3种黄酮类植物雌激素对42日龄樱桃谷鸭屠宰性能的影响

本试验以SM3樱桃谷鸭为研究对象,进行了添喂大豆异黄酮、葛根异黄酮和葛根素对樱桃谷鸭屠宰性能的研究。主要研究异黄酮42日龄樱桃谷鸭屠宰性能的影响。试验选用健康的1日龄SM3樱桃谷鸭160只,按初始体重随机分为4组,每组4个重复,每个重复5只,采用4×2两因素析因试验设计。试验喂给基础日粮和基础日粮 葛根异黄酮10mg/kg、葛根素10mg/kg、大豆异黄酮10mg/kg;各组试鸭均在基础日粮预饲一周后喂给各添加剂,并于42日龄屠宰对其屠宰性能的相关指标进行分析。结果表明:母鸭屠宰率、半净膛率、全净膛率和瘦肉率都高于公鸭(P>0.05),并以葛根异黄酮组母鸭的效果最好。葛根素使后期胸肌率、腿肌率和瘦肉率分别比对照提高了2.73%、2.61%、2.56%,葛根异黄酮腿肌率和瘦肉率分别提高了5.54%和1.23%。     

葛根素对樱桃谷鸭肝脏指数、肝脂率和肝脏MDH活力的影响

采用1日龄樱桃谷鸭160羽,随机分为4个处理组,每组8个重复,每个重复5羽,公母各半.1组饲喂基础日粮,2、3、4组分别饲喂基础日粮+5、10、15mg/kg葛根素,试验为期42 d.结果表明:剂量因子对21和42日龄樱桃谷鸭肝脏指数和肝脂率的影响均不显著(P＞0.05),21日龄5 mg/kg和10 mg/kgMDH的活力低于对照组,但差异不显著(P＞0.05).剂量和性别各组和的差异均不显著(P＞0.05),但42日龄的肝脂率有降低的趋势(P=0.098),MDH活力有升高的趋势(P=0.182).     

不同饲料加工工艺及维生素添加量对肉仔鸡生长性能和屠宰性能的影响

本试验旨在研究不同饲料加工工艺及维生素添加量对肉仔鸡生长性能和屠宰性能的影响。试验选用480只1日龄体重接近的白羽爱拔益加肉仔鸡,随机分为4组,每组8个重复,每个重复20只鸡。对照组(A组)饲粮采用普通饲料加工工艺,配方中添加正常剂量的复合维生素[前期(1~21日龄)350 mg/kg、后期(22~42日龄)250 mg/kg];试验组饲粮采用高效调质低温制粒工艺,减少配方中复合维生素添加量(B组:前期280 mg/kg、后期200 mg/kg;C组:前期224 mg/kg、后期160 mg/kg;D组:前期180 mg/kg、后期128 mg/kg)。试验期42 d。结果表明:试验前期,A组肉仔鸡饲料淀粉糊化度显著低于B组、C组和D组(P0.05)。试验后期,A组肉仔鸡饲料颗粒耐久性指数显著低于B组、C组和D组(P0.05)。试验前期、后期和全期(1~42日龄),各组肉仔鸡的末重、平均日增重、平均日采食量和料重比均差异不显著(P0.05)。各组肉仔鸡的腿重/屠宰重、胸肉重/屠宰重、心脏重/屠宰重、肝脏重/屠宰重、脾脏重/屠宰重、肌胃重/屠宰重、腺胃重/屠宰重均差异不显著(P0.05),各组十二指肠、空肠和回肠的长度及重量均差异不显著(P0.05)。由此可见,肉仔鸡饲粮采用高效调质低温制粒工艺,颗粒饲料加工质量优于普通饲料加工工艺,且饲料配方中减少维生素添加量对肉仔鸡生长性能和屠宰性能与普通饲料加工工艺无显著差异,即该工艺可节约维生素使用量。     

大豆异黄酮对肉仔鸡免疫功能的影响

100只6周龄的AA肉仔鸡随机分为4组,每组5个重复,日粮中分别添加0mg／kg、3mg／kg、6mg／kg、9mg／kg的大豆异黄酮,以研究对肉仔鸡免疫功能的影响。试验结果表明,肉鸡日粮中添加大豆异黄酮对内仔鸡的肝重／体重,脾重／体重,法氏囊重／体重,胸腺重／体重,影响均不显著（P〉0．05）,日粮中添加大豆黄酮有使法氏囊／体重增加的趋势,但统计上不显著。42日龄的屠宰试验中,试验Ⅰ组白细胞数与其他各组差异显著（P〈0．05）。     

