Developing an experimental necrotic enteritis model in turkeys - the impact of Clostridium perfringens, Eimeria meleagrimitis and host age on frequency of severe intestinal lesions

Table 2 Effect of sampling time, challenge and age on frequency of severe intestinal lesions

Study variable	Study variable level	CP¹	EM dose²	Hours after EM³	Experiments	No. of birds (gut contents)⁴	% score3	OPG⁵
Hrs post	97–99	1	1.6–15	–	3,4	34 (10)	< 3.0^a	0^a
EM⁶	121–149	1	1.6–15	–	3,4	91 (20)	29.7^b	5.8^b
(3-wk-old)	168–171	1	1.6–15	–	3,4	38 (9)	18.4^ab	5.0^b
	123–129	1	5–20	–	1,4,9	53 (16)	64.2^c	6.3^e
	145–147	1	5–20	–	1,4,9⁷	59 (10)	1.7^d	5.4^e
	125	1	10–20	–	9	8 (2)	12.5^g	4.6^e
	145	1	10–20	–	9	15 (2)	6.7^g	6.2^f
(5-wk-old)	125	1	10–20	–	9	8 (2)	75.0^c	4.6^e
	145	1	10–20	–	9	17 (2)	76.5^c	6.1^f
Challenge	None	0	0	119–171	1,2,3,4,5	50 (12)	< 2.1^a	0^a
(3-wk-old)	EM⁸	0	0.25–20	119–171	1,2,3,4,5	77 (16)	6.5^a	5.5^b
	EM + CP⁹	1	0.25–20	119–171	1,2,3,4,5	278 (43)	15.5^b	5.6^b
Turkey age	3-wk-old	1	10–20	125–145	9	23 (8)	8.7^c	5.8^e
	5-wk-old	1	10–20	125–145	9	25 (8)	76.0^d	5.6^e

¹Clostridium perfringens inoculation (0 = no, 1 = yes) status of lesion scored birds, ² Number (in thousands) of inoculated Eimeria meleagrimitis oocysts per bird, ³ number of hours elapsed between Eimeria meleagrimitis inoculation and examination of turkeys, ⁴ Number of bird scored for intestinal lesions (number of pooled samples of intestinal contents examined for OPG), ⁵ Median log₁₀ of oocysts per gram intestinal contents, based on samples of contents from posterior small intestine (from Meckel’s diverticulum to caeco-intestinal junction), caeca and colorectum from Eimeria meleagrimitis-inoculated turkeys, ⁶ Hours elapses between Eimeria meleagrimitis inoculation and examination for intestinal lesions, ⁷ OPG data from experiments 4 and 9, ⁸ Inoculated with Eimeria meleagrimitis, ⁹ Inoculated with Eimeria meleagrimitis and Clostridium perfringens
^a-bDunn’s test with Bonferroni adjustment of p-values for multiple comparisons, ^c-dPearson chi-square test, ^e-fKruskal-Wallis rank test, ^gFisher’s exact test. Different letters indicate significant (p < 0.05) difference

ISSN: 1746-6148