Effect of fast freezing then thaw‐aging on meat quality attributes of lamb M. longissimus lumborum

The objective of this study was to determine the effect of two different freezing rate then thaw‐aging regimens on the quality attributes of lamb loins. The loins were randomly allocated to one of five different freezing/thawing/aging regimes: fast‐(FF1A0) and slow‐(SF1A0) frozen only; fast‐(FF1A2) and slow‐(SF1A2) frozen then thaw‐aged for 14 days; aged for 14 days never frozen (A2). FF1A2 samples had a significantly higher water‐holding capacity compared to the slow frozen regardless of further aging periods. FF1A2 samples had lower (p < 0.05) shear force values than A2 and higher (p < 0.05) water‐holding capacity compared to the SF1A2. Fast freezing resulted in more intracellular cryo‐damage, whereas slow freezing resulted in extracellular cryo‐damage. FF1A0 and SF1A0 samples had lower (p < 0.05) myofibrillar proteins degradation. This study demonstrated that fast freezing then thaw‐aging can result in an improved water‐holding capacity and tenderness through the minimization of extracellular ice crystal formation, reduction in purge and drip losses, and improved proteolysis in thawed lamb.     

Effect of a low‐voltage electrical stimulation on yak meat tenderness during postmortem aging

This study evaluates the effect of a low‐voltage electrical stimulation (ES) on the tenderness of yak longissimus muscle (LM). Samples from 16 yak bulls were divided into four treatment groups: normal chilling (NC), ES and chilling (ES & C) for 72 s (ES &C 72 s), ES & C for 90 s (ES & C 90 s), and ES & C for 108 s (ES & C 108 s). The temperature, the pH, the glycogen content, the Warner‐Bratzler shear force (WBSF), the myofibril fragmentation index (MFI), and the muscle ultrastructure were determined during the course of postmortem aging. ES caused a rapid decrease in the pH to form a high‐temperature and low‐pH environment. The glycogen content gradually decreased with aging. The WBSF value of the ES & C groups was significantly lower than for the NC group (p < .05). The MFI values of ES & C groups after 24 hr postmortem aging were significantly higher than for the NC group. We concluded that ES improved yak meat tenderness during postmortem aging and that the different duration time by ES indicated different effects, and its affect was remarkable in the ES & C 90 s.     

The effect of high pre‐slaughter environmental temperature on meat quality traits of Italian autochthonous pig Suino Nero Lucano

The aim of the present study was to evaluate the effect of high pre‐slaughter environmental temperature on meat (Longissimus lumborum muscle) quality traits of Italian autochthonous pigs Suino Nero Lucano (SNL). High pre‐slaughter environmental temperature influenced the meat quality of autochthonous pigs. In particular, the meat from SNL pigs exposed to heat stress (H) showed significantly lower pH values at 24 and 48 hr post mortem, haem iron content and redness (a*) value, and a significantly higher shear force, drip loss and lightness (L*) values, compared to meat from SNL pigs reared under comfortable environmental temperature (C). Moreover, H meat showed a significant reduction of vitamin A, vitamin E, creatine and carnosine content, compared to C meat. Despite this, no pale‐soft‐exudative pork was found in our study, and no significant difference was detected between two studied groups for intramuscular fat and protein content of meat. In addition, despite the meat from SNL pigs exposed to heat stress has suffered a qualitative decrease, it showed a good endogenous antioxidants content.     

Effects of transportation during the hot season,breed and electrical stimulation on histochemical and meat quality characteristics of goat longissimus muscle

The effects of transportation and electrical stimulation (90 V) on physiological, histochemical and meat quality characteristics of two breeds of Omani goats were assessed. Twenty 1‐year‐old male goats from each breed (Batina and Dhofari) were divided into two groups: 3 h transported during the hot season (42°C day time temperature) and non‐transported. Animals were blood‐sampled before loading and prior to slaughter. Electrical stimulation was applied 20 min postmortem to 50% randomly selected carcasses of both breeds. Temperature and pH decline of the Longissimus was monitored. Ultimate pH, shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and colour were measured from samples of Longissimus dorsi muscles. Electrical stimulation and transportation had a significant effect on most biochemical and meat quality characteristics of Longissimus dorsi. The transported goats had higher plasma cortisol (P < 0.01), adrenaline, nor‐adrenaline and dopamine concentrations (P < 0.05) than non‐transported goats. Electrical stimulation resulted in a significantly (P < 0.05) more rapid muscle pH fall during the first 12 h after slaughter. Muscles from electrically‐stimulated carcasses had significantly (P < 0.05) longer sarcomeres, lower shear force value, a lighter colour (higher L* value), higher expressed juice and myofibrillar fragmentation index than those from non‐stimulated ones. Meat from transported goats had significantly higher pH, expressed juice and shear force, but contained significantly lower sarcomere length and L* values than non‐transported goats. The proportion of the myosin ATPase staining did not change as a function of stimulation, transportation or breed. These results indicated that subjecting goats to transportation for 3 h under high ambient temperatures can generate major physiological and muscle metabolism responses. Electrical stimulation improved quality characteristics of meat from both groups. This indicates that electrical stimulation may reduce detrimental effects of transportation on meat quality of Omani goats.     