日粮中添加微生态制剂对樱桃谷鸭生产性能的影响

试验旨在研究日粮添加不同水平微生态制剂对樱桃谷鸭生产性能的影响,确定最佳添加水平。选用1日龄樱桃谷鸭750只,随机分成5个组(试验Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组,Ⅴ组为对照组),每组设3个重复,每个重复50只。分别在基础日粮中添加500、1000、1500、2000和0 mg/kg微生态制剂,饲养至42日龄。结果表明,添加1000和1500 mg/kg的微生态制剂促生长效果显著高于对照组(P<0.05);添加1000 mg/kg微生态制剂的肉鸭全程料重比最佳;添加500 mg/kg的微生态制剂组对肉鸭增重不明显;添加2000 mg/kg的微生态制剂组优于对照组和500 mg/kg添加组,但差异不显著(P>0.05)。因此,日粮微生态制剂能促进樱桃谷肉鸭的增重、降低料重比,从而提高其生长性能、产肉性能及养殖效益,1000 mg/kg微生态制剂能取得最佳料重比和经济效益,1500 mg/kg微生态制剂能取得最佳产肉性能,由此可知,添加1000 mg/kg微生态制剂为最佳添加水平。     

辣椒碱对樱桃谷肉鸭生长性能、肉品质和抗氧化功能的影响

试验旨在研究辣椒碱对樱桃谷肉鸭生长性能、肉品质、肌肉抗氧化功能的影响。试验选择1日龄樱桃谷鸭192只,随机分为3组,每组8个重复,每个重复8只。分别饲喂基础日粮(对照组)、基础日粮+100 mg/kg辣椒碱(试验Ⅰ组)、基础日粮+300 mg/kg辣椒碱(试验Ⅱ组),试验期为42 d。结果显示:与对照组相比,添加300 mg/kg辣椒碱能显著提高樱桃谷肉鸭的采食量(P0.05)、日增重(P0.05),改善樱桃谷肉鸭的生长性能;显著降低14日龄樱桃谷鸭血清中葡萄糖、14日龄与42日龄胆固醇浓度(P0.05);添加辣椒碱能显著降低樱桃谷肉鸭胸肌24 h亮度值、24 h滴水损失和蒸煮损失(P0.05),显著提高24 h红度值(P0.05);此外,辣椒碱能显著提高腿肌中T-AOC能力和SOD活性(P0.05),以及胸肌中T-AOC能力和CAT活性(P0.05),显著提高樱桃谷肉鸭胸肌和腿肌的Nrf2和NQO-1 m RNA表达量(P0.05)。综上所述,饲粮中添加辣椒碱能提高樱桃谷肉鸭生长性能,改善肉品质,提高机体抗氧化能力。     

刺五加多糖对樱桃谷鸭生长性能和免疫功能的影响

文章旨在研究刺五加多糖对樱桃谷鸭生产性能和免疫功能的影响。试验选用体况匀称的240只1日龄健康樱桃谷鸭,随机分成4组,每组6个重复,每个重复10只鸭。对照组樱桃谷鸭饲喂基础日粮,试验组（A500、A800和A1000）在基础日粮中添加500、800、1000mg/kg刺五加多糖,试验为期42d。结果显示,与对照组相比,A800组和A1000组樱桃谷鸭平均日增重（ADG）分别提高14.13%和13.90%(P <0.05),试验各组樱桃谷鸭料重比（F/G）均显著降低（P <0.05）;与对照组相比,A800组和A1000组樱桃谷鸭胸腺指数分别显著提高14.07%和13.59%(P <0.05),法氏囊指数分别显著提高17.05%和15.5%(P <0.05),与对照组相比,A800组和A1000组樱桃谷鸭血清免疫球蛋白A(IgA)分别显著提高16.67%和13.33%(P <0.05),血清白细胞介素-2(IL-2)含量分别显著提高24.74%和17.18%(P <0.05)。综上所述,樱桃谷鸭日粮中添加刺五加多糖能提高樱桃谷鸭的生产性能和机体免疫能力...     

