Influence of Trichoderma reesei or Saccharomyces cerevisiae on performance, ruminal fermentation, carcass characteristics and blood biochemistry of lambs fed Atriplex nummularia and Acacia saligna mixture

• Lambs of the AF consumed more feed by 13% than AS lambs.
• Lambs fed AF and AS increased volatile fatty acid production versus Controls.
• Lambs fed AS had the highest dressing percentage.
• A normal histology of the ileum, sub mucosa and peyer's patches.

The aim of this study was to evaluate whole substitution of Egyptian berseem hay (Trifolium alexandrinum) with a mixture of Atriplex nummularia and Acacia saligna (1:1 DM) in the diet of Barki lambs for 70 days. Thirty six lambs (27.0±0.89 kg initial BW) were divided into four treatment groups of nine lambs each and fed: (1) the Control group with no substitution (70% concentrate mixture and 30% berseem hay, DM basis), (2) A. nummularia and A. saligna mixture without fungal treatment (treatment group AU), or (3) Trichoderma reesei treated A. nummularia and A. saligna mixture (treatment group AF), or (4) A. nummularia and A. saligna mixture supplemented with Saccharomyces cerevisiae at 0.5 g/kg DM of feed (treatment group AS) replaced 100% of berseem hay in the diet. Live-weight change, rumen fermentation parameters, blood chemistry, carcass characteristics and intestinal histology were investigated. Significant (P<0.05) interactions occurred between diet and period for feed conversion efficiency and blood serum urea. Lambs in the AS treatment consumed less (P<0.05) feed than lambs in the AF treatment, with no difference between the other treatments (P>0.05). Lambs fed AF and AU diets had lower (P<0.05) feed conversion efficiency than lambs fed the AS and Control diets. Lambs fed AF and AS had increased (P<0.05) volatile fatty acid production compared to Controls. Blood albumin and urea concentrations increased (P<0.05) with lambs in AS treatment compared to lambs in the other treatments, while lambs fed AF had lower (P<0.05) cholesterol and glucose concentrations compared to the Controls. The AS lambs had the highest (P<0.05) dressing percentage. Decreased intramuscular fat weights were obtained with lambs fed halophytes compared to Control lambs. Histology of the ileum, sub mucosa and Peyer's patches were normal in all lambs. In conclusion, untreated halophyte mixtures of A. nummularia and A. saligna (at 1:1 DM) can be substituted for berseem hay without negative effects on performance while treatment with S. cerevisiae may improve performance and, like T. reesei, change certain biochemical responses.