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 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 dietary protein restriction on muscle fiber characteristics and m TORC1 pathway in the skeletal muscle of growing-finishing pigs

Background： To investigate the effects of dietary crude protein（CP） restriction on muscle fiber characteristics and key regulators related to protein deposition in skeletal muscle, a total of 18 growing-finishing pigs（62.30 ± 0.88 kg）were allotted to 3 groups and fed with the recommended adequate protein（AP, 16 % CP） diet, moderately restricted protein（MP, 13 % CP） diet and low protein（LP, 10 % CP） diet, respectively. The skeletal muscle of different locations in pigs, including longissimus dorsi muscle（LDM）, psoas major muscle（PMM） and biceps femoris muscle（BFM） were collected and analyzed.Results： Results showed that growing-finishing pigs fed the MP or AP diet improved（P 〈 0.01） the average daily gain and feed： gain ratio compared with those fed the LP diet, and the MP diet tended to increase（P = 0.09） the weight of LDM. Moreover, the ATP content and energy charge value were varied among muscle samples from different locations of pigs fed the reduced protein diets. We also observed that pigs fed the MP diet up-regulated（P 〈 0.05） muscular m RNA expression of all the selected key genes, except that myosin heavy chain（My HC） IIb,My HC IIx, while m RNA expression of ubiquitin ligases genes was not affected by dietary CP level. Additionally, the activation of mammalian target of rapamycin complex 1（m TORC1） pathway was stimulated（P 〈 0.05） in skeletal muscle of the pigs fed the MP or AP diet compared with those fed the LP diet.Conclusion： The results suggest that the pigs fed the MP diet could catch up to the growth performance and the LDM weight of the pigs fed the AP diet, and the underlying mechanism may be partly due to the alteration in energy status, modulation of muscle fiber characteristics and m TORC1 activation as well as its downstream effectors in skeletal muscle of different locations in growing-finishing 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. 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.

Feeding Effect of Growing-Finishing Pigs under Fine Division of Feeding Stages

In order to study the feeding effect of fine division of feeding stages on the growing-finishing pigs,96 healthy Duroc × Landrace ×Yorkshire hybrid commercial pigs with similar age in days,size,and body weight about 15 kg,half boars and half sows,randomly divided into3 treatments( each treatment repeated 4 times,and each repetition 8 pigs). According to the body weight division standard,three stages,four stages,and five stages of feeding were adopted separately. The daily ration of with different nutrition levels was used,body weight and feed consumption were measured,and effects of different feeding methods on body weight increase,feed utilization,and economic benefits of growing-finishing pigs. The results showed that compared with the three-stage feeding,the body weight of five-stage and four-stage feeding increased by 4. 18%( P < 0. 01) and 2. 41%( P < 0. 05),respectively,and the body weight of five-stage feeding increased by 1. 74%( P < 0. 05) compared with that of four-stage feeding; the daily feed consumption of five-stage and four-stage feeding increased 3. 10%( P < 0. 01) and 1. 70%(P <0. 01),respectively,and the daily feed consumption of five-stage feeding was 1. 37% higher than that of four-stage feeding. The feed cost of five-stage feeding and four-stage feeding increased 3. 32%( P < 0. 01) and 1. 61%( P < 0. 05) separately,and the feed cost of five-stage feeding was 1. 69% higher than that of four-stage feeding( P < 0. 01). The income from average body weight increase of five-stage and fourstage feeding increased by 5. 47%( P < 0. 01) and 3. 59%( P < 0. 01) respectively,and the benefit of average body weight increase of fivestage feeding was 1. 81% higher than that of four-stage feeding( P > 0. 05). The crude protein consumption from average body weight increase of five-stage and four-stage feeding decreased by 2. 28%( P < 0. 01) and 1. 68%( P < 0. 01),respectively; the crude protein consumption from average body weight increase of five-stage feeding was 0. 67% lower than that of four-stage feeding; the feed conversion ratio of five-stage feeding,four-stage feeding,and three-stage feeding was 2. 92,2. 93,and 2. 95 respectively. The results showed that compared with the threestage feeding,the four-stage and five-stage feeding could significantly increase the body weight of the growing-finishing pigs,improve the feed utilization level and improve the economic benefits,and the effect of five-stage feeding was better than the four-stage feeding.

