Pistachio skin as a novel feedstuff for lambs: effects on growth performance and meat quality

The present study aimed to investigate the effects of dietary pistachio skin, a by-product of the confectionary industry, on the growth performance and meat quality of lambs. Twenty-four male lambs were assigned to 2 dietary treatments and fed for 60 days with a concentrate-based diet or the same diet with 120 g/kg DM of pistachio skin inclusion as a partial replacement of maize and soybean meal. We evaluated growth performance, ruminal fermentation, and lipid metabolism. The hydrophilic antioxidant capacity, and fat-soluble vitamins were assessed on fresh meat, while colour stability and lipid and protein oxidation were measured over 7-days of refrigerated storage. Dietary treatment did not affect growth performance, carcass traits, and ruminal fermentation (P > 0.05). Pistachio skin enriched meat with health promoting fatty acids, including vaccenic and rumenic acids (P = 0.037 and 0.031; respectively). Feeding lambs with a diet containing pistachio skin increased also meat tocopherols, including γ-tocopherol (P < 0.001), and reduced the lipid oxidation during 7-days of refrigerated storage measured as production of thiobarbituric acid reactive substances (P = 0.004). Meat from lambs fed pistachio skin showed lesser values of a*, b*, and C* colour descriptors (P = 0.001, 0.009, and 0.003; respectively). The development of hydroperoxides, thiols, and carbonyls was not affected by dietary treatment (P > 0.05). Feeding lambs pistachio skin as a replacement for conventional feedstuffs may be useful for reducing the environmental impact of the meat supply chain. The inclusion of pistachio skin can be a profitable strategy for improving the fatty acid profile and lipid oxidative stability of lamb, without adverse effects on growth performance and ruminal fermentation.