浓缩菜籽蛋白的营养价值及养猪效果

对广汉县新开发的浓缩菜籽蛋白饲料(CRP)作了营养成分和毒性成分分析以及饲喂断奶生长猪的效果观察。结果表明:浓缩菜籽蛋白的粗蛋白含量较普通菜籽饼提高40.86％(40.33比56.81％,全干基础);赖氨酸等主要必需氨基酸含量也有较大幅度增加;主要毒素异硫氰酸盐、恶唑烷硫酮去除量达95％。在能量、蛋白质相等的饲粮中,浓缩菜籽蛋白可以代替生长猪饲粮6％的蚕蛹。尽管浓缩菜籽蛋白饲料的价格比普通菜籽饼高2.75倍(0.90比0.24元/公斤),但最终饲养经济效益却比后者高10.78％。作者认为为,CRP是一种新的优质蛋白质饲料。     

发酵菜籽饼蛋白饲料饲喂瘦肉型猪效果观察

发酵菜籽饼蛋白饲料,蛋白质含量高达45.38％,适口性好,用其取代饲料中鱼粉(3组)、豆粕(2组),或作为猪饲粮中唯一蛋白质饲料源(1组)饲喂瘦肉型生长肥育猪,与含鱼粉 豆粕的饲粮(4组)比较,日增重差异不显著(P>0.05)。即使日粮中配以高达27.5％的发酵菜籽饼蛋白饲料,猪只仍采食正常,无任何肉眼可见的中毒症状。经屠宰测定,1—3组胴体瘦肉率、背膘厚度、眼肌面积和后腿比例等指标,与4组比差异均不显著(P>0.05)。说明用发酵菜籽饼蛋白饲料部分或完全代替饲粮中的鱼粉、豆粕喂猪,有安全、等效、来源广、成本低的效果。     

饲粮中不同菜籽饼比例对雏鸡生长的影响

以不同比例(6、9、12、15、18、21％)的菜籽饼(RSM)代替部分豆饼(SBM)的饲粮喂成都白鸡,从10日龄起连喂四周。结果表明:饲粮中用6～21％菜籽饼代替部分豆饼增重显著下降;在含菜籽饼12％以下时,饲料利用率与豆饼组差异不显著(P>0.05)。饲菜籽饼的各组均使甲状腺、肝和肾的重量增大。     

低蛋白饲粮平衡有效赖氨酸对生长肥育猪生产性能的影响

<正> 前言 菜籽饼是我国产量大、价格廉的一种蛋白质资源。由于和豆饼相比,口粮中添加菜籽饼,猪的生产性能下降,致使其使用受到了限制。菜籽饼中氨基酸不平衡是其饲用效果较差的重要原因之一〔2、9、10〕。根据氨基酸平衡理论在菜籽饼日粮中补加赖氨酸没有取得一致效果〔1、2、3〕。Tanskley(1984)〔9〕建议,在使用氨基酸利用率不同于玉米——豆饼日粮的饲料时,必须考虑其氨基酸的有效性来配制饲粮。因此,本试验目的是研究以菜籽饼作为主要蛋白质补充料,在低饲粮蛋白水平情况下,改善饲粮有效赖氨酸平衡对生长肥育猪生产性能的影响和节约蛋白质效果。     

过量的粗蛋白质对未孕青年母猪的影响

选用25头未孕的杂交青年母猪(平均始重126公斤),用完全随机设计、按系谱和体重将其分配到5个处理组。第1组自由采食高蛋白(38％)饲粮;第2组按每天1.82公斤饲喂高蛋白(38％)饲粮;第3组自由采食低蛋白(13％)饲粮;第4组按每天1.82公斤饲喂低蛋白(13％)饲粮;第5组为配对饲养组,按自由采食高蛋白饲粮青年母猪头一天的平均采食量饲喂13％粗蛋白饲粮。试验期为30天。采用玉米-豆饼饲粮,用改变玉米:豆饼比例的方法来调整饲粮粗蛋白含量。     

