The role of rabbit meat as functional food

Whole-genome sequencing reveals patterns of runs of homozygosity underlying genetic diversity and selection in domestic rabbits

BACKGROUND

Runs of homozygosity (ROH) are continuous segments of homozygous genotypes inherited from both parental lineages. These segments arise due to the transmission of identical haplotypes. The genome-wide patterns and hotspot regions of ROH provide valuable insights into genetic diversity, demographic history, and selection trends. In this study, we analyzed whole-genome resequencing data from 117 rabbits to identify ROH patterns and inbreeding level across eleven rabbit breeds, including seven Chinese indigenous breeds and four exotic breeds, and to uncover selective signatures based on ROH islands.

RESULTS

We detected a total of 31,429 ROHs across the autosomes of all breeds, with the number of ROHs (NROH) per breed ranging from 1316 to 7476. The mean sum of ROHs length (SROH) per individual was 493.84 Mb, covering approximately 22.79% of the rabbit autosomal genome. The majority of the detected ROHs ranged from 1 to 2 Mb in length, with an average ROH length (LROH) of 1.84 Mb. ROHs longer than 6 Mb constituted only 0.83% of the detected ROHs. The average inbreeding coefficient derived from ROHs (FROH) was 0.23, with FROH values ranging from 0.14 to 0.38 across breeds. Among Chinese indigenous breeds, the Jiuyishan rabbit exhibited the highest values of NROH, SROH, LROH, and FROH, whereas the Fujian Yellow rabbit had the lowest FROH values. In exotic rabbit breeds, the Japanese White rabbit displayed the highest values for NROH, SROH, LROH, and FROH, while the Flemish Giant rabbit had the lowest values for these metrics. Additionally, we identified 17 ROH islands in Chinese indigenous breeds and 22 ROH islands in exotic rabbit breeds, encompassing 124 and 186 genes, respectively. In Chinese indigenous breeds, we identified prominent genes associated with reproduction, including CFAP206, RNF133, CPNE4, ASTE1, and ATP2C1, as well as genes related to adaptation, namely CADPS2, FEZF1, and EPHA7. In contrast, the exotic breeds exhibited a prevalence of genes associated with fat deposition, such as ELOVL3 and NPM3, as well as growth and body weight related genes, including FAM184B, NSMCE2, and TWNK.

CONCLUSIONS

This study enhances our understanding of genetic diversity and selection pressures in domestic rabbits, offering valuable implications for breeding management and conservation strategies.

Comprehensive transcriptome of muscle development in Sichuan white rabbit

BACKGROUND

The Sichuan white rabbit is a unique domestic breed and is famous for its high meat production. Muscle development is a complicated biological process, but the underlying regulatory mechanisms have not been elucidated. Here, we generated comprehensive transcriptome datasets (i.e., mRNAs, miRNAs and lncRNAs) in three developmental stages of Sichuan white rabbits, and aim to systematically explore the regulatory network in myogenesis.

RESULTS

We generated extensive transcriptome datasets (mRNAs, miRNAs and lncRNAs) revealing the myogenic regulatory network at different time points. Our differential expression analysis identified 2,995 DE genes, 1,211 DE-lncRNAs, and 305 DE-miRNAs with distinct expression patterns across developmental stages. In addition, functional enrichment analysis of DE mRNAs and miRNAs indicates their involvement in muscle growth, development, and regeneration, highlighting biological processes and muscle-specific functions. Interaction analysis between DE-lncRNAs and mRNAs uncovered a complex regulatory network, especially between 21 and 27 days of development. These findings contribute to better understanding of the transcriptomic changes during muscle development and have implications for breeding improvement in Sichuan white rabbits.

CONCLUSIONS

Our study provides a comprehensive overview of the transcriptomic changes during muscle development in Sichuan white rabbits. The identification and functional annotation of DE genes, miRNAs, and lncRNAs provide valuable insights into the molecular mechanisms underlying this process. These findings pave the way for targeted investigations into the role of non-coding RNAs in muscle biology.

Effects of vine pepper oil on the deterioration of texture quality in boiled rabbit meatballs: Inhibition of hydrophobic interactions and formation of covalent aggregates

This study explored the influence of Sichuan characteristic vine pepper oil (VPO) on the quality of boiled rabbit meatballs. Sensory analysis revealed that VPO addition alleviated the strong undesirable odor of the meatballs. However, increasing VPO content significantly reduced the texture quality and water-holding capacity (WHC), particularly when VPO exceeded 3 % (v/w). SEM and BET-specific surface area analysis indicated that higher VPO levels promoted globular aggregate formation on the gel surface, increased the number of large pores, and resulted in uneven pore volume distribution. Elevated VPO content reduced the storage modulus and hindered the gel-strengthening phase, and intermolecular force analysis demonstrated significant inhibition of hydrophobic interactions between protein molecules during heating. SDS-PAGE further showed that increased VPO induced covalent bonding between meat proteins and VPO components, forming excessive macromolecular aggregates that disrupted the integrity of the gel structure, ultimately leading to reduced product texture and WHC.

The impact of enriching heat-stressed rabbit diets with flaxseed oil with/ without allicin, lycopene, or Punicalagin on antioxidative status, physiological response and meat omega-3

To improve the health and lifespan of customers, modern nutritionists have focused on improving meat quality and nutritional value. To enhance the unsaturation lipids of rabbit meat, different oil sources used in rabbit diets. Flaxseed oil (FSO) is one way to raise the polyunsaturated omega-3 fatty acid (ω3) in animal meats. On the other hand, FSO can cause high rates of oxidation in rabbit meat under heat stress. Therefore, the use of natural antioxidants may be a good strategy to produce functional meat under stress. The study investigated the beneficial impact of enriching heat stressed rabbit diets with FSO supplemented with/without allicin (ALC), lycopene (LCO) or punicalagin (PCA) during the last 3 weeks before slaughter at a ban temperature ranging from 30 to 35 C, humidity 70 to 82% and temperature humidity index of 27.9 to 31.2 on growth performance, antioxidative status, physiological response, liver and kidney function and ω3 & ω6. In total, 120 male V-line growing rabbits (5 weeks old) were divided into 5 groups, 24 rabbits each. CON rabbits fed a standard diet without supplementation, FO rabbits fed a diet with 1.5% FSO, FOA rabbits fed a diet with 1.5% FSO and 100 mg / kg of ALC diet, FOL rabbits fed a diet with 1.5% FSO with 100 mg LCO / kg of diet, FOP rabbits fed a diet with 1.5% FSO with 100 mg PCA / kg of diet. All treatments with flaxseed oil supplemented with antioxidants significantly elevated ω3 content and ratio between ω3/ω6 of rabbit meat (P ≤ 0.01) while concomitantly reducing total cholesterol without any significant change in physiological response (rectum temperature and respiration rate). Furthermore, these treatments markedly improved antioxidant status, as evidenced by increased total antioxidant capacity and decreased lipid peroxidation. Additionally, serum immunoglobulin G (IgG) significantly (P ≤ 0.01) elevated in FOA, FOL and FOP rabbits compared to the CON group. Supplementation with ALC, LCO and PCA could be recommended to restrain the results of oxidative stress results of enriched diets with ω3 and heat stress to provide healthier and functional rabbit meat (rich in ω3).

Morphometric characteristics of Bambu Apus rabbit

Rabbit meat is a source of protein and is beneficial to health. Bambu Apus rabbits are formed from crosses of several rabbit breeds and have adapted to the environment of DKI Jakarta. The development of rabbits is expected to support an integrated and sustainable urban livestock farming program (sustainable integrated urban farming). The samples used were 65 adult Bambu Apus rabbits and secondary data from 40 adult Rex rabbits and 40 adult New Zealand White rabbits. The observed variables included body weight and morphometrics such as head length, head width, head height, chest circumference, chest width, chest depth, radius ulna length, humerus length, tibia length, femur length, backbone length, hip width, ear length, and ear width. Variance analysis of each variable was carried out through SAS software version 9.4 using PROC GLM procedure, PROC DISCRIM was used for Mahalanobis distance analysis, PROC CANDISC was used for canonical analysis, and MEGA11 software for phenogram tree. The results of discriminant analysis showed that the Bambu Apus rabbit had different morphometric characteristics from the Rex and New Zealand White rabbit. The average weight of Bambu Apus rabbits was 2473.54±480.13 g higher (P<0.05) than Rex rabbit, chest depth 8.69±1.11 cm greater (P<0.05) than Rex and New Zealand White rabbit, backbone length 37.84±3.51 cm longer (P<0.05) than Rex rabbit. Genetic distance and phenogram tree construction showed low kinship relationship between Bambu Apus rabbit with Rex rabbits and New Zealand White rabbit. The results suggested that the genetic of Bambu Apus rabbit has a predisposed to be produced as tropical climate adapted broiler rabbits.

