Dietary supplement guava leaf extract regulates growth, feed utilization, immune function, nutrient digestibility and redox regulation in growing rabbits.

The use of agricultural waste in animal production has gained global interest. An eight-week trial was conducted to investigate the impacts of adding ethanolic guava leaf extract (GLE) as a feed supplement on the growth, feed utilization, immune response, nutrient digestibility, redox regulation, and blood health of growing rabbits. Ninety weaned growing rabbits were randomly assigned to three groups. The first group was fed a basal diet (GLE0), while the other two groups were fed the control diet fortified with 15 mg (GLE15) or 20 mg (GLE20) of GLE per kg of diet for 8 weeks. The HPLC analysis of GLE exhibited the presence of gallic acid, ferulic acid, catechin, and caffeic acid in significant amounts. The results indicated that final body weight, daily body weight, daily feed intake and nutrient digestibility were significantly higher in the GLE-treated groups compared to the un-treated group (p < 0.05). Dietary supplementation of GLE significantly reduced lipid contents including triglycerides, total cholesterol, LDL, HDL, and VLDL (P < 0.05), with the most significant results observed when adding 20 mg/kg to the diet. AST and ALT levels as well as cortisol hormone in rabbits fed GLE were lower than those in the GLE0 group (P < 0.05). Immunoglobulins (IgG and IgA), antioxidant biomarkers (SOD and TAC) and T3 hormone were significantly improved by GLE supplementation (P < 0.001). Rabbits fed with GLE had lower levels of ROS and MDA compared to those in the GLE0 group (P < 0.001). Moreover, the hepatic and intestinal architectures were maintained in all rabbits fed diets with GLE. The results suggest that GLE supplementation (20 mg/kg diet) in fattening rabbit diets could efficiently improve growth, health status, blood physiology, antioxidant capacity and tissue histology.

Dietary Supplementation of Microalgae and/or Nanominerals Mitigate the Negative Effects of Heat Stress in Growing Rabbits.

Heat stress (HS) is one of the most significant environmental factors that result in fluctuations and shrinkage in rabbit growth, health, and overall productivity. This study aims to investigate the effects of dietary mineral nanoparticles (selenium or zinc) and/or Spirulina platensis (SP) independently and in combination on stressed growing rabbits. A total of 180 weaned growing New Zealand White rabbits were included in this study and randomly divided into six dietary treatments. Rabbits received a basal diet (control group; CON group) or fortified with SP (1 g/kg diet), selenium nanoparticles (SeNPs, 50 mg/kg diet), zinc nanoparticles (ZnNPs, 100 mg/kg diet), and a mixture of SP and SeNPs (SPSeNPs) or SP and ZnNPs (SPZnNPs) groups for 8 weeks during summer conditions. The obtained results demonstrated a significant increase in the final body weight and weight gain (p < 0.05). Additionally, the feed conversion ratio was improved during the periods from 6 to 14 weeks in the treated rabbits compared to those in the CON group. Dietary supplements considerably improved (p < 0.05) the blood hematology (WBCs, Hb, RBCs, and Hct) and some carcass traits (liver weights and edible giblets). All dietary supplements significantly decreased serum levels of total glycerides (p < 0.0001), AST (p = 0.0113), ALT (p = 0.0013), creatinine (p = 0.0009), and uric acid (p = 0.0035) compared to the CON group. All treated groups (except ZnNPs) had lower values of total bilirubin and indirect bilirubin in a dose-dependent way when compared to the CON group. The values of IgA, IgG, and superoxide dismutase were significantly improved (p < 0.05) in all treated rabbits compared to the CON group. Compared with the CON group, the levels of T3 (p < 0.05) were significantly increased in all treated growing rabbits (except for the ZnNP group), while the serum cortisol, interferon-gamma (IFN-γ), malondialdehyde, and protein carbonyl were significantly decreased in the treated groups (p < 0.05). Dietary supplements sustained the changes in hepatic, renal, and cardiac impairments induced by HS in growing rabbits. Adding SP (1 g/kg diet) or SeNPs (50 mg/kg diet) in the diet, either individually or in combination, improved growth performance, blood picture, and immunity-antioxidant responses in stressed rabbits. Overall, these feed additives (SP, SeNPs, or their mixture) can be applied as an effective nutritional tool to reduce negative impacts of summer stress conditions, thereby maintaining the health status and improving the heat tolerance in growing rabbits.

