Nutrient and energy retention in weaned Iberian piglets fed diets with different protein concentrations

Fifty-eight purebred castrated male Iberian (IB) piglets (initial BW 9.9 ± 0.1 kg) were used in an experiment to determine the effect of dietary protein content (PC) and feeding level (FL) on the rates of BW gain, whole body protein deposition (PD), and energy utilization between 10 and 25 kg of BW using the serial slaughter method. Treatments followed a 4 × 2 factorial arrangement with 4 PC (201, 176, 149, and 123 g of CP/kg of DM) and 2 FL (0.95 and 0.70 × ad libitum) and 6 or 7 piglets per combination of treatments. All diets were formulated to have an optimal AA pattern. Six piglets were slaughtered at the start of the trial to estimate initial body composition. The experimental pigs were individually housed in an environmentally controlled room (27 ± 2°C) until they reached 25 kg of BW, when they were slaughtered and analyzed for body composition. Positive linear effects of dietary PC on ADG, G:F, and gain:ME intake were observed (P < 0.001). Piglets fed at the highest FL showed greater ADG, G:F, and gain:ME intake (P < 0.001). An average increase was estimated to be 38.0 g of gain/MJ of ME intake. Protein deposition increased linearly from 35.6 to 50.9 g/d with increasing dietary PC (P < 0.001). A daily increase was estimated to be 0.35 g of PD/g of CP intake. Although the maximal genetic potential for PD of the IB piglet was not attained, a maximal value of 59.9 g/d for whole-body PD was achieved when the diet provided 201 g of CP/kg of DM and was fed at 0.95 × ad libitum. Piglets on the highest FL deposited on average 39% more body protein (P < 0.001) than restricted piglets. An average value of 4.39 g increase in PD/MJ of ME intake was obtained for diets containing 201 and 176 g of CP/kg of DM. Maintenance energy requirements and net efficiency of utilization of ME for growth, calculated by linear regression of ME intake on body retained energy, were 427 kJ/kg of BW(0.75)·d(-1) and 0.552, respectively. The corresponding partial efficiencies of utilization of ME for protein and fat deposition were 0.378 and 0.672, respectively, considerably less than the accepted values for conventional pig breeds. Practical diets of the young IB piglet should contain at least 201 g of ideal CP/kg of DM.     

圈养大熊猫主食竹的氨基酸分析

拟通过对大熊猫主食竹中氨基酸含量及其相互间比例的分析,为圈养大熊猫的饲料配方中平衡氨基酸提供理论参考依据。采集了大熊猫喜食的3个产地4种竹叶和竹杆样品各1 7个,共34个样品,并测定了其中1 7种氨基酸的含量。结果表明,竹样品中谷氨酸(Glu)含量最高,其中竹叶中为1 .37%±0 .1 8% ,竹杆中为0 .2 8%±0 .0 6% ;其次为天冬氨酸(Asp)、亮氨酸(Leu)、丙氨酸(Ala)、缬氨酸(Val)、赖氨酸(Lys)、脯氨酸(Pro)、甘氨酸(Gly)、苯丙氨酸(Phe)、酪氨酸(Thr)、丝氨酸(Ser)、精氨酸(Arg) ;半胱氨酸(Cys)含量最低,竹叶中为0 .0 7%±0 .0 4% ,竹杆中为0 .0 4%±0 .0 5 %。竹叶中除Cys含量显著(P <0 .0 5 )高于竹杆外,其余所有氨基酸含量都极显著(P <0 .0 1 )高于竹杆。竹叶中总非必需氨基酸(NEAA)的平均含量为6.2 8%±0 .79% ,竹杆中为4.32 %±2 .5 8% ;竹叶总必需氨基酸(EAA)平均含量为4.66%±0 .5 9% ,竹杆中为3.2 0 %±1 .98%。竹叶和竹杆中NEAA/EAA平均比值分别为1 .35±0 .0 8和1 .2 2±0 .47。     

