Intramuscular fatty acid composition of “Galician Mountain” foals breed: Effect of sex,slaughtered age and livestock production system

The effects of sex, slaughtered age (9 vs. 12 months) and livestock production system (freedom extensive system vs. semi extensive system) of “Galician Mountain” foals breed on the fatty acid composition were studied. The sex and slaughtered age of the animals had no statistical significance in the intramuscular fatty acids. Furthermore, the livestock production system showed differences in the fatty acid profiles from the Longissimus dorsi. The feeding system showed significant differences in PUFA content (P < 0.001) higher in freedom extensive production system that semi extensive system, whereas MUFA content was significantly (P < 0.001) higher in semi extensive system. This major PUFA content in freedom extensive production showed a significant (r = 0.70, P < 0.01) correlation with C18:3n− 3 content and can be attributed to their eaten only pasture until slaughtered. The higher MUFA contents (P < 0.001) observed for semi extensive production system foals were very significant (r = 0.98, p < 0.01) correlated with C18:1cis−9 content and less significant (r = 0.81, P < 0.01) correlated with C16:1cis−9 content. In addition, the data reinforced the evidence that foals from extensive production system on wood pasture have a higher nutritional quality (mainly due to the higher levels of n−3 PUFA) when compared to concentrate-fed foals, as a result of the beneficial effects of grass on meat fatty acid profiles.     

Meat quality and intramuscular fatty acid composition of Sanfratellano and Haflinger foals

The goal of the trial was to evaluate meat quality, with an emphasis on intramuscular fatty acid composition, of Sanfratellano foals, compared to that from Haflinger foals,both slaughtered at 18 months of age. Thirty foals, half of Sanfratellano breed and half of Haflinger breed, naturally weaned at 7-8 months, were divided into two homogeneous groups at 15 months of age and fed a finishing diet based on polyphite hay and concentrate. The finishing period lasted three months. Sanfratellano foals showed higher slaughter weight (P<0.05) as well carcass weight (P<0.05) compared to Haflinger foals. Meat physical and proximate analyses did not discriminate the two groups. Normal pH values (5.6-5.7) measured at 4-6 day post mortem were recorded in meat from both groups. Shear force values accounted (range 55-58N) for a favourable tenderness in both groups. The intramuscular fat level was low in both groups (<2.5%) supporting the healthy image of this meat. The proportion of linolenic acid was higher (P<0.01) in Haflinger meat than in Sanfratellano one, thus causing a higher (P<0.05) total n-3 fatty acid content. Overall meat from both groups showed a favourable repartition among saturated (36-37% total FAME's), monounsaturated (33% total FAME's) and polyunsaturated fatty acids (30-31% total FAME's).     

Effect of age at slaughter on chemical traits and sensory quality of Longissimus lumborum muscle in the rabbit

The effect of age on chemical composition and sensory quality of longissimus lumborum muscle was investigated in rabbits slaughtered at 11 weeks or 18 weeks of age. Intramuscular fat (IMF) content increased from 1.3 to 2.2%, crude protein content ranged from 23.4-26.9%, whereas water content declined from 74.0 to 69.3%, as the age increased. The sensory quality was assessed by a 10-member experienced sensory panel. The age was found to affect meat tenderness, whereas juiciness and flavour did not differ significantly between ages. A positive trend was observed between tenderness and IMF content, both within age and between ages. Therefore, differences in sensory quality of rabbit meat were at least partly related to IMF content.     

