高产泌乳母猪饲粮蛋白质与赖氨酸参数的研究

以产活仔 1 2头以上的经产母猪为对象 ,研究蛋白质水平分别为 1 1 .5 %、1 3 .8%、1 5 .9%、1 8.0 %和2 0 .2 % ,相应的赖氨酸为 0 .61 %、0 .74 %、0 .87%、1 .0 %和 1 .1 2 %的 5种等能饲粮对母猪繁育、泌乳及血浆尿素氮和游离氨基酸含量的影响。结果表明 :随着蛋白质和赖氨酸摄入量的提高 ,母猪泌乳期失重减少 (P <0 .0 5 ) ,泌乳量则显著提高 (P <0 .0 5 )。仔猪 2 0和 3 5日龄的窝重均显著受母猪饲粮营养水平的影响 (P <0 .0 5或P <0 .0 1 )。血浆尿素N随蛋白质和赖氨酸水平的提高而提高 (P <0 .0 5 ) ,但血浆游离氨基酸总含量无显著差异。无论母猪繁育效果和泌乳性 ,均以第 4组饲粮即母猪日摄入蛋白质 868g,赖氨酸 4 8.3g时 ,获得了最佳效果     

Concentrations of free amino acids in maternal and fetal plasma from conscious catheterised ewes during the last five weeks of pregnancy

Concentrations of amino acids, urea, glucose, fructose and corticosteroids were measured in maternal and fetal plasma from nine Scottish Blackface ewes during the last 35 days of pregnancy. During this period maternal plasma levels of most amino acids did not change significantly. In fetal plasma the concentrations of most amino acids decreased or remained relatively constant until about 20 days before birth (day -20) and then increased as term approached. Glucose levels in plasma from both sources did not change, but urea concentrations rose to maximum values about day -20. Except for valine and isoleucine, the concentrations of amino acids in fetal plasma varied independently of levels in maternal plasma up to day -20, but thereafter 10 amino acids, including seven essential amino acids, showed a significant positive correlation with maternal values. Possible causes of the observed variations in fetal plasma composition are discussed.     

内毒素血症山羊血浆氨基酸含量变化与氧自由基代谢的关系研究

以内毒素诱发山羊微循环障碍为模型,１２只山羊随机分为两组：Ａ组为对照组（Ｎ＝６）,Ｂ组为实验组（Ｎ＝６）。检测内毒素血症山羊血浆１７个氨基酸含量变化,以及氧自由基代谢指标血浆丙二醛含量,超氧化物歧化酶和谷胱甘肽过氧化物酶活性。     

Ascorbic acid status of female camels during different phases of reproduction

There is suggestive evidence that a low status of ascorbic acid in camels enhances their risk for infectious diseases. This study was carried out to disclose the role of reproduction, if any, in affecting ascorbic acid status. The associations between the reproductive cycle and ascorbic acid contents in plasma and leukocytes were studied in Sudanese camels browsing on local vegetation. Ascorbic acid status was found to be lowest during pregnancy and highest during lactation. Estrus versus non-estrus was associated with high vitamin C status. Brucellosis-positive camels showed decreased levels of ascorbic acid in plasma and leukocytes. Possibly, the phases of non-estrus and pregnancy in camels invoke an increased susceptibility to infectious diseases due to a lower ascorbic acid status.     

