A cross-sectional retrospective study of SARS-CoV-2 seroprevalence in domestic cats, dogs and rabbits in Poland.

BACKGROUND: Coronaviruses (CoVs) have long been known to cause infection in domestic and free-living birds and mammals including humans. The zoonotic origin of SARS-CoV-2 and the biological properties of CoVs, including ability to cross interspecies barriers, enable its emergence in populations of various animals, including companion animals (cats, dogs, rabbits) an area requiring further study. To date, several cases of cats and dogs positive for SARS-CoV-2 and/or specific antibodies have been described. The aim of our cross-sectional retrospective study is to determine seroprevalence of SARS-CoV-2 in domestic dog, cat and rabbit population during recent COVID-19 pandemic in Poland. RESULTS: In total, serum samples from 279 cats and 343 dogs and 29 rabbits were used in the study. The seroprevalence of SARS-CoV-2 in cats and dogs reached 1.79% (95% CI: 0.77 - 4.13) and 1.17% (95% CI 0.45 - 2.96), respectively (p ≥ 0.05). Anti- SARS-CoV-2 antibodies were detected in 5 cats (mean S/P% 106 ± 48.23) and 4 dogs (mean S/P% 78.5 ± 16.58). All 29 samples from rabbits were negative for SARS-CoV-2 antibodies. No significant gender or age differences in seroprevalence in dogs and cats (p ≥ 0.05) were found. None of the animals with anti-SARS-CoV-2 antibodies displayed respiratory or gastrointestinal signs at the time of sampling. CONCLUSIONS: Our results confirmed previous findings that SARS-CoV-2 infections in companion animals occurs but are not frequent. Future serological testing of large pet population may provide a comprehensive picture of disease dynamics in companion animals.

Different metabolites induced by deoxynivalenol in the serum and urine of weaned rabbits detected using LC-MS-based metabolomics.

The main toxic effects of deoxynivalenol (DON) are the result of long-term accumulation, and there are no obvious clinical signs at the early stage. Specific metabolites in blood and urine can be used as biomarkers and become an important diagnostic indicator for DON poisoning monitoring. This study aimed to reveal the differences in DON-induced metabolites in the serum and urine of weaned rabbits. Thirty-two weaned rabbits were divided into two groups: control group and DON group. Both groups of rabbits were fed a basic diet. Rabbits in the DON group were administered 1.5 mg/kg b.w. DON by intraperitoneal injection on an empty stomach in the morning every two days. Rabbits in the control group were injected with the same amount of saline every two days in the same way. After the 25-day trial, serum and urine samples from different experimental periods were collected. The results based on the LC-MS/MS method showed that DON can be metabolized rapidly in blood, and urine is the main metabolic pathway for DON. Data based on metabolomics illustrated that underlying biomarkers in serum were mainly involved in glycerophospholipid metabolism, tryptophan metabolism and pentose and glucuronate interconversions, while those in urine samples were involved in caffeine metabolism, glycine, serine and threonine metabolism, and terpenoid backbone biosynthesis. Correlation analysis suggested that DON can induce changes in certain disease-related metabolites in serum and urine. In conclusion, the pathogenic mechanism of DON includes multiple levels, indicating that DON poisoning is caused by multiple factors acting on multiple links.

The effect of dietary supplementation with silkworm pupae meal on gastrointestinal function, nitrogen retention and blood biochemical parameters in rabbits.

