529 - Late-Breaking: Effects of in Ovo Injection of High Yield Broilers with Nicotinamide Riboside on Pectoralis Major Morphometrics, Muscle Fiber Density, and Mrna Expression

The objective of this study was to determine the effects of in ovo injection of high yield broilers with nicotinamide riboside (NR) on broiler pectoralis major muscle (PMM) development, growth, and mRNA expression. Fertilized Cobb 700 broiler eggs were randomly assigned to 1 of 4 treatments within a 2×2 factorial design with NR dose (DOS; 0 or 2.5 mM) and injection location (LOC; albumen or yolk) as main effects. Eggs were injected with their assigned treatment at d 10 of incubation. Day-15 and -18 embryos and hatched chicks were euthanized, right PMM and muscle fiber morphometric measurements were collected, and left PMM were utilized for mRNA expression analysis of sirtuin-1 and cyclin D1, 2 and 3. There were no LOC×DOS interactions or main effects for d-15 and -18 PMM measurements (P > 0.23). There were LOC×DOS interactions for hatched chick PMM weight and length, and muscle fiber density (P < 0.04). When NR was injected into the albumen, PMM weight decreased (P = 0.02) and length and fiber density were unaffected (P > 0.33), while PMM weight and fiber density increased when NR was injected into the yolk (P < 0.05). There were no LOC×DOS interactions for all genes analyzed for d-15 and 18-embryos (P > 0.23), but NR embryos had greater expression of all genes (P < 0.03) except d-18 cyclin-D2 (P = 0.08). There were LOC×DOS interactions for hatched chick expression of all genes (P < 0.04). There was no difference in sirturin-1 expression when chicks were injected with 0 mM NR, but 2.5-mM yolk chicks had greater expression than 2.5-mM albumen chicks. When NR was injected into the albumen, expression of all cyclins was unaffected (P > 0.08), while expression increased when NR was injected into the yolk (P < 0.01). Increased expression of sirturin-1 and the cyclins may be responsible for NR catalyzed increase in PMM weight and fiber density.