颈静脉灌注精氨酸对奶牛血液生化指标及必需氨基酸含量的影响

试验旨在研究颈静脉灌注精氨酸(Arg)对奶牛血常规指标、血清生化指标及必需氨基酸含量的影响。选用6头体重、胎次、泌乳期、泌乳量和体况等基本一致的荷斯坦奶牛,采用3×3复拉丁方设计,随机分为3组,即对照组(灌注酪蛋白模式的氨基酸混合物)、Arg灌注组(灌注37.66 g/d)和等氮丙氨酸组(灌注77.24 g/d),进行7 d灌注期+15 d间隔期的颈静脉灌注试验。结果表明:与对照组和等氮丙氨酸组相比,Arg灌注组可降低白细胞计数(P<0.01),而对其他血常规指标无显著影响;等氮丙氨酸组高密度脂蛋白水平高于对照组(P<0.05);低密度脂蛋白以Arg灌注组最高,但3组间差异不显著;与对照组和等氮丙氨酸组相比,Arg灌注组血浆中Arg含量提高(P<0.05),但其他8种必需氨基酸和总必需氨基酸含量未见显著差异。由此可见,颈静脉灌注Arg对泌乳奶牛脂质代谢有一定的调控作用,对血常规指标和必需氨基酸含量的影响不大。     

不同泌乳时间阿拉善双峰驼驼乳中氨基酸的含量变化

研究10峰阿拉善双峰驼第一次分娩后不同泌乳时间驼乳中氨基酸的含量变化。第一次所挤驼乳的蛋白中Thr、Met、Ile、Leu、Phe和Lys的含量分别为6．50、2．10、4．05、7．94、4．38和7．40g／100g，7d时驼乳蛋白中相应的值分别为4．54、2．86、5．50、9．46、4．40和7．89g／100g，之后含量保持相对稳定；而泌乳前1d的时间内必需氨基酸Val的含量较高，之后含量保持相对稳定（6．11—6．25g／100g）。分娩后第一次所挤初乳中Asp、Ser、Gly、Ala和Arg的含量分别为8．39、6．01、3．48、3．76和4．94g／100g，之后随泌乳时间的延长含量降低，到泌乳7d时分别为7．16、4．72、1．49、2．51和4．27g／100g，之后含量保持相对稳定。在研究的泌乳时间内乳样中His（2．50—2．75g／100g）和Phe（4．31-4．73g／100g）的含量没有大的变化。     

Triennial Lactation Symposium: Mammary metabolism of amino acids in dairy cows

Although in dairy cows the mammary gland (MG) is the major net user of essential AA (EAA) supply, milk protein synthesis from absorbed EAA is not a straightforward process. Early studies identified 2 groups of EAA based on different pattern of mammary utilization: group 1 [Met, Phe (+Tyr), Trp], where MG uptake was similar to secretion in milk protein, and group 2 (Arg, Ile, Leu, Lys, Thr, and Val), where uptake exceeded milk protein output. This review examines the validity of this classification under variable protein supply through a meta-analysis, with the outcomes then explained with studies in which the fates of individual EAA were monitored using isotope approaches. For the meta-analysis, the Fick principle, based on stoichiometric transfer of Phe+Tyr uptake to milk protein, was used to estimate mammary plasma flow across all studies. This approach was judged acceptable because doubling Phe supply did not result in mammary oxidation of Phe+Tyr and either limited or no contribution of peptides to Phe and Tyr mammary supply could be detected. The AA content of proteins synthesized by the MG was estimated from milk protein composition, and the uptake-to-output ratio (U:O) for individual AA was re-calculated based on these assumptions. Analysis of individual samples by isotopic dilution resulted in reduced variance compared with analysis on pooled samples performed with an AA analyzer. Globally, the U:O of His and Met is maintained close to unity under variable protein supply. The group 2 AA could be subdivided. First, the U:O for group "2v" AA (Ile, Leu, Val, and Lys) is greater than 1 and varied with protein supply. Accordingly, the increased U:O of Leu, induced by duodenal casein infusion, led to extra-mammary Leu oxidation. Decreasing Lys supply decreased Lys U:O and the associated transfer of N to non-EAA, mainly to Glx, Asx, Ser, and Ala. Second, the U:O of group "2nv" AA, Arg and Thr, does not vary with protein supply. The Arg U:O averages 2.5, whereas the Thr U:O, albeit averaging 1.2, does not differ from unity. Excess of both these AA is probably directed toward the synthesis of non-EAA rather than energy supply. Overall, the ability of the MG to use excess EAA-N supply offers alternative sources of N and C for energy provision, lactose synthesis and non-EAA synthesis. The latter function spares dietary non-EAA for other necessary processes, such as gluconeogenesis and energy supply, in other tissues to support lactation.     

