Impact of pre-slaughter transport conditions on stress response, carcass traits, and meat quality in growing rabbits

Navel orange peel hydroethanolic extract as a phytogenic feed supplement: impacts on growth, feed intake, nutrient digestibility, and serum metabolites of heat stressed growing rabbits

Currently, using agricultural wastes in animal production has gained worldwide interest. Hence, herein, an eight-week trial was performed to explore the effects of supplemental navel orange peel extract (NPE) on the growth, feed utilization, nutrient digestibility, antioxidant, and hematological parameters of heat-stressed rabbits. In total, 75 weaned rabbits were randomly assigned into five groups. The first group was reared in the winter (mild weather) and fed an untreated pelleted diet (W-NPE-0; control). The other four groups were reared in the summer (hot climate) and fed the control diet fortified with 0 (S-NPE-0), 250 (S-NPE-250), 500 (S-NPE-500), or 1000 (S-NPE-1000) mg NPE/kg diet. The results indicated that thermal-stressed rabbits (S-NPE-0) had significantly lower feed intake, growth performance, hematological indices, serum lipid profile, and antioxidative status, but higher lipid peroxidation compared to the W-NPE-0 group. However, the highest final weight and feed intake were recorded in the S-NPE-1000 group compared with the S-NPE-0 group. Also, supplemental NPE in the growing rabbit diet, especially the S-NPE-1000 group, enhanced the hematological and antioxidative indicators. In conclusion, NPE supplementation in growing rabbit diets could be used to efficiently mitigate the detrimental effects of chronic temperature stress on performance, hematobiochemical features, and oxidative stability.

Improving animal welfare status and meat quality through assessment of stress biomarkers: A critical review

Stress induces various physiological and biochemical alterations in the animal body, which are used to assess the stress status of animals. Blood profiles, serum hormones, enzymes, and physiological conditions such as body temperature, heart, and breathing rate of animals are the most commonly used stress biomarkers in the livestock sector. Previous exposure, genetics, stress adaptation, intensity, duration, and rearing practices result in wide intra- and inter-animal variations in the expression of various stress biomarkers. The use of meat proteomics by adequately analyzing the expression of various muscle proteins such as heat shock proteins (HSPs), acute phase proteins (APPs), texture, and tenderness biomarkers help predict meat quality and stress in animals before slaughter. Thus, there is a need to identify non-invasive, rapid, and accurate stress biomarkers that can objectively assess stress in animals. The present manuscript critically reviews various aspects of stress biomarkers in animals and their application in mitigating preslaughter stress in meat production.

Technological interventions in improving the functionality of proteins during processing of meat analogs

Meat analogs have opened a new horizon of opportunities for developing a sustainable alternative for meat and meat products. Proteins are an integral part of meat analogs and their functionalities have been extensively studied to mimic meat-like appearance and texture. Proteins have a vital role in imparting texture, nutritive value, and organoleptic attributes to meat analogs. Processing of suitable proteins from vegetable, mycoproteins, algal, and single-cell protein sources remains a challenge and several technological interventions ranging from the isolation of proteins to the processing of products are required. The present paper reviews and discusses in detail various proteins (soy proteins, wheat gluten, zein, algal proteins, mycoproteins, pulses, potato, oilseeds, pseudo-cereals, and grass) and their suitability for meat analog production. The review also discusses other associated aspects such as processing interventions that can be adapted to improve the functional and textural attributes of proteins in the processing of meat analogs (extrusion, spinning, Couette shear cell, additive manufacturing/3D printing, and freeze structuring). '.

Stress responses in camels subjected to different rest periods (0 and 12 h) at slaughterhouse

This study investigated the effect of two different rest periods (R0: no rest time, and R12: 12 h of rest) on several stress indicators, including plasma and serum stress parameters, in dromedary camels (Camelus dromedarius). This study involved 60 healthy male dromedary camels aged 5 years, from which blood samples were collected. Cortisol, glucose, urea, creatinine, the enzymatic activity of creatine kinase, lactic dehydrogenase, aspartate aminotransferase, alanine aminotransferase, and alkalinephosphatase were analyzed. Data obtained indicated that rest time had a significant effect on cortisol, creatinine, creatine kinase, lactic dehydrogenase and aspartate aminotransferase (p < 0.05). However, no statistically significant effect was found for glucose, urea, alanine aminotransferase, and alkalinephosphatase. The values of cortisol and creatinine showed a significant decrease at R12. In contrast, the enzymatic activity of creatine kinase, lactic dehydrogenase, and aspartate aminotransferase, significantly increased at R12. Additionally, several correlations between different studied parameters were documented, including for lactic dehydrogenase. The results obtained in this study suggest that rest time may influence welfare indicating parameters. In summary, a rest time of more than 12 h is recommended in order to allow camels to recover from the effects of pre-slaughter stress. Additionally, lactate dehydrogenase might be suitable to use as an indicator of stress in camels during the slaughter process.

