Growth performance, plasma metabolites, meat quality, and meat and lipid health indices of New Zealand White rabbits as affected by dietary dried tomato pomace powder supplementation during the summer season.

One hundred and twenty New Zealand White rabbits (NZW) (5-week-old; 735.27 ± 27.23 g) were kept in an open-sided house during the summer season. The experiment aims to evaluate the impacts of dried tomato pomace powder (DTPP) supplementation on rabbits' performance, blood metabolites, carcass traits, meat quality, and lipid and health indices of NZW rabbits during 5-13 weeks of age. The four treatments were a standard rabbit feed (control) and the control diet supplemented with 0.5, 1.0, and 1.5% DTPP, respectively. Rabbits fed a diet containing 1.5% DTPP showed the highest growth rate through weeks 9-13 of age despite having the lowest feed intake spanning 5-13 weeks. The best feed conversion ratio (FCR) was recorded in rabbits fed with 1.5% DTPP-supplemented diet for 5-13 weeks. Diets supplemented with 0.5 or 1.0% DTPP enhanced markedly dressing %, total edible flesh, saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated fatty acid (PUFAs) contents, as well as the ∑n - 6/∑n - 3 ratio and the total n - 6 of meat. Dietary supplementation with DTPP decreased kidney, abdominal, and back fat. Diets supplemented with DTTP decreased total cholesterol, triglycerides, and very low-density lipoprotein (vLDL) concentrations. The greatest levels of linoleic acid, arachidonic and water-holding capacity in meat were observed in rabbits fed 1.5% DTPP-supplemented diets. Diets containing 1 and 1.5% DTPP improved meats' atherogenic and thrombogenic indices, meat lipid quality desired fatty acids/undesired fatty acids ratio, and meat health index. Conclusively, DTPP up to 1.5% maintained the growth performance of rabbits, boosted meat quality through increasing vitamin E, reduced fat deposition, modified fatty acid composition, and improved atherogenic, thrombogenic, and hypocholesterolemic indices of rabbit meat.

Productive performance, lipid profile and caecum microbial counts of growing rabbits treated with humic acid.

The aim of the present study was to evaluate the effect of a humic acid (HA)-supplemented diet on productive performance and some physiological parameters of growing rabbits. A total of 80 weaned V-line rabbits at an age of 4 weeks were randomly divided into four groups. Rabbits of groups 2, 3 and 4 were fed diet containing 35 (HA35), 70 (HA70) and 105 (HA105) mg Humic acid/kg diet while the first group served as control (HA0). Body weight gain was positively affected by HA treatment. HA105 rabbits had the improved feed conversion value. HA treatments had significantly reduced plasma cholesterol concentration and significant increased red blood cells, white blood cells count and plasma high-density lipoprotein concentrations. However, serum aspartate amino transferase and alanine amino transferase activities, creatinine and the apparent nutrients digestibility values were not affected by HA treatments. Organic matter digestibility of all HA-treated groups significantly increased compared with HA0. At 63 days of age (after 35 days of treatment), caecum microbial counts decreased (total bacteria and Escherichia coli) with HA treatments. Generally HA could be considered as a biological as growth promoter feed additive alternative to antibiotics.

Effect of dietary pomegranate by-product extract supplementation on growth performance, digestibility, and antioxidant status of growing rabbit.