饲粮外源代谢葡萄糖水平对仔猪门静脉回流组织氨基酸利用的影响

本试验旨在研究饲粮外源代谢葡萄糖(MG)水平对断奶仔猪门静脉回流组织(PDV)氨基酸利用量的影响。选择20头健康状况良好、体重在7.74 kg左右的25日龄杜×长×大三元杂交断奶仔猪,分为4个处理组,每组5个重复,给每头猪的门静脉、颈动脉和肠系膜静脉安装血管插管,并安装"T"型回肠瘘管。待仔猪术后恢复正常后,4组分别饲喂MG水平为22.82%、26.59%、36.37%、42.41%的等能、等氮的玉米-豆粕型饲粮,每种饲粮添加0.1%的二氧化钛(TiO2)作外源指示剂。术后3 d,从肠系膜静脉持续灌注对氨基马尿酸(PAH),并从门静脉和颈动脉采血,并且在回肠段收集食糜。结果表明:仔猪PDV氨基酸利用量随着MG水平增加呈先上升后下降的趋势;PDV对17种氨基酸的利用量均在饲粮MG水平为26.59%时达到最大值;必需氨基酸、非必需氨基酸、生糖氨基酸、支链氨基酸也在饲粮MG水平为26.59%时达到最大值(P<0.05)。可见,饲粮适宜MG水平能够显著增加小肠氨基酸消失量和门静脉氨基酸净吸收量,从而显著提高仔猪PDV对饲粮蛋白质的利用效率。     

The influence of suckling interval on milk production of sows

The objective of this study was to determine whether sow milk yield per gland could be increased by reducing the interval between suckles (suckling interval). Eighteen sows were allocated at their first farrowing to three treatments comprising litter sizes of 6 or 12 piglets or a cross-suckling treatment that was imposed to increase suckling frequency. The cross-suckled treatment comprised two groups of six piglets each. Each suckling group was allowed to suckle the sow during 30-min intervals each day between d 6 and d 28 of lactation. The suckling interval was shorter (P < .05) for cross-suckled sows than for sows suckling single litters of 6 or 12 piglets during early lactation (d 10 to 14) and late lactation (d 24 to 28). Average piglet growth rate between birth and 28 d of age was greatest (P < .05) for piglets in the single litters of six and lowest for piglets in the cross-suckled treatments. Single litters of 12 piglets had the highest (P < .05) litter growth rates, followed by the cross-suckled litters and then the single litters of six piglets. The concentration of lactose and fat in milk from sows remained relatively stable, although milk from the cross-suckled sows contained more protein in early lactation (P < .05). Milk yield of sows was not significantly increased (P > .05) by the cross-suckle treatment, although during early lactation, milk yield tended to be greater from sows in the cross-suckle treatment than from sows suckling single litters of six (8,920 g/d vs 7,819 g/d, P < .1). The concentration of DNA and total RNA and the RNA:DNA ratio in mammary glands was unaffected by treatment (P > .05). Sows with single litters of 12 piglets had the greatest total DNA in their udders (P < .05). However, individual gland weights were heavier (P < .05) in cross-suckled sows than in sows with single litters of 6 or 12 piglets. Increased suckling frequency seemed to play a role in increased mammary gland weight and milk production during lactation.     