全混合日粮营养水平对热应激肉牛生长性能、瘤胃形态学及肉质的影响

文章旨在评估热应激条件下通过调整全混合日粮营养水平来改善肉牛生长性能、瘤胃形态学及肉品质.试验将6月龄大、平均体重为(85.08±2.31)kg的64头荷斯坦肉牛随机分为2组,每组8个重复,每组32头.从6月龄开始试验,两组肉牛分别饲喂粗蛋白质水平为16.0％和12.0％的全混合日粮,持续到15月龄.整个试验期间外界环...     

Effects of temperature and temperature‐humidity index on the reproductive performance of sows during summer months under a temperate climate

Heat stress is known to influence sow reproduction, but it is unknown to which extent under temperate climates. Therefore, the impact of temperature and temperature‐humidity index (THI) on the reproductive performance of sows during summer months from 2009 to 2011 were studied. Reproductive parameters of 22 264 inseminations and 21 610 resulting farrowings of 22 German commercial farms were analyzed. Climatic records were available from the nearest weather station. Effects of temperature and THI at different periods of the reproductive cycle were estimated from May to September where temperatures were expected to influence climatic conditions indoors. High temperatures and THI values 5 days pre‐ and 14 days post‐breeding reduced litter size by 0.01 to 0.03 piglets (P < 0.05). Prior to farrowing, the number of liveborn piglets was reduced (P < 0.05) and of stillborns increased with rising climatic variables (P < 0.001). On the day of farrowing, reduced numbers of weaned piglets were observed when temperature and THI values were elevated (P < 0.05), but pre‐weaning mortality was not influenced (P > 0.05). In conclusion, even under temperate conditions adverse effects of climatic variables on the reproductive performance of sows are present. Thereby, the number of liveborn piglets can be considered as the most sensitive parameter to heat stress. Considering the impact of climate change and predicted heat waves, strategies to mitigate the impact of heat stress are necessary.     

中草药提取物对热应激肉牛生长性能、养分消化、瘤胃发酵及肉品质的影响

文章旨在研究中草药提取物对热应激肉牛生长性能、养分消化、瘤胃发酵和肉品质的影响.试验将48头体重无统计学差异的肉牛随机分为两组,每组24头,每组12个重复,每个重复2头牛.对照组与处理组肉牛分别饲喂全混合日粮+0和120 mg/kg中草药提取物,试验为期8周,饲养环境温度为(32±1.5)℃.结果:与对照组相比,中草药...     

Effects of pre‐slaughter showering and ventilation on stress,meat quality and metabolite concentrations of broilers in summer

Effects of pre‐slaughter showering and ventilation on stress, meat quality and energy metabolism of broilers in summer were investigated. After transport, 84 Arbor Acres broilers were randomly divided into four treatment groups: (i) control group without ventilation and showering (C); (ii) 10 min ventilation without showering (VWS); (iii) 10 min showering without ventilation (SWV); (iv) 5 min showering and then 5 min ventilation (SV). Compared with the control group, plasma lactate dehydrogenase and creatine kinase activities in the other three treatment groups were (P < 0.05) lower; however, the plasma glucose level did not show any significant changes among all the groups. The breast meat in the SV group had significantly (P < 0.05) higher pH_u, glycogen content, lower L*, ΔpH, drip loss, cook loss, R‐value and lactate content than the control group; however, there was no significant difference in shear force values among all the groups. In conclusion, this study indicated broilers in the SV group showed a lower stress level and greater meat quality, which suggest that showering and ventilation after transportation may be a good measure to relieve stress caused by transport under high temperature and improve the meat quality of broilers.     

