Pathological changes and antigen localization in the small intestine of rabbits infected with Eimeria magna

Abstract

<p>Coccidiosis is a major disease caused by various <em>Eimeria</em> species in rabbits. The aim of the present study was to investigate the haematological and pathological changes in rabbits infected with <em>E. magna</em>. Moreover, the localisation of coccidial antigens was examined in the intestines of rabbits with two kinds of serum as primary antibodies. In the present study, forty-five 28-day-old weaned rabbits were randomly divided into three groups and reared in three separate places. Group A was infected with 20×10<sup>3</sup> sporulated oocysts of <em>E. magna</em>, group B was only used to produce anti-<em>E. intestinalis</em> serum by infecting them with 3×10<sup>3</sup> sporulated oocysts of <em>E. intestinalis</em>, and group C was designated as the control group. According to histopathological evaluation of group A, the epithelial cells of the jejunum and ileum were parasitised with a large number of oocysts and other stages of <em>E. magna</em>. The haematological results showed that red blood cell counts, haemoglobin counts, haematocrit levels and the percentage of lymphocytes were significantly decreased in group A compared with group C (<em>P</em><0.01), but white blood cell counts and the percentage of neutrophils were significantly increased (<em>P</em><0.01). The weight of group A began to decrease on the 5<sup>th</sup> day after infection, and this decrease continued until the 9th day. Immunohistochemistry staining revealed that two kinds of coccidial antigens were basically located at the same sites of the intestine when anti-<em>E. intestinalis</em> serum and anti-<em>E. magna</em> serum were used as primary antibodies. Most likely, <em>E. magna</em> and <em>E. intestinalis</em> antigens have some similar antigenic determinants; this finding provides a theoretical basis for screening for common antigens of these two coccidian species.</p>

Alterations in the jejunal microbiota and fecal metabolite profiles of rabbits infected with Eimeria intestinalis

“…The steps for IHC staining were previously described [ 19 ] and are briefly listed below. Sections were incubated with 3% H 2 O 2 for 10 min to block endogenous peroxidase activity and were then incubated with normal goat serum as a blocking reagent for 30 min.…”

Changes of oxidant-antioxidant parameters in small intestines from rabbits infected with E. intestinalis and E. magna

“…The rabbits (n=18) that met the requirements were randomly divided into three groups with six rabbits per group: the first group infected with 3×10 3 E. intestinalis oocysts (Coudert et al, 1993), the second group infected with 20×10 3 E. magna oocysts (Tao et al, 2017), and the third group injected with the same volume of phosphate buffered saline as the first two groups, which was regarded as the control group. After the 8 th day of infection (Yuan et al, 2021), all three groups of rabbits were euthanised and the abdominal cavity was then dissected to quickly collect fresh small intestinal tissues (including duodenum, jejunum and ileum). Subsequently, 200 mg of each intestinal tissue was added to a sterile tube containing 1.8 mL normal saline and ground in a tissue grinder (Wuhan Servicebio Technology Co., Ltd), then centrifuged at 2000 rpm for 10 min, and the supernatant was collected and stored in a refrigerator at -20°C for antioxidant index detection.…”