钙和维生素D3对黄羽肉鸡肌肉嫩度的影响及机理

本试验研究了宰前2周添加钙和维生素D3对黄羽肉鸡肌肉嫩度的影响.试验采用2×3因子随机试验设计,选用1 440只43日龄的黄羽肉鸡(母鸡),随机分为9组,每组4个重复,每个重复40只鸡.预饲1周后在基础日粮(含钙0.8%、维生素D3 1 000 IU/kg)中添加钙与维生素D3水平分别为:钙,0.0%、0.4%、0.8%;维生素D3,0、1 000、2 000 IU/kg.鸡饲养至63日龄结束.结果表明,在黄羽肉鸡宰前2周添加钙与维生素D3对黄羽肉鸡的生长性能无显著影响(P＞0.05).添加维生素D3对黄羽肉鸡肌肉嫩度无显著影响(P＞0.05),添加0.4%钙显著提高黄羽肉鸡肌肉嫩度(P＜0.05),添加维生素D3能协同钙提高肌肉嫩度,但钙的添加剂量超过0.4%时维生素D3协同作用效果下降.单独添加维生素D3对Ca-ATP酶活性及肌钙蛋白降解度无显著影响(P＞0.05);添加0.4%的钙,Ca-ATP酶活性趋于提高,肌钙蛋白降解度趋于降低,钙蛋白酶抑制蛋白的基因表达显著提高(P＜0.05).由此可知,黄羽肉鸡饲料中添加0.4%钙能提高肌肉嫩度,单独添加维生素D3不能改善肌肉嫩度但是可以协同钙提高肌肉嫩度.     

补饲维生素D3对育肥猪血钙与肌肉钙含量的影响

本试验旨在研究宰前短期补饲维生素D3对育肥猪血钙和肌肉钙舍量的影响.将20头体重85 kg左右的杜长大三元杂交猪随机分为5组,每组4头.试验设维生素D3的补饲量(2.5×105 Iu/d或5×105IU/d)和补饲时间(5 d或10 d)两个因素.通过对血清钙水平和内中钙含量的测定采评价补饲维生素D3对育肥猪血钙和肌肉钙含量的影响.研究结果表明:补饲维生素D3能提高育肥猪的血清钙含量和肌肉钙的含量(P＜0.05),促进钙的沉积.     

维生素D_3对家畜肉质的影响

近年的研究发现,补饲维生素D3能够提高牛肉的嫩度,还能改善猪肉的色泽。本文阐述了维生素D3对家畜肉质的影响及研究现状,并对维生素D3改善家畜肉质的作用途径进行了分析。     

维生素D3对畜禽肌肉品质的影响及其研究进展

维生素D，又名胆钙化醇，是维生素D的天然存在形式之一。对于维生素D，的研究主要集中在对钙磷代谢的影响及其预防治疗佝偻病方面。最近国外有研究报道，维生素D，有改善肌肉嫩度及其他肉质的作用，本文就维生素D，就对肌肉品质的作用效果及研究现状进行综述，并对维生素D，改善肌肉嫩度的作用机制进行分析。     

钙和维生素D3对肉仔鸡肉品质和血液生化指标的影响

本试验旨在研究饲粮中添加高水平的钙和维生素D3对AA肉仔鸡肉品质和血液生化指标的影响。试验采用2×2完全随机因子设计,选用240只21日龄AA肉仔鸡,随机分成4个处理,每个处理6个重复,每个重复10只。试验期为28 d。玉米-豆粕型基础日粮中含钙0.90%、维生素D3 750 IU/kg,日粮中共设两个钙水平(0.9%,1.15%)和两个维生素D3水平(750、5000 IU/kg)。结果表明:(1)在AA肉仔鸡饲粮中单独添加1.15%的钙对肌肉嫩度影响显著(P<0.05),5000 IU/kg维生素D3对肌肉嫩度影响不显著(P>0.05),同时添加钙和维生素D3的互作效应对肌肉嫩度影响显著(P<0.05);(2)1.15%的钙显著降低胆固醇、甘油三酯、低密度脂蛋白的含量(P<0.05),显著升高了高密度脂蛋白的含量(P<0.05);(3)单独添加5000 IU/kg维生素D3显著降低了低密度脂蛋白的含量(P<0.05)。以上研究结果表明,玉米-豆粕型基础日粮中长期添加1.15%钙和5000IU/kg维生素D3能够减小肌肉剪切力,降低血液中总胆固醇和甘油三酯的含量,从而提高肉品质。     

