Effects of dietary energy density and lysine:calorie ratio on growth performance and carcass characteristics of growing-finishing pigs

We conducted two experiments to evaluate the effects of dietary energy density and lysine:calorie ratio on the growth performance and carcass characteristics of growing and finishing pigs. In Exp. 1, 80 crossbred barrows (initially 44.5 kg) were fed a control diet or diets containing 1.5, 3.0, 4.5, or 6.0% choice white grease (CWG). All diets contained 3.2 and 2.47 g of lysine/Mcal ME during growing (44.5 to 73 kg) and finishing (73 to 104 kg), respectively. Increasing energy density did not affect overall ADG; however, ADFI decreased and feed efficiency (Gain:feed ratio; G:F) increased (linear, P < .01). Increasing energy density decreased and then increased (quadratic, P < .06) skinned fat depth and lean percentage. In Exp. 2, 120 crossbred gilts (initially 29.2 kg) were used to determine the effects of increasing levels of CWG and lysine:calorie ratio fed during the growing phase on growth performance and subsequent finishing growth. Pigs were fed increasing energy density (3.31, 3.44, or 3.57 Mcal ME/kg) and lysine:calorie ratio (2.75, 3.10, 3.45, or 3.80 g lysine/Mcal ME). No energy density x lysine:calorie ratio interactions were observed (P > .10). Increasing energy density increased ADG and G:F and decreased ADFI of pigs from 29.5 to 72.6 kg (linear, P < .05). Increasing lysine:calorie ratio increased ADG and ADFI (linear, P < .01 and .07, respectively) but had no effect on G:F. From 72.6 to 90.7 kg, all pigs were fed the same diet containing .90% lysine and 2.72 g lysine/Mcal ME. Pigs previously fed with increasing lysine:calorie ratio had decreased (linear, P < .02) ADG and G:F. Also, pigs previously fed increasing CWG had decreased (linear, P < .03) ADG and ADFI. From 90.7 to 107 kg when all pigs were fed a diet containing .70% lysine and 2.1 g lysine/Mcal ME, growth performance was not affected by previous dietary treatment. Carcass characteristics were not affected by CWG or lysine:calorie ratio fed from 29.5 to 72.6 kg. Increasing the dietary energy density and lysine:calorie ratio improved ADG and G:F of growing pigs; however, pigs fed a low-energy diet or a low lysine:calorie ratio from 29 to 72 kg had compensatory growth from 72 to 90 kg.     

标准回肠可消化色氨酸与赖氨酸比值对保育猪生长性能的影响

本研究的两个试验旨在评估保育猪最佳生长性能所需的标准回肠可消化(SID)色氨酸与赖氨酸的比值。试验配方确保赖氨酸作为第二限制性氨基酸。试验1中(饲养体重阶段为6~10 kg),255头保育仔猪(PIC 327×1050,初始体重为6.3±0.15kg,平均数±标准差)按栏重分为6个处理,每个处理7栏(每栏为1个重复),每栏饲养6至7头仔猪。6个处理的SID赖氨酸水平均为1.30%,但SID色氨酸与赖氨酸比值分别为14.7%、16.5%、18.4%、20.3%、22.1%和24.0%,试验为期14天。试验2中(饲养体重阶段为11~20 kg),1088头保育仔猪(PIC 337×1050,初始体重11.2±1.35 kg,平均数±标准差)按保育猪的平均体重分为7个处理,每个处理6栏(每栏为1个重复),每栏饲养24至27头仔猪。7个处理的配方均含30%玉米干酒糟且SID赖氨酸水平均为0.97%,但SID色氨酸与赖氨酸比值分别为14.5%、16.5%、18.0%、19.5%、21.0%、22.5%和24.5%,试验为期21天。试验结果统计采用含异残差的一般线性混合模型。竞争异方差模型包括折线线性(BLL)、折线二次(BLQ)和二次多项式(QP)模型。试验结果根据贝叶斯信息准则来选择最佳模型。在试验1中(体重6~10 kg阶段的保育仔猪),随着SID色氨酸与赖氨酸比值的提高,保育仔猪平均日增重和饲料转化率也提高(呈线性,P0.05)。在仔猪平均日增重方面,最佳模型是二次多项式,获得最佳日增重的SID色氨酸与赖氨酸比值为23.9%(95%置信区间:[14.7%,24.0%])。在仔猪料重比方面,最佳模型是折线线性,获得最佳料重比的SID色氨酸与赖氨酸比值为20.4%(95%置信区间:[14.3%,26.5%])。在试验2中(体重11~20 kg阶段的保育仔猪),随着SID色氨酸与赖氨酸比值的提高,保育仔猪平均日增重和饲料转化率也提高(呈二次方式,P0.05)。在仔猪平均日增重方面,最佳模型是二次多项式,获得最佳日增重的SID色氨酸与赖氨酸比值为21.2%(95%置信区间:[20.5%,21.9%])。在仔猪料重比方面,折线线性和二次折线模型都比较适合,获得最佳料重比的SID色氨酸与赖氨酸比值分别为16.6%(95%置信区间:[16.0%,17.3%])和17.1%(95%置信区间:[16.6%,17.7%])。总结:在试验1中(体重6~10 kg阶段的保育仔猪),获得最佳料重比的SID色氨酸与赖氨酸比值为20.4%,获得最佳日增重的SID色氨酸与赖氨酸比值为23.9%。在试验2中(体重11~20 kg阶段的保育仔猪),获得最佳料重比的SID色氨酸与赖氨酸比值为16.6%,获得最佳日增重的SID色氨酸与赖氨酸比值为21.2%。这些结果表明,NRC(2012)的推荐标准可能低估了体重11~20 kg阶段保育仔猪的SID色氨酸与赖氨酸比值。     