BACKGROUND: The aim of this study was to determine the effect of dietary inclusion of silkworm pupae meal (SPM) on nutrient digestibility, nitrogen utilization, gastrointestinal physiology and blood biochemical parameters in rabbits. Thirty Termond White rabbits were divided into three groups: SBM - fed a diet containing 10% soybean meal (SBM), SPM5 - fed a diet containing 5% SBM and 5% SPM, and SPM10 - fed a diet containing 10% SPM. RESULTS: Nutrient digestibility and nitrogen retention decreased with increasing SPM inclusion levels in rabbit diets. The dietary inclusion of SPM caused a significant increase in the stomach pH. Group SPM10 rabbits were characterized by the highest cecal tissue and digesta weights. The lowest cecal pH was noted in group SPM5. The relative weights of colonic tissue and digesta tended to increase with increasing levels of SPM. The total and intracellular activity of bacterial α-galactosidase decreased significantly in both SPM groups. The replacement of SBM with SPM led to a decrease in the activity of bacterial ß-glucuronidase in the cecal digesta. The intracellular activity of bacterial α-arabinofuranosidase increased, and its release rate decreased in the cecum of rabbits in SPM groups. The extracellular activity of bacterial ß-xylosidase in the cecal digesta tended to decrease in group SPM10. The highest extracellular and intracellular activity of bacterial ß-cellobiosidase in the cecal digesta was noted in the SPM5 treatment. The lowest and the highest activity of bacterial N-acetyl-ß-D-glucosaminidase (NAGase) was observed in groups SBM and SPM10. The SPM10 treatment contributed to a decrease in the cecal concentrations of butyric, iso-valeric and valeric acids. The lowest total concentration of putrefactive short-chain fatty acids (PSCFAs) was observed in group SPM10. The cecal concentration of propionic acid tended to increase in group SPM5, whereas the cecal concentration of iso-butyric acid tended to decrease in group SPM10. The colonic concentration of iso-valeric acid was lowest in group SPM5. SPM treatments resulted in a significant increase in plasma albumin concentration. Plasma urea concentration was significantly higher in group SPM10 than in SBM and SPM5. CONCLUSIONS: The results of this study suggest that rabbit diets can be supplemented with SPM at up to 5%.

Evaluation on two types of paramyosin vaccines for the control of Haemaphysalis longicornis infestations in rabbits.

BACKGROUND: Haemaphysalis longicornis is an obligate hematophagous ectoparasite that transmits a variety of pathogens causing life-threatening diseases in humans and animals. Paramyosin (Pmy) is not only an invertebrate-specific myofibrillar protein but also an important immunomodulatory protein. Therefore, it is one of the ideal candidate antigens for vaccines. METHODS: We conducted two vaccine trials to evaluate the protective efficacy of Pmy recombinant protein (rPmy) and peptide vaccine (KLH-LEE). Each rabbit was immunized with three doses of rPmy or KLH-LEE adjuvanted with Freund's complete/incomplete at 500 µg/dose at 2-week intervals before challenge with 40 female H. longicornis/rabbit. PBS plus adjuvant, Trx or KLH was used as control group. The antibodies of rabbits were detected by ELISA. Then, female ticks were fed on the rabbits until detachment. RESULTS: ELISA results showed that both vaccines induced rabbits to produce antibodies. Compared with the Trx group, the engorgement weight, oviposition and hatchability of the rPmy group decreased by 8.87%, 26.83% and 38.86%, respectively. On the other hand, engorgement weight, oviposition and hatchability of female ticks in the KLH-LEE group correspondingly resulted in 27.03%, 53.15% and 38.40% reduction compared with that of the KLH group. Considering the cumulative effect of vaccination on the evaluated parameters, results showed 60.37% efficacy of the rPmy vaccine formulation and 70.86% efficacy in the KLH-LEE group. CONCLUSIONS: Pmy and particularly epitope LEE have potential for further development of an effective candidate vaccine to protect the host against tick infection. GRAPHIC ABSTARCT.

Differential white blood cell counts in rabbits: a comparison of the Advia 2120 and a manual method.

