杜洛克母猪生长，肥育阶段补充维生素E和维生素C的效果

在生长猪日粮（含添加剂VE7IU／kg）中添加VE50IU／kg和VC100mg/kg，对杜洛克生长母猪的生产性能无明显影响，肥育猪日粮（含添加剂ＶＥ４.9ＩＵ/kg）中添加ＶＥ２５IU/kg和ＶＣ５０mg/kg，可提高日增重８.６％，单位增重的饲料消耗下降11.7％。表明杜洛克母猪肥育日粮的ＶＥ和ＶＣ水平可能应高于生长阶段。     

维生素E和维生素C对热应激时肉仔鸡某些血液生化指标的影响

主要研究日粮中不同水平的VE、VC对肉仔鸡某些血液生化指标的影响.结果表明在日粮中添加50 mg/kg VE、200 mg/kg VC或200mg/kg VE、50 mg/kg VC可显著提高热应激时肉仔鸡血清中γ-球蛋白值;在日粮中添加50 mg/kg VE、50 mg/kg VC对提高乳酸脱氢酶、碱性磷酸酶活性效果较好;热应激时添加VE、VC对肉仔鸡谷丙转氨酶活性的影响有待探讨.     

维生素E和维生素C对热应激时肉仔鸡某些血液生化指标的影响

主要研究日粮中不同水平的VE、VC对肉仔鸡某些血液生化指标的影响。结果表明：在日粮中添加50mg/kg VE、200mg/kg VC或200mg/kg VE、50mg/kg VC可显著提高热应激时肉仔鸡血清中γ－球蛋白值；在日粮中添加50mg/kg VE、50mg/kg VC对提高乳酸脱氢酶、碱性磷酸酶活性效果较好；热应激时添加VE、VC对肉仔鸡谷丙转氨酶活性的影响有待探讨。     

维生素C、E及其交互作用对肉仔鸡生长性能及鸡肉品质的影响

本试验旨在研究维生素C、E(VC、VE)及其交互作用对肉仔鸡生长及其鸡肉品质的影响。试验采用4×4完全随机试验设计将800只1日龄健康的艾维茵肉仔鸡随机分成16个处理,每个处理5个重复,每个重复10只。其中,VE设4个添加水平,分别为50、100、200、400 mg/kg日粮,VC的添加水平为50、100、200、400 mg/kg日粮。结果表明:在生长前期(0～21 d),日粮VE、VC的添加量对肉仔鸡日增重均无显著影响(P>0.05),VE、VC的互作效应在生长前期对肉仔鸡日增重和料重比的影响均不显著(P>0.05),前期VE(200 mg/kg)×VC(50 mg/kg)组料重比最低;在生长后期(4～6周龄),日粮VE、VC的添加量对肉仔鸡日增重、料重比的影响均显著(P<0.05),VE、VC的互作效应对肉仔鸡生长后期日增重和料重比的影响均显著(P<0.05);不同的VE、VC处理组之间pH 45 min、pH 12h、pH 24 h值、肉色、肌间脂肪、最大剪切力的差异均不显著(P>0.05),且VE、VC之间无显著的互作效应(P>0.05);不同维生素E组之间的滴水损失率差异极显著(P<0.01),...     

高温期维生素E和C对肥育猪生长与代谢的影响

将来源相同、体重相近 (55kg) 的杜长大生长肥育猪 36头 ,公母各半 ,随机分为 3个处理 ,每个处理设 3个重复 (各组间差异不显著 ) ,每个重复公母各 2头 ,在试验日粮中分别添加维生素C(50mg·kg- 1 )和维生素E(2 0 0mg·kg- 1 ) ,研究日粮维生素对持续高温期生长肥育猪生长性能与生化指标的影响。研究结果表明维生素E和C对持续高温期生长肥育猪的生长性能、内分泌功能、血清生化指标、血清电解质平衡等方面都会产生明显的影响。与对照组相比 ,生长肥育猪在热应激期采食维生素日粮后出现 :(1 )VC组平均日增重显著增加 (p <0 0 5) ;VC组和VE组间平均日增重差异不显著 (p >0 0 5) ;(2 )血清游离甲状腺素T4 显著增高 (p <0 0 5) ,游离T3也呈增高趋势 (p >0 0 5) ,VC组和VE组间血清T3、T4 浓度差异不显著 (p >0 0 5) ;(3)维生素组血清TP、ALB浓度显著增高 (p <0 0 5) ,血清BUN浓度显著降低 (p <0 0 5) ,而血清GLU、CHO、TG、GLO变化不显著 (p >0 0 5) ;(4)维生素组血清K+ 浓度显著增高 (p <0 0 5) ,Cl- 水平略有降低 ,Ca+ + 水平呈现出增加趋势 ,但变化都不显著 (p >0 0 5)。     

