challenge only in the organic zinc treatments (bulk and nanoparticles). Neutrophils decreased in the control (inorganic zinc) (2.20 ± 1.70) and inorganic nano zinc (2.60 ± 2.70) treatments after the challenge. When compared before and after the bacterial challenge, the plasma antimicrobial titer significantly increased after the bacterial challenge in all treatments. No significant differences were observed for total proteins, enzymes (SOD and CAT), cumulative survival and zinc deposition on fillet. In conclusion, organic zinc in nanoparticles or bulk size increased Nile tilapia innate defense during bacterial infection. However, the other parameters evaluated were not affected by zinc particle size or form (organic or inorganic), indicating that further evaluations should be conducted with organic zinc in nanoparticles or bulk size in the tilapia diet.

Water quality change, growth performance, health status in response to dietary inclusion of black soldier fly larvae meal in the diet of Nile tilapia, Oreochromis niloticus

Abstract With increasing intensive aquaculture production, the search for nourishing, environmentally, and economically viable fishmeal (FM) alternative is an endless approach. Therefore, the present study examines the effect of the use of black soldier fly, Hermetia illucens, larvae meal (BSFM) as an alternative protein for FM in the diet of Nile tilapia, Oreochromis niloticus, on nitrogen wastes, zootechnical performance, body composition, and hematobiochemical parameters. A total of 315 Nile tilapia fingerlings (4.11±0.12 g/fish) were divided into seven treatments in triplicate. The fish were stocked in glass aquaria (50 × 40 × 30 cm; 60 L each) at a rate of 15 fish per aquarium. Experimental diets contained BSFM at increasing levels of 0, 5, 10, 15, 20, 25, and 30% as FM replacers were offered twice daily to apparent satiation for 84 days. The results revealed that BSFM replacements significantly (P = 0.001) enhance water quality and reduce the total ammonia, NH3, and NO2 levels compared to the control. The growth performance, feed conversion ratio, and survival were improved with increasing BSFM meal inclusion levels up to 25% (P = 0.001, 0.017, and 0.001, respectively). However, the zootechnical performance of the experimental fish started to decline with increasing replacement levels to 30%. Also, by an increase in BSFM level to 25%, hematobiochemical markers were considerably (P≤0.01) enhanced. The liver and kidney function indicators improved (P = 0.001) with dietary BSFM. The economic evaluation revealed that feed costs and fish weight gain were decreased by increasing BSFM levels in fish diets. The current study highlighted the potential environmentally beneficial use of BSFM as an FM replacer in terms of reducing water nitrogen waste levels and improving growth performance, health status, and enhancing the economic feasibility of the commercial tilapia diet.

Dietary garden cress (Lepidium sativum) seeds mitigate the effect of aflatoxin B1 contamination on growth, antioxidant status, AFB1 residues, immune response, and tissue architecture of Oreochromis niloticus

The contamination of fish diets with aflatoxin B1 (AFB1) poses a significant hazard to the aquaculture sector. This study investigates the efficacy of supplementing Nile tilapia (Oreochromis niloticus) diets with garden cress (Lepidium sativum) seeds (GCS) to mitigate the adverse effects of AFB1. For this purpose, a factorial design was utilized, consisting of a 2×3 arrangement of treatments. This included two contamination levels of AFB1: (0 and 2 mg kg−1 diet). Within each contamination level, three dietary levels of GCS were used (0 %, 1 %, and 2 %). The study involved 270 healthy O. niloticus with an average weight of 25.14 ± 0.39 g (45 fish/group and 15 fish/replicate). The duration of the trial was 60 days. The study evaluated growth performance, hematological indices, hepatorenal function, immune and antioxidant indicators, histomorphology of organs, AFB1 residues in muscles, and fish resistance to Aeromonas hydrophila. The results indicated that GCS dietary supplementation significantly counteracted AFB1-induced growth retardation and reduced fish survival. Additionally, GCS effectively reversed the anemia, leukopenia, hypoproteinemia, hypoalbuminemia, and hypoglobulinemia that were produced by AFB1. Moreover, GCS dietary supplementation significantly suppressed the AFB1-induced increase in serum bilirubin, hepatic enzymes, kidney damage products, cortisol, and glucose. Additionally, the inclusion of GCS in the fish's diet effectively eliminated the accumulation of AFB1 in their muscles. Moreover, GCS supplementation demonstrated significant restoration of depleted antioxidant and innate immune components induced by AFB1. Furthermore, GCS significantly reduced the degenerative changes in renal, hepatic, splenic, and small intestine tissues caused by AFB1. Fish fed a GCS-fortified diet and exposed to AFB1 displayed restored disease resistance when challenged with A. hydrophila. In conclusion, supplementing Nile tilapia diets with GCS at 2 %, even in the presence the AFB1 contamination, significantly enhanced the fish growth, improved health, and increased disease resistance while reducing AFB1 residues, thereby benefiting consumer health.

