Effect of different dietary protein levels and amino acids supplementation patterns on growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs

Background:This study was conducted to determine the effects of different dietary protein levels and amino acids supplementation patterns in low protein diets on the growth performance,carcass characteristics and nitrogen excretion in growing-finishing pigs.Forty-two barrows(25.00±0.39 kg)were randomly assigned to 7 diets.Diet 1:the high crude protein diet with balanced for 10 essential amino acids(EAAs).Diet 2:the medium crude protein diet with 2%(approx)decreased protein level of Diet 1 and balanced 10 EAAs.Diet 3:the low crude protein diet with 4%decreased protein level of Diet 1 and balanced 10 EAAs.The protein levels of Diet 4,5,6 and 7 were the same as that of Diet 3.Diet 4 was only balanced for lysine(Lys),methionine(Met),threonine(Thr)and tryptophan(Trp);Diet 5 and 6 were further supplemented with extra isoleucine(Ile)or valine(Val),respectively;Diet 7 was further supplemented with extra Ile+Val.Results:Over the 112 days trial,the reduction of dietary protein by 2%or 4%with balanced10 EAAs significantly decreased nitrogen excretion(P<0.05),but had no effects on growth performance and carcass characteristics(P>0.05).In low protein diet,Val supplementation significantly increased body weight gain at 25–50 kg phase(P<0.05),while Ile supplementation at 75–100 kg phase and 100–125 kg phase significantly reduced the ratio of feed to gain(P<0.05).No effect of different dietary protein levels and amino acids supplementation patterns in low protein diets on carcass characteristics was observed(P>0.05).The total N excretion of pigs supplemented with only Lys,Met,Thr and Trp was numerically higher than that of pigs fed with extra Ile,or Val,or Ile+Val diets.Conclusion:In low protein diet,Val is more required than Ile in the early growing phage(25–50 kg),while Ile becomes more required in the late growing and finishing phage(75–125 kg).

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. I and 2 while Exp. 3 used 3.05, 3.1 S, 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 〈 0.0,5） 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.

Effects of long-chain fatty acid supplementation on the growth performance of grower and finisher pigs: a meta-analysis

Background: Supplementation of feed with long-chain fatty acids(LCFAs) during the grower and finisher phases has long been discussed as a growth promotion strategy in pigs, but its effects are inconsistent. The purpose of our study was to comprehensively evaluate its effects on the growth performance based on the average daily gain(ADG), average daily feed intake(ADFI) and gain: feed(G:F) ratio and to unveil the roles of the basal diet, LCFA concentration and LCFA saturation.Results: We searched the Pub Med and Web of Science databases(articles published from Jan 1 st, 2000, to Sep 30 th,2018;restricted to English) and compared LCFA-supplemented diets with control diets. We retrieved 2346 studies, 18 of which(1314 pigs, 26 records) were eligible for our analysis. We used a random-effects model to calculate the weighted mean differences(WMDs) and 95% confidence intervals(CIs). LCFA supplementation in the grower-finisher phase improved the ADG(WMD = 41.74 g/d, 95% CI: 8.81 to 74.66, P = 0.013) and G:F ratio(WMD = 0.019, 95% CI: 0.006 to 0.032, P = 0.003). For supplementation solely in the finisher phase, we found a similar performance in the ADG(WMD = 39.93 g/d, 95% CI: 26.48 to 53.38, P < 0.001) and G:F ratio(WMD = 0.019, 95% CI: 0.006 to 0.032, P < 0.001) but a reduction in the ADFI(WMD =-83.863 g/d, 95% CI:-156.157 to-11.569, P = 0.023). Specifically, approximately 5%LCFA supplementation in the finisher phase had significant effects on the ADG(WMD = 51.385 g/d, 95% CI: 35.816 to66.954, P < 0.001), ADFI(WMD =-102.869 g/d, 95% CI:-189.236 to-16.502, P = 0.02) and G:F ratio(WMD = 0.028, 95%CI: 0.018 to 0.039, P < 0.001), whereas a concentration of approximately 1% exhibited no effects.Conclusions: Overall, regardless of the basal diet and saturation, LCFA supplementation greatly improves the growth performance of grower and finisher pigs, primarily by increasing the energy density.

