Data and code accompanying Figure 1c. Raw data of colony counts converted to cell densities in CFU/ml (processed in Excel) is presented in file "Dec19_raw_colony_counts_conjug_assay_20210326". Columns are described as follows: Experiment= medium that was used for assay. Control media: 1.0x_VL and 1.2x_VL. Supernatant medium (Sup) number is labelled. Replicate = Biological replicate assay Time = time since start of assay in hours R = strain R (recipient) C = strain T (transconjugant) D = strain D (donor) Processed data of cell densities were copied and formatted in the following data file, taking averages across technical replicate densities: "Dec19_conjug_assay_cell_densities_t0_4_allreps". N = sum of R, C and D densities Conjugation rates were calculated using code "20210326_ConjugationAnalysis_Huisman_method.R" with input of code from "20191024_ConjugationParameterMethods.R", strain growth rate data from "Dec19_growth_rates_D_R_C_allreps.csv" and strain density data from "Dec19_conjug_assay_cell_densities_t0_4_allreps.csv". Output conjugation rates were copied and formatted into Excel in data file: "20201027_Figure1c_conjug_rates_huisman_4h.csv". Columns were labelled as follows: Donor = donor strain (D) in conjugation assay Treatment_group = Description of lactic acid bacterial genus from which supernatant medium was produced and replenished with nutrients for the growth assay. Control treatment is supernatant-free nutrient medium. Treatment = Category of medium, either control or supernatant Medium = description of medium type. 1.0x or 1.2x relate to concentration of all nutrients in VL medium. Sup refers to supernatant medium number. Replicate = Biological replicate assay Conjugation_huisman = conjugation rate in ml cell^-1 h^-1 using the method of Huisman et al., 2020; bioRxiv log10_huisman = log base 10 conversion of conjugation rates Statistical analysis of conjugation rates between control and supernatant media conditions was completed using code: "20210911_ANOVA_Dunnett_GrowthRate_ConjugRate.R" with input of data file "20201027_Figure1c_conjug_rates_huisman_4h.csv". The data plot was created using code: "20210326_Figure1bc_plot.R".