日粮消化能与可消化赖氨酸水平对断奶仔猪生产性能的影响

本文旨在研究日粮不同消化能与可消化赖氨酸水平对断奶仔猪生产性能的影响.采用2×3因子设计,以消化能(3500 kcal/kg 与3400 kcal/kg)与可消化赖氨酸水平(1.10%、1.25%和1.40%)为两个主效应.选用288头23日龄断奶健康的杜X长X大三元杂交仔猪[初始体重(6.64±0.39)kg],公母各半,随机分为6个处理,每个处理6个重复,每个重复8头猪,试验期14 d.结果表明:在本试验条件下,与低消化能水平相比,高消化能组显著提高了仔猪日增重(4.6%)和饲料转化率(8.9%)(P＜0.01),降低了日采食量(5%)(P＜0.01).日粮消化能水平对腹泻率无显著影响(P＞0.05).随着日粮赖氨酸水平的提高.断奶仔猪日增重也相应提高(P=0.04).高赖氨酸比低赖氨酸组日增重提高12.4%,饲料转化率也提高5.3%(P＜0.01).日粮赖氨酸水平对日采食量和腹泻率影响并不显著.消化能与赖氨酸互作对试验猪日增重、日采食量、饲料转化率及腹泻率交互作用不明显.综合考虑,日粮消化能水平为3500 kcal/kg,可消化赖氨酸水平为1.25%时,断奶仔猪发挥最大的生长性能,日增重最大,饲料转化率最佳.     

Estimation of the standardized ileal digestible valine-to-lysine ratio in 13- to 32-kilogram pigs

Three experiments were conducted to determine the optimum standardized ileal digestible Val-to-Lys (SID Val:Lys) ratio for 13- to 32-kg pigs. In Exp. 1, 162 pigs weaned at 17 d of age (8 pens/treatment) were used, and a Val-deficient basal diet containing 0.60% l-Lys·HCl, 1.21% SID Lys, and 0.68% SID Val was developed (0.56 SID Val:Lys). Performance of pigs fed the basal diet was inferior to a corn-soybean meal control containing only 0.06% l-Lys·HCl, but was fully restored with the addition of 0.146% l-Val to the basal diet (68% SID Val:Lys). In Exp. 2, 54 individually housed barrows (21.4 kg) were utilized in a 14-d growth assay. Pigs were offered a similar basal diet (1.10% SID Lys), ensuring Lys was marginally limiting with no supplemental l-Val (55% SID Val:Lys). The basal diet was fortified with 4 graded levels of l-Val (0.055% increments) up to a ratio of 75% SID Val:Lys. In Exp. 3, 147 barrows (13.5 kg) were fed identical diets, only with 1 additional level at a SID Val:Lys of 80% and fed for 21 d. In Exp. 2 and 3, a high protein, control diet was formulated to contain 1.10% SID Lys and 0.20% l-Lys·HCl. In Exp. 2, linear effects on ADG (713, 750, 800, 796, and 785 g/d; P = 0.05) and G:F (P = 0.07) were observed with increasing SID Val:Lys, characterized by improvements to a ratio of 65% and a plateau thereafter. In Exp. 3, quadratic improvements in ADG (600, 629, 652, 641, 630, and 642 g/d; P = 0.08) and G:F (P = 0.07) were observed with increasing SID Val:Lys, as performance increased to a ratio of 65% but no further improvement to a ratio of 80%. Pigs fed the control diet did not differ from those fed a ratio of 65% SID Val:Lys in Exp. 2, but did have improved G:F in Exp. 3 (P = 0.03). To provide a more accurate estimate of the optimum SID Val:Lys, data from Exp. 2 and 3 were combined. With single-slope broken-line methodology, the minimum ratio estimate was 64 and 65% SID Val:Lys for ADG and G:F, respectively. With combined requirement estimates, the data indicate that a SID Val:Lys of 65% seems adequate in maintaining performance for pigs from 13 to 32 kg.     