Effects of Probiotics on Growth, Pork Quality and Serum Metabolites in Growing-finishing Pigs

A total of 72 growing-finishing pigs（56 days old） were used to investigate the effects of dietary probiotics on growing performance, pork quality and serum metabolites. Using single factorial experiment design, pigs were allotted to three groups（four pens/group and six pigs/pen）. Diet treatments were a corn-soybean meal（control group） and a corn-soybean meal with 1% probiotics（probiotics group） or 80 mg kg-1colistin sulfate（antibiotics group）. Pigs were slaughtered when pigs of the lightest averaged 90 kg（157 days of age）. There was no difference（p＆gt;0.05） in average daily gain or feed/gain, and the average daily feed intake of the antibiotics group was higher than that of the probiotics and the control groups（p＆lt;0.05）. Diet supplemented with probiotics reduced the drip loss and cooking loss of pork（p＆lt;0.05）. Dietary supplementation with probiotics significantly decreased the content of triglycerides, lowdensity lipoprotein and urea nitrogen in serum（p＆lt;0.05）, and increased the content of high-density lipoprotein in serum（p＆lt;0.05）. These results suggested improving effects of dietary probiotics on pork quality and serum metabolism in growing-finishing pigs.

Effects of Low Protein Diets Supplemented with Ami-no Acids on Production Performance,Carcass Qual-ity and Input-output Ratio of Pigs

[ Objectives ] To study the effects of low-protein diets supplemented with amino acids on the production performance, carcass quality and input-output ratio of fattening pigs and growing-finishing pigs. [ Methods] Two studies were conducted on fattening pigs and growing pigs respectively. Pigs in two experimental groupswere fed with low-protein diets supplemented with amino acids and normal diets respectively, and the initial weight, final weight, feed consumption and car- cass index of the tested pigs were measured. [ Results] The average final weight of fattening pigs in test group was 2.4 kg lower than that in control group, while the difference was not significant （P 〉 0.05 ）. The average daily gain of fattening pigs in test group was 60 g lower than that in control group, indicating that low protein diets had a tendency to decrease the growth rate （P 〉 0.05 ）, and reduction of daily weight gain in low protein diet pigs reached 7.6%. The development of pigs in low protein diet group was poor, however, the difference was not significant. Carcass backfat thickness in low-protein diet group was slightly higher than that in control group, the difference was significant （ P 〈 0.05 ）. There was no significant difference in input-output ratio between low-protein diet group and control group. Finalweight of growing-finishing pigs in low-protein diet group was 3.22 % lower than that in control group, the average daily weight gainwas 6.91% lower than that in control group, feed intake in test group was 5.48% lower than that in control group, and difference between the two treatments was significant （P 〈 0.05 ）. Feed meat ratio in low-protein diet group improved, however, the difference was not significant（P 〉0.05）. [ Conclusions] Production performance of the pigs would be decreasedand the input-output ratio could not be improvedwhen the adding contents of crude protein in diets was reduced 3% -4%. Therefore, it is recommended that the crude protein level should be enough when pigs were fed with low-protein diets.

青贮果穗玉米对生长育肥猪生长性能和猪肉品质的影响

为研究饲粮中添加青贮果穗玉米对生长育肥猪生长性能、胴体性状及肌肉品质的影响,本试验以192头日龄相近,初始体重为(36.82±1.50) kg的“杜×长×大”商品猪为研究对象,随机分为对照组和试验组(Ⅰ、Ⅱ、Ⅲ),每组4个重复。对照组饲喂基础饲粮,试验组在生长阶段(54 d)分别饲喂含15%、30%和45%青贮果穗玉米的试验饲粮,育肥阶段(62 d)分别饲喂含23%、46%和69%青贮果穗玉米的试验饲粮。结果表明,青贮果穗玉米饲粮对生长育肥猪胴体性状和肌肉品质各项指标无显著影响。对照、试验Ⅲ组全期平均日增重显著低于试验Ⅰ组(P<0.05),其他生长性能指标无显著影响。试验Ⅲ组肌肉亚油酸含量较对照组显著增加36.22%(P<0.05),粗脂肪含量较对照组和试验Ⅰ组显著降低(P<0.05)。综上可知,猪生长、育肥阶段饲粮适宜的青贮果穗玉米含量比例分别为15%~30%和23%~46%,可为其在生长育肥猪上的推广应用提供数据支撑。

