The Inheritance of Resistance to Cecal Coccidiosis in the Domestic Fowl

Exoerythrocytic development of Plasmodium gallinaceum in the White Leghorn chicken

“…ii) We excluded the possibility that our chicks harbored residual coccidiostats, which are frequently included in chicken feed to prevent devastating outbreaks of the related apicomplexan parasite Eimeria tenella (Takaya et al, 1999;Pines et al, 2000), which could have affected the exoerythrocytic stages of P. gallinaceum. iii) One remaining possibility is that White Leghorns have gained resistance to tissue stages of P. gallinaceum, because modern commercial chicken breeds have been selected for increased resistance to disease, including E. tenella infection (Edgar et al, 1951;Champion, 1954;Rosenberg et al, 1954;Johnson and Edgar, 1982;Caron et al, 1997). 4) Finally, the quinine used in the 1940s may have been of lesser purity thus permitting the generation of secondary exoerythrocytic stages from a low level parasitemia.…”

The Response of Commercial Egg Production Stocks to Experimental Infection With Eimeria tenella and its Relation to Field Mortality

“…Samples of the Cornell Randombred control were included in all tests to provide a standard of comparison. The test procedure was essentially that first described by Ro- senberg et al (1948) and later elaborated by Champion (1954). Chicks were reared in an electrically heated battery brooder in a coccidia free room.…”

Influence d'une sélection sur le comportement sur la réponse à l'infection coccidienne chez la poule

“…F,ri 1931 , KRAI,I,ING!R et C HODZ iESNER ont mis en évidence les différences de sensibilité à l'infection coccidienne entre volailles de races Leghorn, Faverolles et leurs croisements. Si la possibilité d'une sélection vis-à-vis de la coccidiose caecale à E. tenella a été démontrée (M AY GE W , 1934 ;HE RR IC K et al, 1935 ), différents travaux permettent de penser que la résistance obtenue n'est que partielle (Rosl; N-BERG et al, 1954;CHAMPION, 1954). Plus récemment, J!xx!RS et al ( 1970 ) ont constaté avec E. tenella qu'une sélection sur le critère mortalité ne permettait pas d'obtenir des individus plus résistants au parasitisme.…”