This study aimed to determine the viability of sporozoites from Eimeria bovis when exposed to sodium butyrate (SB), monensin (MON), or butyric acid (BA), and to determine the effects of SB on sporozoite invasion of cells in comparison to MON as measured by the damage to a bovine epithelial cell line. To determine viability, isolated sporozoites were suspended in one of four treatments: control (CON) of cell culture medium alone, SB = 0.028 mg/mL suspended in control medium, MON = 0.01 mg/mL suspended in CON, and BA = 0.18 mg/mL suspended in CON. The number of live sporozoites was less for the MON and BA treatments compared to the CON and SB treatments. The number of dead sporozoites was similar regardless of treatment. There was a trend for treatment to affect the percent sporozoite viability. Control, SB and BA treatments were similar, while MON compared to control and SB had decreased percent viability. Results for MON, when compared to BA, were similar for percent viability. Lactate dehydrogenase (LDH) release was used to determine cellular damage to Madin Darby Bovine Kidney (MDBK) cells when exposed to E. bovis sporozoites in vitro. Cells were exposed to similar numbers of sporozoites and treated with: CON, SB = 0.028 mg/mL in control medium, MON = 0.01 mg/mL in control medium. Control LDH result (with sporozoites) was greater than both the SB and MON treatments while the LDH for SB and Mon and cells not exposed to sporozoites were similar. SB and MON were both shown to decrease cellular damage to MDBK cells as determined by decreased LDH release. SB has the potential to act as an anticoccidial alternative to MON.
Keywords: butyric acid; coccidia; lactate dehydrogenase; monensin; sodium butyrate; viability.
Coccidial infections are a significant problem in food animals, including dairy cattle and although there are drug treatments available, these are banned in many countries. Potential alternatives to drugs like monensin include sodium butyrate (SB) and butyric acid (BA). These were evaluated to determine their effect on Eimeria bovis sporozoites in vitro. The number of viable sporozoites was similar between the control medium alone without monensin and SB treatments but reduced in monensin and BA treatments. The percent viable sporozoites were (percent viable is one measure) similar between the control and SB, and BA treatments while reduced in the monensin treatments. However, monensin and BA treatments were similar for percent viable sporozoites. SB and monensin similarly protected cells from damage caused by sporozoites. SB is likely to dissociate to sodium and butyrate as it passes through the digestive tract suggesting that sodium butyrate might be a viable anticoccidial for cattle.
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