葡萄籽原花青素对不同生长阶段猪生长性能的影响

试验旨在研究饲粮中添加葡萄籽原花青素对不同阶段猪生长性能的影响。试验选取48头体重相近的“杜×长×大”三元杂交猪,随机分为4组,每组3个重复,每个重复4头猪。试验分3个生长阶段进行,对照组始终饲喂基础饲粮,试验组在第Ⅰ阶段(断奶仔猪阶段)的基础饲粮中分别添加50、100、150 mg/kg的GSPs,第Ⅱ阶段(生长猪阶段)分别添加100、150、200 mg/kg的GSPs,第Ⅲ阶段(育肥猪)分别添加150、200、250 mg/kg的GSPs进行饲喂。结果发现,在断奶仔猪阶段,饲料中添加100 mg/kg的GSPs显著提高了ADG和ADFI(P<0.05);在生长猪阶段,饲料中添加150 mg/kg的GSPs显著提高了ADG和ADFI,显著降低了F/G(P<0.05);在育肥猪阶段添加GSPs没有显著的促进作用,添加250 mg/kg的GSPs反而降低了育肥猪的生长性能。试验表明不同生长阶段猪饲料中添加适量的GSPs对断奶仔猪和生长猪的生长性能有一定的促进作用。

基于荟萃分析评估生长育肥猪能量与蛋白质摄入及预测其生长性能

采用荟萃分析方法,通过整合2002—2022年共112篇文献的研究结果,拟合多项式函数、幂函数与Bridges函数3种函数模型来预测中国生长育肥猪的每日消化能摄入量与粗蛋白摄入量,并预测猪的体质量、饲粮消化能摄入量、饲粮粗蛋白摄入量与生长性能指标之间的函数关系。结果表明:3种函数模型均对消化能摄入量、粗蛋白摄入量进行了合理拟合,其中,多项式函数较幂函数与Bridges函数的拟合优度更高。多项式函数与Bridges函数对消化能摄入量的预测值整体上高于美国国家科学研究委员会(National Research Council, NRC)于2012年发布的《猪营养需要》[以下简称NRC(2012)]提供的数值;3种函数对粗蛋白摄入量的预测值整体上低于或接近于NRC(2012)提供的数值。本研究结果有助于制定更符合生长育肥猪营养需要的饲喂计划,为生猪饲料配制提供参考,从而提高饲料利用率、降低生猪饲养成本。

栀子粉对生长育肥猪生长性能、肉品质、抗氧化能力及经济效益的影响

本试验旨在研究饲粮中添加不同水平的栀子粉对生长育肥猪生长性能、胴体性状、肉品质、抗氧化能力及经济效益的影响。选取初始体重为(34.71±3.49)kg的健康生长育肥猪(杜×长×大)144头,随机分为4个组,每组6个重复,每个重复6头猪(公母各占1/2)。对照组饲喂未添加栀子粉的基础饲粮,其余3组分别饲喂添加0.4%、0.8%、1.2%栀子粉的试验饲粮,试验期96 d。结果表明:1)随着栀子粉添加水平的增加,生长育肥猪的末重呈线性和二次增加(P<0.05),平均日增重(ADG)呈线性增加(P<0.05),料重比(F/G)呈线性降低(P<0.05)。与对照组相比,0.4%、0.8%和1.2%栀子粉组试验猪的末重、ADG均显著提高(P<0.05),0.8%和1.2%栀子粉组试验猪的F/G显著降低(P<0.05)。2)各组之间胴体性状指标无显著差异(P>0.05)。3)随着栀子粉添加水平的增加,生长育肥猪背最长肌的24 h pH、45 min亮度值和黄度值呈线性升高(P<0.05),24 h滴水损失、48 h红度值和剪切力均呈线性降低(P<0.05)。与对照组相比,1.2%栀子粉组试验猪背最长肌的45 min黄度值显著提高(P<0.05),0.4%、0.8%和1.2%栀子粉组试验猪背最长肌的剪切力显著降低(P<0.05)。4)生长育肥猪的血浆总抗氧化能力(T-AOC)随栀子粉添加水平的增加呈线性升高(P<0.05),且0.4%和1.2%栀子粉组血浆T-AOC显著高于对照组(P<0.05)。肝脏T-AOC和还原型谷胱甘肽(GSH)含量随栀子粉添加水平增加呈线性升高(P<0.05)。肌肉T-AOC和总超氧化物歧化酶(T-SOD)活性随栀子粉添加水平的增加呈线性升高(P<0.05),且0.8%和1.2%栀子粉组肌肉T-AOC显著高于对照组(P<0.05)。5)与对照组相比,0.4%、0.8%、1.2%栀子粉组的毛利润分别提高了67.08、77.61和70.44元/头,其中0.8%栀子粉组的增重成本最低,毛利润最高。由此可见,饲粮中添加0.8%栀子粉能改善生长育肥猪的生长性能,提高经济效益,增强抗氧化能力,降低猪肉剪切力,且对肉色无不利影响。

