Meat physicochemical properties, fatty acid profile, lipid oxidation and sensory characteristics from three North African lamb breeds, as influenced by concentrate or pasture finishing diets
This study investigated the meat quality of lambs from three North African breeds (Barbarine, BB; Queue Fine de l’Ouest, QFO; and Noire de Thibar, NT) reared on concentrate (S) or on pasture (P). A total of 18 P and 18 S lambs (20 kg initial body weight) were used, with 6 P and 6 S lambs for each breed. After 67 days, all lambs were slaughtered at 26 kg final body weight and meat quality was studied. The pH of S lambs 1 h post-mortem was lower than that of P lambs (p = 0.001). Water cooking loss, colour and sensory quality were not affected by both factors. The pasture and the concentrate meats had the same proportions of lipids and proteins; however QFO and BB breeds had more intramuscular fat than NT breed. The saturated fatty acid proportion was higher for S than P groups (50.63 vs. 44.48%, respectively) and for QFO compared to other breeds. C18:1 was higher for S groups, while C18:2, C18:3 and CLA were higher for P groups. The S group had higher lipid oxidation, while the QFO breed had the highest TBARS. P lambs may have healthier meat than S lambs and the NT breed had the leanest meat with higher concentration of desirable FAs.
Sheep and goat production should adapt to current market demands if its future want to be secure. It is essential that are found ways to improve the competitiveness of the sector in all areas of the supply chain. Society’s point of view of the conditions surrounding livestock production is changing, and as a consequence, the Common Agricultural Policy (CAP) has been modified to include new environmentally-orientated requirements of farmers seeking subsidies. Sheep and goat production has the advantage over other types of livestock production in that it predominantly involves extensive production systems, but work is still needed to improve animal health and welfare, and food safety. People’s lifestyles are also changing, and the small ruminant sector should work to offer consumers new products presented in new ways, striking a balance between traditional forms of consumption (for example linked to festivities) and modern habits (including the purchasing of convenience products).
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Efecto del sexo y la explotación sobre la calidad de la canal y de la carne del cordero lechal de raza Ojinegra
El presente trabajo pretende caracterizar la calidad de la canal y de la carne de cordero lechal de la raza Ojinegra de Teruel. Para ello se utilizaron 64 corderos lechales, 32 de cada sexo, procedentes de 4 explotaciones comerciales. Los resultados mostraron que la edad al sacrificio, el rendimiento de la canal, las medidas objetivas de la canal y el color instrumental de la grasa y del músculo R. abdominis estuvieron afectados por la explotación de origen (P<0,05). Por el contrario, el sexo tuvo escaso efecto sobre los parámetros estudiados. En cuanto a la composición química de la carne, ni la explotación ni el sexo tuvieron efecto sobre ella (P>0,05). La composición de ácidos grasos intramuscular estuvo más afectada por la explotación que por el sexo, registrándose un efecto significativo de la explotación sobre el contenido de ácido oleico, ácido α-linolénico, ácido linoleico conjugado (9c-11t), el grupo de ácidos grasos poliinsaturados n-3 y la relación de ácidos grasos poliinsaturados n-6/n-3 (P<0,001). Sin embargo, el sexo solo afectó al contenido de ácido linoleico conjugado en la carne (P<0,05). De este trabajo se puede concluir que la calidad de la canal y de la carne de los corderos Lechal de raza Ojinegra está determinada por el factor explotación, mientras el sexo es un factor no determinante. Por ello, para obtener un producto comercial homogéneo, sería necesario definir las condiciones técnicas de producción.