脱毒菜籽饼对鸡饲养效果的评价——Ⅲ.脱毒菜籽饼-玉米型肉仔鸡饲粮的研究

用明星肉仔鸡420只研究了脱毒菜籽饼-玉米型饲粮的应用问题。试验设置8种饲粮,高能和低能各4种,脱毒菜籽饼代替豆饼的比例为:0,20,50,75和100%。试验结果表明:(1)脱毒菜籽饼对肉用仔鸡无毒害作用,适口性好,在保持饲粮营养水平一致时,能以任何比例替代饲粮中的豆饼,(2)肉仔鸡饲粮中赖氨酸:精氨酸的比值对饲粮的利用率有较大的影响,脱毒菜籽饼-玉米型肉仔鸡饲粮尤应重视精氨酸的不足;(3)在低能无鱼粉饲粮中,脱毒菜籽饼与豆饼配伍,可以取得较好的效果。     

菜籽饼和脱毒菜籽饼对雏鸡的病理损害

在饲料中加入不同量的菜籽饼或脱毒菜籽饼作饲料喂雏鸡试验,以病理组织学方法观察菜籽饼毒素对雏鸡体内主要器官的损害。结果表明,菜籽饼和脱毒菜籽饼均能引起雏鸡器官的病理损害。其组织学变化,与上述物质饲喂猪、鸭所引起的病变一致。同时表明,在饲料中添加２．５％ 菜籽饼或７．５％ 脱毒菜籽饼,仍不是安全的做法。     

不同比例的菜籽饼替代豆粕对仔猪增重的影响

菜籽饼蛋白质含量高达35％～37％，且氨基酸组成与理想蛋白相接近，因而在蛋白质饲料开发利用中日益受到人们的重视。在青海省菜籽饼量多价廉，是重要的蛋白质资源，但由于菜籽饼含有硫甙(芥子甙)、植酸、单宁和芥子碱等抗营养因子，限制了其在仔猪饲粮中的应用。一般多用于生长育肥猪，在仔猪饲粮中的应用甚少。为了充分利用饲料资源，缓解蛋白质饲料不足的状况，进行了以不同比例的菜籽饼蛋白等量替代     

仔猪饲粮添加大豆油脚效果观察

<正> 仔猪对饲粮能量要求要高于生长育肥猪,尤其是早期断奶的仔猪。据苏报导,4～5周龄断奶仔猪阔粮中应含:DE3.41—3.5兆卡/公斤,CP20—22％,脂肪含量达4—6％至8—10％。 我们于1987年秋季进行了在10-20公斤时仔猪饲粮中添加油脚试验,试验结果表明:当在10—20公斤仔猪饲粮中添加8％的油脚时,全期增重比对照组提高17.62％,每增重公斤活重节省饲料12.77％。大豆油脚作为脂肪填充物,添加在仔猪饲粮中(一)为幼畜提供必须脂肪酸和磷脂及V_E,(二)对提高饲粮能量浓度,加快仔猪生长速度,降低饲料消耗,提高养猪生产经济效益是极为有益。     

菜籽饼和棉仁饼对饲粮中矿物质有效性的影响

菜籽饼和棉仁饼是我国仅次于豆饼的另两类丰富的蛋白质饲料资源.美国NRC中鸡的营养需要量是按玉米-豆饼型饲粮制订的,而我国鸡的营养需要量标准,又主要引自美国NRC.所以,这样的营养需要量、能否应用于含有菜籽饼和棉仁饼的饲粮,则必须进行生物学有效性差异的试验研究.这对于我国养鸡生产中合理利用各地饼类蛋白饲料资源,具有重要意义.然而,目前国内外这方面的报道却很少见.本次试验的目的,是研究以菜籽饼和棉仁饼分别代替玉米-豆饼型饲粮中1/2豆饼     

Influence of dietary protein, fat or amino acids on the response of weanling swine to aflatoxin B1

