The in vivo and in vitro effect of a fructooligosaccharide prebiotic combined with alfalfa molt diets on egg production and salmonella in laying hens
Donalson, Lisa Michelle
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Salmonellosis affects an estimated 1.4 million people a year with a great majority of cases never being reported. Salmonella Enteritidis (SE) can be found in a variety of foods including poultry meat and eggs. Susceptibility of SE colonization is increased by molting. Induced molting is used in the poultry industry to rejuvenate the hen??s reproductive tract and increase post molt egg quality and production. The most common molting method is complete feed withdrawal. Recent animal welfare pressures have encouraged the industry to seek alternatives to feed withdrawal with one alternative being feeding a high fiber diet like alfalfa. Alfalfa is high in protein, but low in energy which is desirable for a molt diet. Alfalfa??s fermentation properties have been thought to be an inhibitor in pathogen colonization during molting. Including a prebiotic such as fructooligosaccharide (FOS) in the molt diet is thought to further decrease colonization while benefiting the indigenous microflora. Laying hens were molted using alfalfa combined with different ratios of layer ration in an in vivo experiment. The hens responded comparably to the alfalfa molt dietsas they did to feed withdrawal as far as post-molt production parameters were concerned, thus showing that alfalfa was a viable alternative molt diet. Two in vitro studies were designed to evaluate the fermentation properties of alfalfa and layer ration combined with the prebiotic FOS and their abilities to inhibit Salmonella growth. Each treatment was combined with diluted cecal contents and allowed to ferment. The results showed that the most fermentation occurred when alfalfa was the substrate and was slightly increased with the addition of FOS. In addition, combining FOS with alfalfa inhibited Salmonella growth. To integrate these results, an in vivo study was preformed using an alfalfa/layer ration diet from the previous in vivo study with FOS. Volatile fatty acids and lactic acid measurements were made to evaluate fermentation while Salmonella colonization was measured in pertinent organs and in fecal shedding. The results of this study further substantiate alfalfa as a molt diet and conclude that the addition of FOS does, while not statistically significant, further inhibit Salmonella colonization.