58 EFFECT OF MELATONIN IMPLANT ON BLANCA de RASQUERA BUCKS DURING SPRING ON SPERM MORPHOMETRY BEFORE AND AFTER CRYOPRESERVATION

Abstract

In order to improve sperm cryopreservation throughout the year and accelerate the process of preservation of this Catalonian goat breed in extinction danger, we proposed to assess the effect of melatonin implant application in Blanca de Rasquera males during spring on sperm head morphometry of fresh and thawed sperm. Therefore 8 bucks of 30 months old approximately were divided into 2 groups. In one of the groups, 2 melatonin implants (Melovine®, CEVA) were inserted into bucks 60 days before starting the collection of semen, and the other group was kept untreated. Briefly, fresh ejaculates from each group of 4 bucks were collected in spring, immediately mixed in equal quantities, and centrifuged twice (600 g for 10 min). Then the pellet was resuspended in a Tris-based medium containing 15% (v/v) of powdered egg yolk supplemented with 5% glycerol. Afterward, sperm samples were refrigerated at 5°C for 4 h before being frozen in LN vapour. Buck sperm head morphometry was analysed by computer-assisted sperm analysis (ISAS®) on fresh and thawed sperm previously stained with Diff Quick®. Data were analysed by GLM multivariate procedure (IBM SPSS, 2011; mean ± s.e., n = 6), showing significant differences among treatments in all the morphometric parameters except head perimeter and rugosity (Table 1). Our results suggest that melatonin application in bucks increases the ellipticity and elongation of fresh and thawed sperm, meanwhile the cryopreservation process reduces both parameters. Likewise melatonin implants increase significantly the head length only on thawed sperms as cryopreservation process increases the head width, area in sperms from implanted males and regularity only in sperms from nonimplanted bucks. These head changes on fresh and thawed sperm morphometry should be deeply investigated in order to know how they could affect sperm cryosurvival and fertility.

Table 1.  Effect of melatonin implant on Blanca de Rasquera bucks during spring on morphometry of fresh and thawed sperm

This research was supported by INIA (RZ2009–00008–00–00), Generalitat de Catalunya (2009SGR0621 and CUR-DIUE), and FSE and Fundación Carolina.