http://informahealthcare.com/ijf ISSN: 0963-7486 (print), 1465-3478 (electronic) Int J Food Sci Nutr, Early Online: 1–5 ! 2014 Informa UK Ltd. DOI: 10.3109/09637486.2014.979313 RESEARCH ARTICLE Brain and liver fatty acid composition changes upon consumption of Lactobacillus rhamnosus LA68 Nevena Ivanovic 1 , Rajna Minic 2 , Ivana Djuricic 1 , Ljiljana Dimitrijevic 2 , Sladjana Sobajic 1 , Irena Zivkovic 2 , and Brizita Djordjevic 1 1 Department of Bromatology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia and 2 Department of Research and Development, Institute of Virology, Vaccines and Sera, Torlak, Belgrade, Serbia Abstract Recent reports suggest that the metabolic activity of the enteric microbiota may influence the fatty acid composition of the host tissue. There are many studies dealing with the influence of lactobacilli on various pathological conditions, and some of the effects are strain-specific. This study was designed to test the effects of a particular Lactobacillus strain, Lactobacillus rhamnosus LA68 on fatty acid composition of the liver and the brain of C57BL/6 mice in the absence of an underlying pathological condition. Female mice were supplemented with live L. rhamnosus LA68 bacteria for the duration of 1 month. Serum biochemistry was analyzed and liver and brain fatty acid composition was assessed by gas-liquid chromatography. Significant changes in liver and brain fatty acid composition were detected. In the liver tissue we detected an increase in palmitoleic acid (p ¼ 0.038), while in the brain compartment we found an increase in palmitic (p ¼ 0.042), stearic (p ¼ 0.017), arachidonic acid (p ¼ 0.009) and docosahexaenoic acid (p ¼ 0.004) for control versus experimental group. These results show discrete changes caused by LA68 strain consumption. Even short duration of administration of LA68 influences the fatty acid composition of the host which adds to the existing knowledge about Lactobacillus host interaction, and adds to the growing knowledge of metabolic intervention possibilities. Keywords Brain, fatty acid composition, Lactobacillus rhamnosus LA68, C57BL/6, liver History Received 2 April 2014 Revised 8 October 2014 Accepted 18 October 2014 Published online 27 November 2014 Introduction Human intestinal microbiota has been found to harbor trillions of microorganisms, with 150–200 different prevalent bacterial species (Clemente et al., 2012; Turnbaugh et al., 2006). These bacteria have 100-times more genes than the human genome (Qin et al., 2010), including genes that provide additional benefits to the host. For example, the intestinal microbiota has several indispensible roles for mammals, such as vitamin K and B production, food processing, digestion of complex indigestible polysaccharides, etc. Intestinal microbiota also has a significant impact on human health through enhancement of intestinal function, modulation of immune system and hypocholesterolemic effects (Kang et al., 2013). The generation of germ free (GF) animals was a valuable tool for elucidating the true impact of microbiota. GF animals can experience sudden death due to cecal volvulus (Djurickovic et al., 1978), and the average body weight and fat tissue volume tend to be smaller in some strains of GF animals. Further investigation led to conclusion that the gut microbiota acts as regulator of fat storage (Ba ¨ckhed et al., 2004) and contributes to a fatty liver phenotype in insulin-resistant mice (Dumas et al., 2006). Probiotics or live microbes which, when administered in adequate amounts, may confer health benefits to the host (FAO & WHO, 2001), may positively affect the gut microbiota and be effective in the prevention and treatment of specific pathological conditions (Collado et al., 2009; Pineiro et al., 2008). Lactobacilli and Bifidobacteria are the genera most widely used as probiotics. Lactobacilli belong to the Firmicutes phyla, which is the most abundant phyla in adult individuals. The ratio of Firmicutes to Bacteroides, the second most abundant phyla in the human gut, has been found to increase in obesity (Ley et al., 2006), which was explained by increased efficiency of microorganisms of energy extraction from the diet, and by short chain fatty acid production, which can be used for de novo lipid synthesis (Turnbaugh et al., 2006). Because of relatively low production costs and looser regula- tions for oral supplements, LAB are more intensively tested for effects on many different pathological conditions. The proven beneficial affects comprise of stimulation of the immune system (Kapila et al., 2013; Sharma et al., 2013), allergy amelioration (Kallioma ¨ki et al., 2001, 2003; Kallioma ¨ki & Isolauri, 2004); and treatment of rotavirus diarrhea in children (Guandalini et al., 2000; Shornikova et al., 1997). Although there are many studies dealing with the influence of probiotics, especially lactobacilli on different physiological processes and pathological conditions, and some of these effects are strain-specific, the question arises as to whether Correspondence: Nevena Ivanovic, Department of Bromatology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia. Tel: +381 11 3951 393. Fax: +381 11 3972 840. E-mail: nevenam@pharmacy.bg.ac.rs Int J Food Sci Nutr Downloaded from informahealthcare.com by Nevena Ivanovic on 11/28/14 For personal use only.