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ABSTRACT: In a previous study, we demonstrated that a 15% feed restriction (FR) during the first 2 wk after hatch could improve gait in Pekin meat ducks, but did result in reduced breast mass. We hypothesized that feed restriction after day 5 following muscle satellite cell development would allow the full growth of the breast meat. To accomplish this goal, 300 1-day-old ducklings (Maple Leaf Farms Inc.) were randomly allocated to 1 of the 3 groups (n = 4 pens, 25 ducks per pen): (1) Control group fed to ad libitum; (2) 85% daily feed intake from days 1 to 14 (FR 85% 1–14); 85% daily feed intake from days 5 to 14 (FR 85% 5–14). All ducks were vaccinated with inactivated Salmonella enteritidis on day 14 and boosted on day 26. The FR 85% 5–14 did show similar production standards to controls, and improved gait characteristics (P < 0.05). To determine if the partial feed restriction would have an impact on intestinal epithelial tight junction integrity, we treated ducks on days 7, 14, 21, 28, and 35 with 8.32 mg/kg FITC-d in water per os and blood samples were obtained via the tibial vein 1 h later. Serum samples were analyzed for presence and quantification of FITC-d. Feed restriction elicited a significant increase in FITC-d permeability at all points of evaluation. Anti-S. enteritidis specific IgY responses were assessed by ELISA from serum collected at 14 D, 28 D, and 35 D. Although all ducks showed an increase humoral immune response to the S. enteritidis, both feed restricted groups showed reduced IgY production compared to ad lib controls. Our data suggest that although the FR 5–14 feed restriction paradigm may reduce gait abnormalities without affecting production rates, some challenges exist due to increased gut leakiness or decreased acquired immune activity. Future studies will look at altering the feed restriction milieu to ameliorate these challenges.

SUMMARY: Like other poultry species, Pekin ducks may develop gait abnormalities due to increased muscle growth relative to the skeletal system. Previous studies have shown that Pekin leg bones grow exponentially in terms of mineral deposition during the first 2 wk of life. Therefore, we hypothesized that a slight food restriction (FR) during that time would reduce muscle mass development sufficiently to allow the skeletal system to more fully develop. Our primary goal was to determine if FR could occur without increasing the time to market weight. To obtain this goal, ducks were provided either 65% (FR65) or 85% (FR85) of the control ducks daily feed intake. Food restricted ducks had lower (P < 0.05) body weights than controls at days 7 and 14. After day 14, when all ducks were fed ad libitum (ad libitum), food restricted ducks ate significantly (P < 0.01) more feed per day than control ducks and subsequently gained body weight at an increased rate. By day 35 there were no significant differences in body weight between FR85 and controls, however both FR groups showed reduced (P < 0.05) breast mass compared to controls. Qualitative assessment of gait also suggested that FR ducks had more uniform leg conformation and gait then did the control ducks and did not show any biological signs of reduced welfare. These data suggest that a slight FR is possible without adding time to market and this paradigm might reduce the occurrence of lameness in growing ducks.