Summary The objective of this study was to develop a cryopreservation method in Probarbus jullieni sperm, an endangered riverine fish species in Southeast Asia, including the optimization of an extender solution (14 extender formulations were tested) and selecting a cryoprotectant (five types of agents and methanol were used at concentrations (v/v) of 5, 7.5, 9, 10, 12, 15 and 20%). The semen to diluent ratios tested were as follow: 1 : 1, 1 : 2, 1 : 3, 1 : 4, 1 : 5, 1 : 7, 1 : 9, 1 : 14, 1 : 19, 1 : 24 and 1 : 49. Vapour exposure duration was set at 5, 10, 15 and 20 min while the distance between sample and liquid nitrogen (LN2) during the vapour exposure was designed at 3, 3.5, 4, 5 and 6 cm. Further, the time frame for thawing was set at 6, 7, 8, 10, 20 and 30 s. The optimum protocol was by using CF‐HBSS (pH 7.5, osmolality 285 ± 10 mOsmol kg−1) in combination with methanol at 9% (v/v); sperm to diluents ratio between 1 : 3 to 1 : 5; vapour exposure for 5 min or 10 min, with samples placed at 3.5 cm or 4 cm above LN2 and thawing at 40°C for 7 s. The mean of pre‐frozen and post‐thaw sperm motility was 80.1 ± 13.6% (n = 43) and 49.6 ± 16.4% (n = 43) respectively. The reproductive characteristics of P. jullieni during its spawning season were addressed in present work. Cryopreserved sperm was found to have lower fertilization ability (4.2 ± 2.5%, n = 1050) and hatching rate (1.6 ± 1.2%, n = 1050) compared with fresh sperm (fertilization 77.7 ± 6.2%, n = 1050; hatching 64.7 ± 7.7%, n = 1050). The resulted problems and constraints encountered in the process of sperm cryopreservation of the species studied were also reported in this paper.
The anatomy of the auricular conchae of ruminants has been studied by intravascular injection of radiopaque latex, by dissection and by histological sectioning. Drawings were made of the vascular network. The arrangement of nerves and blood vessels in association with the ridges on the rostral (concave) surface was observed. The spaces between the ridges are relatively free of larger blood vessels, nerves, hair and sebaceous glands. This distribution is discussed in relation to the insertion of ear tags.
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