Abstract
Necrotic enteritis is a severe bacterial infection that affects the intestines of chickens, resulting in significant economic losses. The current investigation aimed to isolate and identify Clostridium perfringens phenotypically and molecularly from 200 distinct diseased field cases. Subsequently, antibiotic sensitivity testing and pathogenicity assessment were conducted on the isolated strain in susceptible birds. Birds were randomly assigned to five groups (15 per group, with triplicates of five birds each) as follows: G1 (negative control; non-infected), G2 (positive control; birds infected with C. perfringens), G3 (birds supplemented with organic acids via drinking water from day one until the end of the experiment and infected with C. perfringens), G4 (birds infected with C. perfringens then supplied after challenge with organic acids in drinking water till the end of experiment), and G5 (birds infected with C. perfringens and treated with 20 % amoxicillin powder for three consecutive days). Chickens were monitored for clinical symptoms, mortality, feed conversion ratio, nutrient transporter gene expression, and histopathological alterations during the trial. Of the 200 samples examined, only 50 were positive for C. perfringens, yielding an incidence of 25 %. The molecular identifications showed the detection of Alpha toxin (100 %) and Beta toxin (20 %), while all isolates were negative for Epsilon and Iota toxin genes. The isolated C. perfringens showed higher resistance to amoxicillin/clavulanic acid (96 %), followed by chloramphenicol, ampicillin/sulbactam, tetracycline, and ceftriaxone with 88 %, 86 %, 78 %, and 72 %, respectively. However, lower susceptibility was recorded for metronidazole (64 %) and clindamycin (66 %). G3 birds showed a significantly (P<0.05) lower colonization rate by C. perfringens, a significantly (P<0.05) higher final body weight, and a lower feed conversion ratio compared to the other groups. By comparing gene expression in G1 with G3, G4, and G5, upregulation was observed in all three groups. GLUT1, CAT1, and SGLT1 showed higher levels in G4 than in G5. A significantly higher (P<0.05) up-regulation was observed in G3 than in G4 and G5. It may be concluded that organic acids serve as an effective antibiotic alternative to reduce C. perfringens colonization, promote growth, boost nutrient transporter gene expression, and improve intestinal histomorphometry in broilers infected with C. perfringens.