颈静脉灌注不同模式的氨基酸混合物对泌乳奶牛乳蛋白合成的影响

本试验旨在比较颈静脉灌注酪蛋白模式和理想模式的氨基酸混合物对泌乳中期荷斯坦奶牛乳产量、乳成分以及乳腺对氨基酸摄取利用的影响。选择8头泌乳中期[泌乳天数:(82±11)d]荷斯坦奶牛作为试验动物,试验采用随机区组设计,将试验牛随机分为2组,分别颈静脉灌注160g/d酪蛋白模式(Casein组)和理想模式的氨基酸混合物(R组)。2个试验组分别以各自灌注前作为空白对照组(C1组为Casein组的空白对照组,C2组为R组的空白对照组)。预试期14d,灌注期5d。试验采用全混合日粮(TMR)饲喂,以玉米、豆粕、棉籽粕、玉米青贮、苜蓿干草和羊草为主要原料,参照NRC(2001)奶牛饲养标准配制。结果表明:灌注酪蛋白模式的氨基酸混合物后,乳蛋白产量和含量较灌注前呈上升趋势(乳蛋白产量上升7.14%,P=0.078;乳蛋白含量上升3.27%,P=0.072);并且,奶牛动脉血浆中异亮氨酸(Ile)、亮氨酸(Leu)、赖氨酸(Lys)和组氨酸(His)的浓度较灌注前有不同程度的上升(Ile的浓度提高31.5%,P=0.097;Leu的浓度提高65.9%,P=0.041;Lys的浓度提高36.9%,P=0.088;His的浓度提高40.1%,P=0.010),而苏氨酸(Thr)、缬氨酸(Val)、蛋氨酸(Met)、苯丙氨酸(Phe)和精氨酸(Arg)的浓度在数值上虽较灌注前高但无显著差异(P0.05)。灌注酪蛋白模式的氨基酸混合物后,奶牛乳腺对天冬氨酸(Asp)和半胱氨酸(Cys)的摄取率显著升高(Asp的摄取率提高95.2%,P=0.031;Cys的摄取率提高49.6%,P=0.031),而奶牛乳腺对甘氨酸(Gly)的摄取率显著降低(降低158.3%,P=0.041)。灌注理想模式的氨基酸混合物后,乳蛋白含量比灌注前有上升趋势(提高5.78%,P=0.064),而乳脂产量显著低于灌注前(降低8.57%,P=0.015);并且,奶牛动脉血浆中Arg的浓度有上升趋势(提高18.0%,P=0.093),而酪氨酸(Tyr)的浓度呈下降趋势(降低47.8%,P=0.074)。灌注理想模式的氨基酸混合物后,奶牛乳腺对谷氨酸(Glu)、Cys和Ile的摄取率显著上升(Glu的摄取率提高118.7%,P=0.015;Cys的摄取率提高77.4%,P=0.032;Ile的摄取率提高46.0%,P=0.012),而奶牛乳腺对Ser的摄取率呈下降趋势(降低56.2%,P=0.052)。灌注氨基酸混合物后,Casein组乳脂产量增量显著高于R组(P=0.012),且Casein组的乳产量增量(P=0.095)和乳糖产量增量(P=0.091)较R组有升高的趋势,而2组间其他指标增量无显著差异(P0.05)。由此得出,在本试验条件下,颈静脉灌注酪蛋白模式和理想模式的氨基酸混合物均可提高泌乳奶牛的乳蛋白含量,而灌注酪蛋白模式氨基酸混合物同时可以促进乳蛋白产量的升高,因此,颈静脉灌注酪蛋白模式氨基酸混合物的效果优于灌注理想模式氨基酸混合物。     

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。     

Dynamic ideal protein and limiting amino acids for lactating sows: the impact of amino acid mobilization

The limiting amino acids for lactating sows were determined using 28 primiparous sows that were intentionally underfed both energy and protein during a 21-d lactation. Groups of four sows were allotted to litter-size treatments of 6, 7, 8, 9, 10, 11, or 12 by cross-fostering as needed within 48 h postpartum. Sows were killed on d 21 of lactation. The carcass, liver, gastrointestinal tract, reproductive tract, mammary gland, and other viscera were separated, weighed, ground, and analyzed for dry matter, crude protein, and amino acids. Simple linear equations were obtained for each amino acid within tissues as a function of litter size. The mobilization of amino acids from carcass, liver, gastrointestinal tract, reproductive tract, and other viscera increased as litter size increased. Amino acids were accreted to mammary glands as litter size increased (2.65 g lysine/21 d for each one-pig increase in litter size). Milk production needs were estimated (49.9 g lysine/21 d for each one-pig increase in litter size). The quantity of each amino acid required additionally as litter size increased was obtained from the difference between amino acid needs for milk production and mammary gland growth and those provided from tissue mobilization. The relative ratio among amino acids that are required additionally (ideal amino acid pattern) was compared with the relative ratio of amino acids that can be provided from a corn-soybean meal lactation diet. From the comparison, it was shown that threonine and lysine are the first-limiting amino acids, followed by valine, when tissue mobilization occurs during lactation. Lysine is the first-limiting amino acid, and valine becomes second-limiting followed by threonine, when sows do not mobilize body tissues during lactation. Thus, the limiting order of essential amino acids changes depending on feed intake and tissue mobilization of sows during lactation. Proper feeding of lactating sows should consider the expected degree of tissue mobilization during lactation.     

