Growth of Bacillus cereus isolated from some traditional condiments under different regimens

Bacillus cereus is ubiquitous in nature and constitutes a major portion of the microbial flora of food contaminating various food samples, causing food spoilage and poisoning to the detriment of the consumers. This work was designed to study the growth characteristics of B. cereus strains isolates from traditional condiments under different growth conditions. 34 Bacillus strains were isolated from 4 local condiments iru (fermented Parkia bioglobosa seeds), ogiri (fermented Citrullus vulgaris seeds), dawadawa (fermed soy bean-Glycine max seeds) and okpehe (fermented Prosopis africana seeds) and identified as B. cereus, B. subtilis, B. pumilus and B. lichenifomis. B. cereus had the highest occurrence of 38.24%. All the B. cereus strains had their optimum and minimum growth at 37 and 4°C, respectively, while none grew at 100°C and at pH 1 and 12 when incubated for 48 h. All the B. cereus isolates had their highest growth at 10% concentration of monosodium glutamate and the lowest at 40% but their growth pattern in NaCl is strain dependent with optimum growth between 7 and 9% NaCl concentration, and as the time of exposure to ultraviolet light increased the growth decreased

Antibacterial Activities of Lactic Acid Bacteria Isolated from Selected Vegetables Grown in Nigeria: A Preliminary Report

Members of lactic acid bacteria (LAB) are known probiotics and have been reported to have antimicrobial properties. Although various researchers have documented the isolation of these bacteria from fruits and vegetables, studies on LAB associated with lettuce, cucumber and cabbage are limited and non-existing in Nigeria. This study was designed to assess lettuce, cucumber and cabbage as potential sources of LAB and investigate the actions of their bacterial cell supernatants (BCS) on some pathogenic bacteria. Using standard microbiological methods, isolated LAB were identified to species level with API 50 CH kits (Biomerieux, France). Cell free supernatants (CFS) from de Man Rogosa Sharpe (MRS) broth cultures of the LAB strains were used to challenge Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 12900 and Proteus penneri ATCC 13315 by agar well diffusion method. The control consisted of the sterile MRS broth subjected to the same growth conditions as LAB broth cultures. A total of four lactic acid bacteria were isolated as follows: Pediococcus pentosaceus 2 from cucumber, Lactobacillus cellobiosus from cabbage, Lactobacillus salivarius and Lactobacillus plantarum 1 from lettuce. Pediococcus pentosaceus 2 and L. salivarius showed inhibitory effects on all the standard strains tested while L. plantarum 1 showed no inhibitory activity against E. faecalis and E. coli. Lactobacillus cellobiosus showed inhibition against all except P. penneri. Although, the molecular characterisation and probiotic potentials of these LAB strains are being investigated in an on-going study, we presumed these vegetables are prospective sources of the bacteria in Nigeria and therefore the need to extensively investigate the vegetables and other related vegetables becomes imperative

Use of Lactic Acid Bacteria as Probiotic for Promoting Growth and Nutrient Utilization in Nile Tilapia Oreochromis Niloticus

The Lactic acid bacteria strains isolated from O. niloticus were evaluated for their probiotic activity. The strain which showed the greatest promise as probiotics was selected for growth study. Oreochromis niloticus (mean weight 18.11±0.12g) were randomly distributed to five treatments representing probiotic inclusion level at 0.25% inclusion in diets: PD1-0cfu/ml; PD2-103cfu/ml; PD3-105cfu/ml; PD4-107cfu/ml and PD5-109cfu/ml. Fish were fed twice daily at 3% body weight for 90 days. Growth, heamatological and plasma biochemical parameters of the fish were measured. Challenge test was conducted on fish fed probiotic supplemented diets using pathogenic Pseudomonas aeruginosa to assess their disease resistance to the bacterium. The growth in fish was significantly higher (p< 0.05) for probiotic fed O. niloticus than the control. The hematology and blood plasma show significant differences (p< 0.05) in PD2 – PD5 when compared to the control. Fish fed PD5 had the best growth and immunity level

Nutritional status of palm kernel meal inoculated with Trichoderma Harzanium

The ability of Trichoderma harzanium to improve the nutritional status of palm kernel meal (P K M) was assessed over forty days of fermentation. Fermentation within this time period induced various changes in the proximate and mineral analysis of the palm kernel meal. Comparatively, the highest crude protein and ether extract of 33.03% and 8.65% respectively were obtained at 20 days of biodegradation by rrichoderma harzanium. As the fermentation period increases there was reduction in the crude fibre content of palm kernel meal from 14.45% at day 0 to 7.74 at day 10. There was increase in the quality of Ca (0.016%) potassium (0.170%) at day 10 and phosphorus (0.00073%) at day 20 when compared with the control. Key words: Nutritional status of PKM Trichoderma harzaniu

Antibiotic Susceptibility Profile and Survival of Bifidobacterium adolescentis and Bifidobacterium catenulatum of Human and Avian Origin in Stored Yoghurt

