Growth Of Tilapia Research Articles

Temperature and feeding frequency: interactions with growth, immune response, and water quality in juvenile Nile tilapia

Abstract Background Water temperature and feeding frequency are critical abiotic factors regulating the growth and immune function of aquatic organisms. This study investigated the effects of water temperature and feeding frequency on growth and immune function in Nile tilapia (Oreochromis niloticus) over two months. A total of 360 juvenile fish (average weight: 20.00 ± 1.26 g) were divided into six groups, each with three replicates, based on a combination of three water temperatures (26, 28, and 30 °C) and two feeding frequencies (either 1 or 2 meals per day). Results At 30 ºC and 28 ºC, water electrical conductivity and total dissolved salts increased, while total ammonia nitrogen and dissolved oxygen rose slightly in groups fed twice daily, with a significant interaction between temperature and feeding frequency. The group at 30 ºC with two meals per day showed the highest final body weight (FBW). The interaction between temperature and feeding frequency significantly influenced FBW, total feed intake, and body thickness. Fish at 30 ºC exhibited upregulated hepatic growth hormone receptor 1 and insulin-like growth factor 1, while those at 28 ºC with one meal per day, as well as those at 30 ºC regardless of meal frequency, also showed increased expression of hepatic fatty acid binding protein and intestinal cluster of differentiation 36. Fish at 30 ºC had upregulated leptin levels and downregulated cholecystokinin, while those at 26 ºC displayed the opposite trend, particularly with one meal daily. Higher temperatures significantly boosted serum IgM, superoxide dismutase (SOD), and lysozyme (LYZ) levels, with meal frequency also affecting malondialdehyde, IgM, and SOD levels. Additionally, 30 ºC enhanced the hepatic expression of mucin-like protein (muc), oligo-peptide transporter 1 (pept1), interleukin 1, nf-κB, complement C3, lyz, sod, catalase, and glutathione peroxidase, with twice-daily meals having a more pronounced effect. Conversely, 28 ºC with one meal per day upregulated some of these genes, such as muc, pept1, and sod. Conclusions Overall, 30 ºC with two meals per day significantly improved the growth and health of juvenile Nile tilapia, while 28 ºC with two meals maintained satisfactory performance.

Phytochemical Screening of Seaweed Flour (Eucheuma cottonii) Using Various Organic Solvents and Its Application in Tilapia Feed (Oreochromis niloticus)

This study aims to qualitatively analyze the bioactive compounds in Eucheuma cottonii seaweed flour extract and its application in commercial feed for tilapia (Oreochromis niloticus). The methodology employed is experimental and consists of two phases. Phase 1 involves the extraction of E. cottonii flour using three different organic solvents with varying polarity (ethanol, ethyl acetate, and a combination of ethanol + ethyl acetate). The testing parameters include qualitative phytochemical tests for alkaloids, steroids/triterpenoids, saponins, flavonoids, and tannins. Phase 2 consists of the application of the extract to tilapia over a 30-day rearing period with four treatments: control/commercial feed (P0), commercial feed + ethanol extract (P1), commercial feed + ethyl acetate extract (P2), and commercial feed + combined ethanol and ethyl acetate extract (P3). The parameters tested include absolute weight, specific growth rate, survival rate, and water quality. Phytochemical and water quality data are presented in table format. Meanwhile, growth and survival data are analyzed using ANOVA, followed by Duncan’s test for significant differences. The results of the researches carried out, it can be concluded that the phytochemical analysis of E. cottonii extract in ethanol and the ethanol + ethyl acetate combination yielded similar compounds: alkaloids, steroids/triterpenoids, and flavonoids. The ethyl acetate extract contained triterpenoids and flavonoids. Both saponins and tannins returned negative results across all organic solvent treatments. All treatments with the addition of E. cottonii seaweed extract in various organic solvents demonstrated better growth in tilapia compared to the control treatment.

Dietary vitamin E (α-tocopherol acetate) modulates growth, digestive enzymes, histopathology, and vulnerability of Nile tilapia, Oreochromis niloticus to Aeromonas hydrophila infection

