Wetenschap - 19 januari 2018

Natural antibodies make laying hens robust

tekst:
Albert Sikkema
2

Laying hens whose blood is richer in natural antibodies have better immunity to diseases. This was revealed by the PhD research Tom Berghof carried out at the Adaptation Physiology and Animal Breeding and Genetics groups. He expects that farms will be able to use this knowledge to breed hens with better natural immunity.

©Tom Berghof

Some hens are more likely to catch a disease than others. If a nasty bacterium haunts through a coop, some hens will perish while others will survive. This natural variation is partially genetically defined, as was discovered by one of Tom Berghof’s predecessors at the Adaptation Physiology group. She found that laying hens with high amounts of natural antibodies have a lower mortality. ‘That was the starting point of my research’, says Berghof.

Natural antibodies are part of the hen’s immune system. These proteins recognise pathogens which the animal has not encountered before. Berghof thinks that they recognise and inhibit all bacterial pathogens. He has proven the working of the antibodies on one type of bacterium.

Breeding lines
Berghof was given a female breeding line from the breeding company Hendrix Genetics. He measured the amounts of natural antibodies in the hens’ blood at sixteen weeks old. Following this procedure, he selected two lines of hens with high and low levels of natural antibodies. After four and six generations, he exposed these ‘high’ and ‘low’ lines to pathogenic E. coli bacteria. The high line, which had over four times as many natural antibodies, was far less often infected and perished significantly slower. ‘The antibodies suppress the bacterial infection’, the PhD candidate concluded.

Production
He also made another interesting discovery. Previous research into robust hens suggested a trade-off between production and health: hens investing more in immunity produce less. But no such thing became apparent during Berghof’s experiments. ‘The chicks with more antibodies probably invest in their immunity at a young age, before they start laying eggs, and have an advantage once they do start laying.’ He advises Hendrix Genetics to breed for natural antibodies.

‘The great thing about breeding for natural antibodies is that you use the natural potential of the hens’, says Berghof. ‘Besides, the genetic approach yields a long-term improvement, as the higher immunity is permanently coded.’

Well-being
Berghof thinks this could provide considerable societal advantages. ‘A disease will not spread as easily or quickly in a coop with laying hens that have high amounts of natural antibodies, causing fewer animals to get sick too. This would lead to lower losses, higher well-being and a lesser use of antibiotics. But there will always be animal diseases that are too strong for antibodies. Those should be fought using vaccines or management measures.’

Larger experiment
Hendrix Genetics will get to work with the results. ‘This research has made clear that natural antibodies are hereditary and that selection on this characteristic contributes to an improvement of the immunity’, says Johan van Arendonk, chief Innovation & Technology Officer at Hendrix Genetics. The breeding company has set up an even larger experiment to determine what the consequences of selection for natural antibodies will be not only on the immunity, but on other characteristics as well. ‘It is of utmost importance for us to make sure the animals are balanced’, says Van Arendonk, who was professor of Animal Breeding and Genetics in Wageningen until three years ago.

Re:acties 2

  • Gert

    Open deur?
    Vergelijkbaar om te stellen dat een motorrijder met helm beter beschermd is dan zonder.

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    • Tom Berghof

      Beste Gert,

      Bedankt voor je interesse in mijn PhD thesis. Het is niet zo simpel als jij hier stelt: ja, natuurlijke antilichamen hebben positieve associaties met gezondheid/ziekteresistentie in diverse diersoorten (inclusief mens), maar of dat resulteert in (functionele) verschillende in resistentie is (was?) nog niet zo zeker...

      Wat ik in mijn thesis laat zien is dat als we kippen fokken op natuurlijke antilichamen tegen een bepaalde eiwit (een antigen) dat dit resulteert in een verschil in ziekteresistentie tegen een E. coli-ziekteverwekker (met andere, ogenschijnlijk niet gerelateerde antigenen). Dat is bijzonder!
      Daarnaast zijn in het verleden diverse vergelijkbare selectie-experimenten uitgevoerd, waarbij kippen geselecteerd werden op andere onderdelen van het afweersysteem. Dit heeft -voor zover ik weet- nog nooit geleid tot toepassing in de veefokkerij. Waarschijnlijk omdat het te duur of te moeilijk was om het selectiecriterium te meten of omdat de selectie negatieve consequenties had op productie of ziekteresistentie tegen andere ziekteverwekkers. In dit geval lijkt dat niet zo te zijn. Hendrix Genetics is op dit moment bezig met een groter praktijkexperiment om dit te onderzoeken.

      Jouw vergelijking van een motorrijder zonder helm is waarschijnlijk dichter bij een de vergelijking van een dier zonder afweersysteem. Ik stel dat er verbetering mogelijk is in de manier waarop de helm is opgebouwd en bescherming biedt. Misschien dat dit ook een open deur lijkt, maar helm is nou eenmaal minder ingewikkeld dan de biologie van een levend dier...

      Nogmaals bedankt voor je reactie. Ik geef graag toelichting op vragen of onduidelijkheden.

      Groeten,

      Tom


      P.S. I realize I answered the question in Dutch. Don't hesitate to ask me for a translation or post other questions or comments! :-)


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