Effects of the FecXR allele of BMP15 gene on the birth weight, growth rate and carcass quality of Rasa Aragonesa light lambs
A new allele of the BMP15 gene (FecXR) that increases prolificacy has been recently described in the Rasa Aragonesa sheep breed. The present study was conducted to evaluate the effects of lamb and maternal genotypes on birth weight, growth and meat quality traits. Two experiments were carried out. In experiment 1, the progeny of heterozygous (R+) and wild-type (++) dams mated to wild-type hemizygous (+) rams from four flocks were tested to estimate the effects of the FecXR allele on birth weight and average daily gains (ADGs) until weaning and slaughter (at approximately 50 and 100 days of age, respectively). Three maternal/lamb genotype groups were studied: wild-type progeny from ++ ewes (females: ++/++, n = 62; males: ++/+, n = 60), wild-type progeny from R+ ewes (females: R+/++, n = 31; males: n = 28 R+/+) and progeny carrying the FecXR mutation born to R+ ewes (females: R+/R+, n = 35; males: R+/R, n = 28). No significant differences were observed in the birth weights or ADGs between the FecXR genotype groups in either female or male lambs. In experiment 2, 37 male lambs (13 ++/+, 12 R+/+ and 12 R+/R) were used to evaluate the effect of the FecXR genotype groups on carcass characteristics and meat quality traits. All lambs were classified within the normal ranges for the “Ternasco de Aragón” commercial category, and no significant differences were observed between the genotype groups. We conclude that birth weight, growth traits, light lamb carcass characteristics and meat quality traits were not affected by the maternal and lamb FecXR genotype combinations that were studied.
Se realizó una serie de 8 experimentos para determinar si se podían agrupar diferentes tipos comerciales de cordero criados en condiciones distintas en función del perfil sensorial de su carne. Los animales pertenecían a uno de los siguientes tres troncos raciales: Ovis aries ibericus, ligeriensis o studeri. Dependiendo del experimento al que pertenecían, los animales eran machos o hembras, destetados o no, criados en confinamiento o al aire libre y sacrificados a 22-24 Kg. ó 10-12 Kg. El muestreo y cocinado se realizaron siempre de la misma manera y todas las muestras fueron probadas por el mismo panel de cata. El estudio estadístico se hizo mediante un GLM, un análisis discriminante y un análisis de correspondencias múltiples. Se puede concluir que en animales muy jóvenes, la genética fue más importante que otros factores, como el sexo, alimentación o destete, en la definición de las propiedades sensoriales de la carne. El análisis discriminante fue capaz de clasificar los animales por el tronco de pertenencia pero no por la alimentación.
Influence of feeding systems on cortisol levels, fat colour and instrumental meat quality in light lambs
Forty-eight lambs were fed as follows: GR, lambs and dams grazed perennial pasture; GR+S, the same as GR except that lambs had access to concentrate; DRL-GRE, lambs in drylot and dams in rationed grazing; DRL, lambs with dams were stall-fed. DRL-GRE and DRL lambs were weaned at 45 days of age. Lambs were slaughtered when they reached 22–24 kg of live weight. Plasma cortisol concentration was determined three times before slaughter. Subcutaneous fat and meat colour, and texture were analysed. The different levels of cortisol did not affect meat quality. Both grazing systems gave yellower subcutaneous fat and redder muscles than drylot lambs. Differences between systems relating to colour and texture of the meat disappeared with ageing time, which supports the idea that grazing systems are a good alternative in order to offer similar meat to that coming from drylot systems to which consumers are accustomed. Subcutaneous fat colour was a suitable method to discriminate between grazing and drylot systems, but not within them.
Consumers (n = 265) tasted semitendinosus (ST), semimembranosus (SM) and gluteo biceps (GB) (right and left) from 180 entire male lambs. Muscles were from three Spanish breeds: Rasa Aragonesa (local meat breed), Churra (local dairy breed) and Spanish Merino. Within breed, three slaughter live weights were considered (10–12, 20–22 or 30–32 kg). Isolated muscles were aged under vacuum package for 1, 2, 4, 8 or 16 days. Consumers evaluated tenderness, flavour quality and overall acceptability. Globally, the three attributes were significantly influenced by breed, slaughter live weight and ageing. Considering breed effect, Churra had the lowest scores for tenderness in the heaviest lambs while Spanish Merino was the most tender at 20–22 kg but there were no differences between either for 10–12 kg lambs. Muscles from the heaviest lambs were considered the toughest and those from the 10–12 kg lambs the most tender. Tenderness improved with ageing, but more for SM and GB. Flavour was better in the lightest lambs and, in general, it was not affected negatively by ageing. Consumers preferred meat from the 10–12 kg lambs in all breeds (the most tender and with the best flavour) and aged for intermediate to long periods (4–16 days). For the three attributes, the ST muscle had the best ratings at short ageing times and GB at long ageing times.
