TABLE 2.

Relationships of cell proliferation and alpha-toxin gene expression of C. perfringens in the ileal digesta of chickens on diets with or without bacitracin during the development of NE^a

Diet	Post challenge dayb	No. of infected birdsc	Log CFU/g (avg ± SD)d	No. of birds with lesions	Score (avg ± SD)	Alpha-toxin mRNA (log N/μg; avg ± SD)e
Nonmedicated	0	2	0.8 ± 2.0	ND	ND	0
	1	12	7.3 ± 1.7	ND	ND	5.1 ± 3.4
	2	10	6.7 ± 3.2	8	1.3 ± 1.0	7.4 ± 3.4
	3	10	6.2 ± 3.1	5	0.9 ± 1.2	6.2 ± 3.6
	4	6	4.1 ± 4.4	5	0.8 ± 1.0	3.7 ± 4.4
Medicated	0	1	0.5 ± 1.8	ND	ND	0
	1	0	0	ND	ND	0
	2	1	0.4 ± 1.3	0	0	0
	3	2	0.8 ± 1.3	1	0.1 ± 0.3	0
	4	3	1.1 ± 1.9	0	0	0

^aSamples were collected from 12 birds for each treatment. The nonmedicated diet contained no antibiotics; the medicated diet contained zinc bacitracin (55 mg/kg). ND, not determined; SD, standard deviation.

^bChickens were challenged with C. perfringens on day 18. On postchallenge day 0, samples were collected just before the challenge.

^cBirds were regarded as infected when C. perfringens was detected in the digesta.

^dLog₁₀ CFU per gram of ileal digesta.

^eN, copy numbers of alpha-toxin gene mRNA (regarded as 0 when the mRNA was not detected).