Agro-industrial by-products as a feeding strategy for producing functional milk

Agro-industrial by-products contain valuable components such as polyphenols that can play a significant role in producing milk with specific properties through rumen fermentation. In Egypt, the buffalo milk chain has a potential market, which is larger than that for cow milk, especially in small villages. Therefore, this study aims to explore different feed ingredients from agro-waste for enhancing the functional properties of raw buffalo milk including polyphenols, flavonoids, vitamins A, C, α-tocopherol, and conjugated linoleic acid (CLA) contents. For this purpose, thirty dairy water buffalo (Bubalus bubalis) with a weight of about 520 kg were randomly divided into five groups of six animals each. The first group was fed a basal diet (silage) without agro-waste, while the other four groups were fed the basal diet after replacing 25% of the diet with different agro-wastes including barley (snack/bakery waste), sweet potato/carrot, biscuit/cake waste and tomato pomace. The feeding experimental period lasted 90 days, then milk samples (n = 150) were collected. Our results show that adding sweet potato/ carrot or tomato pomace to the basal diet enhanced the contents of vitamins A, C, and phenolic compounds reflecting on the enhancement of the antioxidant capacity of raw buffalo milk. Concerning the CLA content, the milk samples collected from buffalo fed the basal diet fortified with tomato pomace and biscuit/cake waste had the highest CLA and α-tocopherol content. Therefore, this study recommends using the tested agro-waste ingredients for producing functional buffalo milk, especially for small-medium milk producers.