Judul: Study of kampung chicken resistance against Salmonella enteritidis using TLR4 gene as marker.
Abstrak: Kampung chicken is a kind of Indonesian local chicken that do not have special characteristic and spread out in various regions of Indonesia. Kampung chicken eggs is trusted by the majority of Indonesian people to increase stamina and to heal diseases. Therefore Kampung chicken eggs was mostly used by Indonesian people as ‘jamu’ (a potion) or as an ingredient of potion that it was directly consumed without cooking. Salmonella free eggs become significant in producing the safe ‘jamu preparation’ so that the users of Kampung chicken eggs be spared from salmonellosis. Salmonella free eggs might be produced by chickens which have high resistancy to this bacteria. One of excellent markers showing resistance of chicken against Salmonella is an active Toll-like Receptor 4 (TLR4) gene. TLR4 gene was associated with non-specific immune response, because it transcribes TLR4 protein, which is a phagocytes cell surface receptor that plays a role to recognize lipopolysaccaride of gram negative bacteria including Salmonella sp. The aim of the research was to prove resistance of Kampung chicken against S. enteritidis, using TLR4 gene as marker. The evidence was done by analyzing the association between genotype TLR4 gene with the factors that indicate the resistance to these bacteria that was obtained from molecular and biological assays. To identify the genotype TLR4 gene, 50 Kampung chickens was genotyped using PCR-RFLP technique (the first stage of these study). The second stage was conducted tests on several chickens resistance indicators against S. enteritidis from natural infection. The third stage in these research was testing resistance of chickens when was challenged with S. enteritidis (ID50 dose : 105 cfu ml-1), through molecular and biological assays. Then the test results were associated with genotype of TLR4 gene, and it was analyzed by ANOVA (analysis of variance). The results showed that the PCR-RFLP technique in exon 2 of TLR4 gene was identified that this gene on the Kampung chicken was polymorphic. A presence of mutation was detected on site 3924. This mutation caused bases change from guanine to adenine (GA). From this genotyped was found three kinds of genotype TLR4 gene. They were AA, AG and GG. GG genotype dominated the genotype frequencies of TLR4 gene of Kampung chickens. AA genotype was only found on one individual Kampung chicken, so in subsequent association analysis was not included in the statistical test. The second stage of this study showed that in all of TLR4 gene genotypes of the Kampung chicken was not found S. enteritidis in the blood and eggs produced. In the blood serum of Kampung chicken positive was found IgY specific S. enteritidis (in all genotypes). Egg yolk that produced by Kampung chicken was found specific IgY of S. enteritidis in high concentrations (2.47-3.58 mg ml-1). On all genotypes, the concentration of leucocytes and differentiation of leucocytes were in the range of physiological normal. Kampung chickens which were challenged with S. enteritidis not impaired physiological, it is seen from the results the concentration of leucocytes and differentiation of leucocytes assays that were still in the normal range. Although the Kampung chicken was challenged with S.
Keyword: Kampung chicken, TLR4 gene, TLR4 gene, non specific immune response, S. enteritidis