Rabbit Diets Research Articles

The Effect of the BCO2 Genotype on the Expression of Genes Related to Carotenoid, Retinol, and α-Tocopherol Metabolism in Rabbits Fed a Diet with Aztec Marigold Flower Extract

This study investigated the effect of the BCO2 genotype and the addition of Aztec marigold flower extract to rabbit diets on the expression of BCO1, BCO2, LRAT, and TTPA genes in the liver. The levels of lutein, zeaxanthin, β-carotene, retinol, and α-tocopherol in the liver and blood serum of rabbits, as well as plasma biochemical parameters and serum antioxidant enzyme activities were also determined. Sixty male Termond White growing rabbits were divided into three groups based on their genotype at codon 248 of the BCO2 gene (ins/ins, ins/del and del/del); each group was divided into two subgroups: one subgroup received a standard diet, and the other subgroup was fed a diet supplemented with 6 g/kg of marigold flower extract. The obtained results indicate that the BCO2 genotype may affect the expression levels of BCO1 and BCO2 genes in rabbits. Moreover, the addition of marigold extract to the diet of BCO2 del/del rabbits may increase the expression level of the BCO2 gene. Finally, an increase in the amount of lutein in the diet of rabbits with the BCO2 del/del genotype contributes to its increased accumulation in the liver and blood of animals without compromising their health status or liver function.

Evaluation of Olive Leaves and Pomace Extracts in Growing Rabbit Diets on Productive Performance, Nutrient Digestibility, Carcass Characteristics, Antioxidant Status and Economic Efficiency

This study aimed to detect how supplementing olive leaves extract (OLE) and olive pomace extract (OPE) to growing rabbit diets has affected productive performance, nutrient digestibility, carcass characteristics, antioxidant status, and economic efficiency. At 42 days of age, 75 APRI growing rabbits were separated into five groups, 15 rabbits each. Control (without additives), OLE1 (200ppm of OLE), OLE2 (400ppm of OLE), OPE1 (200ppm of OPE), and OPE2 (400ppm of OPE) were the experimental diets. Throughout the trial, we computed feed consumption and increase in body weight on a weekly basis. Compared to the control group, the body weight, weight gain, and feed conversion ratio of rabbits fed OLE or OPE were significantly (P<0.05). The digestibility coefficient of crude protein-enhanced significantly (P<0.05) in rabbits fed OLE or OPE than in control rabbits. In addition to using OLE or OPE, the percentage of the carcass was improved dramatically (P<0.05). Total antioxidant capacity, Superoxide dismutase, and catalase levels were significantly (P<0.05) raised with OLE or OPE, while malondialdehyde levels were lowered. In conclusion, supplementing rabbit diets with 200 or 400ppm of OLE or OPE enhanced productive performance and antioxidant status without any negative effect on their health.

Effect of brown algae and natural antioxidants Supplementation in Growing Rabbit's Diet on Productive Performance and Economic Efficiency

Effect of brown algae and natural antioxidants Supplementation in Growing Rabbit's Diet on Productive Performance and Economic Efficiency

Effect of Green Algae and Natural Antioxidant Additioin to the Growing Rabbit's Diet on Productive Performance and Economic Efficiency

Effect of Green Algae and Natural Antioxidant Additioin to the Growing Rabbit's Diet on Productive Performance and Economic Efficiency

Feeding silkworm (Bombyx mori L.) oil to growing rabbits improves the fatty acid composition of meat, liver and perirenal fat

Silkworm oil was used in a rabbit diet to evaluate its benefit on the fatty acid (FA) profile of different carcass portions. Two experimental diets were prepared: a control diet (commercial diet with 13 g/kg sunflower oil) and a silkworm oil diet (SWO) (commercial diet with 13 g/kg silkworm oil). Rabbits received the experimental diets the last three weeks before slaughter, which occurred at 10 weeks of age. At slaughter, hind leg meat, liver, and perirenal fat were sampled for FA profile analysis. The SWO diet significantly increased the n-3 FA of all three sampling sites and halved the n-6/n-3 ratio of hind leg meat and perirenal fat. Furthermore, the liver of SWO rabbits was also richer in C22:6 n-3 compared to that of control rabbits. In conclusion, this study demonstrated that the total dietary replacement of sunflower oil with silkworm oil in fattening rabbits positively changed the FA profile of the considered carcass tissues.