饲粮钙和维生素D3水平对肉仔鸡生长性能、屠宰性能和肉品质的影响

本试验旨在研究饲粮钙和维生素D3水平对肉仔鸡生长性能、屠宰性能和肉品质的影响.试验采用2×2完全随机设计,选用21日龄爱拔益加肉仔鸡240只,随机分成4个处理,每个处理6个重复,每个重复10只鸡.饲养时间为28 d.试验以玉米-豆粕型饲粮为基础饲粮,共设2个钙水平(0.90%和1.15%)和2个维生素D3水平(750和5 000 IU/kg),组成4种试验饲粮.结果表明:1)饲喂含有1.15%钙和5 000 IU/kg维生素D3的饲粮21 d对生长性能影响不显著(P>0.05),饲喂28 d对生长性能影响显著(P<0.05);2)1.15%的钙对腹脂率影响显著(P<0.05);3)1.15%的钙对肌肉剪切力影响极显著(P<0.01),5 000 IU/kg维生素D3对肌肉剪切力影响不显著(P>0.05),钙和维生素D3的互作效应对肌肉剪切力影响显著(P<0.05).以上研究结果表明,长期饲喂含有1.15%钙和5 000 IU/kg维生素D3的饲粮将会降低肉仔鸡生长性能;1.15%的钙能降低肉仔鸡的腹脂率,减小肌肉剪切力,从而提高肉品质.     

维生素D3对畜禽肌肉品质的影响及其研究进展

维生素D3又名胆钙化醇,是维生素D的天然存在形式之一。对于维生素D3的研究主要集中在对钙、磷代谢的影响及其防治佝偻病方面。最近国外有研究报道,维生素D3有改善肌肉嫩度及其它肉质的作用,本文就维生素D3对肌肉品质的作用效果及研究现状进行综述,并对维生素D3改善肌肉嫩度的作     

维生素D3对畜禽肉质的影响及其研究进展

本文系统地阐述了VD3对畜禽肉质的影响及其研究现状,并对VD3改善肌肉嫩度的作用机理进行深入的分析。     

如何有效平衡:日粮中被低估的钙含量

钙对骨骼完整性、肌肉收缩等机体功能具有重要的作用，但过量的日粮钙不仅会占用配方的宝贵空间，还会对其他营养物质的消化率和饲用酶的功效产生不利影响。日粮中添加天然来源的生物活性形式维生素D3可促进低矿物质日粮中的钙吸收，不影响钙参与的生理功能。     

维生素D3与钙磷代谢及免疫调控的关系

维生素D3作为一种生物学作用广泛的维生素,对于动物维持健康和充分发挥生产性能至关重要。笔者着重从作用机理及其所影响的生理功能两个方面,系统总结了维生素D3对钙磷平衡、免疫反应及慢性疾病的影响,对提升生产实际中维生素D3的应用水平,具有一定的指导和启发作用。     

畜禽肌肉品质遗传的研究进展

肌肉品质是人们对多种肉质性状的综合评价，肉质主要受遗传因素的影响。为了探明肉质的遗传规律，国内外对肉质主要进行了以下几方面的研究：（１） 肉质性状遗传参数估计；（２） 肌肉品质的相关遗传；（３） 影响肉质的主基因；（４） 与肉质性状连锁的 Ｑ Ｔ Ｌ 的测定。     

Effects of menhaden oil and flaxseed in broiler diets on sensory quality and lipid composition of poultry meat

1. Three hundred and thirty 1-d-old male broiler chicks from a commercial strain were allocated to 11 dietary treatments comprising combinations of flaxseed at 100 g/kg and menhaden oil (MO) at 7.5 or 15 g/kg. Birds were given the experimental diets 7 or 14 d prior to slaughter. Carcase omega-3 fatty acid profiles and sensory evaluations of different cooked meat portions were carried out. 2. Linolenic acid was preferentially deposited in dark meat and long chain omega-3 fatty acids in white meat. Breast meat sensory quality was not affected in birds given 100 g/kg flaxseed for 14 d (treatment 3), 7.5 g/kg MO for 14 d (treatment 5) or 100 g/kg flaxseed +0.75 g/kg MO for 7 d (treatment 6). In contrast, thigh meat sensory quality decreased in treatments 5 and 6. 3. Feeding flaxseed and MO to birds for just 7 d prior to slaughter resulted in significant omega-3 meat enrichment depending on their dietary concentrations. The linolenic acid and long chain omega-3 fatty acids showed preferential deposition in dark and white meat, respectively, which may affect the sensory quality of various portions differently.     