Bifidobacteria are categorized as health-promoting microorganisms (probiotics) in the gastrointestinal tracts of humans and animals. Antibiotic susceptibility is a key criterion for probiotic agent selection. Good survival of probiotics during storage at selected storage temperature(s) is highly desirable. Bifidobacteria isolated from human and chicken were thus characterized phenotypically by their ability to produce fructose-6-phosphoketolase enzyme. Eight selected isolates were then characterized on molecular basis employing genus-specific and species-specific 16S rRNA gene primers, and their antibiotic susceptibilities were also evaluated. Isolates were confirmed to be strains of B. catenulatum(4) and B. adolescentis (4). Studied strains were resistant to streptomycin, gentamycin, cloxacillin and cotrimoxazole but susceptible to  chloramphenicol, augmentin, amoxicillin and erythromycin. Three strains (B. catenulatum HM2, B. catenulatum HM3 and B. catenulatum HM5) showed atypical tetracycline resistance. B. catenulatum HM2, B. adolescentis CH2 and B. adolescentis CH3 showed significant reduction in counts (p < 0.05) and survived in adequate amount in yoghurt stored at 4¢ªC and -18¢ªC for 4 weeks. In addition to presenting acceptable antibiotic susceptibility profile and exhibiting good survival in stored yoghurt, the bifidobacteria isolates inhibited Staphylococcus aureus ATCC 25925 and Escherichia coli ATCC 25922 in-vitro and demonstrated potential for application as probiotic agents for human and agricultural purposes.Keywords: Bifidobacterium, probiotics, 16S rRNA, survival at low  temperature

The Effect of Walnut (Tetracarpidium Conophorum) Leaf and Onion (Allium Cepa) Bulb Residues on the Tissue Bacteriological Changes of Clarias Gariepinus Juveniles

In this study, the effect of walnut leaf (WL) and onion bulb (OB) residues on tissue bacteriology of Clarias gariepinus juveniles by dietary intake was investigated. Nine experimental diets: control (0%), OB2 (0.5%), OB3 (1.0%), OB4 (1.5%), OB5 (2.0%), WL6 (0.5%), WL7 (1.0%), WL8 (1.5%) and WL9 (2.0%) were formulated and replicated thrice at 40% crude protein. Fish (mean weight 7.4±0.02g) were fed twice daily at 3% body weight for 12 weeks. Microbiological analyses of water and fish (skin, gill, intestine and liver) and organ index (liver, spleen, kidney and heart) were investigated. Data were analysed using descriptive statistics and ANOVA at p=0.05. Results of enterobacteriacea and total viable count from this study revealed that bacterial loads on the water and fish of the experimental tanks were more affected by A. cepa and T. conophorum than the control for 4, 8 and 12 weeks and were significantly different (P<0.05) from the control. The values decreased in treated groups as the levels of inclusion (0.5%, 1.0%, 1.5% and 2.0%) increased and as the months increased. Also, organ index showed that the liver, heart, kidney and spleen were not significantly increased in all the treated groups and the control. The results suggest that walnut leaf and onion bulb residues inclusion in the diet of Clarias gariepinus could be a potential, less expensive and promising dietary supplementation that would positively influence growth, reduce and prevent bacterial infections in fish culture.La présente étude a examiné l’effet d’un apport alimentaire de résidus de feuilles de noyer (WL: walnut leaf) et de bulbes d’oignon (OB: onion Bulb) sur la bactériologie des tissus de Clarias gariepinus juvéniles. Neuf régimes expérimentaux - témoin (0%), OB2 (0,5%), OB3 (1,0%), OB4 (1,5%), OB5 (2,0%), WL6 (0,5%), WL7 (1,0%), WL8 (1,5% ) et WL9 (2,0%) - ont été préparés et répétés trois fois avec une teneur en protéines brutes de 40%. Des poissons (poids moyen 7,4 ± 0,02 g) ont été nourris à 3% du poids corporel deux fois par jour pendant 12 semaines. Des analyses microbiologiques de l’eau et des poissons (peau, branchies, intestin et foie) ont été effectuées, et l’indice d’organes (foie, rate, reins et coeur) a été étudié. Les données ont été analysées à l’aide de statistiques descriptives et de l’ANOVA à p = 0,05. Les résultats du dénombrement des enterobactériacées et le total des comptages viables de cette étude ont révélé que les charges bactériennes sur l’eau et les poissons des bassins expérimentaux ont été plus affectées par A. cepa et T. conophorum par rapport au groupe témoin pendant 4, 8 et 12 semaines et étaient significativement différentes (P <0,05) de celles du groupe témoin. Les valeurs ont diminué dans les groupes traités au fur et à mesure de l’augmentation des niveaux d’inclusion (0,5%, 1,0%, 1,5% et 2,0%) et des mois. De plus, l’indice d’organes a montré que le foie, le coeur, les reins et la rate n’avaient pas significativement augmenté de volume, que ce soit dans tous les groupes traités ou le groupe témoin. Ces résultats portent à croire que l’inclusion de résidus de feuilles de noyer et de bulbes d’oignons dans le régime alimentaire de Clarias gariepinus pourrait être envisagée comme une supplémentation alimentaire potentielle, moins coûteuse et prometteuse, capable d’avoir une influence positive sur la croissance, de réduire et de prévenir les infections bactériennes dans l’élevage de poissons.Mots-clés: charge microbienne; feuille de noyer; bulbe d’onion; Clarias gariepinus; bactérie