The study objective was to investigate the effect of three levels of dietary pomegranate by-product extract (PBE) (100, 150, and 200 mg) on growth performance, nutrient digestibility, carcass characteristics, and some blood parameters. Sixty weaned New Zealand White (NZW) rabbits at 5 weeks of age with an average body weight 561.67 ± 6.68 g were randomly allotted to four dietary groups; each group included three replicates (five rabbits each). The control group was fed a basal diet without PBE; the other three experimental groups fed diets supplemented with PBE at 100-, 150-, and 200-mg/kg diet. The results revealed that dietary supplementation of PBE at each level significantly (P < 0.05) improved the average final body weight and FCR. Rabbits group fed diet supplemented with 200 PBE recorded the highest (P < 0.05) of all nutrients digestibility, DCP, TDN, and DE. Feeding rabbits on diets supplemented with PBE at levels 100-, 150-, and 200-mg/kg diet increased (P < 0.05) plasma concentrations total protein, albumin, globulin, HDL, TAC, SOD, and GSH-Px, compared to the control group. The opposite trend was noticed with glucose, total lipids, triglycerides, total cholesterol, and LDL concentrations whereas they were lower (P < 0.05) than those of the control group. The obtained results also showed that PBE supplementation levels reduced (P < 0.05) both E. coli and salmonella counts in rabbit cecum. It could be concluded that the supplementation of rabbit diets with PBE at 100-, 150-, and 200-mg/kg diet improved growth performance and the nutrient digestibility. Moreover, PBE had an antioxidant and antibacterial effect of the growing rabbits.

Effects of dietary levels of brown seaweeds and plant polyphenols on growth and meat quality parameters in growing rabbit.

Growth performances, carcass characteristics and meat quality parameters from growing rabbit fed with two levels of dietary brown seaweed (Laminaria spp) and plant polyphenols were investigated. One hundred and forty-four New Zealand White rabbits were allotted into three dietary treatments containing 0 (C), 0.3% (T1), and 0.6% (T2) of brown seaweed and plant polyphenols mixture for 42 days. Growth performances and carcass weight were improved in T1 group. Vitamin A and E content in Longissimus thoracis and lumborum (LTL) and Semimembranosus (SM) muscle were enhanced in the treated groups. In the SM muscle, the oxidative stability was improved in rabbit fed with both dosages of dietary supplement, and the cholesterol content tended to be lower in T1 than in T2 and C groups. The LTL and SM muscle sensory characteristics were improved. In conclusion, dietary integration with a low dosage of brown seaweed and plant polyphenols is a valid strategy for enhance growth performance and produce healthier rabbit meat.

Dietary supplementation of potassium sorbate, hydrated sodium calcium almuniosilicate and methionine enhances growth, antioxidant status and immunity in growing rabbits exposed to aflatoxin B1 in the diet.

The present experiment was conducted to evaluate the effect of dietary supplementation with some feed additives (potassium sorbate; Sor, hydrated sodium calcium almuniosilicate; Hsc and L-methionine; L-M) against aflatoxin B1 (AF) toxicity in rabbits. A total of 72 growing rabbits (5-week-old) were distributed into six equal groups (4 replicates with 3 rabbits each). The experimental groups are as follows: control group, AF group (supplemented with AF 0.3 mg/kg diet), AF + Sor group (AF 0.3 mg/kg diet + Sor 2 g/kg diet), AF + Hsc group (AF 0.3 mg/kg diet + Hsc 5 g/kg diet), AF + L-M group (AF 0.3 mg/kg diet + L-M 8 g/kg diet) and AF + Mix group (AF 0.3 mg/kg diet + 2 Sor + 5 Hsc + 8 L-M g/kg diet). Live body weight and weight gain at 13 weeks of age were significantly reduced by AF. Feed intake at 13 weeks of age was decreased in AF, AF + Hsc and AF + Mix compared to the control. AF, AF + Hsc and AF + Mix showed the lowest total antioxidant capacity compared to the control. The highest level of reactive oxygen species and 8-Hydroxy-2-desoxyguanosine was observed in AF group. Using of other supplements with AF increased immunoglobulinM than AF alone. In conclusion, dietary supplementation of Sor, L-M, Hsc or their mixture was effective in reducing the adverse effects of AF on performance, antioxidant and immune status of rabbits with more better improvement obtained by Sor or L-M separately.

Influence of multi-enzyme preparation supplemented with sodium butyrate on growth performance blood profiles and economic benefit of growing rabbits.