Vitamin E is a fat-soluble vitamin that plays a vital function in several biological processes, and fish cannot synthesize it to meet their requirement. So, 56-day research was conducted to examine the influence of vitamin E (vit-E) (α-tocopherol acetate) on the Nile tilapia's growth, digestive enzymes, hematology, histology, and susceptibility to Aeromonas hydrophila. A total of 450 mono-sex Acclimated Nile tilapia (Oreochromis niloticus) were haphazardly dispersed into 30 aquaria, each with a capacity of 100 liters (15 fish/aquarium) to exemplify five groups with six replicates. A control diet (30 % protein) was enriched with 0.0 (E0), 150 (E150), 300 (E300), 600 (E600), and 1200 (E1200) mg/kg feed. Fish (13.5 ± 0.12 g) were given the trial diets until obvious satiation thrice daily for 56 days. At the end of the feeding trial, growth performance, digestive enzymes, hematology, and histology for the mid-intestine were examined. Subsequently, twenty fish from each treatment were challenged to contagion with Aeromonas hydrophila bacteria, and fish mortality was recorded for a further 14 days. At the end of the bacterial challenge, histology for the mid-intestine, liver, and spleen tissues was examined. Growth performance, feed utilization, and digestive enzyme secretion (proteases, lipase, and α-amylase) were substantially (P < 0.5) improved with raising vit-E levels in fish feeds up to E1200. Increasing the vit-E doses improved fish gut histomorphology by increasing the count and size of intestinal folds bordered by well-arranged enterocytes. The body composition was not influenced by dietary vitamin E, except lipid content, which increased substantially as vitamin E levels increased. Fish fed with vita-E enriched diets had higher resistance to A. hydrophila infection; however, the control group exhibited the greatest fish mortality rate (80 %), while the lowest rate was observed at E1200 (30 %). Hepatic and spleen tissues in the control group (E0) showed severe congestion and degeneration, whereas vit-E-treated fish groups progressively recovered normal histomorphology depending on the vit-E doses. Finally, this research recommends feeding Nile tilapia on vit-E, particularly 1200 mg/kg feed, to enhance its performance, welfare status, and resistance to A. hydrophila contagion.

Evaluating Black Soldier Fly and Bloodworm Larvae Meals as Sustainable Protein Sources for Growth and Survival of Red Hybrid Tilapia (Oreochromis spp.) in the Nursery Phase

Aims: This study aimed to assess the effects of using insect larvae meals, such as BSF and BW larvae, as alternative feeds to commercial pellets on the growth performance and survival of Oreochromis spp. at the nursery stage. Study Design: This study followed the randomized control treatment with three different diet. Place and Duration of Study: This study was carried out at the Fisheries Research Institute Glami Lemi (FRIGL) in Negeri Sembilan, Malaysia, within 35 days from July to August 2023. Methodology: A total of 360 red hybrid tilapia (Oreochromis spp.) fingerlings weighing 0.62 ± 0.06 g were randomly distributed into 12 rectangular aquarium tanks (250mm) at a stocking density of 30 fish per tank. They were fed with commercial pellets (CP), Black Soldier Fly (BSF) larvae, and Bloodworm (BW). The feed amount was calculated at 10% of the total body weight per tank, with feeding conducted three times daily. The experimental setup was performed in triplicate. For the analysis of growth performances and fish survival, sampling was conducted weekly. Results: BSF larvae meal had high lipid and protein content, measuring 35.35 ± 0.21% and 29.67 ± 0.98%, respectively. BW larvae meal also showed high lipid and protein content, with 28.23 ± 1.33% and 27.94 ± 0.52%, respectively. Fish fed with BSF and BW larvae exhibited significantly higher survival rates, 93.3 ± 3.3% and 86.7 ± 14.5%, respectively, compared to the control group. Meanwhile, the group fed with the commercial pellet showed the lowest survival rate, just 74.4 ± 12.6%. Fish fed with the BW larvae recorded the highest weight gain, 1.07 ± 0.16 g, followed by fish fed with BSF larvae, 0.66 ± 0.11 g, and then fish fed with commercial pellets, 0.41 ± 0.09 g. Conclusion: Both BSF and BW larvae exhibited significant growth response properties to tilapia fingerings compared to commercial pellets. The findings from this study are promising and should be further verified at the farm scale.

Dietary Administration Effects of Microbial Exopolysaccharide from Bacillus subtilis P1 on Growth Performance and Immunity in Nile Tilapia (Oreochromis niloticus)