五指山猪的泌乳性能及泌乳行为

为了研究五指山小型猪的泌乳性能及泌乳行为,试验测定了8头初产五指山母猪初乳(≤3d)常规成分含量、泌乳行为及第3、13、24和35d的泌乳量。结果表明:①五指山猪初乳(≤3d)中的脂肪、蛋白、乳糖和总固形物的含量分别为(6.64±0.56)%、(15.25±1.27)%、(1.99±0.15)%、(27.46±1.25)%。②随产后日龄的增加,母猪泌乳次数和泌乳持续时间逐渐减少,表现为泌乳次数第35日龄比第3和13日龄均少5.14次/d(P<0.05),且下午(12:00￣20:00)比晚上(20:00￣04:00)多1.46次(P<0.05);泌乳持续时间第24日龄显著短于第3日龄(P<0.05);日龄与日泌乳时段对泌乳次数和泌乳持续时间无显著交互作用(P>0.05)。③母猪分娩后0～35d的全期泌乳量和日平均泌乳量分别为31528.59g和900.82g,且第35日龄泌乳量显著高于第3和第24日龄泌乳量(P<0.05);日龄与日泌乳时段对泌乳量无显著交互作用(P>0.05);35d哺乳期内每窝仔猪每克初生体重日耗乳量0.94g,若以普通肉用型猪每窝每克初生体重日耗乳量0.50￣0.99g为参考值,则说明五指山母猪泌乳量充足。本试验结果表明,五指山母猪分泌的初乳干物质含量高、乳糖含量低,分娩后(35d泌乳期内)泌乳量能充分满足仔猪的维持和生长需要。     

德州驴不同部位肌肉组织的常规营养成分、氨基酸和矿物质元素含量的比较

试验研究德州驴不同部位肌肉组织中常规营养成分、氨基酸(AA)和矿物质元素含量的变化。选取年龄、体重相近的健康德州驴32头采用单因素完全随机试验设计。结果显示,粗蛋白的含量以臂三头肌最高,臀肌最低。粗脂肪含量呈相反变化规律,臀肌脂肪沉积较好,嫩度更佳。臂三头肌中的多数单一AA以及必需氨基酸(EAA)、非必需氨基酸(NEAA)、总氨基酸(TAA)、支链氨基酸和功能性氨基酸含量均较高,背最长肌次之,股二头肌较少。背最长肌与臀肌AA的平衡性AA较好,具有较高的EAA/NEAA、EAA/TAA,蛋白质营养价值较高。从鲜味方面来看,臂三头肌的甘氨酸(GLy)、精氨酸(Arg)、丙氨酸(Ala)、谷氨酸(Glu)及呈味氨基酸的含量最高、口感更好、鲜味更佳。矿物质含量测定中,不同部位肌肉中大多数矿物元素没有差异,Cu元素和Zn元素的含量由高到低依次为:臂三头肌>股二头肌>背最长肌和臀肌,且差异显著(P<0.05)。     

ORIGINAL ARTICLE: Effects of herbage ingestion upon ileal digestibility of amino acids in heavy Iberian pigs fed on an acorn‐based diet

We conducted two experiments with heavy Iberian pigs to determine the ileal digestibility of amino acids (AA) in acorns and freshly cut herbage, and the effects of adding fresh herbage upon the supply of ileal digestible AA when pigs were fed on holm‐oak acorns. In Experiment 1, carried out in cannulated pigs of 107 kg bodyweight (BW), daily intake of acorns reached 44.9 g DM/kg^0.75 BW. Arg, His and Thr showed the lowest apparent ileal digestibility (AID) values, whereas Met, the branched‐chain AA and Phe had the highest coefficients. The AID of total EAA was 0.716 but only 0.222 for NEAA. Most of the digestive and absorptive processes of acorn protein occurred before the hindgut. Acorn provides (per kg DM) 2.27 g apparent ileal digestible Lys and 22.7 g apparent total digestible AA. Standardized ileal digestibility (SID) values for EAA, NEAA and total AA were 0.924 ± 0.020, 0.784 ± 0.041 and 0.860 ± 0.029. In Experiment 2 fresh herbage was given to six cannulated Iberian pigs of 140 kg either as a single feed (13.7 g DM/kg^0.75 BW) or as a supplement to acorns (28.4 g DM/kg^0.75 BW). When only freshly cut forage was offered the AID of the EAA, NEAA and total AA was close to 0.65 and supplied (per kg DM ingested) 5.61 g AID Lys and 91.7 g digestible AA. Standardized ileal values were 0.744 ± 0.023, 0.912 ± 0.038 and 0.831 ± 0.030 respectively. The addition of fresh forage to the acorns led to a significant decrease in AID of AA in acorn due to digesta transfer to the hindgut: His (p < 0.01), Met (p < 0.001), Phe (p = 0.092), Thr (p < 0.05) and Val (p < 0.05), but Arg, Lys and the branched‐chain AA remained unaffected. The main contribution of herbage to AA nutrition of the grazing Iberian pig relies mainly on increasing the supply of digestible AA for pig tissues.     