Dietary supplementation of Lonicera macranthoides leaf powder improves amino acid profiles in serum and longissimus thoracis muscle of growing-finishing pigs

A 60-days feeding trial was conducted to determine the effect of dietary supplementation of Lonicera macranthoides leaf(LML) on growth performance, meat quality, and free amino acid profiles in growingfinishing pigs. L. macranthoides leaves were harvested, air-dried and milled to powder. A total of 288 crossbred barrows(Large White x Landrace) with an average initial BW of 54.0 ± 3.4 kg were randomly allocated to 3 treatment groups and fed either a basal diet or a diet supplemented with 0.5% or 1.0% LML powder. Results showed that diet supplemented with LML powder did not affect average daily feed intake(ADFI) and feed: gain ratio(P> 0.05) in growing-finishing pigs. Moreover, diet supplemented with LML powder showed no significant effects on carcass traits(P > 0.05) including dressing percentage,backfat thickness and loin muscle area, and meat quality traits(P > 0.05) including meat color, intramuscular fat and cooking loss. However, diet supplemented with LML powder significantly improved free amino acid profiles in serum and longissimus thoracis muscle in growing-finishing pigs. Most importantly, dietary LML powder increased total free amino acids content(P < 0.001) and essential free amino acid content(P < 0.001) in longissimus thoracis muscle. These results indicate that LML has the potential to improve the nutritional value of meat through improving free amino acid profiles.

某猪场致生长育肥猪腹泻的猪圆环病毒2型(PCV-2)病原学检测与病理组织学观察

某猪场80日龄左右的生长育肥猪群出现顽固性腹泻,腹泻粪便的形状复杂,为了查明病原,该试验采集病猪病料,提取病毒DNA和RT-PCR检测,并进行病理变化分析和病理组织学观察。结果表明:实时荧光定量PCR检测显示猪圆环病毒2型(PCV-2)强阳性,剖检发现脾脏有轻微梗死、淋巴结萎缩,病理组织学观察发现回肠肠粘膜上皮细胞显著增生,由单层变为多层,淋巴结和脾脏的淋巴细胞数量显著减少。试验说明PCV2是引起该猪场育肥猪腹泻的主要病原。

添加植物油降低饲粮n-6/n-3多不饱和脂肪酸比值对生长肥育猪脂肪沉积和脂肪酸组成及脂代谢相关基因表达的影响

本试验旨在研究饲粮添加植物油降低n-6/n-3多不饱和脂肪酸(PUFA)比值对生长肥育猪脂肪沉积和脂肪酸组成及脂代谢相关基因表达的影响。试验选用54头体重[(45.30±1.72)kg]相近的“杜×长×大”三元杂交猪,随机分为3组,每组6个重复,每个重复3头。对照组饲喂基础饲粮,试验组分别饲喂含4.5%菜籽油(菜籽油组)和4.5%混合油(混合油组,菜籽油∶亚麻籽油=1∶1)的饲粮。3组饲粮粗脂肪含量分别为2.76%、7.24%和7.24%,n-6/n-3 PUFA比值分别约为10∶1、4∶1和2∶1,消化能和粗蛋白质含量基本相同。预试期7 d,正试期42 d。结果表明:1)与对照组相比,饲粮添加植物油显著提高生长肥育猪背最长肌肌内脂肪(IMF)含量(P<0.05),对平均日增重(ADG)、平均日采食量(ADFI)、料重比(F/G)及背膘厚无显著影响(P>0.05)。2)与对照组相比,饲粮添加植物油显著提高背最长肌和皮下脂肪n-3及总PUFA含量(P<0.05),降低n-6/n-3 PUFA比值(P<0.05);与菜籽油组相比,混合油组背最长肌和皮下脂肪n-3 PUFA含量显著提高(P<0.05),n-6/n-3 PUFA比值显著降低(P<0.05)。3)与对照组相比,饲粮添加植物油显著提高背最长肌和皮下脂肪组织脂肪酸转位酶/CD36(FAT/CD36)和脂肪酸转运蛋白1(FATP1)mRNA相对表达量(P<0.05),且混合油组背最长肌FAT/CD36和脂肪酸转运蛋白4(FATP4)mRNA相对表达量显著高于菜籽油组(P<0.05)。4)与对照组相比,饲粮添加植物油显著提高背最长肌碳水化合物反应元件结合蛋白(ChREBP)、葡萄糖转运子4(Glut4)及脂肪酸合酶(FAS)、乙酰辅酶A羧化酶(ACC)、脂肪酸延伸酶5(Elovl5)和脂肪酸延伸酶6(Elovl6)等生脂基因mRNA相对表达量(P<0.05),显著降低皮下脂肪组织过氧化物酶体增殖物激活受体γ(PPARγ)、维甲酸X受体α(RXRα)及生脂基因mRNA相对表达量(P<0.05)。综上所述,添加植物油降低饲粮n-6/n-3 PUFA比值可上调FAT/CD36和FATP1表达,促进猪肌肉和皮下脂肪组织吸收和利用饲粮长链脂肪酸合成脂肪;下调PPARγ及生脂基因表达,抑制皮下脂肪组织从头脂肪合成,而上调ChREBP及生脂基因表达,促进背最长肌脂肪合成,提高IMF含量,且饲粮n-6/n-3 PUFA比值为2∶1时能更有效地改善组织n-3 PUFA含量和n-6/n-3 PUFA比值。

