Production, oxidation traits and health of dairy ewes fed diets supplemented with fungus myceliated grains.

Abstract

Mushrooms contain many bioactive compounds, mainly poly- and oligosaccharides, known to have benefits for human health. Polysaccharides from mushrooms exhibited immunomodulatory, antibacterial, antiviral, and antifungal properties, as well as antitumor activity. Furthermore, some mushrooms showed to have potent antioxidant properties due to the presence of phenolic acids, flavonoids, polysaccharides, carotenoids, ascorbic acid, and tocopherols. These beneficial properties of mushrooms bioactive compounds indicate their potential use as performance-enhancing natural feed additives for livestock animals. In this regard, the use of mushrooms and mushroom-derived products has largely been investigated in the feeding of poultry species, showing positive effects on immune system, microbial and parasite control in the intestines, antioxidant protection, and overall animal health and production. Until now, however, few studies have reported the effects of mushroom-based diets on the health status and productive responses of ruminant livestock animals. Accordingly, a study was undertaken to evaluate the effects of diets supplemented with fungus myceliated grains (FMG) fed to dairy ewes on intestinal parasite control, milk production and fatty acid (FA) profile, and cheese oxidative stability. During an 8-week period, 21 Valle del Belice ewes were divided into 3 homogeneous groups which were fed with hay ad libitum and 1.3 kg/day per ewe of one of 3 isoproteic and isofibrous concentrates containing faba bean (50%), barley (30%) and sorghum grains (20%), these latter included as FMG or non-myceliated grains; accordingly, the FMG were supplied at levels of 20% (FMG20), 10% (FMG10) or 0% (FMG0). FMG were prepared by incubating sterile sorghum grains with mycelia of selected mushrooms at 25°C for 8 weeks, then they were dried at 60°C for 24 h and stored at 4°C until used. The ewes fed FMG20 diet showed comparable dry matter (DM) and nutrients intake, a reduction in intestinal parasite infection, a tendency towards increased milk yield, and a higher milk casein content (4.8% vs 4.3% and 4.3% in FMG20, FMG10 and FMG0; P<0.05) than the ewes of FMG10 and FMG0 groups. The FMG was responsible of production of cheeses with higher lightness and redness, and less intense yellow colour. Cheeses made with FMG20 milk showed a lower secondary lipid oxidation, as indicated by the trend of TBARs values, and a higher antioxidant capacity, as detected by the TEAC assay (17.8 vs 10.0 and 9.2 mmol trolox eq/kg DM, in FMG20, FMG10 and FMG0; P<0.001), suggesting a major oxidative stability of cheese fat due to a probable presence of antioxidant compounds induced by FMG. The FMG in the diet did not affect the content of health-promoting polyunsaturated FA in milk, with the exception of n-3 eicosapentaenoic acid (EPA), found only in milk from FMG-treated ewes. Based on these results, FMG showed to have antiparasitic and antioxidant effects and, at a level of 20% in the concentrate, corresponding to 7.4% in the diet, they lead to increased milk yield and improved general health of the ewes. Also, FMG enhanced the properties of dairy products by enriching the cheeses with antioxidant compounds and increasing, as a consequence, the oxidative stability of cheese fat. These encouraging results require to be confirmed by further investigations into the potential use of mushrooms or FMG as natural feed additives for enhancing the health and production of ruminant livestock animals, and especially to study the ability of mushroom by-products to confer health properties to dairy products and make them functional food.