低蛋白、低豆粕日粮中添加复合酶对生长猪生产性能及经济效益的影响

该试验旨在研究采用非常规饲料原料替代豆粕制成的低蛋白、低豆粕日粮对生长猪生产性能及经济效益的影响。试验选用36 kg左右的健康杜长大三元杂生长猪360头,随机分成4组,每组6个重复,每个重复15头猪,对照组A饲喂正常蛋白水平的高豆粕日粮(CP17.0),试验组B饲喂低蛋白水平的高豆粕日粮(CP15.0),试验组C饲喂低蛋白水平的低豆粕日粮(CP15.0),试验组D饲喂低蛋白水平的低豆粕+复合酶制剂日粮(CP15.0),试验期为30天。试验结果表明:低蛋白低豆粕日粮,不影响生长猪的平均日增重、平均日采食量、料重比(P>0.05)。每千克体重增重成本以低蛋白低豆粕+复合酶的试验D组最佳,比正常日粮对照组A低0.49元/千克。

不同圆环病毒2型疫苗对生长育肥猪影响的研究

为评估不同圆环病毒2型疫苗对生猪生长肥育期免疫效果,本试验选择国产和进口两种疫苗,对同一批23日龄断奶长大二元杂交去势仔猪360头,随机分成A、B、C三组,每组120头,A组免疫国产SEPPIC佐剂PCV2a全病毒灭活疫苗(WH株)、B组免疫进口水质佐剂亚单位疫苗(PCV2a Cap蛋白),C组不做任何处理。结果显示,与国产圆环病毒2型疫苗相比,进口疫苗在生长性能、抗体水平及免疫保护期等方面均表现出了较强的优势,经济效益较为显著。

发酵乳酸杆菌对生长肥育猪生长性能和肉品质的影响

本试验旨在研究日粮中添加发酵乳酸杆菌(Lactobacillus fermentum)对生长肥育猪生长性能和肉品质的影响。试验选择144头日龄、胎次相近,体重在20 kg左右的杜×长×大三元仔猪,公母各占1/2,随机分成对照组、抗生素组和发酵乳酸杆菌组,每组6个重复,每个重复8头猪。试验分2个阶段:生长阶段(体重20～50 kg)和肥育阶段(体重50～90 kg)。对照组饲喂基础日粮,抗生素组饲喂基础日粮+150 mg/kg金霉素,发酵乳酸杆菌组饲喂基础日粮+0.1%发酵乳酸杆菌。结果表明:(1)生长性能方面,在生长阶段,发酵乳酸杆菌组的平均日增重(ADG)比对照组提高了5.8%,料重比(F/G)降低了2.7%;在肥育阶段,发酵乳酸杆菌组的ADG比对照组提高了6.7%,F/G降低了4.6%;在整个试验期,发酵乳酸杆菌组的ADG比对照组提高了6.3%,F/G降低了3.9%。日粮中添加0.1%单一的发酵乳酸杆菌代替抗生素(金霉素),试验猪生长性能略优于抗生素(P>0.05)。在生长阶段,发酵乳酸杆菌组的ADG比抗生素组提高了0.1%,F/G降低了2.3%;在肥育阶段,发酵乳酸杆菌组的ADG比抗生素组提高了9.2%,F/G降低了3.7%;在整个试验期,发酵乳酸杆菌组的ADG比抗生素组提高了5.1%,F/G降低了2.5%;(2)发酵乳酸杆菌组滴水损失比对照组和抗生素组分别降低2.3%和5.0%,剪切力比对照组和抗生素组分别降低26.1%和18.2%;(3)与对照组相比,发酵乳酸杆菌组显著提高了C18∶2、C20∶2、C20∶4和总多不饱和脂肪酸(PUFA)的含量(P<0.05);与抗生素组相比,显著降低了C20∶2的含量(P<0.05)。以上研究结果表明,发酵乳酸杆菌能不同程度地改善生长肥育猪生长性能、胴体品质和肌肉质量。

