Evaluation of optimum dietary inclusion level of probiotics for potential benefits on intestinal histomorphometry, microbiota, and pH in Japanese Quails

Among the alternative options of antibiotics as growth promoters (AGP) to reduce the antimicrobial resistance, probiotics are the attractive alternative which needs to compare at different doses with AGP on the intestinal health of Japanese quail. For this, a total 75 Japanese quails were equally assigned to five treatment groups having three replicates in each group (n=5). In addition to basal diet (control), four other groups were supplemented by AGP and probiotics at the dose of 0.015 gm/bird, 0.03 gm/bird, and 0.045 gm/bird. The results revealed, 0.03 gm/bird probiotics group had significantly (p<0.05) lower mean on gizzard and intestine relative weights (gm/kg) of 23.68 and 35.61; and the relative length (cm/kg) of duodenum, jejunum and ileum were 51.06, 137.30 and 101.95, respectively. Additionally, the villus height (VH) of jejunum and ileum had significantly (p<0.01) higher mean in 0.03 gm/bird probiotics group of 599.25 and 417.25 µm, respectively. Although, there was a quadratic relationship in VH of jejunum (p<0.001) and ileum (p<0.01), CD (p<0.01) and VH:CD (p<0.05) of duodenum with the probiotics dose, but only VH of jejunum and ileum (p<0.001) showed a linear interaction. The enumeration of intestinal bacteria was lower in AGP group but did not differ significantly (p>0.05) with 0.03 gm/bird probiotics group in which the E. coli, Salmonella, Staphylococcus and TBC mean was 5.160 log10, 4.440 log10, 2.923 log10 and 6.972 log10 CFU/gm, respectively. However, the highest pH was recorded in ileum in each group without any significant differences. In a short of, probiotics are effective substitute to AGP and having the potential effects on intestinal health especially for 0.03 gm/bird.