微生态制剂对樱桃谷肉鸭生长性能、屠宰性能及免疫器官发育的影响

本试验旨在研究饲粮中添加不同微生态制剂对樱桃谷肉鸭生长性能、屠宰性能及免疫器官发育的影响.选取320羽10日龄樱桃谷肉鸭,随机分为4组,1个对照组和3个试验组,每组4个重复,每个重复20羽.对照组饲喂基础饲粮,3个试验组分别饲喂在基础饲粮的基础上添加50 mg/kg芽孢杆菌混合物(试验Ⅰ组)、1000mg/kg芽孢杆菌与寡糖混合物(试验Ⅱ组)、1 000 mg/kg芽孢杆菌与链球菌混合物(试验Ⅲ组)的试验饲粮.试验期33 d.结果表明:试验Ⅱ组和试验Ⅲ组的平均日增重显著或极显著高于对照组(P＜0.05或P＜0.01).试验Ⅲ组的平均日采食量、料重比显著低于试验Ⅰ组和对照组(P＜0.05).各试验组的存活率显著或极显著高于对照组(P ＜0.05或P＜0.01).与对照组相比,试验Ⅲ组的腹脂率显著下降(P＜0.05),法氏囊指数显著升高(P＜0.05).由此得出,饲粮中添加芽孢杆菌与寡糖混合物和芽孢杆菌与链球菌混合物均能提高樱桃谷肉鸭的生长性能;此外,饲粮中添加芽孢杆菌与链球菌混合物还可提高樱桃谷肉鸭的胴体品质和免疫机能.     

大豆异黄酮对肉鸡生产性能和胴体品质的影响

试验选用100只21日龄AA肉鸡,随机分为4组,即对照组和3个试验组,每个组设5个重复。对照组饲喂基础日粮,试验组在基础日粮中分别添加3、6、9mg/kg的有效大豆异黄酮。试验结果表明,肉鸡日粮中添加大豆异黄酮对肉鸡生产性能影响差异不显著(P>0.05);31日龄试验组血清中尿酸含量平均比对照组低29.25%(P<0.05);42日龄试验组腹脂垫重/体重比对照组平均低9.50%(P<0.05)。     

葛根素对21日龄樱桃谷鸭钙磷代谢的影响

在此探讨葛根素对21日龄樱桃谷鸭钙、磷代谢的影响。选用健康的1日龄的樱桃谷鸭128只,在基础日粮预饲1周后随机分为4组,每组4个重复,每个重复8只（公母各半）,分别给于添加0mg／kg、5mg／kg、10mg／kg、15mg／kg葛根素的日粮,于21日龄屠宰对血清及骨骼里的钙、磷及相关指标进行检测。结果表明：在21日龄时,血清钙、磷含量的变化并没有明显的规律性,但总体的趋势是,添加葛根素对此时期的骨形成有利,均显著的增加了骨形成指标碱性磷酸酶的含量,同时也伴随了血清钙含量的显著下降（P〈0．05）,而且,葛根素（5mg／kg）剂量添加组对骨形成的效果更好;在21日龄时,葛根素对樱桃谷鸭骨骼各指标的影响与对照组相比差异不显著（P〉0.05）,但葛根素（5mg／kg）剂量添加组使樱桃谷母鸭的股骨湿重、长度、矿物质和钙含量分别提高了6．68％、3.38％、0.62％和22．26％,同时使公鸭的股骨湿重提高了4.52％;使母鸭胫骨的湿重、长度和钙含量分别提高了8．63％、2.88％和23．11％,并且使骨骼钙磷比例最接近于2：1。由此表明,葛根素对樱桃谷鸭的骨骼钙、磷代谢有影响,小剂量的葛根素（5mg／kg）对骨的形成有利,可以有效阻止骨的吸收,促进骨的形成;大剂量的葛根素对骨的形成不利,其主要作用机理是雌激素样作用。     

