To carry out this study, we used as biological material the species O. niloticus, a strain from the Senegal River valley (NAA Richard TOLL). The experiments began with the recovery of larvae (average weight between 0.01 and 0.02 g) from broodstock (body mass between 100 and 200 g) well adapted to life in captivity at the agriculture community estate of fish farm. These larvae were subdivided into 12 batches (12 aboveground tanks of 1 m³ each) of 150 individuals each +−5%. We used two (02) 10 m³ concrete tanks for breeding, with a ratio of 1 male to 3 females. For the incubation equipment, we used: six (06) bottles of zoug for incubating the eggs; six (06) trays for resorbing the yolk sac; six (06) happas for recovering the larvae and one (01) 12 kV submersible pump for supplying water to the incubation table. To formulate the hormone feed, we used 60 mg/kg of 17-alpha-methyl-testosterone powder; 95% alcohol (Ethanol); very fine industrial feed containing 40% protein and glassware (test tubes, spoons, trays, bottles; gloves, gown, boots, bags, cloth, mask). For the formulation of the feed containing the Garcinia kola powder: Garcinia kola (bitter kola) from the Republic of Guinea; 95% alcohol (ethanol) and very fine industrial feed containing

Picture 1. Itato DAC fish farm (Sarr, 2022).

40% protein. And equipment to measure physical and chemical parameters (thermometer: to measure the temperature of the water, oximeter (DO9100): to measure the dissolved oxygen in the water, pH-meter: to measure the hydrogen potential of the water, GPS: to locate the study area, scales: to measure weights).

The physical and chemical parameters of the water, such as temperature, pH and dissolved oxygen, are measured every day using a thermometer, a pH meter and an oximeter. Table 1 shows the physico-chemical parameters of the different rearing systems.

A sample of 25% of the population was taken on a weekly basis to check the biomass and readjust the feed ration for the week. After 28 days of rearing, all the fish were sampled and counted, and 20 individuals chosen at random from each tank were measured for length and individual weight. On day 75, corresponding to the end of pre-pregnancy, all the fish were captured and sexed manually. Sex was confirmed by direct observation of the genital papillae of each specimen. Various zootechnical parameters such as sex ratio, survival rate, average weight gain, specific growth rate, nutrient quotient and mortality rate were calculated. Table 2 shows the calculation of zootechnical performance parameters.

Data on sexual inversion rates are listed in Table 3. The percentages of males in the positive control batch and the batch treated with 20 g of G. kola were significantly (p < 0.0001) higher than those in the other batches. On the other hand, that of the negative control batch was significantly lower than that of the batches treated with the food supplement (p < 0.017). For the batches treated with G. kola powder, the best male rate was obtained in the batch treated with 20 g of G. kola (94.03% - 93.06%). The greater quantity of G. kola extract, the less the individuals consumed the food because of its bitter taste (high tannin content). The comparison of the two batches (positive control and 20 g of G. kola) was significantly better than those of the other batches (negative control and 10, 30 and 40 g of G. kola). The positive control batch had 97.03% and 98.09% males respectively and the batch treated with 20 g of G. kola had 94.03% and 93.26% males respectively. The negative control batch had 49.22% and 53.02% males respectively and the batch treated with 10 g of G. kola had 80.01% and 75.72% males respectively. Table 3 shows the distribution of sexual inversion rates by basin and Figure 1, Figure 2 show sexual inversion rates as a function of treatment.

Weight growth data are shown in Table 4. The treatment duration was set at 28 days. The observed weight growth performances were significantly better (p < 0.009; Friedman’s k paired samples comparison test) (Table 4) in the batches fed the positive control diet and 30 g of G. kola extract, followed by those fed diets containing 10 and 20 g of G. kola extract. On the other hand, the negative controls were closer to those containing 40 g of G. kola extract. On the 28th day of treatment, a sample of 50 individuals was taken from each tank and the mean final weights of the populations treated with 10, 20, 30 and 40 g of G. kola extract reached 0.532 - 0.588 g, 0.672 - 0.644 g, 0.868 - 0.896 g and 0.476 - 0.504 g respectively. Those of the negative and positive control populations reached

0.308 - 0.308 g and 0.896 - 0.980 g respectively. The growth performance of the inverted fry was very good. These results confirm the study according to which the incorporation of plant extracts and hormone in the diet of tilapia O. niloticus significantly improves the growth performance of fry compared to the simple commercial feed commonly used in fish farming [1] . Figure 3 shows the dynamics of tilapia weight growth according to the feed ration.