过瘤胃保护蛋氨酸对奶牛乳和血浆氨基酸含量及血液生化指标的影响

本研究采用在生产条件下的对比饲养试验,通过研究日粮中添加本实验室研发的过瘤胃保护蛋氨酸产品对高产荷斯坦牛乳和血浆氨基酸含量与组成、血液生化指标的影响,验证产品的性能,探讨过瘤胃保护蛋氨酸对奶牛生产性能和乳成分产生影响的机理。试验选择2～5胎之间、日产奶量30kg以上、处于泌乳高峰期的荷斯坦牛20头,随机分为两组,试验组每头每天添加本实验室研发的过瘤胃保护蛋氨酸产品75g。试验结果表明,日粮中添加该产品可明显增加荷斯坦牛乳大多数种类氨基酸和总氨基酸含量,使11种血浆游离氨基酸含量有不同程度的增加,总游离氨基酸含量有一定程度的提高,血浆白蛋白、球蛋白、总蛋白含量明显增加,6种血浆游离氨基酸含量有不同程度的降低,谷草转氨酶和谷丙转氨酶活性增强,游离脂肪酸含量和葡萄糖含量明显上升,尿素氮含量明显降低。上述结果进一步验证了本实验室研发的过瘤胃保护蛋氨酸产品具备较好的瘤胃稳定性和小肠可消化性,在一定程度上揭示了其提高产奶量和乳蛋白含量的作用机理。     

Progesterone receptor mRNA levels during pregnancy, labor, lactation and the estrous cycle in rat uterus

Progesterone plays important roles in the regulation of female reproduction. In this study, progesterone receptor (PR) mRNA levels in rat uterus during pregnancy, labor, lactation and the estrous cycle were examined by competitive RT-PCR. During pregnancy and lactation, PR mRNA levels had decreased on day 20 of pregnancy (P20) and P21 compared with P15 but increased during labor. After a decline on day 1 of lactation (L1), PR mRNA levels had increased again on L3 and L14 compared with P15, P18, P20, P21 and P21pm (at 2200-2300 h on P21). There was no significant change in the PR mRNA level during the estrous cycle. The PR mRNA level did not change during 1 week of progesterone treatment or afterwards. Injection of 17beta-estradiol did not affect PR mRNA levels in rats treated with progesterone or those without any injections. In rats on P18, 17beta-estradiol injection did not change PR mRNA levels after sham-operation but induced an increase in PR mRNA levels of rats ovariectomized 6 h before the treatment. These results suggest that uterine PR mRNA levels are differently regulated during late pregnancy, labor and lactation, and during labor estrogen is one of the essential factors for the increase in PR mRNA levels.     

Nutritional value and physiological effects of soya-free diets fed to rats during growth and reproduction

The objective of the study was to assess the effects of substitution milk and egg for soya products in breeding diets for rats, with concomitant decrease of the dietary protein level and supplementation with amino acids. Soya-containing (S) and two soya-free (NS and NSA) diets were evaluated as protein and energy sources, and their effects on reproductive performance during two cycles, and on the quality of the offspring were assessed. Organ weights were registered in females and blood parameters were determined in males. In the offspring males from S and NS groups, plasma LH, testosterone and prolactin levels were measured on the 22nd and the 60th day of life. The S diet contained more protein of smaller concentration of methionine and cystine and lower biological value than both NS and NSA diets and promoted similar post-weaning growth rate, similar body weight changes of dams during gestation and lactation and slightly lower mating efficiency. Within each reproductive cycle, the number and individual and total body weight of newborn and weanling pups did not differ but in two cycles mean number of neonates per litter and mean litter weight were significantly lower on S than on NSA diet. Plasma concentration of hormones did not differ in 22-day-old offspring males while in the older ones LH and prolactin levels were higher in animals fed on S than on NS diet. It is concluded that replacing soya protein by milk and egg protein with concomitant lowering dietary protein level and amino acid supplementation does not impair the growth rate and tends to improve reproductive performance. Feeding soya-free vs. soya-containing diets differentiates hormonal status of young males.     