Effect of addition of l-carnitine to cryopreservation extender on rabbit post-thaw semen parameters, antioxidant capacity, mitochondrial function, apoptosis and ultrastructure changes.

l-Carnitine (LC) is considered to be a natural antioxidant agent that could be used to improve the efficiency of reproduction. However, the precise machinery of the effect of LC supplementation on frozen-thawed rabbit sperm has not been evaluated. Thus, the aim of this study was to evaluate the effect of the addition of LC to a freezing medium on parameters and ultrastructure changes in frozen-thawed rabbit sperm. Rabbit bucks (7 months of age) were involved, and semen was collected using the artificial vagina method. Pooled rabbit semen was cryopreserved in a tris yolk fructose extender without any supplement (LC0, control group) or with LC at levels of 1, 2 or 4 mM (LC1, LC2 and LC4, respectively). The samples were then loaded into 0.25-ml straws and frozen over liquid nitrogen vapours before being plunged into the liquid nitrogen and stored at -196°C until evaluation. Data showed that the addition of LC significantly increased sperm motility, viability and membrane function, while sperm abnormalities decreased (p < .001). Sperm-like apoptosis (early, late and necrosis spermatozoa) was lower in the LC4 group compared with the other groups. l-Carnitine addition significantly enhanced the total antioxidant capacity and superoxide dismutase and glutathione peroxide activities and significantly reduced the protein carbonyl and malondialdehyde levels compared with the control group. Moreover, electron microscopy images demonstrated that LC addition (2 or 4 mM) preserved the acrosome and plasma membrane and protected the ultrastructure integrity of the cryopreserved spermatozoa in relation to the control group. Spermatozoa treated with LC exhibited higher mitochondria membrane potential (MMP) values compared with the control group. We conclude that the addition of LC (4 mM) to the freezing extender enhanced the quality, increased the antioxidant capabilities, preserved the ultrastructure integrity and reduced lipid and protein peroxidation as well as increased MMP activity of frozen-thawed rabbit sperm.

Effects of Dietary Biological or Chemical-Synthesized Nano-Selenium Supplementation on Growing Rabbits Exposed to Thermal Stress.

The adverse influences of elevated ambient temperatures during the summer season on the rabbit industry have received increased global attention. Therefore, this study intended to compare the potential effects of nano-selenium (nano-Se) synthesized by biological (BIO) and chemical (CH) methods on growth performance, carcass variables, serum metabolites, and inflammatory cytokines responses of growing rabbits in the summer season. Two hundred and fifty weaned rabbits (males, 35 days of age) were randomly divided into five treatment groups of 50 rabbits each (each group had five replicates with ten male rabbits). Treatment groups were fed a control diet and four controlled diets supplemented with nano-Se synthesized by biological method (BIO25 and BIO50, with a 25 and 50 mg of nano-Se/kg diet, respectively) and chemical method (CH25 and CH50, with a 25 and 50 mg of nano-Se/kg diet, respectively) for eight weeks. During 11 to 13 weeks of age, a gradual enhancement in live body weight (LBW), feed intake (FI) and feed conversion ratio (FCR) was noticed with BIO25 and BIO50 treatments compared to those in the other groups. The carcass percentage was significantly higher (p < 0.01) for animals fed with BIO25 than the other groups. The other organ functions were significantly higher (p < 0.01) in heat-stressed groups compared to that of nano-Se groups. Increasing the level of only BIO from a 25 to a 50 mg/kg diet gave more improvement in the studied parameters. Additionally, the concentrations of serum urea, triglycerides (TG), and glutamyl transferase (GGT) were lower (p < 0.01) in both treated and untreated groups. Likewise, the supplementation with nano-Se (BIO25, BIO50, or CH25) significantly improved the antioxidant indices and inflammatory cytokines responses as indicated from serum metabolites. Based on the study results, nano-Se especially synthesized by the biological method at diet levels of 25 or 50 mg/kg improved the growth performance, kidney and liver functions, carcass traits, antioxidants indices, and inflammatory cytokines of growing rabbits during thermal stress.

Relationship between concentrations of macro and trace elements in serum and follicular, oviductal, and uterine fluids of the dromedary camel (Camelus dromedarius).