Effect of Selection for Litter Size Variability on Growth, Carcass and Meat Quality in Rabbits

This study aimed to analyze the effect of reducing litter size variability on growth rate, carcass traits, and meat quality in rabbits. Two divergent lines selected by litter size variability were compared: a line selected to reduce litter size variability (HO) and one selected to increase litter size variability (HE). All animals were fed the same commercial diet and kept under identical rearing conditions. The HO line had lower live weight at weaning compared to the HE line (p ≤ 0.05), but the growth rate was higher in the HO line than in the HE line (p ≤ 0.05). Carcass weight and composition were similar between the lines. No differences in meat pH at 45 min and 24 h post-mortem were found between lines. However, the HO line had a higher lightness (L*) value at 45 min post-mortem than the HE line (p ≤ 0.05). The HO line showed higher Ca concentrations than the HE line (p ≤ 0.05). The HO line also had higher protein content and lower saturated fatty acid content than the HE line (p ≤ 0.05). No differences in fat oxidation were observed among the lines. In conclusion, the selection to reduce litter size variability did not negatively impact growth rate and had a favorable effect on protein content, as well as a reduction in saturated fatty acid content in carcass.

The Use of Grape By-Products as a Feed Additive Enhances the Oxidative Stability of Rabbit Meat

The use of agro-industrial by-products in livestock nutrition is of increased interest to the feed industry. Some of the by-products are rich in bioactive compounds that could lead to an increase in the quality of animal meat products. This study aimed to evaluate the effects of dietary incorporation of grape pomace (GP), a by-product rich in polyphenols, on growth and on the oxidation status and the fatty acid profile of rabbit meat. Forty-eight male rabbits (Oryctolagus cuniculus) (aged 55 ± 3 d and ca 2.3 kg) divided into three groups of 16 were used in the trial. The rabbits were housed in pairs in wire-mesh cages (26 × 46 × 35 cm) giving n = 8 for each diet treatment. The first group was fed a basal diet (CTR) (ca 18% protein and ca 4% fat), the second was given a basal diet supplemented with 5 g GP per head per day (low-GP) and the third group was fed a basal diet supplemented with 10 g GP per head per day (high-GP). The trial lasted three weeks, and the animals were weighed weekly. The rabbits were slaughtered, and the weight and the pH of the carcasses was measured immediately after slaughter and after 24 h of cooling at 4 °C. The pH of the stomach and cecum was measured. A sample of Longissimus Dorsi (LD) was collected and stored at -80 °C for the analysis of proximate composition, thiobarbituric acid reactive substances (TBARs) and fatty acid profile (FA). The diet did not influence the growth or the pH of the stomach and cecum of the rabbits. The chemical composition of the meat was similar in all groups, with a mean protein of 22.3% and fat of 0.95%. The fatty acid profiles of the LD were not influenced by the diet, and the most abundant FAs were C16:0, C18:2n6 and C18:1c9. Feeding GP to the rabbits gave a linear decrease of TBARs in the meat, indicating a reduction in oxidative stress. The TBARs' reduction was 60% in the meat of the rabbits given high-GP compared to CTR. In conclusion, GP could be used in rabbit diets without any negative influence on meat quality but with an increase in oxidation stability that could enhance meat shelf-life.

Global prevalence of lagomorpha coccidiosis from 1951 to 2024: A systematic review and meta-analysis

The global prevalence of coccidia infection in lagomorphs and potential risk factors were investigated through a meta-analysis of 149 studies published between 1951 and 2024. The pooled prevalence of Eimeriidae, Sarcocystidae and Cryptosporidiidae was found to be 66.0 %, 8.0 % and 6.1 %, respectively. Rabbits and hares exhibited the highest prevalence of Eimeriidae at 63.1 % and 71.8 %, while pikas had the highest prevalence of Cryptosporidiidae at 17.1 %. Countries located in the southern hemisphere exhibited the highest prevalence of Cryptosporidiidae (11.4 %). The African Region had the highest prevalence of Eimeriidae (73.3 %) and Sarcocystidae(14.6 %), while the Eastern Mediterranean Region had the highest prevalence of Cryptosporidiidae(13.6 %). Juvenile rabbits exhibited the highest prevalence of Eimeriidae (67.4 %), while senior Rabbit exhibited the highest prevalence of Sarcocystidae(17.1 %) and Cryptosporidiidae(13.1 %). The prevalence of coccidia in intensively farmed lagomorphs showed a slight upward trend over time, nearly reaching statistical significance (R2 = 7.88 %, coefficient = 0.019, P = 0.127). This suggests that the current intensive farming practices may be losing effectiveness in controlling coccidia infections, which is concerning. Among Eimeriidae in lagomorphs, Eimeria coquelinae showed the highest prevalence (68.4 %), while E. magna was most frequently reported. For Sarcocystidae, Besnoitia spp. had the highest prevalence (31.3 %), with Toxoplasma gondii being most frequently reported. Cryptosporidium cuniculus was both the most prevalent and frequently reported Cryptosporidiidae species (6.9 %), suggesting it may be a major Cryptosporidiidae pathogen in lagomorphs. These findings highlight the differences in prevalence of various Eimeriida species among different lagomorpha genera. This diversity underscores the complex relationships between specific parasites and their host species, contributing to a more nuanced understanding of coccidiosis epidemiology in lagomorphs worldwide.

Quality and Microbial Changes in Omega-3-Enriched Rabbit Meat Packaged with an Active Absorbent Pad in MAP

This study evaluated the efficacy of an active absorbent pad (aPAD) in reducing microbial growth and enhancing the shelf life of rabbit meat stored in modified atmosphere packaging (MAP). Thigh muscles from 60 rabbits were used, divided into three dietary groups: a control group (CNT), a group supplemented with 5% extruded flaxseed (ELS5%), and a group with 3.5% extruded flaxseed and 0.2% Padina pavonica algae (LPP3.5%). Samples were packaged in MAP (70% O2, 30% CO2) with either a conventional pad (nPAD) or aPAD and analyzed at 1, 4, 7, 14, 21 days. Microbiological analysis revealed a significantly lower total viable count at 21 days in the ELS5%aPAD group. For coagulase-positive staphylococci, the CNTaPAD group showed lower microbial counts at both day 4 and day 21 (p < 0.05). Enterobacteriaceae reductions were observed at 24 h post packaging in both the CNTaPAD and LPP3.5%aPAD groups and at day 14 in ELS5%aPAD. Lipid oxidation (TBARS) was also lower in aPAD samples, particularly in LPP3.5%, which remained below 1.5 mg MDA/kg compared to >2.5 mg MDA/kg in nPAD (p < 0.05). Sensory attributes such as texture and color were better preserved with aPAD. These findings underscore the effectiveness of aPAD in MAP to control microbial growth, limit oxidation, and extend the shelf life of omega-3-enriched rabbit meat, providing a promising solution for functional meat product preservation.

The Fatty Acid Content, Health Lipid Indices, and Instrumental, Histological, and Sensory Quality of Hare Meat (Lepus europaeus Pallas)

The aim of this work was to characterize the quality of meat from hares (Lepus europaeus Pallas), namely, the fatty acid content, health lipid indices, and instrumental, histological, and sensory profiles by gender and muscle type (Longissimus dorsi/LD vs. Semimembranosus/SM). The ΣPUFA/Σ SFA was higher for males, with an average value of 1.62/1. The Σn6/n3 ratio was elevated for males, with a mean value of 5.34/1. The mean meat essential fatty acids were 41.94%, the desirable fatty acids were 77%, and the polyunsaturation index was 6.09. Moreover, the atherogenic index was 0.72, the thrombogenic index was 0.71, the hypocholesterolemic/hypercholesterolemic (h/H) fatty acids ratio was 3.30, and the nutritive value index was 1.35. After the sensory analysis, the LD muscles showed higher scores in males for overall appreciation (4.20 vs. 3.95) but higher scores in females for SM muscles (4.14 vs. 4.00). Shear force was influenced by the ratio between muscle and connective tissue, and the proportion of collagen and protein was related to the number of muscle fibers. Muscle and connective tissues are inversely proportional, and their ratio is an indicator of the textural and mechanical properties of the analyzed samples. Hare meat is an appreciated resource for consumers in terms of its sensory, instrumental, and nutritional values, and it has a higher value than that obtained from livestock species or other wild animals (more valuable proteins, lower fat content, and better health lipid indices).

Effects of Diets Containing Extruded Linseed and Padina pavonica Algae on Meat Rabbit: Carcass Performance and Meat Quality

This study investigated the effects of dietary supplementation with extruded linseed (ELS) and Padina pavonica algae extract (PP) on rabbit carcass and meat quality. Ninety-six rabbit carcasses from two production cycles were analyzed. In the first cycle (C1), rabbits were fed a control diet (1CNT), the same diet supplemented with 5% ELS (1ELS5%), and supplemented with 3.5% ELS and 0.2% PP (1LPP3.5%). In the second cycle (C2), the diets varied in composition and supplementation levels: a different control diet (2CNT), the same diet with 5% ELS (2ELS5%), and with 5% ELS and 0.2% PP (2LPP5%). Meat analyses were performed on Longissimus thoracis et lumborum (LTL) muscle for physical properties and on thigh meat (THM) for proximate composition, vitamin E, coenzyme-Q10, cholesterol, fatty acid profile, and mineral content. No significant differences in LTL physical quality were observed in C1, although LTL was brighter in C2 (p < 0.001). THM in C2 had higher fat content (p < 0.001). Dietary supplementation with ELS and PP extract significantly increased polyunsaturated fatty acids (n-3 PUFAs) and improved the n-6/n-3 ratio (p < 0.001) in rabbit meat, demonstrating their positive impact on meat quality.