饲粮中不同总赖氨酸与粗蛋白质比例对6.81～11.35千克保育猪生长性能影响

试验研究饲粮中不同总赖氨酸与粗蛋白质比例对282头保育猪(PIC猪TR4×1050)生长性能的影响,确定6.81～11.35千克体重保育猪适宜总赖氨酸与粗蛋白质比例。基础饲粮采用鱼粉作为非必需氨基酸氮源。饲养期持续28天(断奶后3天开始),分为2个生长阶段,0～14天饲喂处理饲粮,14～28天饲喂基础饲粮,试验分为6个处理(总赖氨酸与粗     

Effects of dietary lysine/protein ratio and fat levels on growth performance and meat quality of finishing pigs

This study aimed to evaluate the effects of dietary lysine/protein ratio and fat levels on the growth, carcass characteristics and meat quality of finishing pigs fed feed made from food waste, including noodles and chocolate. Four dietary treatments, 2 levels of lysine/protein ratio (0.035 and 0.046) and 2 levels of fat (3.3% and 6.0%), were adapted to a 2 × 2 factorial arrangement. Each diet for the finishing pigs contained the same levels of adequate crude protein (16%) and lysine (0.58–0.75%), and similar levels of high total digestible nutrients (90.2–92.6%). In total, 32 LWD pigs with an average body weight of 57.2 kg were assigned to 4 dietary groups. The pigs were slaughtered at about 115 kg. Growth performance was not influenced by the dietary treatments. Carcass characteristics were slightly influenced by the dietary fat level. As the dietary lysine/protein ratio decreased, the marbling score of Longissimus dorsi muscle increased and the intramuscular fat (IMF) increased from 6.82% to 9.46%. Marbling score was not significantly influenced by the dietary fat level. These results indicate that IMF increased without adverse effects on growth, carcass characteristics and meat quality, when pigs were fed a diet with low lysine/protein ratio.     

Valine and soleucine requirement of 20- to 45-kilogram pigs

Three experiments were conducted to determine the Val and Ile requirements in low-CP, corn-soybean meal (C-SBM) AA-supplemented diets for 20- to 45-kg pigs. All experiments were conducted for 26 to 27 d with purebred or crossbred barrows and gilts, which were blocked by initial BW. Treatments were replicated with 5 or 6 pens of 3 or 4 pigs per pen. At the beginning of Exp. 1 and the end of all experiments, blood samples were obtained from all pigs to determine plasma urea N (PUN) concentrations. All diets were C-SBM with 0.335% supplemental Lys to achieve 0.83% standardized ileal digestible (SID) Lys, which is the Lys requirement of these pigs. In Exp. 1, 0, 0.02, 0.04, 0.06, 0.08, or 0.10% L-Val was supplemented to achieve 0.51, 0.53, 0.55, 0.57, 0.59, or 0.61% dietary SID Val, and Thr, Trp, Met, and Ile were supplemented to maintain Thr:Lys, Trp:Lys, TSAA:Lys, and Ile:Lys ratios of 0.71, 0.20, 0.62, and 0.60, respectively. Also, supplemental Gly and Glu were added to all diets to achieve 1.66% Gly + Ser and 3.28% Glu, which is equal to the Gly + Ser and Glu content of a previously validated positive control diet that contained no supplemental AA. Treatment differences were considered significant at P < 0.10. Valine addition increased ADG, ADFI, and G:F in pigs fed 0.51 to 0.59% SID Val (linear, P < 0.08), but ADG and ADFI were decreased at 0.61% SID Val (quadratic, P ≤ 0.10). On the basis of ADG and G:F, the SID Val requirement is between 0.56 and 0.58% in a C-SBM diet supplemented with AA. In Exp. 2 and 3, 0, 0.02, 0.04, 0.06, or 0.08% L-Ile was supplemented to achieve 0.43, 0.45, 0.47, 0.49, or 0.51% dietary SID Ile, and Thr, Trp, Met, and Ile were supplemented to maintain Thr:Lys, Trp:Lys, TSAA:Lys, and Val:Lys ratios of 0.71, 0.20, 0.62, and 0.74, respectively. Also, supplemental Gly and Glu were added to achieve 1.66% Gly + Ser and 3.28% Glu as in Exp. 1. Data from Exp. 2 and 3 were combined and analyzed as 1 data set. Daily BW gain, ADFI, and G:F were not affected by Ile additions to the diet; however, ADFI was decreased among pigs fed the diet with 0.45% SID Ile (P < 0.10) compared with pigs fed the 0.43% SID Ile diet. Broken-line analysis requirements could not be estimated for the combined data from Exp. 2 or 3. The results of this research indicate that the SID Val requirement is between 0.56 to 0.58% (0.67 to 0.70 SID Val:Lys), and the Ile requirement is adequate at 0.43% SID Ile (0.52 SID Ile:Lys) for 20- to 45-kg pigs.     

