不同剂量的蛋氨酸铜对肉鸡免疫器官发育和病理变化的影响

选用1日龄健康AA肉仔鸡120只系统研究日粮中添加高剂量的蛋氨酸铜对肉鸡免疫器官发育、铜含量和病理变化的影响.将肉仔鸡随机分成4组,使用蛋氨酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11 mg/kg,3个试验高铜组分别为:110、220、330 mg/kg,试验至60日龄结束.在36日龄,各组随机屠宰6只鸡,计算免疫器官的质量指数;测量60日龄各组免疫器官的铜含量并观察其组织病理变化.结果显示,添加110～330 mg/kg的蛋氨酸铜不同程度地降低了免疫器官的质量指数,极显著地增加了其铜残留量,各免疫器官的病理组织学变化不明显.结果表明,免疫器官中铜含量随日粮铜添加水平升高而升高,日粮中蛋氨酸铜质量浓度达到330 mg/kg都不会引起肉鸡免疫器官明显的病理性损伤.     

不同来源蛋氨酸添加剂对肉鸡生产性能的影响

试验比较了固态蛋氨酸和液态蛋氨酸羟基类似物在肉鸡上的应用效果。选取1日龄平均初始重为(47.2±2)g的Avain肉鸡990只,随机分为2个处理,每个处理15个重复,每个重复33只鸡。处理A添加固态蛋氨酸羟基类似物,纯度为99%(以下简称固蛋),处理B添加液态蛋氨酸羟基类似物,含量为88%(以下简称液蛋),配制日粮时用100g液蛋代替88g固蛋。试验结果表明:试验全期及0~2w、3~4w、5~6w3个阶段两个处理肉鸡的个体质量、日增重、料肉比、采食量等生产性能均无显著差异(P>0.05)。3~4w固蛋组的死亡率显著大于液蛋组(P<0.05),其余各阶段及试验全期两个处理的死亡率无显著差异(P>0.05)。添加固蛋或液蛋每千克增重的饲料成本相差不大,固蛋组比液蛋组低0.38%,经济效益稍好。     

高铜日粮对肉鸡肝脏抗氧化功能的影响

选用1日龄健康商品代AA肉鸡200只随机分成4组,使用硫酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11 mg/kg,3个试验高铜组饲料铜含量分别为110、330和550 mg/kg,试验至50日龄结束,探讨高铜日粮对肉鸡肝脏超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、总抗氧化能力(T-AOC)、过氧化氢酶(CAT)、丙二醛(MDA)含量的影响.结果显示:110、330和550mg/kg组T-AOC、SOD和GSH-Px活性先呈代偿性升高,后表现降低,而CAT和MDA分别表现为代偿性下降和升高.表明日粮铜含量为330mg/kg及其以上可引起肝脏抗氧化功能受损,最终导致肝脏功能紊乱.     

羟基蛋氨酸铜中铜含量的测定

分别用PAN、二甲酚橙、紫脲酸铵作为指示剂,研究了EDTA配位滴定法测定羟基蛋氨酸铜螯合物中铜含量的方法,标准偏差均小于0.2%,相对标准偏差小于0.6%。结果表明,EDTA配位滴定法测定羟基蛋氨酸铜中铜含量,操作过程简单、方便,分析结果重现性好、准确度高,且三种指示剂均可用于铜的测定,其中紫脲酸铵最好,终点变色敏锐。本法可用于不同工艺所合成的羟基蛋氨酸铜中铜含量的测定。     

高铜对肉鸡肝脏线粒体抗氧化功能的影响

为了探讨高铜对肉鸡肝脏线粒体抗氧化功能的影响,试验选择1日龄健康AA肉鸡200只,随机分成4组,使用硫酸铜作为铜源并添加到玉米-豆粕型基础日粮中,对照组饲料中铜含量为11mg/kg,3个高铜组饲料中铜含量分别为110,330,550 mg/kg,试验至肉鸡50日龄时结束.结果表明:高铜110,330,550 mg/kg...     

