Response to dietary supplementation of mixtures of either selected synbiotic, organic acids or essential oils as growth promoters for growing Japanese quails

The present study was aimed to compare the efficacy of natural dietary supplementations (either synbiotics, organic acids or essential oils) in promoting productive performance and health status of growing Japanese quails. In total, 840 unsexed quail chicks aged 14 days, were randomly distributed into four groups of 210 birds in seven replicates, 30 birds each. The first group was fed un-supplemented control diet, the other groups were supplemented with: i) a mixture of live Saccharomyces cerevisiae, Bacillus spp. and their cell wall extracts, in addition to beta-glucan and mannan-oligosaccharides as synbiotics; ii) a mixture of formic and propionic acids as organic acids; or iii) a mixture of carvacrol, cinnamaldehyde and capsicum oleoresin as essential oils; at a level of 1, 0.5 and 0.15 g per kg diet, respectively. It was indicated that birds fed diets supplemented with either examined mixture of essential oils or organic acids had significantly higher body weight and better feed conversion ratio than the control group (by 5.4 and 4.9%, and 10.3 and 8.8%, respectively). It was also revealed that all studied growth promoters significantly increased the abdominal fat percentage. Both groups treated with mixture of either essential oils or organic acids recorded significantly higher villi height and width with lower total bacterial count and Escherichia coli enumeration than the control one. In conclusion, both examined mixtures of either essential oils (with carvacrol, cinnamaldehyde and capsicum oleoresin) or organic acids (formic and propionic acids) could be used in quail diets as organic growth promoters as they enhance growth performance by improving blood parameters and gut health status.