For the past few decades, broilers have been selected to accelerate their growth rate. The objective of breeders is to produce more muscle and less fat, for a better quality of meat for human consumption. However, this selection has been accompanied by several health problems for the birds, including musculoskeletal, heart and fertility problems, and has made them more sensitive to oxidative stress.
To counteract these problems, farmers apply a strict diet early on and adjust it regularly. Grape seeds, from the production of grape juice and wine, are sources of many flavonoids, compounds that have antioxidant properties. Several studies in mammals show that these compounds reduce oxidative stress and may also reduce the risk of cardiovascular disease. Researchers studied the effects of adding grape seed extract to the diet of breeding hens. The results obtained on the hens themselves, on their eggs and on their offspring have just been published in 3 articles.
A beneficial effect on eggs and chicks
The researchers added 1% grape seed extract to the feed of 324 breeding hens and studied the effects of this supplementation for 40 weeks. Adding grape seeds to the diet of breeding hens, either from birth or from the 4th week after hatching, improved the quality of their eggs by reducing the number of double yolks, increasing the strength of the shell and reducing the proportion of free radicals in the yolk that can cause oxidative stress. More unexpectedly, their results also show an increase in growth rate and viability of chicks, as well as a reduction in the risk of oxidative stress, suggesting a beneficial transgenerational effect.
Better microbiota and reduced fat production
A second experiment involved 3 groups of 12 hens: a group fed a medium level (1% of the diet) of grape seed extract from a young age, a group fed a high level of grape seed extract (2% of the diet) for two weeks during the laying period, and a control group receiving no extract at all. The results show that a diet enriched with grape seed extract reduces the fat production of the hens and improves their gut microbiota and resulting functions such as gut health and reproduction. The addition of 2% grape seed extract for two weeks is sufficient to improve the metabolism of the hens and the quality of their eggs through the modification of their microbiota.
A diet enriched with grape seed extract is beneficial not only for the hen and her eggs, but also for her offspring. With the objective of developing the principles of agroecology in animal husbandry, the use of this bio-resource, available in large quantities in the juice and wine production sectors, is particularly relevant for breeders. Moreover, this supplementation could be a short-term solution to improve animal welfare, while waiting for changes in the selection criteria of broiler lines.