We evaluated the performance of the Advia 2120 (Siemens) differential leukocyte count (A-Diff) compared to the manual method (M-Diff) in rabbits. EDTA-anticoagulated blood samples collected for diagnostic purposes were analyzed within 6 h of collection. The M-Diff was performed blindly by 2 observers on blood smears by counting 200 cells. We initially included 117 samples; 25 samples were excluded because of suboptimal gating of leukocytes in the Advia peroxidase cytogram or poor blood smear quality. The correlation between the A-Diff and M-Diff was very high for heterophils (r = 0.924, p < 0.001) and lymphocytes (r = 0.903, p < 0.001), high for basophils (r = 0.823, p < 0.001), moderate for monocytes (r = 0.645, p < 0.001), and low for eosinophils (r = 0.336, p = 0.001). The Passing-Bablok regression analyses revealed a small-to-moderate constant error for lymphocytes and a slight constant error for basophils. Small proportional errors were detected for heterophils, lymphocytes, and eosinophils. The Bland-Altman analyses revealed that the Advia significantly underestimates heterophils and overestimates lymphocytes compared to M-Diff. The biases for the other leukocytes were minimal and likely clinical insignificant; however, our results, particularly for eosinophils, should be interpreted cautiously given the observed low percentages in our samples. Given the observed biases in heterophil and lymphocyte percentages in the Advia 2120 CBC results in rabbits, method-specific reference intervals should be used. The Advia can recognize leporine basophils. Evaluation of blood smears is still recommended to investigate abnormal results and erroneous cytograms reported by the Advia.

Effect of host breeds on gut microbiome and serum metabolome in meat rabbits.

BACKGROUND: Gut microbial compositional and functional variation can affect health and production performance of farm animals. Analysing metabolites in biological samples provides information on the basic mechanisms that affect the well-being and production traits in farm animals. However, the extent to which host breeds affect the gut microbiome and serum metabolome in meat rabbits is still unknown. In this study, the differences in phylogenetic composition and functional capacities of gut microbiota in two commercial rabbit breeds Elco and Ira were determined by 16S rRNA gene and metagenomic sequencing. The alternations in serum metabolome in the two rabbit breeds were detected using ultra-performance liquid chromatography system coupled with quadrupole time of flight mass spectrometry (UPLC-QTOFMS). RESULTS: Sequencing results revealed that there were significant differences in the gut microbiota of the two breeds studied, suggesting that host breeds affect structure and diversity of gut microbiota. Numerous breed-associated microorganisms were identified at different taxonomic levels and most microbial taxa belonged to the families Lachnospiraceae and Ruminococcaceae. In particular, several short-chain fatty acids (SCFAs) producing species including Coprococcus comes, Ruminococcus faecis, Ruminococcus callidus, and Lachnospiraceae bacterium NK4A136 could be considered as biomarkers for improving the health and production performance in meat rabbits. Additionally, gut microbial functional capacities related to bacterial chemotaxis, ABC transporters, and metabolism of different carbohydrates, amino acids, and lipids varied greatly between rabbit breeds. Several fatty acids, amino acids, and organic acids in the serum were identified as breed-associated, where certain metabolites could be regarded as biomarkers correlated with the well-being and production traits of meat rabbits. Correlation analysis between breed-associated microbial species and serum metabolites revealed significant co-variations, indicating the existence of cross-talk among host-gut microbiome-serum metabolome. CONCLUSIONS: Our study provides insight into how gut microbiome and serum metabolome of meat rabbits are affected by host breeds and uncovers potential biomarkers important for breed improvement of meat rabbits.

Effect of rest temperature on rotational thromboelastometry in New Zealand White rabbits.

With the increasing popularity of viscoelastic coagulation analyzers, such as rotational thromboelastometry [ROTEM] and thromboelastography, the need for standardized methodology for appropriate interpretation has become increasingly important. Viscoelastic analysis is heavily influenced by a multitude of pre-analytic factors, both in vivo and in vitro, leading to a large amount of variation between institutions. We investigated the effect of room temperature during a 30-min sample rest time on ROTEM, which analyzed both intrinsic and extrinsic pathways. We also evaluated the feasibility of using ROTEM to assess coagulation in non-anesthetized domestic rabbits. Rabbits were selected because they are a common companion animal that could benefit from the use of viscoelastic analysis for various disease processes that could lead to coagulopathies. Citrated whole blood was collected from 10 rabbits and allowed to rest upright for 30 min either at room temperature (~ 21°C) or in a tube warmer (37°C) before analysis. There was no significant difference in results between room temperature and warmed samples, which suggests that allowing samples to rest at room temperature is acceptable clinically. Additionally, blood collection and analysis were feasible in all rabbits.

Using arterial blood as a substitute for venous blood in routine biochemistry parameter examinations in rabbits.