Exopolysaccharide (EPS)-producing bacteria were isolated from the intestines of freshwater fish as prebiotics. Among the isolates, Bacillus sp. P1 was the potent EPS producer, with a high EPS production, and was then identified as Bacillus subtilis P1 based on 16S rRNA and biochemical characteristics. The produced microbial EPS was characterized by its functional groups by FTIR, showing a 90.20% correlation to inulin, while the EPS molecular weight was approximately 105 Da with a high PDI (&gt;1.5). Moreover, the EPS from B. subtilis P1 was assessed for prebiotic properties by growing probiotic bacteria, and significant cell growth occurred in sugar-free TSB with 0.5% EPS (p &lt; 0.05). EPS exhibited approximately 55.37% DPPH radical scavenging at 20 mg/mL and inhibited certain fish pathogens at 400 μg/mL (10–13 mm inhibition zone). Low EPS cytotoxicity was confirmed (&lt;1% hemolysis) prior to use as immunobiotics in Nile Tilapia (Oreochromis niloticus) diet supplementation. Nile tilapia growth and immune response were monitored after feeding with control (C), basal diet (BD), and treatment (T): BD + EPS 5 g/kg. In the T-group, the weight gain (WG), % specific growth rate (SGR), and average daily gain (ADG) significantly increased compared to the control (p &lt; 0.05) by week 4, with no negative effects on blood chemistry parameters. Lysozyme activity and respiratory burst activity in T-groups were significantly higher than the control (p &lt; 0.05), with a 50% RLP survival rate of Nile Tilapia infected by Aeromonas veronii in the T-group after a two-week challenge. On the other hand, the proximate analysis revealed higher protein content in the T-group. These findings suggest that EPS from B. subtilis P1 in fish diets efficiently supports fish growth and stimulates innate immune response in Nile Tilapia, thus showing potential as the immunobiotics for aquaculture.

Proximate Analysis On Nile Tilapia Artificial Feed From Shrimp Waste

Nile Tilapia (Oreochromis niloticus) is the most widely cultivated freshwater fish because it can grow well in tropical countries and temperate regions. This research aims to create artificial feed that matches the nutritional parameters needed by nile tilapia. This artificial feed will use the basic ingredients of shrimp waste, with addition of oilcake, bran, starch flour, vitamins, squid oil, and water. There are four variables used to make artificial feed with different basic and additional ingredients, as well as varied processing techniques. After artificial feed is completed, proximate analysis will be carried out to test composition of crude fiber, carbohydrates, water, fat, ash, and protein using various methods. The test method for the composition of crude fiber, carbohydrates, fat, ash, and protein follows the method set by the Association of Official Analytical Chemists (AOAC). Based on the results of proximate analysis, variable 1 (V1) has fulfilled the nutritional content of protein and moisture content needed by nile tilapia. This shows that artificial feed formulations from shrimp waste can be used because protein is an important element for nile tilapia growth, but the content of crude fiber, carbohydrates, fat, and ash exceeds ideal value for nile tilapia nutrition. This also occurs in variables 2, 3, and 4 that have not met nutritional needs, especially protein. However, the composition of artificial feed with shrimp waste and addition of meal, bran, starch flour, vitamins, and water in V1 can be further investigated to reduce the content of crude fiber, carbohydrates, fat, and ash.

Enhancing growth, immunity, and gene expression in Nile Tilapia (Oreochromis niloticus) through dietary supplementation with avocado (Persea americana) seed powder

This study evaluated the effects of dietary supplementation with different doses (0, 10, 20, 40, and 80 g kg−1) of powdered avocado seed (AS) on the growth performance, immunological response, and gene expression of Nile tilapia (Oreochromis niloticus) reared in a biofloc system over 8 weeks. A total of 300 Nile tilapia fingerlings (average weight 14.67 ± 0.07 g) were randomly assigned to five treatment groups, each with three replicates, and 20 fish per tank. The results demonstrated significant improvements (p < 0.05) in growth and immune response in AS-supplemented fish, particularly in those fed the 10 g kg−1 AS diet (AS10), which showed the most notable increases. In contrast, fish fed higher AS doses (AS20, AS40, and AS80) exhibited no statistically significant differences compared to the control group (p > 0.05). Additionally, the AS10 group exhibited a significant upregulation (p < 0.05) in the mRNA expression of key immune-related genes (IL-1, IL-8, and LBP) and antioxidant-related genes (GST-α, GPX, and GSR) in both liver and intestinal tissues, indicating enhanced immune and antioxidant responses. The highest expression levels were found in the AS10 group. These findings suggest that the inclusion of 10 g kg−1 powdered avocado seed in the diet substantially enhances growth, immune function, and gene expression in Nile tilapia reared in a biofloc system. The results highlight avocado seed as a promising feed additive for improving the sustainability of Nile tilapia aquaculture.

Evaluation of storage stability of poultry by-product meal incorporated fish feed under aerobic storage condition