共轭亚油酸对肉鸡肝脏脂肪含量和脂肪酸组成的影响

共轭亚油酸(CLA)是一系列亚油酸(C18：2)的位置和几何异构体的统称。双键位置有8,10;9,11;10,12和11,13(Eulitz等,1999)。每个共轭的双烯异构体有顺(Cis)、反(Tmns)：T,C;C,C;或T,T几何异物。在反刍动物脂肪中占优势的是c9,T11CLA,它占奶产品CLA的80％,牛肉脂肪中CLA的75％。(Chin等,     

蛋氨酸铜对猪血清铜锌含量及粪铜锌排泄量的影响

为了研究饲粮中添加蛋氨酸铜与硫酸铜对生长猪生长性能、养分消化率、血清铜锌含量及粪铜锌排泄量的影响。选择体重为17．17±2．34kg（P〉0．05）的二元杂交（长×大）生长阉公猪30头进行试验,试猪按完全随机区组设计,依体重和窝别随机分为5个处理,每个处理3个重复,每个重复2头猪,分别饲喂10、150、250mg／kg蛋氨酸铜和150、250mg／kg硫酸铜,试验期30d。结果表明：饲喂蛋氨酸铜组ADG、F／G及表观养分消化率具有明显的优势;血清铜含量随饲粮铜水平的提高而发生显著变化,而高铜组组间血清锌差异不显著;蛋氨酸组粪铜排泄量比硫酸铜组粪铜排泄量显著降低。说明：添加中等水平的有机蛋氨酸铜吸收利用率比高剂量硫酸铜高,且可减少粪铜、锌的排泄。     

不同水平蛋氨酸铜对肉牛营养物质消化率的影响

试验采用4×4拉丁方设计,选用4头年龄2.5～3岁、平均体重(420±20)kg装有永久性瘤胃瘘管的西门塔尔阉牛,以DL-蛋氨酸螯合铜为铜源,以混合精料和风干玉米秸秆为基础日粮,研究在1.3倍维持水平下,日粮添加不同水平的铜(0,8,16,24 mg/kg干物质)对肉牛营养物质消化率的影响.结果表明,8 mg/kg组粗脂肪(EE)的消化率最好,差异不显著(P>0.05);16 mg/kg组无氮浸出物(NFE)的消化率极显著高于对照组(P<0.01);24 mg/kg组有机物(OM)、粗蛋白(CP)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)的消化率最好,其中粗蛋白(CP)的消化率显著高于对照组(P<0.01).日粮中添加24 mg/kg干物质的铜可显著改善日粮营养物质消化率,建议以DL-蛋氨酸螯合铜为铜源时日粮加铜24mg/kg.     

蛋氨酸铜对猪血清铜锌含量及粪铜锌排泄量的影响

为了研究饲粮中添加蛋氨酸铜与硫酸铜对生长猪生长性能、养分消化率、血清铜锌含量及粪铜辞排泄量的影响.选择体重为17.17±2.34kg(P＞0.05)的二元杂交(长×大)生长阉公猪30头进行试验,试猪按完全随机区组设计,依体重和窝别随机分为5个处理,每个处理3个重复,每个重复2头猪,分别饲喂10、150、250mg/kg蛋氨酸铜和150、250mg/kg硫酸铜,试验期30 d.结果表明:饲喂蛋氨酸铜组ADG、F/G及表观养分消化率具有明显的优势;血清铜含量随饲粮铜水平的提高而发生显著变化,而高铜组组问血清锌差异不显著;蛋氨酸组粪铜排泄量比硫酸铜组粪铜排泄量显著降低.说明:添加中等水平的有机蛋氨酸铜吸收利用率比高剂量硫酸铜高,且可减少粪铜、锌的排泄.     

高铜对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响

选用1日龄健康AA肉鸡120只随机均分成4组,使用硫酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11mg/kg,3个试验高铜组饲料铜含量分别为110,220,330mg/kg,试验至60日龄结束,来探讨高铜日粮对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响。结果显示:(1)随着铜浓度的增加和/或饲养日龄的延长,线粒体膜通透性转换孔(Mitochondrial permeability transition pore,MPTP)逐渐扩大(P0.05);(2)血清总胆固醇(T-Ch)含量110,220mg/kg铜添加组低于对照组(P0.05),330mg/kg铜添加组极显著低于对照组(P0.01),而甘油三酯(TG)的含量在各高铜组均极显著低于对照组(P0.01);(3)与对照组相比,肝脏铜含量110,220mg/kg铜添加组有所增加(P0.05),330mg/kg铜添加组极显著增加(P0.01),肌肉中铜含量在各高铜组均极显著高于对照组(P0.01)。这说明高铜可造成肝线粒体不同程度的肿胀和损伤,改变肉鸡脂类的新陈代谢,明显增加肝和肌肉组织的铜含量。     

