YAIKUULA (WIND-DRIVEN EVAPORATIVE COOLING) SAVES MOST GUINEA FOWL EGGS FOR HATCHING IN THE SUDANO-SAHELIAN BELT

Guinea fowl meat and eggs are highly prized by consumers in the Sudan-Sahelian belt countries such as Burkina Faso and Niger. However, compared to chicken, guinea fowl stocks in these countries are low. One of the reasons for the low stock holdings is that guinea fowl in captivity are poor at being broody hens. They do not sit on their eggs for the hatching of their keets. This problem has been addressed using synchronized surrogate chicken hens for brooding. Many chicken hens are provided with dummy eggs until they begin to brood, at which time the dummy eggs are switched to fertile guinea fowl eggs. The challenge with this solution is storing the guinea fowl eggs at room or ambient temperatures until the surrogate brooders are ready. The high room temperatures during storage initiates preembryo development that results in hatching unhealthy keets. Refrigerated storage is not an option, as most smallholder farmers in rural settings do not have access to electricity. The purpose of this study was to address the storage problem by introducing wind-driven evaporative cooling (YaiKuula); “Yai” is a Swahili word for “egg.” YaiKuula lowers the storage temperature ~15oC below ambient temperature during the day. Viable guinea fowl eggs were stored using YaiKuula for 0-3, 4-7, and 8-14 days. Ambient temperature and refrigerated (8oC) storage were done in parallel as negative and positive controls, respectively. Twenty-four surrogate brooders with six eggs each were used to hatch the stored eggs. Early and late embryo mortality, in addition to healthy hatching were monitored. The Student’s ttest was used to compare results. The highest rate (p<0.05) of early embryonic mortality (65%) was obtained with refrigerated storage for 8-14 days versus 37 and 12%, respectively, for ambient and YaiKuula storage for the same length of time. The hatching rates of eggs from 0-3 days of storage showed no significant difference between the three storage methods. However, YaiKuula storage yielded significantly (p<0.05) higher hatching rates of 80% versus 37 and 22% from ambient and refrigeration storage at 8-14 days, respectively, and 84% versus 65 and 61% for ambient and refrigeration storage at 4-7 days, respectively. YaiKuula has the potential to increase the number of guinea fowl among smallholder poultry farmers for increased incomes/resilience and better nutrition.

在布基纳法索、尼日尔等苏丹-萨赫勒地带（Sudan-Sahelian belt）国家，珍珠鸡（guinea fowl）的肉与蛋深受消费者青睐，但相较家鸡（chicken），上述国家的珍珠鸡存栏量始终偏低。存栏量偏低的原因之一在于，圈养状态下的珍珠鸡就巢性极差，不会伏卧于蛋上孵化雏珠鸡（keets）。针对该问题，此前采用同步代孵家鸡（surrogate chicken hens）的方案进行解决：先向多只家鸡提供假蛋，直至其进入就巢状态，随后将假蛋替换为受精的珍珠鸡蛋。但该方案存在一项挑战：需在代孵家鸡准备就绪前，将珍珠鸡蛋储存于室温或环境温度下；而储存期间的高温会启动胚胎前期发育，最终导致孵化出的雏珠鸡不健康。由于多数农村小农户（smallholder farmers）无法获取电力，冷藏储存并不具备可行性。本研究旨在通过引入风驱蒸发冷却（wind-driven evaporative cooling，命名为YaiKuula）解决上述储存难题；“Yai”在斯瓦希里语中意为“鸡蛋”。YaiKuula可在日间将储存温度较环境温度降低约15℃。研究人员将可育珍珠鸡蛋分别采用YaiKuula储存0~3天、4~7天及8~14天；同时设置环境温度储存与8℃冷藏储存作为平行对照，分别作为阴性对照与阳性对照。选用24只代孵母鸡，每只孵化6枚储存后的鸡蛋，同时监测早期胚胎死亡率、晚期胚胎死亡率以及健康雏珠鸡的孵化率。实验采用Student’s t检验（Student's t-test）对结果进行比较分析。结果显示，冷藏储存8~14天的早期胚胎死亡率最高，达65%（p<0.05）；同期环境温度储存与YaiKuula储存的早期胚胎死亡率分别为37%与12%。储存0~3天的鸡蛋，三种储存方式的孵化率无显著差异。但在8~14天储存组中，YaiKuula储存的孵化率达80%，显著（p<0.05）高于环境储存的37%与冷藏储存的22%；在4~7天储存组中，YaiKuula储存的孵化率为84%，同样显著高于环境储存的65%与冷藏储存的61%。YaiKuula有望提升小型家禽养殖户的珍珠鸡存栏规模，进而增加养殖户收入、增强其抗风险能力并改善营养状况。