黄秋葵对肉兔生产性能、肉品质和血清生化指标的影响

为研究在饲料中添加不同量的黄秋葵对肉兔生产性能、脏器指数和血清生化指标的影响,试验选用35日龄健康新西兰肉兔120只,随机分成5组,每组3个重复,每个重复8只,预试期7 d,正试期28 d,试验Ⅰ、Ⅱ、Ⅲ、Ⅳ组分别在基础日粮中添加1%、2%、3%和4%黄秋葵粉。结果表明：与对照组相比,试验Ⅰ、Ⅱ、Ⅲ组滴水损失率分别降低16.83%、15.63%和20.19%,差异显著（P < 0.05）|试验Ⅱ、Ⅲ组肉兔的期末重分别增加6.91%、8.81%,平均日增重分别增加16.91%、20.61%,肉品质的红度分别升高50%、56.74%,血清总蛋白分别升高12.44%、23.69%,白蛋白分别升高9.39%、22.91%,均差异显著（P < 0.05）|与对照组相比,试验Ⅱ、Ⅲ组料重比分别下降12.57%、15.64%,肉品的黄度分别降低20.22%、27.22%,血清甘油三脂分别降低9.87%、17.11%,均差异显著（P < 0.05）|与对照组相比,试验Ⅲ组兔肉的剪切力降低16.06%,熟肉率提高12.14%,血清尿素氮下降9.50%,均差异显著（P < 0.05）|各组肉兔的平均采食量、兔肉的亮度、血清葡萄糖、总胆固醇、谷丙转氨酶、谷草转氨酶及碱性磷酸酶活性均无显著差异（P > 0.05）。因此,肉兔饲料中黄秋葵的适宜添加量为3%。 [关键词] 黄秋葵|肉兔|生产性能|肉品质|血清生化指标     

Functionality of Poultry Meat

Functional foods are foods enriched with single ingredients, which influence 1 or more functions of the consumer in a favorable way, exceeding the effects of normal adequate nutrition. Consumers can expect health benefits from these products. The production of functional poultry meat is a promising future perspective, although the market share of such products will be small. The objective of the present paper was to summarize some examples of functional poultry meat. Substances of interest for this purpose are fatty acids and antioxidants. Enrichment of poultry meat with these health-promoting substances is not really a new approach, but there exists a potential for meeting the recommended daily intake for humans despite a probable negative effect on product quality. In the past, many papers were published showing that poultry meat can be enriched with conjugated linoleic acid, omega-3 fatty acids, and Se in such a way that 100 g of enriched tissue meets 3 to 11, 70 to 130, and 60% of the recommended daily intake for humans, respectively. However, the occurrence of tough meat (conjugated linoleic acid) and an increased liability to oxidation (omega-3 fatty acids) may impair the use of functional poultry meat. More research is needed, both on these negative effects on human requirements for these substances and possible interactions between enriched components.     

Lack of interrelationship between the effects of dietary factors and food withdrawal on carcase quality of broiler chickens

1. Four factorial experiments were carried out to determine whether there is any interrelationship between dietary energy-to-protein (E:P) ratio (experiments 1, 2 and 3) or pelleting the diet (experiment 4) and the duration of food withdrawal (FW), in their effect on carcase quality of broiler male chickens. The quality was evaluated by yields of carcase and breast meat, abdominal fat pad size, and the content and composition of the fat in the meat. The effect of sex on the response to FW was also determined in experiment 3 and that of age in experiment 4. 2. The diet with an E:P ratio higher than recommended decreased the weights of carcase and breast meat significantly (P 0.05) in 2 of the 3 experiments, and consistently increased the size of the abdominal fat pad and the fat content in thigh, but not in breast meat. Abdominal fat pad and the fat in meat of birds fed on this diet contained a significantly higher amount of oleic acid and a lower amount of linoleic acid, than the fat of birds fed on the diets with the recommended and the low E:P ratios. The pellets increased significantly the weights of carcase and breast meat and the relative size of abdominal fat pad. 3. FW for 24 h decreased significantly the weight at slaughter in all 4 experiments, carcase weight in 3 experiments, and breast weight in 1 experiment. However, it did not affect the relative size of the abdominal fat pad, the fat content in thigh and breast meat, and the composition of fatty acids in these tissues and in abdominal fat. None of the variables mentioned was affected significantly by the interaction between the dietary factors evaluated, sex or age of the birds on the one hand, and FW on the other hand. 4. It is concluded that the effect of 24 h of FW on weight at slaughter, carcase and breast meat weights and on fattening, is not affected by dietary E:P ratio, pelleting the diet, or sex and age of the broilers.     

Regulation of taste-active components of meat by dietary leucine

1. Regulation of meat taste is one effective method for improvement of meat quality. In this study, effects of dietary leucine (Leu) content on taste-active components, especially free glutamate (Glu), in meat were investigated. 2. Broiler chickens (28 d old) were fed on diets with graded dietary Leu content (100, 130 or 150% of Leu requirement in NRC, 1994) for 10 d before marketing. Taste-active components of meat (free amino acids and ATP metabolites) and sensory score of meat soup were estimated. 3. Free Glu content, the main taste-active component of meat, was significantly increased by dietary Leu. Compared with the Leu 130% group, free Glu was increased by 17% in the Leu 100% group. Free Glu of meat tended to decrease in the Leu 150% group. In contrast, inosine monophosphate content in meat did not change among all groups. 4. Sensory evaluation of meat soup from the Leu 100 and 150% groups showed that they had different meat tastes. Sensory scores of overall preference, umami taste and chicken-like taste were significantly higher in the Leu 100% group. 5. These results suggest that dietary Leu content is a regulating factor of free Glu in meat. Decreasing dietary Leu induces an increase in the free Glu content of meat and improves meat taste.     