γ氨基丁酸对高温环境下生长肥育猪生产性能及激素水平的影响

将96头45 kg左右的杜长大三元杂交商品猪分成4组,日粮中分别添加0(对照)、10、30及50 mg/kg的γ氨基丁酸(GABA),在45 d的试验期内,研究高温环境下日粮添加GABA对生长肥育猪生产性能及抗应激效果的影响.结果表明:日粮添加10、30及50 mg/kg GABA显著提高猪采食量、日增重(P<0.05).血清HPA、HPT激素检测结果表明,GABA降低猪血清ACTH含量(P<0.01),且30、50 mg/kg处理组显著低于10 mg/kg组.与对照组相比,日粮添加30 mg/kg GABA显著降低猪血清COR浓度(P<0.01),而10、50 mg/kg效果不显著(P>0.05).10、30及50 mg/kg GABA均显著降猪低血清CORS含量(P<0.01).日粮添加30或50 mg/kg GABA显著提高猪血清T3、T4含量(P<0.01).实验结果显示,日粮添加GABA可以缓解高温环境生长肥育猪的热应激,提高生产性能.     

半胱胺对肥育猪生产性能和胴体的影响

选择体重60kg左右的杜长大杂交猪144头，随机分成4组，分别在基础日粮中添加半胱胺0、100、150和350mg/kg。试验结果：日粮中添加100、150mg/kg半胱胺使试验猪体重增加5．6％和12．7％，而添加350mg/kg半胱胺却使增重降低了11．4％；与对照组相比，添加100、150和350mg/kg半胱胺耗料增重比分别降低了6．5％、12．1％和－10．2％；添加100、150mg/kg半胱胺使每头猪增加收入5．35元和12．61元，而添加350mg/kg时，减少收入30．89元；试验结果表明，在肥育猪日粮中添加100和150mg/kg半胱胺能明显提高猪的生产性能，而添加过量的半胱胺却反而降低了猪的生产性能。     

三氧化砷促进肥育猪生长的研究

在日粮中分别添加不同剂量的三氧化砷（0.6,1.0,1.4,1.8mg/kg)和40mg／kg的洛克沙生饲喂肥育猪，研究了三氧化二砷和洛克沙生对肥育猪生长的影响及三氧化二砷在肥育猪日粮中的适宜剂量。试验结果表明：三氧化二砷促进肥育猪生长的适宜剂量为0.6mg/kg,它和40mg/kg的洛克沙生一样，具有显著的促生长效果。     

维生素E和氯化汞对比目鱼生长性能和汞生物学蓄积的交互作用

本研究进行6周的饲养试验,评估维生素E(VE)和汞对比目鱼生长性能和汞生物学蓄积的影响。试验采用2×3因子设计,将360条比目鱼随机分到6组,每组3个重复,每个重复20条鱼。对照组饲喂基础日粮,处理组分别在基础日粮中添加100、200 mg/kg VE、15 mg/kg汞、15 mg/kg汞+100 mg/kg VE、15 mg/kg汞+200 mg/kg VE。结果显示,日粮添加汞显著抑制比目鱼的增重、特定生长率、饲料效率和蛋白效率(P<0.05),而VE显著改善增重(P<0.05)。汞和VE对试验期间比目鱼的存活率无显著影响(P>0.05)。日粮补充VE对比目鱼粗脂肪、水分有一定影响。VE显著降低肌肉、肝脏和肾脏汞含量(P<0.05),但日粮添加汞降低了组织VE含量(P<0.05)。汞显著降低了比目鱼机体二十碳五烯酸和二十二碳六烯酸含量(P<0.05),补充VE后显著改善了机体亚麻酸和二十碳五烯酸含量(P<0.05)。结果表明,日粮中添加VE对比目鱼生长发育具有促进作用,同时有降低无机汞在机体蓄积的潜在作用。     

