Enhancing the nutritional value of date palm leaves via solid-state fermentation and its impact with single-cell protein on lambs' performance.

The study looked at how solid-state fermentation affects date palm leaves (DPL) and how it influences lamb performance, both with and without single-cell protein. DPL was fermented using three different strains of microbes. Using the Cornell Net Carbohydrates and Protein System, the nutritional value of DPL treatments, including fermented date palm leaves (FDPL) and DPL supplemented with single-cell protein designated as high protein (HP), was assessed under the study for chemical composition. To assess FDPL, eighteen crossbred male lambs, with an average live weight of 25 ± 0.2 kg, were divided into two groups. Whereas the second group got 40% concentrate feed mix (CFM), 50% FDPL, and 10% HP, the first group was fed a meal comprising 40% CFM and 60% FDPL. Compared with unfermented DPL, FDPL increased crude protein by 60% and reduced crude fiber by 28.7%. The calculated total digestible nutrients (TDN) value increased from 38.7 to 46.8% (+ 21.0%). Supplementing FDPL with HP further increased crude protein from 8.0 to 15.8% (+ 97.5%) and increased TDN from 46.8 to 66.7% (+ 42.5%). In the feeding trial, HP supplementation increased crude protein, TDN, and metabolizable energy intake, improved nutrient digestibility, feed conversion ratio, and feed efficiency, increased final body weight and average daily gain. Serum total protein, globulin, urea, and glucose increased, whereas AST and ALT remained within the normal physiological range. Overall, solid-state fermentation improved the feeding value of DPL, and the addition of a protein-rich single-cell protein product to FDPL further enhanced lamb performance without evidence of adverse health effects.