苜蓿草粉对生长猪生产性能及血清指标的影响

选取体重约25 kg的长×大二元杂交猪60头,采用单因子完全随机设计,分为5组,3个重复,在饲粮中添加不同比例的苜蓿草粉。在正试期开始后的第1、20和40天称试验猪的体重,分析其饲喂含苜蓿草粉饲粮后的主要生产性能。在正试期开始后的第20天采取猪的血样,分析其饲喂苜蓿后血液中主要生化指标。结果表明:(1)添加5%,10%苜蓿草粉有利于提高生长猪的增重及饲料转化率,尤其10%组的日增重、日采食量较对照组有极显著改善,饲料转化效率较对照组明显提高。而15%、20%的苜蓿草粉组的上述指标比对照组降低。(2)添加苜蓿草粉后,饲粮干物质、粗蛋白质、NDF的消化率提高。(3)添加苜蓿草粉后,GH、Ins和IGF-1的含量显著提高,但试验组中的T3、T4含量显著降低;随着苜蓿草粉添加水平的提高,血液中尿素氮、甘油三酯、血糖和胆固醇含量递减,其中试验II组胆固醇含量和对照组相比差异显著,试验III、IV组与对照组相比差异极显著。而总蛋白的含量随草粉添加量上升有所提高,尽管各组间无显著性差异。上述结果表明:在生长猪饲粮中添加10%紫花苜蓿草粉后对生长猪生产性能、营养消化率及血液生化指标有较显著的改善。结合生产实际,建议在生长猪饲粮中添加10%紫花苜蓿草粉。

饲粮添加高铜和VE对猪生长性能和猪肉品质的影响

用 36头约克猪研究了在 2 0～ 10 0kg饲粮中添加高铜和VE对猪生产性能和猪肉品质的影响。试验采用 2×2因子设计 ,在对照饲粮中添加 2 5 0mg/kg铜或 /和 2 0 0mg/kgVE。结果表明 ,单独添加高铜或VE或二者同时添加有提高ADG、降低F/G的趋势 ,二者同时添加显著降低全期F/G(P <0 0 5 )。单独添加高铜趋于提高眼肌面积 ,不影响屠宰性能和肌肉养分含量 ,对冷存肉 (4℃贮存 )的滴水损失、硫代巴比妥酸反应物 (TBA)值和肉色无明显影响 (P >0 0 5 )。单独添加VE有提高眼肌面积和鲜肉肉色评分、降低鲜肉滴水损失和失水率的趋势 (P >0 0 5 ) ,提高鲜肉Fe、Cu和VE的含量 (P <0 0 5 ) ,降低冷存 9天猪肉的TBA值 (P <0 0 1)和滴水损失 (P >0 0 5 ) ,稳定冷存猪肉的肉色达 6～ 9d(P <0 0 5 )。同时添加高铜和VE的作用规律与单独添加VE时相同 ,但作用程度略低于后者。本研究表明 ,在生长育肥猪饲粮中添加 2 5 0mg铜 /kg对猪肉品质无不良影响 ,而添加 2 0 0mgVE/kg可改善猪肉品质 。

中草药替代抗生素对育肥猪生产性能和免疫功能的影响

为探索在生长育肥猪日粮中添加中草药饲料添加剂替代抗生素的可行性及最佳用量,选取15kg左右的杜×长×大三元杂交猪120头,进行了在基础日粮中添加0.1%、0.2%、0.4%的中草药饲料添加剂替代抗生素的饲养试验。结果表明,以添加0.2%的中草药饲料添加剂的效果最好,与抗生素组相比,日增重提高1.45%,料重比降低0.41%,但差异均不显著(P>0.05);猪血清中免疫球蛋白IgGI、gM、IgA含量分别提高20.55%、16.78%、13.69%,补体C3、C4含量分别提高15.56%、15.60%,差异显著(P<0.05)。结论,添加0.2%的中草药饲料添加剂能促进猪的生长,增强其免疫功能。