The effects of breed, slaughter weight and ageing time on the meat quality of the three most important Spanish breeds were considered. Two hundred and twenty-five lambs of Rasa Aragonesa-local meat breed-, Churra-local dairy breed- and Spanish Merino were used. Animals (75 of each breed) were slaughtered at three different live weights (10–12, 20–22 or 30–32 kg), and the meat was aged for 1, 2, 4, 8 or 16 days. The meat pH, colour, amount of haem pigments, intramuscular fat, moisture, hydroxyproline content and sarcomere length were measured at 24 h post-mortem. Meat texture was measured by compression after each ageing time. The pH of the samples ranged from 5.50 to 5.58. Meat colour varied with breed and slaughter weight (P 6 0.01), the M. longissimus thoracis was lighter in the youngest animals and in the Churra breed and redder in Merinos. Intramuscular fat increased and moisture decreased for heavier lambs. Differences in collagen were associated with breed (P 6 0.01); total and insoluble collagen contents were higher in the Churra breed. Sarcomere length was only slightly affected by slaughter weight. Meat from the Churra breed had the highest values at high levels of compression. Suckling lambs (10–12 kg) had greater myofibrillar toughness than heavier lambs and ageing strongly influenced myofibrillar tenderness.
Fourty-eight Churra Tensina single male lambs were used to evaluate the effect of different feeding systems on carcass composition and predict the carcass tissue composition from joint composition and carcass measurements. Four treatments were studied: GR, unweaned lambs continuously grazing with ewes; GR + S, the same as the previous group, but lambs had free access to concentrate; DRL-GRE, lambs remained indoors with free access to concentrate and ewes grazed for 8 h/day, thereafter remaining with lambs; and DRL, lambs and ewes were kept in confinement, they had free access to concentrate and dry unifeed respectively. In the DRLGRE and DRL groups lambs were weaned when 45 days old. Lambs were slaughtered at 22– 24 kg live weight. Commercial joints from the half left carcass were obtained, recorded and dissected to determine carcass tissue composition. The feeding system had an effect on the proportion of the carcass tissue composition. GR treatment showed higher muscle (M) (pb0.05) and bone (B) (pb0.001) percentages, and a lower total fat (F) percentage (pb0.001) than the rest of treatments. Hence it revealed higher M/F (pb0.01) and lower M/B (pb0.05) and subcutaneous fat/intermuscular fat ratios (SF/IF; p b0.001). Carcass composition predictions were more accurate for grams than for percentages. In predictions from joint composition, pelvic limb was the most accurate joint for grams (R2=0.84, R2=0.68, and R2=0.77 for muscle, bone, and fat, respectively) as well as for percentage (R2=0.65, R2=0.56, and R2=0.73 for muscle, bone, and fat, respectively). Predictions from carcass measurements were greater in muscle and fat grams (R2=0.87 and R2=0.86 for muscle and fat, respectively) than in percentage (R2=0.58 and R2=0.73 for muscle and fat, respectively). Equations to predict carcass tissue that include carcass measurements are a simple method to assess accurately saleable muscle yield from different lamb feeding systems without involving carcass damage.
Diversification of feeding systems for light lambs: sensory characteristics and chemical composition of meat
Forty-eight light lambs were used to study the effect of feeding systems on the sensory quality and chemical composition of their meat. Animals were divided into four batches as follows: GR: lambs with dams continuously on pasture until slaughter; GR+S: like GR, but the lambs had free access to concentrate; DRL-GRE: lambs in drylot and ewes with rationed grazing; DRL: lambs in drylot with dams indoors. DRL-GRE and DRL lambs were weaned at age 45 days. All lambs were slaughtered on reaching 22-24 kg live weight. Sensory attributes were not affected by the feeding system; grazing systems would therefore be a good alternative to indoor feeding systems. Meat from grazing lambs (GR and GR+S) presented the lowest values of C18:2 n-6/C18:3 n-3 and n-6/n-3, DRL-GRE lambs yielded intermediate values and DRL lambs the highest values. Ewes’ diet during lactation affects the fatty acid composition of the meat of light lambs. The feeding system affected the relationships between the meat’s sensory characteristics and chemical properties. Discriminant analysis using fatty acid composition was able to distinguish between lambs from each feeding system, and could therefore be used as a tool for traceability.
