ABSTRACT:This study investigated an outbreak of inclusion body hepatitis in ROSS 308 hybrid broiler type chickens between 19 and 25 days of fattening. For this purpose, clinical observation, ELISA fowl adenovirus and chicken anaemia virus antibody detection in serum at 21 and 42 days, mortality evaluation, epidemiological analysis, histology and genetic identification were performed. The six flocks of the farm consisted of 90,000 chickens. Only one flock of 15,000 chickens was affected on this farm. At 19 days of age, ill chickens showed clinical signs of depression, anorexia, somnolence, ruffled feathers, anaemic comb and wattles and occasionally nervous signs. Based on ELISA titres, the antibody response to fowl adenovirus increased greatly from 21 to 42 days. The antibody response to vaccination against infectious bursal disease virus and chicken anaemia virus was at the expected level in all broiler flocks. Necropsy showed diffuse petechial and ecchymotic haemorrhages in skeletal muscles, liver, pancreas, kidney, together with hepatomegaly, splenomegaly and catarrhal enteritis. Histologically, fatty liver degeneration, multifocal liver necrosis and intranuclear inclusions in hepatocytes, as well as focal necrosis in pancreas and spleen parenchyma were seen. The DNA of AAV-1 (avian adenovirus group 1) was detected using the PCR method in paraffin-embedded liver samples. The results revealed no association of inclusion body hepatitis with infectious bursal disease virus or chicken anaemia virus infection, and suggested primary disease. However, the involvement of only one chicken flock on the farm remains unexplained.

This study investigated an adenovirus infection in two consecutive breeding flocks in the same poultry hall. Thirty-six thousand one-day-old chickens of the ROSS 308 hybrid broiler type were kept together in one hall. The chickens in the first breeding flock during fattening did not show any clinical signs of the disease or increased mortality. Typical clinical signs of the adenovirus infection were seen in the second breeding flock. The signs included: depression, apathy, somnolence, a crouched position with a droopy head, fuzzy feathers, anaemic combs and wattles, sporadic nervous signs, and reduced weight gain. Increased mortality was recorded from 18 to 25 days of age, the higher mortality rate resulted from dehydration and exhaustion. The surviving chickens showed growth slightly below average by the end of the fattening period. The necropsies of the chickens in the first flock showed characteristic lesions for inclusion body hepatitis (IBH). Adenoviral gizzard erosions (AGE) were found mainly in the chickens of the second consecutive breeding flock. In both breeding flocks, FAdV-A was detected by polymerase chain reaction (PCR) in the liver and gizzard samples. The presence of fowl adenovirus B was not confirmed in the evaluated samples. The results showed lesions in the first flock typical for IBH, whereas the pathological changes in the second flock were characteristic of AGE.

The effects of Lacto-Immuno-Vital synbiotic preparation on gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum and on BW gain in broiler chickens were studied. A flock of 64,400 1-day-old Hybrid ROSS 308 chickens was inducted in the 42-day experiment. The chickens were divided into 2 equally size groups in separate halls. The chickens in the experimental ( E ) group received 500 g of Lacto-Immuno-Vital in 1,000 L of drinking water. The preparation was administered daily from the first day (day 1) to day 7 of the experiment. From day 7 to day 22, it was given in pulsed manner (every third day) at a dose of 300 g in 1,000 L of drinking water. The broiler chickens in the E group gained more weight ( P < 0.001) compared with control from day 10 to day 42. Death of animals during feeding period was 1,078 chickens in the E group compared with 1,115 dead chickens in the control group. Feed conversion ratio was 1.61 kg of supplemented diet/kg of BW in the E group compare with 1.67 kg of nonsupplemented diet/kg of BW in control. The relative expression of IgA gene in the jejunum was upregulated on day 22 in the E group compared with control ( P < 0.05), whereas relative expression of MUC-2 gene was upregulated in the E group compared with control on day 8 and day 22 ( P < 0.05; P < 0.001). Similarly, relative expression of IGF-2 gene was upregulated in the E group compared with control on both samplings ( P < 0.01). The composition of Lacto-Immuno-Vital synbiotic preparation showed beneficial effects on growth performance, feed conversion ratio, morbidity, mortality, and selected parameters of mucosal immunity in the chicken jejunum.