Effects of the standardized ileal digestible lysine to metabolizable energy ratio on performance and carcass characteristics of growing-finishing pigs

A total of 2,121 growing-finishing pigs (Duroc × Landrace × Large White) were utilized in six experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) on the performance and carcass characteristics of growing-finishing pigs. Exps. 1 (30 to 50 kg), 2 (52 to 70 kg) and 3 (81 to 104 kg) were conducted to find an optimum ME level and then this level was used in Exps. 4 (29 to 47 kg), 5 (54 to 76 kg) and 6 (84 to 109 kg) to test the response of pigs to different ratios of SID-Lys:ME. In Exps.1 to 3, four treatments were used consisting of diets with a formulated ME content of 3.1, 3.2, 3.3 or 3.4 in Exps. 1 and 2 while Exp. 3 used 3.05, 3.15, 3.25 or 3.35 Mcal/kg. A constant SID-Lys:ME ratio of 2.6, 2.3 or 2.0 g/Mcal was used in Exps. 1, 2 and 3, respectively. Weight gain was significantly increased with increasing energy level in Exp.1 while weight gain was unaltered in Exps. 2 and 3. For all three experiments, feed intake was decreased (P < 0.05) and feed efficiency was improved (P < 0.05) with increasing energy level. Tenth rib back fat thickness linearly increased (P < 0.05) with increasing energy level. In Exps. 4 to 6, five treatments were used consisting of diets with a SID-Lys:ME ratio of 2.4, 2.6, 2.8, 3.0 or 3.2 in Exp. 1, 2.1, 2.3, 2.5, 2.7, 2.9 or 3.2 in Exp. 2 and 1.8, 2.0, 2.2, 2.4, or 2.6 in Exp. 3. A constant ME level 3.2, 3.2 and 3.05 Mcal/kg was used in Exps. 1, 2 and 3, respectively (selected based on the results of weight gain). For all three experiments, weight gain increased (P < 0.05) and feed efficiency improved linearly (P < 0.05) as the SID-Lys:ME ratio increased. Tenth rib back fat thickness linearly decreased (P < 0.05) as the SID-Lys:ME ratio increased. Based on a straight broken-line model, the estimated SID-Lys:ME ratio to maximize weight gain was 3.0, 2.43 and 2.2 for 29 to 47, 54 to76 and 84 to 109 kg of pigs, respectively.     

不同赖氨酸蛋白质比例对肥育猪氮利用效率的影响

试验选用5头平均体重为60.5kg的杜长大三元杂交猪,研究日粮中赖氨酸与粗蛋白质的比例对肥育猪氮利用效率的影响。日粮中赖氨酸的含量固定为0.8%,按照赖氨酸与粗蛋白质的比例(即4.6%、5.0%、5.6%、6.1%、6.6%)分为5个处理组,采用5×5拉丁方设计。试验结果表明:①赖氨酸与粗蛋白质的比例对粪氮的含量没有影响(P>0.05);②赖氨酸与粗蛋白质的比例对尿氮的含量影响显著(P<0.05);尿氮的含量随氮的摄入量的增加而增加;③氮的沉积和氮的利用效率在赖氨酸与粗蛋白质的比例为5.0%时最大,氮的存留量随日粮粗蛋白质水平的增加而增加(P<0.05),但是赖氨酸与粗蛋白质的比例对干物质和氮的消化率没有影响。     

Effect of dietary energy concentration and apparent ileal digestible lysine:metabolizable energy ratio on nitrogen balance and growth performance of young pigs

Two experiments were conducted to determine the optimal apparent ileal digestible lysine:ME (Lys:ME) ratio and the effects of lysine and ME levels on N balance (Exp. 1) and growth performance (Exp. 2) in growing pigs. Diets were designed to contain Lys:ME ratios of 0.6, 0.7, 0.8, and 0.9 g/MJ at 13.5 and 14.5 MJ of ME/kg of diet in a 4 x 2 factorial arrangement. In Exp. 1, conventional N balances were determined on 48 crossbred barrows (synthetic line 990, initial BW = 13.1 +/- 0.7 kg) at approximately 15, 20, and 25 kg of BW with six pigs per diet. At 15 kg of BW, an energy density x Lys:ME ratio interaction on daily N retention was observed (P < 0.05). At each BW, N retention improved with an increase in N intake associated with increasing ME concentration. In 15-kg BW pigs, increasing the Lys:ME ratio increased daily N retention at the 13.5 (linear, P < 0.001) and 14.5 MJ of ME level (linear, P < 0.01; quadratic, P < 0.05). In 20-kg BW pigs, N retention (g/d) increased (linear, P < 0.001; quadratic, P < 0.01) and N retention (percentage) increased (linear, P < 0.001) as the Lys:ME ratio increased. At 25 kg of BW, N retention (g/d) increased quadratically (P < 0.05) with an increase in Lys:ME ratio. The Lys:ME ratios that maximized daily N retention at 15 kg of BW were 0.88 and 0.85 g/MJ at the 13.5 and 14.5 MJ of ME levels, respectively and 0.81 and 0.77 g/MJ (for both ME levels) at 20 and 25 kg of BW, respectively. Over the 28-d trial, an energy density x Lys:ME ratio interaction on ADG was observed (P < 0.05). Increasing energy density increased growth performance, whereas increasing the Lys:ME ratio in high-energy diets increased ADG (linear, P < 0.05; quadratic, P < 0.01) and gain:feed ratio (G/F) quadratically (P < 0.01). Average daily gain and G/F ratio were greatest in pigs fed the 14.5 MJ of ME diet and the Lys:ME ratio of 0.82 g/MJ. In Exp. 2, 128 individually housed crossbred barrows and gilts (initial BW = 12.8 +/- 1.6 kg) were used to determine the effect of diets used in Exp. 1 on growth performance in a 4 x 2 x 2 factorial arrangement. The ME level increased ADG and G/F from d 0 to 14 and from d 0 to 28. Increasing the Lys:ME ratio increased ADG from d 0 to 14, whereas growth performance was maximized in pigs fed Lys:ME ratio of 0.82 g/MJ. These results suggest that pigs from 13 to 20 and from 20 to 30 kg of BW fed diets containing 14.5 MJ of ME/kg had maximum N retention and ADG at 0.85 and 0.77 g of apparent ileal digestible lysine/MJ of ME, respectively.     

