Prebiotic effects of oligosaccharides extracted from palm kernel expeller on different levels of Salmonella typhimurium infection in chicks

ARTICLES   Prebiotic effects of oligosaccharides extracted from palm kernel expeller on different levels of Salmonella typhimurium infection in chicks     S. RezaeiI, II; W.L. ChenI; S.C.L. CandyrineI, III; R.Q. FooI; M.F. JahromiI, IV; A.S. FarjamI; I. ZulkifliI; J.B. LiangI, # IInstitute of Tropical Agriculture and Food Security, University of Putra Malaysia, Serdang, 43400 Selangor, Malaysia IICentre of Excellence for Emerging and Re-emerging Infectious Diseases in Animals, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand IIIFaculty of Sustainable Agriculture, University Malaysia Sabah, 90509, Sandakan, Sabah IVAgriculture Biotechnology Research Institute of Iran (ABRII), East and North-East Branch, P.O. Box 91735/844, Mashhad, Iran     ABSTRACT Prebiotic effects of oligosaccharides extract from palm kernel expeller (OligoPKE) on Salmonella typhimurium were investigated in chicks in two experiments. Results of the first experiment showed that OligoPKE reduced the colonization of Salmonella typhimurium in the cecum and increased the immunoglobulin A (IgA) production in the blood and jejunum. The second experiment further investigated the prebiotic efficacy of dietary supplementation of OligoPKE on three levels of Salmonella typhimurium infection (1.0 x 104 Colony-forming unit (CFU)/mL; 1.0 x 106 CFU/mL and 1.0 x 108 CFU/mL) in chicks. OligoPKE reduced the colonization of Salmonella in the medium and high levels of infection. IgA level in serum and jejunum content increased significantly in all the three levels of infection when chicks received OligoPKE in their diet. Interleukin 8, and 10; interferon-α; and tumour necrosis factor genes were up-regulated in the jejunum of the infected chicks, and OligoPKE down-regulated these gene expressions. Results of the current study indicated that OligoPKE, an oligosaccharides extract from palm kernel expeller, is capable of reducing colonization of Salmonella typhimurium in young chicks, and boosted their immunity. Keywords: chicken, immunoglobulin, immune gene, microbial population     Introduction Salmonellosis can be caused by Salmonella contamination in poultry products at any stage of the production line, such as processing, distribution, retail marketing, handling and preparation (El-Aziz, 2013). In the Philippines, nearly 95% of human cases of salmonellosis are caused by contaminated poultry products (Sheffield et al., 2014). Annually, in the United States, 600 deaths and 1.4 million illnesses are reported because of Salmonella infection (Wang et al., 2015). One of the common non-typhoidal Salmonella strains that can cause salmonellosis is Salmonella typhimurium. Salmonella typhimurium is a pathogenic gramnegative bacterium that is found predominately in the gastro-intestinal tract. This strain of Salmonella has a wide range of animal reservoirs, high ability to spread, can survive in different environments, and is known for its rapid resistance to multiple drugs and antibiotics (Aktas et al., 2007). The use of prebiotics is one of the alternative approaches to prevent development of antibiotic resistance resulted from S. typhimurium infection in livestock farms. Several oligosaccharides, such as fructo-oligosaccharides (FOS) and mannan-oligosaccharides (MOS), inhibit the adherence of pathogens to epithelial cells and are classified as prebiotic sources (Gourbeyre et al., 2011; Ibuki et al., 2011; Samal & Behura, 2015). We recently reported that OligoPKE which contains mainly MOS exhibits prebiotic properties in experimental mice and chickens (Jahromi et al., 2015). In chickens, the highest mortality from S. typhimurium infection occurs in chicks less than two weeks old, when their immune system is not yet fully developed (Dunkley et al., 2009), Therefore, in this study, two experiments were designed to examine the prebiotic effects of OligoPKE on S. typhimurium at different infection rates on the immune systems of broiler chicks at neonatal age.   Materials and Methods Oligosaccharides were extracted from raw palm kernel expeller (PKE) using water (without enzyme) as solvent, following the procedure of Rezaei et al. (2015). Briefly, 1 L distilled water was added to 200 g ground PKE in a one-litre Scott bottle, shaken for 1 hour at room temperature, and later autoclaved. The insoluble materials were removed by centrifugation at 3000 g χ 5 min. The supernatant was filtered (Whatman filter paper no. 1) and the excess water was evaporated with a rotary evaporator (Hei-Vap Plug and Play Value 1, Heidolph Instruments, Swabach, Germany). Fatty acids were removed from the extraction with chloroform (two solvents/one extraction, shaken for 10 min, repeated two times). The excess solvent was evaporated using a rotary evaporator. Proteins were also removed from the extraction with acetonitrile (two solvents/one extraction, shaken for 10 min, repeated two times), and the excess solvent was (...truncated)