On day 28, the Tilapia had the same weight gain when fed the positive control as when fed a ration supplemented with 30 g of Garcinia kola. In fact, any increase of 10 g in the amount of Garcinia kola produced a significant weight gain up to 30 g (p ≤ 0.023). Beyond this quantity, the increase in the proportion of bitter cola had a depressive effect on the weight growth of the Tilapia. Figure 4 shows the weight gain of Tilapia on day 28 according to the feed ration.

Survival rates were higher when Tilapia were fed a diet enriched with Garcinia cola powder compared to survival rates obtained with fish fed Positive Control and Negative Control (p ≤ 0.039). Although the survival rate was not significantly different in Tilapia supplemented with Garcinia, the excess would appear to lead to Tilapia mortality. Thus, on day 28, the mortality rate recorded for the survival rates was close to 95% in the batch of fish treated with fish given 20 g of G. kola. On the other hand, high mortality was recorded in batches treated with the hormone 17alpha methytestosterone (MT) compared with the negative control (p ≤ 0.0002). Mortality was greater during the 28 days of hormone inversion than during fry rearing. Figure 5 shows the survival rate of fish populations in different tanks.

Populations of fish treated with the hormone 17-α-methyl testosterone and 20 g of G. kola extract recorded the highest proportions of males. According to [10] , the hormone 17-α-methyl testosterone has anabolic effects. Thus, androgen-treated Tilapia fry generally grow faster than untreated individuals, probably due to increased appetite, improved food utilization and protein synthesis. However, there are certain limitations to the techniques involved, such as: contamination of broodstock, the vigilance required in the selection and maintenance of broodstock, the requirements for a high level of control and consumer acceptance of hormonal sex-reversal fish may be limited even in countries where hormonal applications to food fish are an accepted practice. On the other hand, G. kola extracts incorporated in different fish diets, favors the increase of male proportions [1] . The results of the present study confirm the studies of several

authors with a reversal rate of over 95% males. The presence of steroids in G. kola seeds could be the basis of their androgenic activity. According to [11] , various pathways are associated with functional mechanisms of phytochemicals causing both masculinization and feminization at different concentrations.

The present study shows that the presence of plant extracts (Garcinia kola) in the various fish diets improves their growth. The plant extracts did not have a negative influence on growth performance except for the batch of populations treated with 40 g of G. kola extracts. In fact, the various studies have shown that the use of medicinal plants as feed supplements gives interesting zootechnical results, more specifically Garcinia kola (Gultiferae). However, the results also show poor growth in populations treated with a high concentration of Garcinia kola (40 g). G. kola is a plant rich in tannins. The tannins derived from this plant are bitter and form a high polyphenolic complex with proteins, making it unavailable in the diet. Tannin can reduce protein quality by lowering digestibility and palatability. It also inhibits the activities of digestive enzymes. The presence of a high proportion of tannins in diets enriched with higher concentrations of root or seed powder could lead to poor food consumption by fish, resulting in stunted growth. G. kola is a medicinal plant commonly used in traditional medicine, rich in flavonoids, saponins, steroids, tannins and terpenoids [12] . These bioactive principles are thought to influence various parameters, including appetite stimulation and fish growth in aquaculture. In addition, the growth of inverted fry is very impressive. [13] Compared the rearing performance of different strains of Oreochromis niloticus and found that across all strains, TM treatment of the fish resulted in a final size 10.7% larger than untreated fish. This supports the idea that treated fish populations grow much faster than those fed simple feed and is consistent with the results of our present study.

In the course of this study, we recorded good survival rates for batches fed with G. kola plant extracts and also for batches treated with simple feed. On the other hand, the populations of fish treated with methytestosterone hormone were low. [12] Specifies that the mortality rate is higher in the early stages of development, during hormone treatments, and tends to stabilize in the later stages of ontogeny. In other words, concentrations of plant extracts did not have a negative influence on larval survival rates. Similar conclusions were reached by [1] . Similarly, the survival rates observed would indicate that these fry value the feed well without affecting their survival.