Methyltestosterone Research Articles

Comparable to 17α- methyl testosterone, dietary supplements of Tribulus terrestris and Mucuna pruriens promote the development of mono-sex, all-male tilapia fry, growth, survival rate and sex-related genes (Amh, Sox9, Foxl2, Dmrt1)

To evaluate Tribulus terrestris and Mucuna pruriens for inducing all-male tilapia, mixed-sex Nile tilapia, Oreochromis niloticus, (mean weight 0.025 ± 0.009 g; mean length 1.25 ± 0.012 cm), were given a meal supplemented with either T. terrestris powder (commercial fish feed, 40% crude protein) (TT group), M. pruriens seed extract (MP group), MP + TT (mixed group), 17α-methyl testosterone (MT, control positive), or without supplements (control negative). The MP extracts significantly increased (P < 0.05) the final weight, weight gain, weight gain rate, and specific growth rate while feed conversion ratio was significantly decreased (P < 0.05). Plant extracts markedly improved (P < 0.05) the survival rate, proportion of males, and total testosterone compared to control and MT. Estrogen levels were lower in groups with plant extract than other groups. Fifteen days post-feeding, the Amh gene was expressed in the brain of O. niloticus fries with higher levels in MP, TT, and MT groups. Additionally, the expression of the Sox9 and Dmrt1 genes as a male related genes in fish fry gonads revealed significantly (P < 0.05) higher levels in groups fed on MP, TT, and MT compared to control after 30-day post-feeding, whereas; Foxl2 gene expression as a female related gene was significantly (P < 0.05) lower in fish fed on MP, TT, and MT compared to other groups after 30 days post feeding. Histologically, MT, MP, TT, and the mixture all exhibited solely male reproductive traits without noticeable abnormalities. This study concluded that each of the TT or MP extracts can induce sex reversal in tilapia while having no negative health impact compared to MT as the growth and survival rate in the treated groups with TT and MP were higher than control and group treated with MT.

Characterization and quantitation of a sulfoconjugated metabolite for detection of methyltestosterone misuse and direct identification by LC-MS

Methyltestosterone (MT) is one of the most frequently misused anabolic androgenic steroids detected in doping control analysis. The metabolism of MT in humans leads to several phase І metabolites and their corresponding phase Ⅱ conjugates. Previous studies have postulated the 3α-sulfoconjugate of 17α-methyl-5β-androstane-3α,17β-diol (S2) as principal sulfate metabolite of MT, with a detection window exceeding 10 days. However, a final direct and unambiguous confirmation of the structure of this metabolite is missing until now. In this study, we established an approach to detect and identify S2, using intact analysis by liquid chromatography hyphenated with tandem mass spectrometry (LC-MS/MS) without complex sample pretreatment. An in vitro study yielded the LC-MS/MS reference retention times of all 3-sulfated 17-methylandrostane-3,17-diol diastereomers, allowing for accurate structure assignment of potentially detected metabolites. In an in vivo excretion study with a single healthy male volunteer, the presence of the metabolite S2 was confirmed after a single oral dose of 10 mg MT. The reference standard was chemically synthesized, characterized by accurate mass mass spectrometry (MS) and nuclear magnetic resonance (NMR), and quantified by quantitative NMR (qNMR). Thus, this study finally provides accurate structure information on the S2 metabolite and a direct analytical method for detection of MT misuse. The availability of the reference material is expected to facilitate further evaluation and subsequent analytical method validation in anti-doping research.

Analyzing the impact of synthetic and natural steroids: a study of cytochrome P450 metabolism, morphological alterations through metabolomics, and histopathological Examination

This study focuses on the comparative metabolic profiling and effects of two steroid types: natural and synthetic, specifically 17α-methyl testosterone (17α-MT) at varying concentrations (1.5, 2, and 3 mg/kg) in rainbow trout (Oncorhynchus mykiss). Over a 75-day feeding trial, growth metrics, such as feed efficiency, daily specific growth, live weight gain, total weight gain, and survival rate were systematically monitored every 15 days. At the end of the feeding trial, histopathology, immunohistochemistry, and metabolome analyses were performed in the high-concentration groups (3 mg/kg natural and 3 mg/kg synthetic), in which the lowest survival rate was determined. Key findings reveal that the type of hormone significantly influences growth parameters. While some natural steroids enhanced certain growth aspects, synthetic variants often yielded better results. The metabolomic analysis highlighted significant shifts in the metabolism of tryptophan, purine, folate, primary bile acids, phosphonates, phosphinates, and xenobiotics via cytochrome P450 pathways. Histopathologically, the natural hormone groups showed similar testicular, hepatic, muscular, gill, cerebral, renal, and intestinal tissue structures to the control, with minor DNA damage and apoptosis observed through immunohistochemistry. Conversely, the synthetic hormone groups exhibited moderate DNA damage and mild degenerative and necrotic changes in histopathology.

