This study aimed to evaluate the nutrient digestibility of growing rabbits fed diets with different levels of either Leucaena leucocephala (LLM) or Moringa oleifera (MOLM) leaf meals and also to compare total collection and TiO2 marker methods for estimating digestibility. A total of 30 California growing rabbits (1.81±0.19 kg live weight on average) were randomly distributed into five experimental groups of six rabbits each and were housed in individual cages. The groups were control, 30% LLM, 40% LLM, 30% MOLM, and 40% MOLM. All groups received pelleted diets for two weeks; diets also contained 4 g/kg titanium dioxide as dietary marker. Daily feed intake was recorded during the whole experimental period and total feces were collected daily and weighed individually during four days. The results showed that there were no difference (p>0.05) in feed, dry matter (DM), organic matter (OM), crude protein (CP), digestible energy, and crude fiber (CF) intake between the control group and the other experimental groups. The apparent digestibility values of DM, OM, CP, CF, acid detergent fiber, and gross energy were the highest for control group (p = 0.001), meanwhile MOLM diets had generally higher nutrient digestibility coefficients than LLM diets. Increasing the inclusion level of leaf meal in the diet from 30% to 40% improved the digestibility of CF from 45.02% to 51.69% for LLM and from 48.11% to 55.89% for MOLM. Similar results for apparent nutrient digestibility coefficients were obtained when either total collection or indigestible marker method was used. In conclusion, the digestibility of MOLM containing diets were better than LLM diets, furthermore TiO2 as an external marker could be used as a simple, practical and reliable method to estimate nutrients digestibility in rabbit diets.

Two methods of feed preference trials were compared to evaluate the acceptability of 5 fresh foliages: Leucaena leucocephala, Moringa oleifera, Portulaca oleracea, Guazuma ulmifolia, and Brosimum alicastrum that was included as control. The evaluation included chemical analyses and forage intake by rabbits. The first method was a cafeteria trial; 12 California growing rabbits aged 8 wk, allocated in individual cages, were offered the five forage plants at the same time inside the cage, while in the second trial 60 California growing rabbits aged 8 wk, allocated individually, were randomly distributed into 5 experimental groups (n = 12/group); for each group just one forage species was offered at a time. The testing period for each method lasted for 7 d, preceded by one week of adaptation. The results showed that B. alicastrum and L. lecocephala were the most preferred forages while on the contrary G. ulmifolia was the least preferred one by rabbits. The results also revealed that the CV% value for the 2nd method (16.32%), which the tested forages were presented separately to rabbits, was lower and methodologically more acceptable than such value for the 1(st) method (34.28%), which all forages were presented together at the same time. It can be concluded that a range of tropical forages were consumed in acceptable quantities by rabbits, suggesting that diets based on such forages with a concentrate supplement could be used successfully for rabbit production. However, growth performance studies are still needed before recommendations could be made on appropriate ration formulations for commercial use.

This review discusses the findings of existing research surrounding the nutritional impact of some forages as well as leaf and seed meals that were incorporated in rabbit diets, furthermore the importance of dietary fiber to improve the digestive health for growing rabbits. Optimum growth performance can be achieved by feeding forages or leaf meals with concentrates in the rabbit diets. Tropical plants contain appreciable amount of protein, fat, minerals and carbohydrates that can support growth and production, however much of these plants contain also anti-nutritional factors which have negative effects on digestion or absorption of nutrients. The review revealed that different forages inclusion levels enhance rabbit production and can help overcome the protein intake deficiency in developing countries. Therefore, the utilization of forage plants as well as tropical grasses and legumes for rabbit feeding is recommended.

The present study aimed to examine the impacts of supplementing hot red pepper oil (HRPO) to broiler diets. One hundred and twenty Arbor Acres chicks were divided randomly into four experimental groups as three supplementation levels of HRPO (0.25, 0.5 and 1.0 mL/kg diet) and the control group. Results showed that HRPO supplementation exhibited significantly (p < 0.001) higher red blood cells (RBCs) count, hemoglobin (Hb) and packed cells volume (PCV) percentage, while insignificant effects were shown for white blood cells (WBCs) count or its differentiation. Diets supplemented with different levels of HRPO influenced significantly (p < 0.001) the total protein (TP), albumin (Alb) and glucose (Glo) values of the studied birds. Results also indicated that different levels of HRPO supplementations significantly (p < 0.01) decreased total lipid, triglycerides (Trig), cholesterol (Cho) and low-density lipoprotein (LDL), but did not affect high density lipoprotein (HDL) values. Data revealed that supplementing broiler diets with different levels of HRPO enhanced their liver function. The bactericidal activity index was significantly increased (p < 0.02) compared with control. HRPO supplemented groups had beneficial effects (p < 0.02) on cecal microbiota count. It could be concluded that dietary HRPO supplementation could improve the general internal health status of Arbor Acres broiler chicks.

The effect of including lemongrass extract powder (LGEP) as a phytogenic herbal extract supplementation for growing rabbits on productive performance, nutrient digestibility, blood parameters and carcase characteristics were evaluated. One hundred twenty unsexed V-Line rabbits, with 35 days age and 802 ± 47 g weight, were used. Rabbits were divided equally into four treatments to be fed on basal diet as a control diet without lemongrass inclusion (LGEP0) or with the inclusion of LGEP at 2 g (LGEP2), 4 g (LGEP4) or 6 g (LGEP6) per kg diet. Feeding LGEP did not significantly affect final body weight, weekly weight gains, feed consumption or feed conversion ratio. Moreover, no significant effect of supplementing rabbit diets with LGEP was observed on all apparent nutrient digestibility. The LGEP4 treatment decreased (P<.05) blood malondialdehyde, while LGEP contained treatments increased blood immunoglobulin G concentration as well as spleen relative weight (P<.01) compared to the control treatment. Although LGEP inclusion levels did not significantly affect productive performance traits, the studied LGEP treatments may help to enhance the anti-oxidative status and relative immune response of growing rabbits.