29 September 2000

Quality sperm comes from additive to diet

Improving performance and competitiveness of the

UK pig industry was the theme of last weeks JSR

Healthbred conference. Emma Penny reports

SUPPLEMENTING boars with fatty acids they cannot produce and which their diet is deficient in will increase fertility.

Launched last week by JSR Clover (Livestock, Sept 22), the feed supplement Prosperm results in more consistent sperm production and sperm which is much more motile and of better quality.

Reproductive biologist Andre Maldjain told the conference at Sutton Bonnington, Notts, that fatty acids are a major building block of all fats. They are required for maintenance of health and well-being as their role in cell control and function is critical.

In most tissues, long chain polyunsaturated acids account for about 6% of the total fatty acids present, but in spermatozoa, they an account for 60-65% of total fatty acids – the major one being DHA.

While levels of DHA in bulls and rams can be up to 60% of fatty acid content, boars under modern breeding conditions may only have 30% DHA. Dr Maldjain and research colleagues at JSR believe this may be due to imposing dietary and environmental constraints, which could compromise natural fatty acid supply. Low DHA levels and an increase in another fatty acid – DPA – correlate with reduced fertility, he added.

The feed supplement – fed at about 250g/day as pellets top-dressed onto rations – aims to boost DHA levels and so fertility. Trials on 35 boars at JSR Healthbred were carried out to prove the theory, with boars fed the supplement for 16 weeks, covering the six week spermatogenesis period.

Between weeks four and eight, a significantly higher proportion of spermatozoa were found to be alive when treated boars were tested – 88% compared with 73% from untreated boars, while the figures at 16 weeks were 89% and 70%, respectively.

"We found that figures reached a plateau and were much more consistent for treated boars at 85-90%, while the proportion of spermatozoa alive from untreated boars varied throughout the trial period."

The number of spermatozoa per ejaculate was also higher from treated boars at 83-84bn cells compared with 74bn from untreated boars. Spermatozoa were also more mobile, scoring 4.5 compared with 3.9 from untreated boars, suggesting that cell membranes in supplemented boars were more flexible.

During trials, 478 gilts were served using 100% AI under commercial conditions, comparing the control – the boars usual diet – and boars receiving the Prosperm supplement. While 83% of control gilts conceived, 90% of gilts served with semen from supplemented boars conceived.

At farrowing, control pigs produced 10.5 piglets, with 10.2 born alive, compared with treatment gilts which produced 11 piglets born and 10.6 born alive. Live birth figures per 100 services were 845 for control pigs and 650 for treatment gilts.

PROSPERM

&#8226 Feed supplement.

&#8226 Improves semen quality.

&#8226 Better boar fertility.