Performance of selective media for E. coli O157, using non-sorbitol fermenting strains and physiological characters of shiga-toxin producing species isolated in Côte d'Ivoire

Performance of three selective media, tmperature and pH effects on growth of E. coli O157:H7 isolated in Ivory Coast were investigated. Thirty-eight (38) non-sorbitol fermenting E. coli were characterized by serotyping, detection of shiga-toxin gene (PCR) and plating on SMAC, VRMUG and BCMtm media for Performance evaluation. Temperature and pH effects on E. coli O157:H7 were measured in varied culture conditions. All culture media were sensitive (100%) for the growth of E. coli O157. Their specificities were 97.3, 94.7 and 50.7% respectively for VRMUG, BCMtm and SMAC media. Predictive value for VR-MUG medium was 66%, whereas that for SMAC medium was only 5.4%. Serotype O157:H7 E. coli population grew slightly at 42 °C and didn’t grow under acid conditions (pH 4.5, 3.5). The performance of the culture media evaluatedand the physiological data obtained for E. coli O157:H7 during this study would contribute to improve both isolation and identification methods of the pathovars.© 2010 International Formulae Group. All rights reserved.Keywords: E. coli O157H7, performance, culture medium, shiga-toxin, pH, temperatur

Comparative study of physicochemical and thermal properties of the seed oils of three cucurbit species

Three indigenous cucurbit seeds from Ivory Coast namely Cucumeropsis mannii Naudin, Citrullus lanatus var. Citroides (Thrumb.) Matsum & Nakai and Cucumis melo var. Agrestis were investigated for the physicochemical properties. Thermal properties of their crude oils extracted by a cold solvent method were also tested. Physicochemical characterization of the seeds showed that they are important sources of proteins, lipids, carbohydrates and mineral elements. C. lanatus seeds had the highest lipid content (46.40%) followed by C. melo seeds (36.50%) and C. mannii seeds (35.70%) on dry weigh bases. Most of the index values and chemical characteristics of extracted seed oils are not significantly different, except for the peroxide value and the color parameters of C. mannii. Linoleic acid, whose values ranged from 54.84% to 70.76%, was the major fatty acid out of all seed oil species. The thermal properties revealed that C. melo seed oil had low transition temperatures followed by C. lanatus seed oil and C. mannii seed oil depending on their fatty acid compositions. These results suggest that these thermal properties could be used in the industrial fractionation and the cucurbit seed oils may be used as edible oils due to their similarity to the commonly used edible oils

Effect of non-use of antibiotics on the zootechnical performance of cobb 500 broiler chickens at the Diallo farm in the commune of Korhogo, northern Côte d'Ivoire.

This study was conducted at the Diallo farm in the commune of Korhogo, precisely in the new district. The general objective of this study was to evaluate the effect of not using antibiotics on the zootechnical performance of Cobb 500 broiler chickens. The experimental device consisted of constituting 2 batches of 50 broiler chickens. Batch 1, which is the control batch, did not receive antibiotics after the start until the end of the experiment. Batch 2 received antibiotics for six (6) weeks. The results showed that the broilers of batch 1 obtained the best zootechnical performance. After 42 days of breeding, the chickens of this batch consumed 6300 ml of water and 3150 g of food per bird. They obtained an average weight of 2230g against 1950g for batch 2. Similarly, they obtained a low mortality rate (8%) and a better carcass yield (75.33%). Ultimately, breeders would benefit from avoiding antibiotics for better zootechnical performance in broilers and to preserve human health

Contamination des fèves de cacao par les hydrocarbures aromatiques polycycliques (HAP) en Côte d’Ivoire

This study aim is to evaluate the contamination of cocoa beans by polycyclic aromatic hydrocarbons (PAH) in three cocoa-producing regions of Côte d’Ivoire (Divo, Gagnoa and Soubré). A total of 30 samples of cocoa beans were taken from the three major cocoa production regions. These samples were transported to the laboratory for analysis using High-Performance Liquid Chromatography (HPLC). The results of this study showed that some samples were contaminated with PAHs with the highest levels found in samples from the town of Soubré. The average BaP contents vary from 0.001 to 0.030 µg/kg, much lower than the maximum residue limit which is 2 µg/kg. For the BaA molecules, no traces were detected in the different samples analyzed. In general, the contaminations observed in the three localities could be due to poor agricultural practices. Key words: PAH, residues, cocoa beans, contaminationCette étude se propose d’évaluer la contamination des fèves de cacao par les hydrocarbures aromatiques polycycliques dans trois régions productrices de cacao en Côte d’Ivoire (Divo, Gagnoa et Soubré). Au total, 30 échantillons de fèves de cacao ont été prélevés dans les trois grandes régions de production cacaoyère. Ces échantillons ont été transportés au laboratoire pour analyse à l’aide d’une chaîne de Chromatographie Liquide à Haute Performance (HPLC). Les résultats de cette étude ont montré que certains échantillons ont été contaminés par les HAP. Les teneurs les plus élevées se retrouvent dans les échantillons de la localité de Soubré. Ces teneurs moyennes en BaP varient de 0,001 à 0,030 µg/kg, très inférieures à la limite maximale de résidus qui est de 2 µg/kg. Pour les molecules de BaA, aucune trace n’a été détectée dans les différents échantillons analysés. D’une manière générale, les contaminations observées dans les trois localités pourraient être dues à de mauvaises pratiques agricoles. Mots clés: HAP, résidus, fèves de cacao, contaminatio