Effects of porcine circovirus type 2 vaccine and increasing standardized ileal digestible lysine:metabolizable energy ratio on growth performance and carcass composition of growing and finishing pigs

Four experiments were conducted to examine the effect of porcine circovirus type 2 (PCV2) vaccination on the response of growing and finishing pigs (PIC 337 × 1050) to increasing dietary Lys. Experiments 1 and 2 evaluated 38- to 65-kg gilts and barrows, respectively, and Exp. 3 and 4 evaluated 100- to 120-kg gilts and barrows, respectively. Gilts and barrows were housed separately in different barns. Treatments were allotted in a completely randomized design into 2 × 4 factorials with 2 PCV2 treatments (PCV2-vaccinated and nonvaccinated) and 4 standardized ileal digestible (SID) Lys:ME ratios (2.24, 2.61, 2.99, and 3.36 g/Mcal in Exp. 1 and 2 and 1.49, 1.86, 2.23, and 2.61 g/Mcal in Exp. 3 and 4) within each experiment. There were 5 pens per treatment. At the start of Exp. 1 and 2, there were more pigs per pen (P < 0.001) in vaccinated pens because vaccinated pigs had a greater survival rate than nonvaccinated pigs, and this increase was maintained throughout the experiments. Removal rate approached 30% in nonvaccinated barrows and more than 20% in nonvaccinated gilts. Observation suggested that the removals were largely due to PCV2-associated disease. No PCV2 vaccination × SID Lys:ME ratio interactions (P > 0.10) were observed in any of the 4 studies. In Exp. 1 and 2, PCV2-vaccinated pigs had increased (P < 0.001) ADG compared with nonvaccinated pigs. The growth response was primarily due to increases in ADFI, which suggests that vaccinated pigs have a greater Lys requirement (g/d) than nonvaccinated pigs. In Exp. 1, increasing the SID Lys:ME ratio increased (quadratic; P < 0.04) ADG and G:F, with pigs fed the 2.99 g/Mcal ratio having the greatest ADG and G:F. In Exp. 2, increasing the SID Lys:ME ratio improved (linear; P < 0.001) G:F. In Exp. 3, ADG and G:F increased (P < 0.05) in a quadratic manner as the SID Lys:ME ratio fed increased. In Exp. 4, increasing the SID Lys:ME ratio increased ADG (linear; P < 0.001) and G:F (quadratic; P = 0.03). Although PCV2 vaccination improved growth, the corresponding increase in ADFI did not increase the optimal SID Lys:ME ratio for growing and finishing barrows and gilts.     

Effect of dietary protein source and lysine:DE ratio on growth performance, meat quality, and body composition of growing-finishing pigs.

The effects of four protein sources (soybean meal, sunflower meal, pea, and fish meal as the main protein source) and three apparent ileally digestible Lys:DE ratios (0.50, 0.43, 0.36 and 0.42, 0.36, 0.30 g Lys/MJ DE for 30 to 60 kg BW and 60 to 105 kg BW, respectively) in pig diets on growing-finishing performance, and carcass and meat quality traits were investigated. Eight individually housed animals per treatment received the diets from 30 to 105 kg BW at a level of 3.0 times maintenance requirements of energy. The ileal digestibility of protein sources was determined in a previous digestibility experiment. Protein sources showed no differences in growth performance from 30 to 105 kg BW. From 30 to 60 kg BW soybean treatment had lowest performance. The protein sources had no effect on lean meat percentage, liver weight, or meat quality (intramuscular fat content, pH at 45 min and 24 h after slaughter, drip loss, and meat color measured 24 h and 4 d after slaughter). The experimental diets formulated on the basis of similar apparent ileal digestible lysine content resulted in similar body composition regardless of the protein source used (P > 0.05). Reducing the Lys:DE ratio from 0.50/0.43 to 0.36/0.30 (by about 28%) reduced BW gain by 119 g/d from 30 to 60 kg and by 151 g/d from 60 to 105 kg BW. The gain:feed ratio increased by 82 g/kg in the first phase and by 47 g/kg in the second phase for the highest Lys:DE treatment compared with the lowest. Reducing Lys:DE ratio did not modify meat quality traits. A high Lys:DE ratio was associated with a high lean meat percentage. Differences between the medium- and low-Lys:DE groups were not significant. Lowering the Lys:DE ratio increased (P < 0.05) crude fat and fatty tissue content and decreased (P < 0.05) protein and muscle content in the body. Ash content and bone volume were not affected by Lys:DE ratio (P > 0.05). The chemical composition of the carcass can be predicted with moderate accuracy (R2 = 0.39 to 0.58) using volumetric composition data of previously frozen carcasses. In conclusion, similar growth performance, carcass and meat quality, and body composition can be expected if diet formulation is based on the apparent ileally digestible amino acid contents of feedstuffs, independent of dietary protein sources. Diminishing Lys:DE ratios reduce growth performance but do not modify meat quality traits. The chemical composition of the carcass can be predicted with moderate accuracy using the volumetric composition of thawed carcasses.     

