Effect of dietary boron on immune function in growing beef steers.
Thirty-six Angus and Angus x Simmental cross steers (initial BW 269.5 +/- 22.3 kg) were used to determine the effects of dietary boron (B) on performance and immune function. Steers were fed on one of the three dietary treatments: (i) control (no supplemental B; 7.2 mg B/kg DM), (ii) 5 mg supplemental B/kg DM and (iii) 50 mg supplemental B/kg DM, from sodium borate for 78 days. Supplementation of dietary B had no effect on body weight (BW) gain, feed intake or gain:feed during the study. Jugular blood samples were collected prior to feeding on days 28, 63 and 77 for plasma-B analysis. Supplementation of dietary B increased (p < 0.001) plasma B-concentration in a dose-responsive manner. Furthermore, plasma B-concentration was correlated (p < 0.001; R(2) = 0. 95) to daily B-intake (mg B/day). Jugular blood was also collected, from an equal number of steers from each treatment, on day 42 or 44 for determination of in vitro production of interferon-gamma and tumour necrosis factor-alpha from isolated monocytes and assessment of lymphocyte proliferation. Dietary B did not affect T- or B-lymphocyte proliferation or in vitro cytokine production from monocytes. On day 49 of the study, the humoral immune response was assessed by i.m. injection of a 25% pig red blood cell (PRBC) solution for determination of anti-PRBC IgG and IgM titre responses. Boron-supplemented steers had greater (p = 0.035) anti-PRBC IgG titres than controls on day 7 but not on day 14 or 21 post-injection. Anti-PRBC IgM titres did not differ throughout the sampling period. Results from this study indicate that supplemental B had minimal effects on immune function and did not affect performance of growing steers.
Department of Animal Science, North Carolina State University, Raleigh, NC 27695-7621, USA.
R S
RS
Fry
K E
KE
Lloyd
S K
SK
Jacobi
P D
PD
Siciliano
W P
WP
Robarge
J W
JW
Spears
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001895:Boron / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002417:Cattle / Q000254:growth & development* / Q000276:immunology*; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D008297:Male; D010835:Phytohemagglutinins / Q000276:immunology; D013997:Time Factors; D015430:Weight Gain
D010835:Phytohemagglutinins; D001895:Boron