A total of 960 male Cobb 500 broilers were used in a growth performance study to explore the effect of coccidial vaccination and/or coccidial challenge on blood biochemistry and veterinary postmortem metrics. Day-old chicks were randomly divided into one of the 4 experimental treatments. Treatments were arranged in a 2 × 2 factorial arrangement, with the factors being without or with vaccination (administered on day 1) or coccidial challenge (oral gavage on day 7). Growth performance was monitored on a weekly basis. Blood sample collection, as well as full veterinary necropsies, were carried out on days 6, 8, 13, 20, 27, and 34. Birds that did not receive the vaccination but were challenged with coccidiosis had higher feed conversion ratio, lower body weights, and higher mortality than the other experimental groups, and this effect was particularly evident from day 13 to day 20. Birds challenged with coccidiosis had lower plasma sodium and total carotenoid concentrations and higher potassium and globulin concentrations than nonchallenged birds. Significant interactions between age and experimental treatment for these blood parameters were observed, particularly on day 13. The necropsy results confirmed the effectiveness of the challenge and vaccination treatments, wherein birds that were challenged had higher coccidiosis scores on day 13 and day 27 than birds that were not challenged. These results demonstrate the potential for plasma sodium, potassium, total protein, total carbon dioxide, globulin, and carotenoid analysis for early diagnosis of coccidiosis in growing broiler chickens. Further work is necessary to establish whether the changes in blood biochemistry observed in the present study are transferable to alternative flocks of chicken and whether early diagnosis and intervention may mitigate performance losses associated with this disease.

中文翻译：

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球菌攻击和疫苗接种对肉鸡生产性能，兽医死后评分和血液生化的影响。

总共960头Cobb 500雄性肉鸡用于生长性能研究，以探索球虫疫苗接种和/或球虫攻击对血液生化和兽医死后指标的影响。将日龄小鸡随机分为4种实验处理之一。治疗以2×2析因排列，因子不接种或接种疫苗（在第1天施用）或球虫攻击（在第7天进行管饲）。每周监测生长性能。在第6、8、13、20、27和34天进行了血液样本采集以及完整的兽医尸检。未接种疫苗但受到球虫病攻击的禽类具有较高的饲料转化率，较低的体重，并且死亡率高于其他实验组，从第13天到第20天，这种效果尤为明显。与无挑战性的鸟类相比，受到球虫病攻击的鸟类的血浆钠和总类胡萝卜素浓度较低，钾和球蛋白的浓度较高。观察到年龄和这些血液参数的实验治疗之间的显着相互作用，尤其是在第13天。尸检结果证实了挑战和疫苗接种治疗的有效性，其中被挑战的鸟类在第13天和第27天的球虫病评分高于那些没有受到挑战。这些结果证明了血浆钠，钾，总蛋白，总二氧化碳，球蛋白和类胡萝卜素分析潜力可用于早期诊断成年肉鸡的球虫病。