Antimicrobial activity of lactic acid bacteria multiplied in an alternative substrate and their influence on physiological parameters of new-born calves

Here, the ability of Pediococcus pentosaceus and Pediococcus acidilactici to utilise potato tuber juice for cell synthesis without an external nutrient supplement was investigated, and the influence of lactic acid bacteria (LAB) grown in this substrate on the growth performance of new-born calves, as well as blood biochemical and faecal microbiological parameters was evaluated. Calves were selected based on the analogy principle, treatment group (n = 21), control group (n = 27). Calves in the treatment group were administered 50 ml of fermented potato tubers juice containing 9.6 log CFU/ml of LAB mixture for 14 days. Also, determination of antimicrobial activities of tested LAB against a variety of pathogenic and opportunistic bacterial strains previously isolated from diseased cattle was performed. It was found that LAB supernatants effectively inhibited the growth of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Salmonella enterica, Corynebacter spp., Klebsiella pneomoniae, Enterococcus faecalis, and Bacillus cereus (the diameters of the inhibition zones varied between 11.0 ± 0.3 mm and 17.0 ± 0.6 mm). Thus, potato juice can be used as an alternative substrate for LAB cultivation (LAB cell concentration 9.6 ± 0.07 log CFU/ml). After lyophilisation (-48 °C) and spray-drying (+150 °C) viable cell concentrations in the fermented potato juice powder were 9.18 ± 0.09 log CFU/g and 9.04 ± 0.07 log CFU/g, respectively. The 50 ml of fermented potato tuber juice containing 9.6 log CFU/ml of LAB, administered every day for 14 days, reduced the risk of developing acidosis (stabilised blood pH; P < 0.05), reduced lactates and PCO2 concentration (P < 0.05) and the risk of liver lesions (reduced serum alanine aminotransferase concentration; P < 0.005) in blood and E. coli in the faeces of new-born calves.