Effects of outdoor rearing and sire breed (Duroc or Yorkshire) on carcass composition and sensory and technological meat quality

The effects of outdoor rearing and sire breed on carcass composition and technological and sensory meat quality in pigs were studied in a trial with 102 crossbred slaughter pigs (Yorkshire, or Yorkshire × Landrace sows and Duroc or Yorkshire as terminal sire). Half of each litter were reared conventionally indoors, while the remainder were reared outdoors in a 50 000 m(2) area, as a single group. All pigs were fed ad libitum. Yorkshire sired pigs had significantly leaner carcasses and meat with lower IMF content and marbling scores, and higher shear force and water content. The sire breeds did not differ regarding pH(u), water-holding capacity, or colour. Meat from the Yorkshire crosses was more acid, less tender and gained lower overall acceptance scores in the sensory test. The outdoor-reared pigs had lower daily gain values and leaner carcasses. They produced meat with lower pH(u), higher drip loss, higher shear force values and higher internal reflectances. Their meat contained more lactate and crude protein and had a higher glycolytic potential, less IMF and less water. Regarding the sensory qualities, outdoor rearing impaired tenderness, juiciness and overall acceptance.     

Characterisation of young bulls of the Bruna dels Pirineus cattle breed (selected from old Brown Swiss) in relation to carcass, meat quality and biochemical traits

Seventy-four young bulls of the Bruna dels Pirineus beef cattle breed were reared in a typical production system and slaughtered at an average age of 381 days and live weight of 541 kg. The animals were evaluated for productive traits, carcass quality, meat quality, eating quality and biochemical characteristics of m. longissimus thoracis (LT). Biochemical measurements included intramuscular fat (IMF) and collagen proportion, haem pigment concentration, lactate dehydrogenase and isocitrate dehydrogenase activities and type I (MHC I) fibre percentage determined by ELISA. Bruna dels Pirineus bulls achieved high growth rates during the fattening period (1.63 kg/day) and showed good carcass quality, with a high dressing-out proportion (607 g/kg, hot carcass), a good conformation score (U; EUROP) and a moderate fatness score (3;1-5). Carcass composition was estimated from the sixth rib joint dissection (682 g/kg lean proportion, 127 g/kg total dissectable fat and 163 g/kg bone). IMF (24.3 g/kg) and MHC I (27.9%) showed high variabilities (CV>30%). Sensory analysis of LT included beef and livery odour and flavour intensity, and overall tenderness and juiciness assessment of loin samples (14-day ageing). Beef odour and flavour were slightly positively correlated with IMF and carcass fatness score (P<0.05). Fatness, MHC I, insoluble collagen and cooking losses tended to affect the livery flavour intensity positively. This variable was significantly higher in meat from bulls of lower carcass quality (i.e. lower conformation score, lower lean proportion; P<0.05) and higher type I fibre percentage. Loin overall tenderness and juiciness were not affected by the biochemical traits studied, however, they were negatively affected by cooking loss (P<0.05).     

不同月龄莱芜黑山羊屠宰性能及肉质比较研究

通过测定屠宰率、pH值、肉色、蒸煮损失、粗蛋白含量、粗脂肪含量、快/慢肌纤维数量等指标,综合分析莱芜黑山羊的屠宰性能、营养品质和加工品质,并进行感官品质评价。结果表明:不同月龄莱芜黑山羊各指标间存在不同程度的差异显著性,12月龄莱芜黑山羊屠宰率(48.21%)与24月龄(48.75%)不存在显著差异,并显著高于8月龄(43.55%),其肉骨比为4.04,低于8月龄及24月龄;8月龄的莱芜黑山羊肉色与其他月龄相比更加红亮,8、12、24月龄的粗蛋白含量分别为19.29%、21.34%、22.00%,粗脂肪含量分别为1.83%、2.08%、2.10%,8月龄的莱芜黑山羊肉剪切力为4985.98 g,显著低于12、24月龄,嫩度最好,且快肌纤维数量及快/慢肌纤维数量比例最高,为6.36,与其他月龄相比差异显著,同时感官评分最高。因此,8月龄莱芜黑山羊肉可作为高档羔羊肉进行生产,以羔羊胴体销售时,12月龄屠宰效益较高。     

Conjugated Linoleic Acid (CLA) content of meat from three muscles of Massese suckling lambs slaughtered at different weights

