The collection of oviductal fluid from sheep

Oviduct provides natural environment for gamete transport, fertilization an d early embryonic development. The information about composition of milieu in the oviduct at defined stage of estrus cycle is valuable for the improve ment of media employed in mammalian embryo production in vitro and for the investigation of sperm-egg interaction at fertilization. The intention of t hese studies was to collect oviductal secretion for biological assays and f or chemical analyses using permanent indwelling oviductal cannulae in 14 me rino ewes (28 oviducts). In 4 females (8 oviducts) with previously synchron ized estrus cycle the harvest of secretion was low (maximal average 0.3 ml/ day) and the flow stopped before day 7 after surgical intervention, mostly due to the oclussion by fibrinous plugs. The effect of unilateral ligation localized close to the uterotubal junction was compared in 6 ewes (6 ligate d and 6 unligated oviducts). The ligation of the oviducts promoted the func tion of the canulae for several subsequent estrous cycles, while in unligat ed counterparts the cannulae became usually occluded with fibrin mostly bef ore third cycle. In remaining 4 females (8 oviducts) in random stage of est rous cycles bilateral ligation was performed. The results show that this tr eatment was most suitable for collection of oviductal fluid. Despite fluctu ation, in 8 from totally ligated 14 oviducts the undisturbed function of ca nnulae was recorded for more than 2 estrous cycles and in two instances for 150 days. The harvested volumes of secretion were in close relation to the estrous cycle with typical highest amount around the heat (1.2 mi per day) and lowest at the luteal phase (0.3 ml/day). The causes of flow cesation w ere mostly the formation of fibrinous plugs at the junction with oviduct or evulsion of cannulae by the subject. Nevertheless, the experiments indicat e that cannulae may represent effective method for collection of oviductal secretion for biochemical analysis or direct physiological experiments.