Background: The objective was to study the effect of hydroxychloride trace minerals (HTM) on growth performance, carcass quality and gut microbiota of broiler chickens in comparison to sulphate trace minerals (STM). In total 1440 male Ross 308 day-old chicks were divided over 12 replicate pens with 30 birds each per treatment. Four different treatments were tested according to a 2×2 factorial study design, where the animals received a three phase diet containing either inorganic Zn from sulphates or Zn from HTM in high (80 ppm Zn) or low Zn dosage (20 ppm Zn). In all treatments 15 ppm Cu was added from the same mineral source as the Zn. Body weight and feed intake were measured on day 0, 10, 27 and 34, while carcass and breast meat yields were measured at the end of the study (day 34). In addition, high-throughput sequencing analysis was performed in digesta samples from ileum and cecum to study the gut microbiome (day 34).
Results: The results showed an improved (P<0.05) body weight of broiler chickens fed HTM, regardless of Zn level, on day 27, while on day 34 this effect remained as a tendency (P= 0.0542). In the overall study period, birds fed HTM had a higher (P<0.05) average daily gain and average daily feed intake when compared to birds fed STM. The mineral source did not affect the carcass characteristics, however, feeding 80 ppm Zn resulted in a significantly higher (P=0.0171) breast meat yield, regardless of source. High-throughput sequencing analysis of the microbiota revealed a higher microbial diversity in the ileum and cecum of HTM fed birds compared to STM fed birds. Taxonomical differences were mainly found in the cecum, specifically between the group fed high and low Zn levels from HTM. This is in line with the mineral contents observed in the cecal digesta. Comparing both groups fed 80 ppm Zn, the HTM group had more Streptococcaceae, Streptococcus, Clostridia, Weissella and Leuconostocaceae compared to the STM group.
Conclusions: HTM improved growth performance of the birds; and the source and level of Zn modulated the gut microbiota communities in broilers differentially.