黄河滩区２种豆科牧草不同生育期氨基酸瘤胃降解特性的研究

 以６头装有永久瘤胃瘘管的小尾寒羊为试验动物,用尼龙袋法测定了２种不同生育期豆科牧草苜蓿和白三叶在绵羊瘤胃降解前后氨基酸的变化差异。结果表明,１）２种豆科牧草总氨基酸含量总体上随生育期呈下降趋势,即在分蘖期最高,成熟期最低。总氨基酸／粗蛋白的高峰值都出现在开花期;２）２种豆科牧草的天冬氨酸、谷氨酸、甘氨酸、脯氨酸、酪氨酸、丝氨酸、精氨酸、苏氨酸、赖氨酸和苯丙氨酸在瘤胃中较易降解（犘＜０．０５或犘＜０．０１）;丙氨酸、缬氨酸、蛋氨酸、胱氨酸、异亮氨酸、亮氨酸在瘤胃中有比较好的抗降解作用（犘＞０．０５）;３）随着生育期的推进,成熟牧草中的各种氨基酸在瘤胃中越不易降解。     

Nonessential amino acid content in early weaned piglets following qualitatively and quantitively different protein supplies

A total of 60 piglets of German Landrace weaned at the age of 2 weeks were fed ad libitum with isoenergetic diets of different proteins (casein + dried skim milk, soybean protein + dried skim milk, only soybean protein) and different protein levels in the diet (20, 27, 34, 40% in D.M.). After 4 weeks the piglets were homogenized and examined for their content of non essential amino acids in the whole body mass by ion exchange chromatography. On the fresh and dried material the content of the non essential amino acids Asx, Ser, Glx, Pro, Gly and Ala increased with the higher protein contents of the diet. Decreasing protein quality reduced the content of serine, whereas coincidently the concentration of glycine, especially on the protein levels of 20 and 27% in the diet increased. On the contrary the protein quality had no effect on the concentration of Asx, Glx, Pro and Ala. Related to the whole body protein the highest contents of the non essential amino acids, excepting serine, were found in piglets which got few protein of low quality. Influenced by the different protein supply the proportion of glycine to lysine varied from 1.28 to 2.17. The mentioned changes in the amino acid composition of the piglets are mainly discussed as shiftings in the proportion of organs and tissues and their protein composition.     

不同植物蛋白的日粮对山羊胃肠道食糜氨基酸和肽的影响

选择3只徐淮白山羊,采用4×3拉丁方设计研究不同植物性蛋白源日粮(A:豆粕、B:棉籽粕、C:菜籽粕、D:玉米酒糟)对瘤胃和十二指肠内氨基酸和肽的影响。结果表明:各处理组瘤胃内的游离氨基酸、肽氨基酸浓度分别为8.55、5.38、7.37和7.74mg/L和41.76、36.89、33.65、29.59mg/L;游离氨基酸组成以Glu、Pro所占比例相对较大,Gly、Thr、Leu和Phe所占比例相对较小。肽氨基酸组成以Asp、Glu、Ser、Pro、Val含量相对较高,而Arg、Phe含量相对较低。十二指肠食糜游离氨基酸、肽氨基酸浓度分别为48.71、32.26、35.72、51.23mg/L和11.28、8.54、9.95、12.54g、100gDM;其中游离氨基酸中以Tyr、Ala、Val、Leu、Phe含量相对较高,His、Cys含量相对较低。各组中总氨基酸含量以Ala、Val、Leu、Phe含量相对较高,His、Cys含量相对较低;进入十二指肠的菌体蛋白氨基酸含量,以豆粕组最高,进入十二指肠的饲料氨基酸含量,以玉米酒糟组最高。     

