Embryonic development and the formation of the digestive system play a critical role in the growth of poultry after hatching. The development of bird embryos is determined by the amount of nutrients in the egg. Chicks with weaker viability develop more slowly and die at a higher rate.
- The first experiments were conducted in the 1940s, and in the 1980s, a technology was developed whereby birds were vaccinated in the egg. This possibility gave researchers the idea that various nutritious and bioactive substances could also be introduced into the egg (in ovo feeding). Numerous experiments have confirmed that injecting various substances, such as amino acids and vitamins, into chicken eggs improves intestinal development, intestinal health, and the immune system. The vast majority of these studies were conducted on meat hybrid (broiler) genotypes. Researchers have little information available on laying hens, said Csaba Szabó, head of the Department of Animal Nutrition and Physiology at the Faculty of Agriculture, Food Science and Environmental Management.
The experts' research focused on the examination of methionine supplementation in poultry embryos.
- Methionine (Met) is an essential amino acid that has numerous functions, including protein synthesis and participation in the antioxidant system. Poultry have a higher methionine requirement than pigs, for example. Methionine is traditionally supplemented in poultry feed in the form of synthetically produced DL-methionine. However, the body can only utilize the L optical isomers. In the case of methionine, however, it is able to convert the D isomer into the L form. L-methionine produced by fermentation is now also available. This raises the question of whether there is a difference in the biological efficiency of the various sources of methionine, especially when used in ovo. Another influencing factor may be differences in production and metabolic intensity between genotypes (hybrids, breeds). That is why we decided to include the Hungarian fawn-colored hen maintained in the university's gene preservation program in our study, in addition to the intensive (TETRA-SL) laying hybrid, explained Csaba Szabó.
The head of the department said that the hypothesis of their study was that L-Met injected into the amnion of the chicken, inside the fetal membrane, improves intestinal development and integrity and enhances the health of the intestinal system better than DL-methionine. Their assumption was that the two genotypes – the laying hybrid and the fawn-coloured Hungarian hen – would react differently to the injected Met sources.
- Our test results suggest that the in ovo application of DL- and L-methionine improved intestinal morphological development in both genotypes, but DL-methionine appears to be more effective. At the same time, both methionine sources had a similar effect on the expression of genes related to intestinal integrity, antioxidant systems, immune response, and growth. The fawn-coloured Hungarian chickens have better antioxidant status and intestinal integrity, while the TETRA SL chickens grow faster and have a stronger immune system, according to the research results presented by the associate professor at the Faculty of Agriculture, Food Science and Environmental Management.
The research conducted by the university's experts confirmed that the in supplementation of methionine also has a positive effect on laying genotypes and that native breeds have valuable characteristics, making their gene preservation an important task.
"I believe we have succeeded in expanding our knowledge of in ovo feeding. It is a particular pleasure and honor that such a prestigious scientific journal as Animal Nutrition has accepted our manuscript. We are currently working on a university proof of concept project involving several faculties and departments, to which the results of this research will also contribute, added Csaba Szabó.
The study is available at the following link.
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