Improving quality and consumer acceptance of rabbit meat: Prospects and challenges

Rabbit meat is an excellent source of high-quality proteins, essential fatty acids, vitamins, and minerals, which can be further improved through various management, preslaughter, and post-slaughter interventions. Rabbit meat consumption is popular in certain regions of the world. The multidimensional role of rabbits as pet, pest, and laboratory animals, lack of proper knowledge among consumers towards the nutritive value of rabbit meat, animal welfare, and ethical issues, sustainable potential, undeveloped marketing, and processing chain, and price parity with available cheap meat and non-meat alternatives, are some constraints in the rabbit meat production. Increasing awareness of the nutritive value, positive health effects of rabbit meat consumption and production chain, development of processed meat products, and proper animal welfare compliance in rabbit production could improve consumer acceptance. The present manuscript reviewed various factors that affect the meat quality and consumer acceptance of rabbit meat for a more sustainable and viable source for global meat supply.

Threonine attenuates lipopolysaccharide-induced intestinal inflammatory responses in rabbits

PURPOSE

Threonine (Thr) can be involved in the synthesis of immunoglobulins, which play the role of immune regulation, Thr also has to improve intestinal morphology, adjust the sticky protein synthesis, maintain the intestinal barrier function, etc. The experiment aimed to investigate the effects of diets supplemented with different levels of Thr on growth performance and intestinal health of rabbits under lipopolysaccharide (LPS) stress conditions.

METHODS

A total of 180 healthy 35-day-old weaned New Zealand White rabbits were randomly assigned in a 2 × 3 factorial design to receive an intraperitoneal injection of 100 µg/kg BW LPS or saline and three diets with different levels of digestible threonine (0.43%, 0.54%, and 0.64%).

RESULTS

The LPS challenge resulted in a reduction in body weight in rabbits at day 22, as well as a decrease in the serum d-lactic acid (D-LA) content and the number of goblet cells (GCs) in the jejunum. Additionally, the duodenum JAM2 and JAM3 were down-regulated. The expression of OCLN, ZO-1, and IL-2 in the jejunum, and CLDN, nuclear factor-κB (NF-κB) and ZO-1 mRNA in the ileum were also down-regulated. Furthermore, the duodenum TLR4 and IL-1β mRNA expression, while the jejunum exhibited an elevation in CLDN, TNF-α, and ileum TNF-α mRNA expression (P < 0.05). In the context of LPS challenge condition, dietary Thr addition was found to down-regulate the duodenum ZO-1 and jejunum CLDN mRNA expression of rabbits (P < 0.05). This was accompanied by an increase in ileum sIgA content and GCs number (P < 0.05). Additionally, dietary Thr addition resulted in a downregulation of duodenum TLR4, MyD88, NF-κB, TNF-α and IL-1β, jejunum MyD88, and IL-1β mRNA expression, as well as an up-regulation of ileum IL-10 mRNA expression in rabbits (P < 0.05).

CONCLUSION

In conclusion, the LPS challenge can result in intestinal inflammation and damage the integrity of the intestinal barrier in rabbits. Nevertheless, dietary Thr supplementation can alleviate the intestinal inflammatory response in rabbits challenged with LPS.

Grape Pomace for Feed Enrichment to Improve the Quality of Animal-Based Foods

In this review, the potential role of grape pomace (GP) as a tool for improving feed has been critically summarized, considering the findings of the literature of the last five years (2020-2024). The main applications of GP to the nutrition of different animals and the impact on derived foods (meat, milk and dairy products, eggs, fish) are discussed along with the major advantages and limits. Emphasis was placed on the phenols and fatty acids of GP, which are considered phytochemicals with health-promoting effects. Phenolic compounds increase the antioxidant potential of animal-based foods even if their content and profile are strongly related to grape cultivar and geographical origin. Unsaturated fatty acids, including linoleic and oleic acids, contributed to extending the shelf life of new products. Few approaches exploited chemometrics tools. Generally, GP showed a promising role in feed fortification, even if, in most cases, GP was key only if used in a correct percentage within a balanced diet and for an adequate administration time. From a multidisciplinary perspective, future research endeavors should prioritize a larger sampling, a deep phenol fraction characterization, and an appropriate chemometric approach.

Effect of dried cauliflower leaf meal (Brassica oleracea var botrytis) dietary supplementation on the growth performance, carcass and meat characteristics of rabbits

The purpose of this study is to investigate the effect of feeding cauliflower leaf meal (CLM) on growth performance, nutrient utilization, carcass characteristics, histopathology and economics of rabbit production. A total of eighteen 45-day-old Newzeland White rabbits were randomly divided into three groups and fed with control (0%), 20% and 30% CLM in concentrate mixture and feeding trial continued for 3 months. Growth performance was recorded upto the end of the trial. On completion of the growth study, a digestibility trial was conducted to assess the digestibility of nutrients. Afterwards, all the experimental rabbits were slaughtered to evaluate the carcass and meat quality, and to examine histological changes in the viscera. The cost of production was calculated on the basis of partially replacing wheat bran with CLM. Results showed that the body weight gain, feed intake, feed conversion ratio and digestibility of nutrients were similar among the groups of rabbits. Further, dressing percentage, wholesome cut yield, chemical composition of meat, sensory evaluation, water holding capacity and shear force value were also comparable among all groups. However, total phenolic content, vitamin A and E, and polyunsaturated fatty acid were significantly (p < 0.05) higher and 2-Thiobarbituric acid reactive substance was significantly (p < 0.05) lower in 30% CLM-fed group. Histopathological study showed no pathological changes in viscera of rabbits fed with CLM. Moreover, the cost of production was significantly (p < 0.05) lower in 30% CLM-fed group of rabbits. The present work shows that the 30% CLM can be incorporated in concentrate mixture in rabbit diet without affecting growth performance or meat quality and successfully used in rabbit nutrition, which will be cheaper with enhanced keeping quality of meat.

Hepatitis E virus in wild and domestic rabbits from Portugal: a combined molecular and longitudinal serological study

Hepatitis E virus (HEV), species Paslahepevirus balayani, poses a global public health threat, especially in developing countries, by causing acute enterically transmitted hepatitis. HEV infects various mammalian hosts and belongs to the genus Paslahepevirus in the family Hepeviridae. While swine are recognized as the main hosts of HEV, rabbits, which can also be affected by swine HEV-3 related strains, serve as the primary reservoir for the distinct emerging and zoonotic HEV-3ra subtype. In Portugal, where the European wild rabbit is abundant, their role in HEV epidemiology remains unclear. The primary aim of the present research was to evaluate the circulation and the potential for HEV infection within these species. This study employed a molecular and longitudinal serological approach to investigate HEV in Portuguese rabbits. Among the 205 wild rabbits tested, a seroprevalence of 2.44% (95% CI: 0.80-5.60) was found, with no significant associations with age, sex, localization, or sampling dates. Seropositive animals were found in the south and center regions of the country. HEV RNA was not detected in 120 fecal samples, suggesting a natural, low level, and widespread viral circulation. The study underscores the need for further research to comprehend HEV dynamics in these species, which is crucial for assessing potential transmission risks to humans.

Enhancing the Shelf Life of Sous-Vide Red Deer Meat with Piper nigrum Essential Oil: A Study on Antimicrobial Efficacy against Listeria monocytogenes

Using sous-vide technology in combination with essential oils offers the potential to extend the preservation of food items while preserving their original quality. This method aligns with the growing consumer demand for safer and healthier food production practices. This study aimed to assess the suitability of minimal processing of game meat and the effectiveness of vacuum packaging in combination with Piper nigrum essential oil (PNEO) treatment to preserve red deer meat samples inoculated with Listeria monocytogenes. Microbial analyses, including total viable count (TVC) for 48 h at 30 °C, coliform bacteria (CB) for 24 h at 37 °C, and L. monocytogenes count for 24 h at 37 °C, were conducted. The cooking temperature of the sous-vide was from 50 to 65 °C and the cooking time from 5 to 20 min. Additionally, the study monitored the representation of microorganism species identified through mass spectrometry. The microbiological quality of red deer meat processed using the sous-vide method was monitored over 14 days of storage at 4 °C. The results indicated that the TVC, CB, and L. monocytogenes counts decreased with the temperature and processing time of the sous-vide method. The lowest counts of individual microorganism groups were observed in samples treated with 1% PNEO. The analysis revealed that PNEO, in combination with the sous-vide method, effectively reduced L. monocytogenes counts and extended the shelf life of red deer meat. Kocuria salsicia, Pseudomonas taetrolens, and Pseudomonas fragi were the most frequently isolated microorganism species during the 14-day period of red deer meat storage prepared using the sous-vide method.