The present study was carried out to explore the impacts of dietary supplementation of enzyme mixture with sodium butyrate on the growth performance, carcass traits, blood profile and economic benefit in two breeds of weanling rabbits adapted to survive in Egypt (New Zealand White and Rex). One-hundred and twenty weaned male rabbits (New Zealand White and Rex) of 6 weeks of age and 770.5 ± 20 g body weight were allotted randomly into four groups in a factorial arrangement. The obtained results indicated that there were non-significant differences in all growth performance traits, blood profile and economic parameters due to the breed effect. However, there were significant differences in most of carcass traits due to the breed effect except total giblets and New Zealand White breed showed the highest value of these parameters including dressing % (p < .01), forequarter and loin % (p < .001) and hindquarter % (p < .003) compared with Rex breed counterparts. The effect of the treatment and its interaction with the breed significantly (p < .05) improved body weight gain, feed consumption and carcass traits (percentage of dressing, forequarter, hind quarter and lion). However, final body weight and feed conversion ratio were not significantly influenced. Supplementing a diet with treatment significantly decreased blood triglycerides, cholesterol and the ratio between albumin and globulin (A/G ratio), while increased blood total protein and globulin. Although higher feed cost and total costs in treated groups than control ones in each breed, they showed higher total return and net return. Rex non-treated rabbit breed showed the lowest profitability measures compared with other groups. In conclusion, dietary supplementation of multi-enzyme with sodium butyrate is highly recommended in growing rabbits due to their beneficial effects on the growth performance and profitability.

Effect of bee pollen on growth performance, carcass traits, blood parameters, and the levels of metabolic hormones in New Zealand White and Rex rabbits.

The aim was to evaluate the effect of bee pollen (BP) on performance, blood parameters, and metabolic hormones in New Zealand White (NZW) and Rex (RX) rabbits. A total of 60 six-week-old rabbits were allotted into a completely randomized design in a 2 × 3 factorial arrangement (two breeds and three levels of BP: 0, 250, and 350 mg/kg body weight). The effects of breed × BP supplementation level were non-significant for all growth performance and carcass traits, as well as the concentrations of metabolic hormones in the plasma. Meanwhile, some blood parameters (hemoglobin, packed cell volume, alanine aminotransferase, aspartate aminotransferase, and urea) were significantly affected (P < 0.05). Regardless of the effect of breed, the supplementation of BP at a dose of 350 mg/kg BW increased the final body weight (P = 0.008), average daily gain (P < 0.001), and net profits (P = 0.006). However, the rabbits treated with BP at a dose of 250 mg/kg BW showed lower average daily feed intake (- 14.45 g/d; P = 0.049) and feed to gain ratio (- 0.48; P = 0.039). In both rabbit breeds, BP at a dose of 350 mg/kg increased the concentrations of insulin-like growth factor-1 (302.62 ng/ml, P < 0.001), insulin (16.63 ng/ml, P = 0.050), and triiodothyronine (158.50 ng/dl, P < 0.001) in plasma compared with other groups. It may be concluded that intake of BP supplementation can improve the feed to gain ratios, blood indices, and metabolic hormones in different rabbit breeds. However, the appropriate dosage and the route of supplementation of BP in broiler rabbits need further research.

Dietary supplementation of chestnut and quebracho tannins mix: Effect on caecal microbial communities and live performance of growing rabbits.