BACKGROUND: It has been widely accepted that there is a significant difference in peripheral blood oxygen between arteries and veins. Therefore, arterial blood has been collected for blood gas analysis, and venous blood, because it is convenient to collect, has been used for most laboratory examinations. However, venous blood is always difficult to collect in rabbits; in contrast, arterial blood is easier to obtain, and research on whether arterial blood can be used instead of venous blood for routine biochemical parameter examination is rare. Therefore, the present study was designed to explore whether arterial blood can be used as a substitute for venous blood for routine biochemistry parameter examination in rabbits. RESULTS: Three venous blood samples with gross hemolysis were excluded. Venous and arterial blood samples were obtained from forty-two rabbits. Arterial blood samples correlate well with venous blood in alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (GGT), total protein (TP), globulin (GLB), serum total cholesterol (TC), serum triglyceride (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), urea (Ur) and creatinine (Cr) levels by Deming regression analysis with slopes ranging from 0.893 to 1.176 and intercepts ranging from - 4.886 to 5.835. Bland-Altman analysis showed that the two sample parameters had 93%-98% of the points within the 95% consistency limits. There were significant differences between venous blood and arterial blood in ALP, TP, TC, TG, HDL, LDL and Cr, while AST, ALT, GGT, GLB and Ur showed no significant differences. CONCLUSIONS: Arterial blood can be a substitute for venous blood in routine biochemistry parameter examinations in rabbits, especially in situations where venous blood is difficult to collect.

Comparison of 2 portable human glucometers for the measurement of blood glucose concentration in White New Zealand rabbits.

We compared measurements of blood glucose concentrations in 30 healthy adult White New Zealand rabbits using 2 commercial portable glucometers (PGM1 and PGM2) and a laboratory chemical analyzer. Results were analyzed with Pearson correlation, Passing-Bablok regression analysis, Bland-Altman analysis, and a modified error grid. Measurements with PGM1 were significantly correlated (r = 0.37) with those obtained from the laboratory reference method (RM); Bland-Altman and Passing-Bablok analyses indicated no significant systematic or proportional differences (mean difference of -0.26, 95% CI of mean difference of -0.54 to 0.01, and LOA of -1.70 to 1.17); and error grid resulted in 100% of measurements in zone A. No significant correlation (r = -0.05) was detected between PGM2 and RM; Bland-Altman and Passing-Bablok analyses results indicated a mean difference of 2.14, 95% CI of mean difference of 1.67-2.60, and limit of agreement of -0.32 to 4.59, which overestimated blood glucose concentration, with 53% of glucose measurements in error grid zone A and 47% in zone B. PGM1 was considered accurate in normoglycemic rabbits, whereas the use of PGM2 could result in overestimations of glycemia.

Pharmacokinetics and bioavailability of tildipirosin in rabbits following single-dose intravenous and intramuscular administration.

The objective of this study was to determine the pharmacokinetics of tildipirosin in rabbits after a single intravenous (i.v.) and intramuscular (i.m.) injection at a dose of 4 mg/kg. Twelve white New Zealand rabbits were assigned to a randomized, parallel trial design. Blood samples were collected prior to administration and up to 14 days postadministration. Plasma concentrations of tildipirosin were quantified using a validated ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. The pharmacokinetic parameters were calculated using a noncompartmental model in WinNonlin 5.2 software. Following i.v. and i.m. administration, the elimination half-life (T1/2λ ) was 81.17 ± 9.28 and 96.68 ± 15.37 hr, respectively, and the mean residence time (MRTlast ) was 65.44 ± 10.89 and 67.06 ± 10.49 hr, respectively. After i.v. injection, the plasma clearance rate (Cl) and volume of distribution at steady state (Vdss ) were 0.28 ± 0.10 L kg-1  h-1 and 17.78 ± 5.15 L/kg, respectively. The maximum plasma concentration (Cmax ) and time to reach maximum plasma concentration (Tmax ) after i.m. administration were 836.2 ± 117.9 ng/ml and 0.33 ± 0.17 hr, respectively. The absolute bioavailability of i.m. administration was 105.4%. Tildipirosin shows favorable pharmacokinetic characteristics in rabbits, with fast absorption, extensive distribution, and high bioavailability. These findings suggest that tildipirosin might be a potential drug for the prevention and treatment of respiratory diseases in rabbits.

