Physicochemical properties and sensory profile of some breeds of rabbits in Algeria

Abstract

The objective of this study was to compare physicochemical traits and sensory profile of meat from rabbits of both sexes belonging to two genotypes, local population and new line (ITELV 2006) which exhibited better characteristics due to its genetic potential. A total of 60 rabbits at 90 days of age were used in the experiment. At slaughter, meat physicochemical and sensory characteristics were measured on Longissimus lumborum muscle. Differences related to genotype were found in most of the physicochemical characteristics studied like Cooking Losses (P < 0.001), Percentage of Released Water (P < 0.001), Myofibril Fragmentation Index (P < 0.001) and a* value (P < 0.001). However, in some of the traits, the differences were related to interaction of sex and genotype (S*G) as in the case of Cooking Losses (P < 0.001) and b* value (P < 0.01). Regarding SDS-PAGE analysis results, the comparison between two breeds has not shown any particular distinction in the myofibrillar and sarcoplasmic protein profiles in relation to the number and the intensity of bands. No significant differences in the sensory characteristics of the meat were noted (P > 0.05). Interestingly, no relevant differences were found between meat from male and female rabbits in all the variables studied (P > 0.05). It was concluded that meat quality was mainly affected by genotype. Thus, the new line exhibited good physicochemical characteristics compared to the local one. This study is the first to analyse and compare the physicochemical and sensory properties of Algerian rabbit meat.

Keywords

Rabbit meat food quality food physical properties food colour consumer studies

INTRODUCTION

In the Mediterranean basin, rabbit-based food dishes have been a regular part of the diet since the earliest civilisations. Rabbits are easy to raise and environmentally friendly on farms and in backyards (Siddiqui et al., 2023). In Algeria, meat production is mainly based on cattle and sheep farming. These production systems are still unable to meet the protein needs of people to keep this country dependent on the world market (CNIS, 2017). In fact, there is a pressing need for increased animal production to meet the ever-growing demand for animal proteins (Lounaouci-Ouyed et al., 2008; Zerrouki et al., 2004). Rabbit meat consumption is still low and its consumption continues to be negligible. This meat is consumed especially in rural regions by farmers and their families. The consumption is mainly increased during the month of Ramadhan and the winter season or is linked to special events. Additionally, rabbit marketing is still modest, not organised or structured (Sanah et al., 2020, 2022). An estimated production of 8474 t of rabbit meat that is, 1% of the global world production (861 739 t) was registered in Algeria, in 2021 (FAO, 2021). In order to diversify Algeria's animal protein supplies and fulfil the food needs of the population, the livestock sector has initiated several livestock development programmes including rabbit meat production and breeding (Mouhous et al., 2021). Relatedly, meat production efficiency can be enhanced by crossbreeding to acquire the advantage of diversity between rabbit breeds and lines, through complementarity and heterotic effects and to generate new breeds or lines (Balaguer, 2014). In this regard, and in order to provide Algerian farmers with more productive animals and improve the genetic stock for rabbit meat production, a new strain (called ITELV2006) has been created since 2003 with females from the local population adapted to produce all year round in the local conditions, and males from a French INRA strain, heavier and more productive (Bolet et al., 2012).

Indeed, since its diffusion in 2012, this new strain has been the subject of numerous studies, which were first based on describing its reproduction, growth characteristics (Aroun et al., 2021; Belabbas et al., 2019; Sid et al., 2018; Thiziri et al., 2021). The obtained results seem very promising and confirmed the potential use of this line to develop a more efficient rabbit production in Algeria.

Currently, Algerian rabbit meat production is based mainly on the local populations and the new strain which requires, in addition to the morphological and zootechnical characterisation, a good knowledge of organoleptic and sensory meat qualities. To the best of our knowledge, in Algeria, studies about rabbit meat quality characteristics are scarcely reported or non-existent. The researchers pay less attention to the meat quality aspect. This aspect seems very important and deserves an in depth study. It is also interesting to investigate whether the genetic improvement could affect or not the quality characteristics of meat from our local population. In view of the above, the aim of this study was to examine and compare both meat physicochemical traits and sensory attributes of male and female from two Algerian rabbit breeds: the local Algerian population and the new line.

MATERIAL AND METHODS

Animals rearing and slaughter

The experimental protocol was designed according to guidelines on ethical standards of Official Journal of the Democratic and People’s Republic of Algeria relating to veterinary medicine activities and the protection of animal health (N° JORA: 004 du 27-01-1988) and was approved by the ethical committee of University of Mentouri Constantine 1. Algeria. The research was carried out at Biotechnology and Food Quality Laboratory (INATAA, University of Frères Mentouri Constantine 1, Algeria). A total of 60 rabbits, from 2 different genotypes, (30 rabbits per group, 1:1 male: female ratio) were used in this study. Rabbits from local Algerian breed and new line were raised in experimental rabbit station of the technical institute of breeding (ITELV), located in Hamma Bouziane, Constantine, Algeria. Animals were housed in flat deck cages (n = 3 per cage; 50 × 60 × 53 cm). The cage was equipped with a nipple drinker and a feeder for manual distribution of the feed and were fed ad libitum with a commercial pellet diet containing (curde proteins 15%, curde fat 2.5%, crude Ash 10%, crude cellulose 12%; calcium; phosphorus, vitamins (A, E, D3); salt (NaCl), (Telmcen, Algeria). The animals were submitted to a constant photoperiod of 16L: 8D light cycle during the whole experiment period, and were slaughtered by cutting the carotid artery and jugular veins at an average bodyweight of 2078 ± 5 g, and age of 90 day, without prior fasting. The rabbitry was close to the laboratory, so stress due to transport was minimal. Skinned and eviscerated carcases were stored at 4°C. Chilled carcases were divided into three parts according to Rabbit Science Association's (WRSA) recommendations (Blasco and Ouhayoun, 1996). The Longissimus lumborum muscle (LL) located between the first and seventh lumbar vertebrae was removed from both sides of refrigerated carcasses (after 24 hours at 4°C), each sample was divided into two parts: one for physicochemical analyses and the other for sensory assessment. All samples were carefully trimmed of all external fat and connective tissues. The samples were vacuum-packed and stored at −20°C during 10 days, until they were used for further laboratory analysis. The mean of three replicates was used for all of the variables’ analysis.

Meat quality variables

pH

The pH in triplicate was measured 24-hour postmortem in the LL muscle after homogenisation of 1 g of raw muscle for 30 s in 10 ml of sodium iodoacetate (5 mM) and potassium chloride (150 mM) according to McGeehin et al. (2001) using a previously calibrated pH metre (PHS-3CW microprocessor pH/mV metre, BANTE instrument) equipped with a glass combination electrode.

Water holding capacity

Water holding capacity (WHC) of LL muscle was measured according to the Grau and Hamm (1953), also called ‘Filter Paper Press Method,’ with slight modifications of the areas determined. WHC expressed as the ratio of the muscle area to the total area after compression of 300 ± 5 mg of meat for 5 minutes by a 2.25 kg weight (Pla and Apolinar, 2000). Circles of meat (M) and released juice (T) were then carefully drafted on clear plastic for a permanent record and the damp paper-filter was rapidly weighed after accurately removing the compressed meat. The areas were measured using the open source Image J 1.48 software. The areas drawn in clear plastic were scanned and quantified using freehand selection option (Hafid et al., 2016). The percentage of the released water (PRW) was calculated as the ratio of the percentage of weight of released water (damp paper-dry paper) to intact meat ×100.

