Based on the phosphorus mass balance results, it can be derived
that there in theory would have been no discharge of dissolved
waste TP at a PPC inclusion level of 72%, equal to a pea:horsebean:
rapeseed inclusion ratio of approximately 28:26:17 (Fig. 3). Such a
high inclusion level would almost certainly not be able to fulfill the
phosphorus requirement of the fish. There thus appears to be a minimum
metabolic requirement and concomitant excretion of phosphorus
below the dietary breakpoint value (Dalsgaard and Pedersen,
2011), suggesting that fish fed available dietary phosphorus concentrations
below the breakpoint value will be forced to utilize intrinsic
phosphorous reserves. Furthermore, the amino acid requirement of
the fish would almost certainly not be satisfied at this high inclusion
level as observed by Lunger et al. (2006, 2007) when replacing more
than 40% fish meal protein with organic protein in feed for cobia.