Supplementing advanced chelated trace minerals beyond recommended inorganic levels improve growth performance and physiological stress responses in broiler chickens under heat stress.

Background: Organic trace minerals (TM) offer potential benefits for poultry health and productivity; however, their effectiveness under heat stress (HS) conditions is not well characterized. This study aimed to evaluate the effects of supplementing broiler diets with an advanced chelate-based trace mineral complex (ATMC) under cyclic HS conditions.

Methods: A total of 600 one-day-old Ross 308 broilers were randomly assigned to five dietary treatment groups for a 42-day study: (1) TC, which received a basal diet supplemented with the commercial levels of inorganic trace minerals (ITM) under thermoneutral conditions; (2) HSC, which consisted of a basal diet with the commercial ITM levels under heat stress; (3) ITM+ATMC12.5; (4) ITM+ATMC25, where diets were supplemented with 12.5 % and 25 % additional TM from ATMC, respectively, under HS; and (5) ITM125, which included a diet with 125 % of the recommended ITM levels under HS.

Results: The ITM+ATMC25 group exhibited significantly higher weight gain, European Production Efficiency Index, serum T concentration, and duodenal villus height compared to the HSC group, with results comparable to the TC group. Additionally, feed conversion ratio, mortality rate, abdominal fat, liver weight, heterophil-to-lymphocyte ratio, alkaline phosphatase activity, and corticosterone concentration were lower in the TC and ITM+ATMC25 groups compared to the HSC group. The expression levels of heat shock protein (HSP) 70 in the liver and hypothalamus were lower in the TC and ITM+ATMC25 groups, indicating improved stress resilience. Furthermore, hepatic HSP90 expression was downregulated in the TC, ITM+ATMC12.5, and ITM+ATMC25 groups compared to the HSC group.

Conclusion: The results indicate that adding 25 % more TM provided by ATMC than the recommended ITM levels can positively affect growth, intestinal structure, and stress-related physiological responses in broilers exposed to HS.