Effect of cooking and extraction method on oleaginous cucurbit seed oils quality

In sub-Saharan Africa, Lagenaria siceraria seeds are cooked before consumption. Cooking seed may alter their chemical composition, leading to changes in their health benefits. Thus, this study aimed at determining the effect of cooking of L. siceraria seeds on their edible oil quality. Heat treatments were performed as roasted (100 and 125 \ub0C) and boiled (10, 35, 60 and 90 min). Then oils were extracted with petroleum ether solvent and hot-water flotation process. Peroxide and acid index, and fatty acids composition were evaluated. With the hot-water flotation process, roasting and boiling had no significant effect on acid index and fatty acids composition. However, peroxide values varied from 1.1 to 2.9 meqO2 kg-1 oil. The highest peroxides values were revealed at 90 and 60 min, respectively, in seeds roasted at 100 and 125 \ub0C. With solvent extraction, roasting and boiling affected only peroxide values and fatty acids composition. The highest peroxide values were reached after 10 min of ebullition of roasted seeds, both at 100 and 125\ub0C. Saturated and polyunsaturated fatty acid contents increased after 10 min of boiling of seeds roasted at 100 and 125\ub0C; then decreased to reach the initial content. But, the monounsaturated fatty acids content decreased after 10 min of boiling, and then increased to reach the initial content. The highest values of peroxides and polyunsaturated fatty acids contents were observed with solvent extraction compared to hot-water flotation method. Cooking of L. siceraria seeds does not alter the quality of their oil; solvent extraction makes their oil highly unstable.En Afrique subsaharienne, les graines de Lagenaria siceraria sont consomm\ue9es cuites. La cuisson des graines peut alt\ue9rer leur composition chimique, entra\ueenant des changements quant \ue0 leurs bienfaits pour la sant\ue9. Ainsi, cette \ue9tude visait \ue0 d\ue9terminer l\u2019effet de la cuisson des graines de L. siceraria sur la qualit\ue9 de leurs huiles. Les traitements thermiques ont \ue9t\ue9 effectu\ue9s: torr\ue9faction (100 et 125 \ub0 C) et \ue9bullition (10, 35, 60 et 90 min). Les huiles ont, ensuite, \ue9t\ue9 extraites avec l\u2019\ue9ther de p\ue9trole et par un proc\ue9d\ue9 de flottation \ue0 l\u2019eau chaude. L\u2019indice de peroxyde et d\u2019acide ainsi que la composition en acides gras ont \ue9t\ue9 \ue9valu\ue9s. Avec le proc\ue9d\ue9 de flottation \ue0 l\u2019eau chaude, la torr\ue9faction et l\u2019\ue9bullition n\u2019ont eu aucun effet sur l\u2019indice d\u2019acide et la composition en acides gras. Cependant, les valeurs de peroxyde variaient de 1,1 \ue0 2,9 m\ue9qO2.kg d\u2019huile. Les valeurs les plus \ue9lev\ue9es de peroxydes ont \ue9t\ue9 r\ue9v\ue9l\ue9es \ue0 90 et 60 min respectivement dans les graines torr\ue9fi\ue9es \ue0 100 et 125 \ub0 C. Avec l\u2019extraction par solvant, la torr\ue9faction et l\u2019\ue9bullition n\u2019ont affect\ue9 que les valeurs de peroxyde et la composition en acides gras. Les valeurs de peroxyde les plus \ue9lev\ue9es ont \ue9t\ue9 atteintes apr\ue8s 10 min d\u2019\ue9bullition des graines grill\ue9es \ue0 100 et \ue0 125 \ub0C. Les teneurs en acides gras satur\ue9s et polyinsatur\ue9s ont augment\ue9 apr\ue8s 10 min d\u2019\ue9bullition des graines torr\ue9fi\ue9es \ue0 100 et 125 \ub0C puis ont diminu\ue9 pour atteindre leurs teneurs initiales lorsque le temps d\u2019\ue9bullition a augment\ue9. Mais, la teneur en acides gras monoinsatur\ue9s a diminu\ue9 apr\ue8s 10 minutes d\u2019\ue9bullition, puis a augment\ue9 pour atteindre la teneur initiale. Les valeurs les plus \ue9lev\ue9es des teneurs en peroxydes et en acides gras polyinsatur\ue9s ont \ue9t\ue9 observ\ue9es avec l\u2019extraction par le solvant compar\ue9 \ue0 la m\ue9thode de flottation \ue0 l\u2019eau chaude. Cuire les graines de L. siceraria n\u2019alt\ue8re pas la qualit\ue9 de leur huile\ua0; l\u2019extraction par le solvant rend leur huile hautement instable