Formation of Male Sex Tilapia Larvae (Oreochromis niloticus) Using Natural Methyltestosterone Hormone

Aims: Obtaining a productive tilapia, by changing the sex of the tilapia larvae into male monosex. This was achieved by determining the effect of the duration of administrating the natural methyltestosterone (MT) hormone on the male sex of tilapia using the Immersion method.&#x0D; Methodology: The study was conducted at the Northern Region Marine and Fisheries Service Branch, Wanayasa Freshwater Fish Seed Development Center, Purwakarta Regency, West Java Province, Indonesia. The experimental design used a completely randomized design (CRD) with 5 treatments and 3 replications. The study used the Immersion method where untreated tilapia and the four hormones tilapia. The treatments are as follows:&#x0D; A = untreated tilapia&#x0D; B = tilapia treated in 17a-MT (5h-100mg/L)&#x0D; C = tilapia treated in MT (5h-350mg/L)&#x0D; D = tilapia treated in MT (10h-350mg/L)&#x0D; E = tilapia treated in MT (15h-350mg/L)&#x0D; Results: Tilapia larvae used were aged 6 days after hatching and reared for 40 days, then the male and SR sex were observed. The results of this study showed that the duration of immersion of tilapia larvae using natural MT significantly affected the male tilapia which resulted in the highest male percentage at 15 h of immersion of 80.2%, then followed by 10-h immersion of 75.6% with the same SR value of about 90%.&#x0D; Conclusion: Administration of natural MT using cow testis meal by immersion method at different durations significantly affects male sexual development in 6-day-old tilapia larvae. Based on the obtained data analyses, the percentage of male tilapia in the 40-day experimental study shows the most effective duration in treatment E (15 h) with a measure of 350 mg/l, which is 80.2%. Further studies regarding the relationship between sex change and the growth of sex-changed fish as an effect of immersion duration.

Sex Ratio and production parameters of Oreochromis niloticus “Tilapia”

Oreochromis niloticus farming has been affected by excessive reproduction in cropping systems, which causes delayed growth and small sizes at harvest, becoming unmarketable, creating the need to reverse the sex of the females, being possible with hormonal sex reversal techniques such as 17 α methyltestosterone (MT). The objective of this research was to determine the sexual ratio and obtain the production parameters in specimens of O. niloticus with the MT hormone which was supplied in food at 45% protein, with a dose of 24 mg of MT/kg of food, for 28 days. Sex determination was carried out using the squash technique and microscope observation. The information was analyzed using descriptive and inferential statistics at 95% confidence in the Excel program. We worked with 10% of the total population, reaching 95.2% males. The gonads of the females showed oocytes, while in the gonads of males’ spermatocytes were observed, they presented a survival of 96.33%, an increase in weight of 13.46 g and length of 7.82 cm.

Effects of exogenous steroid hormones on growth, body color, and gonadal development in the Opsariichthys bidens.

To investigate the effects of exogenous steroid hormones on growth, body color, and gonadal development in the Opsariichthys bidens (O. bidens), synthetic methyltestosterone (MT) and 17β-estradiol (E2) were used for 28 days' treatment of 4-month-old O. bidens before the breeding season. Our results suggested that MT had a significant growth-promoting effect (P < 0.05), whereas E2 played an inhibitory role. On the body surface, the females in the MT group showed gray stripes, and the fish in other groups showed no obvious stripes. The males with MT treatment displayed brighter blue-green stripes compared to the CK and E2 groups. The histological analysis showed that the MT significantly promoted testes development in males, blocked oocyte development, and caused massive apoptosis in females, whereas the E2 group promoted ovarian development and inhibited testes development. Based on qRT-PCR analysis, in females, the expression of igf-1, dmrt1, and cyp19a1a genes revealed that E2 treatment resulted in down-regulation of igf-1 expression and up-regulation of cyp19a1a expression. In males, igf-1 and dmrt1 were significantly up-regulated after MT treatment, and E2 treatment led to down-regulation of igf-1. Therefore, this study demonstrates that MT and E2 play an important role in reversing the morphological sex characteristics of females and males.