The research focused on development of fish feed utilising poultry by-product meal (PBM) as a substitute for fish meal (FM) and evaluating its shelf life under aerobic packaging conditions. Initially, a basal diet (C) was formulated to meet the nutritional requirements for optimal growth of Tilapia by using FM as the major protein source. After analysing the nutritional composition of PBM, an isoproteinaceous diet (T) was formulated by replacing FM with PBM. The product was packed in HDPE bags and kept at room temperature and analysed for physico chemical and microbial characteristics for 45 days at weekly intervals. Moisture content of both C and T decreased significantly (p0.05) was found between C and T. The TBARS value of both C and T followed an increasing trend. This increase in C was not significant (p&lt;0.01) between 28th and 35th day, and between 42nd and 45th day but that of T increased significantly (p&lt;0.01) throughout the storage period. T consistently displayed the highest TBARS value during storage period. Tyrosine Value (TV) of both C and T also increased during storage and was significant (p&lt;0.01) up to 42nd day of storage. C exhibited the highest TV throughout the storage period. Similarly, total viable count (TVC) of both C and T increased on storage. The increase in TVC for C was not significant (p&lt;0.01) between 21st and 28th days, whereas that of T was significant (p&lt;0.01) throughout the storage period. On 45th day, T exhibited highest count and was significantly different (p&lt;0.01) from C. Throughout the 45-day storage period, no observable coliform count or yeast and mould count was noted in either C or T. The present study indicated that fish feed can be effectively prepared by utilising PBM and can be stored under room temperature up to 45 days. Keywords: Poultry by-product meal, fish meal, fish feed, storage stability

Differences in Growth Performance and Meat Quality between Male and Female Juvenile Nile Tilapia (Oreochromis niloticus) during Separate Rearing.

This study compared the growth and flesh quality of juvenile male and female Nile tilapia grown in separate RAS tanks. The Genetic Sex Determination method yielded 40 males and 40 females. Males grew longer and heavier than females, and the results showed significant variation between the sexes in terms of weight gain rate (WGR), specific growth rate (SGR), and final body length and weight. In terms of the feed conversion ratio (FCR), Gonad Somatic Index (GSI), and Viscera Somatic Index (VSI), females presented better results than males. Male and female Hepatosomatic Index (HSI) values did not differ significantly-no difference in blood serum values. The meat's moisture and crude protein composition did not alter significantly from male to female; however, the crude fat and ash levels did differ significantly. Male and female animals were given the same seventeen distinct types of amino acids, and there was no distinct variation in the profiles of total amino acids (TAAs) and essential amino acids (EAAs) between the sexes. However, in the non-essential amino acid (NEAA) category, there were marginally significant differences, wherein females performed better than males. Males and females differed considerably in crude fat and ash levels but not in the moisture content or crude protein composition of the meat. Regarding fatty acids, males outperformed females in terms of total fatty acids (TFAs), polyunsaturated fatty acids (PUFAs), and saturated fatty acids (SFAs). However, no significant difference in the amount of monounsaturated fatty acids (MUFAs) in muscle was found between males and females.

Investigation of the effect of water and feed sourced boron on the growth performance and blood parameters of Nile tilapia, Oreochromis niloticus

AbstractThis study investigated the effects of water and feed‐derived boron on the growth performance and blood parameters of Nile tilapia fingerlings. Two different experiments were designed for this purpose. The first phase of the study determined the LC50 (96‐h) value of boron for Nile tilapia. Fish were then fed in water containing boron at a ratio of 1:20 of the LC50 value. In the second experiment, feed containing boron at different rates (0.00%, 0.01%, 0.05%, and 0.10%) was fed for 40 days. At the end of the feeding period, growth performance, hematology, and blood biochemistry parameters were determined. The study concluded with a calculated LC50 value of 161.053 mg/L boron for Nile tilapia. The initial weight was 12.51 ± 0.79 g; at the end of feeding, the final weights were determined as 26.36 ± 0.15 g for the control and 28.07 ± 0.23, 32.28 ± 0.25 and 24.81 ± 0.48 g for 0.01%, 0.05% and 0.10% of boron feed treatments, respectively. At the end of feeding in water containing boron, the final weight of Nile tilapia was determined as 24.26 ± 0.26 g (LC50/20%). The results showed that feeding Nile tilapia with 0.05% boron‐supplemented feed stimulated growth and positively affected blood parameters, whereas waterborne boron inhibited Nile tilapia growth and negatively affected blood parameters.

The effect of different levels of L-isoleucine in compound feeds on the growth of tilapia (Oreochromis niloticus)

Four diets were developed, including the control (main diet), which actually contained 34.00% crude protein, while the other three contained protein close to this value, taking into account the measurement error, and isoleucine in groups 2, 3 and 4, 4.9%, 8.51% and 12.12%, respectively. The study of the effect of L-isoleucine additives in compound feeds on the growth of tilapia (Oreochromis niloticus) showed that varying the concentration of this amino acid has a significant effect on fish growth rates. Adjusting dosages makes it possible to achieve more efficient use of feed in aquaculture conditions. It was found that when the amino acid isoleucine is introduced into the diet, feed conversion decreases by 0.64 points with an additional concentration of 1.42 g/kg of feed (4.9%), by 0.88 points with additional administration of isoleucine by 1.55 g/kg of feed (8.51%), by 0.76 points with an additional concentration of 1.68 g/kg of feed (12.12%). It was shown that the best group with the lowest feed conversion rate was the 3rd group, in which the amino acid isoleucine was introduced into the diet by 8.51% more than in other groups. The optimal level of isoleucine administration in tilapia feed is 1.55 g/kg of feed (8.51%). It was found that the ash content in the carcass of O. niloticus increased by 0.8%, fat — by 1% in muscles compared with the control.

