Feeding accounts for approximately 70% of total costs in livestock production, underscoring the need for cost-effective and high-quality alternative feed sources. Almond hulls (AHs), a byproduct of the almond processing industry, represent a promising option due to their availability and potential nutritional value. Moreover, their inclusion in animal diets contributes to a reduction in environmental waste associated with their disposal. This study examined the effects of incorporating 4% sodium hydroxide (NaOH)-treated AHs into the diets of Assaf sheep (rams, ewes, and growing lambs) on feed utilization and animal performance. The experiment evaluated the chemical composition of AHs, nutrient digestibility, sexual behavior and semen quality in rams, milk composition in ewes, and the performance of growing lambs fed diets with increasing levels of inclusion of AHs. A total of 60 ewes and 21 rams were randomly assigned to one of three treatment groups, receiving diets containing 0%, 20%, or 40% AHs. NaOH treatment reduced the concentrations of organic matter and fiber fractions, while increasing the crude protein concentration of AHs (p < 0.01). Diets containing AHs did not affect nutrient digestibility (p > 0.05). Feeding a diet with 40% Na-OH-treated AHs significantly improved the daily weight gain (p = 0.002) of growing lambs up to 70 days after birth, and enhanced (p < 0.05) the libido, scrotal circumference, and semen quality of mature rams. In addition, ewes fed a diet containing 40% AHs showed (p < 0.05) improved fertility, prolificacy, and milk quality. NaOH-treated AHs are a cost-effective and sustainable feed ingredient that can improve reproductive performance and milk production, thereby increasing overall livestock productivity. The 40% inclusion level yielded the most favorable outcomes across all performance parameters evaluated in rams, ewes, and lambs.

The purpose of this study was to investigate the effects of treating olive (Olea europaea) leaves with sodium hydroxide (NaOH) or urea (both at 4% for 40 d) or supplementing with polyethylene glycol (PEG) at 100 mg/g DM on their nutrient composition, gas production, methane (CH₄) and carbon dioxide (CO₂) productions, and fermentation profile. The results showed that NaOH-treated leaves had the lowest organic matter and fiber fractions, while urea-treated olive leaves exhibited the highest crude protein content (p < 0.001). Asymptotic gas production was significantly higher (p = 0.015) in urea-treated olive leaves compared to NaOH-treated leaves. Methane production was highest (p < 0.05) in urea-treated leaves and lowest in NaOH-treated leaves. During incubation, urea-treated leaves produced the highest CO₂ per gram of degradable neutral detergent fiber (p = 0.015). Degradability parameters indicated that PEG supplementation led to the highest DM, neutral detergent fiber, and acid detergent fiber degradability (p < 0.05) compared to the untreated and NaOH-treated leaves. Urea-treated leaves produced the highest acetic acid (p = 0.016) compared to PEG-supplemented and NaOH-treated leaves, showing no significant difference from the control. Butyric acid levels were higher (p = 0.011) in NaOH-treated and PEG-supplemented leaves than in the control and urea-treated leaves. Metabolizable energy (ME) was significantly higher (p = 0.013) in urea-treated leaves than in untreated and NaOH-treated leaves, with the latter producing the lowest ME. PEG supplementation resulted in significantly higher microbial protein (MCP) production (p = 0.023) compared to NaOH-treated and untreated leaves, while the MCP level in the urea-treated group was comparable to all other treatments. In conclusion, PEG supplementation was the most effective treatment for olive leaves’ degradability and MCP, with urea treatment being the second option. From an environmental perspective, NaOH treatment was the most effective for reducing CH₄ and CO₂ productions during the fermentation of olive leaves.

