The study took place from April 21 to July 5, 2023 in the Massoma fish farm (FPM) is located in the Mbedi district in the village Bojongo, Douala 4th district between 04˚05'41'' - 04˚06'14'' of North Latitude and 09˚35'22'' - 09˚37'17'' Longitude East, in the Wouri Department, Littoral Region.

The study lasted 75 days, with the aim of evaluating the monitoring rate, growth parameters as well as the cost of production of the feed. 450 Clarias gariepinus fry with an average weight of 7 ± 1.5 g were taken from the fry production of the Mas-soma farm.

The fruits of Tetrapleura tetraptera were purchased from the local market, crushed, sifted, then the powder was incorporated into the food at different rates.

Fifteen happas with a mesh diameter of 0.2 mm and a dimension of 0.7 m * 0.7 m * 1 m were previously sewn and installed in a 24 m² concrete tank. 450 fry were distributed in triplicates in 5 treatments of 75 individuals with an average weight of 7 ± 1.5 g following a completely randomized design (3 repetitions × 5 treatments). Each replicate contained 25 fry and each treatment 75 fry. Five rations were formulated and distributed randomly.

Every two weeks (15 days), control fishing was carried out and the weight and height of each individual was taken. The physicochemical parameters of the water including pH and temperature were recorded every day throughout the study period.

For this study, the ingredients for the production of our food were purchased in a local feed mill. A food with 38% protein was formulated. Once the purchasing operation was completed, the ingredients were weighed according to the previously established formula, then ground to obtain a fine powder, after grinding they were mixed and extruded. Then the feed from the excavator was dried in the sun in order to eliminate impurities and increase the feed conditioning time. Once dry, it was packaged in a hermetically sealed bag and stored in the store. Five rations were formulated. The control rations (T₀₊) were the imported Blue crown brand feed and (T₀₋) those not containing the fruit powder of T. tetraptera and the three other rations T_0.3, T_0.4 and T_0.5 where the T. tetraptera fruit powder was supplemented at 0.3% respectively; 0.4% and 0.5% in the control ration T₀₋ (Table 1).

T₀₋: without supplement (negative control);

T₀₊: Blue crown imported feed (positive control);

T_0.3: feed supplemented with 0.3% Tetrapleura tetraptera fruit powder;

*Premix 5%; Metabolizable energy = 2078 Kcal/Kg; Crude protein = 40%; Lysine = 3.3%; Methionine = 2.40; Calcium = 8%; Phosphorus = 2.05%.

T_0.4: feed supplemented with 0.4% Tetrapleura tetraptera fruit powder;

T_0.5: feed supplemented with 0.5% Tetrapleura tetraptera fruit powder.

The study took place over a period of 75 days. Each treatment thus contained a total of 75 fry, therefore 3 happas of 25 fry each. The fish were fed three times a day at fixed times of 8 a.m., 1 p.m. and 6 p.m. at a rate of 7% of their ichthyo-biomass during the first fifteen days then at their nap until the end of the experiment. A control fishing was carried out every two weeks (after 15 days) and at the end of the fishing, the growth characteristics such as weight were measured using a balance sensitive to 0.001 g when loaded. Then with an SF-400 balance with a sensitivity of 1 g, the size (total length) of the fry was measured using graph paper. Before distribution of the different diets, the quantities proportional to the densities of the fry for each happa were calculated and weighed. These quantities of feed distributed to the fry were adjusted according to their development. A TDS/EC/PH/SALT/SG/ORP brand multi-parameter was used for taking the temperature and the JBL brand analysis kit for taking the physicochemical parameters.

➢ Survival rate (SR)

SR (%) = 100 × NF/Ni.

NF = number of fish at the end of the experiment and Ni = number of fish at the start of the experiment.

Growth characteristics:

➢ Live weight

At the start of the test and every 14 days thereafter, fish from each experimental unit were weighed. The weekly weight gain was obtained by taking the difference between 2 consecutive average weekly live weights.

