Research Progress on Influence Factors of Mutton Quality

Meat quality means the characteristics such as appearance is related to palatability in fresh meat or manufactured meat, it includes meat color, meat structure, hardness, marbling, water holding capacity and so on.The physical characteristics of mutton quality determines the consumer acceptability of meat and there is a close relationship between chemical composition of mutton quality and nutrient substance.With the improvement of living standards, consumers are increasingly high demand for mutton.From quantitative to qualitative change, we need to continuously improve mutton quality.At present, the production of high quality animal products has become a hot topic.This paper is a summary of the effects of breed, gender, age, environment and feed nutrition on mutton quality, and aims to provide a scientific basis for improving of mutton quality with nutritional regulation measures.     

东北地区春玉米临界氮浓度稀释曲线的建立和验证

过量施氮是目前玉米栽培中存在的普遍现象,基于临界氮浓度稀释曲线计算得出的氮营养指数是诊断氮营养丰缺的重要手段。基于东北地区4个生态点的试验数据,构建了东北地区春玉米临界氮稀释曲线,并在此基础上建立了氮营养指数模型和需氮量模型,结果表明,东北地区春玉米地上部临界氮浓度与生物量符合幂函数关系。利用独立试验资料对建立的临界氮浓度稀释曲线进行检验,发现基于临界氮浓度稀释模型计算的氮营养指数可以准确诊断玉米植株的氮营养状况,并计算出实时的氮素需求量。该研究建立的东北地区春玉米临界氮稀释模型可以为该地区春玉米的氮营养诊断和动态调控提供较好的理论和技术指导。     

日粮钙水平对空怀期云南半细毛羊生长性能及血清生化指标和繁殖相关激素的影响

试验旨在探讨日粮钙水平对空怀期云南半细毛羊生长性能、配种前血清生化指标和繁殖相关激素的影响,为开展空怀期云南半细毛羊营养需要量研究提供参考。选用50只体况良好、体重相近、38月龄的经产2胎空怀云南半细毛羊,随机均分为5组,分别饲喂0.40%(无外源钙)、0.45%、0.53%、0.66%、0.85%5个钙水平的日粮。预试期14d,正试期30d。结果表明:0.53%钙水平组云南半细毛羊的总增重、平均日增重、平均日采食量、耗料增重比等指标相对优于其他组;0.40%钙水平日粮组的血清钙最高,血清碱性磷酸酶、甲状旁腺素、钙、磷组间差异不显著(P>0.05);繁殖相关激素各组间表现不一,0.40%钙水平组雌二醇水平最高(P>0.05)。在日粮磷水平为0.20%水平条件下,0.53%钙水平组的空怀期云南半细毛羊表现出较好的生长性能,可为临配种前生理生化和激素水平提供较好准备;增加日粮钙水平,未见对以上指标有明显的正向增强作用,可能与日粮钙磷比失衡有关。     

Can additional N fertiliser ameliorate the elevated CO2‐induced depression in grain and tissue N concentrations of wheat on a high soil N background?

Elevated CO₂ stimulates crop yields but leads to lower tissue and grain nitrogen concentrations [N], raising concerns about grain quality in cereals. To test whether N fertiliser application above optimum growth requirements can alleviate the decline in tissue [N], wheat was grown in a Free Air CO₂ Enrichment facility in a low‐rainfall cropping system on high soil N. Crops were grown with and without addition of 50–60 kg N/ha in 12 growing environments created by supplemental irrigation and two sowing dates over 3 years. Elevated CO₂ increased yield and biomass (on average by 25%) and decreased biomass [N] (3%–9%) and grain [N] (5%). Nitrogen uptake was greater (20%) in crops grown under elevated CO₂. Additional N supply had no effect on yield and biomass, confirming high soil N. Small increases in [N] with N addition were insufficient to offset declines in grain [N] under elevated CO₂. Instead, N application increased the [N] in straw and decreased N harvest index. The results suggest that conventional addition of N does not mitigate grain [N] depression under elevated CO₂, and lend support to hypotheses that link decreases in crop [N] with biochemical limitations rather than N supply.     

Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula

Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides’ antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains’ interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca²⁺ had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides’ stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.     

