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

Authors: CEJA, GUADALUPE - Purdue University; BOERMAN, JACQUELYN - Purdue University; NEVES, RAFAEL - Purdue University; JORGENSEN, MATTHEW - US Department Of Agriculture (USDA); Johnson, Jay

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2023
Publication Date: 8/23/2023
Citation: Ceja, G., Boerman, J.P., Neves, R.C., Jorgensen, M.W., Johnson, J.S. 2023. L-glutamine supplementation reduces gastrointestinal permeability and biomarkers of physiological stress in preweaning Holstein heifer calves. Journal of Dairy Science. https://doi.org/10.3168/jds.2023-23334.
DOI: https://doi.org/10.3168/jds.2023-23334

Interpretive Summary: Intestinal disease is prevalent in preweaned dairy calves and is a common cause of morbidity and mortality in the first 3-weeks of life. As such, it is a significant economic, animal health, and welfare concern and there is a critical need to identify prevention strategies to improve the overall health and welfare of preweaned dairy calves. In the present study, it was determined that supplementing preweaned calf milk replacer with 1.0% L-glutamine (dry matter basis) improved measures of intestinal health, reduced measures of physiological stress, and improved measures of immune function. Therefore, L-glutamine supplementation in milk replacer may be a viable solution to reduce the prevalence of intestinal disease and improve overall health and welfare in preweaned dairy calves.

Technical Abstract: L-glutamine supplementation improves biomarkers of intestinal permeability and immune function in dairy calves during controlled immune and stress challenges. However, it is unknown whether supplementing milk replacer (MR) with L-glutamine improves intestinal permeability, immune function, growth performance, post-absorptive metabolic biomarkers, or reduces biomarkers of physiological stress in preweaned dairy calves. In three repetitions, Holstein heifer calves [N = 30; 1.5 ± 0.5 days old; 37.1 ± 0.86 kg body weight] were blocked by serum total protein, body weight, and age, and provided MR (3.8 L/calf/day; 24% CP, 17% fat, 12.5% solids) supplemented with L-glutamine (GLN; 10g/kg MR powder; n = 5 calves/repetition) or non-supplemented (NS; n = 5 calves/repetition). Calves were individually housed with ad libitum starter grain and water access until weaning (56.4 ± 0.5 days old). At 1 and 6 weeks of age, urinary catheters were placed, and calves were orally dosed with 1 L chromium (Cr)-ethylenediaminetetraacetic acid. Urine samples were collected over a 24-hr period for Cr output analysis as an in vivo biomarker of intestinal permeability. Blood was collected on study days 1, 5, 7, 14, 21, 42, and 56 to measure white blood cell counts, cortisol, insulin, glucose, non-esterified fatty acids, serum amyloid A, haptoglobin, and neutrophil: lymphocyte. Two study periods were identified representing greater (P1; weeks 1-3) and reduced (P2; weeks 4-8) enteric disease susceptibility. Data were analyzed using PROC GLIMMIX in SAS 9.4 with calf as the experimental unit. Overall, total urinary Cr output was reduced in GLN versus NS calves. Total Cr output was reduced at 1 week of age in GLN versus NS calves, but no differences were detected at 6 weeks of age. The neutrophil: lymphocyte was decreased overall and during P2 in GLN versus NS calves, and neutrophil count tended to be reduced in GLN versus NS calves during P2. There were no MR treatment differences for ADFI, ADG, body measurements, post-absorptive metabolic biomarkers, disease scores, and therapeutic treatments between GLN and NS calves. In summary, L-glutamine supplementation reduced intestinal permeability and biomarkers of physiological stress in preweaned Holstein heifer calves.