Investigation On The Occurrence of Yeast Species in the Digestive Tracts of Broiler

From the intestinal tracts of 35 out of 50 birds 58 yeast isolates belonging to 3 genus and 6 species were obtained. The occurrences of individual yeast species were Saccharomyces (31.03 %), Candida glabrata (20.69 %), C. tropicalis (15.51 %),C . albicans (15.51 %), C . fmata and Creptococcus neoformans (8.62%) . Introduction: The gastrointestinal tract is the major digestive and absorbing organ and it plays a crucial role in chicken growth (Amit-Romach et al.(2004). A diverse micro biota is found throughout the tract and is most extensive in the cecum (Barnes, 1972; Buckley, 1989; Mead &Adams, 1975; Mead, 1997). This microflora has a role in nutrition, detoxification of certain compounds, growth performance, and protection against pathogenic bacteria. The gut microflora influences health and well-being of host animals (Van Uden & Castelo-Branrco, 1963; Nurmi, & Rantala, 1973; Mead, 1997; Vispo & Karasov, 1997;). In poultry, the absence of normal micro flora in the cecum has been considered a major factor in the susceptibility of chicks to bacterial infection (Barrow, 1992; Van der Wielen et al.2002). The occurrence of bacteria as natural occupants of the intestinal flora of poultry is well documented. The incidence and composition of the yeast micro flora, however, have received little attention (Laubscher et al., 2000). The attention has been given to the intestinal yeast flora of several mammal and bird species, but little to poultry(Van Uden & Castelo-Branrco, 1963). Saccharomyces cerevisiae is probably a facultative intestinal saprophyte; it was isolated previously from humans and horses and from swine (Mcginnis,1980). Candida spp. are frequently encountered human and veterinary pathogens causing mucosal and invasive candidiasis. (Deborah et al., 1987; Lazarus & Koburger, 1974). The specific instance of avian candidiasis is either a primary or secondary infection most often due to infection with Candida albicans, Candida krusei, or Candida tropicalis. ( Kano et al.,2001) Cryptococcus neoformans has a world – wide distribution and is a major cause of all clinical types of cryptococcosis. It has been isolated from various sources in nature and is noted for its association with accumulations of avian guano. Cryptococcosis is a chronic, sub acute to acute pulmonary , systemic or meningitic disease, initiated by inhalation of desiccated yeast cells of Cryptococcus neoformans. Cryptococcosis is the most common systemic fungal infection of cats. Definitive diagnosis of Cryptococcosis is based on cytological, histopathological , or culture demonstration of the organism. ( Barrow,1992; Fell & Van Uden,1963) However, direct microscopic examination is a rapid but quite insensitive test and strongly depends on the operator’s skills A study was undertaken with the objective of identifying the predominant yeasts associated with the intestinal tracts of chickens, It was thought of interest to examine whether chickens are, Coll. Of Agric. / Univ. of Babylon RESEARCHES of THE FIRST INTERNATIONAL CONFERENCE (BABYLON AND RAZI UNIVERSITIES) ( 2011) 73 ISSN 2072-3875 in general, suitable hosts for intestinal yeasts and to obtain information on the population of their intestinal yeast flora. Methods : Isolation mediumwas prepared as following : Agar . 20.0g Glucose . 20.0g Neopeptone . 10.0g Preparation of Medium: Add components to distilled/deionized water and bring volume to 1.0L. Mix thoroughly. Gently heat and bring to boiling. Distribute into tubes or flasks. Autoclave for 15 min at 15 psi pressure–121°C. Pour into sterile Petri dishes. Isolation. samples were taken from rectal contents. Weighed portions of the samples were suspended in sterile water and serial dilutions plated in isolation medium. After incubation at 37" for 48-72 hr, the numbers of yeast colonies were recorded according to macroscopic and microscopic morphology. Representatives of each type were sub cultured for later identification. Identijcation of the yeast isolates. The methods described by( Koneman , 1978 ; Mcginnis,1980; Hoog De & Guarro, 1995) were used. Results : From the intestinal tracts of 35 out of 50 birds 58 yeast isolates, belonging to 3 genus and 6 species were obtained table (1). The occurrences of individual yeast species were Saccharomyces spp (31.03 %), Candida glabrata (20.69 %), C. tropicalis (15.51 %),C . albicans (15.51 %), C . fmata and Creptococcus neoformans (8.62%) Table (2). The species of yeast isolated and their respective incidences and the average number of colony-forming units/g. wet intestinal contents are listed in table (3). Table1. Yeast species from the intestinal tracts of 35 birds No of birds positive Yeast isolates 9 Saccharomyces spp Candida glabrata 7 Saccharomyces spp C . albicans 6 C. tropicalis C . albicans 4 C . fmata 3 Candida glabrata C. tropicalis 3 Creptococcus neoformans 2 Saccharomyces spp C . albicans Creptococcus neoformans 1 C . albicans C . fmata Total 35 RESEARCHES of THE FIRST INTERNATIONAL CONFERENCE (BABYLON AND RAZI UNIVERSITIES) ( 2011) 73 ISSN 2072-3875 Table 2. The occurrences of individual yeast species from the intestinal tracts of 35 bird Yeasts isolated No. of birds positive (more than one yeast genus on one bird) Percentage incidence of yeast species(%) Saccharomyces spp 18 31.03 Candida glabrata 12 20.69 C. tropicalis 9 15.51 C . albicans 9 15.51 C . fmata 5 8.62 Creptococcus neoformans 5 8.62 total 58 100 Table 3. The average number of colony-forming units/g. wet intestinal content Species isolated Total yeast count/(cfu/g) Saccharomyces spp. 8.8 *10 3 Candida glabrata 9.8*10 3 C. tropicalis 7.9*10 3 C . albicans 8.9*10 3