Wheat bran as dietary tool to improve dairy production, oxidative status of lactating cows and food sustainability indexes

Wheat bran (WB), an inexpensive by-product widely available in southern Italy, is largely used as component of feed for ruminants, contributing to decrease the use of food suitable for human consumption, thus to improve the sustainability of livestock production. However, the potential benefits of WB, due to its content in polyphenolic compounds, mainly consisted of ferulic acid, in improving rumen conditions and the antioxidant balance of animals, and also providing animal products with functional properties, are not yet well known. Accordingly, this experiment was carried out for 100 days with 36 lactating Italian Simmental cows divided into 3 groups receiving one of 3 concentrates including WB at 0% (WB0), 10% (WB10) or 20% (WB20), formulated to be isoenergetic and isoproteic. During the trial, the group feed intake and the individual milk production were monitored, and cheesemaking of bulk milk were carried out. Statistical analyses were performed using MIXED (individual data) and GLM (cheese traits) procedures in SAS 9.2. Milk yield was similar among groups throughout the trial. Milk from WB20 group resulted slightly higher in casein and curd firmness (a2r). In cows fed WB, the higher intake of polyphenols, especially ferulic acid, was responsible of a higher blood content of polyphenols, which had an impact on reactive oxygen metabolites (ROMs), resulted significantly higher in WB0 cows (115 vs 106 and 1045 U. Carr in WB0, WB10 and WB20; p .05). WB20 cheeses showed, compared to WB0, a tendency to have greater total polyphenol content (4.21 vs 3.65 mg GAE/g, p .10), lower number of peroxides (1.04 vs 1.30 mEqO2/kg, p .05) and higher antioxidant capacity (1848 vs 1518 mmol FeSO4/g, p .10), with intermediate values in WB10. WB20 diet, due to WB low cost, reduced the feeding cost for cow and for kg of milk yield, in comparison with the WB0 diet. In addition, the WB20 group showed the best indexes heFCE (human edible feed conversion efficiency ¼milk/human edible feed) and NFP (net food production ¼human edible food/milk), expressed as crude protein or gross energy. In conclusion, the WB ingested by dairy cows, at a level of about 12% of total DM intake seems lead to several benefits, such as the improvement of oxidative status of cows, milk quality, shelf-life characteristics and nutraceutical properties of cheese, as well as it can contribute to reduce the feeding cost per unit of product and limit the human-animal competition for feeding sources.