Influence of stewing time on the texture,ultrastructure and in vitro digestibility of meat from the yellow‐feathered chicken breed

This study assessed the influence of stewing (1, 2 or 3 h) on the texture, ultrastructure and in vitro digestibility of meat from the yellow‐feathered chicken, which is a popular broiler chicken in Asia. Results indicated that longer stewing considerably increased cooking loss of the chicken carcass and tenderness of thigh meat. After 3 h of stewing, protein digestibility decreased from 90.5% to 80.3% and fiber diameter decreased by 8.63 μm. The shear force value of breast meat decreased from 32.34 N at 1 h to 10.29 N at 2 h, and then increased to 39.98 N at 3 h. The texture profile of breast meat remarkably decreased during stewing. Moreover, increased stewing time induced longitudinal and transversal shrinkage of muscle fibers and the degradation of the myosin heavy chain. These findings suggested that prolonged stewing (3 h) resulted in decreased meat qualities, based on the changes in cooking loss, digestibility and texture profile, but that stewing for 2 h increased thigh and breast tenderness. Producers could utilize this information to stew yellow‐feathered chicken meat with desirable qualities.     

Effect of reduced dietary protein and supplementation with a docosahexaenoic acid product on broiler performance and meat quality

1. Chicken breast meat is a lean meat due to its low content of intramuscular fat (IMF) resulting in an overall lower acceptability by consumers due to a decrease in juiciness, flavour and increased chewiness. Recently, studies performed in pigs suggested the possibility of increasing IMF by decreasing dietary crude protein (CP) content, an effect possibly mediated through an increased lipogenesis.

2. Dietary supplementation with lipids rich in omega 3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) may modulate an increase in the content of these fatty acids in meat from monogastric animals and, thus, promote the daily intake of n-3 LC-PUFA by humans.

3. LC-PUFA are very susceptible to oxidation, resulting in off-flavours that affect meat quality and consumers’ acceptability.

4. This trial was conducted to assess the effect of reducing dietary CP, from 21% to 17%, on chicken’s meat IMF content and, simultaneously, to evaluate if a complementary supplementation with a proprietary n-3 LC-PUFA source (DHA Gold?) could improve meat quality. These effects were assessed by measuring productive performance and meat quality, oxidative stability, sensory traits and fatty acid profile.

5. A reduction in CP content of broiler diets, from 21% to 17%, balanced for lysine, improved performance while it was not sufficient to increase IMF content in chicken meat. In contrast, DHA Gold? supplementation had a positive impact both in broiler productive parameters and in meat fatty acid profile.

6. In addition, incorporation of 7.4% of DHA Gold? in the diet promoted carcass yield but negatively affected chicken meat acceptability by consumers, due to a decrease of meat oxidative stability.

7. Overall the data suggest that neither a dietary supplementation with DHA Gold? nor a reduction in CP have a direct positive effect in the levels of IMF present in broiler meat.     

Direct supplementation of diet is the most efficient way of enriching broiler meat with n-3 long-chain polyunsaturated fatty acids

1. Concentrations of beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) in poultry meat can be improved by increasing the concentration of n-3 PUFA in poultry diets.

2. A decrease in flavour quality is, however, usually associated with the dietary supplementation with n-3 PUFA, which is due to the susceptibility of PUFA to oxidation.

3. This experiment was conducted to study the effects of introducing two different n-3 fatty acid sources (extruded linseed and DHA Gold?, a proprietary algal product rich in docosahexaenoic acid), either separately or together, on broiler productive performance, and meat quality, oxidative stability, sensory traits and LC-PUFA profile.

4. Birds given the algal product displayed better productive performances than animals from other groups.

5. The data revealed an improvement in the fatty acid nutritional value of meat from birds receiving the algal product and an inefficient conversion of α-linolenic acid (LNA) into LC-PUFA.

6. Metabolisation of LNA in vivo is not sufficient to improve meat quality in n-3 LC-PUFA and direct supplementation of the diet with n-3 LC-PUFA is a better alternative to modulate an increase in beneficial fatty acids of broiler meat.

7. The overall acceptability of meat was negatively affected by the dietary supplementation with 7.4% of DHA, in contrast to the supplementation with 3.7% of DHA, which showed to be efficient in improving LC-PUFA meat content without affecting its sensory properties.