Influence of Long-Term Freezing of Carcasses in Pre- and Post-Rigor Mortis Stages on the Technological and Nutritional Parameters of the Longissimus lumborum Muscle of Botucatu Rabbits

The aim was to assess the impact of long-term storage on the quality of Botucatu rabbit meat frozen in pre- and post-rigor stages. The stability of the technological and nutritional parameters of Longissimus lumborum (LL) muscle was analyzed over 12 months. In the post-rigor phase, the dorsal LL surface showed a higher level (p < 0.05) of redness and saturation, while the ventral surface showed a higher level (p < 0.05) of yellowness compared to the pre-rigor LL muscle. During storage, the redness and saturation in the LL muscle decreased (p < 0.05), while the yellowness increased (p < 0.05) on both dorsal and ventral surfaces. In the first six months, the pre-rigor meat had a higher pH (p < 0.05) compared to the post-rigor meat. The fresh meat showed higher (p < 0.05) shear force values in the post-rigor stage. Over the 12-month study period, the lipid oxidation, myofibrillar fragmentation index, gross energy, and levels of protein, fat, and carbohydrates increased (p < 0.05), while the shear force, mineral content, and moisture decreased (p < 0.05). Thus, rigor mortis affects meat color in Botucatu rabbits. Fresh meat in the pre-rigor stage is softer, moister, and less acidic than post-rigor meat after 24 h of chilling. Long-term freezing enhances tenderness, regardless of the rigor phase at freezing, preserving its physical, chemical, and nutritional quality, with minor changes in color, lipid oxidation, and chemical composition.

Genome-Wide Association Studies of Growth Trait Heterosis in Crossbred Meat Rabbits

The application of heterosis can not only effectively improve the disease resistance and meat quality of livestock, but also significantly enhance the reproduction and growth of livestock and poultry. We conducted genome-wide association studies using data from F2 crossbred meat rabbits to screen out candidate genes with significant dominant effects associated with economic trait variation. High-throughput sequencing technology was used to obtain SNPs covering the whole genome to evaluate the homozygosity of the population genome, and analyze the number, length, frequency, and distribution of ROHs in the population. Candidate genes related to economic traits of meat rabbits were searched based on high-frequency ROH regions. After quality control filtering of genotype data, 380 F2 crossbred rabbits were identified with 78,579 SNPs and 42,018 ROHs on the autosomes. The fitting of the Logistic growth curve model showed that 49-day-old rabbits were a growth inflection point. Then, through genome-wide association studies, 10 SNP loci and seven growth trait candidate genes were found to be significantly related to body weight in meat rabbits at 84 days of age. In addition, we revealed the functional roles and locations of 20 candidate genes in the high-frequency ROH region associated with economic traits in meat rabbits. This study identified potential genes associated with growth and development in the high-frequency ROH region of meat rabbits. In this study, the identified candidate genes can be used as molecular markers for assisted selection in meat rabbits. At the same time, the inbreeding situation based on ROH assessment can provide reference for breeding and breeding preservation of meat rabbits.

Dietary effect of Dendrobium officinale leaves on chicken meat quality, fatty acid composition, and volatile compounds profile

Dendrobium officinale leaves (DOL) contain many active ingredients with various pharmacological effects, but are still ineffectively utilized. To investigate the feasibility of developing DOL as a feed additive, it is necessary to determine whether dietary supplementing DOL had any effect on meat quality and flavor. Our results showed that supplementation with DOL decreased the shear force while increased the pH and fat content in breast meat. Meat from DOL-fed chickens had higher levels of n-3 polyunsaturated fatty acids (PUFAs) and n-6 PUFAs, but lower n-6/n-3 ratios. Moreover, volatile compounds profile indicated that contents of aldehydes, including hexanal, pentanal, and heptanal, etc.), which were identified as the key volatile compounds in chicken meat, exhibited noteworthy rise in DOL intake groups. Octanal, 1-octen-3-ol, and 2-pentylfuran also contributed greatly to the meat overall aroma. These data provide a foundation for the comprehensive utilization of DOL as a feed additive with antibiotic substitution potential.

Elements in Serum, Muscle, Liver, and Kidney of Rabbits Fed Macroalgae-Supplemented Diets

The addition of marine macroalgae to animal feed has garnered interest due to the demonstrated benefits of gut health in many livestock species. Most macroalgae have a higher mineral content than terrestrial vegetables, making them an attractive, sustainable source of minerals. However, some macroalgae contain elevated concentrations of iodine and arsenic, which may be transferred to the meat of livestock fed with macroalgae. This study evaluated the mineral profile of rabbit serum, muscle, liver, and kidney of rabbits fed diets supplemented with different marine macroalgae, with the goal of improving post-weaning gut health and reducing reliance on antibiotics. We found increased deposition of iodine in muscle, liver, and kidney due to macroalgae supplementation, which is particularly promising for regions with low iodine endemicity. Higher, though relatively low arsenic concentrations, compared to those in other animal meats and food sources, were also detected in the muscle, liver, and kidney of macroalgae-fed rabbits. The absence of apparent interactions with other micronutrients, particularly selenium, suggests that the inclusion of macroalgae in rabbit diets will not affect the overall mineral content. Enhanced bioavailability of elements such as phosphorus and iron may provide additional benefits, potentially reducing the need for mineral supplementation.

Effects of chitosan-based packaging film crosslinked with nanoencapsulated star anise essential oil and superchilled storage on the quality of rabbit meat patties

In this paper, the effects of chitosan film containing star anise essential oil nanofiltration (CFSAO) and superchilled (SC) temperature on the changes of physicochemical and microbiological indexes of rabbit meat patties within 15 days of storage were studied. The total aerobic bacteria counts, malondialdehyde content, protein carbonyl content, total sulfhydryl content, and metmyoglobin content continued to grow throughout the entire experimental period, and the maximum absorption peak at the soret region of myoglobin gradually decreased. Along with the storage time extended, the brightness and redness of rabbit meat significantly decreased (P < 0.05), while the yellowness significantly increased (P < 0.05). The results of storage experiments showed that chitosan composite films and SC temperature had good inhibition on lipid oxidation, myoglobin oxidation and degradation, sulfhydryl content reduction, and microbial growth of rabbit meat after 15 days of storage, and could slow down the change of rabbit meat color.

Application of Autochthonous Biofilm-Forming Enterococcus hirae Kr8 Strain in Relation with Enterocin M in Broiler Rabbits and Their Effect on the Rabbit Meat Quality: Risk or Protection?

Around weaning, rabbits are sensitive to gastrointestinal diseases, mostly of bacterial origin, including enterococci (Enterococcus hirae), clostridia, and coliforms. Preventive use of postbiotics-enterocins-as feed additives can reduce this problem. Therefore, simulation of spoilage/pathogenic environment applying the autochthonous, biofilm-forming E. hirae Kr8+ strain in rabbits and its influence on rabbit meat quality as well as the protective effect of Ent M on rabbit meat properties and quality in infected animals was tested. Ninety-six rabbits aged 35 days, both sexes, meat line M91 breed were divided into one control (CG) and three experimental (EG1, EG2, and EG3) groups. The rabbits in CG received standard diet, without any additives, rabbits in EG1 received 108 CFU/mL of Kr8+ strain (at a dose of 500 μL/animal/day), to rabbits in EG2 the Ent M (50 μL/animal/day), and in EG3, combination of the Kr8+ and Ent M was applied in their drinking water during 21 days. The experiment lasted 42 days. The Kr8+ strain did not attack the gastrointestinal tract and have any adverse effect on the meat quality of rabbits. Moreover, improved weight gains, carcass parameters, and higher essential fatty acid (EAA) and amino acid (EAA) content of rabbit meat point rather to its possible beneficial potential in rabbit nutrition. Administration of Ent M improved most of the tested parameters: animal weight and meat physicochemical and nutritional properties, with a focus on EFA and EAA. During combination of both additives, their synergistic impact was noted, improving the nutritional quality, mostly the EAA content of rabbit meat.

Social, ethical, environmental, economic and technological aspects of rabbit meat production - A critical review

Rabbit (RM) has become a valuable source of nutrients since the 1970s, helping to transform the European food industry into the largest RM producer in the world. However, the RM industry is experiencing a critical period of ethical imbalance. This trend, described as feed conversion ratio, impacts the environmental and financial performance of RM farms, which could lead to an increase production of industrial waste. In addition, the loss of corporate ethical responsibility and sustainable development by RM-oriented companies has further exacerbated the situation. Our objective was to summarize current trends in the RM industry and markets, highlighting possible strengths and weaknesses. This review shows current approaches in sustainable techniques in RM production processes, ethical issue, environmental and processing responsibility of RM producers, as well as social responsibilities and ethical practices of slaughterhouses and RM producers, sustainable environmental practices of slaughterhouses, technological aspects and safety of RM and social drivers in RM market. The analysis of reviewed literature revealed the potential strategies for sustainable RM production.

