氟节胺对柑橘控梢保果效应的研究

为研究125克/升氟节胺乳油对柑橘的控梢保果作用,连续两年在柑橘树春梢老熟夏梢未抽时喷施不同浓度的125克/升氟节胺乳油。结果显示：125克/升氟节胺乳油能够明显控制和抑制柑橘夏梢的萌发和生长,与空白对照相比,夏梢的控制率和抑制率分别达到了21.8% ~ 51.6%和32.4% ~ 46.5%,座果率也提高了49.1% ~96.9%,增产5.8%以上。125克/升氟节胺乳油对柑橘有一定的保果和增产作用,推荐使用剂量为有效成分125~166 mg/kg,稀释倍数为1000~750倍,于柑橘树春梢老熟夏梢未抽时喷施1次。     

喷施硫酸锌对紫花苜蓿草产量和品质的影响

采用叶面喷施的的方法研究了不同施锌水平200,500和800mg／kg对紫花苜蓿（Medicaco sativa）干草产量及品质影响。结果表明：喷施硫酸锌显著（P〈0．05）提高苜蓿草产量,其中施锌量为500mg／kg的处理产量最高。适量的锌水平可以显著提高粗蛋白含量,施锌量为500mg／kg时,可以显著提高紫花苜蓿粗脂肪、粗纤维、磷的含量,对粗灰分含量影响不大。喷施不同浓度Zn处理,除第1茬外,苜蓿中的钙含量有增加趋势。营养物质的年积累量均以施锌浓度为500mg／kg时达到最高。     

S-诱抗素对沙糖桔花芽分化、产量及果实品质的影响

本试验研究S-诱抗素对沙糖桔Citrus reticulata Blanco cv. ‘Shatangju’的花芽分化、产量及果实品质的影响,为沙糖桔优质高产栽培技术的优化提供新的依据,也为该药剂推广至其他柑橘类果树提供技术参考。在2012-2015年间共进行两次田间试验,每次试验周期为两年。在沙糖桔树秋梢老熟、果实采收结束、春梢萌动三个时期用不同浓度1%S-诱抗素可溶粉剂进行整株喷施处理,处理浓度为1.67 mg/kg、2.50 mg/kg、3.30 mg/kg、5.00 mg/kg,1.4%复硝酚钠水剂(2.50 mg/kg)与清水作对照。观测试验对象花芽和果实的相关生理指标进行分析。经不同浓度S-诱抗素处理的沙糖桔,花芽分化、产量的各项指标数值均显著高于空白对照,其中单株产量和增产幅度随处理浓度的升高而增大。在试验浓度范围内,S-诱抗素还可以明显改善果实品质,不产生药害。当处理浓度为3.30 mg/kg时,花芽数、开花数、坐果率达到同期最大值。为使S-诱抗素处理达到最佳效果,同时考虑实际应用过程中的复杂因素,建议田间施用量以2.5-3.3 mg/kg为宜。     

喷施不同钙肥对蓝莓产量、果品及贮藏性的影响

通过田间试验探讨糖醇螯合钙与硝酸钙对蓝莓产量、果实品质及贮藏性的影响,为钙肥在蓝莓生产中的合理应用提供科学理论依据。研究结果表明：与对照相比,喷施Ca2+浓度140mg/L与175mg/L的糖醇螯合钙,能显著提高蓝莓株产,增加蓝莓单果重、纵横径及果实硬度,显著增加了果实可溶性固形物、可溶性糖含量,显著降低了果实可滴定酸的含量及霉变率,而喷施Ca2+浓度70mg/L的糖醇螯合钙,除硬度、可溶性固形物含量显著高于对照,可滴定酸含量、霉变率显著低于对照外,在株产、单果重、纵横径及可溶性糖含量上与对照间差异不显著;喷施不同钙浓度的硝酸钙,蓝莓果实产量、品质及贮藏性未得到提高或改善,与对照间差异不显著,反而过量的硝酸钙造成了蓝莓单果重及果实纵径的降低。综合蓝莓株产、品质及贮藏性,蓝莓生产中推荐喷施糖醇螯合钙,不建议喷施硝酸钙作为钙肥,推荐喷施Ca2+浓度140~175mg/L。     