Cooking losses

Meat cooking losses, CL (%) were determined, as described in Pascual and Pla (2007), 10 g of meat was weighed (P1) and frozen at −20°C. When required, LL muscle samples were continuously boiling water bath. After cooling for 10 minutes by immersion in water, samples were removed from the bags, dried on the surface with a paper towel and weighed (P2). CL (%) were calculated as (P1−P2) × 100/P1.

Determination of myofibril fragmentation index

The myofibril fragmentation index (MFI) was determined according to the turbidity method of Culler et al. (1978) as modified by Li et al. (2012). Protein concentration of the suspension of myofibrils was determined by the colorimetric method of Bradford (1976). Aliquots of myofibril suspensions were diluted in the buffer to a final protein concentration of 0.5 ± 0.05 mg/ml. The Absorbance was immediately measured at 540 nm with a spectrophotometer (Jenway 7305).The mean of the triplicate absorbance readings was multiplied by 200 to obtain the MFI for each sample (Hopkins et al., 2000).

Myoglobin concentration

Pigments in rabbit meat samples were extracted based on the principles of the Faustman and Phillips (2001).The absorbance of the filtrate was measured by a spectrophotometer (Jenway 7305) at a wavelength of 525 nm, using an extinction coefficient of 7.6 mM⁻¹ cm⁻¹ as follows:

[Myoglobin] (mg/g) = [A/(7.6 mM^–1 cm^–1 × 1 cm)] × [17000/1000] × 10 (Canto et al., 2015).

Colour analysis

The colour of the rabbit meat was determined according to the method of He et al. (2020) using the Grab colour-extracting application (version 3.6.1, 2017, Loomatix Ltd, Munchen, Germany). To ensure that the colour capture was not affected by ambient light, a closed polystyrene box (39 × 17 × 28 cm) was used, and integrated with a 1.2 W 5 V white LED to obtain an evenly scattered light on top of the sample. The CIE-L*a*b* colour space mode was chosen. This is a mathematical colour model based on the sensitivity of the human visual spectrum (Chen and Ren, 2014), where the L* value designates lightness, while a* and b* are colour coordinates ( + a* = redness, −a* = green, + b* = yellow, −b* = blue). Colour measurements were taken at five different locations on the same LL muscle. The values of colour saturation (chroma; C*), and colour hue (hue; H*) were calculated using the following formula (Cielab, 1976): H* = tan−1(b*/a*), C* = (a*2 + b*2)0.5.

Polyacrylamide gel electrophoresis

Myofibrillar and sarcoplasmic proteins were extracted according to the procedure described by Joo et al. (1999). A sample of 0.5 g of fresh meat of LL muscle was added to 10 ml of extraction buffer, containing (75 mM KCl, 10 mM KH₂PO₄, 2 ml MgCl₂, 2 mM EGTA, 1 mM NaN₃, pH 7.0). The solutions of extracted proteins (sarcoplasmic and myofibrillar) were stored in eppendorf tubes at −20°C.The protein concentration of both sarcoplasmic and myofibrillar protein extracts was determined by the Bradford method (1976) using bovine serum albumin as the standard. After denaturation, the extracts of the sarcoplasmic and myofibrillar proteins were analysed using one dimensional SDS-PAGE electrophoresis on 3.75% stacking and 12% resolving gels according to Laemmli (1970). For staining, the gel was placed in a Coomassie Brilliant Blue R-250 staining solution for at least 20 minutes with agitation. Finally, the gel is destained by successive washes and agitation in a destaining solution, until the protein bands are clearly visible. A mixture of proteins with a known molecular weight ranging from 10 to 250 kDa (#161-0305) obtained from Bio-Rad Laboratories, Hercules, CA, was used. The molecular weight of the protein bands was calculated using the Un-Scan-It Gel 6.1 analysis programme (Silk Scientific, Orem, UT) (Boudechicha et al., 2016).

Sensory analysis

For the purpose of evaluating sensory quality attributes, an experienced 10-members’ (5 women and 5 men) panel in rabbit meat was appointed. The panel consists of teachers and postgraduate students belonging to ‘Frères Mentouri Constantine 1 University’. The selected panel is already trained in sensory analysis and therefore considered qualified for this type of analysis. In addition, familiarisation and training sessions for judges were undertaken as recommended in International Organisation for Standardisation (1996) and as described by the American Meat Science Association (1995) in order to help the panel to evaluate meat products, increase their sensory knowledge and giving purely qualitative judgements without considering their preferences.

The meat samples were stored at −20 °C during 10 days before undergoing sensory analysis. The samples of LL muscle were thawed at 4 °C for 24 hours before sensory assessment.

To prepare the samples for sensory evaluation, the LL muscle was cut into 10 pieces of equal size (approximately 5 g) according to the taste panel number and placed in labelled and sealed cooking bags. The bags were then immersed in a water bath, and the meat was boiled without salt or spices.

According to Honikel’s (1998) method, the samples were cooked at a constant temperature of 80 °C for approximately 1 hour to reach a core temperature of 75 °C and served hot immediately to the judges in white plates. In each session, the panelist evaluated 2 samples in randomised order, on average; each sample was evaluated by the 10 panelists. A cup containing water (90%) and apple juice (10%) was given to the panel at the beginning of the session and in between samples in order to cleanse the palate between tastes (Hutchison et al., 2012). A list of 11 selected parameters was used (Rabbit flavour intensity, grass odour intensity, rabbit odour intensity, juiciness, tenderness, cohesion, chewiness, fibrousness, flouriness, residual, and the overall appreciation) (Table 1). Each attribute was rated on a 0 (absence of perception) to 10 (very intense perception) using a 10 cm unstructured continuous line, as recommended by the UNE-EN-ISO 4121:2006 standard (AENOR, 2006). Samples were tasted by the trained panel in a normalised tasting room, under white artificial light, according to ISO 8589:1988. A paired preference test was performed to determine whether there is a statistically significant preference between two samples of meat of two breeds and both sexes. The 10 panelists were asked to choose which sample was more preferred according to their sensory properties. Since a forced choice procedure was adopted, a sample must be chosen even if the selection by the assessor was done randomly.

Table 1.

Effect of genotype (G) and sex (S) on physicochemical variables and sensory attributes of Longissimus lumborum muscle of rabbit meat measured at 24-hour post-mortem.