有机硒和维生素E对母猪生产性能的影响

试验采用随机区组设计,2×2因子设计,在相同的日粮基础上,妊娠期和哺乳期分别添加0.3 mg/kg亚硒酸钠(以硒计)+22 IU/kg VE0、.3 mg/kg酵母硒(以硒计)+22 IU/kgVE0、.3 mg/kg亚硒酸钠(以硒计)+44 IU/kg VE、0.3 mg/kg酵母硒(以硒计)+44 IU/kg VE的日粮。结果表明:妊娠1 d、妊娠60 d、哺乳3 d、哺乳14 d,0.3 mg/kg酵母硒(以硒计)+44 IU/kg VE的日粮获得母猪血清中硒的最高含量。妊娠1 d、妊娠60 d、哺乳3 d、哺乳14 d,各处理母猪血清中抗氧化指标GSH-PX差异不显著。哺乳3 d、哺乳14 d各阶段均反映出0.3 mg/kg酵母硒(以硒计)+44 IU/kg VE的日粮获得乳猪血清中硒的最高含量。不同处理对不同阶段乳猪血清中GSH-PX的含量,哺乳第3 d各处理差异不显著;哺乳14 d添加0.3 mg/kg亚硒酸钠(以硒计)+22 IU/kg VE的处理和0.3 mg/kg酵母硒(以硒计)+44 IU/kg VE处理差异显著(P0.05)。     

玉米脱水酒精糟及其可溶物和维生素 Ｅ水平对肥育猪生长性能、胴体和肉品质的影响

本试验旨在研究饲粮中玉米脱水酒精糟及其可溶物（ＤＤＧＳ）和维生素 Ｅ（ＶＥ）水平对肥育猪生长性能、胴体和肉品质的影响。采用 ３×２两因子完全随机试验设计,设 ３个玉米ＤＤＧＳ水平（０、１５％、３０％）和 ２个维生素 Ｅ水平（１０、２１０ｍｇ／ｋｇ）。选取平均体重为（６０±２）ｋｇ的“杜 ×长 ×大”三元杂交肥育猪 ４８头（公母各占 １／２）,按性别、体重随机分为 ６个组,每个组 ８个重复,每个重复 １头猪。试验期为 ４２ｄ。结果表明：１）玉米 ＤＤＧＳ水平对肥育猪平均日增重和料重比无显著影响（Ｐ＞０．０５）,对平均日采食量影响极显著（Ｐ＝０．００６）,维生素 Ｅ水平及玉米 ＤＤＧＳ和维生素 Ｅ的互作对生长性能无显著影响（Ｐ＞０．０５）;２）玉米 ＤＤＧＳ和维生素Ｅ水平及其互作对胴体重、屠宰率、胴体斜长、背膘厚度、板油率和眼肌面积等胴体品质评定指标影响均不显著（Ｐ＞０．０５）,胴体脂肪碘值随饲粮中玉米 ＤＤＧＳ水平的提高而极显著升高（Ｐ＝０．００１）;３）玉米 ＤＤＧＳ水平对肌肉 ｐＨ、肉色、剪切力、滴水损失和大理石评分影响均不显著（Ｐ＞０．０５）,饲粮中添加 ２１０ｍｇ／ｋｇ维生素 Ｅ可显著降低肌肉剪切力和滴水损失（Ｐ＜０．０５）。可见,在肥育猪基础饲粮中添加 １５％ ～３０％玉米 ＤＤＧＳ和 ２１０ｍｇ／ｋｇ维生素 Ｅ对其生长性能、胴体和肉品质无显著负影响。     

中华鲟幼鲟维生素C营养需要的研究

本研究旨在确定中华鲟幼鲟对维生素C(VC)的营养需要量。配制含VC分别为0.5、59.8、119.5、239.1、478.1和956.2 mg/kg饲料的6组日粮(分别编号为C0.5、C59.8、C119.5、C239.1、C478.1和C956.2),连续投喂中华鲟幼鲟8周后,以生长速度、组织VC含量和部分相关酶活性来确定中华鲟对VC的需求量。结果表明,C0.5和C59.8组鲟鱼的增重率、饲料效率、蛋白质效率都低于C119.5组,进一步提高饲料VC含量,也没有显著变化(P>0.05);C478.1组的肝脏和肌肉组织VC含量达最高水平;C239.1组血清溶菌酶活性最高;C239.1组SOD活性最低。根据平均增重率和饲料效率做折线法分析表明,维持中华鲟最佳生长的饲料VC含量为108.5 mg/kg;肝脏中VC含量达最大时饲料VC添加量为309.4 mg/kg;肌肉中VC含量达最大时饲料VC添加量为273.3 mg/kg。     