Growth Performance, Semen Quality and Health Status as Affected by using Panicum Maximum in Rabbits Feed

The purpose of this study was to investigate replacement of clover hay in rabbit diets with Panicum maximum hay (Pmh) and how affected digestibility, growth performance, carcass characteristics, semen quality, economic efficiency, and health status. A total of 60 New Zealand White weaned male rabbits, aged 6 weeks and weighing an average of 720±42g, were randomly classified into four dietary groups (15 rabbits each). The control group was fed a baseline diet with 36% clover hay (D1). The other three groups were provided diets with 12, 24, and 36% Pmh to replace the clover hay in the basal diet (D2, D3, and D4 respectively). Feed intake, digestibility, CF and NFE, nutritive value (TDN and DE), daily body weight gain, FCR, and carcass percentage all decreased slightly (P<0.05) with increasing Pmh replacement up to 24 percent (D2 and D3) and significantly (P<0.05) with the highest replacement level (D4) when compared to the control. A replacement had no significant effect on semen quality. Replacement, on the other hand, increased net income by increasing Pmh levels as a result of lower overall feed costs, and the highest replacement level provided the best relative economic efficiency compared to control (114%). The hematological parameters were within normal limits and the histological alterations had no negative effect on the animals' physiological activities. Finally, using Pmh instead of clover hay in rabbit diets can be used as an alternative, save and more economical feed in rabbit diets.

Dietary effects of enzymolytic soybean meal inclusion on antioxidant capacity, intestinal morphology and caecal microbiota of Rex rabbits

The aim of this study was to evaluate the effect of enzymolytic soybean meal (ESBM) on antioxidant capacity, intestinal morphology and caecal microbiota in Rex rabbits. One-hundred-twenty 40-day-old healthy Rex rabbits were randomly divided into four groups with thirty replicates in each group and one rabbit per replicate. The control group was fed the basal diet and the ESBM treated groups (T1, T2 and T3) were fed 0.5%, 1% and 1.5% ESBM instead of the equivalent amount of soybean meal (SBM) in the basal diet, respectively. The study lasted 61 days, including a pre-feeding period of 5 days and a formal trial period of 56 days. Compared with the control group, the activity of superoxide dismutase and glutathione peroxidase in the liver, as well as total antioxidant capacity were significantly increased in the T3 group (p < 0.05). The malondialdehyde concentrations in the liver and jejunum were significantly decreased in the T1 group (p < 0.05). There were no significant differences in the antioxidant capacity of jejunum, intestinal morphology index and intestinal pH among all groups (p > 0.05). Compared with the control group, the relative abundance of Ruminococcaceae_UCG-013 was increased significantly in both T2 and T3 groups (p < 0.05), and the relative abundance of Ruminococcaceae_unclassified was decreased significantly in all treatment groups (p < 0.05). In conclusion, the replacement of equivalent amounts of SBM with ESBM in the diet of Rex rabbits can increase the antioxidant capacity of the liver and improve the caecal microbiota, and the optimal replacement level was 1.5%. HIGHLIGHTS Enzymolytic soybean meal (ESBM) increased the liver antioxidant capacity of Rex rabbits. ESBM improved the caecal microbiota of Rex rabbits. Effects of ESBM on the intestinal morphology and pH of Rex rabbits were evaluated.

