Abstract
With a growing increase in further processing of poultry, there has been an increased interest in factors, including feed additives, that may improve broiler performance, increase growth, and influence dressing percentage. Mammalian target of rapamycin (mTOR) is known to play vital roles in protein synthesis; mTOR controls the anabolic and catabolic signaling of skeletal muscle mass, resulting in the modulation of muscle hypertrophy. Exogenous phosphatidic acid (PA) can stimulate the mTOR pathway via its activation of the substrate S6 kinase. A study with 648 Cobb 500 male broilers, housed in 36 floor pens (1.11 m2) from 1 to 42 days of age was conducted to evaluate the timing of PA (Mediator® 50P, Chemi Nutra, Austin, TX, USA) supplementation on the growth performance and carcass yield of broilers. Dietary treatments included T1, Control (CON), T2, 5 mg/bird/day of PA for 42 days (d0−42, PAA); T3, 5 mg/bird/day of PA for 28 days (d15−42, PAGF); and T4, 5 mg/bird/day of PA for 14 days (d29−42, PAF). All birds were weighed on d14, 28, and 42 to obtain BW (body weight), FCR (feed conversion ratio), and MORT (mortality percentage). On d42, eight birds per pen were processed to determine carcass and breast meat yield. No differences were observed in BW at d14 or d28. At d42, birds fed PAA were heavier (3.73 ± 0.02, p < 0.05) than all dietary treatments (3.68 ± 0.02). From d0 to d28, birds fed PAA had the lowest FCR (1.423 ± 0.005, p < 0.05) compared to all dietary treatments (1.441 ± 0.005). From d0 to d42, birds fed PAA and PAGF had a lower FCR (1.545 ± 0.014, p < 0.05) when compared to the CON (1.609 ± 0.013). No differences were observed in MORT between treatments during growout. Increased BW observed in birds fed PAA translated to increased breast fillet weight (0.772 ± 0.009 kg, p < 0.05) when compared to the CON (0.743 ± 0.008 kg). Carcass yields were increased in birds fed PAA (77.48 ± 0.32 kg, p < 0.05) when compared to all dietary treatments (76.24 ± 0.16 kg). Utilizing PA for 42 days increased live weights, improved FCR, increased carcass yield, and increased breast fillet weight at processing. Results from this study indicate that supplementation of PA during all phases of growth may increase the production efficiency of broilers.