The aim of this study is to evaluate the effects of defatted colostrum (Col), defatted decaseinated colostrum whey, cheese whey, and spray-dried porcine plasma (SDPP) as supplements of a growth medium (de Man - Rogosa - Sharpe (MRS) broth) on the multiplication of lactic acid bacteria, probiotic bacteria, and potentially pathogenic Escherichia coli. Using automated spectrophotometry (in vitro system), we evaluated the effect of the 4 supplements on maximum growth rate (μ(max)), lag time (LagT), and biomass (OD(max)) of 12 lactic acid bacteria and probiotic bacteria and of an E. coli culture. Enrichment of MRS broth with a Col concentration of 10 g/L increased the μ(max) of 5 of the 12 strains by up to 55%. Negative effects of Col or SDPP on growth rates were also observed with 3 probiotic strains; in one instance μ(max) was reduced by 40%. The most effective inhibitor of E. coli growth was SDPP, and this effect was not linked to its lysozyme content. The positive effect of enrichment with the dairy-based ingredient might be linked to enrichment in sugars and increased buffering power of the medium. These in vitro data suggest that both Col and SDPP could be considered as supplements to animal feeds to improve intestinal health because of their potential to promote growth of probiotic bacteria and to inhibit growth of pathogenic bacteria such as E. coli.
Keywords: Bifidobacterium; Lactobacillus; antibiotics; antibiotiques; colostrum; dried porcine plasma; in vitro spectrophotometry; lysozyme; plasma porcin séché; spectrophotométrie in vitro.