Probiotics intake from proximal or distal gastrointestinal tract: The investigation on intestinal morphology and performance of Japanese quail.

The aim of the present study was to investigate the efficacy of early single-dose probiotics administered from proximal or distal gastrointestinal tract on quails' performance and small intestinal morphology. A total of 120 Japanese quail (Coturnix coturnix japonica) 1-d-old chicks were divided into the following experimental groups before being transferred to the raising room: (i) control (no probiotic administered); (ii) oral group (received probiotics via oesophageal gavage); and (iii) vent lip group (received probiotics directly into vent). Four replicates of 10 chicks per cage were considered for each treatment and birds were raised up to 35 days in the same conditions with ad libitum access to feed and water. A commercial probiotics (Protexin, Somerset, UK) used in this study contained 2 × 109  cfu/g of nine different micro-organisms. On day 35, all birds were weighed and then three birds in every pen were killed via cervical dislocation. Two cm of mid-point of duodenum and ileum were cut for histomorphology assays. Both probiotics-treated groups had higher body weight and body weight gain than control (p < .01). Ileum was longer in probiotics-treated groups than in the control (p < .01). Orally treated birds had the highest duodenum villus height and crypt depth (p < .01). In the cloacally treated quails, ileum villus length was higher than the both other groups, and crypts' depth was deeper than the control (p < .01). The numbers of both types of goblet cells (acidic mucin producer and neutral mucin producer) were higher in the birds receiving probiotics than control birds (p < .01). Although there were no statistical differences in performance values between the different ways of probiotics entrance into gut, some intestinal histomorphometric parameters were improved in ileum of the birds receiving probiotics through distal gut that is cloaca (p < .01).