B and T lymphocytes in rabbits change according to the sex and throughout the year.

The European rabbit (Oryctolagus cuniculus) is a good model in biomedicine used in research on several human diseases. The reference values of B and T cells and their subpopu- lations are very important to understand how the adaptive immune system is responding to infectious agents. The aim of this study was to determine values of B and T cells and their subpopulations in Polish mixed-breed rabbits, considering seasons of the year and sex. The study was performed on 200 Polish mixed-breed rabbits and the percentage of B and T lymphocytes was measured cytometrically using mouse anti-rabbit antibodies. The study revealed that the season of the year and sex of the animals affected the percentage of B- and T-cells and their subpopulations in peripheral blood. Statistically significant values of CD19+ B-cells in spring and autumn, of T CD5+ cells in spring and winter, of T CD4+ in spring, summer, autumn and winter, of T CD8+ in winter and of T CD25+ in spring were noted. Generally the highest values were found mainly in warm part of the year, while the lowest in colder months. A statistical significance was also observed between males and females - changes were found in T CD4+ and T CD25+ lymphocytes in spring, T CD8+ cells in winter and higher percentage was generally obtained in females than in males. The only exception was the T CD5+ subpopulation in which no differences were observed between the sexes and throughout the year. This is the first paper on adaptive immune system cell values in the European rabbit of domestic breeds.

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.

[Blood gas analysis in rabbits during a completely antagonizable anesthesia with special focus on oxygen management]. / Blutgasanalyse beim Kaninchen während einer vollständig antagonisierbaren Anästhesie unter besonderer Berücksichtigung des Sauerstoffmanagements.

OBJECTIVE: The aim of this study was to evaluate the consequences of different oxygen supplementation methods on arterial blood gas analysis during an injectable anesthesia. MATERIAL AND METHODS: A total of 29 rabbits with dental diseases (tooth elongation) were sampled before, during and after coronal reduction. Oxygen was provided either via the flow-by method or with a nasal oxygen tube; the control group breathed room air. RESULTS: All patients receiving oxygen developed respiratory acidosis that intensified during the course of anesthesia. Furthermore, these groups experienced reduced respiratory rates intraoperatively, nevertheless they showed elevated oxygen parameters (hyperoxemia) in the arterial blood gas analysis. No significant differences could be demonstrated between the 2 oxygen providing methods. In the control group, pH remained stable, the oxygen parameters however decreased to less than 80 mmHg (hypoxemia). CONCLUSIONS: Although there were no clinical consequences of hypoxemia or hyperoxemia, moderate oxygen support during an injectable anesthesia is recommended due to the development of hypoxemia. A balance between oxygen supply and oversupply needs to be established to aid in avoiding oxygen toxicity.

Dietary Supplementation with sodium bentonite and coumarin alleviates the toxicity of aflatoxin B1 in rabbits.

Eighty-four male New Zealand White rabbits with average body weight 778 ±â€¯65 g were blocked into four groups to evaluate the ability of sodium bentonite and coumarin in alleviating the toxicity of aflatoxin B1. The first group was fed on a diet without any treatment (CON), while the remaining three diets were added with aflatoxin B1 at 0.25 ppm diet. Diet fed to the third and fourth group of rabbits were further supplemented with sodium bentonite at 5 g/kg (SOB) and coumarin at 5 g/kg (COU) of the diet, respectively. Feeding aflatoxin-contaminated diet (AFL) caused necrosis of liver tissue and reduced the weight gain, average daily gain, feed conversion ratio, nutrient digestibility coefficients, and nitrogen balance of rabbits. This, in turn, was reflected as a reduction in carcass characteristics. The serum collected from rabbits fed aflatoxin-contaminated diet showed decreased levels of total protein, albumin, globulin, glucose, total cholesterol, and triglycerides, and increased concentrations of urea, creatinine, and liver enzymes. Further, aflatoxin diet increased the cecal pH, and decreased the ammonia nitrogen, total volatile fatty acids, and individual fatty acids proportion of cecal fluid. Supplementing sodium bentonite and coumarin at 5 g/kg diet reduced the negative effects of aflatoxin B1 on growth performance, digestibility of nutrients, biochemical parameters, carcass characteristics, and cecal fermentation profile. Furthermore, the coumarin-supplemented group showed better body weight gains and carcass weights compared to the rabbits fed with diets containing sodium bentonite. In conclusion, both sodium bentonite and coumarin supplementation was beneficial in ameliorating the toxicity of aflatoxin B1. Further, the increased body weight gains and better-feed conversion in coumarin-supplemented rabbits project the coumarin as a better anti-aflatoxigenic supplement.

