Starfish (Asterias rubens) as feed ingredient for piglets

The effects of including starfish meal (SM) as an alternative protein source in diets for piglets on performance, faeces characteristics and plasma parameters were investigated. Four diets were formulated to contain different protein sources: fish meal (FM), extruded soybean meal (ESBM) and two levels of SM (SM50 and SM100). All diets contained 174.4 g soybean meal/kg feed and were supplemented by up to 166-172 g standardised ileal digestible crude protein/kg feed with either FM, ESBM, SM or a combination giving rise to two SM + ESBM diets with different levels of SM and ESBM. One wk after weaning, 96 pigs with a body weight of 9.6 ± 0.4 kg were housed individually and allocated to one of the four diets (n = 24) and fed ad libitum for a 14 d period. Average daily feed intake (ADFI), average daily gain (ADG) and gain to feed ratio (G:F) were determined. Pigs fed the SM100 diet had a 23-28% lower (P < 0.001) ADG than pigs fed the FM, ESBM and SM50 diets, despite the fact that they ate the same amount of feed. Faeces characteristics were evaluated by scoring during 5 d, and no differences were observed, indicating no effect of the diet on diarrhoea. Blood samples were collected on d 15. Plasma urea nitrogen in SM100 was higher (P < 0.003) than the concentrations in ESBM and SM50 but not FM. Plasma Ca concentration was higher (P < 0.001) in pigs receiving SM100 compared to FM, ESBM and SM50. The opposite was the case with P where the concentration was lower (P < 0.001) in SM100 compared to FM, ESBM and SM50. In conclusion, feeding 50 g SM/kg resulted in a performance equal to pigs fed the control diets. Inclusion of 100 g SM/kg in the diet affected performance negatively due to a wide Ca:P affecting digestibility and absorption of P negatively. Thus, the determining factor for the maximum inclusion level of SM in diets for piglets may be the dietary Ca level and the resulting Ca:P in relation to the nutritional requirements.