Response of growing-finishing pigs to decreasing floor space allowance and(or) virginiamycin in diet

Five hundred forty crossbred pigs were utilized in four trials (10 replications) at two stations to determine the separate and interacting effects of decreasing floor space allowance with or without the addition of virginiamycin to the diet on performance of growing-finishing pigs. Pigs were allowed .37, .33 or .28 m2/pig during the growing phase (23 to 55 kg) and .74, .66, .56 m2/pig during the finishing phase (55 to 100 kg) and fed either a corn-soybean meal control diet or the control diet plus 11 mg of virginiamycin/kg of diet. Floor space allowances were achieved by varying pen size, so the number of pigs and feeder space per pig were constant for all pens. During the growing phase, daily gain (P less than .01) daily feed intake (P less than .05) and feed conversion ratio (P less than .05) decreased as floor space allowance decreased. During the finishing phase and for the total test period, daily gain (P less than .01) and feed conversion ratio (P less than .05) were reduced but daily feed intake was not affected (P greater than .05) by restricted floor space allowance. The addition of virginiamycin to the diet had no effect on pig performance. The virginiamycin X floor space allowance interaction was not significant, suggesting that pigs fed a diet with or without virginiamycin responded similarly to restricted floor space allowance. The data suggest that the addition of virginiamycin to the diet was ineffective in overcoming the decrease in performance of growing-finishing pigs caused by crowded conditions.     

姜黄素替代育肥猪饲粮中喹烯酮对抗体合成和猪肉品质的影响

试验研究了姜黄素替代猪饲粮中抗菌药物喹烯酮对抗体的合成和猪肉品质的影响。选取64头体重约70 kg的杜×长×大三元杂交猪,将其分为4组,每组16头猪。在基础饲粮中添加50 mg/kg喹烯酮后,饲喂第1组(对照组)猪;在基础饲粮中分别添加200、3004、00 mg/kg姜黄素后,相应地饲喂第23、4、组猪,饲养试验期40 d。试验结果表明:姜黄素替代育肥猪饲粮中喹烯酮,对猪体健康无不良影响;能改善猪的肉品质量;不同程度地提高猪的病原抗体效价。育肥猪饲粮中姜黄素的适宜添加量为400 mg/kg。     

Vitamin E requirement of growing swine

The vitamin E requirement of growing pigs was estimated on the basis of prevention of morphological signs of deficiency. Five groups of pigs were fed a barley-based diet low in vitamin E that contained 16 mg of DL-alpha-tocopheryl acetate equivalents/kg and .1 ppm of Se for 4 wk (depletion I). This period was followed by 7 wk of supplementation, during which the groups received 0, 15, 45, 135 and 405 mg of supplemental DL-alpha-tocopheryl acetate/kg diet. Finally, all the animals were fed the low vitamin E diet for 7 wk (depletion II). To follow the vitamin E concentration in serum and tissues, blood samples were collected and biopsies were taken from skeletal muscle, adipose tissue and the liver throughout the experiment. The peak vitamin E value was observed in the liver, followed by the adipose tissue and then skeletal muscle. The liver responded rapidly to changes in dietary vitamin E intake, whereas the adipose tissue and the skeletal muscle reacted at a slower rate. In spite of the abundant occurrence of the different vitamin E isomers in the feed, alpha-tocopherol was the main isomer detected both in the serum and in the tissues. The activity of glutathione peroxidase in serum increased with age but was independent of the serum vitamin E concentration. In the unsupplemented group all animals suffered from the vitamin E and Se deficiency syndrome (VESD) in an acute or chronic form. A total of 31 mg of DL-alpha-tocopheryl acetate/kg diet (16 mg of naturally occurring vitamin E and 15 mg as supplementation) equivalent to 2.5 IU vitamin E/g polyunsaturated fatty acids (PUFA) was enough to prevent the development of VESD. In view of the large individual variations of vitamin E concentration in target organs, and to obtain a certain safety margin for prevention of VESD in growing pigs, a supplement of 30 mg of DL-alpha-tocopheryl acetate/kg diet is recommended.     

