Thermal and probiotic treatment effects on restaurant waste for incorporation into poultry diet

Background Restaurant waste (RW) can be considered as a valuable feedstuff for animal nutrition due to its high nutritional value and low price. The aim of this study was to determine nutritional value and the microbial load of the waste in order to incorporate it in the poultry feedstuff. To our knowledge the current study is the first attempt in the field of RW processing with Lactobacillus strains. Then the second goal of this experiment was to study the effect of RW processing with Lactobacillus on nutrient and chemical composition of RW. The four Lactobacillus strains applied in the study included Lactobacillus casei subsp-1608 ATCC 39392, Lactobacillus plantarum-1058 ATCC 8014, Lactobacillus acidophilus-1643 DSM 20079 and Lactobacillus reuteri-1655 DSM 20016. Results The experiments in the case of chemical composition showed that the mixed processing caused a significant improvement in nutritional value compared to the raw waste (P < 0.05). Among the strains, L. acidophilus had the highest mean amount of crude protein (CP), ether extract (EE), dry matter and gross energy (GE) with 21.40, 19.91, 41.02 and 4,872.61 kcal/kg, respectively, and the lowest amount of ash (3.67 %) compared with other strains. In the second phase of the experiment, the results obtained from comparing the average total count of bacteria and coliforms in five types of RW proved that the means of both bacteria and coliforms are within the standard range and can be applied as poultry feed. However, regarding the average total count of bacteria, barbecue waste with 9.85 × 104 CFU/g and chicken waste with 9.51 × 103 CFU/g were the most contaminated and the healthiest foods, respectively. In addition, barbecue waste with 1.28 × 102 CFU/g and fish waste with 1.08 × 102 CFU/g had the highest and lowest count of coliforms, respectively. Conclusion Nutritional value determination of RW samples showed that it is in the level that can be used in poultry diet. It was also presented that by adding Lactobacillus strains to the waste, the amount of GE, CP and EE increased and ash amount decreased. Therefore, its use in poultry diet is highly economic. In addition, this study showed that RW microbial load is in the level that can be applied as poultry feedstuff.