CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
In vitro fermentation of sugar cane molasses by chicks normal crop biota. Effect on Salmonella spp survival
Autor/es:
HIDALGO V. M.; APELLA M. C.
Lugar:
S. M. de Tucumán
Reunión:
Congreso; VII Congreso Agentino de Microbiología General. SAMIGE del Bicenternario; 2011
Institución organizadora:
SAMIGE
Resumen:
Salmonella is an important cause of clinical infections in poultry that act as a contaminant source in humans. The beneficial metabolic activity of the crop biota on the bird’s feed increases lactic acid and short-chain fatty acids (SCFA) concentrations that reduce the pH associated with a lower concentration of enteropathogens. Molasses is used by lactic bacteria as a carbon source for its readily fermentable sugars like glucose and sucrose. In this context, the ability of molasses to modify the crop microbial community and the survival of S. Gallinarum and S. Enteritidis in this ecosystem were evaluated. Additionally, sucrose (main molasses component) and lactose were studied and compared. An in vitro fermentation system for broiler chick crop homogenates in a basal fermentation medium was used with the addition of 1% (w/v) carbohydrates or without them (control) in microaerophilia for 6 h at 42 ºC. The pH was recorded at different times and, after 6 h incubation, the number of microorganisms was determined as well as lactic acid and SCFA concentration by HPLC. Survival rate of both Salmonella was evaluated by count in SSA medium. Molasses fermentation of the crop biota caused a sharp pH decrease 4 h later (4.7), significantly lower than that obtained for sucrose (5.8), lactose (7.4) and control (7.8). At 6 h, sucrose fermentation equalled the pH value obtained for molasses in the same period (4.4). Fermentation of the sugars led to an increase in total aerobes, enterococci and lactobacilli, while enterobacteria viability decreased 4 log units in presence of sucrose and molasses. The enterobacteria count did not show any significant differences in lactose and control. This result agrees with the low pH decrease during lactose fermentation as compared with those obtained in sucrose and molasses. Molasses fermentation generated the highest lactic, acetic, and formic acid concentrations that explain the pH reduction and the enterobacterial inhibitor effect. Sucrose fermentation led to a significant amount of lactic acid which was detrimental for the enterobacterial population. Lactic acid and SCFA contents, lactose fermentation products, were significantly lower than those found with the rest of sugars studied, which agrees with the results shown before. The inhibitory effect on S. Gallinarum and S. Enteritidis became evident after 6 h of molasses fermentation (reduction of 3 and 2 log units respectively). The fermentation products of sugars in molasses produced an enterobacterial population reduction and an important inhibitory effect on both Salmonella viability. In conclusion, the addition of small concentrations of molasses to the birds’ diet emerges as an interesting alternative to control enteropathogens like Salmonella. Supported by CONICET PIP 0996 and CIUNT D429.