# Evaluation of Non-Encapsulated and Microencapsulated Lactic Acid Bacteria
## 4 Discussion  
Based on phenotypical identification, some characteristics from some identified strains (IBNA 29, 33, 41, 48, 50, 51, 56, 57, 61) are reported in other studies (32,33). To make a good selection of a bacterial strain to use as source of probiotic, it is necessary to provide preliminary in vitro screening by simulated of harvested conditions such as the high acidity of the stomach and high concentration of bile salts in the proximal intestine to ensure their safety (34). LAB are indigenous microorganisms and a significant part of chicken GIT (35). Considered dominant colonies of the small intestine and colon, LABs make an important contribution to balancing the intestinal animal microflora (36). Furthermore, in poultry, administration of probiotics based on _Lactobacillus_ spp. improves feed digestion, nutrient uptake, and growth performance (37,38). The low pH resistance is one of the major probiotic selection factors, involving a reduction in the bacterial population at proventriculars and gizzard broiler chicks' area (38). Figure 2: The storage stability of _Lactobacillus_ (_L. salivarius_ IBNA 33, _L. salivarius_ IBNA 41, _L. acidophilus_ IBNA 64) powders during 62 days at room temperature (25 \({}^{\circ}\)C). Data are represented as means \(\pm\) standard error of means (SEM) of three independent experiments. Parameters such as enzymes, high oxygen pressure, and bile salts are responsible for the reduction of microbial concentration, comparatively with the small and large intestine where the conditions are satisfactory for the growth of diverse bacteria [35]. Cecum and ileum areas are favorable for bacterial growth and have a concentration between 10\({}^{7}\)-10\({}^{11}\) bacteria per gram intestinal content [32; 33; 39]. The level of bacteria can change with animal age, environmental factors, and type of diet. Usually, the probiotics are administered in feed, water, or orally; they must have the ability to resist passage through the low pH of the gastric juice in the stomach and bile salts in the small intestine [5]. Based on the in vitro properties, the selected strains were tested on their tolerance to unfavorable conditions [40]. The pH and bile tolerance were evaluated for 3 h to predict the survival of the probiotic [40]. Interestingly, even though 16S \({}_{r}\)RNA identification presented the same phenotypical profile, the isolates strains had different growth rates in response to pH and bile salt. As a condition, a probiotic bacteria needs to resist the passage through the stomach, where 1.5 to 2.0 pH can be found, and into the intestinal tract [41]. In general, when evaluating the potential use of LAB as a probiotic, it is important to test their ability to tolerate bile salts [42], and from six candidates, only four strains survived in 0.3% concentration (Table 4). There are three types of hemolysis, which are alpha, beta, and gamma hemolysis. To be safe for administration, the probiotics strains are necessary to be nonhemolytic (alpha hemolysis) [43]. In our trial, all isolates were alpha hemolytic. All selected isolates were resistant to gentamicin, limomycin, enrofloxacin, and streptomycin, with a susceptibility to amoxicillin, vancomycin, chloramphenicol, and clindamycin. These results are in agreement with those of [PERSON] et al. [42]. In line with [PERSON] et al. [44], who found that LAB isolated from broiler faces were found to be sensitive to penicillin and amoxicillin and resistant to ciprofloxacin and tetracycline, in our study IBNA 29, IBNA 33, and IBNA 41 showed sensitivity to kanamycin, while IBNA 26, IBNA 64, and IBNA 37 present resistance. Spray drying is an effective technique for the microencapsulation of probiotic bacteria such as lactic acid bacteria and sporulated bacilli, ensuring stability and viability during storage conditions compared to free bacteria [45]. Before microencapsulation, the viability of _Lactobacillus_ strains (IBNA 33, IBNA 41, and IBNA 64) was 10\({}^{8}\)-10\({}^{10}\) CFU/mL. This finding is affirmed by [PERSON] et al.