Universidade Federal de Minas Gerais, Escola de Veterinária, Departamento de Medicina Veterinária Preventiva, Laboratório de Bacteriologia AplicadaSusceptibility pattern of 45 Campylobacter spp.isolates – 16 C. jejuni, eight C. coli, and 21 C. fetus isolated from different animal species in Brazil – to twelve antimicrobial agents was determined. All Campylobacter spp. isolates were susceptible to gentamicin, sulfadiazine, and sulfamethoxazole. C. jejuni and C. coli were also sensitive to chloramphenicol, whereas all C. fetus strains were susceptible to kanamycin. Cefoperazone showed the highest percentage of resistance among C. jejuni (68.75%), followed by nalidixic acid (31.25%), ampicillin (37.50%), tetracycline (37.50%), erythromycin (12.50%), and kanamycin (6.25%). Likewise, cefoperazone exhibited the highest percentage of resistance among C. coli (75.00%), followed by nalidixic acid (50.00%), tetracycline (50.00%), erythromycin (37.50%), ampicillin (12.50%), and kanamycin (12.50%). Among C. fetus strains, nalidixic acid showed the highest resistance rate (85.71%), followed by cefoperazone (71.43%), tetracycline (42.86%), ampicillin (19.05%), chloramphenicol (9.52%), and erythromycin (4.76%). Therefore, it was found that the majority of Campylobacter spp. isolated from animals was sensitive to gentamycin, chloramphenicol, kanamacyn, and sulfonamides; however, a high proportion of the strains showed reduced susceptibility to nalidixic acid, ampicillin, cefoperazone, and tetracycline. Moreover, C. coli and C. fetus isolates showed a high percentage of multidrug resistant strains.

Fatty liver is considered a serious problem in broilers as liver is the main organ involved in metabolism of all absorbed substances. In addition, fatty liver has a direct impact on the growth and performance of the chicken. One of the modern approach in controlling metabolic upset, is the use of probiotics, prebiotics in controlling this problems. Here we tried to summarize the protective role of some probiotics, prebiotics and other natural lipotropic factors and their mode of action against hperlipidemia and fatty liver in broilers.

The pharmacokinetic aspects of cephradine were studied after intravenous (IV), intramuscular (IM), subcutaneous (SC) and oral administration of a single dose of 50 mg kg-1 b.wt. in chickens. Tissue distribution and residues of cephradine after repeated oral administration for 5 consecutive days were also estimated. After IV injection of cephradine in a dose of 50 mg kg-1 b.wt., the serum concentration time curves were best described by a two compartment-open model. The drug was rapidly distributed with a distribution half-life (t0.5(α)) of 0.120 h and apparent volume of distribution (Vdss) was 2.187 L kg-1. The drug was rapidly eliminated with a half-life of elimination (t0.5(β)) of 1.047 h and the body clearance (ClB) was 2.35 L kg-1 h-1. The drug was rapidly absorbed after IM, SC and oral administration as indicated by short half-lives of absorption (t0.5(ab)) of 0.154, 0.364 and 0.65 h., respectively. While the elimination half-lives (t0.5(el)) and systemic bioavailabilities were 0.859, 2.652, 1.74 h and 59.386, 84.5, 97.97 %, respectively. Repeated oral administration of cephradine (50 mg kg-1 b.wt twice daily) for 5 consecutive days caused no change in serum enzyme activities of ALT and AST but induced a significant increase in serum uric acid concentration at 72 to 120 hours post administration.

This study aimed to investigate the efficacy of probiotic supplementation in mitigating stress and improving performance, carcass yield, carcass quality parameters, sensory acceptability, microbiological quality and economic profitability of broilers reared at different stocking densities. Two hundred and forty chicks were divided into four groups; two groups were reared at a low stocking density (LSD, 10 bird/m2), including one group that was provided with Protexin® probiotic (Enterococcus faecium) supplemented in water (LSDP). Similarly, the other two groups were reared at a high stocking density (HSD, 15 bird/m2), including one group that was provided with the same probiotic supplementation (HSDP). Throughout the growing cycle, bird performance was monitored. At the end of the growing cycle, stress indicators were measured in blood. Besides, carcass and giblet weights, dressing yield, carcass quality parameters, sensory acceptability, microbiological quality and economic profitability were assessed. As a result, HSD mostly impaired broiler performance, increased stress indicators, reduced carcass yields, carcass quality parameters and sensory acceptability, while boosted profitability and slightly lowered microbiological quality. On the other hand, probiotic supplementation reversed the negative effects of HSD. As probiotic supplementation boosted broiler performance, reduced blood stress indicators, increased carcass and giblet yields, carcass quality parameters and sensory scores, besides, it improved the microbiological status of broiler meat in terms of fecal coliforms and E. coli MPN. To conclude, rearing broilers at high stocking density induced stress, compromised performance and reduced carcass quality. These negative impacts could be successfully faced by using probiotic supplementation in drinking water.

