Abstract
Background:
In modern industrial poultry farming practices, forced molting has not lost its importance and is widely employed in commercial poultry production. However, to effectively apply this technology, a more detailed understanding of the physiological processes that occur during molting is necessary. Moreover, new methods are needed to help the bird recover from molting, minimize stress, promote recovery, and ultimately increase productivity in the next cycle.

Aim:
The objective of this study was to investigate the antioxidant status of laying hens during the molting period and to assess the effectiveness of combining probiotics with trace elements in alleviating postmolting syndrome in birds.

Methods:
The study was conducted on a total of 250 Hisex-Brown laying hens at the age of 469 days, which were randomly divided into groups: a premolting group that received the basic diet without induced molting; a molting group that underwent a 10-day fasting period; a postmolting group that underwent molting with gradual feeding restoration; a control production group (n=50) that underwent molting with gradual feeding restoration; after the end of molting, the laying hens received the basic diet; an experimental production group that underwent molting with gradual feeding restoration and then received acidophilus, bifidobacteria, and chelated trace elements during 30 days. Blood samples were collected from the wing veins of laying hens in each group to assess the antioxidant status of the birds using colorimetric assays.

Results:
Total superoxide dismutase activity increased by 33% (p=0.04), whereas catalase activity increased by 15% (p=0.02), concurrently with a 13% increase in malonic dialdehyde content, in laying hens undergoing forced molting (fasting period), in blood serum, compared with non-molted birds. By the end of the molting period, the activities of these enzymes had decreased, and the malonic dialdehyde content was 31% higher than the control values (p=0.002). Following molting, treatment with a probiotic mixture (L. acidophilum and В. adolescentis) and trace elements (Cu, Mn, Fe, Se, and Zn) increased antioxidant capacity, accompanied by a 24% increase in superoxide dismutase activity (p=0.02), a 25% increase in glutathione peroxidase activity (p=0.05), and a 14% decrease in malonic dialdehyde levels (p=0.003).

Conclusion:
The present study provides convincing evidence for the use of a combined supplement containing L. acidophilum and В. adolescentis with trace elements during the postmolting period to improve antioxidant status.

Key words: Poultry, Forced molting, Stress, Antioxidant status, Probiotics, Trace elements.