Growth performance and carcass characteristics of lambs fed halophytes as a partial or whole replacement of berseem hay

Abstract

The aim of this study was to evaluate partial or whole substitution of berseem hay with Atriplex nummularia (AT) and/or Acacia saligna (AC) in the diet of Barki lambs. Thirty-six male lambs (body weight 26.5±1.1kg and age 13±1.1 months) were divided into four groups and fed: (1) the control diet (70% concentrate mixture and 30% berseem hay), (2) AT (AT15 diet) or (3) AC (AC15 diet) replaced 50% of berseem hay in the diet, or (4) AT and AC at a ratio of 1:1 to replace 100% of berseem hay (TC30 diet), respectively. Lamb growth performance, rumen fermentation, blood chemistry, carcass characteristics and intestine histological properties were investigated. Dry matter intake, daily weight gain and feed conversion were measured every two weeks (period) for 10 weeks. Interactions were observed (P<0.05) between period×diet for these measurements and period affected (P<0.05) daily weight gain and feed conversion. Lambs in the AT15 and AC15 groups had increased (P<0.05) dry matter intake (g/lamb/day), water consumption (L/lamb/day), daily weight gain (g/lamb/day) and feed conversion (feed intake/body weight gain) during the last 2, 6, 2 and 8–10 weeks, respectively. The treatments AT15, AC15 and TC30 had decreased concentrations (P<0.01) of ruminal volatile fatty acids, but did not affect ruminal ammonia-N concentrations. Lambs fed the experimental diets had lower (P<0.05) concentrations of blood cholesterol, low density lipoproteins and glucose and higher (P<0.05) concentrations of serum urea. The treatment AT15 had increased (P<0.05) gut fill, pelt and mesentery weights, whereas the treatment AC15 increased (P<0.05) spleen and lung weight as a percentage of carcass weight. In regards to the protein content of the 9–11th ribs, the treatment AT15 was similar to the control, but the AC15 and TC30 were lower (P<0.05) than the control. Lambs in the treatment groups showed a normal histology of ileum, sub-mucosa and Peyer's patches. It could be concluded that AT or AC can replace 50% of berseem in the diet of Barki lambs without compromising lamb growth performance.