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

The main objective of the current trial was to investigate the impacts of tilapia diets supplemented with S-methylmethionine sulfonium chloride (MMSC) on the growth performance, feed efficiency, body analysis, blood biochemistry and regulation of myostatin (MSTN) and insulin-like growth factor-1 (IGF-1) genes of nile tilapia (Oreochromis niloticus). The experimental fish (n=180) weighing 22.4±0.17 g were allocated randomly into three equal groups in triplicate as follows; the control group received an un-supplemented diet; the other two groups received two different levels of MMSC (0.2 and 0.4 g/kg) for eight weeks. The obtained findings demonstrated that tilapia diets enriched with small dosages of MMSC considerably (P<0.05) enhanced all assessed growth performance and feed efficiency indicators when compared with the control group. When compared to the control group, tilapia meals supplemented with 0.2 g MMSC significantly (P<0.05 or 0.01) raised blood protein profile, particularly total protein and globulin levels. Contrarily, blood creatinine levels were significantly (P<0.01) reduced in the group of tilapia fed diets containing MMSC (0.2 or 0.4 g/kg) compared to the group without receiving any supplementation. Whereas, fish body analysis showed higher significant increases in crude protein and ether extract levels (P<0.01) as well as reduced ash content (P<0.05) in the fish group that received lower MMSC doses in comparison to other treated and control groups. In addition, MMSC dietary supplementation significantly downregulated the expression of MSTN and upregulated IGF-1 mRNA expression compared with the control group. Additionally, both dosages of MMSC supplementation modestly enhanced the intestinal villus histomorphometric score indices with observed tall, thick, and various broad tips in comparison to the control group. In conclusion, it could be recommended that fish diets supplemented with 0.2 g MMSC per kg diet may promote the growth and general health status of Nile Tilapia. [ABSTRACT FROM AUTHOR]

This study evaluated how water temperature (26, 28, and 30°C), number of meals per day (one or two meals), and protein percent in diet (20, 25 and 30%) impact growth performance, biometric indices, and feeding behavior of Nile tilapia, Oreochromis niloticus. Fish were randomly allocated into 18 equal replicate groups. Higher final body weight was observed in fish reared at 30°C and fed one meal per day containing 30% crude protein. Better weight gain, weight gain %, feed conversion ratio, specific growth rate, and condition factor were recorded in fish reared at 26°C and fed one meal per day containing 30% protein. The best length weight relationship was obtained in fish reared at 26°C and fed one meal per day containing 30% crude protein. Shorter feeding duration and duration of appetite inhibition latency were recorded in fish reared at 30°C, fed one meal per day, and given a diet containing 30% protein. The highest proactivity was recorded in fish reared at 30°C, received one meal per day, and with 25% crude protein in their diet. Conclusively, rearing Nile tilapia at 26–30°C with a lower feeding frequency (one meal/day) and a 30% crude protein diet achieved better performance and feeding behavior. [ABSTRACT FROM AUTHOR]

Effects of dietary supplementation of Tribulus terrestris (TT) and 17α‐methyl testosterone (MT) on growth performance and reproductive efficiency of male Nile tilapia, Oreochromis niloticus (N = 75, initial weight 60 ± 3.251 g), were evaluated. Five experimental treatments in triplicate were fed on basal diet (30% crude protein) (control group, CG), basal diet containing 60 mg MT (MT group) and basal diet containing 250, 500 and 750 mg/kg diet TT (TT250, TT500 and TT750 groups), respectively, for consecutive 45 days. Results revealed that the fish received TT in diet showed better growth performance (final body weight, weight gain, feed conversion ratio, specific growth rate, testes weight and gonadosomatic index) compared with MT and CG (p <.05), as well as for haemoglobin content and red blood cell count (p <.05). The highest level of testosterone, 11‐keto testosterone, sperm concentration and vitality was recorded in TT750 followed by TT500, TT250 and MT groups, while the lowest value was recorded in the CG (p <.05). The highest seminiferous tubule diameter was recorded in TT750 followed by TT500, TT250 and CG, while the lowest diameter was recorded in the MT group (p <.05). Fish received TT showed normal dilated seminiferous tubule filled with large amount of free sperms within their lumen in a dose related effect. In conclusion, male Nile tilapia dietary supplementation with different inclusions of Tribulus terrestris extract specially 500 and 750 mg/kg diet improves growth performance, health condition, semen quality and reproductive efficiency without any harmful effect on water quality. [ABSTRACT FROM AUTHOR]