The effects of crossbreeding, age, and sex on erythrocyte indices and biochemical variables in crossbred pet rabbits (Oryctolagus cuniculus).

BACKGROUND: A number of domestic rabbit (Oryctolagus cuniculus) breeds exist, and the pet rabbit population consists of a variety of pure- and crossbred animals. However, the reference intervals (RIs) for rabbits are limited by outdated methods and a single-breed source. OBJECTIVE: This study aimed to establish more complete, updated erythrocytic and biochemical RIs for the crossbred pet rabbit population to improve routine diagnostic accuracy in clinical practice, and to examine the effects of crossbreeding on erythrocytic and biochemical parameters. METHODS: Blood specimens were collected from 85 clinically healthy crossbred pet rabbits representing a wide range of breeds. RIs for the erythrocyte indices and 12 chemistry analytes were determined as recommended by the American Society for Veterinary Clinical Pathology guidelines. The results were compared with four widely used RIs. Age and sex differences for all variables were statistically analyzed. RESULTS: The results diverged from the RIs for New Zealand white rabbits, indicating that not all RIs from this species are appropriate for use in exotic animal practices. Breed-associated variations were evident for aspartate amino transferase, alkaline phosphatase, and glucose, while crossbreed effects were found for total protein, albumin, blood urea nitrogen, creatinine, calcium, and phosphate. Statistically significant differences and clinical relevance among age groups were detected for hemoglobin, hematocrit, and creatinine. CONCLUSIONS: Establishing RIs specifically for crossbred pet rabbits is desirable for clinicians treating pet rabbits of various breeds and ages. Age-specific RIs for this population warrants further investigation.

Diet is a main source of vitamin D in Finnish pet rabbits (Oryctolagus cuniculus).

During the winter time in Finland, sunlight is inadequate for vitamin D synthesis. Many pet rabbits live as house rabbits with limited outdoor access even during summer and may therefore be dependent on dietary sources of vitamin D. The aims of this study were to report the serum 25-hydroxyvitamin D concentrations in Finnish pet rabbits and to identify factors that influence vitamin D status. Serum 25-hydroxyvitamin D concentrations from 140 pet rabbits were determined using a vitamin D enzyme immunoassay (EIA) kit. Eleven rabbits were excluded from the statistical analysis because of unclear dietary data. The remaining 129 rabbits were divided into groups depending on outdoor access during summer (no access n = 26, periodic n = 57, regular n = 46) as well as daily diet: little or no hay and commercial rabbit food ≤1/2 dl (n = 12); a lot of hay and no commercial food daily (n = 23); a lot of hay and commercial food <1 dl (n = 59); a lot of hay and commercial food ≥1 dl (n = 35). The range of serum 25-hydroxyvitamin D concentration was from 4.5 to 67.5 ng/ml with a mean of 26.1 ng/ml. Statistical general linear model adjusted for weight, age and season indicated that diet was associated with vitamin D concentrations (p = 0.001), but outdoor access during summer was not (p = 0.41). Mean 25-hydroxyvitamin D concentration was significantly higher in the rabbits receiving a lot of hay and commercial food ≥1 dl (33.9 ± 13.2 ng/ml) than in rabbits in other diet groups (24.0 ± 8.5 ng/ml, 21.7 ± 8.1 ng/ml, and 22.2 ± 18.0 ng/ml, respectively). This investigation showed wide variation in 25-hydroxyvitamin D concentrations among Finnish pet rabbits. Diet remains a main source since outdoor access seems to be too limited to provide adequate vitamin D synthesis for most of them, and the use of vitamin D supplements is rare.