日粮蛋氨酸水平对肉仔鸡的影响

试验选取600只1日龄AA肉仔鸡,随机分成6组,研究了日粮6个水平的蛋氨酸对其生产性能和血液中甲状腺激素与尿酸含量的影响.结果表明日粮蛋氨酸低于0.28%或高于1.5%时,肉仔鸡生产性能显著下降,血清中尿酸含量显著提高;日粮蛋氨酸0.5%～1.0%时,肉仔鸡生产性能与血清中尿酸含量没有显著差异;血浆中甲状腺激素含量不受蛋氨酸水平的影响.     

甜菜碱替代部分蛋氨酸喂肉鸡的试验

本试验检验了在肉仔鸡日粮中用甜菜碱替代部分蛋氨酸对增重及饲料转化率的影响。试验选用"AA"肉仔鸡1480只,试验组780只,分为6个重复,每个重复130只。对照组700只分为5个重复。每个重复140只,试验组用山东曲阜圣旺制药有限公司生产的无水甜菜碱,纯品≥97％。试验结果表明:前期(0-21日龄)日增重和体重在各处理组之间无显著差异(P>0.05)。中期(22-35日龄)试验组日增重和体重好于对照组(P<0.05)。后期(36-49日龄)试验组日增重较对照组差(P<0.05),整个试验期试验组肉仔鸡的成活率比对照组高出5.859个百分点。     

硼对铜中毒肉用乌骨鸡肝铜含量及肝功能的影响

选用560只1日龄肉用乌骨鸡,采用二因子多水平随机化试验设计研究日粮硼对铜中毒肉鸡肝铜及肝功能的影响。分别在玉米-豆粕型基础日粮中(Cu50.9 mg/kg,B10.1 mg/kg)添加549.1、749.1 mg/kg的铜和49.1、109.1 mg/kg的硼。结果表明,硼可在一定程度上抵御高铜对肝细胞的毒害,并减少肉鸡肝铜的蓄积量,说明硼对肉用乌骨鸡铜中毒具保护效应。     

Effects of methionine and guanidinoacetic acid supplementation on performance and energy metabolites in breast muscle of male broiler chickens fed corn-soybean diets

ABSTRACT

1. Guanidinoacetic acid (GAA) is the single endogenous precursor of creatine, which plays a critical role in energy homeostasis of cells. Since GAA is endogenously converted to creatine by methylation, it was hypothesised that the effects of dietary GAA supplementation might determine the methionine (Met) availability in corn-soybean based diets.

2. A total of 540, one-day-old male Ross 308 broilers were allocated to nine dietary treatments with six replicates (10 birds each) in a 3 × 3 factorial arrangement with three graded levels of supplementary Met (+0.4 g/kg per level), whilst cystine was equal across groups, resulting in a low, medium and high level of total sulphur amino acids, and with three levels of GAA (0, 0.6 and 1.2 g/kg). Birds were fed for 42 days.

3. Increasing levels of supplemental Met enhanced performance indices in all rearing periods, although there was no effect on feed conversion ratio in the grower or feed intake in the finisher periods. Final body weight was 8.8% and 14.6% higher in the birds fed medium and high Met diets, respectively, compared to the low Met level. Relative breast weight and protein content in muscle on d 25 linearly increased with higher levels of Met. At low and high Met levels, growth in the finisher phase was negatively affected by supplementing GAA at 1.2 g/kg. It was suggested that disturbances in methylation homeostasis and/or changes in Arg metabolism might explain these findings. At the end of the grower phase, muscle creatine content was higher when feeding GAA at 0.6 and 1.2 g/kg (4464 and 4472, respectively, vs. 4054 mg/kg fresh muscle in the control group).

