Effects of feeding Atriplex halimus L. on growth performance and carcass characteristics of fattening Awassi lambs

• Atriplex halimus L. was fed to Awassi ram lambs at levels of 0, 75, and 150 g/kg.
• Growth performance and carcass characteristics was comparable among dietary treatments.
• Cost of production was reduced in lambs fed Atriplex halimus L. containing diets compared to the control diet.

A study was conducted to determine the effect of partial replacement of wheat straw by Atriplex halimus L. (ATR) on growth performance, nutrient intake, digestibility, carcass characteristics and meat quality of Awassi lambs fed finishing diet. Twenty seven Awassi ram lambs (initial body weight 14.9 ± 0.54 kg) were divided randomly into three dietary groups. Group one served as a control and received no ATR (CON), group two (ATR75) and three (ATR150) received diet containing 75 and 150 g/kg ATR, respectively. Lambs were housed individually in shaded pen (1.5 × 0.75 m), and fed ad libitum isonitrogenous diets. Nutrient intakes were determined daily throughout the experimental period, which lasted for 91 days. On day 56, of the fattening period, 6 lambs from each group were chosen at random and housed individually in metabolism crates to determine nutrient digestibilities and N balance. At the end of the study, all lambs were slaughtered to evaluate carcass characteristics and meat quality. Intakes of dry matter (DM), organic matter (OM), crude protein (CP), and neutral detergent fiber (NDF) were similar among treatment diets as well as water intake. Growth performance parameters did not differ among all treatment diets although lambs fed on the CON diet had greater (P < 0.05) intake of acid detergent fiber (ADF) compared to lambs fed on ATR diets. Feeding cost was reduced (P < 0.05) when wheat straws was replaced by ATR. Digestibility of DM, OM, CP, NDF and ADF was similar among treatment diets. Nitrogen balance and fecal N was greater (P < 0.05) in ATR150 diet followed by CON and ATR75 diets. Rumen fluid pH and carcass characteristics showed similar values among all dietary treatments. The longissimuss muscle leaner dimensions and fat measurements were comparable among all treatment groups. Also, carcasses from different dietary groups scored similar pH, cooking loss, water holding capacity, shear force and color coordinates. Results of this study demonstrated the possibility of including A. halimus L. up to 150 g/kg in fattening diets of Awassi lambs without any adverse effects on growth performance, carcass characteristics and meat quality; whereas it reduced the cost of feeding.