Effects of inclusion of waste vinegar residue in the diet of laying hens on chyme characteristics and gut microflora

The objective of this study was to evaluate the effects of inclusion of waste vinegar residue (WVR) in the diet of laying hens on chyme characteristics and gut microflora. A total of 96 60-wk-old Hy-Line Brown laying hens were selected and fed three diets including a corn and soybean meal-based control diet and two other diets with 20 g/kg and 40 g/kg of WVR. After 27 d feeding period, digesta was collected for protease activity, pH value and microflora determination. Bacterial genetic diversity was determined using DGGE analysis of the V3 region of 16S rDNA PCR products (230 bp) obtained from primers specific for the domain Bacteria. Inclusion of 20 g/kg and 40 g/kg of WVR in the diet decreased the digesta pH value in the gizzard (P=0.003) and increased pepsin activities in the gizzard of laying hens (P=0.032). Species of Enterobacter and Peptostreptococcaceae were more predominant in the cecum and ileum of laying hens, respectively. It is concluded that inclusion of 40 g/kg of WVR in the laying hen diet modifies intestinal pH value and pepsin activities in upper gastrointestinal tract and affects the lower gut microflora in laying hens.