调环酸钙25%悬浮剂对直播稻抗倒伏和产量性状的影响

为了研究新型植物生长调节剂调环酸钙在直播稻上的应用效果,本研究设计了调环酸钙25%悬浮剂在直播稻武运粳8号上的田间试验,用来了解其对直播稻的抗倒伏性状和产量性状的影响。试验结果表明:在直播稻武运粳8号的分蘖期使用调环酸钙25%悬浮剂12~15g/667m2均能够显著降低水稻的株高,缩短茎基部节间长度,提高水稻的抗倒伏能力,同时也能显著提高水稻产量。     

桑叶养猪实用技术

桑叶养猪实用技术分为桑树种植技术和桑叶干粉发酵养猪技术两个部分。利用荒地种植桑树,降低生猪养殖饲养成本,桑叶养猪种养结合,成为生态农业典范。桑叶干粉发酵技术,提高了桑叶干粉的可消化率和饲料功能。桑叶干粉发酵料占配方6%~10%,做成桑叶猪饲料,替代3%~5%鱼粉、豆粕等蛋白质饲料,节约了饲料成本。桑叶喂养猪(简称桑叶猪,下同)的猪肉中含有肌苷酸等风味物质,显著提高猪肉胴体品质和猪肉风味。设计猪尿处理,采用红泥膜沼气池降解工程工艺应用后,降解水兑2倍清水对桑树喷灌工艺,减少人工处理劳力和成本费用。设计10%抗非洲猪瘟中药饲料添加剂+桑叶饲料,预期防治非洲猪瘟总效果85%以上。桑叶养猪实用技术可行,供同行参考。     

围产期奶牛血钙影响因素及其与生产性能关系分析

本试验旨在探究围产期奶牛血钙浓度影响因素及其与生产性能的关系。于2018年7月20日—8月15日对北京地区36头围产期健康荷斯坦牛的血钙浓度进行测定,收集该牛场奶牛生产性能测定(DHI)报告,利用固定效应模型分析不同胎次、体况评分(BCS)、健康状况及血钙浓度变异度对血钙浓度的影响。结果表明:血钙浓度与产后天数存在显著的正向相关关系;经产牛的血钙浓度(1.40 mmol/L)极显著高于初产牛(1.31 mmol/L);不同BCS分组奶牛血钙浓度差异不显著;健康组的血钙浓度(1.41 mmol/L)显著高于患病组(1.30 mmol/L);血钙浓度变异度的大小影响奶牛的产奶量,初产奶牛低变异度组的产奶量(16.70 kg/d)显著高于中变异度组(9.75 kg/d)和高变异度组(5.63 kg/d)。本研究进一步揭示了围产期荷斯坦牛血钙浓度的变化规律以及其影响因素,为预防奶牛产后低血钙症的发生以及制定提高奶牛生产性能的饲养管理策略提供参考。     

动态细分饲粮营养供给对肉鸡生产性能、肉品质、氮与磷代谢率及血清生化指标的影响

本试验旨在根据肉鸡生长曲线及动态营养需要,研究动态细分饲粮营养供给对肉鸡生产性能、肉品质、氮、磷代谢率及血清生化指标的影响。选取1日龄爱拔益加(AA)肉鸡240只(公母各占1/2),随机分为3个组,分别为A组:每3.5 d 1个营养标准(1~7日龄1个营养标准);B组:每7 d 1个营养标准;C组:每14 d 1个营养标准。每组8个重复,每个重复10只鸡,试验期42 d。结果表明:1)C组肉鸡的平均日增重(ADG)显著高于A、B组(P0.05),料重比(F/G)显著低于A组(P0.05)。A、B组肉鸡生产性能指标差异均不显著(P0.05)。不同动态细分饲粮营养供给方式对肉鸡肉品质的影响无显著差异(P0.05)。2)不同动态细分饲粮营养供给方式对肉鸡氮、磷代谢率的影响无显著差异(P0.05)。3)肉鸡28日龄时,C组肉鸡血清尿素氮(UREA)含量显著高于A组(P0.05);42日龄时,C组肉鸡血清UREA含量显著高于A、B组(P0.05),但A、B组肉鸡血清UREA含量差异不显著(P0.05)。4)不同动态细分饲粮营养供给方式对肉鸡血清皮质酮(CORT)含量及总抗氧化能力(T-AOC)的影响差异不显著(P0.05)。综上所述,每14 d 1个营养标准可使肉鸡的生产性能达到最佳,从实际操作的复杂性考虑,每7 d 1个营养标准可更好地满足饲粮的氨基酸平衡。     

黔南州核桃优树叶片营养元素和果实品质相关分析

为了分析叶片营养元素对黔南州核桃优树坚果品质的影响,通过方差分析和相关分析研究了叶片营养元素与坚果品质之间的相关关系。结果表明:不同品种的核桃优树单株的坚果品质指标间存在显著差异;叶片钙、铜和锰显著影响核桃坚果品质。可以通过核桃叶片营养元素的诊断来提高坚果品质。