叶面喷施烯效唑对大豆产量及品质的影响

通过分枝期和初花期对大豆喷施烯效唑试验,研究了施药时期和施药浓度对大豆产量和品质的影响。结果表明,经烯效唑处理的大豆植株表现为株高降低,茎粗增粗,分枝数增多,产量增加;蛋白质含量、蛋白质产量和粗脂肪产量均高于对照(除A2B1),均以分枝期喷施75mg/kg烯效唑最高,分别比对照提高5.05%,56.59%和59.15%。可见,分枝期喷施75mg/kg的烯效唑最有利于产量形成,蛋白质和粗脂肪的积累。     

缩节胺、比久对紫花苜蓿种子产量的影响

为了探究植物生长调节剂对紫花苜蓿种子产量的影响,试验采用随机区组方法,以龙牧801苜蓿为研究对象,采用缩节胺(80,160,240 mg/L)、比久(3 000,5 000,7 000 mg/L)两种植物生长调节剂分别于现蕾期和盛花期两次对紫花苜蓿种子田进行叶面喷施,在成熟期测定不同浓度对紫花苜蓿种子产量及构成因子的影响,并进行相关性分析和逐步回归分析。结果表明：喷施缩节胺、比久(除7 000 mg/L)后种子产量均显著高于对照(P<0.05)。各产量构成因子与种子产量均呈正相关,喷施缩节胺处理每平方米生殖枝数与种子产量呈显著正相关(P<0.05)。喷施比久处理每个生殖枝的结荚花序数与种子产量呈极显著正相关(P<0.01),每个荚果的种子数与种子产量呈显著正相关(P<0.05)。喷施缩节胺处理种子产量与各产量构成因子的逐步回归方程为Y=2.043 9+0.216 5X₁(Y为种子产量,X₁为每平方米生殖枝数)。喷施比久处理种子产量与各产量构成因子的逐步回归方程为Y=17.175 3+0.049 1X₁     

不同浓度矮壮素对黑麦抗倒伏性和种子产量的影响

为探寻使黑麦(Secale cereale)抗倒伏性增强,并能获得较高种子产量的矮壮素喷施浓度,本研究通过在黑麦拔节期对其喷施不同浓度矮壮素(0,0.1%,0.2%,0.3%,0.4%),研究其对黑麦抗倒伏性和种子产量的影响。结果表明,矮壮素喷施浓度为0.3%和0.4%时,黑麦株高降低约30cm,节间缩短,基部第2节间的外径增粗,抗折力增强,钾和可溶性总糖含量增加,氮含量减少,抗倒伏指数增大,同时种子产量显著高于对照(不喷施矮壮素),增产1 500kg·hm-2(P0.05)。黑麦种子产量与株高和氮含量极显著负相关(P0.01),与基部第2节间的外径、抗折力、抗倒伏指数、钾含量等极显著正相关,和第1节间长显著负相关,说明增强黑麦抗倒性有利于提高其种子产量。0.1%和0.2%浓度的矮壮素对黑麦的抗倒伏性以及种子产量等性状无显著影响(P0.05)。从经济效益和环保的角度出发,喷施浓度为0.3%的矮壮素既可以增加产量又可以减少矮壮素用量,为黑麦进行种子生产的适宜用量。本研究在一定程度上解决了黑麦由于倒伏引起的种子产量低的问题,为黑麦种子生产提供了理论依据。     

喷施聚天门冬氨酸对不同品种紫花苜蓿产量及品质的影响

采用叶面喷施的方法研究了聚天门冬氨酸(PASP)5个作用浓度20、40、60、801、00 mg/kg对3个紫花苜蓿品种产量及品质的影响。结果表明:喷施PASP对不同品种1年3茬次的产量和品质具有不同影响。3个紫花苜蓿品种年产量均以PASP为20 mg/kg处理最高,且都显著(P0.05)高于对照;PASP浓度为20 mg/kg可以显著提高阿尔冈金和甘农3号的株高,PASP为40 mg/kg可以显著提高金皇后的株高;喷施PASP对紫花苜蓿营养物质含量的影响不同,PASP 60 mg/kg能显著提高阿尔冈金及甘农3号的粗蛋白、磷含量;PASP 40 mg/kg能显著提高阿尔冈金、甘农3号的粗脂肪及粗灰分含量;PASP 80 mg/kg处理能显著提高甘农3号的钾含量及金皇后的磷含量;对金皇后脂肪及灰分具有显著作用的处理是60 mg/kg。     