Item	Local breed		New line		RMSE	Significance
Item	M(n = 15)	F(n = 15)	M(n = 15)	F(n = 15)	RMSE	Gen.	Sex.	InterGen*Sex
pH_u	5.85^b	5.86 ^ab	5.87^ab	5.94^a	0.21	Ns	Ns	Ns
WHC (%)	34.81	36.62	37.43	37.12	6.20	Ns	Ns	Ns
PRW(%)	22.82^a	22.52^ab	19.68^c	19.94^bc	3.71	***	Ns	Ns
CL (%)	35.16^a	33.09^b	31.31^c	32.41^bc	2.98	***	Ns	***
MFI	32.11^a	39.91^a	74.84^b	73.94^b	24.60	***	Ns	Ns
Myoglobin	0.0003^a	0.0003^a	0.0002^b	0.0002^b	0.0001	***	Ns	Ns
L*	41.10^ab	45.25^a	39.52^b	41.14^ab	4.58	Ns	Ns	Ns
a*	12.48^b	11.55^b	22.51^a	18.80^a	3.67	***	Ns	Ns
b*	33.23^b	37.08^a	35.30^ab	31.80^b	3.14	Ns	Ns	**
C*	29.52^b	38.89^a	42.00^a	36.95^ab	7.25	Ns	Ns	*
H*	69.36^a	72.92^a	57.84^b	59.51^b	3.66	***	Ns	Ns
Tenderness	5.80	5.58	6.05	6.25	1.05	Ns	Ns	Ns
Rabbit FI	5.13	5.61	5.65	5.56	0.60	Ns	Ns	Ns
Juiciness	4.60	4.24	4.66	4.57	0.73	Ns	Ns	Ns
Chewiness	4.82	4.60	4.27	4.77	0.80	Ns	Ns	Ns
Cohesion	4.60	4.51	4.29	4.09	0.94	Ns	Ns	Ns
Grass OI	2.26	2.37	2.15	2.08	0.40	Ns	Ns	Ns
Rabbit OI	4.54	4.50	4.74	4.78	0.87	Ns	Ns	Ns
Fibrousness	3.20	3.75	4.22	3.54	1.12	Ns	Ns	Ns
Flouriness	4.17	3.88	4.08	4.26	0.96	Ns	Ns	Ns
Residual	3.91	3.98	3.50	4.08	0.73	Ns	Ns	Ns
OAppraisal	5.72	5.80	5.76	6.46	0.75	Ns	Ns	Ns

Means in the same row and effect with unlike superscripts differ at P < 0.05.* P < 0.05; ** P < 0.01; *** P < 0.001. CL: cooking losses (%); F: female; Gen.: genotype; pHu: ultimate pH at 24 pm; Grass OI: grass odour intensity; M: male; MFI: myofibril fragmentation index; Ns: not significant; OAppraisal: overall appreciation; PRW: released water (%); Rabbit FI: rabbit flavour intensity; Rabbit OI: rabbit odour intensity; RMSE: root mean square error; WHC: water holding capacity (%).

Statistical analysis

Depending on the target, different statistical methods were used. The results are given in the form of means and root mean square error (RMSE). First, the data was analysed by least square means procedure of the General Linear Model (GLM), following a fixed effect model that included genotype, sex and their interaction. Residuals were assumed to be independently normally distributed. The model was: Y_ijk = μ + G _i + S _j + GS _ij + e _ijk , where: Y _ijk is the dependent variable, μ = population mean, G _i = effect of ith genotype (i = local, synthetic), S _j = effect of jth sex (j = male, female), GS _ij = effect of genetic group*sex interaction, e _ijk = random error effect. When statistical differences among groups were found (P < 0.05) a Fisher comparison test was used. Second, Chi-square (χ²) test was used to find which type of meat was preferred by the panellists according to breed type and sex. Third, a Pearson correlation analysis followed by principal component analysis (PCA) was performed to evaluate the relationship between physicochemical variables and sensory attributes. All statistical procedures were performed using the statistical software JMP 15 (SAS Institute Inc., Cary, NC, USA). Comparison or correlation was considered statistically significant at a level of P < 0.05.

RESULTS AND DISCUSSION

The effect of genotype and sex on physicochemical variables and sensory attributes of rabbit meat is reported in Table 1.

pH_u

Our results have shown that the ultimate pH (pH_u) was ranged from 5.8 to 5.9. In line with the present study, Kozioł et al. (2015) also suggested that this pH might indicate that rabbit meat has an inferior shelf life compared to the meat of other animal species. Generally, the pH_u is affected by various factors, including pre- and post-slaughter conditions, type of muscle, individual animal characteristics and level of stress. Genotype, sex and their interaction effect have no significant differences on pH_u (P > 0.05, Table 1), but intragroup comparison revealed that there is a difference in pH_u between the two groups of both sexes. Higher pH_u values of rabbit meat originating from new breed and female animals, respectively, compared to local breed and male animals were observed. Our findings are in agreement with the results obtained by Gasperlin et al. (2006) in their study. They found that pH_u values were significantly different for genotype and sex. In the same regard, a recent paper written by Daszkiewicz and Gugołek (2020) have shown that the type of breed and muscle affects pH_u; while sex had no effect on those variables. Another recent research done by Sampels and Skoglund (2021) have found that at 24 hours post-mortem, pH_u was significantly lower in male compared to female rabbits. In contrast, no significant differences between male and female rabbits were observed in other studies (Dalle Zotte et al., 2016; Lazzaroni et al., 2009; Pla, 2008).

Water holding capacity

Water holding capacity (WHC) is an essential measurement to estimate and assess juiciness; consequently, it determines the appearance and palatability of the final product (Huff-Lonergan and Lonergan, 2005). No differences in WHC were found in both groups and sexes. However, when considering the percentage of the released water, a significant difference was found due to genotype (P < 0.001). There was a tendency for the local breed to have higher PRW than the new line (Table 1). In disagreement with the present findings, Daszkiewicz and Gugołek (2020) have found that WHC differed amongst breed, but not due to sex. A similar situation has been observed by Pla et al. (1998) and Pla (2008) in their researches on rabbit meat. In the same context, the results received by Pascual and Pla (2007) on rabbit meat and Smili et al. (2022) on Sahraoui dromedaries of WHC were lower compared to those of the present study.

Cooking losses’ percentage

Referring to the effect of the rabbit breeds on the CL (%), it was found that genotype groups and their interactions with genre have relevant differences (P < 0.001); whereas, no effect of sex was observed on CL (%). The local breed was the highest in CL (%) compared to the new breed. In disagreement with the results of this research, several studies did not find a significant effect of genotype on CL (%) (Dalle Zotte et al., 2015; Metzger et al., 2009; Safaa et al., 2023). While, Sampels and Skoglund (2021), in their research, recorded a significant effect of genotype on LC (%). Compared to the results of this study, lower values of CL (%) of rabbit meat were observed by several studies (Alagón et al., 2015; Nakyinsige et al., 2014; Paci et al., 2013; Sampels and Skoglund, 2021; Radwan et al., 2023); whereas, Dalle Zotte et al. (2015) obtained similar values. Considerably higher values of CL (%) were noted by many authors (Pascual and Pla, 2007; Xiccato et al., 2013; Zeferino et al., 2013), which may be due to the use of different breeds of rabbits and other measuring instruments and methods.

