The effect of 10 times (10x) overdose of enrofloxacin was studied in broiler chickens. One hundred and eighty chicks were classified in 3 equal groups. The first group received normal theurapeutic dose of enrofloxacin (1x) in drinking water for the first 5 consecutive days of age and repeated again at 24th -28th day of age. The second group received 10x (overdose) at the same ages. The third group was left non-medicated as a control group. Blood samples were taken on the 6th, 14th, 29th and 34th day of age for different laboratory tests. Enrofloxacin at 10x caused a decrease in the value of the following parameters: HI antibody titers to NDV vaccine at the 14th and the 34th day of age, serum albumin at the 10th day of age, hemoglobin at the 29th and the 34th day, lymphocytic count and IBDV ELISA titers at 29th day of age, uric acid at 29th day, phagocytic activity at 34th day, Lactobacillus spp. count in duodenum, feed conversion efficiency and body weight gain. The 10x (overdose) increased serum urea and creatinine at 29th day of age, serum AST and ALT at 29th and 34th day of age, and heterophilic count. Histopathological degeneration in liver, spleen, kidneys, bursa of Fabricius and thymus were demonstrated by 10x (overdose) of enrofloxacin. Challenge with vNDV caused 66.6% mortality in birds received the 10x (overdose) compared with 33.3% in the vaccinated non treated control group.

This study was done to investigate the prevalence of the Enterobacteriaceae in chickens and eggs. Isolation of forty four different bacterial isolates belonging to Enterobacteriaceae from chicken egg samples, cloacal swabs and swabs from Hatcheries’s floor, the isolates from commercial flock swabs were biochemically identified as E coli, P. mirabilis E Sakazakii and E .cloacae by incidence 22%, 55 %, 11% and 11 % respectively. The isolates from Layers and broilers breeder cloacal swabs were biochemically identified to be E. coli, P. mirabilis E. fergusonii and E .cloacae by incidence 20 %, 20 %, 20% and 40 % respectively. The isolates from commercial eggs were biochemically identified to be Pantoea Sp. , Kluyvera sp., E Sakazakii , E.aerogenes and E.harmanii by incidence 33.3% , 16.6% , 16.6% , 16.6% and 16.6 % respectively. The isolates from fertilized egg samples were biochemically identified as E Sakazakii , E. fergusonii , E.coli , E. Cloacae , Aeromonas ,S. Anatum and Prov. Alcolifaciens with a number of 1 ,1, 3, 3, 2, 2 and 1 , incidence 8% , 8% , 23% , 23% , 15% , 15% and 8 % respectively. The incidence of Enterobacteriaceae isolates from floor swabs of both primitive and automatic hatcheries was 20.8 % and these isolates were biochemically identified to be Pantoea spp., Citrokoserilama, k.pneumo. Ozaenae and E .cloacae with number 2, 1, 1 and 1 also its incidence were 40%, 20%, 20% and 20 % respectively. We found that the most common isolated bacterium from eggs either fertilized orcommercial table eggs in our study was E.coli although we could isolate other bacterial species as Enterobacter, Proteus species , Escherichia fergusonii; E. Sakazakii, Klebsiella sp., S. anatum, and Pseudomonas sp..In-vitro sensitivity test of the isolated strains to various chemotherapeutic agents revealed that all isolates were sensitive to Ciprofloxacin, Enrofloxacin, and Amoxicillin.

Four groups of one-day-old SPF chicks were inoculated with the four IBV variants at 1 day old to study the virulence of these isolates. The results at 2 weeks post infection (PI) revealed that all isolates were able to induce serological resposne postinfection, respiratory distress and depression. 20% and 100% mortalities were recorded with isolates 4 and 23; respectively. Assessment of pathogenicity index and pathotyping (at the end of observation period “2wk-PI”), categorized the 4 tested isoaltes (4, 16,18, 23) into three isoaltes of high virulence (4, 18 and 23), and one isolate of intermediate virulence (16). About 50% reduction in body weight was recorded with the four IBV isolates 2 wk PI. Kidney lesions were nephritis-nephrosis with urate deposition in ureters, while microscopic lesions were associated with increase in the amount of rough endoplasmic reticulum (RER). Tracheal lesions recorded as increase the amount of mucin, while microscopic lesions were edema of mucosa and inflammatory cells in the lamina propria. The regime of administering the infectious bronchitis (IB) live commercial H120 vaccine at 1 day old SPF chicks, and the heterologous challenge with four variants (serotypes) at 4 weeks of age, was found to be poorly effective in protecting the respiratory tract of SPF chickens with protection percentages of 8.1%, 55%, 10.5% and 12.6% corresponding to field isolates of IBV 4, 16, 18 and 23; respectively. Protection was measured by assessing ciliary activity of the tracheal epithelium following challenge. It is suggested that the use of the live IB-H120 vaccine will not always broaden the protection against challenge with IB multiple serotypes isolated from Egypt. Therefore it is necessary to develop a new IB vaccines, either locally prepared or imported to overcome any new IB serotype that were emerged, through modifying vaccination strategies to make them appropriate to the field situation.