Influence of rice whole‐crop silage diet on growth performance,carcass and meat characteristics and muscle‐related gene expression in Japanese Black steers

The present study investigated the influence of a diet largely comprising rice whole‐crop silage (rWCS) on growth performance, carcass and meat characteristics, and expression of genes involved in muscle growth of Japanese Black steers. Steers were randomly separated into rWCS‐fed (rWCS ad libitum and restricted feeding of concentrate) and concentrate‐fed groups. Total digestible nutrient intake and daily gain (DG) decreased in rWCS‐fed steers in comparison with concentrate‐fed steers, whereas dressed carcass weight and final body weight did not significantly differ between the groups. Decreases in drip loss in the muscle of rWCS‐fed steers may be caused by α‐tocopherol and β‐carotene in muscle. Feeding large amounts of rWCS to steers may maintain quantitative productivity of beef steers equally to a concentrate‐based diet, and improve the qualitative productivity. Results of gene expression suggest that activation of skeletal muscle growth in rWCS‐fed steers may occur at the late fattening period owing to a decrease in myostatin and increase in myosin heavy chain gene expression. Preadipocyte factor‐1 and myostatin genes may be strongly involved in the control of lipid accumulation. This rearing system would allow beef production to switch to rWCS‐based diets from concentrate‐based diets.     

Dose response of rumen‐protected conjugated linoleic acid supplementation to fattening bulls and heifers on growth,and carcass and meat quality

We investigated the influence of rumen‐protected conjugated linoleic acid (rpCLA) on growth performances, and carcass and meat quality traits in beef. Twenty‐four young bulls and 30 heifers obtained from double‐muscled beef sires and dairy cows were fed a low‐protein ration (110 g/kg DM of crude protein) supplemented with 0, 8 or 80 g/d of a commercial rpCLA product. The animals were monthly weighed and scored for body muscularity and fatness. Blood samples were collected after 140 days on feed. Animals were slaughtered when they reached average in vivo fatness scores of around 2.5 (heifers) and 2.0 (bulls) points respectively. At slaughter, carcasses, various organs and parts of the gastrointestinal tract were weighed; the 5th rib was dissected and its tissue and muscle chemical composition was determined. The rpCLA had little influence on growth performance but decreased the blood urea content by 28% (p < 0.01). The rpCLA × sex interactions for daily gain (p < 0.05), conformation scores (p < 0.01), and blood creatinine content (p < 0.05) suggest that males were more responsive to rpCLA than females when fed a low‐protein ration, probably because of the metabolic protein‐sparing effect of CLA. Only slight differences were observed in carcass weight and quality at slaughter. The results indicate that the response of beef cattle to rpCLA is dependent on sex or on their propensity for lean and fat accretion. It is also possible that counteracting feedback mechanisms compensate for the influence of rpCLA administration over the course of growth.     

Improving effects of dietary rumen protected γ‐aminobutyric acid additive on apparent nutrient digestibility,growth performance and health status in heat‐stressed beef cattle

This study was aimed to investigate the effects of rumen‐protected γ‐aminobutyric acid (RP‐GABA) on apparent nutrient digestibility, growth performance and health status in heat stressed beef cattle. Fifty Jinjiang Yellow cattle were randomly assigned to 5 treatments (10 animals/treatment). Treatments 1 to 5 were basal diets affixed with 0 (control), 8, 16, 24 and 32 mg of RP‐GABA/kg of body weight (BW) respectively. The trial lasted 45 days. Apparent digestibility of crude protein (CP), crude fiber (CF) and calcium (Ca) quadratically increased with increasing RP‐GABA (p < .01), while apparent digestibility of phosphorus (P) tended to quadratically increase (p = .09). Dietary supplementation with increasing RP‐GABA linearly increased DM digestibility and average daily gain (ADG) (p < .01), whereas the feed to gain (F:G) ratio linearly decreased with increasing RP‐GABA (p < .01). The average daily feed intake (ADFI) value tended to linearly increase with RP‐GABA supplementation (p = .08). Total protein (TP), blood urea nitrogen (BUN) and malondialdehyde (MDA) levels quadratically decreased (p < .01) with increasing RP‐GABA, however albumin (ALB), glucose (GLU), superoxide dismutase (SOD), triiodothyronine (T3) and thyroxine (T4) levels quadratically increased (p ≤ .01). In conclusion, the present results indicated that dietary supplementation with RP‐GABA led to improved nutrient digestibility, growth performance and antioxidant status in heat stressed beef cattle.     