Myoglobin content and colour parameters

Colour, one of the most important characteristics of the technological and culinary quality of meat, is influenced by such factors as animal breed, sex, age, type of muscle, system of feeding, pre-slaughter handling and slaughtering, but mostly depends on the amount of myoglobin present in the muscle tissue (Maj et al., 2012). LL muscle meat of the local breed exhibited a higher level of myoglobin (0.0003 mg/g) for both sexes compared to the new line (0.0002 mg/g). Rabbit genetic group in the present study affected myoglobin concentration (P < 0.001). However, neither the gender nor the S*G interaction produced significant differences in the level of myoglobin of the meat (Table 1). In the same context, the values of L* measured in this experiment were lower than the results of several studies (Kozioł et al., 2015; Maj et al., 2012; Sampels and Skoglund, 2021; Zepeda-Bastida et al., 2019).Whereas, a* and b* values were higher than those obtained by many authors (Daszkiewicz and Gugołek, 2020; Metzger et al., 2009; Pla, 2008; Wang et al., 2016). Similarly, C * and H* parameters were also higher than those recorded by (de Oliveira Paula et al., 2020; Kadim et al., 2008; Pla, 2008; Rotolo et al., 2013). The difference in the results was probably due to the methods or the procedures of measuring colour parameters used for the first time in this study. Consequently, the results obtained in this study cannot be compared with other findings using different methodological approaches. Additionally, the meat colour parameters, measured on the surface of LL muscle 24 hours after slaughter, were not affected by the sex. By contrast, the type of breed and S*G interaction had effect on some colour parameters (Table 1), which indicates that the LL muscle of males and females were similar in colour. Our results agree with those of Maj et al. (2012), who found that genotype affected the rabbit meat colour parameters of the Longissimus dorsi muscle 24 hours after slaughter; suggesting that crossbreeding may be used in practice as a means for changing meat colour. Whereas, in their study, sex did not influence the colour parameters of the muscle at this time point. In a similar vein, Dalle Zotte and Ouhayoun (1998), in their previous paper, found that the L*, a* and b* colour was significantly influenced by genotype. In contrast, Dalle Zotte et al. (2015), in their research, did not show clear connection between rabbit meat colour and genotype. Also, in disagreement with our results, Lazzaroni et al. (2009), in their study, recorded that the muscle colour parameters showed significant differences due to gender in Longissimus lumborum and Biceps femoris rabbit muscles.

Myofibril fragmentation index

Meat tenderness is also related to structural and biochemical properties of skeletal muscle fibres, especially those of myofibrils and intermediate filaments (Veiseth et al., 2001). MFI is the most important index with which to measure the improvement of meat tenderness and proteolysis (Smili et al., 2022). The turbidity method is the most commonly used method to obtain MFI (Nakyinsige et al., 2014). In our experiment, meat samples from the local breed exhibited significantly lower MFI (32.11 for male vs 39.91 for female) than those from the new line (74.84 for male vs 73.94 for female). Genotype showed a significant effect (P < 0.001) on the MFI values; whereas, G*S interaction have no effect on this variable (P > 0.05). Determining the extent of fragmentation of myofibrils when subjected to homogenisation is an indication of the degradation of muscle myofibrillar proteins under post-mortem conditions and the MFI is a useful indicator of the extent of proteolysis reflecting the degradation of key structural proteins, particularly the rupture of the I-band and breakage of inter-myofibril linkages (Taylor et al., 1995). Thus, the weakening of the myofibrillar structure, with the consequent transversal fragmentation of sarcomeres, is a major structural change in myofibrils occurring during meat ageing (Prates et al., 2002). It was demonstrated that the MFI increased with post-mortem storage in many animal species, and it is well related to the meat tenderness profile (Dosler et al., 2007; Nakyinsige et al., 2014; Prates et al., 2001; Smili et al., 2022; Veiseth et al., 2001). Thus, the new strain meat seems to be more tender compared to the local breed meat. MFI values for rabbit LL muscle acquired in this study are somewhat lower compared to those of Nakyinsige et al. (2014) for L. lumborum of rabbit meat as well as those of Smili et al. (2022) for sahraoui dromedary obtained using the same methodological procedures at the same post-mortem time, but our results are higher compared to those of Dosler et al. (2007) applied on the L. dorsi muscle pork at 24 h post-mortem using methods described by Olson and Stomer (1976) and by Hopkins et al. (2000). These differences in the MFI values are probably due to the use of different extraction procedures, the ageing conditions, animal species, muscle types and states of the sample (fresh or frozen and thawed), etc.

SDS-PAGE electrophoresis

Muscle proteolysis by endogenous proteases systems (cathepsins, calpains, caspases, etc.) is the most important phenomenon occurring during meat ageing (Sentandreu et al., 2002). Major changes in muscle protein architecture are associated to the conversion of muscles into meat (Lonergan et al., 2010); such changes are primarily noticeable at the expression levels of the major myofibrillar proteins like myosin, actin, titin, nebulin, troponin-T, desmin and filamin (Paredi et al., 2012). Myofibrillar proteins, accounting for 55–65% of the total muscle protein, are also responsible for meat quality attributes because of their ability to provide textural and functional properties (Chen et al., 2018; Joo et al., 1999). Many factors concur to affect the post-mortem biochemistry of meat, most of them related to animal husbandry and the production system (Bonneau and Lebret, 2010): genotype/breed, sex, age, castration, nutritional status, nutritional management and weight at slaughter (Paredi et al., 2012). Electrophoresis was performed in order to characterise myofibrillar and sarcoplasmic proteins of LL muscle in rabbit meat during the first 24 hours post-mortem of ageing. Comparisons were made between two studied breeds in order to have an overall appreciation of the proteolytic degradation changes of the muscle that occur as part of cellular death and meat ageing process, resulting in the production of protein fragments. The SDS-PAGE results of the myofibrillar and sarcoplasmic protein profiles are depicted on Figure 1. The electrophoretic analysis showed that the myofibrillar protein fraction (Figure 1, left) contained various proteins with major molecular weights (MW) ranging from 17 to 106 kDa. The MW of 16 fragments of low and high MW (17, 18, 22, 24, 27, 30, 38, 43, 50, 51, 56, 67, 76, 86, 98 and 106 kDa, from bottom to top) have been calculated in the myofibrillar profile. The Commassie-stained polyacrylamide gel showed a similarity of the bands’ electrophoretic profile in both rabbit breeds regardless of their sex group. However, the difference was in the intensity of some bands. This means that the profile shows that some bands are more intense compared to others (24, 27, 30, 38, 51 and 86 kDa). Therefore, the concentrations of those bands in the muscles of the two studied breeds are important. Sarcoplasmic proteins, which represent 30–35% of the total muscle protein, are not directly involved in meat tenderness because sarcoplasmic proteins have non-structural functions consisting primarily of enzymes involved in cellular metabolism, which are represented mainly by glycolitic enzymes and myoglobin, yet studies on pigs have indicated that denaturation of sarcoplasmic proteins has an impact on meat quality parameters such as colour and water retention capacity (Joo et al., 1999; Marino et al., 2014).

Figure 1.

SDS-PAGE profiles of myofibrillar and sarcoplasmic proteins extracted from Longissimus lumborum of rabbit meat at 24 h postmortem. Left: Myofibrillar proteins. Right: Sarcoplasmic proteins. M: male; F: female.

According to the electrophoretic profile of the sarcoplasmic fraction, several bands were observed in protein extracts (Figure 1, right). Stained bands 24 h after slaughter had molecular weights of 15, 17, 20, 21, 28, 32, 36, 47, 56, 65, 73, 80, 88, 106 and 113 KDa. In both groups of rabbits, it was noticed that few bands corresponded to MW of 28, 32, 36, 47, 56 and 88 kDa which were bulky and characterised by a great intensity compared to the other bands; this is due to their high concentration in muscle. The comparison between the local and the new line has not shown any particular distinctions in the sarcoplasmic protein profiles of LL muscle in terms of number and intensity of bands. On the other hand, the intensity of sarcoplasmic bands was higher in comparison with myofibrillar pattern, which may suggest an increased rate of glycolysis properly due to several glycolytic enzymes increase in intensity early after animal slaughter (Marino et al., 2014).

