Efficacy of the spray-drying treatment to inactivate the bovine leukemia virus in bovine colostrum

Abstract

Previous studies have shown the presence of bovine leukemia virus (BLV) in colostrum and milk of naturally infected cows. The relationship between virus or provirus and specific antibodies in these secretions is particular to each infected cow and will probably determine whether the consumption of colostrum or milk from these naturally infected dams provides an infective or a protective effect in recipient calves. Our recent findings suggest that this issue is a key point in BLV transmission in very young calves. Based on this, the aim of the present study was to determine the effect of the spray-drying treatment of colostrum on BLV infectivity. The treatment was done on scale-down conditions, using fresh colostrum from BLV-negative cows spiked with infective BLV. Residual infectivity was tested in susceptible lambs. Lambs inoculated with colostrum spiked with BLV-infected cells or cell-free BLV showed evidence of infection 60 d after inoculation, whereas none of the lambs inoculated with spraydried colostrum showed evidence of infection 60 d after inoculation. These results provide direct evidence that the experimental spray-drying process used in this study was effective in inactivating infectious BLV in colostrum. These findings suggest that the risk for BLV transmission could be reduced if milk and colostrum were treated by spray-drying prior to consumption in dairy facilities. The effect of spray-drying on the functional properties and stability of the antibodies present in colostrum under long-term storage should be further investigated.

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

“…Moreover, our group has recently reported that the experimental spray-drying process is effective in inactivating infectious BLV in colostrum. In that study, we inoculated susceptible lambs with treated (spry-dried) or untreated colostrum spiked with BLV-infected cells and found that lambs that had received the untreated colostrum showed evidence of infection 60 days post-inoculation ( 75 ).…”

“…Pasteurization of milk is another feasible strategy to ensure the inactivation of BLV without significantly altering the concentration of immunoglobulins or their physiological activities ( 75 – 77 ). It has been reported that sheep inoculated with milk experimentally contaminated with BLV and treated by a simulated high-temperature short-time (HT ST) pasteurization procedure do not become infected or develop tumors ( 75 , 77 ). In addition, HT ST pasteurization has the additional benefit of helping to limit the spread of Johne's disease and other pathogens ( 78 ).…”

Insights into the Research Trends on Bovine Colostrum: Beneficial Health Perspectives with Special Reference to Manufacturing of Functional Foods and Feed Supplements

“…Lactoferrin is lost throughout a temperature range of 65–95 °C as time and temperature increase [ 45 ]. Additionally, spray drying is efficient in suppressing the transmission of the bovine leukemia virus (BLV) in milk and colostrum to some extent [ 46 ].…”

Transfer and persistence of bovine immunoglobulins in lambs fed a colostrum replacer

“…However, bovine colostrum may be contaminated with pathogens, including rotavirus, Cryptosporidium , bovine leukosis virus or Mycobacterium avium subsp. paratuberculosis , thus posing an infection risk 12–15 …”

“…paratuberculosis, thus posing an infection risk. [12][13][14][15] Colostrum replacers are synthetic feed products designed to completely replace maternal colostrum. 16 However, few studies have analysed the impact of feeding colostrum replacers to lambs.…”