Two experiments were conducted using corn from clean or aflatoxin B1 (AFB1)-contaminated (182 ppb) sources. Weanling pigs (28 d) were fed one of eight dietary treatments arranged in a 2 x 2 x 2 factorial design. In Exp. 1 (192 pigs), treatments varied in corn source (clean or AFB1-contaminated), CP level (18 or 20%) and added fat (0 or 5%). At the end of the 28-d growth trials, plasma samples were obtained. An AFB1 x CP level interaction was detected (P less than .05) for growth rate (ADG), feed intake (FI) and feed/gain ratio (F/G). Feeding AFB1 reduced (P less than .05) ADG (.30 vs .37 kg/d) and FI (.57 vs .66 kg/d) and increased F/G (1.88 vs 1.78) of pigs fed 18% CP diets. Performance of pigs fed 20% CP diets was not altered by AFB1. Adding 5% fat to diets improved (P less than .05) F/G but did not improve ADG of pigs fed AFB1. There was an AFB1 x CP x fat interaction (P less than .05) for plasma cholesterol. Adding fat or increasing the CP level prevented the depression of plasma cholesterol in pigs fed AFB1. In Exp. 2 (96 pigs), all diets contained 18% CP and the treatments varied in corn source (clean or AFB1-contaminated), added L-lysine HCl (0 or .25%) and added DL-methionine (0 or .15%). Feeding AFB1 reduced (P less than .05) ADG of pigs fed the 18% CP diet (.44 vs .50 kg/d) but not of pigs fed diets supplemented with .25% lysine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cereal type and heat processing of the cereal affect nutrient digestibility and dynamics of serum insulin and ghrelin in weanling pigs

The effects of feeding corn or rice, either raw or heat processed (HP), on apparent total tract digestibility (ATTD) and apparent ileal digestibility (AID) of nutrients and on insulin and ghrelin concentrations in the serum were studied in young pigs. Pigs were weaned at approximately 23 ± 3 d of age and weighed 7.4 ± 1.2 kg. Each of the 4 treatments was replicated 9 times, and the experimental unit was a pig individually housed. Pigs (5 males and 4 females/treatment) were fed their respective diets ad libitum from 23 to 47 d of age. At 37 d of age, the effects of dietary treatments on the fasting and postprandial concentrations of insulin and total and acylated ghrelin were studied. The ATTD of OM, GE, and ether extract were, respectively, 4.3, 5.4, and 3.6% greater (P < 0.05) for the rice than for the corn diets, but CP digestibility was not affected. Similar results were observed for AID. Heat processing of the cereal increased (P < 0.05) the ATTD by 2.1% for OM, 3.2% for GE, 7.1% for ether extract, and 2.2% for CP and tended to increase the AID of CP (P = 0.06) and starch (P = 0.09). The postprandial serum insulin response was greater and was more prolonged in pigs fed raw rice than in pigs fed raw corn (P < 0.05). In addition, the effects of HP on serum insulin response were more pronounced with corn than with rice (cereal × HP, P < 0.05). Total ghrelin concentration was not affected by treatment, but acylated ghrelin was greater (P < 0.05) at 6 h postprandially in pigs fed rice than in pigs fed raw corn. Feeding rice and HP corn increased nutrient digestibility and insulin response in the early postprandial period and increased the acylated ghrelin response in the late postprandial period compared with feeding raw corn.     

Assessment of the feeding value of South Dakota-grown field peas (Pisum sativum l.) for growing pigs

Four experiments were conducted to investigate the feeding value of South Dakota-grown field peas (Pisum sativum L.) for growing pigs. In Exp. 1, 96 pigs (initial BW = 22 +/- 3.35 kg) were allotted to four treatment groups (four pigs per pen, six replicate pens per treatment) and fed growing (0.95% Lys) and finishing (0.68% Lys) diets containing 0, 12, 24, or 36% field peas (as-fed basis). There were no differences among the treatment groups in ADG, ADFI, or G:F. Likewise, there were no differences in backfat thickness or lean meat percent among treatment groups, but pigs fed diets containing 12, 24, or 36% field peas had greater (P < 0.05) loin depths than pigs fed the control diet. In Exp. 2, 120 pigs (initial BW = 7.8 +/- 1.04 kg) were allotted to four treatment groups 2 wk after weaning. Pigs were then fed diets containing 0, 6, 12, or 18% field peas (as-fed basis) during the following 4 wk. There were five pigs per pen and six replicate pens per treatment. Results of the experiment showed no differences in ADG, ADFI, or G:F among treatment groups. In Exp. 3, apparent (AID) and standardized (SID) ileal digestibility coefficients of CP and AA in field peas and soybean meal were measured using six individually penned growing pigs (initial BW = 36.5 +/- 2.1 kg) arranged in a repeated 3 x 3 Latin square design. The AID for Met, Trp, Cys, and Ser, and the SID for Met, Trp, and Cys were lower (P < 0.05) in field peas than in soybean meal; but for CP and all other AA, no differences in AID or SID were observed between the two feed ingredients. Experiment 4 was an energy balance experiment conducted to measure the DE and ME concentrations in field peas and corn. Six growing pigs (initial BW = 85.5 +/- 6.5 kg) were placed in metabolism cages and fed diets based on field peas or corn and arranged in a two-period switch-back design. The DE values for field peas and corn (3,864 and 3,879 kcal/kg DM, respectively) were similar, but the ME of corn was higher (P < 0.05) than the ME of field peas (3,825 vs. 3,741 kcal ME/kg DM). The results from the current experiments demonstrate that the nutrients in South Dakota-grown field peas are highly digestible by growing pigs. Therefore, such field peas may be included in diets for nursery pigs and growing-finishing pigs in amounts of at least 18 and 36%, respectively, without negatively affecting pig performance.     