Effects of ensiling cereal grains (barley,wheat, triticale and rye) on total and pre‐caecal digestibility of proximate nutrients and amino acids in pigs

Inclemency of weather frequently causes critical water contents in cereal grains above 15%. Ensiling in pre‐mature condition may be an alternative to other techniques of preservation. Aim of this study was to compare apparent total tract digestibility (D_t; barley, wheat, triticale, rye) of proximate nutrients and pre‐caecal digestibility (D_pc; barley, wheat) of amino acids (AA), respectively, from cereal grains in ensiled and almost dry condition. Moistly harvested cereal grains (67–73% dry matter) were milled through a 4‐mm sieve and ensiled with lactic acid bacteria (LAB, 3 × 10⁵ colony forming units/g Lactobacillus plantarum DSMZ 8862 and 8866). To investigate D_t, two trials were conducted with six Mini‐Lewe pigs and four German Landrace pigs, respectively. D_pc of AA was determined using four German Landrace pigs with ileo‐rectal anastomosis. D_t of proximate nutrients did not differ between cereal grains and their silages, except for ether extract, which was more digestible in ensiled than dry wheat, triticale and rye (p < 0.05). Lysine content was lower in ensiled than dry barley and wheat. In barley, ensiling was accompanied by reduced D_pc of lysine and histidine (p < 0.05). In wheat, ensiling increased D_pc of lysine, methionine, threonine and leucin (p < 0.05). Ensiling of pre‐mature cereal grains with LAB can serve as a reasonable storage alternative. However, as limited data are yet available, further research is required to understand completely the impact of ensiling on nutritional value as indicated, for example, by the lysine content and the D_pc of certain AA.     

Effects of different rearing systems on meat production traits and meat fiber microstructure of Beijing‐you chicken

Beijing‐you is a Chinese local chicken which is raised for both meat and eggs. In the present study, we detected the effects of different rearing systems on growth, slaughtering performances and meat quality of Beijing‐you chickens at 26–40 weeks of age. Six hundred Beijing‐you hens were randomly allocated into two groups at 16 weeks of age and raised in free range or battery cage systems. The body weight, slaughtering performance and meat quality were measured for each group at the ages of 26, 30, 35 and 40 weeks. Some of the traits were dramatically influenced by the two systems, although most of them did not show significant changes. For the meat fiber microstructure, we found that the diameter of thigh and breast muscle fiber in the free range group were significantly increased than in the cage group (P < 0.05) at 26 weeks of age. The ratio of fast muscle fiber in thigh muscle samples of the free range group was significantly reduced compared to that of cage group at both 35 (P < 0.01) and 40 (P < 0.01) weeks of age, indicating that the free range system could promote the transforming of fast muscle fiber to slow muscle fiber.     

Effects of water‐misting sprays with forced ventilation on post mortem glycolysis,AMP‐activated protein kinase and meat quality of broilers after transport during summer

Effects of water‐misting sprays with forced ventilation on post mortem glycolysis, adenosine monophosphate‐activated protein kinase (AMPK) and meat quality of broilers after transport during summer were investigated in the present paper. A total of 105 mixed‐sex Arbor Acres broilers were divided into three treatment groups: (i) 45 min transport without rest (T); (ii) 45 min transport with 1 h rest (TR); and (iii) 45 min transport with 15 min water‐misting sprays with forced ventilation and 45 min rest (TWFR). Each treatment consisted of five replicates with seven birds each. The results indicated that the water‐misting sprays with forced ventilation could mitigate the stress caused by transport under high temperature conditions during summer, which reduced the energy depletion in post mortem Pectoralis major (PM) muscle. This resulted in a higher energy status compared to the T group, which would decrease the expression of phosphorylation of AMPK (p‐AMPK). Furthermore, decreased the expression of p‐AMPK then slowed down the rate of glycolysis in post mortem PM muscle during the early post mortem period, which in turn lessened the negative effects caused by transport on meat quality. In conclusion, water‐misting sprays with forced ventilation may be a better method to control the incidence of the pale, soft and exudative meat in broilers.     

Effects of supplementation with green tea by‐products on growth performance,meat quality,blood metabolites and immune cell proliferation in goats