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.

The effect of subchronic oral exposure to zearalenone on hematologic and biochemical analytes, and the blood redox status of adult rabbit bucks.

BACKGROUND: Zearalenone (ZEN) is a mycoestrogen with a ubiquitous presence in animal feeds, which also has hematotoxic, hepatotoxic, nephrotoxic, and immunotoxic properties. However, there is a paucity of literature that discusses the effects of ZEN on rabbits. OBJECTIVES: The aim of this study was to evaluate the effect of a prolonged, low-level (50 µg ZEN/kg body weight) exposure on the clinicopathologic and redox status analytes of rabbit bucks. METHODS: Ten adult bucks were included in the study. Each underwent a 7-week control period, followed by a 7-week exposure period. Water or ZEN solutions were daily administered orally (0.5 mL) during the control and exposure periods, respectively. Blood samples were collected weekly for Complete Blood Counts, serum biochemical analyte and reactive oxygen metabolite (ROM) measurements. Data were analyzed using a mixed model, and the level of significance was set at a P of <0.05. RESULTS: During the ZEN exposure period, significant increases were noted in the red blood cell distribution width (RDW) and mean platelet volumes (MPVs), as well as in the white blood cell, monocyte, and eosinophil counts. Significant increases were observed in aspartate aminotransferase and total bilirubin, whereas urea, creatinine, glucose, total calcium, sodium, and potassium concentrations were significantly decreased. The ROM concentrations did not differ significantly between the control and ZEN exposure periods. CONCLUSIONS: Under the present experimental conditions, ZEN affected some of the clinicopathologic analytes of adult rabbit bucks; these changes were mostly indicative of mild hepatocellular damage and dysfunction, inflammatory and/or allergic responses, and renal tubular damage. A ZEN dose of 50 µg/kg body weight did not seem to affect the blood redox status of bucks, as evaluated by the ROM concentrations.

Dietary fish oil and flaxseed for rabbit does: fatty acids distribution and Δ6-desaturase enzyme expression of different tissues.

Standard feeds are imbalanced in term of n-6/n-3 polyunsaturated fatty acids (PUFA) ratio, with a low proportion of the latter. The reproductive system appears to be strongly affected by administration of n-3 PUFA, and ingredients rich in α-linolenic acid (ALA; i.e. vegetable sources) or EPA and DHA acids (i.e. fish oil) can be included in animal diets to balance PUFA intake. The aim of this study was to evaluate the effect of dietary supplementation with flaxseed (ALA) or fish oil (EPA and DHA) on PUFA metabolism in rabbit does. A total of 60 New Zealand White female rabbits were assigned to three experimental groups: control group, FLAX group fed 10% extruded flaxseed and FISH group fed 3% fish oil. Blood, milk, liver and ovaries were collected from the does to assess the lipid composition; furthermore, FADS2 gene expression was assessed in liver and ovary tissues. Reproductive performance of does was also recorded. The fertility rate and number of weaned rabbits improved with n-3 dietary supplementation: does at first parity showed the lowest reproductive results, but the administration of n-3 reduced the gap between primiparous and multiparous does. Feed consumption and milk production were not affected by the feeding regime. The fatty acid composition of milk, plasma, liver and ovaries were widely influenced by diet, showing higher concentrations of n-3 long-chain PUFA (LCP) in does fed with n-3 enriched diets. FISH diet resulted in the highest n-3 LCP enrichment, whereas in the FLAX group, this increase was lower. Blood and milk showed low levels of LCP, whereas liver and ovaries were the main sites of n-3 LCP synthesis and accumulation. Accordingly, although the liver is the main metabolic centre for LCP synthesis, ovaries also have a prominent role in LCP generation. FADS2 expression in liver and ovary tissue was downregulated by FISH administration. In conclusion, the enrichment of diets with n-3 PUFA could be an effective strategy for improving the reproductive performance of does.

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.