Direct and maternal breed effects on growth and milk intake of piglets: Meishan versus Dutch breeds

Cross fostering techniques were used to evaluate pre-natal (direct genetic and maternal) and post-natal (maternal) breed effects in Meishan and Dutch breeds on milk intake and growth of piglets during the suckling period and growth after weaning. Meishan as well as Dutch sows nursed mixed litters of Meishan and Dutch piglets. Birth weight of Dutch as compared to Meishan piglets was 56% higher. The effects of this birth weight difference on milk intake and growth of piglets were studied. Data on 44 mixed litters nursed by 21 Dutch and 23 Meishan sows were available.At an average birth weight difference, growth rate from birth to 21 and 21–35 d was 25 and 31% higher for Dutch than for Meishan piglets respectively, while milk intake per piglet at days 13 and 30 of lactation was 38 and 36% higher, respectively. Differences between Dutch and Meishan sows were small.Higher growth during the suckling period of Dutch as compared to Meishan piglets was mainly caused by their higher birth weight. Results indicate that Meishan sows have good maternal characteristics, i.e. significantly lower piglet mortality and the ability to raise also the heavier, more demanding Dutch piglets.     

十二指肠大豆小肽梯度灌注对山羊乳腺氨基酸吸收与氨肽酶N基因表达的影响

旨在研究乳腺对不同水平大豆小肽的吸收利用情况.试验选用8只带有十二指肠瘘管和颈动脉、乳静脉血插管的泌乳奶山羊(体质量38 kg±k2 kg),采用交叉设计,分别向十二指肠灌注大豆小肽0、60、120和180 g·d~(-1),连续灌注14 d.结果表明:通过小肽的灌注,(1)提高了乳蛋白产量与乳蛋白含量,而且乳蛋白产量显著提高(P＜0.05).乳脂产量与乳脂含量随着灌注量的升高呈显著下降趋势(P＜0.05).(2)乳腺血浆流星有轻微的提高,但不显著(P＞0.05).与对照组相比,各处理组血浆流量/产奶量出现下降,但只有120 g·~(-1)灌注组下降显著(P＜0.05).(3)与对照组相比,大部分游离氨基酸在60和120 g·d~(-1)灌注组吸收量增加,而在180 g·d~(-1)灌注组出现下降趋势.除了PB-Ile,大豆小肽的灌注增加了所有肽结合必需氨基酸的乳腺吸收.但PB-Val、PB-Leu、PB-Phe、PB-Thr、PB-Met和PB-Lys均在120 g·d~(-1)灌注组吸收率最高.非必需氨基酸中,小肽的灌注提高了PB-Ser、PBTyr、PB-Pro的吸收(P＜0.05),而PB-Gly的吸收却出现了下降(P＞0.05).(4)除了Lys,处理组中所有必需氨基酸的乳中分泌量都高于对照组,从0～120 g·d~(-1)试验组,这些氨基酸乳中分泌量随着小肽灌注量的升高而呈增加趋势(P＜0.05);在180 g·d~(-1)灌注组,大部分必需氨基酸的分泌量增加不显著(P＞0.05),且低于120 g·d~(-1)灌注组.(5)小肽的灌注明显促进了APN基因的表达.灌注60、120和180 g·d~(-1)小肽后,氨肽酶N(APN)的表达分别是对照组的13.55、18.69和10.01倍.结论:乳腺组织能够吸收动脉血液中的小肽,大豆小肽的灌注提高了乳蛋白产量显示乳腺组织可以将吸收的小肽用于乳蛋白的合成.但当乳腺所需的氨基酸达到饱和以后,再增加氨基酸的浓度会出现吸收抑制.APN表达变化与乳腺小肽吸收增加相一致,这可能因为APN是调控小肽乳腺吸收利用的主要酶类之一.     

