肉牛肌内脂肪沉积的营养调控机制

肌内脂肪沉积含量是决定牛肉品质的关键因素.牛肉的肌内脂肪含量与遗传、营养和管理等因素密切相关.文章从肉牛脂肪组织发育程序和肉牛肌内脂肪沉积的营养调控机制等方面进行综述,以期为生产高品质牛肉的研究和生产实践提供参考.     

肉牛肌内脂肪的沉积机制及其营养调控的研究进展

牛肉的肌内脂肪(IMF)含量与肉品质(嫩度、多汁性、风味)呈正相关,而大理石花纹丰富(富含IMF)的牛肉通常来源于饲喂高水平谷实饲料和育肥周期较长的肉牛(30月龄或以上),这种投入产出比较低的模式限制了我国肉牛产业生产高品质牛肉的可持续发展.此外,肉牛肌内脂肪沉积、合成代谢以及营养因素对IMF的影响尤为重要.因此,本文...     

猪肌内脂肪沉积的营养调控

随着生活水平的提高,人们对猪肉的消费,逐渐从对量的要求转变为对质的要求。很多研究者在致力于提高瘦肉率和生产性能,但却导致了猪肉肌内脂肪(IMF)含量大大降低,影响了猪肉品质。在不影响生产性能和增加背脂的前提下提高肌内脂肪,是改善肉品质的一个重要方面。营养调控肌内脂肪,时间短,效果明显,成为近年来的研究热点。综述营养物质对肌内脂肪含量的调控,为读者提供如何在保证瘦肉率的前提下提高猪肉肌内脂肪含量的思路。     

影响肉牛脂肪沉积的遗传和营养因素分析

牛肉是重要的畜产品之一,牛肉中的脂肪及脂肪酸组成是决定牛肉品质的重要因素,尤其是肌内脂肪沉积的含量对牛肉的口感性、嫩度、风味和多汁性等肉品质方面起到重要作用.本文综述了影响肌内脂肪沉积的遗传因素、营养因素和环境因素,以期为调控肉牛肌内脂肪含量提高牛肉品质提供理论依据.     

肉牛肌内脂肪的研究进展

肌内脂肪是影响肉品质的关键因素之一,肌内脂肪含量高,大理花纹丰富,肉细嫩、口感好。作者从影响肌内脂肪含量的主要因素着手,分析了不同的遗传基础、年龄、屠宰部位、日粮等因素对肌内脂肪的影响,为生产优质高档牛肉提供依据。     

肉牛肌内脂肪沉积相关基因的研究

相关基因对肌内脂肪含量的影响,已引起国内外研究人员的广泛关注,尤其是高档肉牛的育种方面。本文就影响肌内脂肪沉积的几个相关基因的发现、表达部位以及对肉牛肌内脂肪沉积的影响进行了综述和展望。     

不同品种肉牛脂联素表达与肌内脂肪沉积的关系

为了探寻不同品种肉牛脂联素与肌内脂肪沉积的关系,选取1.5岁健康无病的延边黄牛和杂交肉牛(西门塔尔×当地黄牛)各30头,分别分成3个重复组,每组10头,育肥期180 d,试验采用荧光定量RT-PCR的方法,观测不同品种肉牛不同育肥阶段脂肪组织脂联素(ADPN)mRNA水平,应用索氏浸提法测定育肥结束期肌内脂肪含量,同时...     

营养调控影响猪肌内脂肪沉积的研究进展

<正>猪肉是我国城乡居民消费量最大的肉食品,随着人们生活水平的不断提高,猪肉品质已越来越受到消费者和生产者的重视。如何提高猪肉品质已成为现代养猪业的重要课题。我们通常说的猪肉品质主要包括pH、肉色、嫩度、肌肉系水力、     

非编码RNA与营养因素调控肉牛肌内脂肪沉积的研究进展

脂肪作为动物机体的主要组成部分,也是畜牧生产中重要的经济性状。脂肪尤其是肌内脂肪（IMF）含量的高低与动物肉品质密切相关。非编码RNA(ncRNA)作为一类转录调节因子,在肌内脂肪沉积过程中发挥着重要的调控作用。本文简要介绍了肉牛的IMF和ncRNA结构与功能,重点阐述了ncRNA与营养在动物脂肪沉积中的研究进展,为深入研究肉牛脂肪沉积的分子机制提供理论基础。     

牛肉肌内脂肪日粮营养调控技术的研究进展

牛肉是一种营养价值较高的食品,具有高蛋白、低脂肪、低胆固醇等优点。随着人们对健康和保健意识的提高,消费者越来越意识到健康和饮食的关系,要求吃到高质量的牛肉。肌内脂肪是影响牛肉品质的重要因素之一,影响牛肉的多汁性、嫩度和风味,适宜的肌内脂肪含量可以改善肉质,提高牛肉的营养价值和食用品质。肌内脂肪的含量和分布受遗传和营养等多种因素的控制和影响,通过营养调控干预机体代谢来改善肌内脂肪是一种切实可行的途径。文章仅就肌内脂肪与牛肉感官品质、营养及保健价值的关系和国内外通过日粮营养调控改善牛肉肌内脂肪含量,提高牛肉质量的技术研究作一综述。     