The interest in antimicrobial compounds as feed additives is currently increasing. Among different options, tannins seem to have several beneficial effects when employed in animals diet. The present study aimed at investigating the influence on caecal microbial communities of the supplementation of a chestnut and quebracho tannins mix in meat rabbit's diet, also considering animals live performances. Four groups of rabbits were fed with a different diet: a control diet (C); a control diet with coccidiostat (CC), and two experimental diets with 0.3% (T0.3) and 0.6% (T0.6) chestnut and quebracho tannins mix. For microbial analysis, culture-dependent and culture-independent methods were employed. Live performances were not significantly affected by tannins mix supplementations, as well as culturable microbial loads of E. coli, Enterobacteriaceae, Bacteroides spp. and Bifidobacterium spp. C. perfringens was always under the detection limit. A consistent result was obtained by qPCR. As for PCR-DGGE analysis, the Richness and evenness (Shannon-Weiner index) of bacterial communities in caecum resulted significantly higher in control samples (C and CC) than in those from rabbit fed with tannin-containing diets. Sequencing analysis revealed that the phylum Firmicutes was less represented in samples from control groups. As for the methanogen archaeal DGGE, no significant differences were found in richness and diversity among different groups, all dominated by Methanobrevibacter spp.. This work highlights the potential antimicrobial effect of chestnut and quebracho tannins mix in an in vivo system revealed by molecular analysis.

Lantibiotic Nisin Applied in Broiler Rabbits and Its Effect on the Growth Performance and Carcass Quality.

Nisin is a bacteriocin marketed as Nisaplin. The aim of this study was to follow the effect of commercial lantibiotic nisin on the growth performance and carcass quality of broiler rabbits. The increase of average daily gain (by 9.4%) was recorded in the nisin group. The treatment did not have a negative influence on the pH, colour, water-holding capacity, protein and fat contents or energetic value of the rabbit carcass. Inferring from the higher average daily gain and the higher protein and lower fat content, we conclude that the diet supplementation with nisin may enhance the quality of rabbit meat.

Evaluation of the carryover effect of antibiotic, bee pollen and propolis on growth performance, carcass traits and splenic and hepatic histology of growing rabbits.

Sixty-four nulliparous female rabbits were distributed among eight groups (eight animals/group). Group one was the unsupplemented control group; the other seven groups were supplemented with zinc bacitracin (ZnB) at 100 mg, or bee pollen (BP) and/or propolis (Pro) at 150 and 300 mg in a capsulated form, three times a week, day after day, continuously all over the experimental period. The experiment was run for eight parties; at each parity, 28 kids of each doe group (a total of 224 rabbits) were divided into two subgroups weaned, respectively, at 24 and 30 days of age. Thus, for each parity, there were 16 groups (eight does treatments × two weaning age, 14 rabbits per group). The growing rabbits fed the standard diets without supplements. The growth performance, the carcass traits, the liver and the spleen histology of rabbits were checked up to 90 days of age to find possible carryover effects of the supplements. The supplements had no significant effect on most of the growth performance at 90 days of age, but BP150 and BP+Pro300 increased the growth rate in comparison with ZnB group. The liver weight in the control, BP300 and Pro300 groups was higher than the ZnB one. The spleen weight was higher in the groups ZnB, BP150, Pro300 and BP+Pro300, followed by the control, BP300 and BP+Pro150 and thus Pro150. The heart % in the BP150 and Pro300 groups was higher than ZnB and BP+Pro150 groups. A lymphoid hyperplasia of splenic white pulp was observed in the BP+Pro groups, while propolis alone showed a mild activation of lymphobiosis. The Pro and BP groups showed the same picture of the control group exhibiting a hydropic degeneration of mostly hepatic cells, while the ZnB group exhibited adverse effect on the bile ducts featuring portal periductal inflammatory cells infiltration with epithelial hyperplasia reflecting chronic cholangitis.

Dietary addition of Artemisia argyi reduces diarrhea and modulates the gut immune function without affecting growth performances of rabbits after weaning1.

