The metabolism of nutrients and potential toxic substances is also species-specific, as is susceptibility to toxic substances. The consequence of this specificity is that experimental data obtained in animal testing cannot be extrapolated with certainty to other animal species. The nutritional and toxicological evaluation must, therefore, be done in all animal species for which the product is destined, i.e., the target species. Table 9 shows digestibility coefficients of a fungal product in two different monogastric species - poultry and pigs. The digestibility of the organic matter, which is close to 80 for pigs, is a mere 24 for chickens.
Protein digestibility differs somewhat less dramatically.
The table suggests that the difference is probably caused by the difference in digestibility of crude fibre. In the final analysis, the metabolizable energy available for chickens is only one-third of that for pigs. When producing SCP products commercially, biological testing must ensure that they comply with the specifications of the product for which approval was originally obtained. If the product is modified after testing, the initial experimental data may no longer be applicable. The final stage of testing should include optimum application of the product in the rations for the animal species that will consume these rations in the countries where the product will be applied.