Faculty of Veterinary Medicine University of Zagreb
Abstract
In order to asses the predisposing effect of coccidiosis to Necrotic enteritis (NE), an experimental study was conducted in broiler chicken. In the first trial (NE alone), symptoms were noticed from the 4th to 7th days post inoculation (DPI), but no mortality was recorded. In the second trial (NE primed with coccidiosis), 23 % mortality was recorded. Grossly, a maximum intestine lesions score of 2 was recorded on the 6th DPI in the first trial. In the second trial, a maximum intestine lesions score of 3.67 was recorded on the 6th DPI. Microscopically, in the first trial, the birds’ intestines from the 4th to the 7th DPI showed hyperplasia of the villi of the jejunal mucosa. In the second trial, the birds’ intestines from 2nd to 4th DPI showed severe hyperplasia of the villi, and the presence of E. necatrix schizonts within and outside the enterocytes. In the second trial, intestines from 5th to 7th DPI revealed shortening of the villi, diphtheritic pseudomembrane formation and the presence of C. perfringens organisms among the necrotic epithelium. It was concluded that intestinal damage characterised by destruction of crypts cells, as well as villi enterocytes and rupture of blood vessels by schizonts and merozoites of E. necatrix predisposed the chicken to a clinical form of NE to increase the mortality percentage.Pokusno istraživanje u tovnih pilića poduzeto je radi procjene predispozicijskog učinka kokcidioze na pojavu nekrotičnog enteritisa (NE). U prvom pokusu (samo NE), simptomi su bili uočeni od 4. do 7. dana nakon zaražavanja, ali bez uginuća. U drugom pokusu (NE uz prethodnu kokcidiozu) ustanovljen je 23%- tni mortalitet. Najjače patoanatomske promjene (2. stupnja) na crijevima bile su u prvom pokusu opažene 6. dana nakon infekcije. I u drugom pokusu najjače promjene na crijevima (3,67) bile su ustanovljene 6. dana nakon infekcije. U prvom je pokusu mikroskopski bila dokazana hiperplazija crijevnih resica u sluznici jejunuma i to od 4. do 7. dana nakon infekcije. U drugom je pokusu teška hiperplazija crijevnih resica bila dokazana od 2. do 4. dana nakon infekcije. Dokazani su bili i šizonti vrste E. necatrix u enterocitima i izvan njih. U drugom je pokusu bilo zapaženo i skraćenje crijevnih resica od 5. do 7. dana nakon infekcije, zatim difterične pseudomembranozne naslage te prisutnost bakterije C. perfringens u nekrotičnom epitelu. Zaključuje se da oštećenje crijeva uzrokovano šizontima i merozoitima vrste E. necatrix, koje se očitovalo propadanjem stanica crijevnih kripti kao i propadanjem crijevnih resica te prsnućem krvnih žila, djeluje kao predispozicijski čimbenik na kliničku pojavu nekrotičnog enteritisa i povećani mortaltet