Growth, biochemical indexes, and intestinal microbiota response of red tilapia (Oreochromis spp.) under different densities and feeding frequencies in the land-based aquaculture tank

Red tilapia (Oreochromis spp.) has been favored by farmers in recent years because of its superior growth performance and competitive market price, but there is a lack of experimental data related to growth and health of red tilapia in land-based aquaculture tanks. In this study, red tilapia (initial weight 27.62 ± 2.43 g) was cultured with three stocking densities (30, 40, or 50 fish/m3, named 30F,40F and 50F) in the culture mode for 60 days, including two feeding frequencies (2 or 3 times/day, named 2 T and 3 T), and various growth and metabolic parameters were assessed along with the intestinal microbiome analysis. The 30 fish/m3 groups achieved the better weigh gain rate and specific growth rate (p < 0.05). The growth rate and condition factor of 40F groups were close to those of 30F groups, the yield of 40F groups were not significantly different from that of 50F groups (p > 0.05), and it had the highest survival rate (p < 0.05). The 3 T groups has a higher growth rate and yield but also has a higher rate of feed conversion (p < 0.05). The 30F groups had higher lipase levels, but a higher fat content in this group, more lipids were observed in the liver, and resulted in higher blood glucose levels (p < 0.05). The 40F groups showed healthier physiological and biochemical indicators, as its total cholesterol, lysozyme and antioxidant enzymes levels were similar to those of the 30F groups (p > 0.05), alkaline phosphatase, amylase and trypsin levels were higher than those of the other groups, and aspartate transaminase levels were the lowest (p < 0.05). The 50F groups had higher cortisol, alanine transaminase and malondialdehyde levels, lower lysozyme and digestive enzyme activities, and blood cell infiltration in the liver (p < 0.05). In terms of different feeding frequencies, the 3 T groups had higher crude protein content, catalase and total superoxide dismutase levels, wider villus width and lower blood glucose level, while the 2 T groups had higher triglyceride, total cholesterol, lysozyme, alkaline phosphatase and some digestive enzymes activities (p < 0.05). From the perspective of intestinal microbiota. The 40F groups had a better intestinal flora, and 40F-3T groups observed a better balance of flora, while 40F-2T groups had more digestion-related flora. Considering the growth rate, health status, and yield, the optimum culture condition was determined to be stocking density of 40 fish/m3, and feedings 3 times/day were recommended. The experiment provided theoretical basis and experimental data for red tilapia culture in land-based aquaculture tank mode.

Growth and physiological responses of Nile tilapia, Oreochromis niloticus fed dietary fermented sugar beet bagasse and reared in biofloc system

Sugar beet bagasse (SB) is a common agro-industrial waste used in animal feeds. However, its high crude fiber content makes it difficult for fish to digest. Fermentation processes can improve the nutritional value of SB by-products. The study uses Lactobacillus rhamnosus and yeast (Saccharomyces cerevisiae) to ferment SB waste for use as a soybean meal substitute in Nile tilapia fingerlings. This led to an increase in protein, lipid, ash, and nitrogen-free extracts, while the fiber content decreased. Four experimental isonitrogenous (crude protein: 249.2 g kg−1) and isocaloric (gross energy:18.25 MJ kg−1) diets were formulated as follows: a control diet with 0 % LYFSB (L. rhamnosus and yeast fermented SB), and three other diets with LYFSB replacing soybean meal (SBM) at levels of 10 % (LYFSB10 %), 20 % (LYFSB20 %), and 30 % (LYFSB30 %) based on protein content, over a 70-day period. 180 fingerlings of Nile tilapia (average initial weight of 5.19 ± 0.02 g) were placed at random in twelve circular plastic tanks (60 L capacity) with a stocking density of fifteen fish each. Nitrite and ammonia levels decreased as the replacement levels of LYFSB in tilapia diets increased, while nitrate levels showed the opposite trend. The phytoplankton community includes nine species in the biofloc system and four in tilapia gut content, with Chlorophyceae being the most common class, having the highest number in fish-fed diets (7805.67 organism/ml). The study revealed that LYFSB significantly influenced the zooplankton community, with protozoa dominating in biofloc water and rotifer in tilapia gut. LYFSB10 % and LYFSB20 % had the highest bacteria counts. Fish fed with LYFSB10 % and LYFSB20 % diets showed the highest values for specific growth rate (2.51 % day−1) and weight gain (24.92 g fish−1). These diets also exhibited increased activity levels of trypsin, lipase, and amylase enzymes. Increasing the inclusion of LYFSB in fish diets as a replacement for FM improved the intestinal and liver health of fish. The diets with LYFSB10 % and LYFSB20 % showed the highest levels of globulin, total protein, albumin, and IgM, with no significant differences between them. Fish fed LYFSB10 % had lower cholesterol and triglyceride levels. Superoxide dismutase (SOD) and catalase (CAT) activities were highest in fish fed LYFSB10 % and LYFSB20 %, while malondialdehyde (MDA) activity was lowest in the LYFSB30 % diet. The study showed that the biofloc system enhanced water quality and increased the efficiency of tilapia fed LYFSB10 % and LYFSB20 %.

