Branton S L, Lott B D, Austin F W, Pharr G T
USDA, Agricultural Research Service, South Central Poultry Research Laboratory, Mississippi State, Mississippi 39762, USA.
Avian Dis. 1997 Oct-Dec;41(4):930-4.
In each of three trials, 150 day-old broiler chicks were eyedrop inoculated with 0.04 ml of high-passage F strain Mycoplasma gallisepticum (MG) and housed in biological isolation units at 10 chicks per unit. At 4 wk of age, 50 chickens were designated as controls and remained on tap water (pH 7.30), 50 chickens were provided tap water containing 0.63% ammonium chloride (NH4Cl, pH 6.91), and 50 chickens were provided tap water containing 1.26% sodium bicarbonate (NaHCO3, pH 8.17). Fluids were supplied for ad libitum consumption. At 5 wk of age, all chickens were swabbed from the choanal cleft for MG isolation and bled from the left cutanea ulnea vein for pH determination. As a percent of total swabs obtained, significantly fewer chickens that consumed water containing NH4Cl (38.3%) were positive for MG by culture compared with either the NaHCO3 group (61.3%) or the control group (67.6%). Nonmycoplasmal swab contamination was significantly higher for chickens that consumed water containing NH4Cl (59.7%) compared with either controls (31.8%) or NaHCO3-treated chickens (38.7%). When contaminated cultures were discarded, MG isolations from the tap water group were not significantly different from MG isolations from either the NH4Cl or NaHCO3 group. However, MG isolations from the NH4Cl group (95%) were significantly less compared with the NaHCO3 group (100%). Mortality was significantly higher in chickens that consumed water containing NaHCO3 (8.7%) compared with either controls (1.3%) or the NH4Cl-treated chickens (0.7%). Blood pH values were lower for the NH4Cl group (7.927), higher for the NaHCO3 group (8.093), and intermediate for controls (8.035). Results of this study suggest that water containing NH4Cl hinders the bacteriological recovery of MG from the choanal cleft.
在三项试验中的每一项中，150只1日龄的肉鸡雏鸡通过滴眼接种0.04毫升高传代F株鸡毒支原体（MG），并以每单元10只鸡的数量饲养在生物隔离单元中。在4周龄时，50只鸡被指定为对照组，饮用自来水（pH 7.30），50只鸡饮用含有0.63%氯化铵（NH4Cl，pH 6.91）的自来水，50只鸡饮用含有1.26%碳酸氢钠（NaHCO3，pH 8.17）的自来水。随意供应饮水。在5周龄时，所有鸡都从后鼻孔裂隙处取样进行MG分离，并从左尺侧皮静脉采血进行pH测定。作为所获总样本的百分比，与饮用NaHCO3组（61.3%）或对照组（67.6%）相比，饮用含NH4Cl水的鸡通过培养检测出MG阳性的数量显著更少。饮用含NH4Cl水的鸡（59.7%）的非支原体样本污染显著高于对照组（31.8%）或经NaHCO3处理的鸡（38.7%）。当丢弃污染培养物时，自来水组的MG分离率与NH4Cl组或NaHCO3组的MG分离率无显著差异。然而，NH4Cl组的MG分离率（95%）显著低于NaHCO3组（100%）。饮用含NaHCO3水的鸡的死亡率（8.7%）显著高于对照组（1.3%）或经NH4Cl处理的鸡（0.7%）。NH4Cl组的血液pH值较低（7.927），NaHCO3组较高（8.093），对照组居中（8.035）。本研究结果表明，含NH4Cl的水会阻碍从后鼻孔裂隙处进行MG的细菌学回收。
