Effect of Saccharomyces cerevisiae Association with Threonine on Productive Performance in Broilers

The aim was to evaluate the association of Saccharomyces cerevisiae (Sc) with threonine (T), in broiler diets, on performance, carcass quality and gut histomorphometric variables. One hundred Ross male broilers (1 to 43 days old) were distributed into four treatments D1: basal diet (BD), D2: BD plus 5 g Sc/kg feed, D3: BD plus 30% T and D4: D3 plus 5 g Sc/kg feed. Productive variables measured were: average daily weight gain (ADWG) (g/broiler/day), average daily feed consumption (ADFC) (g/broiler/day), and feed conversion ratio (FCR). Also, were determinate: carcass yield (CY) (%), breast weight (BW) (g), thigh weight (TW) (g) and abdominal fat weight (AFW) (g). Moreover, villus height (VH) (µ), crypt depth (CD) (µ), villus area (VA) (µ2) and VH/CD ratio were measured. Results shown that D4 had higher ADWG than D3 group (P≤0.05) and exhibited the best FCR than D2 and D3 group (P≤0.05). Also, D4 had higher BW than D3 group (P≤0.05) and lower AFW than D1 (P≤0.05). The CY and TW were not affected by additives, BW was higher in D4 than D3 group (P≤0.05) and AF was lower in D4 respect to D1 group (P≤0.05). Probiotics decreased VH/CD ratio respect to control (P≤0.05) and VA increased in D4 respect to D1 group (P≤0.05). Also, D3 and D4 group had higher mucus and increased goblet cells numbers. Conclusion: Scassociate with T increase the productive performance of broiler through the healthy gut. Improvement in productive performance would be generated by a better FCR that could be reflex in more efficient use of nutrient that could be translated in better carcass performance (increase muscle deposition and decrease AFW). A healthy gut would be generate by an increase in VA and decrease VH/CD Ratio that could be reflex in enhancing absorptive function by more mature epithelia. Also, mucosal hypersecretion produced by increased goblet cell number could be protected, being the first line of host defense against invading pathogens.