Abstract:
The study was aimed to determine the antibodies concentration level against Heterakis gallinarum of two genotypes of Sudanese local chickens (n=157), that raised under free-range laying hens system, and originated from two different agro-climatic zones in central and east of Sudan, namely Khartoum and Gadarif zones in wet and dry seasons where in each zone five villages were randomly considered. The plasma samples were obtained individually from the two genotypes Large Baladi (LB) (n=80) and Bare-neck (BN) (n=77), to measure antibodies concentration level via the enzyme linked immunoglobulin assay (ELISA) based on developed Ascaridia galli antigens. Worm burden was determined by worm count after slaughtering. Reliable and specific determination methods of the exposure of the chickens to H. gallinarum determine cutoff point (antibody titre = 71.09) between known infected and non-infected chickens. Receiver-operating characteristic (ROC) curve revealed an area under the curve (AUC) was 0.823±0.04, with an estimated sensitivity and specificity of the assay were 55% and 100%, respectively. Regarding the antibodies level of H.gallinarum, the variation in Khartoum and Gadarif States was (0.08), and (0.64) respectively between the two genotypes of chicken with significant variance (0.04) between the dry and wet seasons. Also the significant differences (p<0.05) between interaction of regions and seasons and between regions and genotype were observed with 0.20 and 0.30 respectively. The correlation between the antibody titre and worm burden showed no significant association between them (r= 0.034, P= 0. 701). We conclude that ELISA serves as a good and effective diagnostic tool, also the antibodies developed against A. galli can be used to identify H. gallinarum in infected chickens.
