A total of two hundred samples of “Garba” and rice eggplant sauce were randomly purchased from vendors and restaurant owners located in Abobo, Cocody and Yopougon, three communes in the Autonomous District of Abidjan. Sampling was carried out every day over a period of ten days. The samples were collected in their various sales packages (Photograph 1), placed in coolers and transported to the laboratory of the Biological Resource Centers (CeReB) of the Institut Pasteur de Côte d’Ivoire (IPCI) for biochemical analysis.

Photograph 1. Garba and rice eggplant sauce bought from the shopkeepers.

In the laboratory, the dishes were weighed using a precision balance. Once weighed, these dishes were removed from their packaging and boned (remove the fish bones). Then, all the dishes from each commune were put together, crushed and homogenized to make a single dish of Garba and rice with eggplant sauce in order to compensate for certain variabilities due to the method of cooking and the use of ingredients. These dishes were reweighed and freeze-dried to obtain the different flours for the different analyses (Figure 1).

Wistar rats (Rattusnorvegicus) of both sexes (n twenty; Biology and Health animal house of the UFR BIOSCIENCES of the University Félix Houphouët-Boigny Abidjan, Côte d’Ivoire) weighed between 50 and 60 g on average and aged 45 ± 5 days were individually housed in metabolic cages equipped with urine and fecal separators, in temperature-controlled rooms (25˚C to 26˚C), with 12 hours of daylight and a 12-hour period of darkness, and the humidity percentage was 70% to 80%, with free access to food during the entire experimental period. Rats were fed a formulated control diet (RTP) rich in herring fish (Clupeaharengus) protein with the following composition: 65% Corn starch (Merck), 16% protein, 8% mineral blend formula AIN 93M [13] and vitamin blend formula AIN 76A [14], 3% Agar-agar cellulose and 8% palm vegetable oil, a control diet without protein (RSP) isocaloric consisting of all the ingredients mentioned except protein, one diet composed of tuna “Garba” dishes (Gab) and one dish composed of rice eggplant sauce (Risa) all freeze-dried and submitted to the rats for fifteen days.

Proximal analyses were performed in triplicate on the samples. This analysis included the following: moisture, total lipids, crude protein, carbohydrates and ash. Moisture content was estimated by drying the samples to a constant weight at 105˚C using the oven method [15]. Lipid determination was performed by the Soxhlet extraction method. The ash content was determined by igniting the sample at 550˚C in a muffle for a period of 5 - 6 hours until the sample was completely free of carbon particles while total nitrogen was determined by the Kjeldahl method as described by Vlieg [16] and a factor of 6.25 was used to convert the total nitrogen to crude protein content of the samples. The total carbohydrate content was calculated by using the equation: 100 − (%moisture + %proteins + %lipids + %ash) [17]. Mineral analyses were performed according to the method [18]. The contents of minerals, including Calcium, Sodium, Potassium, Phosphorus and Iron were analyzed using an atomic absorption spectrophotometer (model SHIMADZUS 5, type A.A-6200).

The contents of water-soluble vitamins were described by Rougereau [19] and determined by high performance liquid chromatography (HPLC) type SHIMADZU SPD 20A equipped with a UV detector (PAD) at 325 nm and C18 ODS column (250 × 4.6 of Cluzeau de France).

The extraction of some amino acids was performed according to the modified method [20]. 1 g of delipidated sample powder prepared in 10 mL of 6N HCl was dried at 110˚C in an oven for 24 h and then under nitrogen flow. The dry residue was taken up in 10 mL of 0.2 N sodium citrate at pH 2.3. The homogenized mixture was centrifuged at 3000 rpm for 25 min at 0˚C. The collected supernatant was filtered through a Whatman #4 paper and then through a 0.45 µm diameter millipore filter (Sartorius AG, Goëttingen, Germany). The treated supernatant was stored at −20˚C before analysis. The amino acid composition of the samples was determined after hydrolysis with 6 M HCl with 1% phenol at 150˚C for 60 minutes. The solvent used was a solution of sodium acetate (45 mM; pH 5.9) and a mixture of 30% sodium acetate (105 mM, pH 4.6) and 70% acetonitrile. The detector was selected at 280 nm.

The extraction of some amino acids was performed according to the modified method [20]. 1 g of delipidated sample powder prepared in 10 mL of 6N HCl was dried at 110˚C in an oven for 24 h and then under nitrogen flow. The dry residue was taken up in 10 mL of 0.2 N sodium citrate at pH 2.3. The homogenized mixture was centrifuged at 3000 rpm for 25 min at 0˚C. The collected supernatant was filtered through a Whatman #4 paper and then through a 0.45 µm diameter millipore filter (Sartorius AG, Goëttingen, Germany). The treated supernatant was stored at −20˚C before analysis. The amino acid composition of the samples was determined after hydrolysis with 6 M HCl with 1% phenol at 150˚C for 60 minutes. The solvent used was a solution of sodium acetate (45 mM; pH 5.9) and a mixture of 30% sodium acetate (105 mM, pH 4.6) and 70% acetonitrile. The detector was selected at 280 nm.