In Silico Study of Corticosteroids Drugs

Molecular Docking has become an important component of the drug discovery process. Since first being developed in the 1980s, advancements in the power of computer hardware and the increasing number of and ease of access to small molecule and protein structures have contributed to the development of improved methods, making docking more popular in both industrial and academic settings. In this research Molecular Docking we are perform on triamcinolone and methyl testosterone by using Autodock and Discovery Studio software. QSAR study revealsed that substitution of different electron donating or withdrawing group at different position on triamcinolone and methyl testosterone lead nucleus elaborate change in pharmacological activity. Molecular Docking done by substituting or replacing different group at different position affected the potency of drug on addition of hydroxy, Methyl at different position where reduced the potency of triamcinolone while addition of ether or ester group enhance the potency of triamcinolone. In methyl testosterone, introduction of heterocyclic system into a steroidal nucleus in ring A enhances the potency while removal of hydroxy group, addition of O atom reduces the potency.

Ovarian Histology and Histopathology of Olive Barb, Puntius sarana Exposed to Endocrine Disrupting Chemical (17-Α Methyl Testosterone) in Laboratory Condition

17-α methyl testosterone is a major endocrine disrupting chemical (EDCs), reported harmful effect on endocrine system of aquatic animals. To study the impact of 17-αMT on olive barb (Puntius sarana) gonad, sixty fishes were collected for in vitro experiment. Hormonal treatments were carried out 90 days with three distinct hormonal dosages (T1:40 mg/kg; T2:60 mg/kg and T3:90 mg/kg) mixed with pelleted feed and no hormone in control tank (C). Each 30 days intervals, histological analysis was performed to observe alterations in the gonad due to the effect of 17α-MT. Four gamete developmental stages of female P. sarana ovary were identified through microscopic examination named immature, previtellogenic, vitellogenic and mature stage. Mild to moderate histological abnormalities has been observed in ovary for different treatments. T1 showed apparently normal histology except some alterations like empty follicle (ef), lipid droplet (ld), vitelline envelop breakdown (veb), but pronounced alterations were detected at higher concentration T2 and T3, increasing with longer exposures for instance degenerated nucleus (dn), atretic follicle (af), thickened vitelline envelop (tve), residual oocyte (roc). This preliminary study revealed more profound responses to EDCs exposure in the olive barbs which could serve as a model bio-indicator in ecotoxicological study.

Sexual differentiation and sex reversal in tilapia (Oreochromis niloticus) by hormone 17 α methyltestosterone similar to that used in cultivation systems

The hormone 17 α methyltestosterone (MT) is commonly used in the farming of tilapia, which is a gonochoristic species, for the obtainment of a male mono-sex population to avoid reproduction during grow-out and due to the fact that males present greater growth, making cultivation commercially more lucrative. Larvae were collected and experimentally received MT in the feed for 30 days in a similar way as that performed in commercial farming. Physiological events of sexual differentiation and the moment in which sex reversal promoted by MT occurred were documented with the use of histological and morphometric methods. On the first day of receiving feed with MT, the fish presented gonads with undifferentiated germ cells. On the 12th day of exogenous feeding with and without MT, sexual differentiation of the gonads was observed morphologically, demonstrated by the formation of the ovarian cavity in females. Males continued to have undifferentiated gonads for a longer period. Sex reversal occurred in all females treated with MT at 25 days after the onset of exogenous feeding. The results indicate that treatment for sex reversal used in commercial farming systems could be shorter than that customarily employed, diminishing the quantity of synthetic hormone released into the environment and reducing the harmful effects of MT on other aquatic organisms. Therefore, the data suggest the possibility of reducing the use of hormone MT by 5 days.