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。     

Synthesis and secretion of A-type natriuretic peptide in the auricular cardiocytes during pregnancy and lactation in mouse

A-type (atrial) natriuretic peptide (ANP) levels in the auricular cardiocytes and plasma were examined by immunohistochemistry, electron microscopy, and radioimmunoassay in pregnant and lactating mice. Additionally, the cardiocyte ANP mRNA expression was measured by the polymerase chain reaction method. ANP-immunoreactivity (IR) and the number of ANP-granules in the cardiocytes on the 18th day of gestation were greater than those in virgin controls, but the plasma ANP concentration decreased on the 18th day of gestation. On the day of delivery, ANP-IR and the number of ANP-granules in the cardiocytes were decreased compared to those during the pregnancy and to those in virgin controls, and then began to increase continually until the 15th day of lactation. Plasma ANP concentration after delivery was significantly higher than that during pregnancy, and than that in virgin controls, and continued to increase until the 15th day of lactation. Cardiocyte ANP mRNA expression was highest on the day of delivery compared to that in all the other times. In conclusion, these results suggested that the circulating systems of ANP during pregnancy and lactation were regulated differentially.     

Response of swine to periparturient vitamin C supplementation

Two experiments were conducted, involving 68 third-litter sows and 20 first-litter gilts in Exp. 1 and 82 first-litter gilts in Exp. 2. On d 108 of gestation, the dams were moved into individual crates, stratified by parity and breed, and randomly assigned within strata, to one of two treatments: (1) fed a basal 16% protein corn-soybean meal diet, 1.8 and 2.7 kg once daily before farrowing and for the first 7 d of lactation, respectively, and then ad libitum until pigs were weaned at 28 d of age, and (2) fed the basal diet plus 1 g of L-ascorbic acid (vitamin C)/dam daily from d 108 of gestation through d 7 of lactation and on the same feeding schedule as for treatment 1. In Exp. 1, no effect of vitamin C supplementation was observed in sows or gilts on total pigs born/litter, number of live pigs/litter or average live pig weight at birth, 7 or 28 d of age, or on plasma vitamin C concentration of dams at d 108 of gestation or d 7 of lactation or of pigs at birth, 7 or 28 d of age. However, there was a lower (P less than .01) plasma vitamin C concentration of the dams at d 7 of lactation than at d 108 of gestation. Plasma vitamin C concentration also declined (P less than .01) as pigs aged. In Exp. 2, with all gilts, vitamin C supplementation again showed no effect on any of the reproductive traits measured in Exp. 1. It is concluded that daily supplementation of 1 g of vitamin C to either sows or gilts from d 108 of gestation through d 7 of lactation has no beneficial effect on the reproductive or lactation performance of swine.     

Acyl Ghrelin and Metabolic Hormones in Pregnant and Lactating Sows

Ghrelin, the endogenous ligand of the growth hormone (GH) secretagogue receptor, is considered a pleiotropic regulator involved in a large array of functions, including control of energy balance, regulation of food intake and, more recently, modulation of the reproductive axis. The present study was aimed at determining the changes in plasma concentrations of acyl-ghrelin in pregnant and lactating sows, with special emphasis on the relationship with the levels of GH, leptin, non-esterified fatty acids (NEFA) and insulin-like growth factor (IGF-1). Blood samples were collected via jugular venipuncture from 22 multiparous sow 30, 60 and 90 days after artificial insemination, 7 and 21 days after farrowing and at first oestrus post-weaning. Plasma concentrations of acyl-ghrelin, leptin, GH and IGF-1 were quantified by validated radioimmunoassay; NEFA were determined using a colorimetric procedure. Plasma acyl ghrelin levels were highest at 30 days of pregnancy and decreased thereafter and during lactation. At the beginning of lactation, GH, IGF-1 and NEFA concentrations significantly increased, while a significant reduction occurred in leptin. In conclusion, ghrelin concentrations in sow maternal circulation does not seem to play an important role in maintaining circulating GH levels during lactation; moreover, ghrelin is not associated with leptin, NEFA and IGF-1 levels.     