Sensory analysis

In rabbit, sensory properties are amongst the main criteria influencing the consumer's choice (Dalle Zotte, 2002), especially regarding tenderness and flavour. These traits can be genetically determined by major genes or by sets of genes to moderate effects. If this is to be the case, sensory quality might be modified by selection or crossing. Even if sensory qualities are determined by a large number of genes with small effects, some breeds can have the favourable alleles in higher proportions than other breeds (Ariño et al., 2007). A quantitative descriptive analysis by a panel of trained assessors is a good way to objectively describe and compare the sensory properties of food products (Lawless and Heymann, 2010). Table 1 and Figure 2 show the average for the scoring of each trait of the sensory analysis. Among eleven sensory attributes of rabbit meat, the panelists scored highly tenderness, overall appreciation, rabbit flavour intensity and rabbit odour intensity. Whereas, the two genotypes were given lower scores for grass OI, fibrousness and residual. Similar findings were produced by Moumen and Melizi (2016), in their paper, on local Algerian rabbit reared in the Aures region (north-eastern part of Algeria), where sensory analysis revealed that meat was very tender, juicy and has a characteristic flavour. In this context, Dalle Zotte (2002) stated that rabbit meat is considered by the traditional consumer to have positive sensory properties: it is tender, lean and delicately flavoured.

Figure 2.

Sensory quality traits of LL muscle meat rabbit of local and new breed. Rabbit FI: rabbit flavor intensity; Grass OI: grass odour intensity; rabbit OI: rabbit odour intensity; OAppraisal: overall appreciation; LM: local male; LF: local female; SM: strain male; SF: strain female.

Martínez-Álvaro and Hernández (2018), in their study on LD muscle of rabbit meat using unstructured continuous line, have found similar scores to our results for some attributes such as: rabbit odour (4.53), rabbit flavour (4.15), juiciness (3.60) and fibrousness (4.50). Genotype and sex and their interaction have no effect on the sensory characteristics of rabbit meat (P > 0.05; Table 1). Our results agree with the study of Gasperlin et al. (2006), who have found that genotype has no effect on the main characteristic of rabbit meat, such as smell, colour, tenderness, juiciness and mouth feel. Similarly, Carrilho et al. (2009), in their research, found that sex has no effect on the sensory characteristics of rabbit meat. In disagreement with our results, Ariño et al. (2007) in their paper, found that line origin has an influence on some sensory traits determining rabbit meat tenderness. Whereas, line effect was not found for other sensory characteristics, or the effect found was very small. Cross tabulations using chi-square are presented in Table 2. Results of a paired preference test showed no statistically significant differences between meat samples from two breeds and sexes. This means that the two samples were essentially identical in terms of preference. This result confirms the previous findings obtained concerning the sensory traits scores attributed by the panelists. It is noteworthy that meat preference is not an intrinsic attribute of the product, but rather a subjective measure relating to the respondents’ affective or hedonic responses (ASTME2263, 2012).

Table 2.

Cross tabulations of paired preference test results according to breed type and sex.

Frequency		χ ²	P-value
Breed
New strain	68	7.43	NS
Local population	52		NS
Sex
Male	56	6.29	NS
Female	64		NS

* = P < 0.05; ** = P < 0.01; and *** = P < 0.001. NS: not significant.

Correlations and PCA

Correlation coefficients between sensory properties and physicochemical traits of rabbit LL muscle are shown in Table 3. These measurements produced higher positive and negative correlation coefficients. The pH_u of meat has a considerable influence on many other meat quality attributes, for example; pH_u was positively correlated with FMI, tenderness, OAppraisal, rabbit OI, H* and negatively with PRW, grass OI, myoglobin, L*, b* and cohesion (r = −0.97; P < 0.05). Strzyzewski et al. (2008) reported that the concentration of hydrogen ions in muscles is also associated with meat colour, similarly, Kozioł et al. (2015) in their research found that pH value of meat 24 hours after slaughter is negatively correlated with the colour parameters L*, b* and C*. Our results are similar to those reported by Sampels and Skoglund (2021) where the ultimate pH was negatively correlated to b* values. The same results were previously observed on broiler breasts (Fletcher et al., 2000). It clearly shows that PRW % parameter has many high correlations with meat quality traits such us : MFI (r = −0.99; P < 0.05), myoglobin (r = 0.99; P < 0.05), rabbit OI (r = −0.96; P < 0.05), and a* and H* (r = −0.96; P < 0.05). Our results are also confirmed high correlation between PRW % and juiciness, grass OI and tenderness. It also appears that there was a very high positive correlation between tenderness and rabbit OI (r = 0.96; P < 0.05), juiciness, flouriness, OAppraisal a* and H*.Whereas, a high negative correlation was found with grass OI (r = −0.99; P < 0.05), cohesion, L* and b*.

Table 3.

Pearson's correlation coefficients between traits of the sensory analysis and physicochemical characteristics of rabbit meat from local and new breed.

Variables	pHu	WHC (%)	PRW(%)	CL (%)	IFM	Myo.	Tend.	R. F.I	Juic	Chewi	Cohe.	G.O.I	R.O.I	Fibro.	Flou.	Resi.	OApp.	L*	a*	b*	C*	H*
pHu	1
WHC (%)	0.,53	1
PRW(%)	−0.77	−0.00	1
CL (%)	−0.58	−0.17	0.85	1
IFM	0.81	0.08	−0.99	−0.87	1
Myo.	−0.80	0.00	0.99	0.80	−0.98	1
Tend.	0.82	−0.01	−0.86	−0.49	0.85	−0.90	1
RFI	0.51	0.46	−0.62	−0.92	0.67	−0.56	0.21	1
Juic.	0.22	−0.68	−0.54	−0.12	0.48	−0.59	0.72	−0.26	1
Chewi.	0.04	0.32	0.51	0.77	−0.50	0.44	−0.06	−0.66	−0.14	1
Cohe.	−0.97	−0.36	0.90	0.72	−0.92	0.92	−0.88	−0.59	−0.35	0.17	1
GOI.	−0.78	0.09	0.86	0.48	−0.84	0.90	−0.99	−0.18	−0.77	0.08	0.85	1
ROI	0.83	0.00	−0.96	−0.70	0.95	−0.98	0.96	0.44	0.65	−0.29	−0.93	−0.96	1
Fibro.	0.16	−0.08	−0.62	−0.89	0.62	−0.54	0.15	0.83	0.04	−0.96	−0.35	−0.16	0.40	1
Flou.	0.53	−0.19	−0.42	0.08	0.39	−0.51	0.81	−0.37	0.78	0.40	−0.51	−0.82	0.64	−0.39	1
Resi.	0.26	0.73	0.40	0.48	−0.34	0.35	−0.09	−0.24	−0.47	0.87	−0.02	0.14	−0.25	−0.73	0.15	1
OAppraisal	0.93	0.64	−0.52	−0.28	0.56	−0.57	0.72	0.27	0.11	0.38	−0.83	−0.67	0.65	−0.16	0.59	0.56	1
L*	−0.25	0.67	0.63	0.25	−0.56	0.67	−0.74	0.14	−0.99	0.26	0.40	0.79	−0.71	−0.17	−0.72	0.56	−0.10	1
a*	0.58	−0.25	−0.96	−0.81	0.93	−0.95	0.80	0.52	0.22	−0.63	−0.76	−0.82	0.91	0.67	0.41	−0.61	0.30	−0.76	1
b*	−0.54	0.04	0.30	−0.20	−0.28	0.39	−0.74	0.42	−0.64	−0.57	0.47	0.74	−0.54	0.53	−0.97	−0.35	−0.66	0.57	−0.25	1
C*	0.37	0.23	−0.64	−0.94	0.67	−0.57	0.19	0.96	−0.14	−0.83	−0.50	−0.17	0.43	0.94	−0.40	−0.48	0.08	0.00	0.60	0.49	1
H*	0.91	0.20	−0.96	−0.78	0.97	−0.97	0.91	0.59	0.47	−0.30	−0.98	−0.89	0.97	0.45	0.52	−0.14	0.73	−0.53	0.86	−0.44	0.54	1

