1. An experiment was conducted to compare the natural resistance of an indigenous breed of local village chickens to Salmonella gallinarum with two commercial breeds: ISA Brown and ISA White layers under experimental conditions.
2. A total of 72 chickens from each of these breeds were randomly distributed to 4 pens to provide equal numbers of two replicate pens maintained as infected and control (uninfected). All chickens in infected groups were inoculated orally with 1 × 108 CFU (1 ml dose) of a field isolate of S. gallinarum, at the age of 8 and 16 weeks given over 5 consecutive days. Growth performance, clinical signs, gross pathological lesions and antibody responses were measured.
3. A significantly higher mortality was observed in the brown layers compared with the white layers, and clinical signs and mortality were absent in village chickens. However, a large number of birds with gross lesions and high antibody titres were detected in village chickens, indicating that birds had the disease subclinically. Commercial breeds had a significantly higher body weight, feed intake and feed conversion efficiency.
4. There was a significantly lower proportion of positive reactors in village chickens in the whole-blood agglutination test (35%) compared to brown (100%) and white (90%) layers even after the second inoculation. Uninfected birds were negative in all groups. The indirect enzyme-linked immunosorbent assay confirmed these observations.
5. These results suggest that the indigenous breed had superior natural resistance to S. gallinarum than the commercial breeds. 相似文献
The study aimed to investigate the effect of feed supplements, viz Lactobacillus plantarum LGFCP4 (laboratory isolate from GIT of Guinea fowl), Lactobacillus acidophilus (NCDC, Karnal) and in‐feed antibiotic bacitracin methylene disalicylate (BMD) on growth performance, FCR, carcass traits and immune organs weight, intestinal histomorphometry and gastrointestinal microflora population in broiler chickens. In a completely randomized design, CARIBRO‐Dhanraja broiler chicks (n = 160) were used with four treatment groups. During the entire experimental duration of 35 days, treatment groups were provided with different dietary treatments (T1 – basal diet (negative control), T2 – antibiotic growth promoter BMD 20 g/100 kg feed (positive control), T3 – 1 × 108 cfu of L. acidophilus/gm‐fermented feed +MOS 1 g/kg feed and T4 – 1 × 108 cfu of laboratory‐isolated L. plantarum LGFCP4/gm‐fermented feed+ MOS 1 g/kg feed. After 35 days of experimental period, no significant results have been observed in different growth performance traits among treatment groups. Cut‐up parts and edible organs' weight remained unaffected by dietary supplementation, whereas weight of immune organs were significantly higher (p < 0.05) in L. plantarum LGFCP4‐supplemented group. At the end of feeding trial, significantly (p < 0.05) lower E. coli count was observed in crop of T4 birds, while in ileum, T2 and T3 showed lower count. In caeca, T2 group showed lowest E. coli count. Salmonella count in crop and ileum was significantly (p < 0.05) low in T3 and T4, while in caeca, T2 group showed lowest count. In terms of histomorphometry, duodenal villous height (VH), crypt depth (CD) and VH:CD ratio were higher for T3 and T4 and lowest values were obtained for T2 group. The results of the study showed that L. plantarum LGFCP4 isolated from GIT of guinea fowl can effectively replace in‐feed antibiotic growth promoters in broiler diets by altering intestinal villi morphology and improving the gut health by reducing the pathogenic microbial load. 相似文献
The Swedish control program for salmonella includes restrictions and on-farm control measures when salmonella is detected in a herd. Required control measures are subsidised by the government. This provides an opportunity to study costs for on-farm salmonella control. The aim of this study was to describe the costs for on-farm salmonella control in Swedish cattle herds and to investigate the effects of herd factors on these costs in dairy herds.
Results
During the 15 years studied there had been a total of 124 restriction periods in 118 cattle herds; 89 dairy herds, 28 specialised fattening herds and three suckler herds. The average costs per herd for on-farm salmonella control was 4.60 million SEK with a median of 1.06 million SEK corresponding to approximately 490 000 and 110 000 EUR. The range was 0.01 to 41 million SEK corresponding to 1080 EUR to 4.44 million EUR per farm. The costs cover measures required in herd-specific control plans, generally measures improving herd hygiene. A mixed linear model was used to investigate associations between herd factors and costs for on-farm salmonella control in dairy herds. Herd size and length of the restriction period were both significantly associated with costs for on-farm control of salmonella with larger herds and longer periods of restrictions leading to higher costs. Serotype detected and administrative changes in the Swedish Board of Agriculture aiming at reducing costs were not associated with costs for on-farm salmonella control.
Conclusions
On-farm control of salmonella in Swedish cattle herds incurred high costs but the costs also varied largely between herds. Larger herds and longer restriction periods increased the costs for on-farm control of salmonella in Swedish dairy herds. This causes concern for future costs for the Swedish salmonella control program as herd sizes are increasing. 相似文献
To investigate the situations of predominant strain and antibiotic resistance of pathogenic Salmonella from chickens in Guangxi Zhuang Autonomous region, Salmonella was pre-enriched and isolated from tissues of clinical suspected chickens, and the Salmonella isolates were identified by biochemical test using ID 32E System for the identification of Enterobacteriaceae of VITEK System ATB Expression, serotypes were determined by slid agglutination test, antibiotic susceptibility was analyzed by ATB VET Susceptibility Test Strip of Enterobacteriaceae antibiotics.The results showed that 34 Salmonella strains were obtained from 310 clinical samples, of which 1 strain belonged to A serogroup, 1 to C2 serogroup, 15 to B serogroup, 14 to D serogroup and 3 to untyped serogroup, and S.typhimurium of B serogroup and S.pullorum of D serogroup were the predominant serotypes.All Salmonella isolates were sensitive to meropenem, imipenem, spectinomycine and apramycine, and the resistance rates to chloramphenicol, kanamycine and gentamicine were less than 10%, and the resistance rates to amoxicillin, streptomycine, flumequine, oxolinique, sulfamethizol, tetracycline and nitrofurantoine ranged between 50% and 90%, while the resistance rates to penicilline, oxacilline, fusidique, rifampicine and metronidazole reached to 100%.The results indicated that the serotype distribution of pathogenic Salmonella from chickens exhibited regional characteristics, and S.typhimurium and S.pullorum were the predominant serotypes in Guangxi Zhuang Autonomous region, and antibiotic resistance of Salmonella isolates was very serious which should be highly concerned. 相似文献