Pinard-Van Der Laan M H, Monvoisin J L, Pery P, Hamet N, Thomas M
Laboratoire de Génétique Factorielle, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
Poult Sci. 1998 Feb;77(2):185-91. doi: 10.1093/ps/77.2.185.
Coccidiosis causes dramatic economic losses in the poultry industry. Next to the extensive use of anticoccidial drugs, improving genetic resistance of birds to this parasitic disease represents an attractive alternative. An experiment was run in order to identify lines of chickens resistant and susceptible to coccidiosis as a tool to search for genetic markers of resistance. Five outbred lines were used: two Egyptian lines (Mandarah and Fayoumi), a Rhode Island Red line, and two White Leghorn lines (WLB21 and WLDW). The WLDW line segregated for three MHC haplotypes, B15, B19, and B21, and for the sex-linked dwarf gene, DW. Chicks were challenged at 4 wk of age with a high dose of Eimeria tenella (150,000 oocysts) and slaughtered 8 d postinoculation. Innate resistance was assessed individually by measures of lesion score, mortality, and body weight gain at slaughter, and plasma coloration 4 d postinoculation. Large differences in resistance to E. tenella were observed between lines. The Fayoumi line appeared clearly as the most resistant line, showing no mortality, less severe lesions than other lines, and a 30% reduction of growth as compared to control birds. The WLDW line was the most susceptible, with 27% mortality and a 85% reduction in growth. No major effect of MHC or dwarfism on resistance to E. tenella was found.
球虫病给家禽业造成了巨大的经济损失。除了广泛使用抗球虫药物外，提高禽类对这种寄生虫病的遗传抗性是一种有吸引力的替代方法。为了确定对球虫病有抗性和易感性的鸡品系，以此作为寻找抗性遗传标记的工具，进行了一项实验。使用了5个远交系：两个埃及品系（曼达拉和法尤米）、一个罗德岛红品系以及两个白来航品系（WLB21和WLDW）。WLDW品系分离出三种主要组织相容性复合体（MHC）单倍型，即B15、B19和B21，以及性连锁矮小基因DW。雏鸡在第4周龄时用高剂量的柔嫩艾美耳球虫（150,000个卵囊）进行攻毒，并在接种后8天宰杀。通过病变评分、死亡率、宰杀时的体重增加以及接种后4天的血浆颜色等指标分别评估先天抗性。各品系对柔嫩艾美耳球虫的抗性存在很大差异。法尤米品系显然是抗性最强的品系，没有死亡情况，病变比其他品系轻，与对照鸡相比生长速度降低了30%。WLDW品系最易感，死亡率为27%，生长速度降低了85%。未发现MHC或矮小症对柔嫩艾美耳球虫抗性有主要影响。