大豆异黄酮对坝上长尾鸡卵巢功能、生殖激素和肌肉品质的影响

本试验旨在研究大豆异黄酮对坝上长尾鸡卵巢功能、生殖激素和肌肉品质的影响。试验采用单因子试验设计,选取150只坝上长尾鸡(公母各半),随机分为5组,每组3个重复,每个重复10只鸡。Ⅰ~Ⅴ试验组分别在基础日粮中添加5,10,15,20,25 mg/kg剂量的大豆异黄酮。结果显示,卵巢功能各指标在数值上会随着大豆异黄酮添加量的升高表现出先上升后下降的过程。LH:Ⅲ组最高,与Ⅰ组、Ⅴ组差异显著(P<0.05),与Ⅱ组、Ⅳ组差异不显著(P>0.05);FSH:Ⅲ组与高剂量组差异不显著(P>0.05),与低剂量差异显著(P<0.05);E2:Ⅲ组最高,与Ⅰ组差异显著(P<0.05),比Ⅰ组高3.19%;PRL:Ⅲ组最高,与高剂量组和低剂量组差异都不显著(P>0.05);P4:Ⅲ组最高,与Ⅳ组差异不显著(P>0.05)。红度a*:Ⅲ组比Ⅰ组和Ⅴ组显著提高11.12%和9.08%(P<0.05);肌肉pH:Ⅲ组显著低于Ⅰ组和Ⅴ组,分别降低3.81%和2.14%(P<0.05);肌肉系水力:Ⅲ组显著高于Ⅰ组11.9%(P<0.05);剪切力:Ⅲ组显著低于其他剂量组(P<0.05);组织学性状:肌纤维密度Ⅱ组与Ⅲ组显著高于Ⅰ组、Ⅳ组和Ⅴ组(P<0.05),Ⅲ组比Ⅳ组、Ⅴ组分别提高29.20%和36.23%;肌肉风味方面,各试验组间氨基酸差异不显著(P>0.05)。结果表明,适宜的大豆异黄酮(15 mg/kg)能较好地提高坝上长尾鸡卵巢功能、生殖激素水平和肌肉品质。     

大豆异黄酮在畜禽养殖中的应用及研究

大豆异黄酮是大豆中富含的一类黄酮类化合物。由于其具有较弱的雌激素活性．大豆异黄酮在治疗和预防与雌激素有关的疾病方面具有重要的功效。大豆异黄酮还具有促进畜禽日增重、提高饲料利用率和生产性能以及促进畜禽免疫机能等生理功能。介绍了大豆异黄酮的性质、作用机理、在畜禽养殖中的应用及在医学中的功效。     

大豆异黄酮在畜禽生产中的应用及安全性研究进展

大豆异黄酮是来源于豆科植物且具有微弱的雌激素样作用的多酚类混合物,主要活性成分为染料木素、大豆黄酮和黄豆黄素。因其具有提高畜禽生产性能、免疫机能、抗氧化、促进骨代谢等生理作用,越来越多地应用在畜牧生产中。但近年来也出现了一些关于大豆异黄酮安全性和副作用的报道,因此,如何科学有效地利用需要进一步深入研究。文章综述了大豆异黄酮的种类、养分代谢特点、生理特性、对畜禽生产中的促进作用及对动物和人类存在的安全性问题。     

Research Progress on Application and Safety of Soybean Isoflavone in Animal Husbandry

Soybean isoflavone is a kind of faint estrogen-like mixture of polyphenols which derived from the leguminous plants.Its active components include genistein,daidzein and glycitein.It is used in animal husbandry for its physiological functions that it can enhances performance,immune function,antioxidant and improves bone metabolism.But some following reports about safety and side effects of soybean isoflavones are also appeared.That is a worthy further research topic how to use it effectively.The article summarizes the types of soybean isoflavones,nutrient metabolism characteristics,physiological characteristics,the promoting effect of livestock and poultry production and security problems about animal and human.     

Effects of dietary soy isoflavones on growth, carcass traits, and meat quality in growing-finishing pigs

