E ﬀ ect of the inclusion of fresh lemon pulp in the diet of lactating ewes on the properties of milk and cheese

This study investigated the e ﬀ ects of fresh lemon pulp (FLP), as a natural antioxidant in the diet, on the intake of feed and the production of milk and cheese of Valle del Belice lactating ewes during the hot summer in Sicily. A total of 15 second-lambing ewes, kept individually in 3 × 3 m pens, were divided into 3 homogeneous groups fed with 3 diets in a 3 × 3 Latin square design, with 3 experimental phases of 21 days each. The diets were: mixed hay ad libitum plus 600 g/day of concentrate (FLP0); mixed hay ad libitum plus 400 g/day of concentrate and 1 kg/day of FLP (FLP1); and mixed hay ad libitum plus 200 g/day of concentrate and 2 kg/day of FLP (FLP2). Nine experimental Pecorino cheeses were manufactured with bulk milk collected at the end of each phase from each group. The ewes of each group showed the same dry matter (DM) intake (2 kg/day/head), but the FLP2 group received lower (P = 0.001) net energy for lactation (NE L ) than other groups (2.13, 2.36, and 2.31 Mcal/day per head for FLP2, FLP0, and FLP1, respectively). The FLP constituted 9% and 16% of the total DM intake in the FLP1 and FLP2 groups, respectively. In general, the daily milk yield was low, re ﬂ ecting the e ﬀ ect of the high environmental temperatures, and was lower (P = 0.001) in the FLP2 group than in the other groups (323, 355, and 369 g/day for FLP2, FLP1, and FLP0, respectively), probably due to the lower daily energy intake. Milk protein (P = 0.046) and casein (P = 0.033) percentages were higher in the FLP2 group than in the FLP1 group; the FLP-fed groups had higher levels of (P = 0.011) milk urea than the FLP0 group, due to a higher (P = 0.001) CP/NE L ratio in the ingested diet (96.4, 95.8, and 95.3 g/Mcal for FLP2, FLP1, and FLP0, respectively). The fatty acid composition of milk from FLP2-fed ewes was higher in vaccenic (10.6 vs. 7.96 mg/g fat; P = 0.031) and rumenic acids (6.21 vs. 5.30 mg/g fat; P = 0.048) than that in milk from FLP0 ewes. The characteristics of the cheeses were not in ﬂ uenced by the diet, with the exception of the total content of phenolic compounds (P = 0.011) and antioxidant activity (P = 0.051), both of which were higher in cheeses made with milk from FLP-fed ewes. on the utilisation of fresh citrus pulp in the diet of dairy sheep. Studies examined the e ﬀ ects of whole citrus fruits (Clementines) on lactating ewes and found analogous e ﬀ ects on ruminal parameters between whole citrus fruits and fresh citrus pulp (Piquer et al., 2009) and no negative e ﬀ ects on milk (Jaramillo et al., 2009; Piquer et al., 2011) and cheese production 2009). A dietary integration of 2 kg/day per head or ad libitum administration of fresh lemon pulp (FLP) reported for dairy ewes in Sicily, and their e ﬀ ects on milk yield and composition 2006; Todaro 2006) and cheese characteristics 2004; Todaro Scatassa, 2011) have been evaluated. These studies have seen no negative e ﬀ ects on milk production, instead highlighting increased milk yield in dairy ewes fed with FLP ad libitum al., 2006). The e ﬀ ects on cheese characteristics regarded mainly the ﬂ avour, attributed to the higher presence of limonene and β -pinene in Pecorino cheeses made with milk from FLP-fed ewes 2004), while some problems linked to acidi ﬁ cation of the curd were observed in the production of pasta ﬁ lata cheese made from raw milk, as in the Vastedda della valle del Belice Protected Designation of Origin cheese (Todaro and Scatassa, 2011).