Effects of feeding diets containing low crude protein and coarse wheat bran as alternatives to zinc oxide in nursery pig diets

Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance.     

Additivity of values for apparent and standardized ileal digestibility of amino acids in mixed diets fed to growing pigs

The objective of this experiment was to determine whether the digestibility of CP and AA in a mixed diet fed to growing pigs is better predicted when based on standardized ileal digestibility coefficients (SID) or apparent ileal digestibility coefficients (AID). Eight growing pigs (initial BW = 92.1 +/- 3.19 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in an 8 x 8 Latin square design with eight diets and eight periods. Three of the diets contained corn, soybean meal (SBM), or canola meal (CM) as the sole source of CP and AA. Four mixed diets also were formulated using corn and soybean meal (CS); corn and canola meal (CCM); soybean meal and canola meal (SCM); or corn, soybean meal, and canola meal (CSCM). A N-free diet was used to measure the basal ileal endogenous losses (IAAend) of CP and AA. Pigs were fed each of the eight diets during one 7-d period, and ileal digesta were collected during two 10-h periods on d 6 and 7. The AID values were calculated for CP and AA in all diets, except the N-free diet. By correcting the AID for IAAend, the SID for CP and AA in each of the seven protein-containing diets were calculated. As expected, the AID for CP and the majority of AA were greater in SBM than in corn and CM (P < 0.05); however, the SID for CP and most AA did not differ between corn and SBM. For the majority of the AA, SID were less (P < 0.05) in CM than in the other two ingredients. Using the AID and the SID that were measured for CP and AA in corn, SBM, and CM, the AID and the SID in the four mixed diets were predicted and compared with the measured values for these diets. For the three mixed diets containing corn, the measured AID for CP and most AA were greater (P < 0.05) than the predicted AID, but with a few exceptions, no differences between predicted and measured values for SID were observed. For the diet based on SCM, there were no differences between predicted and measured values regardless of the procedure used, except for the AID of Ser. The results of this experiment demonstrate that the digestibility coefficients for a mixed diet containing low-protein feed ingredients, such as corn, are more accurately predicted using SID than AID.     

Glycemic index of starch affects nitrogen retention in grower pigs

Three studies were performed to examine the effect of starch and protein digestion rates on N retention in grower pigs. In Exp. 1, the glycemic index (GI) of corn, a malting barley, and a slow-rumen-degradable barley (SRD-barley) were measured using 6 barrows (BW = 18.0 ± 0.5 kg). The GI of malting barley was greater (P < 0.05) than that of SRD-barley (71.1 vs. 49.4), and the GI of both barley cultivars was less (P < 0.05) than that of corn (104.8). In Exp. 2, the standardized ileal digestibility of AA and DE content of the 3 ingredients were determined using 5 ileal-cannulated barrows (BW = 20.7 ± 2.3). The apparent total-tract energy digestibility values of corn (86.1%) and malting barley (85.7%) were greater (P < 0.05) than that of SRD-barley (82.3%). The standardized ileal digestibility of Lys was 94.0, 92.6, and 92.4% for corn, malting barley, and SRD-barley, respectively, and did not differ among grains. In Exp. 3, 6 diets were formulated to equal DE (3.40 Mcal/kg), standardized ileal digestibility of Lys (8.6 g/kg), starch (424.9 g/kg), and digestible CP (180.0 g/kg) using the values obtained in Exp. 2. Three GI [high (corn), medium (malting barley), and low (SRD-barley)] and 2 rates of protein digestion [rapid (soy protein hydrolysate) and slow (soy protein isolate)] were tested in a 3 × 2 factorial arrangement with 36 barrows (BW = 32.2 ± 2.5 kg). Pigs were fed 3.0 times the maintenance energy requirement daily in 2 meals for 2 wk and were housed in metabolic crates to collect feces and urine separately. At the end of the study, intestinal contents were collected from 4 equal-length segments of the small intestine. The percentage of unabsorbed CP in segment 1 relative to dietary CP was greater (P < 0.05) for the soy protein isolate diet than for the soy protein hydrolysate diet (170.3 vs. 116.5%). The percentages of unabsorbed starch in segments 1 and 2 were greater (P < 0.05) for the SRD-barley diet than for the malting barley or corn diet. Nitrogen intake and fecal N excretion were greater (P < 0.05) for pigs fed the malting barley and SRD-barley diets than for pigs fed the corn diet. Urinary N excretion was greater (P < 0.05) for pigs fed the SRD-barley diet than for pigs fed the corn or malting barley diet. Pigs fed slowly digestible starch (SRD-barley; 46.6%) had less (P < 0.05) net N retention than pigs fed corn or malting barley (54.7 and 54.1%, respectively). In conclusion, slowly digestible starch sources such as SRD-barley may not be suitable to support maximum protein deposition in restricted-fed grower pigs.     

