H. Paulenz et al., Effect of dietary supplementation with cod liver oil on cold shock and freezability of boar semen, REPROD DOM, 34(5), 1999, pp. 431-435
The effect of dietary supplementation with cod liver oil (CLO), which is ri
ch in n-3 polyunsaturated fatty acids (PUFAs), on resistance to cold shock
and on freezability of boar semen was investigated. Ejaculates from 29 fert
ile Norwegian Landrace boars, randomly divided into control (n = 15) and CL
O-group (n = 14), were frozen before and after a 12 week period of daily oi
l supplementation. Before each freezing, semen samples were taken to determ
ine 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 contr
ol group. There was also a significant decrease of other PUFAs in the CLO-g
roup (p < 0.05). Eicosapentaenoic acid (20 : 5n-3) was not found in any sam
ple. At four different steps of the preservation process (30, 15, 5 degrees
C and after freezing/thawing) both motility and acrosome integrity were as
sessed. No significant differences were found either within or between the
groups at any of the steps. In conclusion, CLO-supplementation alters the l
ipid composition of the membranes of boar spermatozoa, however, this does n
ot seem to have any beneficial effect on cold shock and freezability of boa
r semen.