半胱胺对育肥猪生产性能的影响

动物的生长发育受神经内分泌系统的调节，而其中最重要的是由下丘脑-垂体-靶腺构成的神经内分泌生长轴（the somatotropic axis）。生长激素（Growth Hormone，GH）是该调控的核心，它能够促进肌肉组织蛋白质的合成，抑制脂肪组织葡萄糖的摄入和脂肪的合成。生长抑素（Somatostatin，SS）是由神经系统和胃肠道产生的，     

Effect of apparent ileal digestible lysine to energy ratio on performance of finishing pigs at different dietary metabolizable energy levels

A study with a total of 96 crossbred barrows and gilts fed ad libitum in a body weight range of 56-110 kg was carried out in order to investigate whether the optimum ratio of apparent ileal digestible lysine : energy (ME) depends on the energy density of the diet. Dietary treatments were ratios of 0.34, 0.42, 0.50 and 0.58 g digestible lysine/MJ ME either at an energy density of 13 or 14 MJ ME. Body weight gain as well as feed and ME conversion rate were improved when lysine : ME ratio increased from 0.34 to 0.50, whereby all parameters showed a significant ratio x sex interaction. Feed intake and feed conversion rate were higher at a dietary energy density of 13 MJ ME than at an energy density of 14 MJ ME but energy density did not influence daily growth rate, ME intake and ME conversion rate. Fat area above eye muscle and meat : fat ratio were lower and eye muscle area and lean percentage were higher at a ratio of 0.42 compared with a ratio of 0.34. Daily feed intake, body weight gain, feed conversion rate and parameters of fatness were higher in barrows than in gilts. Conversely, gilts had higher eye muscle area and lean percentage. Optimum ratio for body weight gain, feed and ME conversion rate calculated by exponential regression analysis were 0.42-0.43 in barrows. In gilts, feed and ME conversion rate were optimized at a ratio of 0.53 and 0.54. Because growth showed a linear response to increasing digestible lysine : ME ratios, optimum ratio for daily gain in gilts is considered to be at least 0.58.     

日粮能量蛋白质与赖氨酸水平对5～10周龄扬州鹅生长性能的影响

试验旨在研究日粮不同能量蛋白质水平和赖氨酸水平对5~10周龄扬州鹅生长性能的影响。试验采用3×4二因子设计,3个能量蛋白质水平分别为:10.83 MJ/kg、15%,11.29 MJ/kg、16%,11.75 MJ/kg、17%,其蛋白质能量比均约为14 g/MJ,4个赖氨酸水平分别为:0.65%、0.80%、0.95%和1.10%。结果表明:①日粮能量蛋白质水平对6、8、10周龄扬州鹅体重没有显著影响(P>0.05),日粮赖氨酸水平显著影响扬州鹅6、8、10周龄体重(P<0.05),但能量蛋白质水平和赖氨酸水平对其没有显著交互作用(P>0.05);②日粮能量蛋白质水平显著影响5~10周龄扬州鹅的平均日采食量和料重比(P<0.05),赖氨酸水平显著影响平均日增重和平均日采食量(P<0.05),能量蛋白质水平和赖氨酸水平对其没有显著交互作用(P>0.05);③中能蛋水平和最低赖氨酸水平下,5~10周龄扬州鹅可获得较佳生长性能。试验认为5~10周龄扬州鹅能量蛋白质和赖氨酸适宜需要量分别为11.29 MJ/kg、16%和0.65%。     

