Ghazaleh Keshavarzbahaghighat | ALES Graduate Seminar

Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree. This is an ALES MSc Final Exam Seminar by Ghazaleh Keshavarzbahaghighat. This seminar is open to the general public to attend.

Zoom Link: https://ualberta-ca.zoom.us/j/93131037048

MSc with Dr. Anne Laarman     

Thesis Topic: Improving Passive Immunity Transfer Window through Nutritional Supplementation of Colostrum

Abstract:

Newborn calves are agammaglobulinemic at birth, relying entirely on passive immunity transfer to obtain essential immunoglobulins to improve overall health. Passive immunity transfer lasts approximately 24h, when immature, macromolecule-absorbing enterocytes are replaced by mature enterocytes, which cannot absorb macromolecules. Whether enterocyte maturation can be altered by bioactive compounds that impact cell cycle and maturation is unknown. This study investigated the effects of colostrum supplementation with butyrate and monensin on intestinal cell maturation and turnover, and the efficacy of IgG absorption in newborn dairy calves. Newborn bull calves (n = 36) were assigned to four groups: a baseline group, not fed colostrum and slaughtered at 1 hour of life (BASE); and three treatment groups which were fed 1.3 L of colostrum including 150 mg/kg BW of acetaminophen at 1 hour of life and slaughtered at 12 hours of life. Within the three treatment groups, colostrum was either unsupplemented (CON), supplemented with butyrate at an inclusion rate of 2.5% w/v (BUT), or supplemented with monensin at a dosage of 1 mg/kg BW (MON). The osmolality of all colostrum treatments was adjusted to 400 mOsm/kg using saline solution, with a total volume of 3 L administered to all calves. Following catheterization, blood samples were collected every 30 minutes from 2 to 8 hours of life, and then hourly from 8 to 12 hours of life. At harvest, blood was sampled, and tissues and mucus from duodenum, proximal jejunum, distal jejunum, and ileum as well as liver tissue samples, were collected for analysis of serum IgG and acetaminophen, which was used to calculate abomasal emptying rates. Liver tissues were analyzed for glycogen concentration. Gastrointestinal tissues were analyzed for villi length and crypt depth, and enterocyte differentiation was evaluated by measuring lactase enzyme activity, a key brush border enzyme. No differences were observed among the MON, CON, and BUT groups for IgG concentration (P = 0.60). Villi-to-crypt ratio in all the treatments was lower than BASE (P < 0.01). The villi height differed by treatment and tissue (P < 0.01), where both MON and BUT had shorter villi than CON (P < 0.01) in the duodenum. Crypt depth for BUT was higher than MON (P = 0.01) in the distal jejunum. In ileum, crypt depth in BUT and MON was higher than CON (P < 0.01 and P = 0.04, respectively). The BASE group showed the highest liver glycogen levels (P < 0.01) while no differences were observed among the other treatment groups, BUT versus CON (P = 0.28), BUT versus MON (P = 0.83), and CON versus MON (P = 0.77). MON group had higher cumulative acetaminophen recovery (P = 0.02). No differences were observed among the MON, CON, and BUT groups in abomasal emptying rate (P = 0.44). Lactase activity did not differ in the duodenum (P = 0.65), proximal jejunum (P = 0.35), or distal jejunum (P = 0.06). In the ileum, BASE group showed lower lactase activity than BUT (P < 0.01) and CON (P < 0.01), and BUT showed higher lactase activity than MON (P < 0.01). Monensin shifted the intestinal epithelium toward a less mature state, in contrast to butyrate. While it did not enhance passive immunity transfer at 12 hours, it may still exert delayed positive effects with longer exposure.