The potential activation of calcium sensing receptor by deoxynivalenol contamination in piglets and the effects of vitamin supplements (D, E and C)

Diversification of feed ingredients by adding by-products or low-graded grains is a way to reduce feed cost in pig production. However, this strategy can introduce mycotoxins, especially deoxynivalenol (DON). DON has been showed to induce anorexia, immunomodulation, oxidative stress, and more recently, alterations of calcium (Ca) and phosphorus (P) metabolism. It was thus hypothesised that vitamin D₃, 25-OH-D₃, or vitamin C and E addition can counteract the effects of DON in piglets. A total of 96 piglets were divided into 48 pens of the 9 treatments in 3 x 3 factorial design: control treatments (CON), DON or DON+VitE-C, these three diets were unsupplemented or supplemented with VitD₃ or 25-OH-D₃. After 21 days, piglets were weighted and one per pen received LPS injection as an acute inflammatory reaction 3h prior to euthanasia. Bone mineral content of each piglet was measured with dual-intensity X-ray absorptiometry. Blood samples were taken to assess concentrations for VitD, E and C, P, Ca, antioxidant enzymes. Results showed that, DON or DON+VitE-C had lower average daily feed intake and average daily gain (P<0.001). DON also had higher BMC per kg live body weight (10.27%, P<0.001) than CON, while DON+VitE-C had an intermediate bone mineral content. DON and DON+VitE-C also had lower plasma concentrations of 25-OH-D₃, 1,25-(OH)₂-D₃ and phosphate (P<0.001). The superoxide dismutase activity in intestinal mucosa after LPS injection was reduced in DON and DON-VitE-C piglets, but in unstimulated LPS pigs, the activity was increased only in DON (LPS x DON, P <0.002). However, in intestinal mucosa, DON+VitE-C had lower catalase activity and MDA concentration than CON with intermediary values for DON (P<0.05). The DON induced intestinal and systemic modification of oxidative status and alteration of vitamin D-calciumphosphorus metabolism. More studies are needed to assess the link between these phosphocalcium metabolism changes and DON induced anorexia, including calcium sensing receptor (CaSR) which produces satiety hormones and activates parathormone synthesis. 

Key words: deoxynivalenol, calcium, antioxidant, oxidative stress, vitamin D, bone mineralization.

Published in the proceedings of the Animal Nutrition Conference of Canada 2020. For information on the event, past and future editions, check out https://animalnutritionconference.ca/.