In this study, a combined Trivalent vaccine against ND, IB and M. gallisepticum was locally prepared and evaluated in comparison with other locally prepared Bivalent ND and IB and monovalent M. gallisepticum vaccines. The obtained results were promising for this locally prepared Trivalent vaccine and the immune response was outstanding starting at the 2nd week post vaccination and showed extended raising allover the experiment period. The immune response of chickens vaccinated with the Trivalent was shoot up post boostering at the 8th week post 1st vaccination. These results were confirmed and supported by the challenge tests using the virulent strains of the three pathogens. So it could be recommend that the production of this Trivalent ND, IB and M. gallisepticum will help in the control of the three diseases and their complications.

The present study was conducted to determine the effect of salinomycin at a concentration 60 and 120 ppm alone and with vitamin E or selenium on haematological and biochemical parameters and histopathological changes of the treated chicken. Salinomycin (120 ppm) induced decrease in body weight, feed consumption and feed conversion efficiency. In addition, when salinomycin (120 ppm) given with vitamin E, the body performance improved significantly, but when sodium selenite used, body performance significantly decreased. Salinomycin at concentration 120 ppm induced decrease in blood parameters (RBCs count, TLC count, Hb content and PCV %). Concurrent use of vitamin E with salinomycin leads to improvement of these parameters. Salinomycin at 120 ppm induced significant increase in enzymes activities (ALT and AST). The uses of vitamin E with slinomycin (120 ppm) caused significant decrease in these activities. In contrast to selenium, which reduce the activity of AST enzyme only. Salinomycin at 120 ppm decreased the total protein concentration and increased the level of creatinine and uric acid. Concurrent administrations of vitamin E or selenium with salinomycin have no effect on these parameters. At 120 ppm salinomycin, selenium increased the creatinine concentration in blood serum. The drug at 60 or 120 ppm induced various pathological changes in certain tissues (liver, heart, kidney and skeletal muscle) ranged from degeneration to necrosis of these tissues. Concurrent administration of salinomycin with vitamin E or selenium revealed that vitamin E decreased the pathological changes of studied tissues.

This study was conducted to investigate the efficacy of the Newcastle disease (ND) live vaccines from different commercial sources used in different programs for vaccination of chicks having maternal antibodies against Mycoplasma infection. The immune response was estimated using HI and challenge tests. The effect on the chicken performance was estimated by the detection of the body weight gain. The role of vaccines in stimulating respiratory bacterial stress was pointed out by the lesion scores. Birds vaccinated with live vaccines from source (2) showed higher HI titers than those vaccinated with vaccine from source (1) and birds received the 2nd vaccination from heterologous source showed lower titers than those received from homologous source. Results of the challenge test indicated that birds vaccinated with live ND vaccines from one source and those vaccinated with Hitchner B1 at 33-days of age instead of La Sota showed 100% protection rate as compared with 95 % followed by vaccination with heterologous La Sota. Birdsreceived Hitchner B1 of vaccine source (1) showed only 85% protection rate. All vaccinated chicken groups showed feed conversion rates lower than the non-vaccinated control one. Groups received Hitchner B1 as a 3rd dose of the vaccine showed higher rates than those vaccinated with La Sota. Results of the lesion score for chronic respiratory disease (CRD) in vaccinated groups with different regimes revealed that birds received ND vaccinal strains from source (1) having higher scores than those received ND vaccines from the 2nd source. Administration of Hitchner B1 vaccine at 33-days of age showed lower scores. Hitchner B1 can be recommended in vaccination of chickens derived from Mycoplasma infected hens.

This study was done to evaluate susceptibility, protective titer level of maternal derived antibodies(MDAbs) of different chicken breed against virulent Infectious bursal disease virus (IBDV) local isolate Fy97 and prediction the optimal time for vacction. All breeds were experimentally infected orally with IBDV isolate Fy97 every 5 days following detection of MDAbs by ELISA. Clinical signs, mortality, lesions and Bursal Histopathology and lesion score were taken as criteria for comparison. Morbidity rates were observed as ≥ 30% in Fayoumi and Dandrawi infected at 15 days of age and in Senawi and Baladi and Lohmann at 20 days of age All breeds showed clinical sings of infection at 30-35 days of age where Senawi breed showed the highest values (65and 70%) followed by Fayoumi (55 and 55%), Dandrawi (50%), Baladi (55-45%) and Lohmann (50-45%). Mortality rates due to IBD infection varied from 0 to 35% in respective to age, in Fayoumi and Lohmann breeds where maximum 35 and 40% occurred at 30 day of age; respectively .Mortality in Dandrawi and Senawi varied from 5 to 40% and pass in close manner at all intervals with the highest value at 30 days of age while Baladi chicks showed same values but lower only at 20 and 25 days. Mean lesion scores in Fayoumi were the lowest at all intervals followed by Lohmann, Senawi, Baladi and Dandrawi. Results of ELISA titers at time of infection showed that Senawi chicks having the highest titers followed by Lohmann, Baladi, Dandrawi and Fayoumi at most intervals. So it necessitates more clarification of the causes of these phenomena and the role of genetics in protection against IBDV infection.