Eighteen Massese male lambs, fed mainly maternal milk were slaughtered at 11, 14 and 17kg. Samples of Longissimus Dorsi (LD), Triceps Brachii (TB) and Semimembranosus (Sm) muscles were collected. Milk from the lamb's dams was sampled weekly. Fatty acid composition of milk and meat was determined. TB was the fattest muscle, Sm the leanest one and LD showed an intermediate value of total lipids, while the weight at slaughter did not influence total intramuscular fat content in any muscle. Although slaughter weight slightly affected overall fatty acid composition of muscles, rumenic acid and total CLA content in TB and Sm, but not in LD, significantly increased with slaughter weight. As regard milk fatty acid composition, the contents of total CLA, RA and others minor CLA isomers decreased during the first four weeks after lambing and then increased at the last control (five weeks). The animals slaughtered at a live weight of 14 and 17kg showed a greater SCD enzyme activity (estimated by product/substrate ratio) and a higher rumen activity (estimated by means of branched chain and odd chain fatty acid content in meat) than animals slaughtered at 11kg. Cis-7, trans-9 CLA content significantly increased with the slaughter age in TB and SM, while trans-7, trans-9 CLA, only increased in TB, and cis-8, cis-10 CLA, only increased in SM. Further studies are needed in order to verify weather the different behaviour of RA in LD muscle may be due to differences in muscle metabolism or fatty acid utilisation.     

不同屠宰方式对蒙古羊应激及羊肉食用品质的影响

以内蒙古蒙古羊为研究对象,对比分析抹脖子屠宰、掏心式屠宰及电击晕屠宰对蒙古羊应激及羊肉食用品质的影响,利用生化分析仪等仪器对蒙古羊血液指标及食用品质进行测定。结果表明：经电击晕后屠宰,肉羊血液中乳酸含量、皮质醇含量、乳酸脱氢酶活性及肌酸激酶活性显著低于其他2 种方式,肉羊在屠宰过程中应激反应也最小;相比于抹脖子及掏心式屠宰2 组,电击晕组羊肉的蒸煮损失率较低,而嫩度高于抹脖子组,且与掏心组差异不显著,红度值（a*）高于上述2 组,且电击晕组羊肉的硫代巴比妥酸反应物值最低;营养方面,电击晕及掏心式屠宰可提高羊肉中不饱和脂肪酸的含量。因此,从肉羊屠宰食用品质及经济效益等方面比较,电击晕屠宰方式可以减小肉羊应激反应,提高肉羊屠宰企业的经济效益,符合动物福利屠宰要求。     

Influence of muscle type on physicochemical and sensory properties of foal meat

The effect of muscle type on physico-chemical properties and sensory characteristics of foal meat was investigated. Six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and psoas major & minor (PM) from twelve foals slaughtered at 15 months from an extensive production system in freedom regimen were extracted for this study. Regarding chemical composition, intramuscular fat content showed significant differences among muscle where PM presented higher values (0.7%) than the other ones. The heme-iron content also presented significant differences ranging between 1.5 and 2.4 mg/100 g fresh meat. ST was the lightest, while TB and PM presented a more intense redness. The muscles that had a greater capacity to hold water were ST and BF, which presented lower drip loss (2 and 2.2%) and cooking loss (17.3 and 17.2%), respectively. Textural traits established the following scale in response to the tenderness: LD > PM > ST > TB > BF > SM. Finally, sensory analyses revealed that color and texture traits (hardness, juiciness and fibrousness) were significantly influenced by muscle type.     

Colour and texture characteristics in meat of male and female foals

The effect of livestock production system and sex was studied on the colour and on the texture profile of the longissimus dorsi muscle (LD) from 16- and 24-month-old foals aged 4 days. Besides, the effect of ageing time was also studied on the texture profile between 4 and 8 days. Females from the 16-months group were darker than their counterparts and the 4-day aged steaks of the 24-month-old foals were lighter, redder and yellower. LD muscle of the 24-month-old foals was tougher after 4 and 8 days ageing than that of the younger foals besides in the 24-month-old foals the toughness may have been accentuated by lower growth rate prior to slaughter. Ageing improved tenderness but the rate of tenderisation was different according to age. The colour coordinates a^* and b^* could differentiate the 4-day aged steaks of the foal samples according to production system to a higher degree than did the compression or WBSF values being b^* values the most important colour coordinate which could discriminate the origin of the animals.     

