Probiotics, prebiotics and competitive exclusion for prophylaxis against bacterial disease.

The microbial population of the intestinal tract is a complex natural resource that can be utilized in an effort to reduce the impact of pathogenic bacteria that affect animal production and efficiency, as well as the safety of food products. Strategies have been devised to reduce the populations of food-borne pathogenic bacteria in animals at the on-farm stage. Many of these techniques rely on harnessing the natural competitive nature of bacteria to eliminate pathogens that negatively impact animal production or food safety. Thus feed products that are classified as probiotics, prebiotics and competitive exclusion cultures have been utilized as pathogen reduction strategies in food animals with varying degrees of success. The efficacy of these products is often due to specific microbial ecological factors that alter the competitive pressures experienced by the microbial population of the gut. A few products have been shown to be effective under field conditions and many have shown indications of effectiveness under experimental conditions and as a result probiotic products are widely used in all animal species and nearly all production systems. This review explores the ecology behind the efficacy of these products against pathogens found in food animals, including those that enter the food chain and impact human consumers.

[Familial indifference to pain with somatosensory asymmetry: possible central anomaly]. / Forme familiale d'insensibilité à la douleur avec asymétrie de la somesthésie: anomalie centrale?

A family of seven siblings is described. The mother and six siblings have been examined, the eldest and youngest of whom suffer from congenital indifference to pain , although both were ticklish, and itched. The functions examined included somatosensory perception thresholds and autonomic functions; perception thresholds were greatly raised in the painfree subjects and to a lesser extent in some other family members, asymmetrically in all cases, being higher in the dominant hand. Painfree Subject 1 also underwent cerebrospinal fluid analysis at age 16, which showed normal B-endorphin levels but undetectable enkephalins. Electrophysiological tests when a child demonstrated notably that most (raised) measured values were lowered by naloxone. Light microscopic sural nerve biopsy performed on painfree Subject 1 in childhood did not suggest any abnormalities other than a thickened nerve sheath. Threshold asymmetry has not been observed in large numbers of subjects without neurological deficits. There were no significant autonomic changes in any tested family member, though there was some asymmetry. It is suggested that the findings may imply a congenital anomaly of the central nervous system which accounts for the somatosensory, biochemical, and electrophysiological abnormalities.