植物生长延缓剂对杂交狗牙根草坪草生长特性的影响

研究了烯效唑、矮壮素、缩节胺、比久4种植物生长延缓剂对暖季型草坪草交杂狗牙根生长特性的影响.结果表明:烯效唑处理狗牙根的最适浓度为50～100 mg/L,用药量以200 mL/m2为宜,使狗牙根生长速度减慢,节间缩短,叶片加宽,叶绿素含量增加,叶色加深.100～400 mg/L浓度的矮壮素和缩节胺及500～2 000 mg/L浓度的比久处理能不同程度地抑制狗牙根的生长,抑制作用随浓度增加而加强,但与对照相比差异不显著,对狗牙根密度、叶色、叶绿素、叶长、叶宽等品质无显著影响.     

外源喷施植物生长调节剂对香蕉产量和外观品质的影响

本文主要探究喷施植物生长调节剂对香蕉产量和外观品质的影响。在香蕉反梳时,按照一定比例喷施胺鲜酯、赤霉素和复硝酚钠+赤霉素复配液,对香蕉果皮色差、果实特征、果实中大量元素累积量以及产量等指标进行动态跟踪。结果表明,与对照相比,喷施赤霉素和复硝酚钠+赤霉素复配液,可以显著提高香蕉果皮亮度、果指长和果实中NK养分累积;喷施胺鲜酯、赤霉素以及复硝酚钠+赤霉素复配液分别比对照增产4.60、7.70和12.33 kg/plant。综合比较,复硝酚钠+赤霉素复配液处理的效果明显好于胺鲜酯和赤霉素处理。研究表明在香蕉反梳时,可以通过硝酚钠+赤霉素复配液来提高香蕉产量和外观品质。     

几种农药对荔枝蒂蛀虫的室内毒力和田间防效

目前,荔枝蒂蛀虫的防治主要以化学防治为主,但由于药剂的不规范使用,导致施药次数增加,防治难度加大。为筛选对荔枝蒂蛀虫有高效防控作用的药剂,本研究采用药膜法测定了4种药剂对荔枝蒂蛀虫的室内毒力,并进行了田间效果评价。研究结果表明：4种药剂中1.5%甲氨基阿维菌素苯甲酸盐乳油对荔枝蒂蛀虫成虫的LC50为7.34 mg/kg,具有较高的毒力,5%氯虫苯甲酰胺悬浮剂、13%高效氯氰菊酯?三唑磷乳油和15%高效氯氰菊酯?毒死蜱乳油的毒力则相对较差。田间药效试验中,以上4种药剂对荔枝蒂蛀虫的田间防效均在90%以上。本研究表明,1.5%甲氨基阿维菌素苯甲酸盐乳油、5%氯虫苯甲酰胺悬浮剂、13%高效氯氰菊酯?三唑磷乳油和15%高效氯氰菊酯?毒死蜱乳油对荔枝蒂蛀虫具有较好的防治效果,可在荔枝产区继续推广使用。     

镉胁迫对紫花苜蓿镉吸收特征及根系形态影响

采用盆栽模拟方法,研究了4种镉(Cd)浓度(0,10,25,50 mg/kg)下紫花苜蓿对Cd吸收特征及根系形态的变化特征。结果发现,随着镉胁迫加剧,紫花苜蓿地上生物量、根系生物量、根系总长度、根平均直径、根表面积、根系体积、根尖数和分枝数均显著下降(P<0.05),地上部生物量分别为对照的87.8%,56.5%,14.3%,根系生物量分别为96.1%,63.3%,16.2%;不同部位镉吸收量表现为细根>地上部>粗根,三者均随着处理浓度增加而显著提高,细根镉含量与地上部镉含量呈显著正相关;地上部最高镉积累量出现在25 mg/kg处理中,达到7.715 μg/株;不同径级根系的总根长、根表面积、根体积随镉浓度增加呈下降趋势,根径<0.5 mm根系占总根系比例呈增加趋势。研究表明,紫花苜蓿可用于低Cd污染场地的植被恢复,其根系对Cd胁迫的响应特征呈现侧根产生—根受损的动态平衡现象。     