Effects of dietary supplementation of Bifidobacterium longhum, Bifidobacterium thermophilum, Bacillus subtilis, and Lactobacillus acidophilus on growth performance, health condition, body chemical composition, and water quality of Nile tilapia (Oreochromis niloticus) fingerlings were evaluated. Five experimental treatments in triplicate were fed a diet containing 30% crude protein supplemented with variable inclusion of bacterial mixture: control, T1, T2, T3, and T4 containing 0, 1.0, 2.0, 3.0, and 4.0 g bacterial mixture/kg diet, respectively. Fish fed the T4 diet had the highest final body weight, weight gain, specific growth rate, thermal growth coefficient, feed intake, and the best feed conversion ratio. No significant differences in body chemical composition of fish were observed in terms of dry matter, crude protein, lipid, ash, and energy content among all treatments. Probiotic supplementation showed no noticeable differences on haematological and biochemical blood parameters, except for packed cell volume, albumin, albumin/globulin ratio, aspartate transaminase, glucose, uric acid, triglycerides, and cholesterol. Conclusively, Nile tilapia fingerlings diet supplemented with evaluated probiotic with an optimal dietary supplementation of 4 g/kg diet improved growth performance and fish health without a negative impact on water quality. This supplementation could therefore be used as a probiotic in Nile tilapia fingerlings diet. [ABSTRACT FROM AUTHOR]

In the present study sodium carbonate peroxyhydrate (2Na2CO3.3H2O2) which is considered as eligible algaecide and fungicide, was used as an alternative source of oxygen in fish ponds with concentration of 50 and 100 mg/L for 10 days. To approach our target hematological (RBCs, Hb, PCV, total and differential leukocytic count) together with several serum biochemical parameters as (glucose, total proteins, albumin, globulins, A/G, amino transferases (ALT, AST), urea and creatinine) were estimated. DNA fragmentation and a mild degree of DNA degradation as shown by DNA smear and a hallmark apoptosis were observed in samples from gills, brain and liver after 6 days of the experiment. Pathological changes started to appear first in the brain tissue then other organs (liver and kidney) were also affected after 6 days of the experiment with 100mg/L treated groups indicating the sensitivity of the brain and the direct effect of hypoxia on this organ. These results suggest the resistance of fish to oxygen depletion in case of using sodium carbonate peroxyhydrate (OXY-SOS) and the appearance of pathological changes after 6 days of use indicate its efficiency as alternative oxygen source. Thus, sodium carbonate peroxyhydrate (OXY-SOS) can be used as a stable oxygen releaser and as a suitable alternative to artificial aeration in fish farms for a period up to 6 days without adverse effect on treated fish. [ABSTRACT FROM AUTHOR]

Four diets were formulated to include different sources of animal by-products as a protein source in Nile tilapia (5.79 ± 0.05 g) diets. The first group fed diet containing fish meal (T1), while the 2nd, 3rd and 4th groups fed a mixture of poultry by-product meal (PBM), animal by-product meal (ABM) and kitchen waste meal (KWM) at 50:25:25 (T2); 25:50:25 (T3) and 25:25:50 (T4) ratio, respectively. All diets were formulated to be isonitrogenous and isolipidic. After 120 days, apparent digestibility and growth parameters were measured. The obtained results revealed that, the chemical composition of fish meal had the highest value of protein followed by PBM and KWM. Fish meal had higher essential amino acids content, except for the threonine and arginine amino acids, followed by PBM and ABM. The highest apparent digestibility of crude protein and ether extract were recorded in T1 and T2 followed by T4 and T3 groups. T1 and T2 groups exhibited significantly (P<0.05) the highest growth performance over fish fed T3 and T4 diets. It could be suggested that using of waste protein sources especially containing high PBM as a replacement for fish meal to reduce the feed cost per Kg fish Production [ABSTRACT FROM AUTHOR]

High stocking density is significantly disturbing the growth and productivity of aquatic animals. Digestive enzymes, immunity and oxidative status of Nile tilapia were investigated in case of culturing in several densities. Fish (14.3±0.03 g) were stocked in 12 aquaria (70 L) at four densities of 10 (SD10), 20 (SD20), 30 (SD30) and 40 (SD40) fish per aquarium for 30 days. Fish growth, feed efficiency ratio, digestive enzyme activity and dissolved water oxygen significantly (P<0.05) decreased, while the total ammonia increased with increasing stocking density. Immunoglobulin and NBT levels decreased significantly (P<0.05) in SD40 set compared to SD20 set without no differences with the other two groups. Lysozyme activity reported the highest significant (P<0.05) values in SD10 and SD20 groups over the high stocking density group (SD40) without no difference with SD30 group. Bactericidal, phagocytic activities and phagocytic index reported significantly (P<0.05) lower values in fish reared in SD30 and SD40 groups than fish reared in SD10 and SD20 groups. Peroxidase activity also showed significantly (P<0.05) low values in SD40 and SD30 groups with the weakest activity in SD40 group. Total serum protein lowered relatively in SD30 and SD40 groups without no differences with the other groups. Furthermore, fish reared at high stocking densities resulted in significantly (P<0.05) decreased superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities as well as increased malonaldehyde (MDA) activity in blood of tilapia suggesting suppressed antioxidant response. In conclusion, intensive conditions depressed the growth, digestive enzyme activity, immunity and oxidative status of Nile tilapia. [ABSTRACT FROM AUTHOR]