➢ Average weight gain (AWG in g) = final average fish weight (FAFW in g) - initial average fish weight (IAWG in g);

➢ Average daily gain (ADG in g/day) = (FAWG-IAWG)/t With IAW = initial average weight (g), FAW = final average weight (g), t = duration of the experiment (in days);

➢ Specific growth rate (SGR in % day) = [(lnPmf − lnPmi)/rearing time (day)] × 100; Pmi = initial average weight (g), Pmf = final average weight (g);

➢ Feed conversion ratio (FCR) = Quantity of feed distributed/Body mass gain;

➢ Condition factor (K) = W × 100/LT3 with W: weight (g), LT: Total length (cm).

Data on zootechnical parameters (survival rate, average weight gain, average weight, average daily gain, specific growth rate, feed efficiency and standard length, total length and conditioning factor K) were submitted to the Analysis of variance One-way ANOVA, when there were differences, the Duncan test was applied to separate the means at the 5% significance level using SPSS 20.0 software.

Survival

The evolution of the survival rates of juveniles of Clarias gariepinus fed with feed supplemented with four sides (T. tetraptera) is illustrated in Figure 1. It appears that no significant difference (p > 0.05) was observed. However, the highest survival rate (97.33% ± 3.35%) was observed with fish fed feed supplemented with 0.4% T. tetraptera (T_0.4) followed by (90.20% ± 1.1%) of subjects fed feed without supplement (T₀₋) and the lowest survival rate (84.00% ± 1.39%) was observed in fish fed feed supplemented with 0. 5% T. tetraptera (T_0.5).

Table 2 illustrates the zootechnical characteristics of Clarias gariepinus juveniles fed feed supplemented with T. tetraptera fruit powder over the entire study period. It follows from this table that apart from the survival rate and the consumption index, all other parameters were not significantly (p > 0.05) affected by the supplementation of the feed with fruit powder of T. tetraptera.

The highest lengths (total length and standard length) (26.43 ± 1.91 cm and 23.66 ± 1.76 cm respectively) were obtained on subjects fed imported feed (T₀₊) and the least high (26.08 ± 1.93 cm and 23.33 ± 1.51 cm respectively) were observed with subjects fed feed supplemented with 0.5% T. tetraptera (T_0.5).

The evolution of the live weight of juveniles of Clarias gariepinus fed with feed supplemented with T. tetraptera fruit powder during the trial period is illustrated in Figure 2. We observe an increasing evolution of the different treatments over all the period of the study. The curve of the subjects fed the imported feed T₀₊ was above those of all the other curves with a mean value (120.93 ± 67.20 g) the highest (p = 0.946) at 75 days compared to the other treatments and that of subjects fed with feed supplemented at 0.3% (T_0.3) remained below all other curves until the end of the study.

The evolution of the daily weight gain of juveniles of Clarias gariepinus fed with feed supplemented with T. teraptera fruit powder during the duration of the experiment is illustrated in Figure 3. The curves evolve in a sawtooth pattern with a peak observed on the 60th day regardless of the treatment considered. The highest average weight gain value (2.73 ± 0.20 g) was recorded with the subjects fed the feed supplemented at 0.4%. T. tetraptera followed the subjects fed the imported feed (2.43 ± 0.10 g) and the lowest Daily weight gain (1.94 ± 0.10 g) was recorded in the subjects fed the feed without T₀ supplement at the same period.

a, b: (p < 0.05) the values bearing different letters on the same line are significantly different. T₀₊ = imported feed; T₀₋ = feed supplemented with 0% T. tetraptera fruit powder; T_0.3 = feed supplemented with 0.3% of T. tetraptera fruit powder; T_0.4 = feed supplemented with 4% T. tetraptera fruit powder; T_0.5 = feed supplemented with 0.5% T. tetraptera fruit powder of T. tetraptera; In = initial number; Fn = final number; p = probability. IN = Initial number; FN = Final number; IW = Initial weight; FI = Feed intake; SR = Survival rate; LW = Live weight; AWG = Average weight gain; ADWG = Average daily weight gain; SGR = specific growth rate; FCR = feed conversion ratio; K = condition factor; TL = total length; SL = standard length.

The observation in Figure 4 which presents the evolution of the feed conversion ratio of juveniles of Clarias gariepinus fed with food supplemented with T. tetraptera fruit powder during the period shows a sawtooth evolution for all treatments. This during the lowest mean value (1.28 ± 0.01) was recorded with the treatment fed with imported feed and the highest (1.86 ± 0.10) was recorded with the treatment supplemented with 0.3% of this spice. However, when comparing treatments having been supplemented with the powder of this spice, the treatment supplemented with 0.4% of T. tetraptera (T_0.4) made it possible to record the lowest feed conversion ratio (1.69 ± 0.02).