A total of 90 one-day-old male broiler chicks were fed on balanced ration for 15 days and then divided into 3 equal groups. Control group fed ration probiotic free, group 2 and 3 fed ration supplemented with probiotic at concentration levels 0.5 and 1.0g/kg ration respectively for 4 weeks.It was found that probiotic improve body weight gain and feed conversion ratio. Relative organs weights were not altered in groups of birds fed ration mixed with probiotic. Serum values of biochemical parameter (AST, ALT, ALP, total protein, A/G ratio, Ph) were not significantly changed in comparison to control group. Probiotic enhance the immune response of broiler chickens in a dose dependent relation as documented by increasing the serumNDHI antibody geometric mean titres to ND vaccine, phagocyte percentage and phagocytic index of peripheral blood monocyte of broiler chickens. We concluded that probiotic composed of 3 strains of bacteria (Pediococcus acidilactici, Pediococaoccus pentosaceus and Bacillus Amylolique- faciens) in addition to 2 strains of yeast( Pichia farinose and Dekera anomala ) enhance body weight gain, feed conversion, growth performance and Newcastle disease antibody titres in broiler chickens. Moreover, probiotic was safe as proved by serum biochemical profile and relative organ weight of male broiler chickens.

In 9 weeks field study, a total of 14100 (Ross broiler breeders) 51 weeks-old chickens fed on the same ration, placed in 2 houses (6600 female + 450 male / house). Birds of house 1 were treated with antimycotoxin adsorbent aluminum silicate (G-V-tox®) 5 kgm/ ton, while those of house 2 were kept as non treated controls. Productivity and reproductivety parameters were calculated for comparison. Treated flock showed improved average egg production (Average 62.2%/week) compared with non treated (Average 61.7%/week), but all still lower than farm stander (Average 76.4%/week). Marked improvement was in the 1st 3 weeks (51-53) of treatment only. Total 9 weeks production declined was 5.5% and 8.4% in control and silicate treated flock; with weekly average of 0.61, and 0.93; respectively. Control flock was slower in decline of production (0.61%/week) than treated flock (0.93%/week). Average weekly egg production and hatching eggs/ hen in treated flock was lower than standard and higher than non treated. Hatchery parameters of treated were improved in treated at the first 3 weeks post treatment. The fertility was higher in aluminum silicate treated group (77.2%), than the untreated one (72.19%). The hatchability was in silicate treated (63.66%) versus (62.25%) in the untreated control. Culls % in hatched chicks was 1.91% in treated flock and lower than in non treated (2.85%). Difference percentage between fertility and hatchability of G.V. tox treated chickens was (10.84%) higher than untreated control (16%). The number of marketable chicks l100 was also improved in treated than non treated. In conclusion, our field study cleared that administration of Silicate in ration for treatment of broiler breeders resulted in an improved production and hatchery performance as compared with non medicated control. However; it did not restore it to the farm stander. Consequently the results indicated that we still in need for more effective products to be used to control mycotoxins in breeder chicken.

The pharmacokinetic profile and some pharmacodynamic aspects of cefquinome were studied after intramuscular (IM) and subcutaneous (SC) administration of a single dose of 2 mg kg-1 b.wt. in chickens. Tissue distribution and residues of cefquinome after repeated IM injection for 5 consecutive days were also estimated. Cefquinome was rapidly absorbed after IM and SC injection as indicated by short half-lives of absorption (t0.s(ab)) of 0.170 and 0.262 h., respectively, while the elimination half-lives (t05(el)) were 3.428 and 25.023 h., respectively. Repeated IM doses of cefquinome (2 mg kg-1 b.wt., once daily) for 5 consecutive days caused no change in serum enzyme activities of ALT and AST, but induced significant increase in serum uric acid concentration after 72 to 120 hours of administration. The withdrawal time of cefquinome from tissue of chickens is 5 days following the last dose. Cefquinome has a wide spectrum of activity against Esherchia coli, Proteus mirabilis and Pseudomonas aeroginosa.