The present study was conducted to investigate the effect of Artemisia argyi on the production performance and intestinal barrier of rabbits. Weaned Hyla rabbits (30 d, n = 160) of similar body weight were divided into 4 groups (40 rabbits per treatment), and they were fed a control diet or fed an experimental diet supplemented with 3%, 6%, or 9% A. argyi. The results showed that the dietary supplementation with A. argyi did not affect the rabbits' food intake and body weight gain regardless of the inclusion level but decreased the diarrhea rate and diarrhea index (P < 0.05). Dietary addition of A. argyi increased the small intestine length and villus height/crypt depth, regardless of the inclusion level (P < 0.05). Compared with the control, the A. argyi supplementation increased the gene expression of zonula occludens 1 (ZO-1) and claudin 1 in all segments of the small intestine and regardless of the level of A. argyi (P < 0.05). In the duodenum, a dietary supplementation with 6% and 9% A. argyi increased the immunoglobulins A (IgA) content (P < 0.05). In the jejunum, the A. argyi supplementation decreased interleukin 2 (IL2) and IL6 content regardless of the inclusion level (P < 0.05). In the ileum, a 3% A. argyi addition decreased IL2 content, whereas a 6% A. argyi addition decreased IL6 content (P < 0.05). Furthermore, 6%-9% A. argyi supplementation increased the IgA content in the ileum (P < 0.05). In conclusion, dietary addition of A. argyi reduces diarrhea and modulates the gut immune function without affecting growth performances of rabbits.

The effects of dietary tomato powder (Solanum lycopersicum L.) supplementation on the haematological, immunological, serum biochemical and antioxidant parameters of growing rabbits.

Using nutritional antioxidants in livestock systems is considered the key in improving animal production. The current study assumes that dietary tomato powder (TP) supplementation positively affects haemato-immunological, biochemical, and antioxidant parameters for New Zealand rabbits. A total of 30 rabbits (45 days old) were assigned to three groups, including a diet with no additives (control), and two dietary treatments with the providing of 1% or 2% TP. Mass spectrometric study for TP methanolic extract showed some phenolic compounds. Consumption of TP supplemented diets significantly (p < 0.001) affected body weight gain and feed efficiency. Red blood cells and white blood cells count exhibited a significant increase (p < 0.001) in both TP groups compared with the control. In addition to, feeding rabbits on TP enhanced cell-mediated and humoral immune responses through a significant increase in phagocytosis, chemotaxis, and levels of immunoglobulins (TIg, IgG, IgM and IgA). Supplementation of TP significantly (p < 0.01) reduced lipid profile induces except high-density lipoprotein cholesterol values. A remarkable significant (p < 0.001) effect on serum and hepatic oxidative stress responses were observed with TP addition. Ultimately, TP supplementation could play a potential role as a growth and health enhancer for fattening rabbits.

Plant extracts and essential oil product as feed additives to control rabbit meat microbial quality.

The present work evaluated the effects of feed supplementation with plant extracts (onion, cranberry) and a commercial essential oil product (Xtract™) on rabbit meat quality. Five groups of 48 weaned Grimaud female rabbits each received a control ration (C) or a diet supplemented with onion extract (500 or 1000 ppm), cranberry extracts (500 ppm) and essential oil product (100 ppm) alone or in combination. Microbiological quality was evaluated on whole hind legs stored under aerobic and anaerobic conditions at 4 °C. Growth performances, feed intake and both meat composition and quality were similar amongst the experimental groups. Anyhow, meat total phenolic content was significantly higher in all supplemented ones (P < 0.001). Diet supplementation effect was observed (P < 0.05) and microbial control was improved more importantly under anaerobic conditions, notably for Total Aerobic Mesophilic counts, presumptive Pseudomonas and Enterobacteriaceae (P < 0.03). Overall, supplementation with onion extract (500 ppm) suppressed microbial growth more effectively.

Responses of growing rabbits to supplementing diet with a mixture of black and red pepper oils as a natural growth promoter.