Energy, phosphorus, and amino acid digestibility of high-protein distillers dried grains and corn germ fed to growing pigs

Three experiments were conducted to measure energy, P, and AA digestibility in 2 novel co-products from the ethanol industry [i.e., high-protein distillers dried grains (HP DDG) and corn germ]. These products are produced by dehulling and degerming corn before it enters the fermentation process. Experiment 1 was an energy balance experiment conducted to measure DE and ME in HP DDG, corn germ, and corn. Six growing pigs (initial BW, 48.9 +/- 1.99 kg) were placed in metabolism cages and fed diets based on corn, corn and HP DDG, or corn and corn germ. Pigs were allotted to a replicated, 3 x 3 Latin square design. The DE and ME in corn (4,056 and 3,972 kcal/kg of DM, respectively) did not differ from the DE and ME in corn germ (3,979 and 3,866 kcal/kg of DM, respectively). However, HP DDG contained more (P < 0.05) energy (4,763 kcal of DE/kg of DM and 4,476 kcal of ME/kg of DM) than corn or corn germ. Experiment 2 was conducted to measure apparent total tract digestibility (ATTD) and true total tract digestibility of P in HP DDG and corn germ. Thirty growing pigs (initial BW, 33.2 +/- 7.18 kg) were placed in metabolism cages and fed a diet based on HP DDG or corn germ. A P-free diet was used to measure endogenous P losses. Pigs were assigned to treatments in a randomized complete block design, with 10 replications per treatment. The ATTD and the retention of P were calculated for the diets containing HP DDG and corn germ, and the endogenous loss of P was estimated from pigs fed the P-free diet. The ATTD was lower (P < 0.05) in corn germ (28.6%) than in the HP DDG (59.6%). The retention of P was also lower (P < 0.05) in pigs fed corn germ (26.7%) than in pigs fed HP DDG (58.9%). The endogenous loss of P was estimated to be 211 +/- 39 mg per kg of DMI. The true total tract digestibility of P for HP DDG and corn germ was calculated to be 69.3 and 33.7%, respectively. In Exp. 3, apparent ileal digestibility and standardized ileal digestibility values of CP and AA in HP DDG and corn germ were measured using 6 growing pigs (initial BW, 78.2 +/- 11.4 kg) allotted to a replicated, 3 x 3 Latin square design. The apparent ileal digestibility for CP and all AA except Arg and Pro, and the standardized ileal digestibility for CP and all AA except Arg, Lys, Gly, and Pro were greater (P < 0.05) in HP DDG than in corn germ. It was concluded that HP DDG has a greater digestibility of energy, P, and most AA than corn germ.     