Figure 5, which shows the evolution of the specific growth rate of juveniles of Clarias gariepinus fed with feed supplemented with T. tetraptera fruit powder throughout the period, shows a sawtooth evolution for all treatments with a peak at the 60th day. The highest specific growth rate (3.64 ± 0.79) was observed on subjects fed imported feed (T₀₊) followed by the specific growth rate (3.37 ± 0.85) of subjects fed a the feed supplemented with 0.4% (T_0.4) of T. tetraptera and the lowest specific growth rate (3.10 ± 0.81) was obtained with the subjects fed the feed supplemented with 0.3% (T_0.5) of T. tetraptera.

The evolution of the conditioning factors k of the juveniles of Clarias gariepinus fed with feed supplemented with T. tetraptera fruit powder is shown in Figure 6. We observe a sawtooth evolution with a value of 2, 14 ± 0.5 highest observed in subjects fed feed supplemented with 0.4% T. tetraptera fruit powder (T_0.4) and a body weight index of 1.75 ± 0.39 the least high obtained in subjects fed food without supplement (T₀₋).

Survival rates recorded range from 84.44 ± 8.39 to 96.44 ± 3.5. These values are all higher (35% to 68.4%) than that obtained by [21] after 17 days of rearing in happas as well as that of [22] obtained in a metal tank (78%) based on the comparison of the sound of rice and peanut meal. Furthermore, these rates corroborate with those obtained (89% to 92%) by [23] as well as those of [24] (89 ± 5.0 to 95 ± 5.0) in their studies carried out in unfertilized and fertilized ponds. chicken droppings and pig manure on juveniles of Clarias gariepinus pond. The differences in mortality observed between these authors are due to stress, handling and overeating polluting the living environment.

The average weights are between 120.93 ± 67.20 and 81.73 ± 50.42 g. These values are comparable to those obtained (103.25 ± 5.47 and 120.07 ± 4.56) by [24] in unfertilized ponds and fertilized with pig manure respectively.

Weight gains vary from 74.73 ± 50.42 to 113.93 ± 67.20 g. These values are comparable to those obtained (96.61 ± 3.6 and 112.5 ± 2.47) by [24] in an unfertilized pond fertilized with chicken droppings. Furthermore, these results are much higher than those obtained (18.3 g) by [25] in a pond on the effects of allium sativium on the zootechnical performances of Clarias gariepinus for 6 weeks. These variations could be attributed to the quality of the food and the duration of breeding.

The average daily gains obtained from all treatments vary between 1.51 ± 0.89 g to 0.99 ± 0.67 g. These values are all lower (2.97 g; 3.6 g and 3.3 g) than those obtained by [24] in unfertilized ponds and fertilized with chicken droppings and pig manure. However, the daily gain (0.99 ± 0.67 to 1.51 ± 0.89) corroborates with those obtained (1.29 ± 0.22) by [23] . These variations between authors may be due to the conditions of breeding, the quality of the feed as well as the physico-chemical parameters of the environment.

The specific growth rates obtained are between 3.64 ± 0.79 and 3.10% ± 0.81%. These rates are all significantly higher than those with the local feed composed of 34.77% and largely much lower than those observed (11.44 ± 4.8) by [23] . However, these results corroborate with those obtained (3.6) by [22] comparing the sound of rice to peanut meal on Clarias.

The consumption index observed on all these treatments (1.28 ± 0.01; 1.76 ± 0.20; 1.86 ± 0.10; 1.69 ± 0.02; 1.74 ± 0.12) are all higher (0.81 ± 0.15) than those obtained by [23] respectively. However, all these indices are lower (1.9) than [25] . The difference in indices could be due to the growing medium, feed quality and water parameters.

The condition factors K, the coefficients obtained fluctuate from 1.75 ± 0.39 to 2.14 ± 0.15. These values are all higher (0.88 ± 0.02) than those obtained by [22] as well as those obtained (0.79 and 0.83) by [26] .