Blood parameters of rabbits given different amounts of iodine citrate

The need for iodine in rabbit diets has not been fully elucidated, although some commercial diets use it in varying amounts without scientific justification. The main goal of the experiment was to establish the effect of applied quantities of an organic iodine compound produced by nanotechnology – iodine citrate – on blood parameters of rabbits after weaning from 40 to 96 days of age. Experimental studies were conducted in the conditions of the vivarium of the scientific institution – Institute of Animal Biology of the National Academy of Sciences of Lviv on 30 rabbits of the Termonska breed. The control and experimental groups had the same number of 6 animals, of which 3 were males and 3 were females. Young rabbits of the control group were kept on standard granulated compound feed and water without restriction. In contrast to the control, the animals of I, II, III, and IV experimental groups additionally received a solution of iodine citrate in the amount of 2.5; 3.75; 5.0 and 7.5 μg/l of water, respectively. Blood parameters were determined on the 40th day of life (preparatory period) and on the 18th, 43rdБ and 56th days of iodine citrate supplementation. Studies have established a higher number of red blood cells and haemoglobin concentration in the blood of rabbits of Group II (P≤0.05) on the 43rd and 56th days; Group III (P≤0.05) and Group IV (P≤0.05-0.01) on the 18th, 43rd, and 56th days of the study. The haematocrit value of the blood of rabbits of Group II was respectively higher by 16.6% on the 56th day; Group III – by 17.1%; 20.0%, and 22.8%, and in Group IV – by 26.4%; 29.4%, and 23.5% on the 18th, 43rd, and 56th days of the study. The albumin content in the blood of rabbits of Group I was higher by 4.1% on the 43rd day; Group II – by 6.8%; 8.0%; 9.5%; Group III – by 6.1%; 4.6%; 9.5%; Group IV – by 4.5%; 2.7%; 7.3% on the 18th, 43rd, and 56th days of the study, respectively. The content of total calcium in the blood of rabbits of Group II exceeded the control by 22.5% on day 43, the level of inorganic phosphorus in the blood of rabbits of Groups II, III, and IV was respectively higher by 5.8%, 5.0%, and 4.1% on the 56th day of the study compared to the control.

Effects of GH on the Aging Process in Several Organs: Mechanisms of Action.

In order to investigate the possible beneficial effects of GH administration on the aging process, 24-month-old rats of both sexes and 10-month-old SAMP8 mice were used. Male rats showed increased fat content and decreased lean body mass together with enhanced vasoconstriction and reduced vasodilation of their aortic rings compared to young adult animals. Chronic GH treatment for 10 weeks increased lean body mass and reduced fat weight together with inducing an enhancement of the vasodilatory response by increasing eNOS and a reduction of the constrictory responses. Old SAMP8 male mice also showed insulin resistance together with a decrease in insulin production by the endocrine pancreas and a reduced expression of differentiation parameters. GH treatment decreased plasma levels and increased pancreatic production of insulin and restored differentiation parameters in these animals. Ovariectomy plus low calcium diet in rabbits induced osteoporosis Titanium implants inserted into these rabbit tibiae showed after one month lesser bone to implant (BIC) surface and bone mineral density (BMD). Local application of GH in the surgical opening was able to increase BIC in the osteoporotic group. The hippocampus of old rats showed a reduction in the number of neurons and also in neurogenesis compared to young ones, together with an increase of caspases and a reduction of Bcl-2. GH treatment was able to enhance significantly only the total number of neurons. In conclusion, GH treatment was able to show beneficial effects in old animals on all the different organs and metabolic functions studied.

Soybean oil and selenium yeast levels in the diet of rabbits on performance, fatty acid profile, enzyme activity and oxidative stability of meat

The objective was to evaluate the effectiveness of selenium yeast (Se, 0 and 0.15 mg/kg) as an antioxidant agent and its incorporation into meat when associated with different levels of soybean oil (SO, 1.5% and 3.0%) in the diet of rabbits. Rabbit meat was evaluated for chemical composition, fatty acid profile, enzymatic activity and oxidative stability. The increase in the soybean oil level promoted better incorporation of selenium in the meat. The 3.0% SO level improved the fatty acid profile of the meat, promoting a better saturated/unsaturated ratio and increased linoleic acid deposition. Malondialdehyde values in meat were affected by storage time and by the addition of selenium in the diet. Thus, the higher SO levels contributed to improve the saturated/unsaturated fatty acid ratio, which was directly influenced by the meat storage time. On the other hand, supplementation with Se yeast promoted better elongase enzyme activity, aiding in the production of eicosanoic acid and decreased lipid oxidation of rabbit meat.

