Viabilidade do sêmen caprino conservado em três diferentes diluidores: efeito da concentração inicial de frutose no plasma seminal

Abstract

One of the main objectives of the artificial insemination program in goats is to produce the highest number of descendants of genetically superior animals with the purpose to improve the animal production. Thus, it is necessary to dominate correct techniques of dilution and semen storage in this specie. In this work three different extenders had been tested: citrate-egg yolk (CE), TRIS-egg yolk (TE) and industrialized coconut water (ICW) and two groups of animals: with high initial level of fructose (group I) and with low initial level of fructose (group II) in the seminal plasma. The semen was stored until 48h at 5oC and evaluated in times 0 (fresh), 2, 24 and 48h, where a sample of the conserved semen was submitted to the term-resistance test (TTR) that consists of incubate the sample at 38oC for 2h. During the incubation it had been verified the parameters of Motility (MOT) and vigor (VIG), in times 5, 60 and 120 minutes and to the end was calculated the tax of degradation of the motility (TDM) and semen slides had been carried through for verification of the possible morphologic alterations. It had a significant fall in the parameters analyzed in elapsing of the time of storage, independent of the used extender (P<0,05). However, extender ICW presented inferior resulted than the others. The effect of the group was observed only in the ICW,showing that this extender did not supply the energy necessities of the spermatozoa whose initial concentration of fructose in the plasma was low. CE and TE worked similarly in the two groups. Significant difference in the activity of phospholipase A2 between the groups was found (P<05), in way that a bigger activity was observed in group II. In conclusion, independent of the used extender, the seminal parameters tend to fall as draw out the conservation time. Moreover, the initial concentration of fructose did not intervene with the sperm quality when extenders CE and TE had been used, however, when the levels of this component in the seminal plasma had been superior to 740mg/dL, occurred an increase in lifetime of the spermatozoa conserved at 5oC, when ICW was used. It suggests that sperm low action also can be due to a higher activity of PLA2, however more studies are necessary, with a large number of animals to elucidate this hypothesis