Chemical composition and standardized ileal digestibility of protein and amino acids from blue mussel, starfish, and fish silage in pigs

Mussels cultured on lines for nine months and harvested in March were boiled to removeshells and processed into a dry meal or a silage acidified by formic acid. Starfish mealwas prepared from starfish caught in May, and a starfish juice fraction was obtained bypressing fresh starfish. Commercial fish silage from farmed salmon was also included in theexperiment. The standardized ileal digestibility (SID) of crude protein (CP) and amino acids(AA) was evaluated in a Latin square design with pigs (initial weight 39.3 kg) fitted with asimple T-cannula in the terminal ileum. Diets contained 131–162 g CP/kg and 5 g chromicoxide/kg. Endogenous losses of protein and AA were estimated by feeding an N-free diet.On a dry matter (DM) basis, mussel meal contained 605 g, mussel silage 575 g, starfish meal700 g, starfish juice 393 g, and fish silage 776 g CP/kg. The ratio of AA to CP ranged from0.83 to 0.87. The content of crude fat was high in the mussel products (157–161 g/kg DM),and the starfish meal and juice were high in ash (203 and 474 g/kg DM) with one-fourthbeing calcium. The AID of CP was 0.74, 0.81, 0.70, and 0.61 for mussel meal, mussel silage,starfish meal, and fish silage. The SID of CP was 0.83, 0.87, 0.80, and 0.68 for mussel meal,mussel silage, starfish meal, and fish silage. For both CP and AA digestibility, the lowest(P<0.05) was found in fish silage and the highest (P<0.05) in mussel silage. In conclusion,both mussel and starfish products showed chemical characteristics arguing for their use asfeedstuffs in pig diets. Processing into silage rather than meal increased the SID of CP andAA, and both mussel products and starfish meal had greater SID compared to commercialfish silage.