1) Variation in body length (BL) and abdominal circumference (AC)

The variation in the dimensions of different parts of the body is a parameter that attests to the nutritional efficiency of different diets. Thus, body length (LB) and abdominal circumference (AC) were assessed using a non-stretchable plastic tape measure with an accuracy of 0.1 cm according to the method described by Silva [21].

For the length measurement, the lying young rat is held so that it does not move. Then the tape measure is placed so that it touches the nose at the tail and the measurement is taken. For the determination of AC, the rat was elongated and the measurement was taken by the hip circumference. The growth, reflected by the change in body length (CL) and abdominal circumference (AC) is obtained respectively by the difference between the final length and the initial length. It is expressed in cm.

L B = L e n g t h ( f i n a l − i n i t i a l ) (1)

C A = C i r c u m f e r e n c e ( f i n a l − i n i t i a l ) (2)

With:

LB: Body length;

AC: Abdominal Circumference.

2) Determination of Lee’s Index (LI), Adipocyte Index (AI) and Body Mass Index (BMI)

The following anthropometric parameters BMI, Adipocyte Index and Lee’s Index were determined according to the calculation method of [22] [23] Thus, obesity was defined by a BMI greater than 0.68 g/cm².

B M I = B W / B L (1)

A I ( % ) = T B F / F B W (2)

L I = P C 3 / B L (3)

With:

BW: Body weight;

BL: Body length;

P C 3 : Cubic root of body weight;

TBF: Total body fat;

FBW: Final body weigh.

The batches of rats fed the control diets (RSP, RTH) showed mean values in Body Length as a function of the initial day (D1) to the final day (D15) respectively from (14.17 ± 0.31 cm to 15.33 ± 0.95 cm and 14.33 ± 0.21 cm to 20.33 ± 0.42 cm and those of the batches of rats fed the test diets gave values from 14.5 ± 0.22 cm to 20 ± 0.37 cm; 14.5 ± 0.5 cm to 21 ± 0.00 cm for the Gab and Risa diets, respectively. The Risa diet observed the value in Body Length from 14.5 ± 0.5 cm to 21 ± 0.00 cm. Statistical analysis showed a significant difference (p < 0.05) between the body lengths of different batches of rats fed the different diets (Figure 2).

Analysis of abdominal circumference recorded mean values of 9.2 ± 0.2 cm to 5.4 ± 0.24 cm; 9.00 ± 0.45 cm to 12.6 ± 0.24 cm for rats fed the RSP and RTH control diets respectively. For the Gab and Risa test diets, respectively, the analysis recorded values of (8.6 ± 0.51 cm to 11.00 ± 0.45 cm and 10.00 ± 0.00 cm to 12.6 ± 0.24 cm). However, the value of abdominal circumference of rats fed the RTH diet was identical to that of rats fed the Risa diet. However, statistical analysis indicated a significant difference (p < 0.05) between all values of abdominal circumference of batches of rats fed the different diets (Figure 3).

The BMI values of the rats ranged from 0.26 ± 0.01 to 0.32 ± 0.01 g/cm². The control batches observed values of 0.26 ± 0.01 g/cm² and 0.32 ± 0.01 g/cm² respectively for the RSP, RTH diets. For the experimental diets (Gab and Risa), the BMI values were 0.27 ± 0.01 g/cm² and 0.31 ± 0.01 g/cm² respectively. However, the RTH diet noted the high value in BMI of (0.32 ± 0.01 g/cm². However, the statistical analysis presented a significant difference (p < 0.05) between the BMI values of the rats fed with the different diets (Table 5).

The Lee index of rats fed with the respective diets (RSP, RTH, Gab and Risa) recorded values of (0.26 ± 0.00 cm; 0.26 ± 0.00 cm; 0.25 ± 0.01 cm and 0.26 ± 0.00 cm). On the other hand, batches of rats fed the different diets showed essentially identical values. Statistical analysis revealed no significant difference (p > 0.05) between the Lee index of all batches of rats fed the different diets (Table 5).

Adipocyte index levels are presented in Table 5. The analysis revealed AI contents ranging from 0.92% ± 0.02% to 2.45% ± 0.68%. For the control batches (RSP and RTH), the AI contents were 0.92% ± 0.02% and 2.45% ± 0.25%, respectively. For the batches of rats fed the Gab and Risa diets, the analysis recorded levels of 1.67% ± 0.25% and 1.96% ± 0.21% respectively. On the other hand, the diet (RTH) recorded the high AI value (2.45% ± 0.25%). There is no significant difference (p > 0.05) between the AI contents of all batches of rats fed with the different diets.