Hierarchical clustering as a tool to develop a classification scheme for rabbit meat quality

<p>This study aimed to characterise the quality of meat from commercially-raised rabbits. Animals came from five different producers and were  laughtered in three different plants under provincial or federal inspection jurisdiction. Animal behaviour evaluated by scan sampling prior to feed withdrawal (FW) and transport, as well as blood lactate concentration at exsanguination, did not raise concerns with respect to stress. Stomach pH was higher (<em>P</em>=0.047) when the FW time was short (≤13.5 h), at a mean value of 2.23. All pH values measured 1 h post-mortem from the Biceps femoris (BF) and almost all (97.6%) from the Longissimus lumborum (LL) were higher than 6. Values for ultimate pH measured 24 h postmortem(pH_u) ranged from 5.80 to 6.83 and from 5.70 to 6.70 for BF and LL muscles, respectively. The maximum meat drip loss recorded was 2.6%, while cooking loss reached 30%. Meat lightness (L*) and colour intensity (C*) for the long FW times (≥23 h) were no different from those with short and intermediate (15.5 to 17.3 h) FW times. However, these colour parameters were higher for the short FW time class compared to the intermediate FW time class (<em>P</em>&lt;0.02). A hierarchical cluster analysis based on pH_u, cooking loss and lightness (L*) from 200 rabbit loins was performed. Of the four clusters created, clusters 1 and 2 had the best and second-best meat quality, respectively. Clusters 3 and 4 had the lowest meat quality and presented DFD-like (dark, firm and dry) characteristics. Meat did not exhibit PSE-like (pale, soft, exudative) characteristics, even for the slaughter lot with the minimum mean pH_u. Of the eight slaughter lots evaluated, more than 50% of the meat from three of them fell into clusters 3 and 4; all three were in the intermediate FW time class. Overall, the quality of rabbit meat analysed was acceptable for commercial use, but rather variable. This suggests that there are factors within the value chain that are not yet fully controlled and require further investigation.</p>

Supplementation of Moringa oleifera leaf powder orally improved productive performance by enhancing the intestinal health in rabbits under chronic heat stress

Heat stress jeopardizes animal's growth and health mainly through induction of oxidative stress and inflammation. The current study investigated the effects of Moringa oleifera leaf powder (MOLP) supplementation on productive performance and intestinal health of rabbits under chronic heat stress (HS). Young New Zealand White rabbits (male) at the age of 32 weeks (n = 21, mean body weight of 3318 ± 171 g) for four weeks' period were reared on commercial pelleted diet and divided into three groups: control (CON, 25 °C), HS (35 ± 1 °C) and HS (35 ± 1 °C) with MOLP (HSM) supplemented orally (200 mg/kg body weight). The results demonstrated that rabbits in the HSM group had reduced rectal temperature, respiration rate and improved FCR due to improved daily gain and better crude fiber (NDF) digestibility (P < 0.05) compared with HS group. MOLP improved intestinal integrity and function as indicated by lower serum diamine oxidase level and increased jejunal weight, length, villus height and ratio of villus height to crypt depth than heat-stressed rabbits. MOLP reversed the increased levels of serum cortisol, metabolic indicators i.e. glucose, insulin, and reduced concentrations of serum triiodothyronine. MOLP supplementation also significantly down-regulated the mRNA expression of tumor necrosis factor alpha (α), heat shock protein A2, glutathione peroxidase-1, interleukin (IL)-1α and increased the expression of IL-6. In conclusion, MOLP supplementation could enhance intestinal health along with production and metabolic indicators by alleviating the oxidative stress and inflammatory response in small intestine of hyper-thermic rabbits.

Stunning methods and slaughter of rabbits for human consumption

This opinion on the killing of rabbits for human consumption (‘slaughtering’) responds to two mandates: one from the European Parliament (EP) and the other from the European Commission. The opinion describes stunning methods for rabbits known to the experts in the EFSA working group, which can be used in commercial practice, and which are sufficiently described in scientific and technical literature for the development of an opinion. These are electrical stunning, mechanical stunning with a penetrative and non‐penetrative captive bolt and gas stunning. The latter method is not allowed in the EU anymore following Council Regulation (EC) No 1099/2009, but may still be practiced elsewhere in the world. Related hazards and welfare consequences are also evaluated. To monitor stunning effectiveness as requested by the EP mandate, the opinion suggests the use of indicators for the state of consciousness, selected on the basis of their sensitivity, specificity and ease of use. Similarly, it suggests indicators to confirm animals are dead before dressing. For the European Commission mandate, slaughter processes were assessed from the arrival of rabbits in containers until their death, and grouped in three main phases: pre‐stunning (including arrival, unloading of containers from the truck, lairage, handling/removing of rabbits from containers), stunning (including restraint) and bleeding (including bleeding following stunning and bleeding during slaughter without stunning). Ten welfare consequences resulting from the hazards that rabbits can be exposed to during slaughter are identified: consciousness, animal not dead, thermal stress (heat or cold stress), prolonged thirst, prolonged hunger, restriction of movements, pain, fear, distress and respiratory distress. Welfare consequences and relevant animal‐based measures (indicators) are described. Outcome tables linking hazards, welfare consequences, indicators, origins, preventive and corrective measures are developed for each process. Mitigation measures to minimise welfare consequences are also proposed.