The role of an attenuated anticoccidial vaccine on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis in broiler chickens

Figures & data

Table 1.  Experimental design to evaluate the role of an attenuated anticoccidial vaccine on the intestinal ecosystem and on the pathogenesis of experimental necrotic enteritis in broiler chickens.

Experimental group	Challenge	Vaccination
N	−	−
PN	−	+
M	+	−
PM	+	+

Figure 1.  Gross intestinal, liver and gizzard lesion scoring system in the experiment of anticoccidial vaccination. See Materials and Methods for details of scoring system. Arrows indicate gross lesions.

Table 2.  Number of birds with macroscopic necrotic enteritis lesions according to treatment group and sampling day.

	Experimental group
Sampling day	N	PN	M	PM
21	0	0	5	3
22	0	0	11	7
23	0	0	12	12
24	0	0	11	7
Total	0	0	39	29
Birds with intestinal lesions score greater than one (two or more) were classified as NE-positive.

Table 3.  Gross lesion scores in the intestine, gizzard and liver per treatment group.

	Experimental group
Location	N	PN	M	PM
Intestine^a	0.65±0.48^A	0.50±0.51^A	4.60±2.19^B	3.08±2.35^C
Liver	0.66±0.85^A	0.52±0.85^A	1.25±1.01^B	1.04±1.08^B
Gizzard	0.79±0.93^A	0.54±0.93^A	0.52±0.93^A	0.77±0.93^A
Data presented as mean±standard deviation. Mean values in the same row with a different uppercase superscript letter differ significantly (P≤0.05).

Table 4.  pH and viscosity values of contents in different parts of the intestinal tract, as well as C. perfringens counts in caeca per treatment group.

	Experimental group
Location	N	PN	M	PM
pH
Duodenum	6.12±0.23^A	6.01±0.23^B	5.72±0.46^C*	5.89±0.31^D*
Jejunum	5.97±0.15^A	6.00±0.15^A	5.54±0.54^C	5.83±0.23^B
Ileum	6.94±0.39^A	7.07±0.39^B	5.87±0.93^D	6.46±0.77^C
Caeca	6.00±0.46^A	6.13±0.54^A	6.12±0.46^A	6.20±0.54^A
Viscosity
Jejunum	8.48±4.26^A	8.51±3.41^A	3.23±3.10^B	4.51±3.56^C
Ileum	12.77±6.43^A	15.08±5.34^B	5.60±8.68^C	7.97±11.93^C
Log10 C. perfringens
Caecum	4.36±1.32^A	3.25±2.09^B	6.08±2.17^C	5.18±1.70^D
Data presented as mean±standard deviation. Mean values in the same row with a different uppercase superscript letter differ significantly (P≤0.05 or *P≤0.10).

Table 5.  Overall mean grade of semi-quantitative analysis of C. perfringens counts in the gastrointestinal tract and liver per treatment group.

	Experimental group
Location	N	PN	M	PM
Duodenum	0.47±1.16^A	0.61±1.55^A	2.44±2.17^B	1.56±1.94^C
Jejunum	0.17±0.70^A	0.61±1.31^B	3.17±1.70^C	1.47±1.94^D
Ileum	1.56±2.09^A	1.83±2.25^A	3.86±0.54^B	2.86±1.70^C
Gizzard	0.00±0.00^A	0.08±0.39^A	0.42±0.77^B	0.33±0.70^B
Liver	0.00±0.00^A	0.14±0.70^A	0.36±0.93^B	0.00±0.00^A
Data presented as mean±standard deviation. Mean values in the same row with a different uppercase superscript letter differ significantly (P≤0.05).

Figure 2.  Jejunum cross-section obtained from a 23-day-old broiler chicken, challenged with C. perfringens and E. maxima. Marked inflammatory reaction was observed, which consisted of infiltration of heterophilic granulocytes and lymphocytes. Moreover, the presence of large numbers of rod-shaped bacteria as clusters (2a) or individually (2b) was detected at the intestinal lumen and mucosa (haematoxylin and eosin).

Figure 3.  Jejunum cross-section obtained from a 23-day-old broiler chicken, challenged with C. perfringens and E. maxima. The architectural structure of the intestinal mucosa was lost, while intestinal villi were segmented (3a) or fused (3b) (haematoxylin and eosin).

Figure 4.  Jejunum cross-section obtained from a 23-day-old broiler chicken, challenged with C. perfringens and E. maxima. Aggregation of schizonts as well as infiltration of heterophilic granulocytes and lymphocytes was observed (haematoxylin and eosin).