亚急性瘤胃酸中毒耐受性不同的奶牛血浆和乳中脂肪酸及代谢物组成分析

为比较研究对亚急性瘤胃酸中毒（SARA）耐受性不同的奶牛血浆和乳中代谢组的差异，试验选用12头装有永久性瘤胃瘘管的泌乳中期荷斯坦奶牛［泌乳天数=（114±22） d］，饲喂精粗比为4∶6的全混合日粮。在试验期第20和21天晨饲后0、2、4、6、8和12 h监测瘤胃pH值，在早晚饲喂前收集奶样，晨饲6 h后采集颈静脉血，用于测定脂肪酸及代谢物组成。基于奶牛瘤胃平均pH值高低，将奶牛分为SARA易感组（SUS，瘤胃pH=5.76，n=4）和SARA耐受组（TOL，瘤胃pH=6.10，n=4）。脂肪酸测定结果分析显示，与TOL组相比，SUS组奶牛血液及乳中的碳链长度≤C16的脂肪酸含量显著增高（P<0.05），而>C16的脂肪酸的含量显著降低（P<0.05），乳中饱和脂肪酸及单不饱和脂肪酸含量均显著降低（P<0.05）。血浆代谢组结果显示， SUS组奶牛血浆中L-苯丙酮酸水平显著降低（P<0.05），而MG（18：0/0：0/0：0）、9-HODE、12（13） Ep-9-KODE、烟酰胺、异戊基肉碱、磷酸肌酸和L-谷氨酸水平显著升高（P<0.05）。乳代谢组分析结果显示，与TOL组比较，SUS组奶牛乳中的1-硬脂酰磷酸甘油丝氨酸和鞘氨醇水平显著升高（P<0.05），而甘油磷酰基乙醇胺、3-磷酸甘油和乳清酸等其他14个差异代谢物水平显著降低（P<0.05），这些差异代谢物主要涉及甘油磷脂代谢、甘油脂代谢及泛酸与辅酶A代谢等代谢途径。综上所述，SARA耐受性不同的奶牛的血浆和乳中脂肪酸及代谢物组成存在较大差异，SUS组奶牛血浆中氨基酸代谢活动增加，乳腺的乳脂从头合成能力较强，而从血液中摄取长链脂肪酸能力减弱，与此同时，易感奶牛乳中磷脂、乳清酸等营养物质水平下降，乳品质下降。     

Culling of dairy cows. Part II. Effects of diseases and reproductive performance on culling in Finnish Ayrshire cows

The effects of 15 diseases and reproductive performance on culling were studied in 39 727 Finnish Ayrshire cows that calved in 1993 and were followed until culling or next calving. Survival analysis, using the Cox proportional hazards model, was performed with diseases and pregnancy status as time-dependent covariates. Parity, calving season and herd were included as covariates in every model. The effect of the number of inseminations was also studied.

The farmer's knowledge of the cow's pregnancy status had a significant effect on culling. It varied according to the stage of lactation a cow was in; the earlier the farmer knew a cow was pregnant, the smaller was the risk of culling. If a cow had not been inseminated at all, her risk of culling was 10 times higher than if she was inseminated once. If a cow was inseminated more than once, she had a slightly lower risk of being culled than a cow inseminated only once. The effect of parity decreased when pregnancy status and number of inseminations were added to the model, indicating that part of the parity effect was accounted for by reproductive performance. Including diseases in the model with pregnancy status and the number of inseminations did not change the effects of reproductive performance on culling.

Mastitis, teat injuries and lameness had the greatest effect on culling (whether adjusted for reproductive performance or not), increasing the risk of culling, followed by anestrus, ovarian cysts and milk fever. In general, the effects of diseases decreased when reproductive performance was also accounted for in the model. When pregnancy status was included in the model, the effects of anestrus and ovarian cysts became slightly more protective, but when the number of inseminations was also considered, they became non-significant at the beginning of lactation and they increased the risk of culling at the end of lactation.

Sensitivity analysis, which was run to evaluate the effects of our censoring mechanism on the results, indicated that the censoring times (i.e., the time of next calving) were not fully independent of the event (culling) times; the effects of the diseases and pregnancy status at the very end of the lactation changed slightly from the original model.     

