Separate and Synergic Effects of Lactobacillus uvarum LUHSS245 and Arabinogalactan on the In Vitro Antimicrobial Properties as Well as on the Fecal and Metabolic Profile of Newborn Calves

Simple Summary Diarrhea is common problem for young calves. It causes economic losses to cattle producers because for a newborn calf, diarrhea can be fatal. For this reason, calf diarrhea is an expensive disorder, often requiring prolonged medical treatment. Furthermore, treatment often requires use of drugs and antibiotics, increasing public concerns of excessive usage of drugs in dairy farming, and the development of antibiotic resistance. Therefore, prevention remains the best option, and the preventative strategies against newborn diarrhea aim to increase the immunity and the gut health status early after birth. One common prophylactic strategy against diarrhea is the use health-enhancing supplements in the feed. Our hypothesis is that a combination of different origins and mechanisms of action (lactic acid bacteria as an antimicrobial agent and arabibogalactan as a prebiotic for good microbiota stabilization), can lead to improvement in newborn calves' health parameters. In this study, the lactic acid bacteria strain, LUHS245, effectively inhibited the growth of pathogenic bacteria, as well being non-resistant to all the tested antibiotics. LUHS245, arabinogalactan, and its combination used for newborn calf feeding showed a desirable positive effect on newborn calf health parameters and it can be recommended in dairy farms for diarrhea prophylaxis. Abstract In this study, arabinogalactan (ARB) and Lactobacillus uvarum LUHS245 antimicrobial properties against pathogenic bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa 17-331, Acinetobacter baumanni 17-380, Proteus mirabilis, MRSA M87fox, Enterococcus faecalis 86, Enterococcus faecium 103, Bacillus cereus 18 01, and Streptococcus mutans) and resistance to antibiotics were evaluated and the role of their supplementation on the main metabolic and fecal variables of newborn calves was established. The animal trial involved 48 Holstein female calves randomly allocated in four homogeneous groups of 12 animals each, on the basis of body weight in the second day of life. Calves were fed with a standard milk replacer diet from the second day of life until 14th day, either unsupplemented or supplemented with 50 mL of LUHS245 (>= 7.5 log(10) CFU mL(-1)), 30 g of ARB, or with both (50 mL of LUHS245 and 30 g ARB). In vitro data showed that the LUHS245 inhibited the growth of Salmonella enterica and Bacillus cereus (inhibition zones 13.0 and 21.3 mm, respectively). Supplementation of LUHS245 and ARB either alone or together, lowered total bacterial count in the feces and reduced lactate and serum alanine aminotransferase concentrations in blood. This study showed that LUHS245 supplementation alone or together with ARB seemed to have some positive influence on certain health parameters in newborn calves. Further research with larger cohorts of animals is warranted to validate the beneficial effects of the tested supplements.