Correlation coefficients written in bold differ considerably (P < 0.05); CL: cooking losses (%); GOI: grass odour intensity; MFI: myofibril fragmentation index; OApp.: overall appreciation; pHu: ultimate pH at 24 pm; PRW: released water (%); RFI: rabbit flavour intensity; ROI: rabbit odour intensity; WHC: water holding capacity (%).

A better picture of the relationships between sensory quality and physicochemical characteristics is shown in the results of the principal component analysis. Figure 3(a) shows the projection of the variables on the plane defined by the two principal components, which explained an 82% of the total variability. The first principal component (horizontal axis) accounted for 56% of the total variance. This axis was explained by PRW (%), myoglobin, cohesion and grass OI on the positive parts which were positively correlated amongst themselves, but negatively correlated with the variables located on the left side of the figure such us: IFM, rabbit OI, tenderness, a*, H* and pH_u. While, the second PC (vertical axis) explained a 25% of variability and mainly characterised by b*, C*, fibrousness and rabbit FI on the positive side. Whereas, on the opposite side we found other traits like: flouriness, CL(%), chewiness and residual. The variables near each other are generally correlated positively and those far from the origin show to be predominant in defining the principal component. It seems that physicochemical characteristics of rabbit meat contributed mostly in defining the first PC that is, they explained a large part of the observed variation, while the sensory properties described typically the second factor. PCA allows an instant visual identification of the variables that are correlated with each other, and with their direction. By plotting the parameters scores for PC1 and PC2, it can be seen how the variables are placed in the multivariate space. Two distinctive groups according to genetic type and sex are presented in the bi-plot (Figure 3(b)). The first two axes were able to discriminate between the local and the new breed groups and between males and females for the selected variables. The rabbits of the local breed are grouped on the right side and the new line rabbits are on the left side. According to the Figure 3(b) and (c) we find that male and female animals of the local breed are located near the first PC and contributed mainly in its definition rather than the new strain group. By observing the right region of the graph reported in (Figure 3(b)), two groups (local male and female breeds) can be differentiated. All the meat samples from those groups have high PRW, myoglobin, cohesion, CL(%), chewiness and grass OI, but the new strain group (male and female) appeared to have high values of IFM, rabbit OI, tenderness, a*, H* and pH_u. The results from this statistical approach reinforce the differences previously described between the two groups studied, where using different breeds (crossbreeding) and sex of animals produces meat with different quality parameters.

Figure 3.

Principal component (PC) analysis of rabbit meat traits quality. a) Projection of the studied variables in the two first components. b) Bi-plot of the animal groups observations on the two first principal components. c) Animals groups contributions (%). pHu: ultimate pH at 24 p.m; WHC: water holding capacity (%); PRW: percentage of the released water (%); CL: cooking losses (%); MFI: myofibril fragmentation index: Rabbit FI: rabbit flavour intensity; Grass OI: grass odour intensity; Rabbit OI: rabbit odour intensity; OAppraisal: overall appreciation; SM: Strain male; SF: Strain female; LM: local male; LF: local female.

CONCLUSION

This study found considerable differences in the physicochemical properties of the LL muscle traits among two rabbit breeds. The results indicate that the meat of the new breed was tenderer and had less cooking losses and less percentage of released water values compared to the local one. Additionally, a high significant difference was found in the myoglobin concentration and the values of some colour parameters between the two groups studied. However, no relevant differences in meat from male compared to female rabbits were found in the aggregate number of the analysed meat quality variables. Sex might be regarded as a minor factor which affected rabbit meat traits. The meat of the new breed appears to have similar sensory properties to those of the local breed commonly consumed by Algerian people. However, results of the present experiment provide further information about meat physicochemical characteristics quality of the new line (ITELV 2006) and confirmed a possible positive effect of the crossbreeding on meat qualities. The results obtained here, could positively influence the acceptability of synthetic rabbit meat by the Algerian consumers.

Footnotes

DECLARATION OF CONFLICTING INTERESTS

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

FUNDING

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Algerian Ministère de l'Enseignement Supérieur et de la Recherche Scientifique.

ORCID iD

Sentandreu Miguel Angel

References

AENOR (2006) Asociación Española de Normalización y Certificación. Norm UNE-EN ISO 4121:2006. Sensory analysis. Guidelines for the use of quantitative response scales (ISO 4121:2003). Asociación Española de Normalización y Certificación (AENOR) editors, Madrid, Spain.

Alagón

Arce

Serrano

, et al. (2015) Effect of feeding diets containing barley, wheat and corn distillers dried grains with solubles on carcass traits and meat quality in growing rabbits. Meat Science 101: 56–62.

American Meat Science Association (1995) Research Guidelines for Cookery, Sensory Evaluation and Instrumental Tenderness Measurements of Fresh Meat. Chicago, IL, USA: National Livestock and Meat Board.

Ariño

Hernández

Pla

, et al. (2007) Comparison between rabbit lines for sensory meat quality. Meat Science 75: 494–498.

Aroun

Tlili

Benamara

, et al. (2021) Histofunctional characteristics of the mammary gland in a synthetic rabbit strain, 12th World Rabbit Congress. Communication BP-03, Nantes, France, p. 4 pp.

ASTME2263 (2012) Standard test method for paired preference test.

Balaguer

(2014) Genetic Analyses of Growth, Carcass and Meat Quality Traits in Maternal Lines of Rabbits and Their Diallel Cross/Análisis Genético de Caracteres de Crecimiento, Matadero y Calidad de Carne en Lineas Maternales de Conejo y en su Cruzamiento Dialélico, Universitat Politècnica de València.

Belabbas

de la Luz García

Ainbaziz

, et al. (2019) Growth performances, carcass traits, meat quality, and blood metabolic parameters in rabbits of local Algerian population and synthetic line. Veterinary World 12: 55.

Blasco

Ouhayoun

(1996) Harmonization of criteria and terminology in rabbit meat research. Revised proposal. World Rabbit Science 4: 93–99.