Multiplex lateral flow immunochromatographic assay for the qualitative and quantitative detection of six steroid hormone residues in chicken and pork

To ensure food safety from animal origins and to prevent potential hazards caused by steroid hormones, there is an urgent need to develop a rapid detection method for steroid hormones in foods from animal origins. Three highly sensitive monoclonal antibodies (mAb) against testosterone propionate (Tp), stazolol (STA) and estradiol benzoate (EB) were prepared, with IC50 values of 0.13, 0.14 and 0.19 ng/mL, respectively. Tp-mAb is a group-selective mAb that simultaneously detects Tp, testosterone (T), methyltestosterone (MT) and testosterone phenylpropionate (TPP), and their IC50 values were 0.13, 0.77, 0.90, and 1.25 ng/mL, respectively. A novel multiplex lateral flow immunochromatographic strip (ICS) was further prepared, which could simultaneously detect Tp, STA, and EB in chicken and pork samples with limits of quantification (LOQ) of 0.32, 0.51, 0.35 μg/kg and 0.36, 0.64, 0.43 μg/kg, respectively. Based on the broad spectrum of Tp-mAb, ICS has been further developed to detect Tp, T, MT and TPP simultaneously. This multiplex ICS rapid detection method was efficient, sensitive, and fast, for the simultaneous detection of multiple steroid hormones in actual samples. Its detection time is only 40 min, which it represents a favorable monitoring tool for the detection of steroid hormones in animal-derived foods from the marketplace.

Immersion in sea cucumber’s steroid extract to increase male production of juvenile freshwater crayfish

One of the ways to increase the production for aquaculture is through the cultivation of monosexuals by ensuring genital reversal from which energy for reproduction is diverted towards growth. Masculinization has been identified as one of the most prominent techniques, where sex development was directed from female to male. This approach only altered the phenotype and not the genotype. The red claw crayfish (Cherax quadricarinatus) was a relatively new commercial commodity, and the males were known to grow faster than females. Hence, it was proposed to use monocultures comprising an all-male population to increase yield using steroid hormone, synthetic 17α-methyltestosterone. However, this technique generated residues that detrimentally affect human health, the environment, and cultivated organisms. Therefore, finding new safe natural steroid sources was essential, and one of which is exploring of natural hormones extracted from the viscera of sea cucumbers (Holothuria scabra Jaeger). This study focused on the determination of male formation and testosterone levels among juvenile crayfish, after immersing in sea cucumber steroid extract (SCSE). A completely random design with factorial was used with two variables, encompassing the varied doses (0, 2, 4 mg/L, 2 mg/L 17α-methyl testosterone as control group) and immersion times of 18 and 30 h. The result showed the dose-dependent ability of SCSE increase the male genital formation and promote the testosterone level of juvenile crayfish. In addition, the testosterone was influenced by dose and immersion duration time, with the highest level of testosterone observed in treatments of 4 mg/L SCSE with 30 h immersion was 0.248 ng/mL, while the male percentage was 77%. In conclusion, the combination of dose and immersion time significantly affected growth and testosterone levels.

Effect of natural and synthetic androgen hormone on sex reversal of Nile Tilapia (Oreochromis niloticus).

The present study aimed to produce a monosex population of all male Nile tilapia (Oreochromis spp.) using 17α-methyl testosterone and common carp testes (as a source of natural androgen). Trial was conducted into two consecutive phases, the first was fry (4-5 days old)administration with negative control (without hormone) and positive control (with hormone) feed viz., MT1:60mg/kg, MT2:70mg/kg (17α-MT), carp testis CT1:70% and CT2:80% for 30 days to reverse the sex of male fish and the second phase was nursing the fingerlings for two months on control diet (32% Crude protein).Results revealed a significant growth rate (P<0.05) in the control group where final weight (4.8±0.34ab) and weight gained was recorded as 0.66±0.03ac. In proximate chemical composition of body meat, CT2 treatment showed maximum retention of crude protein, crude fat, and ash whereas dry matter showed maximum retention in MT2 and CT1 treatments. Morphological and histological examination revealed significant difference (p<0.05) in phenotypic males of Nile tilapia fed with the highest percent in MT-treated diet (MT2) of 95±0.58a while MT1, CT2 and CT1 had males of 85±6.0b, 70±5.0b and 65±6.5b, respectively. It was concluded that synthetic androgen (17αMT) was more effective for masculinization but natural androgen scan be an alternative method to produce male tilapia population in an environment-friendly manner as they are inexpensive, eco-friendly, and radially available. These results suggested that synthetic and natural androgen supplementation in the diet plays a significant role in improving growth performance and body composition.