Absolute quantification of targeted rabbit liver- and meat tissue-specific peptide markers in highly processed food products

A highly sensitive and selective method for the simultaneous absolute quantification of peptides unique to rabbit meat- and liver-specific tissue was developed using liquid chromatography - triple quadrupole mass spectrometry. Two rabbit skeletal muscle-specific peptides (SSVFVADPK and PHSHPALTPEQK), three rabbit liver tissue-specific peptides (FNLEALVTHTLPFEK, AILNYVANK, and TELAEPTSTR) and one peptide specific to both rabbit offal and skeletal muscle tissue (AFFGHYLYEVAR) were monitored. Analyses were performed using peptides labelled with stable isotopes (13C and 15N) as internal standards. Fifteen food samples containing rabbit meat and/or liver were analysed to verify compliance of the rabbit meat and liver composition with product labelling. One sample was adulterated with undeclared rabbit liver. The limit of detection and limit of quantification for the selected peptides of interest were in the range of 0.17 to 0.35 ng/mg and 0.57 to 1.17 ng/mg, respectively. The method may be useful for the determination of rabbit meat and liver tissue in highly processed food samples.

Anti-Salmonella Activity of Thymus serpyllum Essential Oil in Sous Vide Cook-Chill Rabbit Meat

Food is generally prepared and vacuum-sealed in a water bath, then heated to a precise temperature and circulated in a sous vide machine. Due to its affordability and ease of use, this cooking method is becoming increasingly popular in homes and food service businesses. However, suggestions from manufacturers and chefs for long-term, low-temperature sous vide cooking raise questions about food safety in the media. In this study, heat treatment with different times and wild thyme essential oil (EO) in sous vide-processed rabbit longissimus dorsi muscle were found to inactivate Salmonella enterica. The rabbit meat samples were vacuum-packed in control groups, in the second group the rabbit meat samples were injected with S. enterica, and in the third group were meat samples infected with S. enterica with Thymus serpylum EO additive. The vacuum-packed samples were cooked sous vide for the prescribed time at 55, 60, and 65 °C. At 5, 15, 30, and 60 min, the quantities of S. enterica, total bacterial counts, and coliform bacteria were measured in groups of sous vide rabbit meat. Microbiological analyses of rabbit meat samples on days 1 and 7 were evaluated. In this study, total viable counts, coliforms bacteria, and number of Salmonella spp. were identified. After incubation, isolates from different groups of microorganisms were identified by the mass spectrometry technique. For each day measured, the test group exposed to a temperature of 55 °C for 5 min had a greater number of total microbiota. The most isolated microorganisms by MALDI-TOF MS Biotyper from the control and treated groups were Lactococcus garvieae and in the treated groups also S. enterica. Based on our analysis of sous vide rabbit meat samples, we discovered that adding 1% of thyme essential oil to the mixture reduced the amount of Salmonella cells and increased the overall and coliform bacterial counts. The microbiological quality of sous vide rabbit meat that was kept for seven days was positively impacted by the addition of thyme essential oil.

Effects of betaine on growth performance and intestinal health of rabbits fed different digestible energy diets

An experiment was conducted to determine the effects of betaine on growth performance and intestinal health in rabbits fed diets with different levels of digestible energy. During a 36-d experiment, a total of 144 healthy 35-d-old weaned New Zealand white rabbits with a similar initial body weight (771.05 ± 41.79 g) were randomly distributed to a 2 × 3 factorial arrangement. Experimental treatments consisted of two levels of digestible energy (normal: 10.20 and low: 9.60 MJ/kg) and three levels of betaine (0, 500, and 1,000 mg/kg). Results indicated that rabbits fed the diet with low digestible energy (LDE) had reduced body gain/feed intake on days 1 to 14 and 1 to 36 (P < 0.05), increased the apparent total tract digestibility (ATTD) of neutral detergent fiber, acid detergent fiber (ADF), and n-free extract, and decreased the ATTD of gross energy (GE), crude fiber, and organic matter (OM; P < 0.05). The LDE diet upregulated the gene abundance levels of duodenum junctional adhesion molecule-3 (JAM-3) and downregulated the ileum toll-like receptor 4, myeloid differentiation factor 88, and interleukin-6 (IL-6; P < 0.05). Activities of amylase, lipase, trypsin, and the immunoglobulin M content in the jejunum were decreased in the LDE treatment group (P < 0.05). Dietary betaine supplementation increased the ATTD of GE, dry matter (DM), ADF, and n-free extract by LDE (P < 0.05). The villus height, crypt depth, and goblet cell numbers were decreased, and the villus-crypt ratio was increased in the duodenum (P < 0.05). The gene abundance levels of duodenum IL-2 were downregulated, and the duodenum JAM-2 and JAM-3 were upregulated (P < 0.05). Furthermore, the addition of betaine to the LDE diet increased the ATTD of GE, DM, and OM in rabbits (P < 0.05). Gene abundance levels of ileum IL-6 and duodenum JAM-3 were upregulated (P < 0.05). In summary, LDE diets can reduce the activity of intestinal digestive enzymes and decrease the ATTD of nutrients. However, the addition of betaine to LDE diets improved the intestinal barrier structure and nutrient ATTD in rabbits, with better results when betaine was added at an additive level of 500 mg/kg.

New insights in improving sustainability in meat production: opportunities and challenges

Treating livestock as senseless production machines has led to rampant depletion of natural resources, enhanced greenhouse gas emissions, gross animal welfare violations, and other ethical issues. It has essentially instigated constant scrutiny of conventional meat production by various experts and scientists. Sustainably in the meat sector is a big challenge which requires a multifaced and holistic approach. Novel tools like digitalization of the farming system and livestock market, precision livestock farming, application of remote sensing and artificial intelligence to manage production and environmental impact/GHG emission, can help in attaining sustainability in this sector. Further, improving nutrient use efficiency and recycling in feed and animal production through integration with agroecology and industrial ecology, improving individual animal and herd health by ensuring proper biosecurity measures and selective breeding, and welfare by mitigating animal stress during production are also key elements in achieving sustainability in meat production. In addition, sustainability bears a direct relationship with various social dimensions of meat production efficiency such as non-market attributes, balance between demand and consumption, market and policy failures. The present review critically examines the various aspects that significantly impact the efficiency and sustainability of meat production.

Dietary Supplementation with Pithecellobium dulce (Roxb) Benth Fruits to Fattening Rabbits

Pithecellobium dulce produces a fruit used in alternative medicine that could be utilized to feed rabbits. The objective of this study was to measure the effect of the P. dulce fruit on productive performance, carcass traits, meat characteristics, and meat product quality as well as shelf-life. Seventy-two California × English pot crossbreed rabbits (35 d age) were randomly distributed into two treatments: a control group without P. dulce and another group fed with 5% of P. dulce, and fattening for 28 d. Productive performance parameters, blood biochemistry and hematology, apparent digestibility, carcass traits, meat characteristics, and meat product shelf-life were measured. The results indicate inclusion of 5% P. dulce improves (p < 0.05) dry and organic matter digestibility and feed conversion rate, but some serum blood enzymes were increased (p < 0.05). The a* value, hardness, and pH decreased (p < 0.05) in the group fed with P. dulce. Antioxidant properties in the meatballs were different (p < 0.05), improving shelf-life and acceptance in sensory analysis. In conclusion, the use of 0.5% of P. dulce fruits to feed fattening rabbits can be used to improve the shelf-life of rabbit meat.

Potential and limitations of rabbit meat in maintaining food security in Ukraine

The aim of the present review was to assess whether rabbit meat production can help to improve food security in Ukraine and whether it can make a meaningful contribution to the national economy. Rabbit meat is a nutrient-rich and affordable food with a lower environmental impact than red meat from cattle or sheep. Rabbit meat is considered healthy, as it is lower in fat, cholesterol and sodium than other types of meat, and rich in protein. In addition, rabbit meat proteins can serve as a source of bioactive peptides with the angiotensin converting enzyme (ACE) inhibition properties. The health-promoting properties of rabbit meat and role of associated by-products in providing nutritious and safe food for consumers, and in reducing waste in the meat sector, should be promoted. In Ukraine, rabbit meat products are already recommended as part of a healthy diet for children, pregnant women and the elderly, and the market could be broadened by introducing more rabbit-based products for the whole population. Rabbit production in Ukraine is a promising area of economic activity and with a broader market this segment could increase further and become a significant part of the economy. However, the rabbit farming sector in Ukraine needs comprehensive improvement to address existing issues, including the introduction of sustainable production methods in accordance with European animal welfare and meat quality standards.

Ramifications of Heat Stress on Rabbit Production and Role of Nutraceuticals in Alleviating Its Negative Impacts: An Updated Review

Heat stress has become a widespread concern worldwide, which is a major environmental stress that causes substantial economic loss in the rabbit industry. Compared to other agricultural animals, rabbits are more sensitive to heat stress as they have fewer sweat glands and a thicker coat of fur, increasing the heat dissipation complexity. Thus, heat stress hurts rabbits' productivity, meat quality, reproductive performance, antioxidative properties, immune responsiveness, intestinal histomorphology, and microbiome. Nutraceuticals include vitamins, minerals, antioxidants, organic acids, fatty acids, probiotics, prebiotics, synbiotics, enzymes, and medicinal plants due to the possible impacts on maintaining common biological situations, strengthening immune response, and preventing illness, which ultimately led to an increase in productivity. Nutraceuticals have recently attracted a lot of attention to alleviate the adverse impacts of heat stress in rabbit farms. The objective of the current review is to provide acquaintance with the recent findings about the impact of heat stress on rabbit productivity and the advantages of dietary supplementation of nutraceuticals in mitigating it.