This study was carried out to assess the effects of dietary supplementation of yeast-based Zn, Se, and Cr on growth performance, carcass characteristics, immune response, and histomorphological changes in broiler chickens. A total of 1092 one-day-old unsexed broilers of Ross 308 strain were randomly allocated into two equal treatment groups (6 equal replicates/ group). Birds were fed the dietary treatments from day 1 to day 35 of age. The first group was fed a basal diet without yeast-based Zn, Se and Cr supplementation (control). The second group was fed a basal diet supplemented with 1.5 mg, 0.15 mg and 2 µg / kg diet of Zn, Se, and Cr, respectively. The yeast-based Zn, Se and Cr increased (P<0.05) the growth rate, carcass traits and improved feed conversion ratio compared to control. The antibody titer against avian influenza and the relative weight of bursa, thymus and spleen were increased (P < 0.05) in broilers supplemented with yeast-based Zn, Se, and Cr compared with the control. The intestinal villi height and crypt depth and bursa diameters were increased in broilers fed the yeast-based Zn, Se and Cr supplemented diet. In addition, there was an increase in the lymphocytic infiltration in the bursa and a decrease in germinal centers in the submucosal lymph nodules of the ileum of birds supplemented with yeast-based Zn, Se and Cr compared to the control. In conclusion, dietary supplementation of yeast-based Se, Cr, and Zn in combination could improve growth performance, carcass traits, immune responses and histo-morphological parameters in broiler chickens.

Acute upper respiratory disease in chickens is a major cause of economic losses due to high mortality rates especially in poorly managed cases. Respiratory disease in poultry is initiated by variety of viruses, bacteria and fungi. The current study aims to investigate the prevalence of avian pathogenic E. coli (APEC), their proteases and other virulence genes in respiratory viral disease outbreaks in broiler chickens. Quantitative RT-PCR (qRT-PCR) was performed on samples from 25 farms with respiratory affections, APEC was isolated and virulence determinants in E. coli were investigated phenotypically and genotypically. E. coli was isolated from different flocks (100%, n=25). They were positive to Congo red binding (100%, n=25), iss gene (100%, n=25), iutA gene (92%, n= 23), tsh gene (24%, n=6), vat gene (20%, n=5). Presence of iss gene and CR binding proves that all isolates are APEC. Although the entire 25 APEC isolates carried more than one virulence gene; either 2 genes (n=17), 3 genes (n=7) and 4 genes (n=1), no effect of the number of genes harbored on the mortality rates in different flocks was observed. The presence of two serine proteases genes (tsh and vat) was confirmed in a total of 10 isolates (40% of the isolates) with positivity to tsh gene (24%) and vat gene (20%). qRT-PCR for detection of IBV-S1, AIV-H9, AIV-H5 and velogenic NDV-F genes revealed that 96% (n=24), 44% (n=11), 12% (n=3) and 4% (n=1) of 25 farms were positive to IBV, AIV-H9, velogenic NDV and AIV-H5, respectively. The results showed that among the 25 flocks, single viral infection was observed in 12 flocks (11 IBV and 1 AIV-H9), while mixed viral infections were detected in 13 flocks; IBV/AIV-H9 (n=9), IBV/velogenic NDV (n=3) and IBV/AIV-H9/AIV-H5 (n=1).The average mortality rate was the lowest in flocks infected with IBV, higher rates of mortality were observed in flocks infected with AIV-H9, velogenic NDV and AIV-H5. Flock age seems to affect the mortality rate in flocks infected with AIV-H9 where flocks aging 16:20, 21:25 and 26:30 days suffered from 2.38%, 8.13%, 11.48% average mortality rates, respectively.

