## 3 Results and Discussion
### Immununoglobulin Content and Lysozyme Activity in Raw Colostrum  
According to our results, IgM represents 86% of the total Igs studied, followed by IgA and IgG with 8 and 6%, respectively, showing a different relative profile compared to human colostrum [21], where IgA was reported as the primary Ig [7], with values that can reach 8.0-9.0 mg/mL [22; 23]. Moreover, it has been widely described in the literature that the Ig content in colostrum is highly dependent on several factors, such as the animal species, the stage of lactation and the time of collection, among others [24]. Since the equine placenta does not allow any antibody transfer, the foal immunity depends entirely on colostrum and milk intake in the first days post-partum [25].  
The enzyme lysozyme, together with other factors including Igs, is one of the most important natural antimicrobial compounds in colostrum and milk, being present in donkey milk in high quantities [26]. In the present study, the lysozyme activity found in donkey colostrum was 3.54 \(\pm\) 0.87 (\(\times 10^{5}\)) U/mL, which is very similar to previously reported  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Treatment** & **Storage Days** & **Total Aerobic Mesophilic** & **Enterobacteriaceae** & **Total Coliforms** \\ \hline \multirow{4}{*}{**Untreated**} & 0 & \textless{}1.0 & \textless{}1.0 & \multirow{4}{*}{\textless{}1.0} \\ \cline{2-4}  & 4 & 6.7 \(\pm\) 0.1 & \textless{}1.0 & \\ \cline{2-4}  & 7 & 5.1 \(\pm\) 0.1 & 3.5 \(\pm\) 0.1 & \\ \cline{2-4}  & 11 & 5.3 \(\pm\) 1.9 & 4.4 \(\pm\) 0.1 & \\ \cline{2-4}  & 18 & 8.0 \(\pm\) 2.5 & 8.2 \(\pm\) 0.1 & \\ \hline \multirow{4}{*}{**TP**} & 0 & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} \\ \cline{2-4}  & 4 & & & \\ \cline{2-4}  & 7 & & & \\ \cline{2-4}  & 11 & & & \\ \cline{2-4}  & 18 & & & \\ \cline{2-4}  & 21 & & & \\ \cline{2-4}  & 28 & & & \\ \cline{2-4}  & 40 & & & \\ \hline \multirow{4}{*}{**400 MPa**} & 0 & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} \\ \cline{2-4}  & 18 & & & \\ \cline{2-4}  & 21 & & & \\ \cline{2-4}  & 28 & & & \\ \cline{2-4}  & 40 & & & \\ \cline{2-4}  & 4 & & & \\ \cline{2-4}  & 550 MPa & 11 & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} & \multirow{4}{*}{\textless{}1.0} \\ \cline{2-4}  & 18 & & & \\ \cline{2-4}  & 21 & & & \\ \cline{2-4}  & 28 & & & \\ \cline{2-4}  & 40 & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Microbial counts in untreated donkey colostrum and after thermal (TP) and high-pressure pasteurization (HPP). Data are presented as log CFU/mL.  
values for donkey colostrum, 1.4-1.2 (\(\times 10^{5}\)) U/mL, at day one of lactation [27], while for donkey milk, the same authors reported a value of 3.4-2.0 (\(\times 10^{4}\)) U/mL at day 60 of lactation, indicating that the amount of lysozyme varies considerably along lactation. These results are very interesting since the higher lysozyme content in donkey colostrum is an advantage to the safety and functionality of the donkey colostrum for increased periods.