This study investigated the effects of supplementing a commercial milk replacer with Boswellia serrata resin (BSR), a natural frankincense extract rich in boswellic acids that possess anti-inflammatory and antioxidant properties, on the growth performance, serum biochemical parameters, and meat quality of suckling lambs. Twenty-four Assaf lambs were randomly assigned to three groups (n = 8 per group): natural suckling (NS), milk replacer (MR), and MR supplemented with BSR (MR+BSR). The experimental period lasted 60 days, during which growth performance and blood indices were evaluated, followed by meat quality assessment at the end of the trial. Lambs reared artificially (MR and MR+BSR) showed greater growth performance than naturally suckled lambs, as evidenced by significantly higher final body weight (p = 0.003) and average daily gain (p = 0.002), while initial body weight did not differ among treatments (p = 0.881). Within the artificially reared groups, however, BSR supplementation did not further increase growth relative to milk replacer alone. Supplementation with BSR improved the health and metabolic profile of lambs, resulting in higher serum total protein (p < 0.001), albumin (p < 0.001), and globulin (p < 0.001) concentrations. Moreover, BSR supplementation reduced the increase in aspartate aminotransferase (p < 0.001) and alanine aminotransferase (p < 0.001) activities observed in the MR group. No significant differences were detected in meat proximate composition (p > 0.05). However, meat from the NS group was significantly harder (p = 0.002) and more cohesive (p = 0.003) than meat from lambs fed MR or MR+BSR. In addition, the MR+BSR group produced meat with a higher redness (a*) value (p = 0.041), indicating an improved color quality. In conclusion, supplementing milk replacers with BSR enhanced the physiological and biochemical health of suckling lambs and enhanced specific meat quality traits, suggesting its potential as a natural functional additive in artificial rearing systems.

This study evaluated the effects of replacing 25% of wheat straw with dried carob (Ceratonia siliqua) leaves and twigs, either untreated or treated with 5% sodium hydroxide (NaOH), on growth performance, nutrient digestibility, carcass traits, meat quality, blood metabolites, and rumen microbial populations in Assaf lambs. Twenty-four male lambs (2.5 months old; 29 ± 0.5 kg) were randomly assigned to three dietary treatments (n = 8): a control diet containing wheat straw as the sole roughage source, supplemented with a concentrate feed, a diet with 25% untreated carob leaves and twigs (UCL), and a diet with 25% NaOH-treated carob leaves and twigs (TCL). Following a 14-day adaptation period, lambs were fed the corresponding experimental diet for 14 weeks. Carob inclusion improved growth performance, with UCL lambs showing the highest average daily gain (214 g/d) compared with TCL (201 g/d) and control (160 g/d), resulting in improved feed conversion ratio (9.02 vs. 5.68 and 5.63, respectively) (p < 0.001). Blood urea nitrogen was reduced (p < 0.001) in UCL lambs (26.8 vs. 38.5 mg/dL in control), suggesting improved nitrogen retention. Digestibility responses differed between treatments (p < 0.001), as TCL increased dry matter digestibility to 72.6% compared with 65.4% (UCL) and 63.6% (control), indicating enhanced nutrient utilization following NaOH treatment. Both UCL and TCL increased (p < 0.001) carcass weights (up to 24.7 vs. 21.0 kg in control), while TCL achieved the highest dressing percentage (46.6% vs. 43.4%). Meat quality traits were generally unaffected in terms of color (lightness, redness, and yellowness) and water-holding capacity; however, shear force decreased from 33.6 N (control) to 30.0 N (TCL), indicating improved tenderness. Carob inclusion modified meat composition by increasing (p < 0.001) lipid content (12.0–12.2 vs. 9.6%) and improving fatty acid profile, with reduced saturated fatty acids (53.4–56.5 vs. 61.4%) and increased α-linolenic acid (2.04 vs. 1.58%), leading to a lower n-6/n-3 ratio (5.54–5.61 vs. 6.45). Rumen fermentation was also affected (p < 0.001), as carob diets increased total bacterial populations and reduced protozoal counts, suggesting shifts toward more efficient microbial activity. In conclusion, replacing 25% of wheat straw with carob leaves improved growth performance and feed efficiency, with untreated carob primarily enhancing nitrogen utilization and treated carob improving fiber digestibility and carcass yield. These findings support the use of carob by-products as a viable alternative feed resource, although responses depend on processing method and targeted production outcomes.