畜禽宰后肌肉能量代谢与肉品质研究进展

畜禽宰后肌肉通过糖酵解等能量代谢途径提供ATP满足能量需要,产物乳酸的生成会降低pH。糖酵解的速度和程度影响了pH的下降速度和程度,进而调控肉品色泽、嫩度、持水性、多汁性、风味等品质。本文综述了畜禽宰后肌肉能量代谢的基本路径,论述了腺苷酸激活蛋白激酶对糖酵解的调控机理及其对肉品质的影响,并着重叙述了白肌肉(pale soft and exudative meat,PSE)的预防措施,为在生产过程中肉品质调控提供思路。     

Effects of age and/or weight at slaughter on longissimus dorsi muscle: Biochemical traits and sensory quality in pigs

The effect of increasing either age alone through feed restriction, or both age and weight at slaughter, on the quality of the longissimus dorsi muscle (LM) was investigated. Starting at 83 days of age and 32 kg, 80 pigs were allotted within litter to four experimental groups. All pigs were free of RYR1 mutated gene. Pigs were fed either ad libitum (A100, A130) or restricted 30% (R100, R130) and slaughtered at either 100 kg (A 100, R100) or 130 kg (A130, R130) body weight. Restricting feed intake in order to increase age at the same weight resulted in slower growth, better feed efficiency and increased leanness, whereas increasing age and weight simultaneously elicited slower growth, reduced feed efficiency and fatter carcasses. Intramuscular fat (IMF) and muscle collagen concentration were reduced by restricted feeding. Increase in both age and weight of pigs resulted in lower water, and higher protein and IMF concentrations. Although pigs were free of RYR1 gene, the PSE condition (defined as pH1 ≤ 5.9) developed in 25 carcasses, with a higher incidence in restricted pigs. PSE animals were excluded from the subsequent analysis of meat quality data. Feed restriction resulted in higher drip loss and lower a^* and c^* (saturation index) values. Longer myofibril fragments in muscle of restricted pigs on day 1 post mortem are indicative of slower maturation, while longer fragments on day 4 in heavier pigs, suggest that the extent of post mortem tenderisation could be negatively affected by the elevation of slaughter weight. Feed restriction had no significant effect on meat sensory quality, whereas increase in both age and weight resulted in lower tenderness, chewiness and mouth coating scores. Our results indicate that increasing age at a given body weight, via feed restriction, reduced IMF and collagen concentrations, and the rate of post mortem proteolysis, however, this had no significant impact on pork quality assessed after 4 days of ageing. On the other hand, increasing both age and weight at slaughter could alter pork texture, in spite of elevated IMF concentration.     

不同月龄羊肉原料肉品质与涮食羊肉品质的关系

以6、12、18、24月龄的舍饲巴寒杂交羊为研究对象,每个月龄选择10头胴体质量相近的肉羊(公母各半)进行屠宰,采集后腿肉分析其理化特性、肌纤维特性、涮制出品率与涮食羊肉食用品质。结果表明:除了p H_(24)值、涮食羊肉弹性与涮制出品率外,不同月龄巴寒杂交羊后腿肉理化特性、肌纤维特性、涮食羊肉剪切力和质构、感官评价指标均存在显著差异(P0.05);咀嚼性、硬度与肌节长度呈显著正相关,相关系数为0.618和0.639;弹性与肌纤维密度呈显著正相关,相关系数为0.588;胶原蛋白含量与涮制出品率呈显著负相关,相关系数为-0.458;6月龄羔羊肉感官评价指标色泽、嫩度、风味以及总体可接受性得分均显著优于24月龄(P0.05),羔羊涮食羊肉片更受感官评价人员的喜爱。研究证实低月龄羔羊肉更适宜涮制食用。     

Influence of dietary conjugated linoleic acids (CLA) and age at slaughtering on meat quality and intramuscular collagen in rabbits