不同杀虫剂对井上蛀果斑螟卵的触杀作用

为了解不同杀虫剂对井上蛀果斑螟卵的触杀作用,采用浸渍法测定了辛硫磷、丙溴磷、乙酰甲胺磷、高效氯氟氢菊酯、杀虫双、除虫脲、噻嗪酮、阿维.哒螨灵、吡虫.三唑磷等9种药剂对井上蛀果斑螟卵的触杀效果。结果表明：2.5%高效氯氟氢菊酯EC 600倍液,对井上蛀果斑螟卵的触杀效果最高,校正死亡率达98.67％;40%辛硫磷EC 250和500倍液、30％乙酰甲胺磷EC 300倍液、37%噻嗪酮SC 250倍液、20％吡虫.三唑磷EC 150倍液处理,校正死亡率均在90%以上。此外,40%辛硫磷EC 1 000和1 500倍液、40%丙溴磷EC 2 000和2 500倍液、30％乙酰甲胺磷EC 600倍液、2.5%高效氯氟氰菊酯EC 800倍液、25%杀虫双AS 100和150倍液、25%除虫脲2 500倍液、8％阿维.哒螨灵EC 1 500倍液和20％吡虫.三唑磷EC 150倍液的触杀效果均高于80％。综合试验结果考虑,防治井上蛀果斑螟,可使用40％辛硫磷EC 500~1000倍液、30％乙酰甲胺磷EC 300~600倍液、2.5%高效氯氟氰菊酯EC 600~800倍液、37% 噻嗪酮SC 250倍液和20％吡虫.三唑磷EC 100~150倍液对该虫的卵期进行防治。     

寒冷季节光照制度对育肥猪生长性能、肉品质及血清生化指标的影响

文章旨在评估寒冷季节延长光照时间对育肥猪生长性能、肉品质及血清生化指标的影响.试验将15周龄、平均体重为(54.26±0.17)kg的352头三元商品肥猪随机分为2组,每组176头,每组8个重复.整个试验期间(15～24?w),外界环境温度为-10℃～-5℃,对照组采用常规光照模式(光照12?h,黑暗12?h),处理组...     

Effects of implants on daily gains of steers wintered on dormant native tallgrass prairie, subsequent performance, and carcass characteristics

Fall-weaned crossbred steer calves (n = 300; 184 +/- 2.9 kg) received either no implant (Control) or were implanted with Synovex-C (SC = 10 mg estradiol benzoate + 100 mg progesterone), Synovex-S (SS = 20 mg estradiol benzoate + 200 mg progesterone), or Revalor-G (RG = 8 mg estradiol-17beta + 40 mg trenbolone acetate) to determine the effects of implants on weight gain during winter grazing on dormant tallgrass prairie, subsequent grazing and finishing performance, and carcass characteristics. Steers grazed two dormant tallgrass prairie pastures from October 16, 1996, until March 29, 1997 (164 d), and received 1.36 kg/d of a 25% CP supplement that supplied 100 mg of monensin/steer. Following winter grazing, all steers were implanted with Ralgro (36 mg zeranol) and grazed a common tallgrass prairie pasture until July 17 (110 d). After summer grazing, all steers were implanted with Revalor-S (24 mg estradiol-17beta + 120 mg trenbolone acetate), and winter implant treatment groups were equally allotted to four feedlot pens. Steers were harvested November 17, 1997, after a 123-d finishing period. Daily gains during the winter grazing phase averaged .28, .32, .32, or .35 kg/d, respectively, for Control, SC, SS, or RG steers and were greater (P < .01) for implanted steers than for Controls. Summer daily gains were similar (1.05 +/- .016 kg/d; P > or = .61) for all treatment groups. Feedlot daily gains were also similar (1.67 +/- .034 kg/d; P > or = .21), with implanted steers weighing 14 kg more than Control steers (P = .05) at harvest, despite similar management during summer grazing and feedlot phases. Control steers tended (P = .06) to have lower yield grades. There were no differences (P = .99) in marbling between implanted and nonimplanted steers. Steers implanted during the wintering phase had increased skeletal and overall (P < .01) carcass maturities compared with nonimplanted steers, which resulted in more "B" and "C" maturity carcasses. Because carcass maturity score affects quality grade, the increased maturities of implanted steers resulted in a $9.04 decrease in carcass value/100 kg (P < .01) compared with Controls. The results of this study indicate that growth-promoting implants are efficacious for cattle wintered on dormant native range despite low daily gains. This increased weight is maintained through the summer grazing and feedlot phases; however, the benefit of the increased weight may be offset by decreased carcass quality grade and value due to increased carcass maturity.     

