Effect of dietary inclusion of Atlantic snow crab, Chionoecetes opilio and Northern pink shrimp, Pandalis borealis processing by-products on nutrient digestibility by juvenile haddock, Melanogrammus aeglefinus L.

A study was conducted to evaluate the effect of dietary inclusion of Atlantic snow crab, Chionoecetes opilio (Crab) and Northern pink shrimp, Pandalis borealis (Shrimp) by-product meals on nutrient digestibility in haddock, Melanogrammus aeglefinus. The study provides coefficients of total tract apparent digestibility (CTTADs) essential for diet formulations aimed at further growth performance and nutrient utilization studies with gadoids using these waste streams as potential replacements for high-cost fish meals and poorly digestible wheat by-products. Organic matter (OM) CTTAD was significantly improved (P=0.005) with Shrimp150 (0.82) relative to the Control (0.79), while Shrimp300 was similar (0.79) (P=1.000). No significant difference in OM CTTAD was found between the Control and Crab150 (P=0.110), Shrimp150 (P=0.473) or Shrimp300 (P=0.144) at an average of 0.80. However, OM CTTAD was significantly reduced (P<0.001) for Crab300 (0.76). Inclusion of Shrimp at 150 g/kg significantly improved (P=0.003) gross energy (GE) CTTAD (0.85 on average) relative to the Control (0.83), while Crab150 (P=0.081), Crab300 (P=0.134) and Shrimp300 (P=0.986) were statistically equal to the Control (average, 0.82). Crude protein (CP) CTTAD of Crab150 (P=0.803) and Shrimp150 (P=0.980) were similar to the Control at an average of 0.90 while Crab300 (P<0.001) and Shrimp300 (P=0.005) were significantly reduced (average 0.86). Dietary inclusion of either Atlantic snow crab or Northern pink shrimp processing by-product meal at 150 g/kg, concomitant with a 50% reduction in wheat middlings and 10% reduction in fish meal, resulted in OM, GE and CP CTTADs equal to or exceeding that of the fish meal-based Control diet.