Effect of a genetic polymorphism in SREBP1 on fatty acid composition and related gene expression in subcutaneous fat tissue of beef cattle breeds

Sterol regulatory element-binding factor 1 (SREBP1) plays an important role in the lipogenesis which affects fatty acid (FA) composition in backfat and consequently influences beef nutritional quality. This study analyzed the association of 84 bp-indel, both short (S) and long (L) alleles in intron 5 of SREBP1, with FA composition and gene expression of SREBP1 in backfat of northern Spanish beef breeds (Pirenaica, Salers and Holstein-Friesian). Phylogenetic analysis suggests that 84 bp-indel of ruminants is a highly conserved region compared with those in the full-length sequence of intron 5 or mRNA of SREBP1 among species. Overall, higher content of polyunsaturated FAs was observed in SL genotype compared to LL genotype of 84 bp-Indel (p < .05). In particular, in Pirenaica, SL genotype was associated with a higher content of stearic (18:0), α-linolenic (18:3n-3) acid, and total n-3 content (p < .05). However, the gene expression of SREBP1 did not differ among genotypes of 84 bp-Indel (p > .05).     

2019年肉牛饲料与营养评价的国外研究进展

文章旨在了解饲料与营养对肉牛生产性能、消化性能、瘤胃发酵以及甲烷(CH4)排放的影响.文章综述了2019年国外的相关文献报道,主要从精饲料、粗饲料及饲养营养综合评价3个方面进行综述.精饲料集中于各种蛋白质饲料和能量饲料的研究.粗饲料研究侧重于粗饲料品种和加工方式对不同生理阶段肉牛生产性能、消化性能和CH4产生的影响.饲...     

Relationships between muscle growth potential,intramuscular fat content and different indicators of muscle fibre types in young Charolais bulls

Genetic selection in favor of muscle growth at the expense of fat should affect characteristics of muscles, and therefore beef quality. This study was conducted with two extreme groups of six animals selected among 64 Charolais young bulls ranked according to their genetic potential for muscle growth. Muscle characteristics were assessed in Rectus abdominis (RA, slow oxidative) and Semitendinosus (ST, fast glycolytic) muscles. Intramuscular fat content and proportions of myosin heavy chains I (slow) and IIA (fast oxido‐glycolytic) and certain indicators of oxidative metabolism (activities of citrate synthase (CS), isocitrate dehydrogenase and cytochrome‐c oxidase (COX); expression of H‐fatty acid binding protein (FABP)) were higher in RA than in ST muscle. Genetic selection for muscle growth reduced intramuscular fat content and the activities of some oxidative metabolism indicators (namely CS, COX only). The positive correlation between muscle triacylglycerol content and A‐FABP messenger RNA level (a marker of adipocyte differentiation) (r = 0.53, P < 0.05) suggests that A‐FABP may be a good marker of the ability of bovines to deposit intramuscular fat. In conclusion, the metabolic muscle characteristics which respond to the selection process in favor of muscle growth clearly differ from the muscle characteristics which allow muscle types to be differentiated.     

肉牛养殖中饮水管理注意事项

随着肉牛养殖业的不断发展,养殖户越来越注重精粗饲料的高效利用以及饲养管理水平的提升,往往容易忽视养殖过程中最基础同时也是非常重要的环节——饮水管理。适宜的饮水条件不仅可以降低肉牛疾病的发生,还可提高饲料消化率及生产性能,从而提高经济效益。     

Changes in molecular species composition of triacylglycerol in subcutaneous fat from beef cattle during fattening

The composition of the molecular species of triacylglycerols (TG) in subcutaneous fat biopsied from Japanese Black steers was studied during the fattening period. An analysis of the fatty acid (FA) composition of the TG showed that palmitic, palmitoleic, stearic and oleic acids were the major FA, together accounting for over 80% of the total FA. The concentrations of C14:0, C16:0 and C18:0 decreased between 10 and 30 months of age, while those of C16:1 c9 and C18:1 c9 increased during the fattening period. The major molecular species among more than 40 compounds were palmitoyl‐dioleoyl‐glycerol (POO) and dipalmitoyl‐oleoyl‐glycerol (PPO). POO showed the highest concentration during the fattening period. The levels of palmitoyl‐oleoyl‐linoleoyl glycerol and some tentatively identified molecular species increased during the fattening period, while the levels of tripalmitoyl, dipalmitoyl‐stearoyl‐glycerol, palmitoyl‐distearoyl and palmitoyl‐stearoyl‐oleoyl‐glycerol decreased with growth. A comparison of the experimental values of TG molecular species with theoretical values derived from the experimental FA contents showed that the FA distribution in TG was non‐random. TG synthesis favors the formation of TG molecular species containing at least one C16 FA, rather than three C18 FA.     