The current study was explored to examine the impacts of dietary inclusion of mixture of black (BPO) and red pepper (RPO) oils as growth promoters on growth, carcass, blood haematology, serum chemistry, immunity and antioxidative status of New Zealand White rabbits (NZW). A number total of 100 5-week-old NZW growing weaned rabbits were randomly allocated into four treatment groups in a complete randomized experiment. The dietary treatment groups were as follows: control: basal diet; BRP0.5: basal diet + 0.25 g BPO + 0.25 g RPO/kg diet; BRP1.0: basal diet + 0.50 g BPO + 0.50 g RPO/kg diet; and BRP1.5: basal diet + 0.75 g BPO + 0.75 g RPO/kg diet. Rabbits fed the highest level of BRP mixture were the heaviest, while the control rabbits were the lightest. During 5-9 weeks of age, a gradual improvement in feed conversion ratio (FCR) was noticed with increasing BRP level. The control group excelled all BRP groups regarding the majority of blood haematological parameters. Liver function was better in rabbits fed BRP enriched diets than the control. A gradual depression (p < 0.05 or 0.01) in serum lipids regardless high-density lipoprotein (HDL) were recorded with elevating BRP level in the diet. The supplementation of BRP mixture enhanced the immune function and serum superoxide dismutase (SOD) activities and depressed serum malondialdehyde (MDA) in comparison with control. It could be concluded that dietary BRP mixture can affect some of growth traits, improve the immunity and antioxidant parameters, lower lipid profile and lipid peroxidation. Based on the study results, the recommended level of BRP mixture is 1.5 g/kg diet.

Effect of dietary supplementation of recombinant Cry and Cp4 epsps proteins on haematological indices of growing rabbits.

Genetically modified (GM) crops expressing insect resistance and herbicide tolerance provide a novel approach for improved crop production but their advent at the same time presents serious challenges in terms of food safety. Although prevailing scientific proof has suggested that transgenic crops are analogous to their conventional counterparts, their use in human and animal diet gave rise to emotional public discussion. A number of studies had been conducted to evaluate the potential unintended effects of transgenic crops expressing single transgene, but very few studies for those with multiple transgenes. As the crops with single and multiple transgenes could impart different effects on non-target organisms, thus, risk evaluation of transgenic crops expressing more than one transgene is required to declare their biosafety. The present study was therefore designed to assess the effects of different levels of dietary transgenic cottonseed expressing recombinants proteins produced by Cry1Ac, Cry2A and Cp4epsps genes on haematological indices of growing rabbits. A total of 48 rabbits were assigned to four dietary treatments containing different levels of transgenic cottonseeds (i.e., 0% w/w, 20% w/w, 30% w/w and 40% w/w) with 0% w/w serving as control. Haematological parameters were measured at periodic intervals (0, 45, 90, 135 and 180) days. No significant (p > 0.05) dose-dependent effects were observed in most of the haematological parameters evaluated. Though, significant differences (p < 0.05) were recorded in the level of MCHC, MCH and HCT in some of experimental male and female rabbits, yet, they were not biologically significant, as all the differences were within the normal reference values. Our study suggested that feeding transgenic cottonseed of up to 40% could not adversely affect rabbit's haematological profile. However, further study needs to be conducted with different cotton genotypes expressing both single and polygenic traits before recommending the utilization of transgenic cottonseed in routine livestock feeding.

Probiotic Clostridium butyricum Improves the Growth Performance, Immune Function, and Gut Microbiota of Weaning Rex Rabbits.

Probiotics could promote animal growth and enhance immune function. This study investigated the effects of Clostridium butyricum (CB) on the growth performance, intestinal immune, and gut microbiota of weaning rex rabbits. A total of 60 healthy female rabbits (5-month-old) were divided equally into four groups and mated on the same day: control group (CTRL, fed with basal feed), low-dose group (LDG, fed with basal feed + 1.0 × 103 CFU/g CB), middle-dose group (MDG, fed with basal feed + 1.0 × 104 CFU/g CB), and high-dose group (HDG, fed with basal feed + 1.0 × 105 CFU/g CB). Then, 30 weaning rex rabbits (35-day-old) were collected from each group for this experiment, and they were offered the same feeds as their mother. The results demonstrated that high-dose CB treatment significantly increased average daily weight gain of weaning rex rabbits. Further studies suggested that CB enhanced small intestinal digestive enzyme activity and improved mucosal morphology and antioxidant status. Supplemented with CB, small intestinal barrier function was maintained with the upregulation of mRNA levels of ZO-1, claudin, and occludin as well as the increase of sIgA production. Moreover, the relative expressions of MyD88, TLR2, and TLR4 were elevated in HDG; simultaneously, pro-inflammatory cytokines including IL-6, INF-γ, and TNF-α were decreased after CB administration. In addition, CB showed beneficial effects in improving weaning rex rabbit intestinal microflora via increasing the abundance of beneficial bacteria. Therefore, our results indicated CB can promote rex rabbit growth, which is likely to the enhancement of immune function and the improvement of intestinal microbiota.

