蛋用型祖代鸡群禽白血病病毒感染状态的持续观察

为了检测从国外直接进口的蛋用型祖代鸡群是否存在外源性禽白血病病毒(ALV)的感染,将240只1日龄鸡饲养在严格的SPF环境中。在不同日龄采集泄殖腔棉拭子检测ALV群特异性p27抗原、采集血浆分离外源性ALV和采集血清检测ALV-AB及J特异性抗体。结果表明:在近3个月的6次采样检测中,6个不同的配套系间泄殖腔棉拭子检出率显著不同。其中1个配套系6次完全阴性,其余5个则在不同时期呈间隙性阳性。各品系之间ALV p27抗原检出率与快慢羽性状没有相关性。慢羽的配套系C,36只鸡中在45日龄检出了1例ALV-AB抗体一过性阳性,在60日龄检出了2例ALV-J抗体一过性阳性。分别在5、21日龄采血浆在DF1细胞分离病毒,所有的6个配套系的204只鸡外源性ALV的病毒分离均为阴性。     

Leptin receptor expression and its change in association with the normalization of EGF profile after seminal plasma treatment in repeat breeder dairy cows

Factors associated with high milk production levels have been linked to alterations in the endometrial epidermal growth factor (EGF) profile, a cause of reduced fertility in dairy cows. Therefore, we examined the leptin system that connects nutritional status and reproduction in dairy cattle related to reduced fertility in repeat breeder cows. Plasma leptin concentrations were measured in 18 heifers, 20 high-yielding control cows, and 26 repeat breeder cows, showing an altered EGF profile. Then, all repeat breeder cows were infused with seminal plasma (SP) into the vagina at the next estrus to normalize the EGF profile, while heifers and control cows were infused with vehicle alone. All animals were examined for EGF profiles. Eighteen repeat breeder cows, nine heifers, and nine control cows were also determined for leptin receptor (Ob-R) expression levels in the estrous cycle before and after the infusion. SP normalized the EGF profile in 53.8% of the repeat breeder cows. Leptin concentrations were similar in all groups, regardless of the treatment results for the EGF profile. In contrast, Ob-R levels in repeat breeder and control cows were similar and higher than those in heifers before SP treatment. Ob-R in repeat breeders showing a normal EGF profile after treatment decreased to an intermediate level between heifers and control cows and may provide a clue to take measures against repeat breeding in dairy cows.