H2O2-Driven Hydroxylation of Steroids Catalyzed by Cytochrome P450 CYP105D18: Exploration of the Substrate Access Channel.

CYP105D18 supports H2O2 as an oxygen surrogate for catalysis well and shows high H2O2 resistance capacity. We report the hydroxylation of different steroids using H2O2 as a cosubstrate. Testosterone was regiospecifically hydroxylated to 2β-hydroxytestosterone. Based on the experimental data and molecular docking, we predicted that hydroxylation of methyl testosterone and nandrolone would occur at position 2 in the A-ring, while hydroxylation of androstenedione and adrenosterone was predicted to occur in the B-ring. Further, structure-guided rational design of the substrate access channel was performed with the mutagenesis of residues S63, R82, and F184. Among the mutants, S63A showed a marked decrease in product formation, while F184A showed a significant increase in product formation in testosterone, nandrolone, methyl testosterone, androstenedione, and adrenosterone. The catalytic efficiency (kcat/Km) toward testosterone was increased 1.36-fold in the F184A mutant over that in the wild-type enzyme. These findings might facilitate the potential use of CYP105D18 and further engineering to establish the basis of biotechnological applications. IMPORTANCE The structural modification of steroids is a challenging chemical reaction. Modifying the core ring and the side chain improves the biological activity of steroids. In particular, bacterial cytochrome P450s are used as promiscuous enzymes for the activation of nonreactive carbons of steroids. In the present work, we reported the H2O2-mediated hydroxylation of steroids by CYP105D18, which also overcomes the use of expensive cofactors. Further, exploring the substrate access channel and modifying the bulky amino acid F184A increase substrate conversion while modifying the substrate recognizing amino acid S63 markedly decreases product formation. Exploring the substrate access channel and the rational design of CYP105D18 can improve the substrate conversion, which facilitates the engineering of P450s for industrial application.

Hormonal Sex Inversion by 17α-Methyl testosterone in common carp (Cyprinus carpio) through egg Immersion Technique (IT)

ABSTRACT The trial was conducted to evaluating the effect of different hormone concentrations of 17α-methyltestosterone @ (HC): (200, 400, 600, and 800 μg/L−1), immersion times (IT): 48, 60 and 72 h and the interaction effect of (HC × IT) on the hatching percentage of Cyprinus carpio egg, percent survival and percent of males. Results indicated that survival of treated fry was affected by the increasing IT (p < 0.001). The main interaction effect of HC × IT showed that the highest percent of male individuals 96% was attained at 800 μg/L HC at 72 h IT and lowest was recorded 49% in control (p < 0.05). Increased percent male of C. carpio was obtained with increasing HC across all IT. It is concluded that the immersion treatment at 800 µg/L for 72 h is more effective to change sex ratios of C. carpio. Masculinization of C. carpio by egg immersion is an alternative technique of oral method, manual sorting of sexes, gene manipulation and hybridization.

Simultaneous Analysis and Efficient Separation of Anabolic Androgenic Steroids in Dietary Supplement by a Validated HPTLC Method.

Using sports supplements is common among athletes. The presence of anabolic steroids in sports supplements as a hormonal contaminant can increase production efficiency. Since anabolic steroids cause health problems and result in positive doping tests in athletes, it is important to investigate their presence in the supplement preparations consumed by athletes. This paper aims to simultaneously determine ten anabolic steroids by high-performance thin-layer chromatography (HPTLC) method in sports supplements. Chromatographic analysis was conducted on glass silica gel 60F254 plates. The extracts loaded on silica gel plates are subjected to programed multiple development (PMD) to separate anabolic androgenic steroids (AASs). Densitometric scanning is carried out at the wavelength of 245 and 366nm. The method was validated according to the ICH guidelines. Spots at retardation factor (Rf) 0.72 (elution system 1), 0.4 (elution system 1), 0.29 (elution system 2), 0.25 (elution system 2), 0.1 (elution system 1), 0.65 (elution system 2), 0.59 (elution system 1), 0.44 (elution system 1), 0.8 (elution system 3), and 0.82 (elution system 3) values were recognized as 19-nor androstenedione, 19-nortestosterone, methyl testosterone, clostebol, stanozolol, trenbolone enanthate, oxymetholone, oxandrolone, testosterone enanthate, and nandrolone decanoate, respectively. The linear ranges were 25 - 250 μg/mL for oxymetholone, 7 - 50 μg/mL for 19-nor androstenedione, 19-nortestosterone, and oxandrolone, and 3 - 20 μg/mL for methyl testosterone, clostebol, stanozolol, trenbolone enanthate, testosterone enanthate, and nandrolone decanoate. The developed method is validated by acceptable precision (CV < 20%) and good accuracy (94% < R < 114%). The value of limit of detection (LOD) for all derivatives was in the range of 0.02 - 0.16 μg/spot (20-160 μg/g of supplement), while limit of quantitation (LOQ) was found to be in the range of 0.06 - 0.5 μg/spot (60 - 500 μg/g of supplement). Fifty sports supplement samples as real sample were collected and analyzed. None of the samples screened positive using the HPTLC method. In the present study, the fast, cheap, and simple HPTLC method could be used for the multi-residue analysis of ten anabolic androgenic steroids in sports supplements.