The effect of barnacles powder as a source of protein feed substitution against the digestibility of crude protein and crude fiber on male rabbits rex

The aim of this study was to determine the effect of barnacle powder as a feed substitution in diet on digestibility of crude protein and crude fiber in 100 rex male rabbits. It was an experimental study using a completely randomized design with four treatments and five replications. The substitution of barnacle flour was given for four weeks and each diet was 0%, 2.5%, 5%, 7.5%. Data collection was carried out in the fourth week (for seven days) which included data on consumption, manure weight and analysis of treated feed and manure analysis. The data were analyzed using analysis of variance and Duncan test. The average crude protein digestibility (%) of P0, P1, P2, and P3 for each treatment were 76.84±0.81; 76.45±1.41; 76.09±0.60; and 77.47±1.01. The results showed that there were no significant differences (p> 0.05) in crude protein digestibility but the results showed a significant difference (p> 0.05) in crude fiber digestibility. The average crude fiber digestibility (%) of P0, P1, P2, and P3 for each treatment were 36.67±2.86; 50.81±1.57; 49.42±1.30; and 45.93±2.77. It showed that substitution of barnacle flour in diet can replace the source of protein in fish meal for the complete diet of rabbits.

Influence of dietary organic acid, probiotic and antioxidant on the growth performance and nutrient digestibility in growing rabbit

This study was conducted to compare the effects of different feed additives namely, organic acid (citric acid), probiotic (navio plus), and antioxidant (Bio-Sel-E) on the growth performance and nutrient digestibility in growing rabbit to convey a clear message on the use of one specific additive in rabbit diet. Thirty-two crossbred New Zealand White growing rabbit (four to five weeks of age) were randomly assigned to four different groups and reared for a period of fifty six days. Rabbit were fed on green grass (Hymenachne pseudointerrupta) and concentrate mixture (2703 Kcal ME/kg, 16.91 % CP). Additives were added at the top of the concentrate mixture, except for the control group. Compared with the control group, rabbit fed different additives showed 9–13% higher growth rate and 7–11% greater growth velocity; and probiotic supplemented group showed the best result (P&lt;0.05) in terms of FCR value. Carcass weight (%) increased significantly in probiotic supplemented group, but numerically in organic acid and antioxidant supplemented groups compared with control group. Abdominal fat (%) was significantly decreased in organic acid, probiotic and antioxidant supplemented groups compared with control, however, lowest value (%) was recorded in probiotic supplemented group. Probiotic showed significant effect on pH decreasing trend in ingesta sample up to small intestine. Crude protein digestibility co-efficient (%) value was significantly higher in probiotic supplemented group, but numerically in organic acid and antioxidant supplemented groups compared with control group. Overall results indicated that, among the three different additives: organic acid, probiotic and antioxidant, probiotic may be considered as the best one for the better performance and nutrient digestibility in growing rabbit.&#x0D; Bangladesh Journal of Animal Science, 51 (2): 55-61.

English

The performance of twenty four 6-8 week old apparently healthy male and female weanling rabbits of mixed breed fed diets treated with aflatoxin, which contained 5% sweet orange (Citrus sinensis) fruit peel meal was evaluated in an 8 week feeding trial. Sweet orange peels were collected from orange sellers, sun-dried and milled. Fungal strain of Aspergillus flavus was cultured and inoculated into groundnut cake to produce aflatoxin using solid state fermentation method. Treated groundnut cake was incubated for seven days with incremental incubation temperature from 20-25 &ordm;C The groundnut cake was autoclaved, milled and, aflatoxin extracted from 10 g sample of the milled cake with 50 ml chloroform, and its concentration quantified by Thin Layer Chromatography (TLC). Treated groundnut cake was included at 0, 50, 100 and 150 gram in grower rabbit diets to produce diets T1, T2, T3 and T4, having 0 ppb, 50 ppb, 100 ppb and 150 ppb aflatoxin, respectively. The rabbits were randomly allocated to four diets at the rate of six per diet, housed singly in rabbit hutches, fed and served water free choice. The result showed significant (P&lt;0.05) negative effect&nbsp; of diets on final live weight, weight gain, feed intake, feed conversion ratio, water consumption, protein intake and protein efficiency ratio as the dietary aflatoxin increased from 0 ppb to 150 ppb. Also, diets had significant (P&lt;0.05) negative effect on dressed weight and carcass length and, kidney. Total aflatoxin residue varied significantly (P&lt;0.05) from 0 &mu;g/kg - 2.76&mu;g/kg,&nbsp; 0 &mu;g/kg - 1.94&mu;g/kg and 0 &mu;g/kg - 0.85&mu;g/kg for liver, kidney and meat tissue, respectively as the dietary aflatoxin increased from 0 ppb to 150 ppb. Performance response of rabbits was affected negatively by aflatoxin, thereby showing the inability of 5% dietary inclusion of sweet orange (Citrus sinensis) peel meal to mitigate the adverse consequences of aflatoxin intake by rabbit. Key words: Growth responses, residual level, visceral organs, mitigate.