Merthiolate (Thiomersal) is known to be used as antimicrobial agent in inactivated vaccines without affecting vaccine potency. The present work investigated the effect of thiomersal contents in ND, AI and IBD inactivated vaccines on liver and kidney functions of vaccinated birds. The histopathological effect and the withdrawal time of such mercurial product from vaccinated chicken muscles were also investigated. Results revealed that residual thiomersal contents in ND, AI and IBD were 0.03; 0.02 and 0.03mg/ml respectively. Liver and kidney function parameters showed significant increases in serum activities of alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) up to the 4th week post vaccination. Serum urea was significantly decreased on the 3rd week in vaccinated birds compared to control ones. Significant increase in serum creatinine in vaccinated chickens was recorded on the 5th week post vaccination. Liver and kidney functions’ parameters remain high allover the experimental period (8 weeks). The histopathological examination of liver specimens revealed degeneration of hepatic cells and congestion of the central vein with inflammatory cell infiltration and congestion of blood vessels as well as coagulative necrosis. The spleen of vaccinated chickens showed depletion of lymphocytes while lungs showed thickening of the alveolar. Mercury contents in muscle were 0.72, 0.52; 0.046 and 0.00 mg/kg on the 1st, 2nd, 3rd and 4th week post last vaccination that considered safe to the consumer. It is recommended that vaccinated poultry with inactivated vaccines containing thiomersal should not be slaughtered before at least 4 weeks and it is preferable to use combined inactivated vaccines to reduce the thiomersal contents as possible.

Three vaccination regimes based on Clostridium perfringens (C. perfringens) type A, C or combined AC toxoids were evaluated to detect if toxoid vaccines can prevent necrtotic enteritis (NE) caused by clostridial infection in broilers. The vaccines were administered two times at two weeks interval, then the birds were challenged with virulent strains of C. perfringens type A, C or combined AC. Blood samples were taken after both first and second vaccination doses as well as after challenge. Evaluating parameters included clinical signs, gross intestinal lesions, hemogram [red blood cell count (RBCs), packed cell volume (PCV), hemoglobin (Hb), total leukocytic count (TLC) and differential leukocytic count],serum biochemical assays [total protein (TP), albumin (Alb), globulin (Glob), albumin globulin ratio (A/G), serum activities of alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP) and uric acid (UA) values] and ELISA test for detecting serum antibody titers. Results revealed that affected birds showed marked depression, anorexia, reluctance to move, ruffled feathers and diarrhea. Numbers of chickens with intestinal lesions in immunized challenged groups were greatly fewer than the infected non immunized ones. There was an increase in RBCs, PCV and Hb. TLC decreased in infected non immunized birds and increased in vaccinated ones. Heterophils were increased in infected groups while, lymphocytes decreased. Prominent lymphocytosis was observed in immunized birds. Results of biochemical assays showed that there was a significant increase in TP, Alb, Glob, ALP, ALT, AST and UA and decrease in A/G. Results of ELISA test showed that there was a significant increase in antibody titer after immunization paricularly after the second dose of vaccination. The combined AC toxoid provided the greater antibody titer and best protection followed by toxoid A and finally toxoid C. We concluded that results provide an evidence that immunization of broilers with toxoid vaccines paricularly the combined type AC is safe, welltolerated and can protect broiler chickens against NE after the second booster dose of the vaccine.

Chicken bones, a by-product of the poultry industry, can directly or indirectly enter the food chain. Bone meal and bone products could be sources of many contaminants. Considering the wide range of uses made of bones in the culinary and food industries, this material needs to be safe and antibiotic residue–free. To determine if such is the case, the concentration of doxycycline in chicken bones was investigated, this antimicrobial being one of the most commonly used in poultry production.

Objective: The purpose of this work was to investigate the combination of early-age acclimation and linseed dietary inclusion in enriching polyunsaturated fatty acids (PUFAs) in broilers meat as a strategy to mitigate heat stress. Materials and Methods: A total of 400 broiler chicks were assigned to four experimental groups with four duplicates (25 animals each): C: control (basal diet), AC: early-age acclimated (basal diet), Cl: fed 5% ground linseed, and Acl: early-age acclimated and fed 5% ground linseed. The lipid and fatty acid contents of different parts (breast, thigh, liver, subcutaneous, and abdominal fat) of broilers were determined. Results: Low levels of lipids and unsaturated fatty acids have been found in the meat of accli¬mated broilers. Higher levels of linolenic acids were noted in Cl thigh meat compared to C (6% vs. 2.68%, respectively). The results showed that oleic and linoleic acids constitute a large part of the PUFAs of different meats. The most elevated levels of monounsaturated fatty acids were recorded in the breast meat of AcL animals. The highest content of omega-3 was recorded in the liver of AcL animals compared to that of C (14.98% vs. 7.8%, respectively). Conclusion: We suggest that the combination of treatments during hot conditions has led to the reversion of the environment-affected variables to accepted values, and yields better ther¬moresistance, PUFA-enriched meat, and safeguard animal health which conferred to birds better solutions to reduce fatigue and hypoxic activities, which induces a considerable consumption of oxygen. [J Adv Vet Anim Res 2021; 8(2.000): 237-245]