10.

Bolet

Zerrouki

Gacem

, et al. (2012) Genetic parameters and trends for litter and growth traits in a synthetic line of rabbits created in Algeria. Proc.: 10^th World Rabbit Congress, pp. 195–199.

11.

Bonneau

Lebret

(2010) Production systems and influence on eating quality of pork. Meat Science 84: 293–300.

12.

Boudechicha

Sellama

Hafid

, et al. (2016) Adoption of Proteomics in Traditional Meat Products: The Case of Khliaa Ezir, Food Futures: Ethics, Science and Culture. The Netherlands: Wageningen Academic Publishers, pp. 612–619.

13.

Bradford

(1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry 72: 248–254.

14.

Canto

Suman

Nair

, et al (2015) Differential abundance of sarcoplasmic proteome explains animal effect on beef Longissimus lumborum color stability. Meat Science 102: 90–99.

15.

Carrilho

Campo

Olleta

, et al. (2009) Effect of diet, slaughter weight and sex on instrumental and sensory meat characteristics in rabbits. Meat Science 82: 37–43.

16.

Chen

Ren

(2014) The significance of license plate location based on lab color space. In: 2nd International Conference on Information, Electronics and Computer. Atlantis Press, pp. 78–81.

17.

Chen

Tume

Xiong

, et al. (2018) Structural modification of myofibrillar proteins by high-pressure processing for functionally improved, value-added, and healthy muscle gelled foods. Critical Reviews in Food Science and Nutrition 58: 2981–3003.

18.

Cielab (1976) Colour system. Commission International de l'Eclairage (pp. 231). CIE Publication 36, Paris.

19.

CNIS (2017) Centre National d’Informatique et des Statistiques. 18 https://www.commerce.gov.dz /media/bilan/source/commerce-extérieur-/stat417.pdf.

20.

Culler

Smith

Cross

(1978) Relationship of myofibril fragmentation index to certain chemical, physical and sensory characteristics of bovine longissimus muscle. Journal of Food Science 43: 1177–1180.

21.

Dalle Zotte

(2002) Perception of rabbit meat quality and major factors influencing the rabbit carcass and meat quality. Livestock Production Science 75: 11–32.

22.

Dalle Zotte

Cullere

Rémignon

, et al. (2016) Meat physical quality and muscle fibre properties of rabbit meat as affected by the sire breed, season, parity order and gender in an organic production system. World Rabbit Science 24: 145–154. https://hal.inrae.fr/hal-02636589

23.

Dalle Zotte

Ouhayoun

(1998) Effect of genetic origin, diet and weaning weight on carcass composition, muscle physicochemical and histochemical traits in the rabbit. Meat Science 50: 471–478.

24.

Dalle Zotte

Szendrő

Gerencsér

, et al. (2015) Effect of genotype, housing system and hay supplementation on carcass traits and meat quality of growing rabbits. Meat Science 110: 126–134.

25.

Daszkiewicz

Gugołek

(2020) A comparison of the quality of meat from female and male Californian and flemish giant gray rabbits. Animals 10: 2216.

26.

de Oliveira Paula

Bittencourt

de Oliveira

TLC

, et al. (2020) Rabbit as sustainable meat source: carcass traits and technological quality of meat and of mechanically deboned meat. Research, Society and Development 9: e5029119906–e5029119906.

27.

Dosler

Polak

Zlender

, et al. (2007) Relation of myofibril fragmentation to textural and chemical parameters of aged pork Longissimus dorsi. Acta Agriculturae Slovenica 90: 5–16.

28.

FAO (2021) Données statistiques de la FAO, domaine de la production agricole: Division de la statistique. https://www.fao.org/faostat/fr/#data/QCL. Accessed 03/04/2023.

29.

Faustman

Phillips

(2001) Measurement of discoloration in fresh meat. Current Protocols in Food Analytical Chemistry: F3. 3.1–F3. 3.13. https://doi.org/10.1002/0471142913.faf0303s00

30.

Fletcher

Qiao

Smith

(2000) The relationship of raw broiler breast meat color and pH to cooked meat color and pH. Poultry Science 79: 784–788.

31.

Gasperlin

Polak

Rajar

, et al. (2006) Effect of genotype, age at slaughter and sex on chemical composition and sensory profile of rabbit meat. World Rabbit Science 14: 157–166. https://doi.org/10.4995/wrs.2006.558.

32.

Grau

Hamm

(1953) Eine einfache methode zur bestimmung der wasserbindungim muskel. Naturwissenschaften 40: 29–30.

33.

Hafid

Gagaoua

Boudechicha

, et al. (2016) A comparison of the carcass and meat quality of ISA (F15) spent hens slaughtered at two different ages. American Journal of Food Technology 11: 134–142. https://hal.archives-ouvertes.fr/hal-01568770

34.

Pei

, et al. (2020) Smartphone-based tape sensors for multiplexed rapid urinalysis. Sensors and Actuators B: Chemical 304: 127415.

35.

Honikel

(1998) Reference methods for the assessment of physical characteristics of meat. Meat Science 49(4): 447–457.

36.

Hopkins

Littlefield

Thompson

(2000) A research note on factors affecting the determination of myofibrillar fragmentation. Meat Science 56: 19–22.

37.

Huff-Lonergan

Lonergan

(2005) Mechanisms of water-holding capacity of meat: the role of postmortem biochemical and structural changes. Meat Science 71: 194–204.

38.

Hutchison

Mulley

Wiklund

, et al. (2012) Effect of concentrate feeding on instrumental meat quality and sensory characteristics of fallow deer venison. Meat Science 90: 801–806.

39.

International Organisation for Standardisation (1996) Meat and Meat products; determination of free fat content, ISO 1444.

40.

Joo

Kauffman

Kim

, et al. (1999) The relationship of sarcoplasmic and myofibrillar protein solubility to colour and water-holding capacity in porcine Longissimus muscle. Meat Science 52: 291–297.

41.

Kadim

Mahgoub

Purchas

(2008) A review of the growth, and of the carcass and meat quality characteristics of the one-humped camel (Camelus dromedaries). Meat Science 80: 555.

42.

Kozioł

Maj

Bieniek

(2015) Changes in the color and pH of rabbit meat in the aging process. Medycyna Weterynaryjna 71: 104–108.

43.

Laemmli (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4. nature 227: 680–685.

44.

Lawless

Heymann

(2010) Sensory Evaluation of Food: Principles and Practices. New York, NY: Springer.

45.

Lazzaroni

Biagini

Lussiana

(2009) Different rearing systems for fattening rabbits: performance and carcass characteristics. Meat Science 82: 200–204.

46.

Zhang

Mao

, et al. (2012) Effect of very fast chilling and aging time on ultra-structure and meat quality characteristics of Chinese yellow cattle M. Longissimus lumborum. Meat Science 92: 795–804.

47.

Lonergan

Zhang

Lonergan

(2010) Biochemistry of postmortem muscle-lessons on mechanisms of meat tenderization. Meat Science 86: 184–195.

48.

Lounaouci-Ouyed

Lakabi-Ioualitene

Berchiche

, et al. (2008) Field beans and Brewer’s grains as protein source for growing rabbits in Algeria: first results on growth and carcass quality. In: Proc.: 9th World Rabbit Congress, 10–13 June, 2008, Verona, Italy.