Enterocin 7420 and Sage in Rabbit Diet and Their Effect on Meat Mineral Content and Physico-Chemical Properties.

Rabbit meat has outstanding nutritional characteristics—it is a lean meat with low fat, cholesterol and sodium content, with high-biological-value proteins, potassium, phosphorus, selenium, iron and vitamin B12 level. The dietary inclusion of natural bioactive compounds can improve the quality of rabbit meat. The present study evaluated the effect of enterocin 7420 (Ent 7420) and sage (Salvia officinalis) extract on the quality and mineral content of rabbit meat. A total of 96 Hyla rabbits (aged 35 days) were divided into E (Ent 7420; 50 µL/animal/d), S (sage extract; 10 µL/animal/d), E + S (Ent 7420 and sage in combination) and control (C) groups. Additives were administrated in drinking water for 21 days. A significant increase in meat iron (p < 0.01) content was noted; phosphorus and zinc levels were also elevated in experimental groups, compared with control data. Ent 7420 and sage treatment reduced the calcium and manganese (p < 0.01) contents. The physico-chemical traits of rabbit meat were not negatively influenced by treatment. Based on these results, diet supplementation, mostly with Ent 7420 but also in combination with sage, could enhance the quality of rabbit meat mineral, with a focus on its iron, phosphorus and zinc contents.

English

The aim of the study was to evaluate the physiological performance of heat stressed growing rabbits fed diets supplemented with vitamin anti-oxidants and bicarbonate buffers. A total of thirty (30) growing rabbits (New Zealand White crosses) of two months old were used in this study. There were six (6) rabbits per treatment in a Completely Randomized Design (CRD). The treatment groups consisted of: control, sodium bicarbonate (NaHCO3) and potassium bicarbonate, (KHNO3) solution respectively, Vitamin C, and baobab fruit pulp meal (BFPM) as supplements, respectively. The experiment lasted for 9 weeks. Five milliliters of blood were collected from five rabbits (through the ear vein) chosen randomly from each group of rabbits, respectively at the beginning and the end of the experiment for serum metabolite and thyroxine hormone evaluation. Physiological performance of the rabbits was also evaluated.&nbsp;It was found that environmental conditions were stressful to the animals; Vitamins (Vit C and BFPM) significantly (P&lt;0.05) reduced rectal temperature, heart rate and triglycerides compared to other treatments. The buffers recorded significantly (P&lt;0.05) high feed intake, calcium and thyroxine. It was concluded that ameliorating heat stress with the antioxidants were helpful to improve the performance of rabbits and was recommended to be included in rabbit diets during the hot period. &nbsp; Key words: Antioxidants, buffers, heat stress, thyroxine.

Expression of concern “Supplementing rabbit diets with butylated hydroxyanisole affects oxidative stress, growth performance, and meat quality” [Animal 15(9) (2021) 100339

Expression of concern “Supplementing rabbit diets with butylated hydroxyanisole affects oxidative stress, growth performance, and meat quality” [Animal 15(9) (2021) 100339

Hematological and biochemical parameters and resistance of the organism of mother rabbits receiving sulfur compounds