4. The effects of dietary GAA supplementation were influenced by the dietary Met level only in the finisher period, which indicates the need for proper sulphur amino acid formulation in diets when feeding GAA.     

Effects of methionine on muscle protein synthesis and degradation pathways in broilers

This study investigated the hypothesis that supplementation of methionine (Met) to broiler diets increases muscle growth due to regulation of molecular pathways related to protein synthesis and degradation depending on the Met source. Day‐old male Cobb‐500 broilers (n = 240) were phase‐fed three different wheat–soya bean meal‐based basal diets during days 1–10, 11–21 and 22–35. Basal diets (Met‐ group, Met + Cys concentration 15% below NRC recommendations) were supplemented with 0.10% or 0.40% Met either as DL‐Met (DLM) or DL‐2‐hydroxy‐4‐(methylthio) butanoic acid (DL‐HMTBA) (equimolar comparison). Breast muscle weights were lower in the Met‐ group compared to all Met‐supplemented groups and were lower in broilers supplemented with 0.10% of DL‐HMTBA compared to the other groups fed Met‐supplemented diets. However, the expression of genes or relative phosphorylation and thus activation state of proteins involved in the somatotropic axis, the mammalian target of rapamycin (mTOR) pathway of protein synthesis, the ubiquitin–proteasome pathway (UPP) and autophagy–lysosomal pathway of protein degradation, the GCN2/eIF2a pathway involved in the inhibition of protein synthesis and in the myostatin–Smad2/3 pathway involved in myogenesis were not affected by Met source. Feeding diets with suboptimum Met + Cys concentrations, however, decreased expression of GHR and IGF1 in liver and muscle and increased that of MURF1 involved in the UPP in the broiler's muscle at day 10 and 21, while that of FOXO and atrogin‐1 and FOXO phosphorylation remained unaffected. Additionally, suboptimum dietary Met concentrations increased expression of the autophagy‐related genes ATG5 and BECN1 at day 35. Met supplementation neither affected gene expression nor phosphorylation of proteins involved in the GNC2/eIF2a and mTOR pathways. These data indicate that protein synthesis was not affected on the molecular level, while protein degradation was marginally affected by dietary Met dosage.     

Effects of dietary supplemental methionine source and betaine replacement on the growth performance and activity of mitochondrial respiratory chain enzymes in normal and heat‐stressed broiler chickens

This study aimed to evaluate the effects of dietary supplemental methionine (Met) source and betaine (Bet) replacement for Met on performance and activity of mitochondrial respiratory chain enzymes (MRCEs) in normal and heat‐stressed broiler chickens. Total of 1,200‐day‐old Ross 308 chicks were allocated to two houses, each consisted of 12 treatments, five replicates of 10 birds each with 2 × 2×3 × 2 (temperature × Met source × Met level × Bet, respectively) split‐plot factorial arrangement. Met level in the basal diets was 70% requirements (Req) that was increased to the requirement or 130% by supplemental dl ‐ or l ‐Met. Bet was or was not substituted at the rate of 30% supplemental dl ‐ or l ‐Met. Feed conversion ratio (FCR) in chicks fed 70% l ‐Met was lower than those fed 70% dl ‐Met diet during 1–10 days (p = 0.04). Broilers fed diets containing requirement or 130% Met, regardless of its source, showed higher weight gain (WG) than those received 70% Met diet during 11–42 days (p < 0.001). Feed intake (FI) of broilers fed 130% Met diet was decreased compared to other two groups during 11–42 days (p < 0.05). One hundred thirty percent Met requirement diet resulted in lower FCR comparing to other two groups during 11–42 days (p < 0.001). Heat‐stressed birds grew less than those under normal condition (p < 0.05). Broilers fed Req Met diet under normal temperature exhibited higher activities of complexes (Cox) I and III (p < 0.05). Cox I activity in heat‐stressed birds fed Bet + diet was similar to those fed Bet‐diet under normal temperature (p = 0.046). It is concluded that performance and the activities of Cox I and III were increased as the level of Met increased. Bet replacement for 30% supplemental Met resulted in similar consequences comparing to non‐Bet replacement diets on performance, but increased the activity of Cox III. l ‐Met was effective than dl ‐Met at the cellular level. High ambient temperature depressed performance and MRCE activity.