To assess the effects of dietary conjugated linoleic acids (CLA) on meat composition and intramuscular collagen (IMC), 144 New Zealand White rabbits, half males half females, 55 days old (1.8 kg LW), were assigned to three weight- and sex- balanced groups and given the following dietary supplements: 0.5% sunflower oil, (C); 0.25% sunflower oil plus 0.25% CLA (T1); and 0.5% CLA (T2). The CLA was prepared from sunflower oil and contained 65% CLA isomers, half cis-9, trans-11 and half trans-10, cis-12. Six males and six females from each group (total 36) were slaughtered at 76, 90 and 104 days of age (corresponding to 2.5, 2.8, and 3.1 kg BW, respectively). The lean fraction was higher and the water content significantly higher in the meat of T2 compared to C and T1 for all ages combined. At the third slaughtering (104 days) the meat fat content was significantly lower in group T2. For all ages combined, IMC content, IMC hydroxylysylpyridinoline (HLP) concentration (index of collagen cross-linking) and IMC maturity (HLP/IMC) were significantly lower in the intermediate supplementation group (T1) compared to C and T2, and were also lower in animals slaughtered at 90 days. CLA supplementation has limited effects on the chemical composition of rabbit meat, with positive effects on meat texture and tenderness after supplementation up to 35 days at 0.25%, and a significant decrease in fat content only at high slaughter weight and high supplementation level (0.5%).     

Meat and fat quality of unweaned lambs as affected by slaughter weight and breed

Sixty-four male lambs of two Southern Spanish breeds, a dairy breed (Grazalema Merino) and a meat breed (Churra Lebrijana), were used to study the effects of slaughter weight and breed on meat traits and intramuscular and subcutaneous fat composition. Lambs were reared following a traditional production system without weaning and slaughtered when live weight reached 12 kg (suckling) or 20 kg (light). Meat from suckling lambs of both breeds had lower fat and myoglobin contents, and was more tender and had higher scores for sustained juiciness in the sensory analysis. Fat from light lambs had lower C12:0 and C14:0 levels than fat from suckling lambs. Grazalema Merino meat had higher fat and ash contents, and its fat had higher conjugated linoleic acid content than Churra Lebrijana meat.     

不同屠宰方式对新疆多浪羊肉品质的影响

以新疆多浪羊为研究对象,对比分析传统屠宰（对照）和3 个不同电压（90、127 V和220 V）击晕屠宰 （分别计作EST 90、EST 127、EST 220）对多浪羊肉品质的影响。结果表明：EST 90处理组成熟过程中pH值下降 速率最快,血液中的皮质醇浓度、肌酸激酶和乳酸脱氢酶活力最高,羊应激反应最剧烈,宰后1、7 d的蒸煮损失率 最高（P＜0.05）;EST 127处理组的持水力最好;电击晕对多浪羊肉嫩度有一定影响,宰后7 d各处理组嫩度显著 改善,而EST 127处理组表现最佳;EST 220处理组放血不充分,且胴体表皮有多处血斑形成;电击晕屠宰对多浪羊 肉色泽无显著影响（P＞0.05）。综合分析实验结果,EST 127处理组持水力与嫩度较优,羊应激反应较小,肉品质 相对较好,因此EST 127处理适合应用于多浪羊的屠宰加工。     

Effect of stunning conditions on occurence of PSE defects in hams of rn+/RN(-) pigs