Nanotechnologies are developing continuously, and their use is becoming more diverse and concrete, with high potential to improve the products of animal husbandry and animals in general. Yet, there have been few studies of nanotechnologies in those spheres. However, to confirm the efficiency and, mainly, safety of nanotechnologies, to avoid any harm to the environment or especially humans and animals, substantiated studies are still needed. A promising, but barely studied, direction of research is dosage of nanocompounds of biogenic elements in diets of animals, both modern supplements and alternatives for correcting mineral nutrition. Therefore, the objectives of the study presented here were changes in hematologic, biochemical and immune-biological parameters of the organism of mother rabbits under the influence of sulfur citrate and sodium sulfate for 14 days until insemination and until day 20 of lactation. The research was conducted on mother rabbits of the Hyla breed which were giving birth for the second time in LLC Horlytsia in Dobriany village of Horodok district of Lviv Oblast. Mother rabbits of the control group were fed ad libitum with complete granulated mixed feed with free access to water. Animals of experimental group I were fed feeds of the diet of the control group and during the day were watered sulfate citrate in dosage of 8 µg of S/kg of body weight. Females of experimental group II were fed the diet feeds of the control group and given sodium sulfate (Na2SO4) in the amount of 40 mg of S/kg of body weight. The mother rabbits received the supplements for 14 days both until insemination and for up to the 20th day of lactation. In the preparation period, on day 10 after the beginning of the study and on day 20 of lactation in the experimental period (65th day of watering the supplements), blood samples were taken from the marginal ear vein of the mother rabbits for hematological and biochemical studies. The study revealed that watering sulfate citrate in the dosage of 8 µg of S/kg of the body weight in the diet of mother rabbits for 14 days until insemination and up to day 20 of lactation increased the amount of erythrocytes by 19.5%, leukocytes by 37.5%, granulocytes by 38.3%, concentration of hemoglobin by 21.0%, mean corpuscular hemoglobin by 15.6%, and red cell distribution width by 14.7%, and activated protein metabolism, which manifested in 8.5% higher content of protein and activity of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase respectively by 12.9%, 29.6%, 19.8% and 51.8% lower content of triacylglycerols in the blood on day 20 of lactation compared with the control group. Intake of sulfur citrate heightened the parameters of immunobiological reactivity of the organisms of mother rabbits on day 65 of the experiment with significantly higher level of phagocytic number, phagocytic activity, lysozymic and bactericidal activities of blood serum, protein-associated hexoses, sialic acids and ceruloplasmin and immune globulins, compared with the control. Giving mother rabbits sodium sulfate in the amount of 40 mg/kg of body weight for 65 days led to less notable changes in the blood, expressed in 20.0% increase in mean corpuscular hemoglobin, higher phagocytic value, phagocytic activity, lysozymic and bactericidal activities of blood serum, protein-associated hexoses and ceruloplasmin. The results of the studies indicate possibility of additional use of supplement sulfur citrate in the amount of 8 µg of S/kg in diet of mother rabbits to improve metabolism, reproductive ability and immunological resistance in the period of increased physiological load.

Spatiotemporal changes of local hemodynamics and plaque components during atherosclerotic progression in rabbit

Background and objectiveRecent evidence demonstrates that the atherogenic process is discontinuous. Our goal is to study changes of plaque components and local hemodynamics during atherosclerotic progression. MethodsThe histological and immunohistochemical staining of high-fat diet rabbit aorta were evaluated at 0, 8, 10 and 12 weeks, respectively. In addition, the blood flow and LDL transport were simulated at the above four time points. ResultsThe plaque thickness at different characteristic regions increased at different rates. The collagen continued to increase, while the elastin, fibronectin, macrophages and smooth muscle cells increased first and then decreased. The relative surface LDL concentration decreased at 8 weeks, and then it increased first and decreased slightly. Meanwhile, the hemodynamic environment became better firstly at 8 weeks, then got slightly worse and lastly improved again. ConclusionsThe local hemodynamics and plaque components vary nonlinearly during atherosclerotic progression in rabbit aorta.

The Effect of Exogenous Lysozyme Supplementation on Growth Performance, Caecal Fermentation and Microbiota, and Blood Constituents in Growing Rabbits.