仔猪内源性精氨酸合成研究进展

精氨酸是幼龄哺乳动物的一种重要的必需氨基酸,具有多种生理生化功能.母乳中严重缺乏精氨酸,致使哺乳仔猪经常出现精氨酸缺乏.外源性精氨酸的拮抗与毒副作用及仔猪精氨酸的内源性合成对其精氨酸平衡起着重要作用.因此,如何调控内源性精氨酸的合成便成了哺乳仔猪精氨酸营养研究的核心.为了便于了解内源性精氨酸合成调控技术在仔猪生产中的应...     

Muscle growth and plasma concentrations of amino acids, insulin-like growth factor-I, and insulin in growing pigs fed reduced-protein diets

Twenty barrows were used to determine if partial replacement of protein-bound AA with crystalline AA (CAA) reduces AA use for muscle tissue and whole-body growth. Barrows (44.2 +/- 1.3 kg of BW) were assigned to 4 diets in a randomized complete block design. Diets consisted of 16.1% CP with no CAA, and 12.8, 10.1, and 7.8% CP containing CAA. As the CP concentration decreased, CAA were gradually increased to meet requirements on a true ileal digestibility basis. Barrows were weighed on d 0 and 13. Blood samples were collected before the morning feeding on d 0, 6, and 12 (prefeeding), and 2 h after the morning feeding on d 13 (postfeeding). Pigs were euthanized on d 13, and liver and right LM were removed and weighed. The reduction in the dietary CP concentration linearly decreased (P < 0.01) ADG, G:F, LM weight, and the CP content of LM. Reducing the CP concentration decreased pre- and postfeeding plasma concentrations of IGF-I (linear, P < 0.01) and insulin (linear, P < 0.10). The reduction in the dietary CP concentration increased prefeeding plasma concentrations of Ala, Gln, Gly, and total AA but decreased Arg, Asn, His, Ile, Phe, Trp, and Tyr (linear, P < 0.05). Plasma concentration of total indispensable AA decreased initially and increased thereafter as the dietary CP concentration decreased from 16.1 to 7.8% (quadratic, P < 0.01). The reduction in the dietary CP concentration increased postfeeding plasma concentrations of Ala, Lys, Met (linear, P < 0.01), and Gly (linear, P = 0.073) and decreased Asn, Ser, Tyr, Arg, His, and Leu (linear, P < 0.05). Plasma concentrations of Ile, Phe, Thr, Trp, and Val decreased initially and increased thereafter as the dietary CP concentration decreased from 16.1 to 7.8% (quadratic, P < 0.05). In muscle tissue, concentrations of free Ala, Asp, Glu, Gln, Gly, and Lys increased (linear, P < 0.05) as the dietary CP concentration decreased. Concentrations of free His, Ile, Phe, Thr, Trp, and Val in muscle tissue decreased initially and increased thereafter as the dietary CP concentration decreased from 16.1 to 7.8% (quadratic, P < 0.05). In summary, the reduction in the dietary protein-bound AA decreased whole-body and LM growth, altered the free AA pool profile in muscle tissue, and decreased plasma insulin and IGF-I. As the replacement of protein-bound AA with CAA increased, 1) free Ala and Gln in muscle tissue increased, indicating an increase of muscle tissue protein breakdown; and 2) utilization of indispensable AA in muscle tissue decreased.     