Dystocia in beef heifers: A review of genetic and nutritional influences

Breeding beef heifers for the first time at 15 months of age has potential to increase the efficiency of the beef breeding-cow herd. An increased incidence of dystocia in heifers calving at 2 years of age, compared to mature cows, is a major reason many farmers in New Zealand have not adopted the practice. The predominant type of dystocia affecting 2-year-old heifers is feto-maternal disproportion, a condition in which the fetus is too large relative to the size of the heifer's pelvis. Reducing birthweight of the calf is a means of reducing the incidence of dystocia. Birthweight and length of gestation are determined by genotype of the calf, maternal genetic effects and environmental effects.

Bulls with low estimated breeding values for birthweight have been selected for mating heifers; however, the positive genetic correlation between birthweight and mature weight meant that the progeny of these bulls tended to be lighter at finishing, making them less desirable in the beef industry. The genotype of the dam also plays a role in determining the risk of dystocia; the maternal ability of the dam to nurture the fetus influences birth- weight, and the dam's genetic potential for growth influences the size of her pelvic area. Heavy heifers tend to produce high- birthweight calves, counteracting the reduction in the incidence of dystocia resulting from the larger pelvis in larger heifers.

Manipulating feeding level during pregnancy offers an alternative method for manipulating the birthweight of calves. Little is known about the effects of nutrition in early gestation on placental development or birthweight of calves. No differences in the birthweight of calves have been observed in response to variation in feeding in mid-pregnancy, and variable responses in birthweight and the incidence of dystocia to feeding in the third trimester of pregnancy have been reported. Differences in birthweight have not always resulted in differences in the incidence of dystocia, primarily due to differences in liveweight of the heifer also induced by feeding regimens. Variability in the incidence of dystocia in response to feeding level in the third trimester of pregnancy makes it difficult to make recommendations for the feeding of heifers at this stage of gestation. More research is needed into the effects of nutrition in early gestation on fetal and placental development in cattle.     

Estimation of additive, maternal and non-additive genetic effects of preweaning growth traits in a multibreed beef cattle project

Data from purebred and crossbred calves, consisting of Afrikaner (AF), Charolais (CH), Simmental (ST) and Hereford and Aberdeen Angus combined (HA), were analyzed to estimate breed additive effects, breed maternal effects, average individual heterosis and average maternal heterosis. The traits studied were birthweight (BW), weaning weight (WW) and preweaning average daily gain (ADG) (kg). A multiple regression procedure was used for the estimation of these genetic effects and for predictions for breed crosses that were not included in the data set. Crosses containing higher proportions of CH or ST were heavier at birth and weaning than the other crosses and purebreds. The direct effects of BW were negative and significant (P < 0.05), except that of the CH, which was the highest. The regression coefficients were ?24.87, ?18.16, ?22.80 and ?27.02 for AF, CH, ST and HA, respectively. The maternal effects were not significant. Both average individual and average maternal heterosis regression coefficients were also not significant for BW. Regression coefficients of both direct and maternal effects for WW were not significant and were characterized by large standard errors. Average individual heterosis and average maternal heterosis regression coefficients were, however, significant (P < 0.01) and the values were 5.34 and 2.19, respectively. A similar pattern was observed for ADG, except for the regression coefficients of the maternal effects, which were significant, with larger estimates for AF and ST reflecting their superior mothering ability. The values were 0.01, 0.13, 0.13, 0.03; ?0.82, ?0.85, ?0.85, ?0.81; 0.03 and 0.01 for direct effects and maternal effects of AF, CH, ST and HA; and average individual heterosis and average maternal heterosis, respectively. Means and standard errors of purebreds and their F₁ crosses not included in the dataset were predicted.     

日粮营养水平和添加莫能菌素对肉牛生产性能的影响

通过饲养试验来研究不同营养水平和是否添加莫能菌素对宁夏地区西门塔尔杂交阉牛增重效果和经济效益的影响。结果表明,与对照组相比,高精粗比(67:33)组和添加200 mg/(头.d)莫能菌素组的平均日增重提高65.18%和37.5%(P<0.05);料肉比降低33.29%和20.58%,显著提高经济效益。     

基于DISCERN算法筛选影响肉鸡脂肪沉积的关键基因

选取法国高低脂2组7周龄肉鸡腹部脂肪的RNA測序转录组数据中的17 934个基因,采用差分稀疏调节网络(differential sparsE regulatory network,DISCERN)算法对相应数据进行分析,以期筛选出影响肉鸡腹部脂肪沉积的关键基因,并识别肉鸡不同基因表达数据之间网络差异关系,推断基因调控...