Forty‐eight castrated male goats were used to determine the effects of feeding green tea by‐products (GTB) on growth performance, meat quality, blood metabolites and immune cell proliferation. Experimental treatments consisted of basal diets supplemented with four levels of GTB (0%, 0.5%, 1.0% or 2.0%). Four replicate pens were assigned to each treatment with three goats per replicate. Increasing dietary GTB tended to linearly increase the overall average weight gain and feed intake (p = 0.09). Water holding capacity, pH and sensory attributes of meat were not affected by GTB supplementation, while cooking loss was reduced both linearly and quadratically (p < 0.01). The redness (linear; p = 0.02, quadratic; p < 0.01) and yellowness (quadratic; p < 0.01) values of goat meat were improved by GTB supplementation. Increasing dietary GTB quadratically increased protein and decreased crude fat (p < 0.05), while linearly decreased cholesterol (p = 0.03) content of goat meat. The proportions of monounsaturated fatty acid, polyunsaturated fatty acid (PUFA) and n‐6 PUFA increased linearly (p < 0.01) and n‐3 PUFA increased quadratically (p < 0.05) as GTB increased in diets. Increasing dietary GTB linearly increased the PUFA/SFA (saturated fatty acid) and tended to linearly and quadratically increase (p ≤ 0.10) the n‐6/n‐3 ratio. The thiobarbituric acid‐reactive substances values of meat were lower in the 2.0% GTB‐supplemented group in all storage periods (p < 0.05). Dietary GTB linearly decreased plasma glucose and cholesterol (p < 0.01) and quadratically decreased urea nitrogen concentrations (p = 0.001). The growth of spleen cells incubated in concanavalin A and lipopolysaccharides medium increased significantly (p < 0.05) in response to GTB supplementation. Our results suggest that GTB may positively affect the growth performance, meat quality, blood metabolites and immune cell proliferation when supplemented as a feed additive in goat diet.     

Effects of nutritional level of concentrate‐based diets on meat quality and expression levels of genes related to meat quality in Hainan black goats

The present study investigated the effects of the nutritional levels of diets on meat quality and related gene expression in Hainan black goat. Twenty‐four goats were divided into six dietary treatments and were fed a concentrate‐based diet with two levels of crude protein (CP) (15% or 17%) and three levels of digestive energy (DE) (11.72, 12.55 or 13.39 MJ/kg DM) for 90 days. Goats fed the concentrate‐based diet with 17% CP had significantly (P < 0.05) higher average daily gains (ADG) and better feed conversion rates (FCR). The pH _24h value tended to decrease (P < 0.05) with increasing DE levels. The tenderness of Longissimus dorsi muscle (LD) and Semimembranosus muscle (SM) reduced with increasing CP levels (P < 0.05). With increasing DE levels, tenderness was increased (P < 0.05). The heart fatty acid‐binding protein (H‐FABP) mRNA expression levels in LD and SM increased with increasing DE levels (P < 0.05), but decreased with increasing CP levels (P < 0.05). The calpastatin (CAST) and μ‐calpain mRNA expressions levels in LD and SM were affected significantly (P < 0.05) by CP and DE levels in the diet. Therefore, the nutritional levels of diets affect meat quality and expression levels of genes associated with meat quality in Hainan black goats.     

Effects of calcium soap of rice bran oil fatty acids supplementation alone and with DL‐α‐tocopherol acetate in lamb diets on performance,digestibility, ruminal parameters and meat quality

Thirty‐six Malpura lambs (28 day old and 6.7 ± 0.25 kg BW) were distributed equally in three groups having six males and six female. They were ad libitum fed individually three different experimental diets containing calcium soap of fatty acids (CA‐FA) at 0 (T₁) and 40 (T₂ and T₃) g/kg concentrate up to six months of age. Animals in T₃ were supplemented additionally with 40 mg DL‐α‐tocopherol acetate/kg of concentrate. The roughage moiety included ad libitum dry Prosopis cineraria and fresh Azadirachata indica leaves. All the lambs were allowed to suckle from their dam up to weaning (90 day of age). Supplementation of Ca‐FA improved weight gain and feed conversion ratio during both pre‐ (28–90 days) and post‐weaning (91–180 days) phases; however, no effect of DL‐α‐tocopherol was observed. Metabolic parameters during post‐weaning phase revealed non‐significant effect on digestibility but improved nitrogen balance in the test groups. The effect on biochemical attributes did not show any significant alteration in ruminal parameters, blood biochemicals and urinary purine derivatives. Carcass traits revealed higher (p < 0.05) dressing yield and loin eye area with Ca‐FA supplementation. The value of thiobarbituric reactive substances for nuggets prepared from frozen carcasses revealed significant (p < 0.05) reduction in T₃ compared to the other dietary groups. Fatty acid profile of adipose tissue revealed higher (p < 0.001) 9‐octadecanoic, 9‐12‐octadecadienoic, polyunsaturated fatty acids (PUFA), higher ratio of PUFA/saturated fatty acids (SFA), ω‐6/ω‐3 and lower SFA in Ca‐FA‐supplemented groups. It is concluded that supplementation of 40 g/kg calcium soap prepared from industrial grade rice bran oil in lamb ration provided additional energy intake, improved N utilization, gain and feed conversion ratio besides improving dressing yield and meat quality with CLA enriched fatty acid profile. DL‐α‐tocopherol acetate when supplemented at 40 mg/kg feed reduced lipid oxidation of meat products thus improving its keeping quality.