Combined Dietary Spirulina platensis and Citrus limon Essential Oil Enhances the Growth, Immunity, Antioxidant Capacity and Intestinal Health of Nile Tilapia.

The dietary presence of feed additives is crucial for boosting fish growth and immunity. Accordingly, this feeding trial aimed to investigate the effects of the separate and concurrent dietary supplementation of Spirulina platensis (SP) and bitter lemon (Citrus limon) peel essential oil (LEO) on the growth, immunity, antioxidant capacity, and intestinal health of Nile tilapia (Oreochromis niloticus). Four groups of male Nile tilapia were employed. The first group (control) was given the basal diet, while the second and third groups received the basal diet supplemented with LEO extract (1%) and SP (1 g/kg diet), respectively. The fourth group received the basal diet supplemented with a mix of LEO (1%) and SP at 1 g/kg. After two months of feeding, using LEO or/and SP improved the overall growth and immunological parameters, with their combination yielding the best outcomes. The supplementation of LEO or/and SP improved the Nile tilapia's growth metrics and transcriptomic levels of growth-regulating genes such as (oligo-peptide transporter 1 (Pep1), growth hormone receptors 1 (GHR1), and insulin-like growth factor (IGF1). The improved growth performance was linked to significant increases in the expression levels of mucin and fat metabolism-related genes. Moreover, fish supplemented with LEO, SP, or their combination showed enhanced non-specific immunological measures, including phagocytic and lysozyme activities and the mRNA copies of its regulating genes. Additionally, remarkable increases in the antioxidant enzyme activities and the mRNA levels of their related genes were detected. The complement (C3) gene's transcriptomic level was also significantly increased. Furthermore, the dietary supplementation of LEO, SP, or their combination improved the histological structures of the spleen, hepatopancreas, and intestine. The enhanced effects of LEO, SP, or their combination on fish immunity and growth are suggested to be due to their contents of bioactive compounds with anti-inflammatory, antioxidant, and antimicrobial properties. Thus, using the LOE and SP blends as feed additives is recommended for better growth and immunity of Nile tilapia.

Effects on the productivity, haematological indices, and carcass quality of Nile tilapia reared at different stocking densities in a hybrid biofloc-RAS

The performance at varied over-stocking of Oreochromis niloticus was evaluated in a hybrid biofloc-recirculating aquaculture system (HBR) viz., 150 fish/m3 (HBR-SD150), 200 fish/m3 (HBR-SD200), 250 fish/m3 (HBR- SD250), and 300 fish/m3 (HBR- SD300) along with 150 fish/m3 (BFT-SD150) and 150 fish/m3 (RAS-SD150) each maintained in triplicate. Tapioca flour was used to maintain the carbon to nitrogen ratio of 15:1 within the HBR and BFT units throughout the experimental period of 120 days. At the conclusion of the experiment, assessments were made of productivity, biological and haematological indices; and proximate composition of the fish and the floc. Evern though significantly higher productivity was observed in HBR-SD200, a quadratic regression model applied to the productivity as a function of stocking density {Stocking density (fish/m3) = −21.008 × 2 + 532.15× - 3090.2, R2 = 0.6929} and the optimum productivity for O. niloticus (Nile tilapia) found to be 13.2 Kg/m3 at 229.89 fish/m3. Notably, HBR-SD150 groups exhibited significantly higher levels of haematological indices including NBT. The Proximate composition of the floc revealed that a significantly higher quantity of protein and ash was found in HBR-SD150 and HBR-SD300, respectively. There was no significant difference in carcass composition of Nile tilapia across the treatments except for that of crude protein levels. Profitability analysis demonstrated that low stocking density groups achieved greater profits than high stocking density HBR and control. The findings of present study indicate that the maximum production that can be accomplished from the HBR culture system is 13.2 Kg/m3 at a density of 229.89 fish/m3 without affecting the growth, immunity, and survival of Nile tilapia.