Insight into the Interaction of Malondialdehyde with Rabbit Meat Myofibrillar Protein: Fluorescence Quenching and Protein Oxidation

This research explored the effects of oxidative modification caused by different malondialdehyde (MDA) concentrations on rabbit meat myofibrillar protein (MP) structural characteristics and the interactions between MDA and MP. The fluorescence intensity of MDA-MP adducts, and surface hydrophobicity increased, whereas the intrinsic fluorescence intensity and free-amine content of MPs decreased as MDA concentration and incubation time increased. The carbonyl content was 2.06 nmol/mg for native MPs, while the carbonyl contents increased to 5.17, 5.57, 7.01, 11.37, 13.78, and 23.24 nmol/mg for MP treated with 0.25 to 8 mM MDA, respectively. When the MP was treated with 0.25 mM MDA, the sulfhydryl content and the α-helix content decreased to 43.78 nmol/mg and 38.46%, while when MDA concentration increased to 8 mM, the contents for sulfhydryl and α-helix decreased to 25.70 nmol/mg and 15.32%. Furthermore, the denaturation temperature and ΔH decreased with the increase in MDA concentration, and the peaks disappeared when the MDA concentration reached 8 mM. Those results indicate MDA modification resulted in structural destruction, thermal stability reduction, and protein aggregation. Besides, the first-order kinetics and Stern-Volmer equation fitting results imply that the quenching mechanism of MP by MDA may be mainly driven by dynamic quenching.

Impact of coprophagy prevention on the growth performance, serum biochemistry, and intestinal microbiome of rabbits

BACKGROUND

Coprophagy plays a vital role in maintaining growth and development in many small herbivores. Here, we constructed a coprophagy model by dividing rabbits into three groups, namely, control group (CON), sham-coprophagy prevention group (SCP), and coprophagy prevention group (CP), to explore the effects of coprophagy prevention on growth performance and cecal microecology in rabbits.

RESULTS

Results showed that CP treatment decreased the feed utilization and growth performance of rabbits. Serum total cholesterol and total triglyceride in the CP group were remarkably lower than those in the other two groups. Furthermore, CP treatment destroyed cecum villi and reduced the content of short-chain fatty acids (SCFAs) in cecum contents. Gut microbiota profiling showed significant differences in the phylum and genus composition of cecal microorganisms among the three groups. At the genus level, the abundance of Oscillospira and Ruminococcus decreased significantly in the CP group. Enrichment analysis of metabolic pathways showed a significantly up-regulated differential metabolic pathway (PWY-7315, dTDP-N-acetylthomosamine biosynthesis) in the CP group compared with that in the CON group. Correlation analysis showed that the serum biochemical parameters were positively correlated with the abundance of Oscillospira, Sutterella, and Butyricimonas but negatively correlated with the abundance of Oxalobacte and Desulfovibrio. Meanwhile, the abundance of Butyricimonas and Parabacteroidesde was positively correlated with the concentration of butyric acid in the cecum.

CONCLUSIONS

In summary, coprophagy prevention had negative effects on serum biochemistry and gut microbiota, ultimately decreasing the growth performance of rabbits. The findings provide evidence for further revealing the biological significance of coprophagy in small herbivorous mammals.

Monitoring of Hepatitis E Virus in Wild Lagomorphs in Spanish Mediterranean Ecosystems

Hepatitis E virus (HEV) is an emerging zoonotic pathogen in Europe. Even though swine species are considered the main host of the zoonotic HEV-3 genotype, rabbits are recognized as the main reservoir of the divergent HEV-3ra subtype. However, the role of wild lagomorphs in the epidemiology of this virus in Mediterranean ecosystems is under debate. The aims of this study were to assess exposure of HEV in wild rabbit (Oryctolagus cuniculus) and Iberian hare (Lepus granatensis) populations in southern Spain and to determine potential risk factors associated with HEV exposure in these species. Between 2018 and 2021, blood and fecal samples from 370 wild rabbits and 60 Iberian hares were collected. A total of 29 (6.7%; 95%CI: 4.4-9.1) out of 430 sampled animals showed anti-HEV antibodies. By species, the seroprevalences in wild rabbit and Iberian hare were 6.8% (29/370; 95%CI: 4.2-9.3) and 6.7% (4/60; 95%CI: 0.4-13.0), respectively. Seropositive animals were detected on 17 (26.2%; 95%CI: 15.4-36.8) of the 65 sampled hunting estates. The generalized estimating equations model showed that geographical area was a risk factor potentially associated with HEV exposure in wild lagomorphs in the study region. HEV RNA was not detected in any of the 242 (0.0%; 95%CI: 0.0-1.5) fecal samples tested. This is the first large-scale serosurvey performed in wild rabbits in the Iberian Peninsula and in Iberian hares worldwide. Our results provide evidence of low, widespread, and heterogeneous distribution of HEV among wild rabbit and Iberian hare populations in Spanish Mediterranean ecosystems, which indicates a limited role of wild lagomorphs in the maintenance of the virus and a low risk of transmission of HEV to other species, including humans.

Dietary bamboo leaf flavonoids improve quality and microstructure of broiler meat by changing untargeted metabolome

BACKGROUND

Dietary bamboo leaf flavonoids (BLFs) are rarely used in poultry production, and it is unknown whether they influence meat texture profile, perceived color, or microstructure.

RESULTS

A total of 720 one-day-old Arbor Acres broilers were supplemented with a basal diet with 20 mg bacitracin/kg, 50 mg BLFs/kg, or 250 mg BLFs/kg or without additions. Data showed that the dietary BLFs significantly (P < 0.05) changed growth performance and the texture profile. In particular, BLFs increased birds' average daily gain and average daily feed intake, decreased the feed:gain ratio and mortality rate, improved elasticity of breast meat, enhanced the gumminess of breast and leg meat, and decreased the hardness of breast meat. Moreover, a significant (P < 0.05) increase in redness (a*) and chroma (c*) of breast meat and c* and water-holding capacity of leg meat was found in BLF-supplemented broilers compared with control broilers. In addition, BLFs supplementation significantly decreased (P < 0.05) the β-sheet ratio and serum malondialdehyde and increased the β-turn ratio of protein secondary structure, superoxide dismutase, and glutathione peroxidase of breast meat and total antioxidant capacity and catalase of serum. Based on the analysis of untargeted metabolome, BLFs treatment considerably altered 14 metabolites of the breast meat, including flavonoids, amino acids, and organic acids, as well as phenolic and aromatic compounds.

CONCLUSIONS

Dietary BLFs supplementation could play a beneficial role in improving meat quality and sensory color in the poultry industry by changing protein secondary structures and modulating metabolites.

Use of Moringa oleifera leaves (sole or combined with concentrate) in rabbit feeding: Effects on performance, carcass characteristics and meat quality attributes

Sixty Chinchilla rabbits (28 days old) were divided into three equal groups (n = 20). Rabbits in MOL0 (control) were fed pellets containing 700 g cowpea hay/kg pellet as forage source, whereas rabbits in MOL700 and MOL950 were fed pellets containing 700 and 950 g moringa leaves/kg feed pellets, respectively. Average daily gain and feed conversion ratio was comparable in MOL700 and MOL0, however, it was higher in MOL950. Among the carcass traits, dressing percent was higher while, chilling loss was lower in MOL700 treatment. The Longissimus thoracis muscle of rabbits fed moringa leaves containing pellets (MOL700 and MOL950) had lower saturated fatty acid content, higher C18:3n-3 and total n-3 fatty acids along with lower thrombogenic index value. Hence, incorporating moringa leaves at 70% level is beneficial in terms of improved growth performance and functional attributes of meat than diet- containing sole moringa leaves.

Enhancement of Rabbit Meat Functionality by Replacing Traditional Feed Raw Materials with Alternative and More Sustainable Freshwater Cladophora glomerata Macroalgal Biomass in Their Diets

Today's challenges in the animal husbandry sector, with customers' demand for more beneficial products, encourage the development of strategies that not only provide more sustainable production from the field to the table but also ensure final product functionality. Thus, the current research was aimed at replacing some traditional feed raw materials in rabbit diets with C. glomerata biomass to improve the functionality of meat. For this purpose, thirty weaned (52-d-old) Californian rabbits were assigned to 3 dietary treatments: standard compound diet (SCD), SCD + 4% C. glomerata (CG4), and SCD + 8% C. glomerata (CG8). At the end of the feeding trial, 122-d-old rabbits were slaughtered, longissimus dorsi (LD) and hind leg (HL) muscles were dissected post-mortem, and moisture, protein, and lipid profiles were determined. Results revealed that CG4 treatment can increase protein (22.17 g/kg), total (192.16 g/kg) and essential (threonine, valine, methionine, lysine, and isoleucine) amino acid levels in rabbit muscles. Both inclusions gradually reduced fat accumulation in muscles (CG8 < CG4 < SCD) but improved the lipid profile's nutritional value by decreasing saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) and increasing polyunsaturated fatty acids (PUFA). As the dose of C. glomerata increased, the level of lipid oxidation decreased. Biomass supplementation enhanced PUFA/SFA and h/H levels while decreasing thrombogenicity index (TI) and atherogenic index (AI) levels in rabbit muscles, potentially contributing to the prevention of heart disease. Overall, dietary supplementation with C. glomerata biomass may be a more beneficial and sustainable nutritional approach to functionally enhancing rabbit meat.

