IGEVET - Instituto de Genética Veterinaria "Ing. Fernando N. Dulout" (UNLP-CONICET LA PLATA), Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, calle 60 y 118 s/n, 1900, La Plata, Buenos Aires, Argentina.
Cátedra de Fisiología (FCV-UNLP) Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, calle 60 y 118 s/n, 1900, La Plata, Buenos Aires, Argentina.
Biol Trace Elem Res. 2021 Jan;199(1):120-125. doi: 10.1007/s12011-020-02145-4. Epub 2020 Apr 19.
Mannheimia haemolytica is the main bacterial pathogen isolated in bovine respiratory disease (BRD), a common disease affecting calves before weaning. Previous research has shown that experimental infection with bovine herpesvirus 1, a respiratory virus, decreases plasma zinc (Zn) levels. However, changes in plasma Zn concentrations in calves experimentally infected with M. haemolytica have not been studied thus far. The objective of this study was to evaluate the effect of experimental infection with M. haemolytica on plasma Zn concentration in calves. Total leukocyte count and bovine respiratory disease (BRD) clinical score were also evaluated. We conducted a 6-day trial in 14 male Holstein calves randomly assigned to one of two groups, experimental (EG, n = 8) and control (CG, n = 6). Animals in EG were intrabronchially inoculated with M. haemolytica (6.5 × 10 CFU/mL) on day 0 of the trial. Plasma Zn levels were affected by time, treatment, and time by treatment interaction, being lower in EG compared with CG on days 1, 2, and 3. Differences in total leukocyte count were significant on day 1, observing a tendency on day 3. BRD clinical score differed between groups, being higher in EG throughout the trial. We conclude that experimental M. haemolytica infection reduced plasma Zn concentration in clinically ill calves, suggesting that the clinical condition of animals (healthy/ill) should be considered to better interpret plasma Zn values.
溶血曼海姆菌是牛呼吸道疾病（BRD）中主要分离的细菌病原体，BRD 是一种影响断奶前犊牛的常见疾病。先前的研究表明，实验感染呼吸病毒牛疱疹病毒 1 会降低血浆锌（Zn）水平。然而，迄今为止，尚未研究实验感染溶血曼海姆菌对犊牛血浆 Zn 浓度的变化。本研究旨在评估实验感染溶血曼海姆菌对犊牛血浆 Zn 浓度的影响。还评估了总白细胞计数和牛呼吸道疾病（BRD）临床评分。我们在 14 头雄性荷斯坦犊牛中进行了为期 6 天的试验，这些犊牛随机分为两组，实验组（EG，n = 8）和对照组（CG，n = 6）。EG 中的动物在试验的第 0 天通过支气管内接种溶血曼海姆菌（6.5×10 CFU/mL）。血浆 Zn 水平受时间、处理和时间与处理相互作用的影响，在第 1、2 和 3 天 EG 低于 CG。第 1 天总白细胞计数差异显著，第 3 天有趋势。BRD 临床评分在组间存在差异，EG 在整个试验中更高。我们得出结论，实验性溶血曼海姆菌感染降低了临床患病犊牛的血浆 Zn 浓度，这表明动物的临床状况（健康/患病）应被考虑以更好地解释血浆 Zn 值。