Two experiments were conducted to determine the effect of soy isoflavones on growth, meat quality, and carcass traits of growing-finishing pigs. In Exp. 1, 36 barrows (initial and final BW, 26 and 113 kg, respectively) were used and each treatment was replicated four times with three pigs each. The dietary treatments were 1) corn-soybean meal (C-SBM), 2) corn-soy protein concentrate (low isoflavones, C-SPC), or 3) C-SPC + isoflavones (isoflavone levels equal to those in C-SBM). Daily gain and ADFI were increased (P < 0.10) in pigs fed the C-SPC relative to pigs fed the C-SPC + isoflavone diet in the late finishing period; otherwise, growth performance was not affected (P > 0.10) by diet. Longissimus muscle area, 10th-rib fat depth, percentage muscling (National Pork Producers Council), 24-h pH and temperature, color, firmness-wetness, marbling, drip loss, and CIE L*, a*, and b* color values were not affected (P > 0.10) by diet. Dressing percentage, carcass length, weight and percentage of fat-free lean in ham and carcass, lean gain per day, lean:fat, and ham weight were increased (P < 0.10), and ham fat and percentage fat in ham and carcass were decreased (P < 0.10) in pigs fed the C-SPC + isoflavone diet compared with pigs fed the C-SPC diet. Pigs fed the C-SPC + isoflavone diet had similar (P > 0.10) carcass traits as pigs fed the C-SBM diet, except carcass length, percentage ham lean and thaw loss were greater (P < 0.10), and total ham fat was less (P < 0.10) in pigs fed the C-SPC + isoflavone diet. In Exp. 2, 60 gilts (initial and final BW, 31 and 116 kg, respectively) were used, and each treatment was replicated five times with four pigs per replicate. The treatments were 1) C-SBM, 2) C-SBM + isoflavone levels two times those in C-SBM, and 3) C-SBM + isoflavone levels five times those in C-SBM. Daily feed intake was linearly decreased (P < 0.10) in the growing phase and increased (P < 0.10) in the late finishing phases as isoflavone levels increased; otherwise, growth performance was not affected (P > 0.10) by diet. Diet did not affect (P > 0.10) carcass traits; however, CIE a* and b* color scores and drip loss were decreased (P < 0.06) as isoflavone levels increased. Soy isoflavones decreased fat and increased lean in barrows when fed within the dietary concentrations found in typical C-SBM diets but not when fed to gilts at concentrations above those present in C-SBM diets.     

Exposure of growing and adult captive cheetahs (Acinonyx jubatus) to dietary isoflavones: twenty years later

Dietary isoflavones are associated with oestrogenic and anti‐oestrogenic effects, and have been linked to infertility in cheetahs. This study aimed to determine the isoflavone content of commercially prepared diets consumed by captive cheetahs. Sixteen international zoological facilities provided diets, and the isoflavone content of each diet was determined by acid hydrolysis and HPLC quantification. Proximate nutritional composition was also determined. Over half the diets analysed contained detectable concentrations of isoflavones, whereby total isoflavone content ranged from 1.75–183 mg/kg dry matter. The zoo‐specific diets were calculated to deliver a median isoflavone dose of 0.07 mg/kg body weight (BW) and a maximum of 1.95 mg/kg BW to captive cheetahs. On a metabolic body weight basis this equates to a maximum of 4.90–5.43 mg/kg^0.75. Some diets prepared for hand‐rearing neonatal cheetahs could expose neonates to doses of up to 4.24 mg/kg BW (or 4.24–6.33 mg/kg^0.75 for cubs under 3 months of age). Only one of six zoo‐specific diets was found to deliver isoflavones in doses shown to possess biological activity in other species. Therefore, on average, dietary isoflavones were not found in commercially prepared diets consumed by captive cheetahs in concentrations predicted to cause physiological changes. However, a small proportion of these diets, including hand‐rearing formulas, contained elevated isoflavones concentrations which may influence cheetah fertility, behaviour or other physiological parameters.     

大豆异黄酮对蛋鸡小肠肠道黏膜结构的影响

选取200只1日龄健康的蛋鸡,随机平均分为2组：试验组（T组）日粮中添加大豆异黄酮提取物20mg/kg,对照组（C组）饲喂基础日粮,分别于10、15、22、29、37日龄取材,制作石蜡切片及HE染色,显微成像系统测定十二指肠、空肠和回肠的绒毛长度、隐窝深度和肌层厚度。结果显示,随着日龄（15~37日龄）的增长,T组蛋鸡十二指肠、空肠和回肠的肌层厚度和V/C值都有低于C组蛋鸡的趋势。结果说明,20mg/kg的大豆异黄酮提取物的添加量对蛋鸡的小肠肠道黏膜结构有负面影响,不利于蛋鸡的生长。     

Nutritional and pathophysiologic effects of clinically apparent and subclinical infections of Ostertagia ostertagi in calves.

