Effect of Dietary Supplementation with Cod Liver Oil on Cold Shock and Freezability of Boar Semen

Abstract

Contents The effect of dietary supplementation with cod liver oil (CLO), which is rich in n‐3 polyunsaturated fatty acids (PUFAs), on resistance to cold shock and on freezability of boar semen was investigated. Ejaculates from 29 fertile Norwegian Landrace boars, randomly divided into control (n = 15) and CLO‐group (n = 14), were frozen before and after a 12 week period of daily oil supplementation. Before each freezing, semen samples were taken to determine the fatty acid composition of the spermatozoa. Docosahexaenoic acid (22 : 6n‐3; DHA) was the major fatty acid in total lipids. The n‐3 fatty acid DHA increased in the CLO‐group from 25.5 to 32.1% at the expense of the n‐6 docosapentaenoic acid (22 : 5n‐6), which decreased from 11.3 to 4.2% (p < 0.0001). The concentration of these fatty acids were unchanged in the control group. There was also a significant decrease of other PUFAs in the CLO‐group (p < 0.05). Eicosapentaenoic acid (20 : 5n‐3) was not found in any sample. At four different steps of the preservation process (30, 15, 5°C and after freezing/thawing) both motility and acrosome integrity were assessed. No significant differences were found either within or between the groups at any of the steps. In conclusion, CLO‐supplementation alters the lipid composition of the membranes of boar spermatozoa, however, this does not seem to have any beneficial effect on cold shock and freezability of boar semen.

Effects of dietary n-3 fatty acids on characteristics and lipid composition of ovine sperm

“…Furthermore, we recently reported that dietary fish oil supplementation improved the total number and sperm concentration, motility and progressive motility of goat sperm during the non-breeding season (Dolatpanah et al, 2008). In contrast, other studies (Paulenz et al, 1999;Blesbois et al, 2004) reported no effect of dietary fish oil supplementation on sperm motility in various animal species. The apparently discordant results reported on the effect of feeding C22:6n-3 on sperm motility might be related to the different experimental techniques used.…”

Efeito da fonte de óleo e dos níveis de suplementação de vitamina E na ração sobre o congelamento de sêmen de suínos

“…Os valores médios das características observadas aproximam-se dos padrões de normalidade considerados para a espécie (CBRA, 1998 A motilidade espermática total no pós-descongelamento obtida neste estudo foi mais baixa em relação a outros estudos com sêmen suíno congelado: 38,8% (Paulenz et al, 1999), 40,9% (Murgas et al, 2001), 44,6% (Cerolini et al, 2001), 36% (Bianchi et al, 2005b, utilizando o protocolo de Westendorf et al (1975 e 51,4% (Ohata et al, 2005). Isto pode ser explicado pelo tipo de protocolo de resfriamento e congelamento utilizado, pois os autores adotaram protocolos diferenciados para congelamento do sêmen que foi associado ao período de incubação do sêmen antes do resfriamento.…”

“…A alteração da composição de lipídios da membrana espermática afeta o congelamento dos espermatozoides (Steponkus et al, 1983) e a possibilidade de aumentar a congelabilidade de espermatozoides suínos por meio da alteração da constituição da membrana espermática, como exemplo o aumento do teor de DHA na membrana plasmática por meio de sua adição à dieta, é considerada (Penny et al, 2000). O aumento deliberado do grau de insaturações e, portanto da fluidez da membrana, poderia aumentar a resistência dos espermatozoides suínos aos danos causados pelo processo de resfriamento/ descongelamento (Paulenz et al, 1999).…”