Does forage type (grazing vs. hay) fed to ewes before and after lambing affect suckling lambs performance, meat quality and consumer purchase intention?
The aim of the study was evaluate the use of forage diets (grazing pasture vs. hay) around ewe parturition on the performance and meat quality of suckling lambs (10–12 kg bodyweight). Forty-eight multiparous single bearing ewes from the Churra Tensina breed were used. The experimental treatments were conducted during the last 5 weeks of pregnancy
(pre-partum period) and the 5 weeks of lactation (post-partum period) in a 2 × 2 factorial design. Ewes were fed ad libitum on mountain pastures or pasture hay. Hay was made in late spring from the same pasture paddocks to those grazed in autumn. Results showed that ewes body-weight (BW) and body condition score (BCS) were not affected by forage type
feed around ewe parturition. The week post-partum had a more determinant effect on milk production and composition than forage type pre- and post-partum. The energy-corrected milk yield peaked on first week of lactation (1.39 l/day, P < 0.05), and decreased significantly from week 3 post-partum onwards (1.29 l/day vs. 1.02 l/day, P < 0.05). Forage type supplied to ewes during the pre-partum period did not affect any of the studied variables on lambs.
During post-partum period forage type had effect on lamb ADG, which was higher in grazing system than in hay feed (259 g/day vs. 220 g/day). Consequently, age at slaughter was greater in lambs raised by ewes receiving hay post-partum compared to grazing ewes (36 days vs. 32 days, P < 0.05). Caudal fat colour was affected only by post-partum forage type,
showing grazing group greater redness, yellowness and absolute value of the integral of the translated spectrum (SUM) than that forage type (P < 0.05). Carcasses from lambs raised by post-partum grazing ewes led to a muscle with lower lightness and yellowness and greater redness than hay forage type (P < 0.05). Lambs whose dams grazed presented a higher visual
appraisal score at cutting time, however these differences disappeared as time advanced. Grazing forage had a positive effect on consumer purchasing decision (P < 0.10). In conclusion, forage type in pre-partum period did not affect the studied parameters whereas ewes grazing on mountain pastures after autumn-lambing improved lamb performance without any detrimental effect on carcass and instrumental meat quality.
Se estudió el efecto del sexo sobre la calidad de la canal y de la carne de lechales de raza Ansotana. Para ello se tomaron las siguientes medidas: 1. en la canal, color de la grasa subcutánea, color del músculo Recto abdominal, longitud de la canal y perímetro de la grupa. Se calculó el índice de compacidad de la canal (Kg./cm). A partir de la disección de la espalda se determinó la composición tisular de la canal. 2. en la carne, pH, evolución de color del músculo Longissimus thoracis a lo largo del tiempo, composición química, perfil de ácidos grasos, textura instrumental y análisis sensorial. A partir de los
resultados encontrados se ha concluido que el sexo tuvo un efecto moderado sobre las características de la canal y de la carne de lechales de raza Ansotana, aunque los machos presentaron canales mejor conformadas que las hembras y las hembras tendieron a presentar mayor cantidad de grasa subcutánea que los machos. La carne de las hembras presentó mayor proporción de ácidos grasos poliinsaturados y una mayor proporción de ácidos grasos de las series omega-3 y omega-6 que los machos, pero la relación omega-6/omega-3 fue mejor en los machos. No se detectaron diferencias importantes entre sexos en la calidad sensorial de la carne.