Dietary utilization of mealworm frass in rabbit feeding regimes and its effect on growth, carcass characteristics, and meat quality

This study aimed to shed light on the use of mealworm (Tenebrio molitor) frass (TMF) in rabbit diets and its effects on growth performance, blood profiles, rabbit meat quality, and fatty acid profiles. A total of 48 Gabali rabbits were divided equally and randomly into four groups to be fed one of four dietary treatments: a control (T0) group and three TMF groups, which included TMF meal at 1 (T1), 2 (T2), and 3 (T3) %, respectively. The rabbits were fed on isonitrogenous and isoenergetic diets for 11 weeks, and the growth performance data were recorded. Six rabbits per group were slaughtered at the end of the 11th week, then the pharmacochemical parameters and carcass traits were measured, and meat quality and fatty acid profiles were analyzed. The results indicated that the growth performance of different groups was similar (P > 0.05). The levels of globulin, glucose, and alanine transaminase (ALT) were lower in the mealworm frass groups compared with the control group. Carcass traits were not affected by experimental regimes. Fat was higher in the TMF treatment groups, while moisture was lower compared with the control group. The shear force had a lower value in the treatment groups T3 and T2 compared with the control group. The highest values of redness and chroma (color parameter) of rabbit meat were observed in the treatment groups vs. the control group. Moreover, the proportion of total saturated fatty acids in the meat of rabbits that were fed on the T2 and T3 diets was higher compared to those fed on the control (i.e., T0) and T1 diets. Furthermore, the proportion of monounsaturated fatty acid was higher in the T2, T3, and T1 groups vs. T0 rabbits, whereas the PUFA proportions were lower. It could be concluded that frass has great potential to be used as a partial substitute for rabbit diets.

Changes of oxidant-antioxidant parameters in small intestines from rabbits infected with E. intestinalis and E. magna

Rabbit coccidiosis is a very serious disease caused by protozoan parasites of the genus Eimeria, which increases the production rate of free radicals, especially reactive oxygen species. When the generation of free radicals exceeds the scavenging capacity of the body’s antioxidant system, the oxidant-antioxidant balance is broken, resulting in oxidative stress. This study was designed to investigate the effect on the oxidant-antioxidant status of rabbits infected with E. intestinalis and E. magna. To this end, eighteen 30-d-old weaned rabbits were randomly allocated into three groups as follows: the E. intestinalis infection group with 3×103 sporulated oocysts of E. intestinalis, the E. magna infection group with 20×103 sporulated oocysts of E. magna, and the uninfected control group. We measured the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) and the contents of malondialdehyde (MDA) in rabbits’ small intestinal tissues (duodenum, jejunum and ileum) of the three groupson day 8. The results showed that CAT activity and MDA levels significantly increased, while the activities of SOD, GSH-Px and T-AOC decreased after E. intestinalis and E. magna infection. Besides, the jejunum and ileum were particularly damaged in the rabbits. It is concluded that the pathological oxidative stress occurs during the E. intestinalis and E. magna infection process and the body’s oxidant-antioxidant balance is disrupted.

Effect of a Diet Based on Biotransformed Sorghum on Rabbit Intestinal Morphology and Fecal Fiber Composition

Some of the goals of meat production systems are to improve feed efficiency, reduce costs, provide proper nutrition and avoid metabolic disorders. Hence, the aim of this work was to compare a rabbit diet based on untreated sorghum (T1) with a second one that included the cereal biotransformed by the co-cultivation of two basidiomycetes (T2). Their effects on the cereal, diets, and fecal structural fiber composition, as well as on rabbit intestinal morphology, were evaluated. A completely randomized design was applied, employing 24 New Zealand rabbits (21 days old). The fiber chemical composition results indicated that the sorghum treated with the co-culture had lower amounts of neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, hemicellulose and cellulose, as did rabbits fed the T2 diet. Decreases in the NDF, ADF and cellulose contents were detected in T2-nourished rabbit excrements at day 21 (p ≤ 0.05), while lignin percentages diminished at days 35 and 49 (p ≤ 0.05). These rabbits also showed longer jejunal and cecal villi (p ≤ 0.05). The results obtained suggest a positive effect on the bioavailability of structural fibers after sorghum fungal co-fermentation, as their content decreased in rabbit fecal matter without damaging the intestinal morphology.

Low-fat fresh sausage from rabbit meat: An alternative to traditional rabbit consumption

The study aimed at the development of fresh sausages using rabbit exclusively as raw material. The idea was to offer an innovative product to increase rabbit consumption. Also, to meet currently consumers' requirements, a low-fat version was made. Two final formulations, a control sausage and a low-fat version using konjac gum, were developed through an iterative process and stored in a MAP under refrigeration. Sensory, microbiological and physicochemical analyses were carried out on days 1, 6, 8 and 13 after packaging. The shelf-life of the sausages was determined according to a multivariate criterion. Results showed a significant reduction in fat content and energy value. Sensory analysis showed a decrease in characteristic aroma and flavour and an increase in rancid odour, while hardness and fragility decreased in the low-fat treatment. The shelf-life was 7 days for all treatments, concluding that the multivariate method was a powerful technique as physicochemical, microbiological and sensory criteria were considered.

Effects of Dietary Quinoa Seeds on Cecal Microorganisms and Muscle Fatty Acids of Female Luhua Chickens

To study the effects of adding quinoa seed (raw grain) to the diet of the Luhua chicken on the cecal microorganism abundance and fatty acid composition of muscle, 120 49-day-old healthy female dewormed Luhua chickens (body weight 1476.21 ± 101.39 g) were randomly divided into 4 groups, with 3 replicates in each group and 10 chickens in each repetition. The control group (CK group) was fed a basal diet and the experimental groups were fed with 4% (Q4), 8% (Q8), and 12% (Q12) quinoa seed (raw grain) added to the basal diet for 75 days. After 121 days of age, the animals were slaughtered and the 16S rRNA characteristics of cecal flora, as well as composition and content of fatty acids in muscle, were determined and analyzed. The content of unsaturated fatty acids (UFAs), docosahexaenoic acid (C22:6n3; DHA) and n-3 polyunsaturated fatty acids (n-3 PUFAs) in the breast and leg muscles significantly increased in the experimental groups supplemented with quinoa seeds (p < 0.05). However, the content of saturated fatty acids (SAFs) and ratio of n-6/n-3 in breast muscle and leg muscle significantly decreased (p < 0.05). In addition, adding a certain percentage of quinoa seeds in the diet can also affect the community composition and content of microorganisms in the ceca of Luhua chickens. At the phylum level, the Proteobacteria, Actinobacteria, Synergistetes and Melainabacteria in experimental groups (Q4, Q8 and Q12) were significantly lower than those in the CK group (p < 0.05). At the genus level, Desulfovibrio, Synergistes, Olsenella, Parabacteroides, Mailhella, Sutterella and Ruminiclostridiu in group Q4 were significantly lower than those in group CK (p < 0.05) while Faecalibacterium in Q8 group, and Lawsonia and Faecalibacterium in Q12 group were significantly higher than those in the CK group (p < 0.05). Enrichment analysis of the microbial function showed that compared with the CK group, Metabolism and Enzyme Families were significantly enriched in the Q4 group (p < 0.05). Cellular Processes and Signaling were significantly enriched in the Q8 group (p < 0.05). The association analysis of fatty acids with microorganisms showed that the abundance of Faecalibacterium, Lawsonia and Meagmonas was significantly correlated with partial SFAs and UFAs (p < 0.05). In conclusion, adding quinoa seeds to diets significantly increased the content of muscle DHA, UFAs and n-3 PUFAs. The content of SAFs and the n-6/n-3 ratio were significantly reduced. Taken together, quinoa can effectively improve the cecal microbiota structure, inhibit the number of harmful bacteria and increase the number of beneficial bacteria, regulating the intestinal environment and promoting the body health of female Luhua chickens.

