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Newsletter December 2017

Zinc and the intestinal health of broiler chickens

In a 4-year research project ILVO and UGENT attempt to unravel the impact and the mode of action of zinc at the intestinal level in broilers. A first trial reveals a positive effect of supplementation of zinc-amino acid complexes on the intestinal morphology and oxidative stress.

zinc and intestinal healthZinc is an essential trace element, which has an important role in various biological processes in broilers, such as bone formation, feathering, protein & DNA synthesis, immunity, cell replication and wound healing. Therefore, it is crucial to provide sufficient zinc in the feed through readily available zinc supplements. Zinc can supplemented as in inorganic source, for example zincsulphate or organic source, such as zinc-amino acid complexes. Some studies show that supplementation of zinc improve intestinal health end reduce oxidative stress resulting in an improved growth of the broilers. Organic zinc sources are considered to be more readily bioavailable, but scientific data are scarce. To investigate the bioavailability and the effects on intestinal health a trial was conducted comparing supplementation with zinc sulphate and zinc-amino acid complexes (Zinpro corp., Eden Prairie) in broilers. The effects on digestibility, intestinal health, oxidative stress and performance were investigated.

The results for growth and feed conversion showed very good production results for both treatments. Zinc-amino acid complexes showed a lower feed conversion during the starter period and a strong trend for an improved feed conversion during the grower period. The digestibility trial showed an improved zinc absorption for zinc-amino acid complexes compared to zinc sulphate, which shows a better bioavailability. Supplementation with zinc-amino acid complexes showed a higher villus length and villus length to crypt depth ratio. An increase in villus length is associated with an increase in digestion and absorption of nutrients, while an increase in ratio is associated with a lower need for cell renewal. Zinc-amino acid complexes therefore were shown to improve intestinal health in broilers.

The effects on oxidative stress were also monitored by measuring malondialdehyde (endproduct of lipid peroxidation) and glutathione peroxidase activity (enzyme that neutralizes oxygen radicals). At slaughter age there was no difference in malondialdehyde levels, but there was a difference in glutathione peroxidase levels. Supplementation with zin-amino acid complexes show a lower enzyme activity to maintain the same oxidative status.

The first trial shows that supplementation with zinc-amino acid complexes has a positive impact on villus morphology and a reduction in oxidative stress. It also shows an improved production during starter period and a strong trend for an improved production during the grower period. More insights in the mode of action of zinc will allow to better support the intestinal health and needs of the broilers. 

Project: intestinal health in broilers
Term: January 2016 to December 2019