Forty-eight single male lambs were used to evaluate the effect of feeding systems on carcass characteristics and fat depots of Churra Tensina light lambs. Four treatments were studied: GR, lambs and ewes were continuously grazing, no concentrate was available to them and lambs were unweaned; GR+S, as the previous one, but additionally lambs had free access to concentrate; DRL−GRE, lambs remained indoors with free access to concentrate and ewes grazed during 8 h a day, thereafter remaining with lambs; DRL, lambs and ewes were kept always in confinement, ewes had free access to dry unifeed and lambs to concentrate. In DRL−GRE and DRL lambs were weaned at 45 days old. When lambs reached 22–24 kg of live-weight they were slaughtered.
Feeding system had effect on growth rates (pb0.05), age (p b 0.001) and live-weight at slaughter (p b 0.01), carcass weight (p b 0.001), dressing percentage (p b 0.001), fatness thickness (p b 0.01) as well as on the subjective classification parameters, as carcass conformation score (p b 0.001), fatness degree (p b 0.01) and KKCF score (p b 0.01), having the GR lambs lower values than the rest of treatments. Nevertheless, carcasses from grazing animals were classified within the
normal ranges for Ternasco commercial category similar to drylot systems. Treatment had effect on pelvic (p b 0.01) and carcass compactness (p b 0.001) being GR carcasses less well conformed. Feeding system affected the total body fat depots (p b 0.01), presenting GR the lowest amount. In all treatments, carcass fat depot was greater than internal fat depots (abdominal, pelvic and renal) (p b 0.05). Grazing treatments (GR and GR+S) presented higher proportion of anterior-rib
and lower proportion of breast in relation to indoor lambs (DRL−GRE and DRL). The feeding system did not affect the proportion of first category of commercial meat. It was concluded that light lamb carcass characteristics were slightly affected by the feeding systems, being carcasses from grazing lambs classified within the normal ranges for Ternasco commercial category, similarly to drylot systems. The small differences among the products of different feeding
systems had no commercial constraint in the light lamb meat market.
Consumer segmentation based on convenience orientation and attitudes towards quality attributes of lamb meat
Food consumption patterns in general and those of meat in particular are constantly changing. These changes are due to wide-ranging, socio-economic and cultural trends but also to the specific lifestyles of increasingly diversified groups of consumers. One of the main trends in meat consumption relates to convenience orientation and meat avoidance. We have used a modified food-related lifestyle (FRL) framework to analyse the current state of lamb meat consumption in a region of Spain, where this has steadily decreased over the past few years. We have focused on two aspects of the FRL framework: cooking habits and consumption situations, in order to establish customer convenience orientation. Other aspects of the FRL, referring to consumers’ perception of quality and shopping methods, together with various socio-economic features, are used to characterise the convenience profiles of consumers and analyse their differences. Data were collected by means of a probabilistic stratified postal survey and analysed with multivariate techniques (Multiple Correspondence Analysis and Cluster Analysis). The objective was to identify, characterise and compare profiles of lamb meat consumers according to their convenience orientation. These consumer profiles could be termed traditional, uninvolved, adventurous and careless. Satisfaction derived from cooking and time spent on cooking, tendency towards eating out, preference of foreign vs. traditional recipes and for the diversification of meals, were the most important factors to distinguish between consumer profiles. Other factors relating to eating out on working days, the importance placed on planning meals, celebration meals, or a preference for informal dinners, did not discriminate between consumer profiles. In relation to the perception of intrinsic quality attributes, no differences were observed for the importance placed on fat content and type of animal, although a fresh appearance and light colour of the meat were more highly valued by traditional consumers.
With regard to extrinsic quality attributes, easy cooking was very important for uninvolved consumers. In general, the presence of a quality label, the local origin of the meat and a feeding system based on pasture or green forages rather than on grains were highly valued by most consumer profiles. In socioeconomical terms, convenience orientation was more related to age, place of residence and level of studies than to income and gender. The identification of different convenience orientations towards lamb meat and the associated perceptions of different quality attributes and socio-demographic features may provide an opportunity for the industry to develop consumer-led products, especially in highly
undifferentiated meat products such as lamb.