Assessing the effects of N-acetyl cysteine on growth, antioxidant and immune response in tilapia (Oreochromis niloticus) under different regimes of stocking densities.

The study investigated the impact of N-acetyl cysteine on growth, immune response, and antioxidant activity in tilapia (Oreochromis niloticus). Fish were reared at three densities (1.50, 3.00, and 4.50 kg/m3) with four levels of N-acetyl cysteine supplementation (0, 2, 4, and 6 mg/kg) over 60 days. Better growth was observed at low density, but at all densities, fish fed the highest N-acetyl cysteine level (6 mg/kg) showed improved growth. Chemical composition of fish and activity of amylase, lipase and protease in all treatments were noted to be insignificant. The levels of antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and cortisol in HD treatments were high as compared to LD and MD treatment. However, fish fed with N3 diet in each density treatment showed the lowest level of antioxidant enzymes as well as cortisol. Similarly, the levels of malondialdehyde were noted to be high at HD treatments as compared to that in LD and MD. Its levels were lower in fish fed with N3 diets in all density treatments. Expression of somatostatins-1 did not increase in MD and HD treatments in response to high stocking density when compared with LD treatment. However, pro-opiomelanocortin-α level was reduced after N3 diet in HD treatment and interleukin 1-β expression increased after N3 supplement in HD treatment. In conclusion, N-acetyl cysteine supplementation improved growth and antioxidant response in tilapia. The most optimum dose of N-acetyl cysteine was noted to be 6 mg/kg at high stocking, suggesting the potential role of this nutraceutical in tilapia intensive culture.

Effects of passion fruit peel (Passiflora edulis) pectin and red yeast (Sporodiobolus pararoseus) cells on growth, immunity, intestinal morphology, gene expression, and gut microbiota in Nile tilapia (Oreochromis niloticus)

This study explores the effects of dietary supplementation with passion fruit peel pectin (Passiflora edulis) and red yeast cell walls (Sporidiobolus pararoseus) on growth performance, immunity, intestinal morphology, gene expression, and gut microbiota of Nile tilapia (Oreochromis niloticus). Nile tilapia with an initial body weight of approximately 15 ± 0.06 g were fed four isonitrogenous (29.09–29.94%), isolipidic (3.01–4.28%), and isoenergetic (4119–4214 Cal/g) diets containing 0 g kg−1 pectin or red yeast cell walls (T1 - Control), 10 g kg−1 pectin (T2), 10 g kg−1 red yeast (T3), and a combination of 10 g kg−1 pectin and 10 g kg−1 red yeast (T4) for 8 weeks. Growth rates and immune responses were assessed at 4 and 8 weeks, while histology, relative immune and antioxidant gene expression, and gut microbiota analysis were conducted after 8 weeks of feeding. The results showed that the combined supplementation (T4) significantly enhanced growth performance metrics, including final weight, weight gain, specific growth rate, and feed conversion ratio, particularly by week 8, compared to T1, T2, and T3 (P < 0.05). Immunological assessments revealed increased lysozyme and peroxidase activities in both skin mucus and serum, with the T4 group showing the most pronounced improvements. Additionally, antioxidant and immune-related gene expression, including glutathione peroxidase (GPX), glutathione reductase (GSR), and interleukin-1 (IL1), were upregulated in the gut, while intestinal morphology exhibited improved villus height and width. Gut microbiota analysis indicated increased alpha and beta diversity, with a notable rise in beneficial phyla such as Actinobacteriota and Firmicutes in the supplemented groups. These findings suggest that the combined use of pectin and red yeast cell walls as prebiotics in aquaculture can enhance the health and growth of Nile tilapia, offering a promising alternative to traditional practices. Further research is needed to determine optimal dosages for maximizing these benefits.

Dietary biogenic selenium nanoparticles improve growth and immune-antioxidant indices without inducing inflammatory responses in Nile tilapia

The present study evaluated the use of green-synthesized selenium nanoparticles (SeNPs), using the microalgae Pediastrum boryanum as a diet additive in aquaculture to improve the growth performance, health, and immune response of Nile tilapia. Nile tilapia were fed different concentrations of green SeNPs (79.26 nm) as follows: 0, 0.75, and 1.5 mg/kg of SeNPs for 8 weeks. Following the trial, growth performance, biochemical indices, antioxidant and pro-inflammatory cytokine-related genes, and tissue histological examinations were performed. The study showed that SeNPs significantly improved (P < 0.05) growth performance and innate immune parameters (P < 0.001, IgM, and lysozyme) at both supplemented doses compared with the control. The protein profile and liver function enzymes were normal compared with those in the control group (P > 0.05). Serum malondialdehyde and superoxide dismutase levels were not significantly changed, while reduced glutathione and catalase were significantly enhanced (P < 0.01, P < 0.05) in the SeNPs 1.5 mg/kg compared to the control group. No inflammatory response was detected upon SeNP supplementation, as indicated by the absence of changes in the expression of pro-inflammatory cytokine genes. The earlier assays’ results were histopathologically evidenced, where hepatic and splenic tissue architectures in SeNPs groups did not reveal any deviation from the control group. Our findings indicate that green selenium nanoparticles can potentially improve the growth and immunological response of Nile tilapia, offering opportunities for incorporating health benefits into functional foods and nutraceuticals, which corresponds to the increasing consumer interest in eco-friendly, environmentally sustainable dietary supplements.

