PREVALENCE, ULTRASTRUCTURE AND SUBTYPES OF Blastocystis IN CHICKENS (Gallus gallus) FROM PENINSULAR MALAYSIA

The frequent consumption of chicken products in Malaysia raises the concern about the risk for contracting Blastocystis infection from this consumption. We aimed to investigate the current prevalence, ultrastructure and subtypes of Blastocystis sp isolated from feces of free-range and barn-reared chickens in Peninsular Malaysia. Fresh fecal samples were collected and examined microscopically and cultured in Jones' medium supplemented with 10% horse serum. The infection rate was 26.2% (47 chickens were positive for Blastocystis out of 179 chickens) with significantly higher infection rate observed in the free-range chickens (34.3%; 36/105) compared to the barn-reared population (14.9%; 11/74) (p=0.004). The most common form of the organism seen on culture was vacuolar form. The sizes seen on culture ranged from 10 µm to 100 µm. The cell bodies stained with Sudan Black B were positive for lipids. On examination with electron microscopy, smooth surface and electron-dense central vacuoles were seen in the cell bodies of those isolated from the free-range chickens but not the barn-reared chickens which consists of coarse surface and electron-opaque central vacuole. Blastocystis isolates were subsequently subjected for DNA barcoding method and four subtypes were identified. This is the first published study to evaluate the prevalence, surface structure, ultrastructure and subtypes of Blastocystis sp isolated from free-range and barn-reared chicken in Malaysia.