Diets supplemented with hydroxychloride or a hydroxychloride–organic blend of Cu, Mn, and Zn improve egg production and reduce mineral excretion in post-peak laying hens

This study evaluated the effects of hydroxychloride (HC) and a hydroxychloride–organic (HCO) blend of trace minerals (TM), compared with inorganic sources (INO), on egg production, egg quality, mineral excretion, tissue mineral composition, and fatty liver haemorrhage (FLH) scores in laying hens from 60 to 100 weeks of age (WOA). Four dietary treatments differing in TM source were used: T1, INO TM (100 ppm Mn, 80 ppm Zn, and 12 ppm Cu supplied as inorganic salts); T2, Mn and Zn were reduced by 20 ppm and supplied as HCO; T3, the same dosage as T2 but supplied as HC; and T4, HCO supplied at half the dosage of T2 (HCO-H). A total of 320 hens were allocated to the four treatments, with 8 replicates of 10 birds each. Egg production and feed intake were recorded during 60 to 100 WOA. Egg quality parameters were measured at 60, 68, 80, and 100 WOA. Mineral composition of the tibia, eggshell, liver, and excreta was determined at 100 WOA. Trace mineral source affected egg production rate over 60–100 WOA, with hens fed HCO or HC showing higher production than those fed INO ( P = 0.006). Hens fed HC had higher egg mass than those fed INO or HCO-H ( P = 0.015). Eggshell breaking strength, shell thickness, Haugh unit, and tibia breaking strength were not affected by TM source ( P > 0.05). A TM source × age interaction was observed for shell percentage ( P = 0.002), with higher values in HCO and HC than INO at 100 WOA. As main effects, HC and HCO-H increased eggshell Cu concentration compared with INO ( P = 0.041). Excreta Cu and Zn concentrations were lower in hens fed HCO and HC than in those fed INO, with HCO-H showing the lowest values ( P < 0.05). FLH scores were not affected by the TM source or dose ( P > 0.05). Overall, replacing inorganic TM with HC or HCO improved egg production, and reduced mineral excretion in post-peak laying hen.