Investigation of sexual maturity and change in gonadosomatic index of sex riversed rainbow trout (Oncorhynchus mykiss) treated by oral 17 alpha methyl testosterone

Investigation of sexual maturity and change in gonadosomatic index of sex riversed rainbow trout (Oncorhynchus mykiss) treated by oral 17 alpha methyl testosterone

Optimization of 17α-Methyl Testosterone Dose in Artemia Nauplii and Rotifer using Enrichment Technique

Background: The present study explored the possibility of using live feed, as vector for supplementing the androgenic hormone in aquaculture seed production. Methods: The study consisted of five treatment doses of 17α-methyl testosterone namely; control (without hormone), T1 (20 mg L-1), T2 (40 mg L-1), T3 (60 mg L-1) and T4 (80 mg L-1) and each were triplicated. The doses were tested in the live feed of Artemia nauplii and rotifer by following completely randomized design. The Artemia nauplii (Artemia salina), collected by hatching the Artemia cyst and 5-8 days old rotifers, collected from mass culture unit of rotifer, were released in their respective treatment doses at 100 and 800 individuals/ml, respectively. Result: The study found significant difference in accumulation of hormone in the tissues of live feed at different time intervals. In Artemia, significantly higher amount of 17α-MT (15.33±0.09 mg L-1) was observed in 80 mg L-1 group at 24 h. In rotifer, significantly higher value of 17α-MT (17.42±0.06 mg L-1) was recorded in 60 mg L-1 group at 6 h. The level of 17α-MT in Artemia nauplii and rotifer started showing a decreasing trend in 24 h and 6 h, respectively. Overall the findings of the present study support that supplementation of hormone through live feed is possible as live feed accumulated 17α-MT in its tissue after enrichment which can be further explored for producing all-male population in a more sustainable way.

The effect of methyltestosterone (MT) on sex differentiation and growth in juvenile yellow perch (Perca flavescens).

A study was conducted to evaluate the gonad differentiation of juvenile yellow perch (YP, Perca flavencens) and determine the latest labile period related to hormone treatment. Juvenile fish were subjected to two dietary concentrations of methyltestosterone (MT; 20 and 50mg/kg feed) for 60days in three (3) age groups of 38-, 46-, and 67-days post-hatching (dph), where control group were fed with standard commercial feed. Following a 10-month on-growing period, sex phenotypes were determined by gross and histological gonad morphology. Results showed the juvenile YP responded to the exogenous hormone when it was applied at 38 dph for both 20 and 50mg/kg feed resulting in 100% males. At 46 dph, only 50mg/kg feed resulted in 100% males. Both MT-treated at 38 and 46 dph significantly differed (P < 0.01) from the expected normal population of male:female (1:1). MT-treated at 67 dph resulted in 37% and 25% intersex fish for both 20 and 50mg/kg feed dosage groups, respectively. MT-treated at 38 and 46 dph promoted growth and showed significantly heavier mean body weight (P < 0.05) compared to control. The gonadosomatic index (GSI) of MT-treated at 38 and 46 dph was significantly lower than that in control. This study provides the first evidence that juvenile YP can be successfully masculinized when the treatment is initiated at the age of up to 46 dph. The result is important for sex control in aquaculture.

