Ileal diverticulitis is a rarely reported condition in poultry. Diverticulum of ileum was noticed in a 4 weeks old male Aseel chick, out of 16622 carcasses of chickens of different lines/breeds necropsied and screened for gut lesions for a period of one year. The chick had stunted growth. The diverticulum was present at mid ileum at its mesenteric surface with 0.5 cm long patent stalk and a distal blind sac of 5cm diameter engorged with gas and semisolid brownish contents. Histologically the sac wall was composed of from outer to inner; serosal lining, oedematous muscle layer, cornified epithelium and diphtheritic membrane with scattered areas of inflammatory cells composed heterophils and lymphocytes. The diverticulum may be an acquired type which got inflamed and affected the development of the chick. This is a first report of ileal diverticulum in a native chicken like Aseel.
Intestinal abnormalities are rare findings in chicken. A few of the previous reports of intestinal malformations were on duplication of ileum in babcock pullet (Gurdev et al., 1976), intestinal diverticulum in white leghorn (Balachandran et al., 1991), duplicated lower intestine (Dhoke et al., 1995) and ileal diverticulum (Wojnarowicz and Olkowski,2005) in broiler chicks. The present study reports ileal diverticulitis in a 4 week old male Aseel chick. Aseel is a native chicken breed of southern states of India, popular for chicken fighting games in the region.
Materials and Methods
The carcasses from the farms of ICAR-Directorate of Poultry Research, Rajendrangar were screened for gut lesions on daily basis. The intestinal diverticulum was noticed in a 4 week old male Aseel chick with stunted growth. Detailed necropsy was conducted and lesions recorded. Sections of the intestine and diverticulum were cut and fixed in 10% neutral buffered formalin and routinely processed, wax mounted, cut at 4 micron thickness and stained using haematoxylin and eosin.
Results and Discussion
A total of 16622 chicken carcasses were screened for gut lesions. The chickens necropsied included exotic and synthetic breeds/lines like Cornish(1675 numbers), Delham Red(3718), White Leghorn(2082), Punjab Broilers (2851), Vanaraja (3190), Gramasree male line(1632) and native breeds like Aseel (342), Nicobari (321), Naked Neck (257) and Ghagus (331). During the screening a 4 week old male Aseel chick was found with distended abdomen and gross stunted growth. On opening the carcass an engorged cyst like structure was evident on the right side of the abdomen, occupying a major portion of the abdomen. On detailed examination the structure was found to be a diverticulum attaching to the middle of the ileum at its mesenteric part, nearly half way from the Meckel’s diverticulum and ileo-caecal junction (Fig.1). Mesenteric part and serosa of the ileum could be seen grossly continuing with the diverticulum with the congested blood vessels. Other segments of the intestine were grossly normal.
Fig1: Gross appearance of digestive tract of a 4 week old Aseel chick. Engorged diverticulum in the mesenteric side of the ileum (thick arrow).Atrophied Meckel’s diverticulum in the anti-mesenteric side can be seen (thin arrow).
The diverticulum had 0.5cm long patent stalk and a distal engorged blind sac. Lumen of the stalk was continuing with lumen of the ileum (Fig.2). The sac had 5cm diameter and was distended with gas and brownish semisolid contents. The inner wall of the sac was lined with loosely attached yellow coloured leathery diphtheritic membrane.
Histologically the diverticulum wall had outer serosa, middle oedematous and atrophied muscular layer, inner cornified epithelium and diphtheritic membrane (Fig.3). Diphtheritic membrane was detached from the epithelial layer in most of the areas. The diphtheritic membrane contained heterophils and necrotised cell debris. The normal mucosa and muscularis mucosa of the intestine were absent in the diverticular wall.
Fig 3: Cross section of the diverticulum sac. Cornified epithelium (thin arrow), edematous muscular tissue (thick arrow) with congested blood vessels. Detached necrotic lining membrane (star) can also be seen (H&E, 100 x)
Blood vessels were engorged in the muscular layer. Scattered areas of inflammatory cells composed of heterophils, plasmacytes and lymphocytes were evident in the muscular layer towards the mucosa (Fig.4).
Absence of normal intestinal mucosal and muscularis mucosal layer differentiates the diverticulum of the present case from the duplication of ileum or caecum as reported by some authors (Pizarro et al., 1994; Ahangaran et al., 2012). Keratinisation of the internal layer of the diverticulum may be as a result of persistent pressure developed in the diverticulum. Stunting of the bird may be an after effect of pressure development in the abdomen by the enlarging diverticulum. The actual cause for the development of the diverticulum is not known. Congenital diverticula like Meckel’s diverticulum occur at anti-mesenteric surface, while acquired type of diverticula mostly occur in the mesenteric surface (Ablin et al., 1991).The mesenteric position of the diverticulum in the present case point out the possibility of development of the diverticulum as acquired type. Pre-existing weakness of structural wall of the intestine was attributed as a possible cause of development of such diverticulum by some workers (Wojnarowicz and Olkowski, 2005). Interestingly middle of ileum can be seen as the common site of development of intestinal anomalies in chicken in the present study and most of the above sited reported cases. The common position need to be further explored for arriving at a conclusion for exact cause of development of the anomaly.
The authors are grateful to the Director, ICAR-Directorate of Poultry Research, Rajendranagar, Hyderabad for providing the facilities for conducting the study.