Location: Dale Bumpers Small Farms Research CenterTitle: Changes in concentrations of trace minerals in lambs fed sericea lespedeza leaf meal pellets with or without dietary sodium molybdate Author
|Acharya, Mohan - University Of Arkansas|
|Coffey, Ken - University Of Arkansas|
|Kegley, Elizabeth - University Of Arkansas|
|Miller, James - Louisiana State University|
|Welborn, Matt - Louisiana State University|
|Terrill, Thomas - Fort Valley State University|
|Mosjidis, Jorge - Auburn University|
|Rosenkrans, Charles - University Of Arkansas|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2016
Publication Date: 4/15/2016
Citation: Acharya, M., Burke, J.M., Coffey, K., Kegley, E., Miller, J., Wood, E.L., Welborn, M.G., Terrill, T., Mosjidis, J., Rosenkrans, C. 2016. Changes in concentrations of trace minerals in lambs fed sericea lespedeza leaf meal pellets with or without dietary sodium molybdate. Journal of Animal Science. 94:1592-1599.
Interpretive Summary: Sericea lespedeza (SL) is a legume rich in condensed tannins that can be grazed or fed to small ruminants for parasite control. Condensed tannins, a secondary plant compound in SL, may lead to unintended consequences such as changes in production. Scientists at ARS in Booneville and Fayetteville, AR, the University of Arkansas, Louisiana State University and Fort Valley University determined that there were significant differences in trace minerals in serum and liver between control and SL fed lambs. Many of these trace minerals are important in enzyme complexes that could be important to growth, reproduction, and the immune system, and farmers who choose to feed SL should offer a good trace mineral supplement to sheep and goats to minimize potential deficiencies. The results are important to farmers and extension specialists to build strategies to aid in the control of parasites of small ruminants, and scientists aiming to understand the effects of condensed tannins on the animal.
Technical Abstract: Prolonged feeding of sericea lespedeza (SL; Lespedeza cuneata) previously led to reduced serum concentrations of molybdenum (Mo), a co-factor in an enzyme complex that may be involved in weight gain. The objective of this study was to determine the effect of Mo supplementation on changes in serum, fecal, urine and liver concentrations of trace minerals in lambs fed SL leaf meal pellets. Thirty ram lambs weaned in May (84 ± 1.5 d of age; 27 ± 1.1 kg; D 0) were blocked by BW, breed type (full or three-fourths Katahdin) and EBV of parasite resistance, and randomly assigned to be fed 900 g of alfalfa-based supplement (CON; n = 10) or SL-based supplement (n = 20) for 103 d. Supplements were formulated to be isonitrogenous, isocaloric and to meet trace mineral requirements. Within the SL diet, half of the lambs received 490 mg sodium molybdate weekly (SLMO). Serum was collected on d 28, 56, and 103; urine and feces on d 56, and a liver sample by biopsy on d 104 to determine concentrations of trace minerals. Data were analyzed using a mixed model with repeated measures (serum only) and orthogonal contrasts. Serum concentrations of Mo increased in response to the drench and was greatest in SLMO, then CON, and lowest in SL lambs (P < 0.001); no interaction with time was detected. Concentrations of Mo in liver (P < 0.001) and urine (P < 0.001) were similar between CON and SLMO and lower in SL lambs. However, fecal concentrations of Mo were lowest in CON, highest in SLMO and intermediate in SL lambs (P < 0.001). Serum (P < 0.001), liver (P = 0.013), and fecal (P < 0.001) concentrations of zinc were reduced or tended to be reduced in urine (P = 0.056) in both SL and SLMO compared with CON lambs. Serum concentrations of cobalt increased in CON compared with SL and SLMO lambs between d 0 and 56 (and urine and fecal concentrations also higher in CON on d 56, P = 0.027 and P < 0.001, respectively), but all were similar on d 103 (diet × day, P < 0.005) as with concentrations in liver. Serum (P < 0.001), liver (P < 0.001), and fecal (P < 0.001) concentrations of copper were greatest in CON followed by SL then SLMO lambs. Serum concentrations of selenium tended to be reduced in SL compared with CON and SLMO lambs (P = 0.10), were similar in urine (P = 0.16), but concentrations in liver were reduced in SL compared with CON and even more so in SLMO lambs (P < 0.003). Concentrations of iron and manganese were similar among dietary groups in serum, liver, and urine (iron not detected), but fecal concentrations of manganese were lower in SLMO (P = 0.025) and iron lower in SL and SLMO (P < 0.007). While the dietary Mo did increase stores of Mo in the animal and reduced copper, trace minerals associated with metallo-proteins, Mo, copper, selenium, and zinc, were reduced in the liver of SL and/or SLMO fed lambs. These reductions could be associated with the lower weight gains we have previously observed after prolonged feeding of SL.