One to 42-d-old (432) female broilers were fed different levels of inorganic selenium (ISe) and organic selenium (OSe), according to the following treatments: (1) 0.3 mg ISe; (2) 0.3 mg ISe + 0.2 mg OSe; (3) 0.5 mg ISe and (4) 0.3 mg OSe/ kg of feed. All birds were vaccinated against infectious bursal disease (IBD) at 19d of age and three birds/replicate (R) were inoculated with sheep red blood cells (SRBC) at 32d. Three other birds/R received Freund's adjuvant at 37d and avian tuberculin (AT) in the wattle at 47d of age. All birds were submitted to heat stress after 21d. Performance parameters, bursa and spleen weights, lymphocyte bursa depletion, antibody (Ab) production against IBD and SRBC, hematocrit, leukocytes, heterophil/lymphocyte ratio (H/L), and cellular reaction to AT were evaluated. The contrast analysis showed that OSe has improved feed intake (FI) between day 1 and 42 (p<0.10). Birds fed ISe presented worse H/L ratio (p<0.10), but higher Ab titers against IBD (p<0.04) and SRBC (p<0.05) than birds fed OSe, but OSe supplemented birds showed lower lymphocyte depletion scores in the bursa. The higher FI promoted by OSe may be beneficial when rearing broilers in hot weather. The use of ISe induced higher humoral immune respons
Chicks infected during the first two weeks of life with chicken anaemia virus (CAV) manifest clinical disease that can be avoided if the breeder hens transfer enough antibodies to their progeny. The objective of the present work was to establish the prevalence and titer of anti-CAV antibodies in some Brazilian broiler hen breeder flocks and verify in which phase of life the birds were infected. A total of 1,709 serum samples from 12 broiler hen flocks vaccinated against CAV and 64 unvaccinated flocks were analyzed for CAV antibodies with an enzyme-linked immunosorbent assay (ELISA). All non-vaccinated breeder flocks were found to be infected with CAV, with 89% of the hens tested presenting antibodies, 52% of these with titers considered high enough to protect their progeny against CAV infection. Likewise, all vaccinated hens had antibody titer to CAV capable of conferring protection to their progeny. Thus, vaccination of hens seems capable of conferring protection to chicks against clinically apparent CAV-associated disease.
The aim of this study was to compare a polymerase chain reaction (PCR) method combined with selective enrichment in Rappaport-Vassiliadis broth (PCR-RVB) with standard microbiological techniques (SMT) for the generic detection of Salmonella in samples of porcine origin. Two hundred sixty eight field samples consisting of 42 sets of pooled porcine mandibular lymph nodes and tonsils, 44 samples of intestinal content, 38 pork sausage meat samples and 144 samples of feed collected from swine farms were submitted to the PCR-RVB and SMT protocols. Salmonella was detected in 54 samples using the PCR-RVB assay and in 42 samples by SMT, three of the SMT Salmonella-positive samples (one each of S. Derby, S. Panama and S. Typhimurium) being Salmonella-negative by PCR-RVB. For the PCR-RVB method 15 Salmonella-positive samples were negative by SMT, a significant difference according to the Mac Nemar's chi-squared test (p=0.0153). Subsequent serological typing of the SMT isolates showed the following Salmonella serovars, the number of positive samples being given in parentheses: Typhimurium (12); Bredeney (10); Panama (5); Saint-paul (5); Minnesota (3); Mbandaka (2); Derby (1); Enteritidis (1); Orion (1) and Salmonella sp. (2). We concluded that, although the use of both PCR-RVB and SMT increased the number of positive samples, the PCR-RVB, due to its higher sensitivity and greater speed in giving results, can be implemented to detect Salmonella in samples of porcine origin.
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