The faecal parameters viz., pH, lactic acid, coliform, and probiotic microbial counts i.e., LAB and Mould in T1, T2, and T3 groups, were determined on 0 and 50th day of study and shown in Table 4.45 and 4.47. Statistically, non-significant effects of probiotics supplementation were found for pH, lactic acid, coliform, LAB, and mould counts. Though the differences were non-significant but pH, coliform and mould counts were recorded higher, in contrast, lactic acid and LAB counts were recorded lower on day 50th in elephants fed with probiotic L. acidophilus (T2) followed by elephants fed with probiotic S. cerevisiae (T3) and then in the control group (T1), respectively. Apparently, on observing the data, the mean values observed lower for pH, coliforms, and mould counts and higher for lactic acid and LAB on the 50th day than the mean values observed on 0 day in all the respective groups. The present study suggests that the trend of decline in lactobacillus count obtained from probiotics fed elephants as compared to those fed the control diet could be implicative of positive health status (Casey et al., 2007).
Fowler (1986) reported that the digestive system, in the case of elephants, was similar to horses. Hence, extrapolations were carried out with regard to the dosing regimen of the Probiotic preparations from the resources used in case of horses. In the present study, the probiotics which contained 1 × 109 colony-forming units /g concentrate of Lactobacillus acidophilus and 1 × 109 colony-forming units /g concentrate of Saccharomyces cerevisiae were given for every 50 kg body weight per day. In this regard, it becomes noteworthy to mention that Weese et al. (2003) used 1×1010 colony forming units per 50 kg body weight per day in a group of horses, pertaining to the Lactobacillus organisms and it was quoted that the consistent intestinal colonization could be achieved only with a high dose.
The relationship between probiotics treatment and low pH conditions in the intestines has been previously reviewed, and some in vitro studies have demonstrated that probiotic bacteria release carboxylic acids such as lactic acid and acetic acid, and have inhibitory effects on the growth and invasive function of E. coli in low pH conditions (Marshall-Jones et al., 2006, Parvez et al., 2006 and Miyazaki et al., 2010). Although supplementation of S. cerevisiae has been reported to prevent acidification of faeces and improve microbial fibrolytic activities induced by a high-fiber or high-starch diet in horses (Medina et al., 2002 and Jouany et al., 2009). In this study, the faecal pH of the probiotics fed elephants showed slight decreasing trend. The maintenance of a lower faecal pH and the elevation in faecal lactic acid concentrations suggest increased enteric populations of lactic acid-producing bacteria. An acidic pH in the intestines of elephants is thought to be detrimental due to the acid sensitivity of fiber-degrading bacteria; however, the fecal pH in all the elephants was within a physiological range during the experiment (Hydock et al, 2014). Therefore, appropriate supplementation of probiotics did not have a negative influence on the gut environment of the elephants.
The findings of the present study indicate that faecal profile of elephants is similar to the horses (Stevens and Hume, 1998) and were also confirmed in elephants (Katole, 2011, Ilmberger et al., 2014, Rungsri et al. (2015, Senthilkumar et al., 2018 and Zhang et al., 2019). Swanson (2002), Swyers et al. (2008), Jounay et al. (2014) and Taran et al. (2015) observed no differences in the numbers of lactic acid bacteria as well as on faecal pH on supplementation of S. cerevisiae in horses. However, highly significant increased in concentration of Saccharomyces cerevisiae strain was seen in the cecum and colon of live yeast supplemented fistulated horses by Jounay et al. (2014). Stercova et al. (2016) observed no significant differences in pH, Lactic acid bacteria and total coliforms of fresh faeces between the live yeast (LY) supplemented and control beagle dogs. However, faecal lactic acid contents showed a significant effect of treatment and sex interactions (P <0.10). The log cfu/g values of the S. cerevisiae were also significantly higher in faeces of the LY animals (P < 0.01).
On contrary, inclusion of LAB in diet of pre and post weaned foals increased faecal lactic acid. Sreekumar and Hosono (2000) reported that short-term administration of L. acidophilus in rats with and without E. coli resulted in significant inhibition of coliforms and anaerobes. Oso et al. (2013) showed lower coliform counts in caecal content of rabbits when compared with those fed the control diet. In addition, increasing inclusion of probiotics mixture levels in the diets linearly increased (p < 0.05) faecal Lactobacillus counts and decreased Escherichia coli counts in weaning pigs (Nguyen et al., 2019).
Thus, it can be concluded from the observations of present study that probiotics L. acidophilus and S. cerevisiae can be safely incorporated up to 109 CFU/g concentrate for every 50 kg body weight/day into the diet of elephants without affecting the faecal profile.