Nutritional and physiologic effects of clinically apparent and subclinical Ostertagia ostertagi infections were studied in 3 groups of 5 calves each. Group-1 calves were inoculated with 100,000 Ostertagia ostertagi third-stage larvae (L3)/calf/wk for 14 weeks. Group-2 calves were inoculated with 10,000 L3/calf/wk for 14 weeks, and group-3 calves were no inoculated. Calves in group 1 had decreased dry matter intake and feed utilization from 4 weeks after initial inoculation. Group-2 calves had no changes in dry matter intake, but had decreased feed utilization at 12 and 14 weeks. Calves with clinically apparent infections (group 1) lost a mean weight of 11.8 kg, whereas calves with suclinical infections (group 2) lost a mean of 46.6 kg, and control calves lost a mean of 60.7 kg. Calves with O ostertagi infections (group 1 and 2) also had decreased carcass quality at slaughtering, which was reflected in decreased dressing weights and increased water-holding capacity of the rib-eye muscle. Calves in groups 1 and 2 also had lower carcass yield and rib-eye muscle weight, and group-1 calves had decreased protein content. Results of hematologic, pathologic, parasitologic, and clinical examinations mirrored nutritional changes.     

Identification and concentration of soy isoflavones in commercial cat foods

OBJECTIVE: To determine the absolute and relative soy isoflavone content in commercial cat foods. SAMPLE POPULATION: 14 dry, 6 semimoist, and 22 moist commercial cat foods. PROCEDURE: Soy isoflavone content of each food was determined by use of acid-methanol hydrolysis and high-pressure liquid chromatography with ultraviolet absorbance detection. Isoflavones were identified and quantified by reference to authentic standards. RESULTS: Genistein and daidzein were the major soy isoflavones identified in 24 of 42 foods, with concentrations ranging from 1 to 163 microg/g of food. Foods labeled as containing soybean solids (16/42) had isoflavone concentrations > 11 microg/g. More dry (13/14) and semimoist (6/6) foods contained isoflavones than moist foods (5/22). Isoflavone content and food cost were negatively correlated for dry and semimoist foods but not for moist foods. Total amount of isoflavone consumed by cats fed these soy-containing foods as a sole maintenance diet was estimated to be between 0.6 and 4.5 mg/kg of body weight/d, which is comparable to concentrations in humans that result in a measurable although modest effect on serum concentrations of steroid and thyroid hormones. CONCLUSIONS AND CLINICAL RELEVANCE: Genistein and daidzein are common constituents of commercial cat foods. Predictors of isoflavone content included ingredient labeling, food type, and food cost. Soy isoflavones in some commercial cat foods were detected in amounts predicted to have a biological effect.     

Dietary thyroid hormone improves growth and muscle protein accumulation of black-boned chickens

1. The objective of the study was to examine the effect of dietary thyroid hormone on performance and muscle protein accumulation of black-boned chickens. 2. A total of 720 1-d-old birds was housed in 24 pens and assigned to 4 diets containing triiodothyronine (T3) at 0, 0.1, 0.3 or 0.5 mg/kg. 3. The trial was split into starter (0 to 4 weeks) and grower (5 to 8 weeks) phases. At the beginning of the grower phase, each pen was split into two; one subgroup was fed basal diet (T3-) and the other continued with T3-added diet (T3+). 4. Dietary T3 at 0.1 mg/kg improved average daily body weight gain until week 6 but retarded it thereafter. However, T3 at 0.5 mg/kg depressed growth throughout the whole period. During weeks 7 to 8, T3 retarded growth, whereas growth recovered when T3 was withdrawn from the diet. 5. Birds fed the diet containing 0.1 mg/kg during weeks 0 to 4 and those receiving basal diet during weeks 5 to 8 showed the greatest thigh muscle growth, but this growth was depressed when they were fed the 0.5 mg/kg diet during weeks 0 to 8. 6. Serum T3 concentration was increased, while thyroxine (T4) concentration was decreased by dietary T3 treatment at 2 weeks old. At 4 weeks old, T3 and T4 concentrations decreased. At 6 and 8 weeks old, among T3-treated groups the serum T3 concentration of the T3- group was higher than that of the T3+ group. 7. In conclusion, dietary T3 improved weight gain and muscle growth of black-boned chickens before week 6, whereas supplementation depressed growth after 6 weeks. Optimum dietary T3 concentrations showed a carry-over effect on both body weight gain and thigh muscle growth.