液态饲喂在育肥猪上的使用效果

为研究饲料液态饲喂对育肥猪生长性能和经济效益的影响,试验选用体重为(82.93±3.35) kg的"杜×长×大"(Duroc×Landrace×Yorkshire)三元杂交猪300头,随机分为3组,每组5个重复,每个重复20头猪,试验期为31 d,对照组饲喂固体颗粒饲料,试验A组用对照组日粮加水饲喂,试验B组日粮由干料、过期酸奶、水按比例配制而成,干基营养水平与对照组相当。试验结果表明:相比对照组,试验A组的平均日增重、平均日采食量分别提高了6.9%和2.1%,料重比降低了4.3%,但两组之间差异不显著;试验B组的平均日增重与对照组相当,平均日采食量、料重比分别降低了6.3%(P<0.05)和6.4%(P>0.05);同时,饲喂液态料的两个试验组经济效益均有不同程度提高。     

Effects of continual fluctuation in feed intake on growth performance response and carcass fat-to-lean ratio in grower-finisher pigs

An experiment was conducted to examine the effect of continual fluctuations in feed intake on grower-finisher pig growth performance and carcass fat-to-lean ratio (F:L). Sixty individually housed female pigs (Landrace x Large White) with initial BW of 29.8 +/- 0.4 kg were randomly allocated to 1 of 4 feeding regimens (n = 15): 1) ad libitum throughout (AL); 2) 85% of the mean intake of the AL group during the previous week (R); 3) 70% of the mean intake on 1 d, and on the following day, 100% of the amount consumed by the AL group during the preceding week, with this pattern repeated every 2 d throughout (D); and 4) 70% of the mean intake for 3 consecutive days, and 100% of the amount consumed by the AL group for the next 3 d, with this pattern repeated throughout the experiment (3-D). Pigs receiving each treatment were fed the same diets during the weaner (10 to 20 kg), grower (20 to 50 kg), finisher 1 (50 to 70 kg), and finisher 2 (70 kg to slaughter at approximately 104 kg) growth phases. Pigs receiving fluctuated feed intake either by the D or 3-D feeding regimen showed a pattern of growth similar to that of pigs on the R feeding regimen. Pigs on the R and 3-D regimens were lighter at 28 d (P < 0.05) and pigs on the R, D, and 3-D regimens were lighter at 63 d (P < 0.05) than pigs on the AL regimen. Pigs on the R, D, or 3-D feeding regimens had a greater G:F between 15 to 42 d of the experiment than pigs fed AL throughout (P < 0.05). The R, D, and 3-D feeding regimens seemed to have some effect on carcass weight and dressing percentage, and pigs had a decreased P2 (located 65 mm from the midline of the carcass at the last thoracic rib) backfat depth (P < 0.05) compared with pigs fed AL. Pigs on the AL and 3-D feeding regimens had thicker subcutaneous fat at the last lumbar vertebrae on the dorsal edge of the loin than pigs on the R feeding regimen (P < 0.05). Carcass and visceral fat content and the F:L in the carcass and primal cuts, as measured by dual energy x-ray absorptiometry, were not different among treatments. However, pigs on the AL and 3-D feeding regimens had decreased estimated bone content in the carcass compared with pigs on the R and D feeding regimens (P < 0.05). The results indicated that continual fluctuation in feed intake either every other day or every 3 d had minimal effects on growth and carcass F:L compared with pigs fed the same restricted amount throughout the experiment.     

Influence of the dietary ratio between sulphur containing amino acids and lysine on performance of growing-finishing pigs fed diets with various lysine concentrations.

This study was conducted to determine the optimal ratio between sulphur containing amino acids and lysine in diets for growing-finishing pigs. Therefore, a total of five trials was carried out in which growing-finishing pigs (live weight range between 53 and 105 kg) were fed diets with various concentrations of lysine (0.62, 0.70 and 0.78%) and various ratios between sulphur containing amino acids to lysine. The diets contained 12.9 MJ ME per kg and 13.5% CP; the ratio between sulphur containing amino acids to lysine was adjusted by individual supplementation of the diets with DL-methionine. Increasing dietary levels of lysine from 0.62 to 0.78% continuously increased daily body weight gains and improved feed conversion efficiency as well as carcass characteristics. There was no significant interaction between the dietary lysine supply and the ratio between sulphur containing amino acids to lysine on animal performance parameters. This means that the effect of the ratio of sulphur containing amino acids to lysine was similar for various dietary lysine concentrations. The optimum ratio between sulphur containing amino acids to lysine according to quadratic regression analysis was 0.60, for both, growth and feed conversion. Reducing the ratio between sulphur containing amino acids to lysine from 0.59 to 0.53 and 0.47 reduced body weight by 3 and 12%, resp., and elevated the feed conversion ratio by 2 and 12%, resp. An increase of the ratio between sulphur containing amino acids to lysine from 0.59 to 0.65 failed to increase the animal performance. In contrast to animal performance parameters, optimum carcass characteristics (eye muscle area, fat area above eye muscle, meat-fat ratio and lean percentage) were achieved already at a ratio of sulphur containing amino acids to lysine of 0.53.     