Suitable Temperature, Stocking Density and Feeding Rate for Optimal Growth of Sex Reversed Fry of Nile Tilapia &amp;lt;i&amp;gt;Oreochromis niloticus&amp;lt;/i&amp;gt; (Senegal River Strain)

Determining the suitable fish farming conditions for optimal growth is necessary for aquaculture production, but it is not very obvious because it requires a good understanding of species biology. Thus, this study aims to evaluate the effects of different temperature regimes, stocking densities, and feeding rates on the growth of Nile tilapia, Oreochromis niloticus fingerlings that have been sex-reversed with 17α methyl testosterone. Three independent experiments were performed (with replicates) at the IRD Bel-Air fish farm (Dakar, Senegal) on 27-day-old fry maintained in six 25 L tanks with a batch of 100 individuals each. These fry were subjected to three different temperatures (26˚C, 28˚C, 30˚C; kept constant with thermostats), stocking densities (5, 10 and 15 ind/l) and feeding rates (5%, 10% and 15% of biomass; distributed three times a day). For the temperature and density treatments, fry was fed a pelleted feed containing 38% protein, distributed by hand at 10% of their total biomass, readjusted after each measurement. Growth performance (total weight, weight gain and daily weight gain), physicochemical parameters (temperature, oxygen, nitrite and phosphorus), feed conversion ratio (FCR) and survival rate (SR) were regularly monitored (weekly) during the experimental period. For the heat treatment, the results did not show an apparent relationship between growth performance and nitrite, phosphorus or dissolved oxygen (DO) contents. In contrast, there was a significant correlation between temperature and growth rates, with the best growth being obtained at 30˚C compared to 28˚C and 26˚C. Similarly, growth rates were correlated with stocking density and feeding rate but not with oxygen, temperature, nitrite or phosphorus levels. The best growth rates were observed at the lowest density (5 ind/l) and for the highest feeding rate (15% of biomass), which coincides with the best FCR and survival rates. Thus, 30˚C, 5 ind/l and 15% of biomass appeared to be the most favorable temperature, stocking density and feeding rate for optimal growth of Nile tilapia fry after inversion. The application of these results in the culture systems will allow to reach a good production of O. niloticus and thus to contribute to sustainable development of fish culture in Senegal.

Use of Dietary Phytochemicals as control for Excessive Breeding in Nile Tilapia (Oreochromis niloticus): A review

Human population has continued to increase unabatedly with its attendant demands on food in order to ease the difficulties of malnutrition and starvation. This continuous rise in population has clearly indicated that the conventional forms of livestock production and captured fisheries will not be sufficient to solve the problem of high protein demands. Aquaculture remains the best option that can bridge the wide gap between human protein demands and domestic production through the culture of fish species like Nile Tilapia (Oreochromis niloticus). Oreochromis niloticus is one of the most cultured finfish, due to its acceptability as food, fast growth, availability for farmers, ability to breed in captivity, resistance to diseases and harsh environmental conditions. Despite all these outstanding characteristics, there is still high level of apathy in commercial production of Nile Tilapia, due to its precocious maturity and uncontrolled breeding, which results in overpopulation of ponds, stunted growth and low commercial value. To mitigate this challenge, the use of synthetic hormones such as 17α-methyl testosterone has been developed to masculinize female tilapia present in a pond, thereby allowing the production of marketable sized fish since the male grows faster than the female. Though, the use of synthetic hormones has helped in some ways, but the negative effects have necessitated farmers to seek alternatives that are environmental friendly and safe for consumers. Dietary phytochemicals have been established to be good alternatives and their use is now gaining global acceptance. Dietary phytochemicals are bioactive compounds commonly found in plant-based diets such as fruits, vegetables, grains and teas. Dietary phytochemicals when administered to newly hatched tilapia species, influences the undifferentiated gonadal tissue of generic females to develop testicular tissue, thus functioning reproductively as males. Some of these phytochemicals such as Flavonoids, Saponins, Phenolics and Alkaloids are found in plants like Carica papaya seeds, Azadirachta indica, and Mucuna pruriens. The usefulness of these phytochemicals is based on their ability to influence sex reversal in Oreochromis niloticus, cost effect, easily accessible especially by small scale fish farmers, simple to apply, and being safe for both human and the environment since they are more biodegradable than synthetic hormones.