GENETIC EVALUATION OF SEED TRAITS FROM INTRASPECIFIC CROSSING OF GENETICALLY DISTINCT WATERMELON VARIETIES

Citrullus lanatus (Thunb.) Matsumura and Nakai (Cucurbitaceae) is an important cucurbit crop worldwide. Global production of watermelon is about 90 million metric tonnes per annum, making it among the top five most consumed fresh fruits. The objective of this study was to evaluate seed variability in different segregating populations, and determine heritability of traits of watermelon. Interspecific crosses were made between two cultivars of C. lanatus (Bebu and Wl\ueawl\uea Small Seeds (WSS) were performed at Research Station of Nangui Abrogoua University in Abidjan, C\uf4te d\u2019Ivoire. There was wide variability between parental, F1, BC1 (first generation of back-crossing) and F2 seeds. Seeds of all hybrid populations were intermediate versus those of the parents. Also, crossing did not affect F1 and F2 seed characters, but affected those of BC1 because of maternal effects. Thus, back-crossing on Bebu cultivar produced seeds which looked like those of Bebu; while back-crossing on WSS cultivar produced seeds similar to those of WSS. Principal Component Analysis (PCA) and individuals repartitioning revealed that Bebu and WSS cultivars were genetically distinct and showed three main groups: two groups from each parental line and one from a recombinant line (hybrids). F2 population had a wide individual\u2019s dispersion, and contained seeds of all other populations. High heritability was observed for all evaluated characters.Citrullus lanatus (Thunb.) Matsumara et Nakai (Cucurbitac\ue9e) est une importante cucurbite dans le monde entier. La production annuelle globale est d\u2019environ 90 million de tonne, ce qui place cette culture parmi les cinq fruits les plus consomm\ue9s crus. L\u2019objectif de cette \ue9tude est d\u2019\ue9valuer la variabilit\ue9 des graines de diff\ue9rentes populations en s\ue9gr\ue9gation et de d\ue9terminer l\u2019h\ue9ritabilit\ue9 des caract\ue8res chez l\u2019esp\ue8ce Citrullus lanatus. Pour cela, un croisement intersp\ue9cifique entre deux cultivars de Citrullus lanatus (Bebu et Wl\ueawl\uea \ue0 petites graines (WSS)) a \ue9t\ue9 effectu\ue9 \ue0 la station de recherche de l\u2019Universit\ue9 Nangui Abrogoua d\u2019Abidjan (C\uf4te d\u2019Ivoire). Il existe une variabilit\ue9 importante entre les graines parentales, F1, BC1 (premi\ue8re g\ue9n\ue9ration de back-cross) et F2. Les graines de toutes les populations hybrides sont interm\ue9diaires \ue0 celles des parents. Aussi, le sens de croisement n\u2019affecte pas les caract\ue8res des graines F1 et F2 mais affecte ceux des graines BC1 \ue0 cause de l\u2019effet maternel. Ainsi, un backcross effectu\ue9 sur le cultivar Bebu produit des graines semblables aux graines de Bebu tandis qu\u2019un backcross effectu\ue9 sur le cultivar WSS produit des graines semblables aux graines de WSS. L\u2019Analyse en Composantes Principales et la r\ue9partition des individus dans le plan permettent d\u2019observer que les cultivars Bebu et WSS sont g\ue9n\ue9tiquement distincts et montrent trois principaux groupes\ua0: deux groupes de chaque type parental et un type recombinant (hybride). La population F2 a une large dispersion et se compose des graines de toutes les autres populations. Une forte h\ue9ritabilit\ue9 a \ue9t\ue9 observ\ue9e pour tous les caract\ue8res \ue9valu\ue9s. En somme, la variabilit\ue9 des graines observ\ue9es dans les populations en s\ue9gr\ue9gation chez C. lanatus pourrait \ueatre due \ue0 des effets g\ue9n\ue9tique

Higher order WKB corrections to black hole entropy in brick wall formalism

We calculate the statistical entropy of a quantum field with an arbitrary spin propagating on the spherical symmetric black hole background by using the brick wall formalism at higher orders in the WKB approximation. For general spins, we find that the correction to the standard Bekenstein-Hawking entropy depends logarithmically on the area of the horizon. Furthermore, we apply this analysis to the Schwarzschild and Schwarzschild-AdS black holes and discuss our results.Comment: 21 pages, published versio