生长育肥猪菜籽饼消化能和代谢能的测定及预测模型的建立

本试验测定了不同来源的10个菜籽饼的化学成分以及生长育肥猪消化能(DE)和代谢能(ME),并基于其有效化学成分含量构建DE和ME预测方程。选取健康的、初始体重为(51.2±1.7)kg的杂交[杜×(长×大)]阉公猪22头,采用2个不完全的11×3拉丁方设计,分别饲喂10个菜籽饼饲粮和1个基础饲粮,菜籽饼饲粮以菜籽饼替代基础饲粮的20%,试验共3个周期,每个周期包括7 d预试期和5 d粪尿收集期,采用全收粪、尿法和套算法测定生长育肥猪对菜籽饼的DE和ME。结果显示:1)在饲喂基础上,10个菜籽饼的干物质(DM)含量为87.95%~94.68%,总能(GE)为18.45~20.84 MJ/kg,粗蛋白质(CP)、粗脂肪(EE)、粗灰分(Ash)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、钙(Ca)、总磷(TP)和总硫苷(TGS)含量分别为35.15%~43.61%、5.48%~11.76%、5.99%~7.75%、8.26%~11.32%、21.89%~48.61%、13.13%~22.87%、0.50%~0.62%、0.92%~1.30%和20.25~25.02μmol/g,其中EE、CF、NDF、ADF和TGS含量的变异系数均超过了10%。2)在饲喂基础上,10个菜籽饼的DE和ME平均值分别为13.49和12.43 MJ/kg。3)菜籽饼NDF含量与DE、ME均呈极显著负相关(P<0.01),DE和ME的最佳预测方程分别为DE=15.398-0.063×NDF[剩余标准差(RSD)=0.134,决定系数(R 2)=0.954,P<0.01]和ME=14.690-0.075×NDF(RSD=0.141,R 2=0.963,P<0.01)。综上可知,不同来源菜籽饼的纤维组分的变异性较大,NDF含量是菜籽饼生长育肥猪DE与ME的最佳预测因子。

生长育肥猪小麦消化能和代谢能的测定及预测模型的建立

本试验旨在测定小麦用于饲喂生长肥育猪的消化能(DE)和代谢能(ME),并基于小麦有效化学成分含量构建DE和ME的预测模型。选取健康、体重为(50.0±1.7)kg的“杜×长×大”阉公猪22头,采取有重复的11×3不完全拉丁方设计,分别饲喂10个小麦饲粮和1个基础饲粮,试验共3个周期,每期12 d(7 d预饲+5 d粪尿收集),采用全收粪、尿法和套算法测定生长育肥猪对小麦的DE和ME。结果显示:1)在饲喂基础上,10个小麦的干物质(DM)、粗蛋白质(CP)、粗脂肪(EE)、总淀粉(TS)、粗灰分(Ash)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、钙(Ca)、木聚糖(Xylan)和总磷(TP)含量及总能(GE)的平均值分别为87.40%、13.34%、1.94%、55.19%、1.83%、1.56%、14.78%、3.05%、0.05%、6.44%、0.31%和15.48 MJ/kg。2)在饲喂基础上,10个小麦DE和ME的平均值分别为13.85和13.32 MJ/kg。3)小麦NDF含量与DE、ME均呈显著负相关(P<0.05),DE和ME的最佳预测方程为:DE(MJ/kg)=17.783-0.266NDF(%)[剩余标准差(RSD)=0.375,决定系数(R2)=0.60,P<0.01];ME(MJ/kg)=19.453-0.415NDF(%)(RSD=0.400,R2=0.76,P<0.01)。综上可知,不同来源小麦的化学组成变异性较大,NDF含量是生长育肥猪小麦DE与ME的最佳预测因子。