Impacts of astaxanthin-enriched Paracoccus carotinifaciens on growth, immune responses, and reproduction performance of broodstock Nile tilapia during winter season.

The growth, immune response, and reproductive performance of broodstock of Nile tilapia (Oreochromis niloticus) under winter stress conditions were investigated the effects of supplementary diets with astaxanthin-enriched Paracoccus carotinifaciens. Throughout an eight-week period in the winter season, male and female tilapia were fed with diets containing different levels of P. carotinifaciens dietary supplementation: 0 g/kg (T1; control), 5 g/kg (T2), 10 g/kg (T3), and 20 g/kg (T4). Subsequently, a four-week mating system was implemented during the winter stress period. The results revealed that there were no significant differences observed in growth, hematological indices, and blood chemical profiles among all treatment groups for both male and female tilapia. However, a significant increase in cholesterol content was noted in both male and female tilapia fed with the T4 diet (p<0.05). The total carotenoid content in the muscle was evaluated, and significantly higher values were found in both male and female tilapia that fed T4 supplementation (p<0.05). Moreover, immunological parameters such as myeloperoxidase and antioxidant parameters in the liver including superoxide dismutase activity and catalase enzyme activity showed significant increases in tilapia fed with the T4 diet. The impact of P. carotinifaciens supplementation on broodstock tilapia indicated a significant increase in spermatozoa concentration in males and increased egg production in females after consumption of the T4 diet (p<0.05). Thus, this study highlighted that the presence of astaxanthin-enriched P. carotinifaciens in the diet of broodstock Nile tilapia can lead to the accumulation of carotenoids in their muscle tissue, improvement in antioxidant status, enhancement of immune function, and potential enhancement of reproductive capabilities, even under overwintering conditions.

Dietary microalgal-fabricated selenium nanoparticles improve Nile tilapia biochemical indices, immune-related gene expression, and intestinal immunity

BackgroundFeed supplements, including essential trace elements are believed to play an important role in augmenting fish immune response. In this context, selenium nanoparticles (SeNPs) in fish diets via a green biosynthesis strategy have attracted considerable interest. In this investigation, selenium nanoparticles (SeNPs, 79.26 nm) synthesized from the green microalga Pediastrum boryanum were incorporated into Nile tilapia diets to explore its beneficial effects on the immune defense and intestinal integrity, in comparison with control basal diets containing inorganic Se source. Nile tilapia (No. 180, 54–57 g) were fed on three formulated diets at concentrations of 0, 0.75, and 1.5 mg/kg of SeNPs for 8 weeks. After the trial completion, tissue bioaccumulation, biochemical indices, antioxidant and pro-inflammatory cytokine-related genes, and intestinal histological examination were analyzed.ResultsOur finding revealed that dietary SeNPs significantly decreased (P < 0.05) serum alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and cholesterol, while increasing (P < 0.05) high-density lipoproteins (HDL). The Se concentration in the muscle tissues showed a dose-dependent increase. SeNPs at a dose of 1.5 mg/kg significantly upregulated intestinal interleukin 8 (IL-8) and interleukin 1 beta (IL-1β) gene transcription compared with the control diet. Glutathione reductase (GSR) and glutathione synthetase (GSS) genes were significantly upregulated in both SeNPs-supplemented groups compared with the control. No apoptotic changes or cell damages were observed as indicated by proliferating cell nuclear antigen (PCNA) and caspase-3 gene expression and evidenced histopathologically. SeNPs supplementation positively affects mucin-producing goblet cells (GCs), particularly at dose of 1.5 mg/kg.ConclusionTherefore, these results suggest that Green synthesized SeNPs supplementation has promising effects on enhancing Nile tilapia immunity and maintaining their intestinal health.