Table 1 Eligibility criteria

1. ICU patients in the acute phase of critical illness after gastrointestinal oncological surgery

2. Age ≥18 years

3. Central venous access available for continuous infusion of the study drugs

4. Admitted to the ICU during the previous 24 h with a minimum expected ICU stay of ≥5 days

5. Sequential Organ Failure Assessment (SOFA) score ≥ 2

6. Written informed consent from the patient or the patient’s legal representative

Exclusions associated with nutritional status:

1. Received parenteral nutrition within 7 days before randomisation

2. Expected to receive ≥20% of energy via supplemental EN and/or non-nutritional sources (e.g. glucose solution for drug dilution or lipids from propofol) during the first 3 nutritional treatment days

3. Inability to initiate EN prior to randomization

4. Body mass index <17 kg/m² or >35 kg/m²

5. Any congenital errors of amino acid metabolism

Exclusions associated with comorbidities and allergies:

6. Known hypersensitivity to fish, egg, soybean proteins, peanut proteins, or to any of the active substances or excipients contained in SPN

7. Known hypersensitivity to milk protein or to any other substance contained in SPN

8. Hemophagocytic syndrome

9. Known history of HIV, hepatitis B and/or C

10. Any severe, persistent blood coagulation disorder with uncontrolled bleeding

Concomitant therapy exclusions:

11. Chronic maintenance therapy with systemic glucocorticoid steroids (hydrocortisone >0.3 mg/kg/d).

12. Concomitant administration of chemotherapy

13. Administration of growth hormone and teduglutide within the previous 4 weeks

Laboratory exclusions:

14. Hypertriglyceridemia characterised by serum triglyceride levels >4 mmol/L (>350 mg/dL)

15. Treatment-refractory, clinically significant major abnormality in the serum concentration of any electrolyte (sodium, potassium, magnesium, total calcium, chloride, inorganic phosphate)

16. Acute liver failure with encephalopathy, including intoxication (e.g. paracetamol, death cap, golden chain) and/or liver enzymes (aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transferase) or bilirubin exceeding 10 x upper limit normal

Other exclusions:

17. Chronic liver failure (Child-Pugh scale B or C), e.g. secondary to drug or alcohol abuse

18. Participation in another interventional clinical trial within the previous 4 weeks

19. Pregnancy or lactation

20. Previous inclusion in the present study

21. Patient unlikely to survive to 6 months due to underlying illness

22. Receiving end-of-life-care