日粮蛋白质水平对奶牛产后卵巢机能恢复及生殖激素的影响

[目的]本试验旨在探讨不同蛋白质水平日粮对奶牛产后卵巢机能恢复及生殖激素的影响,以确定奶牛日粮适宜蛋白质水平.[方法]采用单因素对比实验设计,根据生理状况和泌乳性能相近原则将72头中国荷斯坦牛,随机分成3组,每组24头,分别在围产期和泌乳盛期饲喂9.8%(A1)和13.8%(A2)、12.6%(B1)和16.2%(B2...     

Chemical and amino acid composition of colostrum and mature milk differ only slightly in mink (Mustela vison)

To determine differences in chemical composition between colostrum and mature milk in mink, milk samples were collected from 12 dams as close to the end of parturition as possible (n = 12), and at 24 h (n = 3), 48 h (n = 3) and 1 week (n = 12) postpartum. The milk samples were analysed for dry matter (DM), ash, crude protein, fat, carbohydrate, and amino acid composition. The DM content was higher (p < 0.05) in milk sampled at parturition than at 24 and 48 h postpartum. Also, the crude protein content decreased (p < 0.05) after the first 24 h postpartum. However, the fat, carbohydrate and ash contents did not change (p > 0.05) during the first week of lactation. The proportion of essential amino acids tended to decrease during the first 24 h postpartum. During the first week of lactation, the phenylalanine and tyrosine contents decreased while the cysteine content increased. However, in general, the differences between colostrum and mature milk were less pronounced in the mink than in many other species. Thus, colostrum seems to be of little importance in the mink in conferring passive immunity and hence for kit survival.     

Response to intensity of reproduction in mouse lines resistant or susceptible to fescue toxicosis

Our objective was to examine whether mouse lines divergently selected for response to fescue toxicosis differed in the impact of increasing reproductive intensity on growth, final weight or first and second parity reproduction. Resistant (R) and susceptible (S) females were never mated (NR), mated only once (low reproduction, LR), mated after their first litter was weaned (moderate reproduction, MR) or paired continuously with a male (high reproduction, HR), allowing concurrent pregnancy and lactation. Final weight was significantly higher in mated than in not mated females (31.6 ± 0.6, 35.9 ± 0.6, 36.8 ± 0.6 and 37.2 ± 0.5 g for NR, LR, MR and HR females respectively), but the effect of increasing reproductive intensity was similar in both lines. Neither genetic line, reproductive treatment (LR and MR versus HR) nor their interaction affected first parity traits of dams or pups. In second parity, S dams produced larger litters at birth and weaning and heavier litters at birth than R dams, and MR dams produced more pups and heavier litters than HR dams. As with first litters, however, line by reproductive treatment interactions were not significant or important. Concurrent pregnancy and lactation (the HR treatment) had a similar dampening impact on the expected increase in litter size between first and second parity of both lines. Thus, lines divergently selected for toxicosis response did not differ significantly in the impact of increasing reproductive intensity on dam or pup growth, reproductive output through two parities or mature size. This conclusion should not be generalized. Selection responses in livestock should be monitored to ensure that improvement in one trait does not lead to deterioration in others.     

Comparison of amino acid profiles between rats subjected to forced running and voluntary running exercises

It has been suspected that in comparison with glucose or fatty acids, the levels of amino acids may readily change with different forms of exercise. In the present study, we measured the concentrations of amino acids, glucose, triglycerides, total protein and total cholesterol in the blood and/or cerebrospinal fluid (CSF) of rats subjected to forced running exercise on a treadmill, and voluntary running exercise using a wheel, with a constant running distance of 440 m. Rats that performed no running and rats subjected to immobilization stress were used as controls. We observed a few significant changes in the levels of plasma glucose, triglycerides, total protein and total cholesterol in all groups. Whereas, plasma amino acid levels were significantly changed by exercise and stress, especially during the light period. The plasma levels of many amino acids were specifically increased by forced running; some were decreased by immobilization stress. Few amino acids showed similar changes in their levels as a result of voluntary running. In addition, there was a significant difference in the degree of amino acid imbalance between blood and CSF. These results provide the first information on changes in levels of amino acids in plasma and CSF resulting from forced and voluntary exercises.