Simple SummaryRabbit farming is increasingly requiring non-antibiotic alternatives to improve rabbit gut health to maintain high feeding efficiency and excellent production index. Thus, using a friendly alternative is an appropriate way to protect rabbits from pathogens while also enhancing their performance and welfare. Lysozyme, an enzyme derived from avian egg white, aids in nutrient digestion and absorption and provides protection against bacterial diseases while lowering pollutants’ excretion, such as ammonia. Thus, the aim of this study was to evaluate the effect of lysozyme supplementation in rabbits’ diets on growth performance, caecal fermentation, bacteria population, and blood constituents. The results demonstrated an improvement in rabbit performance, caecal fermentation, blood lipid profile, and antioxidant status due to an increase in beneficial bacteria in lysozyme-treated rabbits. Therefore, supplementing the rabbit diet with lysozyme up to 150 mg/kg is recommended.The effects of exogenous lysozyme supplementation (LYZ) on growth performance, caecal fermentation and microbiota, and blood characteristics were investigated in growing rabbits. A total of 420 growing male V-Line rabbits (30 d old; weighing 528 ± 16 g) were randomly divided into four groups of 105 rabbits each, and monitored for 42 days. Experimental groups included a control group (LYZ0) fed a basal diet without LYZ supplementation, and three treated groups fed the same basal diet supplemented with LYZ at 50, 100, and 150 mg/kg diet, respectively. The results showed a quadratic improvement in the final body weight, daily growth rate, FCR, and digestibility of DM, while the digestibility of OM, CP, EE, NDF, and ADF improved linearly when LYZ supplementation was increased. The dressing percentage increased quadratically when LYZ levels were increased in the rabbit diets. In rabbits fed LYZ diets, L. acidophilus counts increased linearly (p < 0.05) and L. cellobiosus, and Enterococcus sp. counts increased quadratically, whereas E. coli counts decreased. In the LYZ-supplemented groups, the caecal pH value and NH3-N concentration declined quadratically, whereas total VFA, acetic, and butyric acids increased. Total lipids decreased linearly, whilst triglycerides and cholesterol decreased quadratically with LYZ supplementation. Total antioxidant capacity, superoxide dismutase, glutathione S-transferase, and catalase increased quadratically, while malondialdehyde decreased linearly in the LYZ-supplemented groups. In conclusion, exogenous lysozyme administration improved rabbit growth performance and antioxidant status while lowering the blood lipid profile, altering the bacterial population, and regulating caecal fermentation. Therefore, LYZ up to 150 mg/kg can be used as a potential supplement in rabbit feed.

Gut Microbiota Modulate Rabbit Meat Quality in Response to Dietary Fiber.

Antibiotics are widely used in gastrointestinal diseases in meat rabbit breeding, which causes safety problems for meat products. Dietary fiber can regulate the gut microbiota of meat rabbits, but the mechanism of improving meat quality is largely unknown. The objective of this study was to evaluate the effects of adding different fiber sources to rabbit diets on the growth performance, gut microbiota composition, and muscle metabolite composition of meat rabbits. A total of 18 New Zealand white rabbits of similar weight (40 ± 1 day old) were randomly assigned to beet pulp treatment (BP), alfalfa meal treatment (AM), and peanut vine treatment (PV). There were 6 repeats in each treatment and all were raised in a single cage. The predictive period was 7 days and the experimental period was 40 days. The results revealed that AM and PV supplementation increased growth performance, slaughter performance, and intestinal development of meat rabbits compared with the BP treatment, and especially the effect of AM treatment was better. The content of butyric acid was increased in PV and AM treatments compared with the BP treatment. The expression of mitochondrial biosynthesis genes of liver, cecum, and muscle showed that AM treatment increased gene expression of CPT1b compared to the BP treatment. In addition, AM and PV treatments significantly increased the microbial diversity and richness compared with BP treatment, and their bacterial community composition was similar, and there were some differences between AM and PV treatments and BP treatment. Metabonomics analysis of muscle showed that AM treatment significantly increased amino acid and fatty acid metabolites compared with BP treatment, which were mainly concentrated in energy metabolism, amino acid metabolism, and fatty acid regulation pathways. Furthermore, through correlation analysis, it was found that there was a significant correlation between rumenococci in the cecum and amino acid metabolites in the muscle. Overall, these findings indicate that AM may affect the body's health by changing its gut microbiota, and then improving meat quality, and the intestinal–muscle axis provides a theoretical basis.