Impacts of substituting fish meal with full-fat or defatted black soldier fly (Hermetia illucens) larvae on growth, quality, and health of Nile tilapia (Oreochromis niloticus) fingerlings

This study investigated the use of black soldier fly (Hermetia illucens) larvae (BSFL), provided in either full-fat (FBSF) or defatted (DBSF) forms, as an alternative protein source in the diet of Nile tilapia (Oreochromis niloticus) fingerlings. Specifically, the influence was assessed of BSFL on growth performance, hematological parameters, body composition, and histology. Nine diets (including the control) were formulated to be isonitrogenous (35 % crude protein) and isolipidic (6 % crude lipid), relying on fish meal as the primary protein source and gradually replacing it with BSFL meal at levels of 25 %, 50 %, 75 %, or 100 % on an equivalent protein basis, corresponding to dietary inclusion levels of 5.25 %, 10.25 %, 15.5 %, and 20.0 %, respectively. Fish with an initial mean weight ± standard deviation of 1.3 ± 0.26 g were fed for 12 weeks until the fish final weight was in the range 24.08–34.95 g. Based on the results, there were no significant (p>0.05) differences in the growth performance or feed conversion ratios among the treatments. Additionally, there were no significant differences in the hematological responses or the proximate body composition. Furthermore, 100 % substitution of fish meal with FSFL and DBSF meal caused blood congestion in the hepatopancreas region and several intraepithelial leukocytes in the intestine. There were no detrimental impacts at levels of 25 %, 50 %, and 75 % on growth performance, hematological responses, body composition, or the intestines or liver histological characteristics of the O. niloticus fingerlings. This information should provide useful guidance for the management of Nile tilapia, an economically important species.

Influence of raceway based biofloc system on the growth and physiological responses of Penaeus vannamei and GIF tilapia in a polyculture model – BFT aquaculture system

The present study investigates the efficiency of raceway-based biofloc technology for the production of Penaeus vannamei and Genetically Improved Farmed tilapia in a polyculture model. Six raceway tanks were used to explore the growth performance, digestive enzyme activities, bacterial count and histology of P. vannamei reared with GIF tilapia using raceway-based biofloc and clear water raceway culture systems. Each raceway (6.8 m x 2.2 m x 3 m) was stocked with 60 shrimp/m3 of P. vannamei (0.93±0.09 g), and 5 fish/m3 of GIF tilapia (0.42±0.01 g) and reared for 90 days. Biofloc, with a carbon: nitrogen ratio of 15:1, is developed and maintained using soyahull pellet powder as organic carbon source, with continuous aeration was provided. The present study found significantly higher weight gain of P. vannamei (16.09±0.26 g) and GIF tilapia (11.71±0.35 g) in raceway-based biofloc culture system. Survival of P. vannamei and GIF tilapia did not exhibit any significant variations between raceway-based biofloc and clear water raceway systems. Significantly higher digestive enzymes activities of protease (0.25±0.01 and 0.14±0.02 U/ mg protein/min), lipase (0.88±0.04 and 0.37±0.01 U/ mg protein/min) and amylase (0.008±0.00 and 0.0016±0.00 U/ mg protein/min) are recorded in P. vannamei and GIF tilapia in raceway-based biofloc culture system, respectively. Higher values of total heterotrophic bacteria (52.25±0.88×104 CFU/ml, 49.63±1.10 ×107 CFU/g and 53.12±0.44×107 CFU/g) and bacillus counts (76.50±0.46×102 CFU/ml, 155.62±0.89×102 CFU/g and 238.75±0.82×102 CFU/g) are recorded in culture water, P.vannamei gut and GIF tilapia gut in raceway based biofloc culture system, respectively. No histopathological changes are observed in the GIF tilapia (gut), P. vannamei (gut and hepatopancreas), but deformities such as congestion of the tips of few secondary lamellae are noticed in the GIF tilapia (gill) reared in the clear water raceway system. Therefore, the study suggests that polyculture of P. vannamei and GIF tilapia in a raceway-based biofloc system is advantageous over the clear water raceway system in terms of production augmentation with improved physiological conditions.