Growing-finishing performance and carcass characteristics of pigs fed normal and genetically modified low-phytate corn

A genetically modified corn hybrid homozygous for the lpa1 allele, containing low phytate (LP), and its nearly isogenic equivalent hybrid (normal) were compared in two experiments with growing-finishing swine. In Exp. 1, 210 barrows (27 kg) were allotted to one of six dietary treatments with two corn hybrids (LP and normal) and three P feeding regimens. There were five replicate pens (seven pigs/pen) per treatment. Treatments consisted of diets that were supplemented with P throughout the growing-finishing period (.2% P and .15% supplemental P during growing and finishing phases, respectively) or only during the growing phase (.2% supplemental P) or that were not supplemented with P throughout the growing-finishing period. Performance at the end of the growing phase was based on a 2 x 2 factorial arrangement of treatments with two corn hybrids and two levels of added P (0 and .2%). This resulted in 10 replicates for the treatments supplemented with .2% P. The finishing phase (73 to 112 kg) was a 2 x 3 factorial arrangement of treatments with the two types of corn and three regimens of added P during the finishing period. Breaking load (BL) and ash of the fourth metacarpal were evaluated from one pig/pen at the end of the growing phase and from all pigs after slaughter. Pigs fed the LP corn diet without added P had greater body weight gain, feed efficiency, BL, and ash content of the fourth metacarpal than pigs fed the normal corn diet without added P. Performance was similar between pigs fed the LP diet without added P and pigs fed LP and normal corn with added P. In Exp. 2, 1,092 gilts (34 kg body weight) were allotted by weight in a commercial facility to one of three treatments: 1) normal corn/soybean meal diet containing .29% and .22% available P during the growing and finishing phases, respectively; 2) LP corn/soybean meal diet with the same available P level as Treatment 1; and 3) same as Treatment 2 for 8 wk, then no inorganic P supplementation during the finishing phase. All pigs were slaughtered at approximately 122 kg. There were no significant differences in growing-finishing performance or BL among treatments. However, pigs fed diets containing LP corn possessed carcasses with less backfat and a higher percentage of lean (P < .01). These results confirm that the P in LP corn is available to the pig and suggest that pigs fed diets containing this genetically modified corn will have more desirable carcasses.     

Effects of dietary iron level on growth performance,hematological status,and intestinal function in growing-finishing pigs

This study investigated the different addition levels of iron (Fe) in growing-finishing pigs and the effect of different Fe levels on growth performance, hematological status, intestinal barrier function, and intestinal digestion. A total of 1,200 barrows and gilts ([Large White × Landrace] × Duroc) with average initial body weight (BW; 27.74 ± 0.28 kg) were housed in 40 pens of 30 pigs per pen (gilts and barrows in half), blocked by BW and gender, and fed five experimental diets (eight replicate pens per diet). The five experimental diets were control diet (basal diet with no FeSO₄ supplementation), and the basal diet being supplemented with 150, 300, 450, or 600 mg/kg Fe as FeSO₄ diets. The trial lasted for 100 d and was divided into the growing phase (27 to 60 kg of BW) for the first 50 d and the finishing phase (61 to 100 kg of BW) for the last 50 d. The basal diet was formulated with an Fe-free trace mineral premix and contained 203.36 mg/kg total dietary Fe in the growing phase and 216.71 mg/kg in the finishing phase based on ingredient contributions. And at the end of the experiment, eight pigs (four barrows and four gilts) were randomly selected from each treatment (selected one pig per pen) for digesta, blood, and intestinal samples collection. The results showed that the average daily feed intake (P = 0.025), average daily gain (P = 0.020), and BW (P = 0.019) increased linearly in the finishing phase of pigs fed with the diets containing Fe. On the other hand, supplementation with different Fe levels in the diet significantly increased serum iron and transferrin saturation concentrations (P < 0.05), goblet cell numbers of duodenal villous (P < 0.001), and MUC4 mRNA expression (P < 0.05). The apparent ileal digestibility (AID) of amino acids (AA) for pigs in the 450 and 600 mg/kg Fe groups was greater (P < 0.05) than for pigs in the control group. In conclusion, dietary supplementation with 450 to 600 mg/kg Fe improved the growth performance of pigs by changing hematological status and by enhancing intestinal goblet cell differentiation and AID of AA.     

