Can bakery and confectionery products be used in pig feed?

The study*, which was conducted in Italy, set out to determine if food industry leftovers (or former food products) could offer a valid alternative to grains in young pigs’ nutrition. The research team investigated the possibility of partially replacing standard ingredients with two different types of former food products (namely, bakery or confectionery former food products) and studied their effects on growth performance, feed digestibility and metabolic status in post-weaning piglets.

High digestibility of former food products as pig feed

A recent analysis of former food products considered these products in terms of their nutritional and functional properties, chemical composition and digestibility. It defined them as a “fortified version of common cereals” because of their higher metabolizable energy (about 14 MJ/kg), fat and starch content on dry matter basis, compared with traditional feedstuffs.

It is widely known that piglets benefit from the consumption of easily digestible carbohydrates until their digestive system is fully able to handle starch. Studies on carbohydrate digestibility have shown that, compared with common cereals, former food products have a higher digestibility potential due to the presence of readily available simple sugars and processed starch, which is probably also related to the industrial processes they undergo, such as heat and mechanical treatments.

The study of former food products given to piglets

In the study 36 post-weaning female piglets were randomly assigned to three experimental diets for 42 days. These were:

• A standard diet or the control group.

• A diet in which 30% of the standard ingredients were replaced by confectionery former food products (e.g. chocolates, biscuits and sweet snacks).

• A diet in which 30% of the standard ingredients were replaced by bakery former food products (e.g. bread, pasta and savoury snacks).

One initial concern in using former food products in pig diets could be the difficulty of formulating a standard feed due to the variability of the ingredients used for the FFP production. However, based on the results of the study, this might not be a factor.

Results in terms of bodyweight and growth performance

All the animals remained in good health throughout the experiment and there were no morbidity or mortality issues, and no effect between experimental groups was observed for all the growth performance parameters. Accordingly, the results of the present study regarding pigs’ growth performance showed that there were no significant differences in bodyweight between the groups. Bodyweight measured at the piglets’ arrival and at the end of the trial did not differ between diets. Average daily feed intake was not affected by any dietary treatments. In addition, the experimental diets did not influence the average daily gain and feed conversion ratio. Furthermore, no significant effects of the diets were found in the analysed hematological parameters between groups over the entire experiment.

This study, therefore, showed that the 30% inclusion of 2 different types of former food products rich in fat and carbohydrates in the diets of post-weaning piglets is possible. It was demonstrated that bodyweight, average daily feed intake, average daily gain and feed conversion rate were similar between the three groups. Former food products – both bakery and confectionery – could offer a good option for replacing a significant amount of conventional cereals in pig feed and therefore be included in post-weaning pig diets as alternative ingredients to improve sustainability in the livestock sector.

*This study was conducted by Alice Luciano, Marco Tretola, Sharon Mazzoleni, Nicoletta Rovere, Francesca Fumagalli, Luca Ferrari, Matteo Ottoboni and Luciano Pinotti from the University of Milan in Italy, and Marcello Comi from the Università Telematica San Raffaele in Rome, Italy. Marco Tretola also represents Agroscope, the Institute for Livestock Sciences in Switzerland.