Application of traditional and innovative techniques to investigate productive efficiency and related molecular traits in broiler chickens

Improving feed efficiency represents one of the most important challenges that the poultry industry is currently facing since up to 70% of total production costs is given by feeding. It has been reported that biological limits and animal welfare concerns will limit further genetic improvements of feed efficiency in broiler chickens, strengthening the need for a more detailed comprehension of nutritional and metabolic aspects involved in this trait. Therefore, the present PhD program aimed at evaluating nutritional and physiological aspects involved in overall productivity of broiler chickens, with special regard to feed efficiency, combining both traditional and innovative approaches. In the first trial, it has been shown that the adoption of dietary arginine to lysine ratios higher than those currently recommended had a positive effect on feed efficiency. The analysis of plasma and breast muscle metabolites allowed to hypothesize that these improvements might be ascribed to a modulatory effect of arginine on energy and protein metabolism and hence on overall energy homeostasis. In the second study, productive traits and intestinal transcriptomic profile of two fast-growing chicken hybrids, raised in the same environmental conditions and fed the same diet, were evaluated. The results showed that the genotypes exhibited different growth patterns, feeding behavior, and gene expression profile in the ileum mucosa. Transcriptomic analysis revealed enriched gene sets for mitochondria, cellular energy metabolism, and cell structure and integrity in the first genotype, and enriched gene sets for immune system activation and inflammation in the other one. In conclusion, the results obtained combining both traditional and innovative techniques can shed some light on important aspects involved in productive efficiency of broiler chickens which may allow an optimization of productive strategies to efficiently sustain the increasing demand of poultry meat while improving animal welfare, product quality, and environmental sustainability.