Faculty of Agriculture, Department of Animal Science, Ege University, Izmir 35100, Turkey.
Poult Sci. 2010 May;89(5):974-85. doi: 10.3382/ps.2009-00293.
The development of ascites was investigated in broilers at low versus high altitudes, cold versus normal ambient temperatures (AT), and 3 feeding regimens. One-day-old chicks obtained at sea level were reared at high altitude (highA; 1,720 m; n = 576) with 2 AT treatments, low AT from 3 wk onward at highA (highA/cold) and normal AT from 3 wk onward at highA (highA/norm), or at sea level (normal AT from 3 wk onward at low altitude, lowA/norm; n = 540). Under highA/cold, AT ranged between 16 to 17 degrees C in the fourth week, 17 to 19 degrees C in the fifth week, and 19 to 21 degrees C thereafter. Under highA/norm and lowA/norm, AT was 24 degrees C in the fourth week and ranged between 22 to 24 degrees C thereafter. Broilers in each condition were divided into 3 groups: feed restriction (FR) from 7 to 14 d, FR from 7 to 21 d, and ad libitum (AL). Ascites mortality and related parameters were recorded. Low mortality (0.4%) occurred under lowA/norm conditions. Under highA/norm, mortality was lower in females (8.6%) than in males (13.8%) and was not affected by the feeding regimen. The highA/cold treatment resulted in higher mortality but only in males; it was 44.2% among highA/cold AL-fed males and only about 26% under the FR regimens, suggesting that FR helped some males to better acclimatize to the highA/cold environment and avoid ascites. However, mortality was only 13.3% in AL-fed males at highA/norm and FR did not further reduce the incidence of ascites under these conditions. Thus, avoiding low AT in the poultry house by slight heating was more effective than FR in reducing ascites mortality at highA. Compared with FR from 7 to 14 d, FR from 7 to 21 d did not further reduce mortality and reduced growth. At 47 d, the majority of surviving broilers at highA had high levels of hematocrit and right ventricle:total ventricle weight ratio (>0.29), but they were healthy and reached approximately the same BW as their counterparts at low altitude. This finding may suggest that in broilers reared at highA from day of hatch, the elevation in hematocrit and in right ventricle:total ventricle weight ratio happens gradually and therefore is not necessarily indicative of ascites development.
在低海拔与高海拔、常温与低温、三种饲养方案下，研究了肉鸡腹水的发生情况。在海平面获得的 1 日龄雏鸡在高海拔（高 A；1720 米）饲养，有两种环境温度处理，高 A 区从第 3 周开始采用低温（高 A/冷），高 A 区从第 3 周开始采用常温（高 A/常），或在低海拔（低 A/常，从第 3 周开始采用常温）。在高 A/冷条件下，第四周的环境温度在 16 到 17 度之间，第五周在 17 到 19 度之间，此后在 19 到 21 度之间。在高 A/常和低 A/常条件下，第四周环境温度为 24 度，此后在 22 到 24 度之间。在每个条件下，肉鸡分为三组：7 到 14 天的限饲（FR），7 到 21 天的 FR，自由采食（AL）。记录腹水死亡率和相关参数。低死亡率（0.4%）发生在低 A/常条件下。在高 A/常条件下，雌性（8.6%）的死亡率低于雄性（13.8%），不受饲养方案的影响。高 A/冷处理导致更高的死亡率，但仅在雄性中；在高 A/冷 AL 喂养的雄性中为 44.2%，而在 FR 方案中仅约为 26%，表明 FR 有助于一些雄性更好地适应高 A/冷环境并避免腹水。然而，在高 A/常条件下，AL 喂养的雄性死亡率仅为 13.3%，FR 并不能进一步降低腹水的发生率。因此，通过轻微加热避免家禽舍中的低温比 FR 在高海拔地区更有效地降低腹水死亡率。与 7 到 14 天的 FR 相比，7 到 21 天的 FR 并没有进一步降低死亡率和生长速度。在 47 天时，大多数在高 A 条件下幸存的肉鸡的红细胞压积和右心室/总心室重量比都很高（>0.29），但它们是健康的，达到了与低海拔地区相当的体重。这一发现可能表明，在从孵化日起就在高海拔地区饲养的肉鸡中，红细胞压积和右心室/总心室重量比的升高是逐渐发生的，因此不一定表明腹水的发生。