Effects of Dietary Oregano Essential Oil on Cecal Microorganisms and Muscle Fatty Acids of Luhua Chickens

This experiment was conducted to investigate the effects of oregano essential oil on the cecal microorganisms and muscle fatty acids of Luhua chickens. One hundred and twenty 49-day-old healthy dewormed Luhua chickens were randomly divided into four groups with three replicates per group and ten chickens per replicate. The corn−quinoa and soybean meal diets were supplemented with 0 (Q8 group), 50 (QO50 group), 100 (QO100 group) and 150 mg·kg−1 (QO150 group) of oregano essential oil, respectively, and the experiment lasted for 75 days. The composition of intestinal flora was detected by Illumina sequencing of the 16S rRNA V4 region, and the composition and content of fatty acids in the muscles were analyzed by gas chromatography. The results showed that dietary oregano essential oil can effectively increase the contents of elaidic acid (C18:ln9t), polyunsaturated fatty acids (PUFAs) and n-3 polyunsaturated fatty acids (n-3 PUFAs) in breast muscle tissues. However, the fatty acid composition and PUFA content in leg muscle tissues were not significantly improved. According to a 16S rRNA high-throughput sequencing analysis, dietary oregano essential oil supplementation with a certain concentration can change the cecal microbial community composition of broilers. At the phylum level, Elusimicrobia in the QO150 group was significantly lower than that in Q8 group (p < 0.05). At the genus level, Phascolarctobacterium, Parasutterella and Bilophila in the experimental groups (QO50, QO100 and QO150) were significantly lower than those in the Q8 group (p < 0.05). An enrichment analysis of the microbial function found that the amino acid metabolism, energy metabolism, metabolism, signal transduction and genetic information processing were mainly enriched in the experimental groups, which promoted the digestion and absorption of nutrients and enhanced intestinal barrier functioning. An analysis of the association between fatty acids and microbes found that the abundance of microbiota was significantly correlated with partially saturated fatty acids (SFAs) and unsaturated fatty acids (UFAs) (p < 0.05). In conclusion, the dietary addition of oregano essential oil can effectively improve cecal microbial community composition, promote the digestion and absorption of nutrients, and enhance intestinal barrier functioning. It can significantly improve the content of some fatty acids, and there was a certain correlation between caecum microorganisms and fatty acid deposition in muscles.

Effect of Bovine Colostrum Dietary Supplementation on Rabbit Meat Quality

Bovine colostrum (BC) is rich in nutrients, antimicrobial, and antioxidant factors; for these reasons, it has been used as supplement in animal nutrition. However, its possible effects on meat quality have not been studied yet. Thirty-nine New Zealand White rabbits (n = 13/group) were assigned to three groups and fed until slaughter with a commercial standard diet, control group (C), and C supplemented with 2.5% and 5% (w/w) of BC (BC-2.5 and BC-5 groups, respectively). After slaughtering, the effect of dietary supplementation on microbiological and chemical characteristics of the rabbit loins was evaluated at 48 h postmortem (D0) and after 3 (D3) and 8 (D8) days of refrigerated storage. Results showed no difference in the microbiological parameters. In the supplemented groups, TBARS and TVBN values were lower and higher than in the C group, respectively (p < 0.01), and their fatty-acid profile was increased in SFA and decreased in MUFA (p < 0.05). In conclusion, research must continue to examine in depth the possible effects of BC byproduct reuse in animal nutrition on meat quality (e.g., antioxidant power, and physical and sensory characteristics).

Investigation of the growth performance, blood status, gut microbiome and metabolites of rabbit fed with low-nicotine tobacco

Tobacco contains a large amount of bioactive ingredients which can be used as source of feed. The objective of this study was to evaluate the effects of dietary addition of low-nicotine tobacco (LNT) on the growth performance, blood status, cecum microbiota and metabolite composition of meat rabbits. A total of 80 Kangda meat rabbits of similar weight were assigned randomly as four groups, and three of them were supplemented with 5%, 10%, and 20% LNT, respectively, with the other one fed with basal diet as control group. Each experiment group with 20 rabbits was raised in a single cage. The experiments lasted for 40 days with a predictive period of 7 days. The results revealed that LNT supplementation had no significant effect on the growth performance, but increased the half carcass weight compared with control group. Dietary supplemention of LNT decreased the triglycerides and cholesterol content in rabbit serum, and significantly increased the plasma concentration of lymphocytes (LYM), monocytes, eosinophils, hemoglobin HGB and red blood cells. In addition, LNT supplementation significantly changed the microbial diversity and richness, and metagenomic analysis showed that LNT supplementation significantly increased Eubacterium_siraeum_group, Alistipes, Monoglobus and Marvinbryantia at genus level. Moreover, LC–MS data analysis identified a total of 308 metabolites that markedly differed after LNT addition, with 190 significantly upregulated metabolites and 118 significantly downregulated metabolites. Furthermore, the correlation analysis showed that there was a significant correlation between the microbial difference and the rabbit growth performance. Overall, these findings provide theoretical basis and data support for the application of LNT in rabbits.

Black soldier fly larvae meal and fat as a replacement for soybeans in organic broiler diets: effects on performance, body N retention, carcase and meat quality

1. Due to the increasing global demand for more sustainably produced animal protein, there is an intensive search for feeds to replace soybeans. Black soldier fly larvae (BSFL) appear to have great potential for replacing soybeans in poultry diets. The main objective of this study was to determine if the nutritional value of BSFL is superior to soybeans when feeding organic broilers, since smaller amounts of BSFL could replace the soybean content in the feed, thus saving even more resources.2. Eighty Hubbard S757, a slow growing organic broiler type, were fattened for 63 d, spending the last 49 d on one of five diets. Two soybean cake- and soybean oil-based diets (SS, SS-) were compared with three diets based on partially defatted BSFL meal and BSFL fat from two origins (AA-, AB-, BB-). Different from diet SS, diets SS-, AA-, AB-and BB- were designed with approximately 20% less lysine and methionine. Growth (n = 16), metabolisability, body nitrogen retention, carcase and meat quality (n = 8) were evaluated.3. Broilers of the insect-based feeding groups, AA- and AB-, grew similarly well compared to those of group SS. They also retained more nitrogen in the body than those fed BB- and SS-. Breast meat yield was higher with AA- and AB- than with BB- and SS-, but still lower than with SS. Dietary variations in physicochemical meat quality were of low practical relevance. Diet BB- resulted in a more yellow skin and meat. The fatty acid profile of the breast meat lipids reflected the high lauric acid proportion of the BSFL lipids, resulting in up to 80 times higher proportions than when feeding the soybean-based diets.4. The results indicate that high-quality BSFL, depending on their origin, may indeed be superior to soybean protein, but that the meat lipids from BSFL-fed broilers can contain significant amounts of lauric acid, which, from a human nutrition perspective, could have a negative impact on meat quality.

Aspergillus awamori attenuates ochratoxin A-induced renal and cardiac injuries in rabbits by activating the Nrf2/HO-1 signaling pathway and downregulating IL1β, TNFα, and iNOS gene expressions

Ochratoxin A (OTA) is one of the most dangerous and that pollute agricultural products, inducing a variety of toxic effects in humans and animals. The current study explored the protective effect of different concentrations of Aspergillus awamori (A. awamori) against OTA (0.3 mg/kg diet) induced renal and cardiac damage by exploring its mechanism of action in 60 New Zealand white male rabbits. Dietary supplementation of A. awamori at the selected doses of 50, 100, and 150 mg/kg diet, respectively, for 2 months significantly improved the rabbit's growth performance; modulated the suppressed immune response and restored the altered hematological parameters; reduced the elevated levels of renal injury biomarkers such as urea, creatinine, and alkaline phosphatase; and increased serum total proteins concentrations. Moreover, it also declined enzymatic activities of cardiac injury biomarkers, including AST, LDH, and CK-MB. A. awamori alleviated OTA-induced degenerative and necrotic changes in the kidney and heart of rabbits. Interestingly, A. awamori upregulated Nrf2/OH-1 signaling pathway. Therefore enhanced TAC, CAT, and SOD enzyme activities and reduced OTA-induced oxidative and nitrosative stress by declining iNOS gene expression and consequently lowered MDA and NO levels. In addition to attenuating renal and cardiac inflammation via reducing IL-1β, TNF-α gene expressions in a dose-dependent response. In conclusion,this is the first report to pinpoint that dietary incorporation of A. awamori counteracted OTA-induced renal and cardiac damage by potentiating the rabbit's antioxidant defense system through its potent antioxidant, free radical scavenging, and anti-inflammatory properties in a dose-dependent response. Based on our observations, A. awamori could be utilized as a natural protective agent against ochratoxicosis in rabbits.

Sample preparation and storage effects on fatty acid profile of rabbit Longissimus thoracis et lumborum muscle

Twenty-five Pannon White male rabbits reared and fed in similar conditions were slaughtered at 11 weeks of age. The longissimus thoracis et lumborum muscles (LTL; right and left) were removed at 24 h post-mortem and allocated to four sampling/storage treatments: the left side of LTL muscle was divided in half perpendicularly, with the posterior portion being analysed within one day (fresh), and the anterior portion vacuum packaged and stored for 1 mo at –20°C (whole-frozen); the right LTL side was ground with half of the product vacuum packaged and frozen for 1 mo at –20°C (ground-frozen), whereas the other half was freeze-dried, vacuum packaged, and stored for 1 mo at 4°C (freeze-dried refrigerated). Treatments impacted percentages of total saturated (P<0.01), monounsaturated (P<0.05), and polyunsaturated fatty acids (P<0.001), whole-frozen treatment affecting the most the fatty acids profile of the meat. Method of preparation and storage of meat samples before performing fatty acid analysis had an impact on the percentage of specific fatty acids, which could render the precision of study-to-study comparisons less reliable.