Vitamin A nutrition of growing cockatiel chicks (Nymphicus hollandicus)

The experiments examined the physiological response of growing cockatiel chicks to varying levels of dietary vitamin A (VA) or beta-carotene and the rate of liver VA uptake. Adult cockatiels breeding pairs (n=10 pairs) were fed a VA-deficient diet for approximately 90 days prior to onset of egg laying. Breeding pairs were then allowed to feed their chicks diets containing either 0 IU VA/kg, 4000 IU VA/kg, or 2.4 mg beta-carotene/kg. After 5 weeks, chicks fed 0 IU VA developed poor feathering, facial dermatitis and reduced body weight (p<0.05). Liver VA was higher in chicks fed 4,000 IU VA or 2.4 mg beta-carotene vs. those fed 0 IU VA (p<0.05). Duodenal beta-actin and 15,15'-dioxygenase mRNA expression was similar to that of growing chickens, and greatest for cockatiel chicks fed 0 IU VA (p<0.01). Chicks fed 0 IU VA had keratinization of the bursa and oral mucosa, and reduced bursa development and lymphocyte density (p<0.05). Finally, when chicks fed 0 IU VA were orally gavaged with 20 IU VA/g body weight, maximal liver retinol uptake occurred between 0 and 24 h and reached a plateau at 36 h. These data demonstrate that VA deficiency can be prevented with 4,000 IU VA/kg diet or 2.4 mg beta-carotene/kg diet, although beta-carotene conversion to VA may be lower in cockatiels than chickens.     

Investigation into selenium requirement of growing turkeys offered a diet supplemented with two levels of vitamin E

To evaluate dietary selenium (Se) requirement in turkeys offered a diet supplemented with two levels of vitamin E (VE), 96 newly hatched male BIG 6^® chicks (58.4 ± 4.12 g) were divided into eight groups of 12 animals each and fed maize soya diets containing 0.05, 0.10, 0.20 and 0.30 mg Se/kg from sodium selenate in combination either with the natural VE content (approximately 10 IU/kg) or with a VE addition of 50 IU/kg. Animals from all the groups were highly performant and their final body weights (1746 ± 190 g) after 35 days on experiment were not significantly different. According to its dietary supply, Se concentration in the liver and plasma increased dose dependently. Independent of dietary VE, the activities of GPx3 in plasma and of GPx1 in liver and breast muscle increased to a larger extent in turkeys supplemented with 0.10 and 0.20 mg Se/kg in relation to animals with low marginal Se supply (0.05 mg/kg). Supplementation of 0.30 mg Se/kg only slightly increased further selenoprotein activities. 2‐Thiobarbituric acid reactive substances in the liver were strongly reduced by dietary VE, but not by Se. Plasma aspartate aminotransferase (AST) and creatine kinase (CK) activities did not show muscular lesions in none of the groups. Although there were no signs of muscular lesions even in turkeys with marginal Se and moderate VE supply, the activity of selenoproteins in various organs increased up to 0.30 mg Se/kg diet, independent of VE supply. It was concluded that for growing turkeys the Se supply should meet at least a level of 0.20 mg/kg diet as currently recommended by the National Research Council and Gesellschaft für Ernährungsphysiologie. Vitamin E addition confirmed the particular function of the vitamin as a lipid antioxidant and should be taken into consideration when diets with high PUFA concentrations are fed.     

The nutritional value of normal and high lysine corns for weanling and growing-finishing swine when fed at four lysine levels

One-hundred-ninety-two weanling pigs from two separate trials, (initial weight 6.0 and 5.6 kg) and 400 growing-finishing pigs (initial weight 17 kg) were fed normal and high lysine corn diets containing four levels of lysine in a 2 X 4 factorial arrangement. Crossbred (Large White X Landrace X Duroc) pigs were used in all experiments. The objectives of the experiments were to (1) compare normal and high lysine corn when fed at different lysine levels, (2) determine the lysine requirements for the three stages of growth and (3) evaluate the effect of protein level on the lysine requirement. All diets were balanced on a lysine basis. The results indicated that both weanling and growing-finishing pig performance and final carcass composition were similar for pigs fed normal or high lysine corn diets balanced on a lysine basis. Weanling pigs from 5 to 14 kg required at least 1.10% lysine. Based on changes in body weight gain and feed efficiency, the lysine requirement of growing pigs (17 to 54 kg) was .70%, and that of finishing pigs (54 to 101 kg) was .50%. However, based on lean tissue growth rate (as reflected by longissimus muscle area and percentage of lean in the carcass) the requirement was at least .75% during the growing stage and .60% during the finishing stage. The reduced protein level (2% lower) of the high lysine corn diets did not reduce the lysine required by pigs compared with those fed normal corn.