Enhancement of lamb meat quality: Effects of dietary supplementation of pistachio hulls

Pistachio hulls were evaluated as a nutrient source in the Sarda lamb finishing system in this study. Twenty male lambs (initial body weight 32.2 ± SD 0.42 kg) were fed for 40 days with either a concentrate diet (169 g/kg dry matter of crude protein, control group) or the same concentrate diet of the control group in which 20% (on a dry matter basis) of the cereals were replaced with pistachio hulls (HP20 group). Hay (Sulla, Hedysarum coronarium) was given ad libitum in a separate feeder. The results showed that no alterations in growth performance of lambs occurred following feeding with pistachio hulls; however, the feed conversion ratio (FCR) of lambs was slightly higher in the PH20 group than in the other dietary treatments (P = 0.049). Intramuscular fat content in lambs fed the PH20 diet was greater (P = 0.032) than in the control lambs. Lambs fed the PH20 diet had greater amounts of stearic acid (P = 0.036), rumenic acid (P = 0.005), and α-linolenic acid (C18:3 n-3; P = 0.049) in their longissimus thoracis et lumborum muscle (LTL). During 7 days of aerobic storage at 4 °C, thiobarbituric acid reactive substances (TBARS) increased in both groups (P < 0.001); however, concentrations of TBARS were significantly lower (P < 0.001) in PH20 meat compared to control meat. Lastly, the croma (C*) of lambs fed the PH20 diet were significantly greater than those fed the control diet (P = 0.014), indicating improved colour stability of PH20 meat compared to control meat. Overall, replacing 20% of dietary dry matter with pistachio hulls preserved animal performance while improving selected nutritional and oxidative stability traits of lamb meat.