Browsing by Author "Saleh, Mayra Anton Dib"
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- Development of a chicken gastrointestinal tract (GIT) simulation model: impact of cecal inoculum storage preservation conditionsPublication . Carvalho, Nelson Mota de; Costa, Célia Maria; Castro, Cláudia; Saleh, Mayra Anton Dib; Pintado, Manuela Estevez; Oliveira, Diana Luazi; Madureira, Ana RaquelA chicken gastrointestinal tract (GIT) simulation model was developed to help predict the potential effects of feed additives supplementation on chicken’ microbiota. The chemical and enzymatic conditions for oral, gastric, intestinal, and cecum fermentation phases were designed to closely resemble the chicken GIT conditions. For cecum fermentation, the inoculum was obtained from the cecal contents of 18 38-day broiler chickens. The impact of inoculum preservation on bacteria viability was assessed by comparing two methods of preservation with fresh inoculum: (1) 5% dimethyl sulfoxide (DMSO) at −80 °C and (2) 30% glycerol at −20 °C. The fermentation with fresh and frozen (DMSO method) inoculums was performed and compared using standard chicken feed (SCF) and SCF with 1% fructooligosaccharides (FOS), and inoculum control (IC) condition without feed matrix was used as a baseline. Inoculum’s viability was assessed throughout 90 days of storage by culture media platting, while bacterial growth and metabolites production during fermentation was evaluated by quantitative polymerase chain reaction (qPCR), high-performance liquid chromatography (HPLC), and total ammonia nitrogen quantification. The DMSO method was shown to be the most suitable for cecal inoculum storage. Higher growth of beneficial cecal bacteria for fresh inoculum was observed in SCF while for frozen inoculum, was the SCF + FOS condition. Also, frozen inoculum had lower activity of butyrate producers and proteolytic bacteria, showing different fermentation profiles. The GIT model developed showed to be useful to test the effect of feed additives supplementation.
- Importance of gastrointestinal in vitro models for the poultry industry and feed formulationsPublication . Carvalho, Nelson Mota de; Oliveira, Diana Luazi; Saleh, Mayra Anton Dib; Pintado, Manuela Estevez; Madureira, Ana RaquelThe animal’s diet is a crucial factor, as poultry feed formulations influences greatly their development, well-being and final products quality, i.e., meat and eggs. Therefore, the search for feed additives that provide concomitantly better performances, low-cost usage, guarantying the animal well-being and products safety, became a priority to the poultry industry. Although in an early stage, research has been focused on developing the optimal cost-efficient feed formulations, taking into account the chicken’s physiology and function of the gastrointestinal tract and intestinal microbiota. This review discusses a number of concepts and novel approaches towards the optimization of poultry’s feed formulations, by critically encompassing the animal’s growth and performance. Additionally, it highlights the in vitro gastrointestinal models capabilities as a potential solution to test highly nutritive, well-balanced and efficient feed formulations within a circular economy framework.
- Preservation of human gut microbiota inoculums for in vitro fermentations studiesPublication . Carvalho, Nelson Mota de; Oliveira, Diana Luazi; Saleh, Mayra Anton Dib; Pintado, Manuela; Madureira, Ana RaquelThe use of fecal inoculums for in vitro fermentation models requires a viable gut microbiota, capable of fermenting the unabsorbed nutrients. Fresh samples from human donors are used; however, the availability of fresh fecal inoculum and its inherent variability is often a problem. This study aimed to optimize a method of preserving pooled human fecal samples for in vitro fermentation studies. Different conditions and times of storage at -20 degrees C were tested. In vitro fermentation experiments were carried out for both fresh and frozen inoculums, and the metabolic profile compared. In comparison with the fresh, the inoculum frozen in a PBS and 30% glycerol solution, had a significantly lower (p < 0.05) bacterial count (<1 log CFU/mL). However, no significant differences (p < 0.05) were found between the metabolic profiles after 48 h. Hence, a PBS and 30% glycerol solution can be used to maintain the gut microbiota viability during storage at -20 degrees C for at least 3 months, without interfering with the normal course of colonic fermentation.