49.

Maj

Bieniek

Sternstein

, et al. (2012) Effect of genotype and sex on meat colour changes in rabbit. Archives Animal Breeding 55: 385–390.

50.

Marino

Albenzio

Della Malva

, et al. (2014) Changes in meat quality traits and sarcoplasmic proteins during aging in three different cattle breeds. Meat Science 98: 178–186.

51.

Martínez-Álvaro

Hernández

(2018) Evaluation of the sensory attributes along rabbit loin by a trained panel. World Rabbit Science 26: 43–48.

52.

McGeehin

Sheridan

Butler

(2001) Factors affecting the pH decline in lamb after slaughter. Meat Science 58: 79–84.

53.

Metzger

Szendrő

Bianchi

, et al. (2009) Effect of energy restriction in interaction with genotype on the performance of growing rabbits: II. Carcass traits and meat quality. Livestock Science 126: 221–228.

54.

Mouhous

Guermah

Djellal

, et al. (2021) Sustainability and profitability of commercial rabbitries in Tizi-Ouzou, Algeria, World Rabbit Science Association. 12th World Rabbit Congress Nantes, France, Communication F, pp. 09, 04 pp.

55.

Moumen

Melizi

MNZ

(2016) The evaluation of organoleptic parameters of rabbit meat, was a notable way to promote the rabbit meat consumption. In: Proc.: 11th World Rabbit Congress - June 15–18, Qingdao, China, pp. 783–786.

56.

Nakyinsige

Sazili

Zulkifli

, et al. (2014) Influence of gas stunning and halal slaughter (no stunning) on rabbits welfare indicators and meat quality. Meat Science 98: 701–708.

57.

Olson

Stromer

(1976) Myofibril fragmentation and shear resistance of three bovine muscles during postmortem storage. Journal of Food Science 41: 1036–1041.

58.

Paci

Preziuso

D’Agata

, et al. (2013) Effect of stocking density and group size on growth performance, carcass traits and meat quality of outdoor-reared rabbits. Meat Science 93: 162–166.

59.

Paredi

Raboni

Bendixen

, et al. (2012) “Muscle to meat” molecular events and technological transformations: the proteomics insight. Journal of Proteomics 75: 4275–4289.

60.

Pascual

Pla

(2007) Changes in carcass composition and meat quality when selecting rabbits for growth rate. Meat Science 77: 474–481.

61.

Pla

(2008) A comparison of the carcass traits and meat quality of conventionally and organically produced rabbits. Livestock Science 115: 1–12.

62.

Pla

Apolinar

(2000) The filter paper press as a method for measuring water holding capacity of rabbit meat. Word Rabbit Sci. Valencia. A, 659–662.

63.

Pla

Guerrero

Guardia

, et al. (1998) Carcass characteristics and meat quality of rabbit lines selected for different objectives: I. Between lines comparison. Livestock Production Science 54: 115–123.

64.

Prates

JAM

e Costa

FJG

Ribeiro

AMR

, et al. (2002) Contribution of major structural changes in myofibrils to rabbit meat tenderisation during ageing. Meat Science 61: 103–113.

65.

Prates

JAM

Ribeiro

AMR

Correia

AAD

(2001) Role of cysteine endopeptidases (EC 3.4. 22) in rabbit meat tenderisation and some related changes. Meat Science 57: 283–290.

66.

Radwan

Maggiolino

Hassanien

, et al. (2023) Dietary utilization of mealworm frass in rabbit feeding regimes and its effect on growth, carcass characteristics, and meat quality. Frontiers in Veterinary Science 10: 1069447.

67.

Rotolo

Gai

Nicola

, et al. (2013) Dietary supplementation of oregano and sage dried leaves on performances and meat quality of rabbits. Journal of Integrative Agriculture 12: 1937–1945.

68.

Safaa

Ragab

Ahmed

, et al. (2023) Influence of polymorphisms in candidate genes on carcass and meat quality traits in rabbits. PLoS ONE 18(11): e0294051.

69.

Sampels

Skoglund

(2021) Quality of carcasses and meat from male and female rabbits. Теория и практика переработки мяса 6: 255–258.

70.

Sanah

Becila

Djeghim

, et al. (2020) Rabbit meat in the east of Algeria: motivation and obstacles to consumption. World Rabbit Science 28: 221–237.

71.

Sanah

Boudjellal

Becila

(2022) Descriptive analysis of rabbit meat marketing parameters in the north-east of Algeria. World Rabbit Sci. 30: 163–180.

72.

Sentandreu

Coulis

Ouali

(2002) Role of muscle endopeptidases and their inhibitors in meat tenderness. Trends in Food Science and Technology 13(12): 400–421.

73.

Sid

Benyoucef

Mefti-Korteby

, et al. (2018) Performances de reproduction des lapines de souche synthétique et de population blanche en Algérie. Livestock Research for Rural Development 30: Article #120.

74.

Siddiqui

Gerini

Ikram

, et al. (2023) Rabbit meat production, consumption and consumers’ attitudes and behavior. Sustainability 15(3): 2008.

75.

Smili

Becila

Della Malva

, et al. (2022) Postmortem muscle protein changes as a tool for monitoring Sahraoui dromedary meat quality characteristics. Foods (Basel, Switzerland) 11: 732.

76.

Strzyzewski

Bilska

Krysztofiak

(2008) Zaleznosc pomiedzy wartoscia pH miesa a jego barwa. Nauka Przyroda Technologie. Uniwersytet Przyrodniczy w Poznaniu 2: 2.

77.

Taylor

Geesink

Thompson

, et al. (1995) Is Z-disk degradation responsible for postmortem tenderization? Journal of Animal Science 73: 1351–1367.

78.

Thiziri

Rabiha

Liza

, et al. (2021) Study of the histofunctional characteristics of the ovarian structures of rabbits of the synthetic strain in the state of pregnancy. 12th World Rabbit Congress Communication BP, - Nantes, France, pp. 31, 34 pp.

79.

Veiseth

Shackelford

Wheeler

, et al. (2001) Comparison of myofibril fragmentation index from fresh and frozen pork and lamb longissimus. Journal of Animal Science 79: 904–906.

80.

Wang

Elzo

, et al. (2016) Comparison of carcass and meat quality traits among three rabbit breeds. Korean Journal for Food Science of Animal Resources 36: 84.

81.

Xiccato

Trocino

Filiou

, et al. (2013) Bicellular cage vs. collective pen housing for rabbits: growth performance, carcass and meat quality. Livestock Science 155: 407–414.

82.

Zeferino

Komiyama

Fernandes

, et al. (2013) Carcass and meat quality traits of rabbits under heat stress. Animal: An International Journal of Animal Bioscience 7(3): 518–523.

83.

Zepeda-Bastida

Martínez

Simental

(2019) Carcass and meat quality of rabbits fed Tithonia tubaeformis weed. Revista Brasileira de Zootecnia 48: e20190074.

84.

Zerrouki

Bolet

Berchiche

, et al. (2004) Breeding performances of local Kabylian rabbits does in Algeria. In: Proc.: 8th World Rabbit Congress, 7-10 September 2004, Puebla Mexico, pp. 371–377.