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。

富硒五谷虫粉对生长育肥猪生长性能、血清生化指标、屠宰性能和肉品质的影响

试验探究了饲粮中添加不同剂量的富硒五谷虫粉对生长育肥猪生长性能、血清生化指标、屠宰性能和肉品质的影响。试验选用72头体况健康、体重21 kg左右60日龄“杜×长×大”生长育肥猪,随机分为3组,每组6个重复,每个重复4头猪。对照组饲喂基础饲粮,0.1%组、0.2%组分别在基础饲粮中添加1 kg/t和2 kg/t的富硒五谷虫粉。试验期17周。结果显示,与对照组相比,饲粮添加0.1%富硒五谷虫粉可显著提高生长育肥猪的平均日增重(P<0.05);0.2%富硒五谷虫粉可以显著提高生长育肥猪血清免疫球蛋白A含量及谷胱甘肽过氧化物酶、超氧化物歧化酶的活性(P<0.05),显著降低血清丙二醛含量(P<0.05);饲粮添加0.1%、0.2%富硒五谷虫粉可增加生长育肥猪背最长肌中肌内脂肪、硒、亚油酸、α-亚油酸、花生酸、二十碳烯酸和二十碳二烯酸含量。研究表明,饲粮添加富硒五谷虫粉可以提高生长育肥猪的生长性能、免疫和抗氧化能力,改善猪肉的营养价值。

中药-益生菌制剂对生长育肥猪生长性能、胴体性能和肉品质的影响

本试验旨在研究日粮添加中药-益生菌制剂对生长育肥猪生长性能、胴体性能和肉品质的影响。试验选用30头100日龄、体重相近的杜×长×大三元杂交生长育肥猪随机分为5组,每组6头,分别为对照组(基础日粮)、试验1组(基础日粮+0.5%中药-益生菌制剂)、试验2组(基础日粮+1.0%中药-益生菌制剂)、试验3组(基础日粮+1.5%中药-益生菌制剂)和试验4组(基础日粮+2%中药-益生菌制剂)。预试期10 d,正试期30 d。结果表明,与对照组相比,试验1、2、3和4组平均日采食量分别提高了0.81%(P>0.05)、2.02%(P<0.05)、12.10%(P<0.01)和12.10%(P<0.01),平均日增重分别提高了7.2%(P>0.05)、18.07%(P<0.01)、26.51%(P<0.01)和22.89%(P<0.01),末重分别提高了3.69%(P>0.05)、9.03%(P<0.05)、13.28%(P<0.05)和11.45%(P<0.05),料重比分别降低了1.34%(P>0.05)、2.68%(P>0.05)、3.30%(P<0.05)和3.01%(P>0.05)。试验2、3、4组宰前活重显著高于试验1组和对照组(P<0.05);试验3组背膘厚显著低于其他各组(P<0.05)。试验3组的剪切力和失水率显著低于对照组(P<0.05);熟肉率显著高于其他各组(P<0.05);各组的pH45min和pH24h指标差异不显著(P>0.05)。因此,试验3组在促进生长育肥猪的生长、提高屠宰性能和改善肉品质方面效果最佳。