Recent Advances in Swine Amino Acid Nutrition

Recent advances in swine protein nutrition are characterized by the development of functional amino acids(AA)in regulating fetal and postnatal survival,growth and development. These AA include arginine,glutamine,glutamate,proline,leucine, cysteine and tryptophan. Due to limited knowledge on AA nutrition,pork producers have traditionally paid little attention to supplementing the arginine family of AA to swine diets. Results of recent studies indicate that functional AA serve important regulatory functions in nutrient metabolism,protein turnover, and immune function,therefore enhancing efficiency of feed utilization by pigs. The underlying mechanisms include activation of nitric oxide,mammalian target of rapamycin,gaseous signaling,and AMP-activated protein kinase pathways, as well as anti-oxidative function. Dietary supplementation with arginine,glutamine, proline or leucine to weanling piglets enhances their growth performance. Arginine or glutamine is also effective in increasing milk production by lactating sows. Furthermore,supplementing arginine to the diet of pregnant gilts between days 30 and 114 of gestation increases the number of live-born piglets and litter birth-weight. Availability of feed-grade functional AA holds great promise for improving animal health and nutrient utilization in pig production worldwide. Additionally, feedstuffs of animal origin[e. g. , blood meal (ring dried),feather meal(hydrolyzed),meat and bone meal, porcine protein meal,and poultry by-product meal(both feed- and petfood-grades )]are excellent and cost-effective sources of both essential and functional AA for formulating balanced swine diets.New knowledge on AA nutrition provides a much needed scientific basis for revising the next edition of swine nutrient requirements.     

新疆驼乳粉氨基酸含量和组成分析

检测新疆不同地区3家驼乳加工企业生产的全脂驼乳粉样品。结果表明,驼乳粉平均总蛋白质氨基酸(TAA)含量为24.25 g/100 g,其中人体必需氨基酸(EAA)占44.58%,非必需氨基酸(NEAA)占55.42%。驼乳粉的TAA、EAA含量均高于牛乳粉,EAA/TAA和EAA/NEAA百分比分别达40.00%以上和60.00%以上,符合FAO/WHO/UNU联合专家委员会理想蛋白质的标准,具有较高的营养价值。     

饲粮补充精氨酸对低出生重哺乳仔猪肝脏氧化还原状态和线粒体功能的影响

本试验通过研究精氨酸(Arg)对低出生重(LBW)哺乳仔猪机体氧化还原平衡状态和线粒体功能的影响,探讨Arg改善LBW哺乳仔猪生长发育的可能机制。试验选取体况接近、产期一致和胎次相近的初产母猪所产仔猪,4日龄时,选取20头LBW[体重(1.16±0.08)kg]和10头正常出生重(NBW)[体重(2.07±0.10)kg]仔猪,按体重相近、公母比例一致的原则分为NBW组(饲喂基础饲粮)、LBW组(饲喂基础饲粮)和LBW+Arg组(基础饲粮补充1%Arg)3个组,每组10个重复,每个重复1头猪,人工乳饲养21 d。在第22天,屠宰并收集所有试验猪的血清与肝脏样品,检测生长性能、氧化还原状态与线粒体功能指标。结果表明:1)与NBW仔猪相比,LBW仔猪末重、平均日增重(ADG)和平均日干物质摄入量(ADMI)显著降低(P<0.05),肝脏过氧化氢酶(CAT)活性和ATP含量显著下降(P<0.05),肝脏环氧化酶(COX)ⅠmRNA表达量显著下调(P<0.05),肝脏视神经萎缩症蛋白1(OPA1)mRNA表达量有下调的趋势(P=0.089);2)饲粮补充Arg显著提高LBW仔猪末重、ADG和ADMI(P<0.05),显著提高血清CAT活性和肝脏CAT、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPx)活性(P<0.05),显著提高肝脏ATP含量(P<0.05),显著上调肝脏GPx1和线粒体融合蛋白1(Mfn1)mRNA表达量(P<0.05),并且有上调肝脏CAT(P=0.056)、COXⅣ(P=0.063)和OPA1(P=0.087)mRNA表达量的趋势。以上研究表明,LBW仔猪肝脏抗氧化能力下降,线粒体功能受阻,生长发育受到抑制;而饲粮补充1%Arg显著提高LBW仔猪肝脏抗氧化能力,改善线粒体功能,提高LBW仔猪生长性能。