This study evaluates the effects of plant part (leaves vs. stems), harvest season (spring vs. autumn), and irrigation on the chemical composition, in vitro ruminal fermentation kinetics, and digestibility of three Mediterranean leguminous shrubs: Acacia fimbriata, Medicago arborea and Anthyllis barba-jovis. Samples were collected under field conditions, analysed for chemical composition, and assessed for in vitro ruminal fermentation, including incubations with and without polyethylene glycol (PEG) to assess the biological activity of phenolic compounds. Crude protein and fibre fractions did not differ significantly among species; ash was highest (p < 0.05) in Ac. fimbriata. In vitro fermentation kinetics were similar among species; however, the response to PEG was higher (p < 0.05) for Ac. fimbriata than for M. arborea and An. barba-jovis. In vitro digestibility was superior (p < 0.05) in M. arborea and An. barba-jovis. Leaves contained higher ash and protein contents and less fibre than stems, resulting in greater gas production, fermentation rate, and digestibility (p < 0.05). Spring-harvested fodder showed higher digestibility than autumn samples. Irrigation had negligible effects, except for a marginal numerical but nonsignificant (p = 0.05) greater extent of degradation observed in browse prior to irrigation. Overall, M. arborea showed a better nutritional quality, whereas Ac. fimbriata was the species with the lowest nutritive value. Forage quality was strongly influenced by plant part and harvest season, with leaves and fodder in spring showing superior potential as a feedstuff for ruminants.

This study examined the effects of replacing 25% (P25) or 50% (P50) of concentrate dry matter (DM) with sun-dried carob (Ceratonia siliqua L.) pods on growth performance, apparent nutrient digestibility, carcass traits, meat quality, serum biochemistry, and rumen microbiology in growing Assaf lambs. Twenty-four weaned male Assaf lambs (initial body weight [BW] 27.0 ± 0.5 kg; 2.5 months of age) were randomly assigned to three dietary treatments (n = 8 per group) in a completely randomized design and fed for 16 weeks. P50 achieved the highest ANCOVA-adjusted least squares mean final BW (53.0 kg) and average daily gain (ADG) (220.8 g/d), followed by P25 (51.1 kg; 203.3 g/d) and the control (46.2 kg; 160.2 g/d) (p < 0.001). Feed conversion ratio (FCR) improved from 8.99 in the control to 6.16 and 6.11 in P25 and P50, respectively, with no significant difference between the two carob-supplemented groups (p < 0.001). Apparent DM and organic matter (OM) digestibility increased with carob inclusion at both 3 and 6 months of age (p ≤ 0.0001). Cold carcass weight (CCW) was higher in carob-supplemented lambs (p < 0.001), whereas carcass muscle proportion did not differ among treatments (p = 0.688), and carcass fat proportion was higher in P25 than in the control (p = 0.039). Warner–Bratzler shear force declined progressively with carob inclusion (p < 0.001), indicating improved meat tenderness. Serum total protein was highest in P25, whereas blood urea nitrogen (BUN), low-density lipoprotein (LDL), and glutamate oxaloacetate transaminase (GOT) decreased with carob inclusion (p < 0.001). Rumen pH was highest in P25 (6.40), total bacterial and lactic acid bacteria (LAB) counts increased, and protozoa counts declined (p < 0.001). Because carob pods replaced concentrate, rather than being added to an isonitrogenous diet, the combined effects of pods per se, reduced crude protein supply, and altered energy density must all be considered when interpreting the results. These findings support carob pods as a practical, locally available partial substitute for concentrate feed in Assaf lamb production under Mediterranean and Near Eastern conditions.