Determining an optimum lysine:calorie ratio for barrows and gilts in a commercial finishing facility

Our objective was to determine an optimum Lys:calorie ratio (g of total dietary Lys/Mcal of ME) for 35- to 120-kg barrows and gilts (Pig Improvement Company, L337 x C22) in a commercial finishing environment. Seven (3 barrow and 4 gilt) trials were conducted using randomized complete block designs (42 pens per trial, a total of 7,801 pigs). Six treatments with increasing Lys:calorie ratio were used in each study. Diets were corn-soybean meal-based with 6% choice white grease. Lysine:calorie ratios were attained by adjusting the amount of corn and soybean meal. No crystalline Lys was used. In barrow trial 1 (43 to 70 kg), increasing the Lys:calorie ratio (2.21, 2.55, 2.89, 3.23, 3.57, and 3.91) increased (quadratic, P < 0.01) ADG, G:F, income over feed costs (IOMFC), and feed cost per kilogram of gain, and decreased (linear, P < 0.01) backfat. In barrow trial 2 (69 to 93 kg), increasing the Lys:calorie ratio (1.53, 1.78, 2.03, 2.28, 2.53, and 2.78) improved (linear, P < 0.01) ADG, G:F, and IOMFC, and decreased (quadratic, P < 0.01) backfat. In barrow trial 3 (102 to 120 kg), increasing the Lys:calorie ratio (1.40, 1.60, 1.80, 2.00, 2.20, and 2.40) increased (linear, P < 0.03) ADG and G:F, and numerically improved (linear, P = 0.12) IOMFC. In gilt trials 1 (35 to 60 kg), 2 (60 to 85 kg), and 3 (78 to 103 kg), increasing the Lys:calorie ratio (2.55, 2.89, 3.23, 3.57, 3.91, and 4.25; 1.96, 2.24, 2.52, 2.80, 3.08, and 3.36; and 1.53, 1.78, 2.03, 2.28, 2.53, and 2.78, respectively) improved (quadratic, P < 0.04) ADG, G:F, IOMFC, and feed cost per kilogram of gain, and decreased (linear, P < 0.01) backfat. In gilt trial 4 (100 to 120 kg), increasing the Lys:calorie ratio (1.40, 1.60, 1.80, 2.00, 2.20, and 2.40) improved (linear, P < 0.02) ADG, G:F, LM depth, IOMFC, and (quadratic, P < 0.06) feed cost per kilogram of gain. These studies suggest that feed cost per kilogram of gain decreases, and reductions in biological performance and IOMFC are rather modest when feeding marginally Lys-deficient diets early (35 to 70 kg) in the grower-finishing period compared with the more severe penalties in growth and economic performance of feeding marginally deficient diets in the late finishing period (70 kg to slaughter). The equations (Lys:calorie ratio = -0.0133 x BW, kg, + 3.6944 and = -0.0164 x BW, kg, + 4.004, for barrows and gilts, respectively) best describe our interpretation of the Lys:calorie ratio that met biological requirements and optimized IOMFC on these pigs (PIC, L337 x C22; 35 to 120 kg) in this commercial finishing environment.     

Estimation of the ideal ratio of true ileal digestible sulfur amino acids:lysine in 8- to 26-kg nursery pigs

Four experiments were conducted to determine the ideal ratio of true ileal digestible (TID) sulfur AA to Lys (SAA:LYS) in nursery pigs at two different BW ranges using both DL-Met and 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) as Met sources. In Exp. 1, 1,549 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 8.3 +/- 0.08 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a semicomplex corn-soybean meal-based diet (1.32% TID Lys) with no supplemental HMTBA or DL-Met (47.7% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (52.7, 57.7, 62.7, and 67.7% TID SAA:LYS). In Exp. 2, 330 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 11.4 +/- 0.10 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.15% TID Lys) with no supplemental HMTBA or DL-Met (49% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (54, 59, 64, and 69% TID SAA:LYS). In Exp. 3, 1,544 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 12.4 +/- 0.13 kg) were allotted to one of nine dietary treatments as in Exp. 2. In Exp. 4, 343 nursery pigs (Genetiporc; initial BW 12.8 +/- 0.56 kg) were allotted to one of six dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.05% TID Lys) with no supplemental DL-Met (49% TID SAA:LYS). Diets 2 to 5 consisted of the basal diet supplemented with four levels of DL-Met (54, 59, 64, and 69% TID SAA:LYS), and Diet 6 was the basal diet supplemented with one equimolar level of HMTBA to satisfy 59% TID SAA:LYS ratio. In all experiments, increasing the TID SAA:LYS ratio resulted in quadratic improvements in ADG (P < or = 0.09) and G:F (P < or = 0.05). Three different methods were used to estimate the optimal TID SAA:LYS ratio for each experiment. The two-slope broken-line regression model, x-intercept value of the broken-line and quadratic curve, and 95% of upper asymptote across the four experiments indicated that the average optimal TID SAA:LYS ratios were 59.3, 60.1, and 57.7% for ADG and 60.6, 61.7, and 60.1% for G:F, respectively. Thus, the optimal TID SAA:LYS ratio for 8- to 26-kg pigs based on the average value of these three estimates was 59.0% for ADG and 60.8% for G:F.