L-glutamine supplementation reduces gastrointestinal permeability and biomarkers of physiological stress in preweaning Holstein heifer calves

L-glutamine supplementation improves gastrointestinal and immune function in dairy calves during controlled stress challenges. However, it is unknown whether supplementing milk replacer (MR) with preweaning calf health welfare under production conditions. Therefore, the study objective was to evaluate effects of MR on permeability, function, growth performance, postabsorptive metabolic biomarkers, physiological response calves. In 3 repetitions, Holstein heifer (n = 30; 1.5 ± 0.5 d old; 37.1 0.86 kg body weight) were blocked by serum total protein, weight, age, provided (3.8 L/calf per d; 24% CP, 17% fat, 12.5% solids) supplemented (GLN; 10g/kg powder; n 5 calves/repetition) or nonsupplemented (NSMR; calves/repetition). Calves individually housed ad libitum starter grain water access until weaning (56.4 old). At 1 6 wk urinary catheters placed, orally dosed L chromium (Cr)-EDTA. Urine samples collected over a 24-h period for Cr output analysis as an vivo biomarker permeability. Blood 1, 5, 7, 14, 21, 42, 56 measure white blood cell counts, cortisol, insulin, glucose, nonesterified fatty acids, amyloid A, haptoglobin, neutrophil: lymphocyte. Two intervals used statistical analyzes representing greater (P1; 1–3) reduced (P2; 4–8) enteric disease susceptibility. Data analyzed using PROC GLIMMIX SAS 9.4 experimental unit. Overall, GLN versus NSMR Total at age calves, but no differences detected age. Neutrophil: lymphocyte decreased both overall P2 neutrophil counts tended be P2. No treatment average daily feed intake, gain, measurements, scores, therapeutic treatments between summary, permeability biomarkers