发酵桑叶对生长育肥猪生长性能、胴体品质和肌肉营养成分的影响

本试验旨在研究饲粮中添加发酵桑叶对生长育肥猪生长性能、胴体品质和肌肉营养成分的影响。试验选择日龄相近、体重为(35.00±4.32)kg的健康“杜×长×大”商品猪96头,随机分为4组,每组4个重复,每个重复6头猪。对照组饲喂玉米-豆粕型基础饲粮,试验Ⅰ、Ⅱ、Ⅲ组在生长阶段(35~70 kg)分别饲喂在基础饲粮中添加4%、8%和12%发酵桑叶的饲粮,育肥阶段(71~130 kg)分别饲喂在基础饲粮中添加12%、15%和18%发酵桑叶的饲粮。试验Ⅰ、Ⅱ、Ⅲ组生长阶段和育肥阶段发酵桑叶替代豆粕的比例分别为1.0%、2.0%、3.0%和3.0%、3.8%、4.5%。试验期为128 d(生长阶段50 d,育肥阶段78 d)。结果表明:1)与对照组相比,生长阶段饲粮中添加4%、8%发酵桑叶对试验猪平均日增重(ADG)和料重比(F/G)无显著影响(P>0.05),当添加量达到12%时,ADG极显著降低(P<0.01);育肥阶段饲粮中添加12%发酵桑叶对ADG和F/G无显著影响(P>0.05),当添加量达到15%和18%时,ADG极显著降低(P<0.01);生长和育肥阶段饲粮中分别添加4%和12%发酵桑叶对试验全期ADG和F/G无显著影响(P>0.05),当添加量分别达到8%、15%和12%、18%时,ADG均极显著降低(P<0.01)。2)与对照组相比,饲粮添加发酵桑叶对生长育肥猪胴体品质以及肌肉中粗脂肪、粗蛋白质、氨基酸和核苷酸含量均无显著影响(P>0.05),生长阶段添加4%、育肥阶段添加12%发酵桑叶时肌肉中次黄嘌呤核苷酸含量有所增加(P>0.05);饲粮中添加8%(生长阶段)和15%(育肥阶段)发酵桑叶时,肌肉中总脂肪酸、饱和脂肪酸和单不饱和脂肪酸含量有所降低(P>0.05)。综上所述,猪生长和育肥阶段饲粮中发酵桑叶的添加量分别以4%和12%为宜。

凹凸棒石黏土对生长育肥猪生产性能、金属含量及肉品质的影响

研究凹土原土及热改性凹土对生长育肥猪生产性能、金属含量和肉品质的影响。选用体重约47kg健康'杜×长×大'三元杂交的生长育肥猪60头,随机分为3组,每组4个重复。对照组饲喂基础日粮,试验组饲喂在基础日粮中添加2%凹土原土、2%热改性凹土的试验日粮。结果表明:1)凹土原土和热改性凹土对生长育肥猪生产性能无显著影响(P>0.05);2)凹土原土和热改性凹土降低血液中As、Pb、Cr含量和腿肌中Cr的含量(P<0.05),热改性凹土显著提高血液中Mg含量(P<0.05);3)凹土原土降低眼肌MDA(P<0.05),凹土原土和热改性凹土降低眼肌中T-AOC的活性(P<0.05);4)凹土原土提高眼肌p H45 min、a*45 min(P<0.05),降低L*45 min、b*24 h和压力损失(P<0.05)。添加凹土原土和热改性凹土能降低重金属在动物机体中的沉积、提高抗氧化能力进而改善肉品质,热改性凹土效果优于原土。

