Production of a Potentially Probiotic Product for Animal Feed and Evaluation of Some of Its Probiotic Properties

Abstract

Nowadays, probiotics have been proposed for substituting antibiotics in animal feed since the European Union banned the latter compounds in 2006 to avoid serious side effects on human health. Therefore, this work aimed to produce a probiotic product for use in animal feed by fed-batch fermentation of whey with a combination of kefir grains, AGK1, and the fermented whole milk used to activate these kefir grains. The probiotic culture obtained was characterized by high levels of biomass (8.03 g/L), total viability (3.6 × 108 CFU/mL) and antibacterial activity (28.26 Activity Units/mL). Some probiotic properties of the probiotic culture were investigated in vitro, including its survival at low pH values, under simulated gastrointestinal conditions, after freezing in skim milk at −20 °C, and in the commercial feed during storage at room temperature. The viable cells of lactic and acetic acid bacteria and yeasts exhibited higher tolerance to acidic pH and simulated gastrointestinal conditions when the cells were protected with skim milk and piglet feed, compared with washed cells. The results indicated the feasibility of producing a probiotic product at a low cost with a potential application in animal feed.

Impact of Storage Temperature on Microbial Diversity and Probiotic Effect of Liquid Brewers’ Yeast

“…The pH declined, stabilized, and increased slightly towards day 20. The findings correspond with those of other researchers who attributed such a shift in pH to the consumption of organic acids (lactic and acetic) by yeast present in the microbiota of such by-products [27]. The pH is an essential parameter in LBY preservation.…”

Chemical, Microbiological and Volatile Composition of Kefir-like Beverages Produced from Red Table Grape Juice in Repeated 24-h Fed-batch Subcultures

“…The OD values were converted to cell dry weight (CDW) from a standard curve (CDW vs OD) to quantify the free biomass released from the kefir grains into the culture medium. 19,77 Concentrations of glucose, fructose, ethanol, glycerol, lactic acid and acetic acid were quantified by a high-performance liquid chromatography (HPLC) system equipped with an ION-300 Organic Acids column (length 300 mm, internal diameter 7.8 mm) with a precolumn IONGUARD™ (polymeric guard column), both obtained from Tecknokroma S. Coop. C. Ltda, Barcelona, Spain.…”

“…For activation 77 , the kefir grains were separated from the coverage liquid (milk) by filtration through a plastic strainer, weighed (approximately 30.6 g, wet weight) and added to a 1 L Pyrex bottle containing 1 L pasteurized whole milk UHT. Subsequently, the bottle was covered with a cheesecloth and it was secured with a rubber band and incubated at room temperature away from direct sunlight, at room temperature at 150 rpm for 24 h. Then, the kefir grains were separated from the fermented milk under sterile conditions by filtration through a plastic strainer, washed with sterile distilled water and after the second activation in milk, the grains were used as the inoculum for the production of the kefir-like beverages.…”

Main Composition and Visual Appearance of Milk Kefir Beverages Obtained from Four Consecutive 24- and 48-h Batch Subcultures

“…However, the bacterial counts of the three microbial groups by day 28 always surpassed the minimal number of probiotic cells needed to observe a probiotic effect on the host [101]. Additionally, it is expected that a high number of these cells can reach the intestine and colonize it, as it has been suggested that the food matrix (milk) can protect these cells against gastrointestinal conditions [101,104].…”