Feed supplementation of Lactobacillus plantarum PCA 236 modulates gut microbiota and milk fatty acid composition in dairy goats--a preliminary study

Abstract

This study aimed to evaluate the potential of a promising Lactobacillus plantarum isolate (PCA 236) from cheese as a probiotic feed supplement in lactating goats. The ability of L. plantarum to survive transit through the goat gastrointestinal tract and to modulate selected constituents of the gut microbiota composition, monitored at faecal level was assessed. In addition, L. plantarum effects on plasma immunoglobulins and antioxidant capacity of the animals as well as on the milk fatty acid composition were determined. For the purpose of the experiment a field study was designed, involving 24 dairy goats of the Damascus breed, kept in a sheep and goat dairy farm. The goats were divided in terms of body weight in two treatments of 12 goats each, namely: control (CON) without addition of L. plantarum and probiotic (PRO) treatment with in feed administration of L. plantarum so that the goats would intake 12 log CFU/day. The experiment lasted 5 weeks and at weekly time intervals individual faecal, blood and milk samples were collected and analysed. All faecal samples were examined for the presence of L. plantarum PCA 236. In addition, the culturable population levels of mesophilic aerobes, coliforms lactic acid bacteria (LAB), Streptococcus, Enterococcus, mesophilic anaerobes, Clostridium and Bacteroides in faeces were also determined by enumeration on specific culture media. In parallel, plasma IgA, IgM and IgG and antioxidant capacity of plasma and milk were determined. No adverse effects were observed in the animals receiving the lactobacillus during the experiment. Lactobacillus plantarum PCA 236 was recovered in the faeces of all animals in the PRO treatment. In addition, PRO treatment resulted in a significant (P<or=0.05) increase in LAB coupled with a significant decrease in faecal clostridia populations compared to the CON treatment. The antioxidant capacity and the concentrations of immunoglobulins IgA, IgM and IgG in goat plasma did not differ between the treatments. In contrast, milk fat composition in the PRO treatment had a significantly higher content of polyunsaturated fatty acids such as linoleic, a-linolenic and rumenic acids compared to CON, while there were no differences in milk antioxidant capacity. The results obtained in this study, indicate that the L. plantarum PCA 236 strain has displayed an interesting probiotic potential, in terms of beneficially modulating the goat faecal microbiota and milk fatty acid composition that needs to be further researched.