Influence of dietary protein level, amino acid supplementation, and dietary energy levels on growing-finishing pig performance and carcass composition

Two experiments were conducted to determine the effects of feeding reduced-CP, AA-supplemented diets at two ambient temperatures (Exp. 1) or three levels of dietary NE (Exp. 2) on pig performance and carcass composition. In Exp. 1, 240 mixed-sex pigs were used to test whether projected differences in heat increment associated with diet composition affect pig performance. There were 10 replications of each treatment with four pigs per pen. For the 28-d trial, average initial and final BW were 28.7 kg and 47.5 kg, respectively. Pigs were maintained in a thermoneutral (23 degrees C) or heat-stressed (33 degrees C) environment and fed a 16% CP diet, a 12% CP diet, or a 12% CP diet supplemented with crystalline Lys, Trp, and Thr (on an as-fed basis). Pigs gained at similar rates when fed the 16% CP diet or the 12% CP diet supplemented with Lys, Trp, and Thr (P > 0.10). Pigs fed the 12% CP, AA-supplemented diet had a gain:feed similar to pigs fed the 16% CP diet when housed in the 23 degrees C environment but had a lower gain:feed in the 33 degrees C environment (diet x temperature, P < 0.01). In Exp. 2, 702 gilts were allotted to six treatments with nine replicates per treatment. Average initial and final BW were 25.3 and 109.7 kg, respectively. Gilts were fed two levels of CP (high CP with minimal crystalline AA supplementation or low CP with supplementation of Lys, Trp, Thr, and Met) and three levels of NE (high, medium, or low) in a 2 x 3 factorial arrangement. A four-phase feeding program was used, with diets containing apparent digestible Lys levels of 0.96, 0.75, 0.60, and 0.48% switched at a pig BW of 41.0, 58.8, and 82.3 kg, respectively. Pigs fed the low-CP, AA-supplemented diets had rates of growth and feed intake similar to pigs fed the high-CP diets. Dietary NE interacted with CP level for gain:feed (P < 0.06). A decrease in dietary NE from the highest NE level decreased gain:feed in pigs fed the high-CP diet; however, gain:feed declined in pigs fed the low-CP, AA-supplemented diet only when dietary NE was decreased to the lowest level. There was a slight reduction in longissimus area in pigs fed the low-CP diets (P < 0.08), but other estimates of carcass muscle did not differ (P > 0.10). These data suggest that pigs fed low-CP, AA-supplemented diets have performance and carcass characteristics similar to pigs fed higher levels of CP and that alterations in dietary NE do not have a discernible effect on pig performance or carcass composition.     

Nutritional value of quality protein maize and food corn for starter and growth pigs

Growth traits with starter and grower pigs and a digestion trial were conducted to compare the nutritional value of Quality Protein Maize (QPM), food corn and conventional feed corn. The QPM, food and feed corn contained .45, .31 and .29% lysine, respectively. The growth trials evaluated a QPM-soybean meal diet formulated on a lysine basis (.96% in starter and .7% in grower diets) and four diets arranged in a 2 (food corn vs feed corn) X 2 (low vs high soybean meal) factorial. Soybean meal was either added in the same amount as in the QPM diet or was added to provide the lysine content of the QPM diet. Performance was similar for pigs fed food corn and feed corn in both trials. The QPM diets resulted in greater performance than food and feed corn diets containing the same level of soybean meal supplementation; starter pigs were more (P less than .10) efficient and grower pigs had a higher (P less than .01) rate and efficiency of gain. However, performance of pigs fed the QPM diets was not equal to that of pigs fed isolysinic food and feed corn diets; growth rate was lower (P less than .05) in starter pigs and gain:feed was lower (P less than .05) in grower pigs. Diets in the digestion trial consisted of the corns plus 3.25% casein. Energy digestibility was similar for all diets. Ileal N and amino acid digestibilities were highest for QPM, intermediate for food corn and lowest for feed corn. In most instances, these differences were significant (P less than .05). Apparent biological value was highest (P less than .05) for QPM. These trials indicate that food corn and feed corn have similar nutritional value, and that starter and grower pigs can benefit from the higher protein quality of QPM.     

Conjugated Linoleic Acid and Dietary Fats Differentially Affect Hepatic ACAT Activity and LDL-Cholesterol in Postweanling Pigs Fed Low-Fat Diets

Two separate studies tested the hypoth-esis that plasma low-density lipoprotein cholesterol (LDL-C) can be decreased by conjugated linoleic acid (CLA) by depressing hepatic acyl-coenzyme A: cholesterol acyltransferase (ACAT) activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di-ets containing either 15% beef tallow, 12% beef tal-low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in-creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol (HDL-C) and very low-density lipoprotein cholesterol (VLDL-C). LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near-ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat-ty acid effects of the high-fat diets on ACAT activity.We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on-ly in pigs fed low-fat diets.