Rabbit metabolic response and selected meat quality traits: Evaluation of dietary PLX® 23 and LycoBeads® feed supplement.

Effects of dietary supplementation of verbascoside and lycopene, alone and in combination, on some blood parameters, plasma oxidative status and meat quality traits in intensively reared rabbits were investigated. The test lasted 60 days and was conducted on 200 weaned-rabbits, divided into four groups of 50 animals each (5 animals each cage × 10 repetitions). The control group (CON) received a fattening feed without any feed supplements, whereas the experimental groups received the following: the first, an integration in 22 g of PLX® 23 (Lippia citriodora extract; VB group) per ton of feed; the second, an integration in 100 g of LycoBeads® (Solanum lycopersicum extract; LIC group) per ton of feed; and the third, an integration of both feed supplements in combination at the same doses (LIC+VB group). The dietary supplementation with Lippia citriodora and Solanum lycopersicum resulted in an improvement of the blood lipid profile, oxidative plasma markers, and hepatic and renal activity of treated growing rabbits. Feed additives also produced meat with a lower content in SFA and an increased PUFA content, and inhibited the lipid oxidation improving the oxidative stability of rabbit meat. The dietary supplementation, even reporting no effects on productive parameters and carcass yield, showed an improvement on several blood parameters, as indicator of animal welfare, and on quality and healthy meat markers.

Influence of Moringa oleifera extract, vitamin C, and sodium bicarbonate on heat stress-induced HSP70 expression and cellular immune response in rabbits.

The current study aimed to test the effect of Moringa oleifera extract (MOE), vitamin (Vit) C, and sodium bicarbonate (NaHCO3) on heat stress (HS)-induced alterations in rabbits. Five groups of rabbits were designed as control, HS, HS + MOE, HS + Vit C, and HS + NaHCO3. HS groups were exposed to high temperatures, while treatments were given in drinking water for 6 weeks. Levels of blood cortisol, leptin, IFN-γ, TNF-α, and IL-10 were assayed using ELISA, while adrenaline was assayed calorimetrically. Expression of HSP70, FOXP3, T cell receptor (TCR) γ, and δ mRNA was tested using real-time (RT)-PCR, while HSP70 protein expression was tested using western blotting in liver and kidney tissues. Infiltration of regulatory T cells (Treg; CD25+) and NK (CD56+) cells were tested using immunohistochemistry (IHC). The levels of liver enzymes (ALT & AST), urea, and creatinine were assayed calorimetrically, while body weight gain (BWG) and feed conversion ratio (FCR) were calculated. The results showed increased levels of cortisol, adrenaline, leptin, IFN-γ, TNF-α, ALT, AST, urea, and creatinine but decreased IL-10 in the HS group. Increased expression of HSP70 on both mRNA and protein levels was associated with increased NK and γδ T cells versus decreased Treg cell infiltration in liver and kidney tissues of the HS group. In the same group, BWG was decreased, while FCR was increased with respect to the control group. All treatments used in this study reversed the effects of HS significantly. In conclusion, MOE, Vit C, and NaHCO3 can be added to rabbit diets for the amelioration of HS-induced symptoms.

The effect of cellobiose on the health status of growing rabbits depends on the dietary level of soluble fiber.