Pigs of the same genetic type at the RN and HAL loci, i.e. rn⁺RN⁻/NN were reared in similar conditions of feeding and housing. They were slaughtered in two abattoirs (referred to as A1 and A2) using a mixture of air (30%) and CO₂ (70%), at a rate of 300 pigs per hour per slaughterline. One hundred and thirty-two pigs from 11 farms were slaughtered in A1 using a corusinga restrainer and 127 pigs from 5 farms were slaughtered in A2 with the backloading technique. pH at 40 min, 2.5 h and 24 h after slaughter and colour (L*, a*, b*) at 24 h after slaughter were measured in the semimembranosus muscle. Meat quality of the ham was scored as follows: 1, no PSE-zone; 2, doubtful; 3, PSE-zones in the semimembranosus and sometimes on the internal flexor muscles; 4, PSE-zones in all the flexor muscles. The muscle pH value was higher in A2 than in A1 at 40 min post mortem (P<0.01), but not at 2.5 and 24 h. L* (P<0.001) and b* (P<0.05) were higher in A1 than in A2. There was a remarkable difference in meat quality scores, with 50% of the hams scoring 3 or 4 in A1, vs 13% in A2. Lairage time before slaughter affected (P<0.01) the pH value at 2.5 h (5.69 vs 5.93). The values of pH1 and pH2.5 decreased with increasing the meat quality score. The values of L* and b* increased markedly with the score. The results of the present study indicate that the method of bringing the slaughter pigs to the stunning device affects the frequency and importance of PSE meat in the ham. The automated driving of groups of animals to the stunning machine combined with the backloading of a nacelle, compared to a traditional system driving pigs in single file using electrical goads and a restrainer was beneficial with respect to both meat quality and animal welfare.     

The effect of growth rate and ultimate pH on meat quality of lambs

Entire male Romney lambs (n = 60) were grown slowly (67 g/day) and slaughtered at 14 months of age at an anticipated carcass weight of 18 kg. Another group of ram lambs (n = 15) from the same genetic background (born 7 months later) were grown rapidly (162 g/day) for 7 months and slaughtered at the same time and at a similar carcass weight. Preslaughter shearing (20 days prior to slaughter) and swim washing (3 times) were variously imposed upon the 14-month old lambs to give them a graded preslaughter stress. The lambs were head-only electrically stunned and slaughtered. Dressed carcasses were electrically stimulated at 20 min post mortem for 90 s at 14·3 pulses/s, 1·8-2 A and 1130 V peak, then held at 12°C for 2 h and frozen so that the deep leg reached -4°C in 12 h. The ultimate pH was measured for the longissimus dorsi, and loin samples were assessed by tenderometer and a sensory panel. The groups with the greatest stresses imposed had the highest ultimate pH. The most tender meat came either from carcasses with an ultimate high pH greater than 6·3 or from young lambs with an ultimate pH from 5·5-5·7. While 7-month old lambs were slightly more tender than the 14-month old lambs of iso pH, the 14-month old lambs of high pH were the most tender. This suggests that age-related connective tissue effects were minimal for the loin. The shear force values and taste panel tenderness scores were linearly related. When the shear force and panellists' tenderness scores were expressed in relation to ultimate pH, there was a decreased acceptance of meat with a moderate ultimate pH between 5·8 and 6·0. Panel texture assessments showed a less clearly defined, but statistically significant decrease in acceptance at pH 5·8-6·0. Other sensory attributes of flavour, juiciness and aroma were uniform across the whole ultimate pH spectrum.     

Carcass composition and yield of Alaskan reindeer (Rangifer tarandus tarandus) steers and effects of electrical stimulation applied during field slaughter on meat quality

Twenty six adult reindeer steers (>3 years old) were used in a study to evaluate the effect of electrical stimulation (ES) on the quality of hot-boned, rapidly frozen shoulder meat and of the striploin (M. longissimus, LD) from carcasses held at +3°C for 48h. Carcass yield and composition was determined from the left carcass half from which the shoulder meat was not removed. The shoulder meat was processed frozen into cubed, sliced or ground products. Proximate composition of the LD, meat color and water-holding capacity were very similar for the ES (n=15) and non-electrical stimulation (NES; n=11) groups. Ultimate pH and shear force values were significantly lower in the ES meat (LD), however a trained sensory panel could not detect differences between the two groups in any of the measured sensory attributes. Consumer preference tests demonstrated that ES increased tenderness in the cubed and sliced products made from field slaughtered reindeer shoulder meat. ES in combination with hot boning and processing of boneless frozen meat can be used in field slaughter systems for reindeer to improve meat quality and to increase the potential value of the carcass.