The Influence of Short-term and Continuous Administration of Lactobacillus casei on Basic Haematological and Immunological Parameters in Gnotobiotic Piglets

Two experiments were carried out on gnotobiotic piglets by model infection with the strain Escherichia coli O:8 K88⁺ Ent^- to investigate the influence of preventive, short-term and preventive continuous long-term administration of the Lactobacillus casei strain on basic haematological and immunological parameters. In each of the experiments, the animals were divided into experimental (EG1 and EG2, respectively) and control groups (CG1 and CG2, respectively). The pigs in the experimental groups were treated by L. casei (EG1, for 3 days; EG2, for 10 days) and the E. coli strain when 5 days old; the pigs in the control groups (CG1, CG2) were inoculated only with E. coli at the age of 5 days. In the first experiment, no significant differences in either of the parameters investigated were detected between the animals of the experimental (EG1) and the control group (CG1). In the second experiment, a significant difference (p < 0.05) in the percentage proportion of neutrophils (%Ne) and of phagocytic activity (%PA) was observed in the EG2 on day 7 of age. The percentage of lymphocytes (%Ly) was, on the contrary, significantly lower in the EG2 group (p < 0.05). Out of the haematological values observed, we detected significantly higher values of haematocrit (p < 0.05) and concentrations of haemoglobin (HG) (p < 0.05) in the experimental group EG2. Also, the index of phagocytic activity (IPA) in the EG2 group was 1.5-fold higher than that in the control group CG2. On day 5 after the administration of E. coli, i.e. on day 10 of age, significant differences were recorded between the groups in %Ne (p < 0.05) in favour of EG2 and in %Ly in favour of CG2 (p < 0.05). The EG2 group exhibited 2.5-fold higher percent of PA and more than twofold higher IPA. The comparison of both experimental groups (EG1 and EG2) showed a significant difference in %PA (p < 0.05), IPA (p < 0.01) and HG (p < 0.05) in the EG2 animals during the continuous inoculation with L. casei. The comparison presented indicates a more favourable effect of 10-days continuous administration of lactobacilli in comparison with 3-day short-term administration.