酿酒酵母培养物对817肉仔鸡生长性能、养分表观利用率及肠道菌群的影响

本试验旨在探讨酿酒酵母培养物(SC)对817肉仔鸡生长性能、养分表观利用率及肠道菌群的影响。试验选取1日龄体重相近的817肉仔鸡600只,随机分为5组,每组6个重复,每个重复20只。对照组饲喂基础饲粮,抗生素组在基础饲粮中添加20 mg/kg硫酸黏杆菌素+2.6 mg/kg黄霉素,试验Ⅰ、Ⅱ、Ⅲ组分别在基础饲粮中添加2 500、5 000、7 500 mg/kg SC,试验期为60 d。结果显示:1)1~21日龄,试验Ⅱ、Ⅲ组的平均日增重(ADG)、平均日采食量(ADFI)均显著高于对照组(P0.05),与抗生素组无显著差异(P0.05);在22~60日龄和1~60日龄2个阶段,试验Ⅱ组的ADG显著高于对照组(P0.05),ADFI显著高于抗生素组(P0.05);22~60日龄,3个试验组的料重比和死亡率较对照组差异均不显著(P0.05),但在1~60日龄有下降趋势(0.05≤P0.10)。2)试验Ⅱ、Ⅲ组较对照组显著提高了总磷的表观利用率(P0.05);各组粗蛋白质、钙的表观利用率无显著差异(P0.05)。3)与对照组相比,试验Ⅰ组盲肠中大肠杆菌的数量显著降低(P0.05),与抗生素组无显著差异(P0.05);试验Ⅱ组盲肠中乳酸菌数量和试验Ⅲ组空肠中双歧杆菌数量均显著高于对照组和抗生素组(P0.05)。由此可见,饲粮中添加适宜水平的SC能增加817肉仔鸡ADFI和ADG,降低料重比,增强对饲粮中总磷的利用率,促进乳酸菌、双歧杆菌的增殖,抑制大肠杆菌的增殖;当SC添加水平为5 000 mg/kg时,对动物的促生长效果最佳,优于抗生素。     

Effects of nickel supply on the fattening performance and several biochemical parameters of broiler chickens and rabbits

Broiler chicken and rabbit experiments were carried out to study the effects of nickel (Ni) supplementation on growth performance and Ni metabolism. ROSS cockerels and New Zealand White female rabbits were fed a diet containing Ni in concentrations of 0, 50 and 500 mg/kg in dry matter (DM). Dietary supplementation of 50 mg Ni/kg slightly improved the body weight gain (BWG) and had a beneficial effect on the feed conversion efficiency (FCE) in broiler chickens. However, Ni added at a level of 500 mg/kg significantly (P < 0.05) reduced the BWG by 10% and resulted in significantly (P < 0.05) worse (2.3 +/- 0.2 kg/kg) FCE. The relative weight of the liver in cockerels was significantly (P < 0.05) decreased by Ni as compared to the control group (1.7 and 2.1% vs. 2.6%). The activity of AST and CHE enzymes was increased insignificantly by dietary supplementation of 500 mg Ni/kg, indicating damage of the liver parenchyma. The results of serum biochemistry were confirmed by a mild or moderate form of pathological focal fatty infiltration of the liver in broilers. Supplemental Ni of 50 mg/kg concentration resulted in non-significantly increased BWG in rabbits. Ni added to the diet at a level of 500 mg/kg reduced the digestibility of crude protein by 3-4% and that of crude fibre by 20-25% in rabbits. Approx. 98% of the ingested Ni was lost from the body via the faeces, 0.5-1.5% via the urine and approx. 1% was incorporated into the organs of rabbits. As a result of dietary supplementation of 50 and 500 mg Ni/kg, Ni accumulated in the kidneys (4.9 +/- 0.5 and 17.1 +/- 3.1 vs. 1.9 +/- 0.3 mg/kg DM), ribs (10.3 +/- 0.4 and 10.4 +/- 0.6 vs. 9.1 +/- 0.6 mg/kg DM), heart (1.4 +/- 0.2 and 2.5 +/- 0.4 vs. 1.0 +/- 0.1 mg/kg DM) and liver (1.3 +/- 0.1 and 2.2 +/- 0.2 vs. 0.9 +/- 0.05 mg/kg DM), as compared to the control animals. It can be stated that supplementation of the diet with 50 mg Ni/kg had slight but non-significant beneficial effects on the growth performance of broiler chickens and rabbits.     