不同饲养方案对猪生产性能及猪肉品质的影响

研究了不同饲养方案对猪生产性能和猪肉品质的影响。试验共分 4个处理 :处理 1,对照 ,按常规饲养标准饲养 ;处理 2 ,按组装新方案饲养 (生长期添加 2 0 0 μg/kg的酵母铬 ,肥育期添加 2 0 0mg/kgVE ,且肥育期饲粮能量浓度在对照组基础上降低 0 4Mcal/kg、蛋白质降低 2 % ) ;处理 3,90 %对照饲粮 +10 % (按风干基础计 )青饲料 ;处理 4 ,90 %新方案饲粮 +10 % (按风干基础计 )青饲料。每个处理 5个重复 ,每个重复 1头猪。 2 0头 2 0kg左右的长白×约克杂交生长猪 ,按体重大小随机分配到各个处理组中。试验至 10 0kg左右体重结束。猪自由饮水和采食。结果表明 :①饲喂适量青饲料能显著降低猪的背膘厚和提高瘦肉率 (P <0 0 5 )。按风干基础计 ,用青饲料替代 10 %基础饲粮 ,使背膘厚降低 2 0 0 %～ 2 3 0 %、瘦肉率提高 4 0 %～ 4 5 % ;②饲喂适量青饲料有降低猪肉滴水损失和提高肉品风味的作用 ,背最长肌中次黄嘌呤核苷含量提高 6 0 %～ 8 0 % ;③生长期补充 2 0 0 μg/kg的酵母铬对生产性能无影响 ,有改善眼肌面积和瘦肉率的趋势 ,对其它屠宰性能指标和肉质参数无影响 ;④肥育期添加 2 0 0mg/kg的VE对肉色、pH值及滴水损失等肉质指标无影响 ;

挤压膨化加工对菜籽粕中抗营养因子含量及膨化菜籽粕对生长育肥猪生长性能的影响

本试验旨在研究挤压膨化加工对菜籽粕(RM)中抗营养因子、营养物质含量以及膨化菜籽粕(ERM)对生长育肥猪生长性能、营养物质表观消化率的影响。试验1:采用本实验室的TSE65双螺杆干法挤压膨化机和优化后的加工参数组合对饲料级RM进行挤压膨化加工,测定RM和ERM中的抗营养因子和营养物质含量。试验2:以RM和ERM为主要试验材料,选取72头体重为(33.82±3.72)kg的杜×长×大三元杂交猪,随机分成6组,每个组3个重复,每个重复4头猪。试验16周,1、3、5组分别饲喂添加6%、10%和14%RM的饲粮,试验2、4、6组分别饲喂添加6%、10%和14%ERM的饲粮;试验712周,1、3、5组分别饲喂添加10%、14%和18%RM的饲粮,试验2、4、6组分别饲喂添加10%、14%和18%ERM的饲粮。试验期为12周。结果表明:1)与RM相比,ERM中干物质、粗蛋白质、粗脂肪、粗灰分、钙和总磷含量都有所增加;ERM中粗脂肪和干物质含量显著升高(P<0.05),半胱氨酸、赖氨酸和精氨酸含量显著降低(P<0.05),总氨基酸含量下降了1.75%(P>0.05),硫苷和植酸含量显著降低(P<0.05),异硫氰酸酯和唑烷硫酮含量低于检测限0.15 mg/g,单宁含量无显著变化(P>0.05)。2)16周内,同等添加量下,2、4组末重(FBW)显著高于1、3组(P<0.05);4组平均日采食量(ADFI)显著高于其余各组(P<0.05);各组间平均日增重(ADG)和料重比(F/G)均无显著差异(P>0.05);6组粗蛋白质、粗脂肪和干物质表观消化率显著高于5组(P<0.05);6组除蛋氨酸、丝氨酸和谷氨酸表观消化率与5组差异不显著(P>0.05)外,其余氨基酸表观消化率均显著高于5组(P<0.05)。712周内,同等添加量下,2、4组FBW高于1、3组,6组FBW低于5组,但差异均不显著(P>0.05);2组粗蛋白质、粗脂肪和干物质表观消化率显著高于1组(P<0.05);2组缬氨酸、异亮氨酸、赖氨酸、组氨酸、苏氨酸、天冬氨酸、酪氨酸、谷氨酸、甘氨酸、半胱氨酸、脯氨酸和总氨基酸表观消化率显著高于1组(P<0.05)。由此可见,挤压膨化加工能提高RM的营养价值并降低多种抗营养因子含量,在育肥猪饲粮中添加ERM可以提高育肥猪的生长性能和营养物质表观消化率。30-60 kg的育肥猪饲粮中ERM适宜添加量为10%,61120 kg的育肥猪饲粮中ERM适宜添加量为14%。