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。

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。

饲粮添加L-肉碱对生长育肥母猪生长性能、胴体品质和肉品质的影响

本试验旨在研究饲粮添加L-肉碱对生长育肥母猪生长性能、胴体品质和肉品质的影响。选取体重[(30.42±3.24)kg]相近的PIC商品母猪420头,随机分为2组,每组7个重复,每个重复30头。对照组饲喂基础饲粮,试验组在基础饲粮的基础上添加100 mg/kg L-肉碱。试验期共计105 d。结果表明:1)与对照组相比,试验组生长育肥母猪各阶段平均日增重、平均日采食量、料重比和存活率均无显著差异(P>0.05)。2)与对照组相比,饲粮添加L-肉碱显著提高生长育肥母猪背膘厚度、背最长肌长度和重量(P<0.05),显著降低下颌脂肪指数(P<0.05),显著降低背最长肌剪切力、滴水损失、肌纤维直径和面积(P<0.05),显著提高背最长肌肌纤维密度(P<0.05)。3)与对照组相比,饲粮添加L-肉碱提高生长育肥母猪背最长肌肌内脂肪含量(P<0.05),但显著降低背最长肌亚油酸、花生酸和花生三烯酸含量(P<0.05)。4)与对照组相比,饲粮添加L-肉碱显著提高生长育肥母猪背最长肌脂肪酸合成酶(FAS)mRNA相对表达量(P<0.05),显著降低背最长肌肌球蛋白重链Ⅱb(MyHCⅡb)mRNA相对表达量(P<0.05)。综上所述,饲粮添加100 mg/kg L-肉碱对生长育肥母猪生长性能无显著影响,但可以影响背最长肌肌内脂肪沉积和肌纤维性状,并改善胴体品质和肉品质。

苜蓿草粉对育肥猪生长性能、肉品质及经济效益的影响

试验旨在研究不同水平苜蓿草粉对生长育肥猪生长性能、肉品质及经济效益的影响。选用体重约为55 kg的“杜×长×大”生长育肥猪160头,随机分为4组,每组4个重复,每个重复10头猪。各组猪分别饲喂含有0(对照组)、5%、10%和20%苜蓿草粉的试验日粮。试验期8周。结果显示,与对照组相比,20%苜蓿草粉组猪的末重、平均日增重和平均日采食量显著降低(P<0.05),料重比显著提高(P<0.05)。20%苜蓿草粉组猪的宰前活重显著低于其他组(P<0.05),胴体重显著低于对照组和5%苜蓿草粉组(P<0.05),瘦肉率显著高于其他组(P<0.05)。10%苜蓿草粉组和20%苜蓿草粉组猪的背膘厚度显著低于对照组(P<0.05)。5%苜蓿草粉组和10%苜蓿草粉组猪背最长肌的pH24 h值显著高于对照组和20%苜蓿草粉组(P<0.05),10%苜蓿草粉组和20%苜蓿草粉组猪背最长肌的剪切力显著低于对照组(P<0.05)。10%紫花苜蓿草粉组猪背最长肌中粗蛋白含量显著高于对照组和20%苜蓿草粉组(P<0.05),10%苜蓿草粉组和20%苜蓿草粉组猪背最长肌中的水分含量显著高于对照组(P<0.05)。各组利润分别为314.06、317.90、307.31、251.97元。研究表明,在养殖中使用5%苜蓿草粉替代部分玉米与豆粕原料对育肥猪的生长性能及经济效益未产生负面影响,还可以改善部分肉品质指标。

日粮中添加葡萄籽原花青素对育肥猪生长性能及血液生化指标的影响

文章旨在研究日粮中添加葡萄籽原花青素(Gsp-s)对生长育肥猪血液生化指标的调节作用及对生长性能的影响,试验将128头育肥猪随机分为4组,每组4个重复,每个重复8头猪,对照组饲喂基础日粮,P1、P2、P3组分别在基础日粮中添加10g、200、300 mg/kg Gsp-s,试验为期45 d。结果显示,各组料重比无显著差异(P>0.05);P1、P2组平均日采食量(ADFI)、日平均增重(ADG)、末重(FW)均显著高于对照组、P3组(P<0.05);P1组、P2组血清尿素氮(UN)含量显著低于对照组、P3组(P<0.05);与P1组、P3组和对照组相比,P2组血清球蛋白(GLB)、白蛋白(ALB)含量显著提高(P<0.05),低密度脂蛋白(LDL-C)、甘油三酯(TG)水平显著降低(P<0.05)。从本试验所得结果可以看出,育肥猪日粮中添加葡萄籽原花青素后,对生长性能指标及血液生化指标变化有明显影响,其中以200 mg/kg的添加效果最佳。