This study aimed at investigating the relationship between concentrations of macro and trace elements in blood serum, and fluids from small and large follicles (SFF and LFF, respectively), oviduct (OF), and uterus (UF) of female dromedary camels. Fluids from small (2-6 mm) and large follicles (7-20 mm), oviduct and uterus, and blood samples were collected from 19 camels. The results indicated that the concentrations of serum Mg, Fe, and Mn were significantly higher than their follicular fluid, OF, and UF concentrations. Levels of Zn, Fe, Cu, Cr, and Mn were significantly higher in SFF than in LFF. Se and Mo concentrations were higher in LFF. Co concentration was lower in serum than in reproductive tract fluids. Cr concentration was higher in UF and OF than in the serum, SFF, and LFF. High Ca concentration was observed for serum and SFF, followed by LFF. The concentration of Na was about 1.18-fold higher in SFF than in serum, OF, and LFF, and approximately 4.1-fold higher in serum than in UF. K was present in higher concentration in SFF than in serum and LFF; however, its concentration was low in UF and OF. In conclusion, this study shows the concentrations of certain elements in small and large follicular, uterine, and oviductal fluids, which may be low or high depending on their function in the development and growth of follicles. This information can support the development of new media for in vitro oocyte maturation and fertilization of female camels.

Impacts of Enriching Growing Rabbit Diets with Chlorella vulgaris Microalgae on Growth, Blood Variables, Carcass Traits, Immunological and Antioxidant Indices.

This work aimed to explore the effects of dietary supplementation of Chlorella vulgaris (CLV) on the growth performance, carcass traits, hematobiochemical variables, immunity responses, and the antioxidant status of growing rabbits. A total number of 100 rabbits were randomly distributed into four treatment groups, each of five replicates (25 rabbits/group). The experimental groups were as follows; control: a basal diet without supplementation, CLV0.5: basal diet + 0.5 g chlorella powder/kg diet; CLV1.0: basal diet + 1.0 g chlorella powder/kg diet, CLV1.5: basal diet + 1.5 g chlorella powder/kg diet. Live body weight (LBW), cumulative body weight gain (CBWG), feed intake (FI), and feed conversion ratio (FCR) were not affected by dietary CLV supplementation. Platelet count (PLT), hematocrit (HCT), means corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) values were significantly increased in the CLV0.5 group compared with the other treatment groups. Dietary supplementation of CLV (1.5 g/kg diet) significantly reduced the alanine aminotransferase (ALT) activity. The concentrations of serum triglycerides and very low-density lipoprotein (VLDL) were lower (p < 0.05) in the CLV-treated groups than those of the control. Supplemental CLV at all experimental levels gave the best values of immunoglobulins (IgG and IgM) and glutathione activities. Malondialdehyde (MDA) levels were lower in the animals that received CLV in their diet than those of the control group. Dietary supplementation of 1.0 g CLV/kg had the potential to enhance immune responses and antioxidant status, as well as reduce blood lipid accumulation. Therefore, it could be concluded that CLV supplementation to growing rabbit diets can improve the health status.

Growth, Carcass Traits, Blood Hematology, Serum Metabolites, Immunity, and Oxidative Indices of Growing Rabbits Fed Diets Supplemented with Red or Black Pepper Oils.

The present study aimed to examine the impacts of the supplementation of red or black pepper oils to rabbit diet as growth promoters on New Zealand white (NZW) rabbits. One hundred and forty weaned NZW rabbits were divided randomly into seven groups in a completely randomized experiment using different quantities of red pepper oil (RPO; 0.5, 1.0, 1.5 g/kg diet) or black pepper oil (BPO; 0.5, 1.0, 1.5 g/kg diet), in addition to the control group. Compared to the control, values of live body weight (LBW) for rabbits fed either RPO or BPO enriched diets were greater. The concentrations of serum triglycerides and cholesterol were lower (p < 0.01) in the RPO- and BPO-treated groups than in the control. Immunity parameters and antioxidant indices were improved in treated groups in comparison to the control. Dietary RPO or BPO can affect some growth traits, improve immunity parameters and the antioxidant activity, and decrease the lipid profile and lipid peroxidation. The use of 0.5 g RPO/kg diet as a dietary supplement had a larger effect on growth parameters than the other treatment groups.