棉籽粕膨化前后品质变化及对生长育肥猪生长性能、血清生化指标及营养物质表观消化率的影响

本试验旨在研究湿法挤压膨化加工对棉籽粕中营养物质、游离棉酚含量的影响,以及膨化棉籽粕对生长育肥猪生长性能、血清生化指标及营养物质表观消化率的影响。首先,采用牧羊56×2挤压膨化机和前期优化后的加工参数组合对棉籽粕进行膨化,对比测定棉籽粕和膨化棉籽粕的营养物质和游离棉酚含量的变化。然后,以棉籽粕和膨化棉籽粕为主要试验材料,选取80头体重为(28.78±3.09)kg的杜×长×大三元杂交猪为试验动物,随机分为5个组,每组4个重复,每个重复4头猪(公母各占1/2)。对照组饲喂全玉米-豆粕型基础饲粮,试验1组饲喂添加普通棉籽粕(生长期添加5%普通棉籽粕,育肥期添加10%普通棉籽粕)的饲粮,试验2组、试验3组、试验4组分别饲喂添加膨化棉籽粕(生长期分别添加5%、10%和15%膨化棉籽粕,育肥期分别添加10%、15%和20%膨化棉籽粕)的饲粮,各组饲粮中代谢能和粗蛋白质等营养水平均调配均衡。试验期13周(生长期6周,育肥期7周)。结果表明:1)挤压膨化处理对棉籽粕营养物质含量无明显影响,膨化棉籽粕总氨基酸含量和各个必需氨基酸含量略有升高,游离棉酚含量降低了87.85%。2)生长期,饲粮中添加5%膨化棉籽粕与相同含量的普通棉籽粕相比可提高生长猪的平均日采食量和平均日增重(P>0.05),显著降低料重比(P<0.05),并显著提高粗蛋白质、干物质、粗脂肪和部分氨基酸表观消化率(P<0.05);饲粮中添加膨化棉籽粕比起添加棉籽粕可显著降低生长猪血清中丙二醛(MDA)含量(P<0.05),显著提高生长猪的总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性和谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05);饲粮中添加膨化棉籽粕比起添加棉籽粕有提高生长猪血清中免疫球蛋白、三碘甲腺原氨酸和四碘甲腺原氨酸的趋势;随着膨化棉籽粕添加量的增加,生长猪的生长性能和营养物质表观消化率均呈现降低趋势,当添加量达15%时与普通棉籽粕组相比无显著差异(P>0.05)。3)育肥期,各膨化棉籽粕组末均重、平均日增重和平均日采食量与对照组和普通棉籽粕组相比差异不显著(P>0.05),但全期试验2组和试验3组料重比显著低于试验1组(P<0.05);饲粮中添加膨化棉籽粕比起添加棉籽粕还可以显著提高育肥猪的抗氧化能力和免疫能力(P<0.05),且随着膨化棉籽粕添加量的增加,育肥猪血清中MDA含量显著降低(P<0.05),T-AOC、SOD活性和GSH-Px活性显著升高(P<0.05)。试验组粗蛋白质表观消化率和干物质表观消化率均显著低于对照组(P<0.05),各膨化棉籽粕组粗蛋白质表观消化率与试验1组差异不显著(P>0.05),各膨化棉籽粕组干物质表观消化率均显著高于试验1组(P<0.05);试验3组和试验4组粗脂肪表观消化率显著高于对照组和试验1组(P<0.05),且随着膨化棉籽粕添加量的增加,粗脂肪表观消化率逐渐升高。饲粮中添加适量的膨化棉籽粕比起添加棉籽粕可显著提高氨基酸表观消化率(P<0.05)。由此可见,挤压膨化加工对棉籽粕营养物质含量影响较小,且能显著降低游离棉酚的含量,在生长育肥猪饲粮中添加膨化棉籽粕可以显著提高生长育肥猪的生长性能、抗氧化能力、免疫能力和营养物质表观消化率,生长猪饲粮中添加量可达15%,育肥猪饲粮中添加量可达20%。