Fig. 3: The impact of an α-lactalbumin-enriched formula on systemic tryptophan levels on Day 16.

A Free tryptophan concentrations and percentage of free tryptophan in serum derived from arterial blood collected via cardiac puncture at necropsy. B Tryptophan levels in serum (from arterial blood), liver, brain, and urine. A, B Differences between the SF group and one of the formula-fed groups were evaluated using ANOVA followed by Tukey HSD post-hoc tests on generalized log-transformed data, accounting for litter effects in the model. Similarly, differences between the ALAC and WPI groups were assessed using ANOVA on generalized log-transformed data. For serum and liver data, both formula volume, postprandial time, and litter effect were included as factors in the model. For liver, brain, and urine, only the litter effect was accounted for. C Tryptophan to other large neutral amino acids (Tryptophan:LNAA) in the diet, serum, liver, and brain. Group differences were evaluated using a Mann–Whitney U test. Data are represented as mean ± SEM. *p < 0.05, #p < 0.1. PFC prefrontal cortex.