苜蓿多糖对夏季高温环境下蛋鸡生产性能及蛋品质的影响

本试验旨在研究夏季高温环境下在饲粮中添加苜蓿多糖对蛋鸡生产性能及蛋品质的影响。将540只156日龄海兰褐蛋鸡随机分成6组,每组6个重复,每个重复15只鸡。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加250、500、1 000、2 000和4 000 mg/kg苜蓿多糖的试验饲粮。试验期为6周。结果显示:与对照组相比,1)饲粮中添加不同水平苜蓿多糖对平均蛋重、平均日采食量、不合格蛋率和死淘率均无显著影响(P0.05),而添加500、1 000和4 000 mg/kg苜蓿多糖显著提高了蛋鸡的产蛋率(P0.05),添加500、1 000、2 000和4 000 mg/kg苜蓿多糖显著降低了料蛋比(P0.05)。2)饲粮中添加不同水平苜蓿多糖对蛋白高度和哈夫单位均无显著影响(P0.05);250 mg/kg苜蓿多糖添加组第4和6周末的蛋黄颜色显著提高(P0.05);500 mg/kg苜蓿多糖添加组第6周末的蛋形指数显著降低(P0.05),第1、4和6周末的蛋黄颜色显著提高(P0.05);1 000 mg/kg苜蓿多糖添加组第4和6周末的蛋壳颜色显著加深(P0.05),第1、2和4周末的蛋壳强度和蛋壳厚度显著提高(P0.05),第1和6周末的蛋形指数显著降低(P0.05),第1、2、4和6周末的蛋黄颜色显著提高(P0.05);2 000 mg/kg苜蓿多糖添加组第1和4周末的蛋壳厚度显著提高(P0.05),第6周末的蛋形指数显著降低(P0.05),第1、4和6周末的蛋黄颜色显著提高(P0.05);4 000 mg/kg苜蓿多糖添加组第4周末的蛋壳颜色显著加深(P0.05)且蛋壳强度显著提高(P0.05),第1和4周末的蛋壳厚度显著提高(P0.05),第6周末的蛋形指数显著降低(P0.05),第1、4和6周末的蛋黄颜色显著提高(P0.05)。结果表明,夏季高温环境下,在饲粮中添加适量的苜蓿多糖可以有效缓解蛋鸡的热应激,提高蛋鸡的生产性能,改善蛋品质,且适宜添加量为1 000 mg/kg。     

Dietary L-carnitine increases plasma insulin-like growth factor-I concentration in chicks fed a diet with adequate dietary protein level

1. The effect of L-carnitine supplemented into experimental diets with varying dietary protein concentrations (50, 200 and 400 g/kg) on body weight gain and plasma insulin-like growth factor-I (IGF-I) concentration in chicks was examined. 2. Dietary L-carnitine supplementation provided 0, 200, 500 and 1000 mg/kg. Chicks were given the diet ad libitum for 10 d. 3. When L-carnitine was provided as 500 or 1000 mg/kg, body weight gain was significantly improved in birds receiving the 200 and 400 g protein/kg diets. 4. There was an interaction between dietary L-carnitine and protein content on plasma IGF-I concentration. L-carnitine supplementation had little influence on plasma IGF-I concentrations in birds receiving the low protein (50 g/kg) diet. When dietary L-carnitine concentrations were increased from 0 to 1000 mg/kg in the adequate protein (200 g/kg) diet, plasma IGF-I concentrations were also increased. However, when dietary L-carnitine content was more than 500 mg/kg in the 400 g/kg protein group, plasma IGF-I concentration decreased with increasing dietary L-carnitine content. 5. Body weight change correlated significantly with the alteration in plasma IGF-I concentrations in chicks given diets with adequate dietary protein. 6. In conclusion, the improvement in body weight gain caused by dietary L-carnitine supplementation was achieved when chicks were given their dietary protein requirement, which may be partially explained by an increase in plasma IGF-I concentration.