The aim of this study was to examine whether the combination of dietary soluble fiber and cellobiose exerts a synergistic effect on growth performance, health status, fermentation traits, and immune response in rabbits. Six treatments in a 3 × 2 factorial arrangement were used: 3 cellobiose concentrations in drinking water (0.0, 7.5, and 15.0 g/L) × 2 dietary levels of soluble fiber (84.0 and 130 g/kg DM, for the low soluble fiber [LSF] and high soluble fiber [HSF] diets, respectively). A total of 318 young rabbits (53/treatment) were weaned at 34 d of age and had ad libitum access to feed and water. At 46 d of age, 9 rabbits/treatment were slaughtered and ileal and cecal digesta were collected to analyze VFA profile and the immune response in the cecal appendix mucosa. At 48 d of age, the cellobiose supplementation was withdrawn and the experimental diets were replaced by a standard commercial diet until 61 d of age. From 34 to 48 d of age, there was a linear increase of mortality with the level of cellobiose in the HSF group (0% vs. 17.1%; P = 0.017). In contrast, a quadratic effect of cellobiose level on mortality was observed in the LSF group, the rabbits offered 7.5-cellobiose showing the lowest mortality (5.7% vs. 21.4%; P = 0.030). Cellobiose level had a quadratic effect on ADFI, ADG, and G:F in this period (P ≤ 0.047), with the 7.5-cellobiose groups having the best growth performance. In contrast, only minor changes on these traits were observed from 48 d of age onwards. Cellobiose level influenced quadratically the ileal VFA concentrations (P = 0.014), showing the maximal value in the 7.5-cellobiose groups. In rabbits fed 7.5-cellobiose-LSF, a change of acetate to propionate, butyrate, and valerate was observed in the ileum. Increasing cellobiose levels reduced linearly cecal VFA concentrations in HSF fed rabbits, but no effect was detected in LSF groups (P = 0.046). The level of soluble fiber increased VFA concentrations in both the ileum (by 22%; P < 0.001), and the cecum (by 11%; P = 0.005). The relative gene expression of IL-6, IL-10, TNF-α, iNOS, MUC-1, and toll-like receptors (TLR-2 and TLR-4) in the cecal appendix increased linear and quadratically with increasing levels of cellobiose (P ≤ 0.063). In conclusion, in rabbits fed LSF diets, a dose of 7.5 g cellobiose/L drinking water would be recommended, whereas these levels of cellobiose supplementation should be avoided in rabbits fed HSF diets.

Effect of lactic acid bacteria-treated King grass silage on the performance traits and serum metabolites in New Zealand white rabbits (Oryctolagus cuniculus).

This study examined the effects of Lactobacillus plantarum and Pediococcus acidilactici-treated silage of King grass (Pennisetum purpureophoides) on the productive traits and blood biochemistry of New Zealand white (NZW) rabbits. King grass was ensiled without or with L. plantarum (T1), P. acidilactici (T2) and P. acidilactici + L. plantarum (T3). A total of 72 male NZW rabbits (6 weeks) of similar weight and appearance were housed in groups in metallic cages in a completely randomized design. The performance traits, daily feed intake, body weight gain and feed convention ratio were not affected by the silage treatment. Triglyceride and alanine aminotransferase (ALT) concentration was increased (p < .05) in T2 (0.92 mmol/L) compared to the other treatments. The superoxide dismutase (SOD), phosphorous (P) and magnesium (Mg) increased (p < .05) in T1 (658.01 nmol/ml, 5.1 mg/kg and 2.43 mg/kg, respectively) compared to the control and other experimental groups. Cu and Mn decreased (p < .05), while Zn increased (p < .05) in the treated groups compared to the control. The CP decreased (p < .05) in the treatment groups compared to the control. Neutral detergent fibre (NDF) increased (p < .05) in T2 (54.40%) compared to the other treatments. The inoculation of lactic acid bacteria-treated King grass silage supplementation positively affected rabbit performance and improved blood cholesterol profile, antioxidant status and improve nutrients digestibility.