Agri-food waste (AFW) and by-products represent sources of phytochemicals, such as phenols and antioxidant compounds that can be used as functional ingredients in animal feed. In this study, a selection of AFW and by-products were collected and analysed for their nutrient composition. After chemical (with methanol) and physiological (in vitro digestion) extraction, total phenolic content and antioxidant capacity (AOC) were determined in AFW and by-product samples using Folin–Ciocalteu and 2,2′-azinobis(3-ethylbenzothiazoline 6-sulfonic acid)-ABTS methods, respectively. Sample digestibility was also assessed using a multi-step enzymatic technique. After chemical extraction, grape marc showed the highest total phenolic content (4480.5 ± 886.58 mg TAE/100g; p < .05). Fruit and vegetable waste (FVW), orange peel, strawberry, citrus pulp and Camelina sativa cake showed a total phenolic content ranging from 238.0 ± 4.24 to 1583.0 ± 154.35 mg TAE/100g. Grape marc also showed the highest AOC (15440.7 ± 2671.85 mg TE/100g). In all other samples, AOC ranged from 43.3 ± 3.17 to 1703.9 ± 391.07 mg TE/100g. After physiological extraction, total phenolic content values higher than 3000 mg TAE/100g were observed in FVW, grape marc and orange peel. Grape marc, C. sativa cake and orange peel had AOC values of over 5000 mg TE/100g. The digestibility of AFW and by-products ranged from 44.20 to 97.16%. The lowest digestibility value was observed in grape marc (44.2 ± 2.31%). In conclusion, the results obtained in this study indicate that AFW and by-products could be a source of bioaccessible phenols and antioxidant molecules as ingredients for monogastric compound feeds.

The microbiota is extremely important for the animal’s health, but, to date, knowledge on the intestinal microbiota of the rabbit is very limited. This study aimed to describe bacterial populations that inhabit the different gastrointestinal compartments of the rabbit: stomach, duodenum, jejunum, ileum, caecum, and colon. Samples of the luminal content from all compartments of 14 healthy New White Zealand rabbits were collected at slaughter and analyzed using next generation 16S rRNA Gene Sequencing. The findings uncovered considerable differences in the taxonomic levels among the regions of the digestive tract. Firmicutes were the most abundant phylum in all of the sections (45.9%), followed by Bacteroidetes in the large intestine (38.9%) and Euryarchaeota in the foregut (25.9%). Four clusters of bacterial populations were observed along the digestive system: (i) stomach, (ii) duodenum and jejunum, (iii) ileum, and (iv) large intestine. Caecum and colon showed the highest richness and diversity in bacterial species, while the highest variability was found in the upper digestive tract. Knowledge of the physiological microbiota of healthy rabbits could be important for preserving the health and welfare of the host as well as for finding strategies to manipulate the gut microbiota in order to also promote productive performance.

Food loss and waste have a negative environmental impact due to the water, land, energy and other natural resources used to produce the wasted food, along with post-consumption disposal costs. Reducing food waste will thus help improve sustainability and decrease the environmental impact of the food system. Using food waste for animal feed is of growing importance in terms of the policies targeted at tackling food waste but the current legal framework in the European Union (EU) strongly restricts the possibility of using food waste for this purpose. The aim of this work is to evaluate the feasibility of innovative measures for feed production in the EU and to identify the best strategies to implement them. First, a technical evaluation of a case study is presented, which is a process developed in the United States for urban food waste transformation into animal feed. Second, there is an analysis of the potential application of this process in the European Union within the current legal framework. The results reveal that the feed product derived from food waste is compliant with EU safety requirements and is nutritionally valuable. This work also suggests that the implementation of this kind of process in the European Union has great potential, provided that food surplus is recovered and treated before it turns into waste and that the different types of food surplus identified are used as feed for the right animal type in accordance with European legislation (i.e., livestock, aquarium fish, pets). On these terms, pet food can be the most concrete strategy for using food waste within the European context. In general, the implementation of feed-from-food measures to reduce food waste in Europe is already possible and does not need to wait for further policy interventions.

The Sustainable Development Goals are a set of global goals that provide a framework for shared action. These goals also include the reduction of food waste and the definition of sustainable solutions to achieve food security. In this context, the aim of the study was to describe all phases of a pilot earthworm rearing project started in September 2017 and concluded in December 2017, together with a risk analysis carried out in order to evaluate if earthworms can represent a safe and sustainable protein source for human consumption and/or animal nutrition. The conversion rate, that in this study is more appropriately identified as the “waste reduction efficiency,” was also calculated in order to define the extent to which earthworm rearing can contribute to the objective of reducing fruit and vegetable waste (FVW). The results showed that earthworms can bio-convert 3750 kg of FVW in three months producing 1050 kg of compost and 82 kg of fresh earthworms with minimal environmental impact showing good waste reduction efficiency. Moreover, the risk analysis conducted on earthworm rearing highlighted a microbiological hazard after the freeze-drying phase. The critical control point was therefore identified, and, in order to guarantee the total food safety of the finished product, corrective action was taken consisting in the implementation of heat treatment—sterilization at 121 °C for 20 min. The results of microbiological analyses carried out on the earthworm meal after the sterilization treatment showed that the treatment guarantees microbiological safety for the consumer and ensures a balanced approach in relation to two main topics—public health and food-borne diseases. In conclusion, earthworm meal is a concentrate of valuable nutrients useful for human and animal nutrition and can also transform fruit and vegetable waste into a resource.