Maturational changes in the survivability and fertility of fowl sperm during their passage through the male reproductive tract

The objective of this study was to examine whether domestic fowl (Gallus domesticus) sperm undergo maturation in their capacity for survival and fertilization in the male reproductive tract. Sperm collected from the testis, epididymis and the proximal, middle and distal vas deferens were simultaneously stored in vitro in minimum essential medium (MEM) at 39 degrees C for 0, 3 and 6 h, and at 4 degrees C for 24 and 48 h. Sperm membrane integrity was measured using the dual fluorescent stain SYBR-14/propidium iodide (PI). Aliquots of sperm from the various sites were subjected to artificial insemination (AI) into the uteri of hens to assess the duration of sperm survival in the oviduct and to determine the fertility status of the sperm. Testicular sperm exhibited a very low capacity to survive under in vitro liquid storage conditions, irrespective of the storage temperature used, and in the oviduct, and they had a low ability to fertilize the ovum. On the contrary, sperm from the distal vas deferens had a higher survival rate during in vitro storage periods, a longer life span in the oviduct, and high fertility. Survival and fertilizing capacity of the sperm recovered from the testes increased gradually (P < 0.05) from the testes to the distal vas deferens. In conclusion, we suggest that fowl sperm may undergo functional maturation through a process of gradual changes in their survival and fertilization capacities during their passage through the successive parts of the male reproductive tract. (C) 2011 Elsevier B.V. All rights reserved.

本研究的目的是检验家禽（鸡）精子在雄性生殖道中其存活和受精能力是否经历成熟过程。从睾丸、附睾以及近端、中端和远端输精管收集的精子同时在体外基本必需培养基（MEM）中于39℃保存0、3和6小时，以及在4℃保存24和48小时。使用双重荧光染色剂SYBR - 14/碘化丙啶（PI）测量精子膜完整性。来自不同部位的精子等分试样进行人工授精（AI）到母鸡的子宫中，以评估精子在输卵管中的存活时间并确定精子的受精状态。无论使用何种储存温度，睾丸精子在体外液体储存条件下以及在输卵管中都表现出极低的存活能力，并且它们使卵子受精的能力也很低。相反，来自远端输精管的精子在体外储存期间具有较高的存活率，在输卵管中具有较长的寿命，并且受精率高。从睾丸回收的精子的存活和受精能力从睾丸到远端输精管逐渐增加（P < 0.05）。总之，我们认为家禽精子在通过雄性生殖道的连续部分时，可能通过其存活和受精能力逐渐变化的过程经历功能成熟。（C）2011爱思唯尔B.V.保留所有权利。