Effects of dietary Clostridium butyricum and rumen protected fat on meat quality,oxidative stability,and chemical composition of finishing goats

Background Clostridium butyricum(CB)is a probiotic that can regulate intestinal microbial composition and improve meat quality.Rumen protected fat(RPF)has been shown to increase the dietary energy density and provide essential fatty acids.However,it is still unknown whether dietary supplementation with CB and RPF exerts beneficial effects on growth performance and nutritional value of goat meat.This study aimed to investigate the effects of dietary CB and RPF supplementation on growth performance,meat quality,oxidative stability,and meat nutritional value of finishing goats.Thirty-two goats(initial body weight,20.5±0.82 kg)were used in a completely randomized block design with a 2 RPF supplementation(0 vs.30 g/d)×2 CB supplementation(0 vs.1.0 g/d)factorial treatment arrangement.The experiment included a 14-d adaptation and 70-d data and sample collection period.The goats were fed a diet consisted of 400 g/kg peanut seedling and 600 g/kg corn-based concentrate(dry matter basis).Result Interaction between CB and RPF was rarely observed on the variables measured,except that shear force was reduced(P<0.05)by adding CB or RPF alone or their combination;the increased intramuscular fat(IMF)content with adding RPF was more pronounced(P<0.05)with CB than without CB addition.The pH24h(P=0.009),a*values(P=0.007),total antioxidant capacity(P=0.050),glutathione peroxidase activities(P=0.006),concentrations of 18:3(P<0.001),20:5(P=0.003)and total polyunsaturated fatty acids(P=0.048)were increased,whereas the L*values(P<0.001),shear force(P=0.050)and malondialdehyde content(P=0.044)were decreased by adding CB.Furthermore,CB supplementation increased essential amino acid(P=0.027),flavor amino acid(P=0.010)and total amino acid contents(P=0.024)as well as upregulated the expression of lipoprotein lipase(P=0.034)and peroxisome proliferator-activated receptorγ(PPARγ)(P=0.012),and downregulated the expression of stearoyl-CoA desaturase(SCD)(P=0.034).The RPF supplementation increased dry matter intake(P=0.005),averaged daily gain(trend,P=0.058),hot carcass weight(P=0.046),backfat thickness(P=0.006),concentrations of 16:0(P<0.001)and c9-18:1(P=0.002),and decreased the shear force(P<0.001),isoleucine(P=0.049)and lysine content(P=0.003)of meat.In addition,the expressions of acetyl-CoA carboxylase(P=0.003),fatty acid synthase(P=0.038),SCD(P<0.001)and PPARγ(P=0.022)were upregulated due to RPF supplementation,resulting in higher(P<0.001)content of IMF.Conclusions CB and RPF could be fed to goats for improving the growth performance,carcass traits and meat quality,and promote fat deposition by upregulating the expression of lipogenic genes of Longissimus thoracis muscle.

Assessment of the Effects of Supplemental Rumen Protected B Vitamins and Choline for Periparturient Cows: A Meta-Analysis of 28 Feeding Studies

There are currently no prescribed requirements for B vitamins or choline for dairy cows during the transition period, but many recent studies have shown a variety of benefits from supplying these nutrients to periparturient cows. The purpose of this research effort was to determine the potential benefit of including a rumen protected blend composed of B vitamins (riboflavin, folic acid, vitamin B12) and choline (RPBlend, Jefo Nutrition Inc., St. Hyacinthe, QC, Canada) for dairy cows during the transition period, based on results from 28 on-farm feeding studies (USA-12, Mexico-7, Canada-4, Chile-3, Australia-1, Brazil-1) conducted between 2011 and 2018. All farms participated in monthly herd management record keeping systems and were selected to participate in studies due to their excellent management. Meta-analyses in which risk differences were determined were used to assess the effects of the supplemental RPBlend on health parameters and reproduction. The effect size was used as the determinant of the possible contribution of RPblend on the yields of milk, energy corrected milk (ECM), fat and protein yields during the first four weeks of lactation. Results showed that the inclusion of RPblend reduced (P < 0.05) involuntary culling and mastitis by cows during the first 30 days after calving. There was a tendency (P < 0.10) for reduced retained placenta and metritis. The meta-analyses revealed that the risk of the displaced abomasum and milk fever did not diminish (P > 0.10) with the inclusion of the BPBlend. The incidence rate of subclinical ketosis, determined as blood beta hydroxy butyric acid greater than 1.2 mM was lower (P (than those not supplemented. The proportion of cows confirmed pregnant by 100 days in milk was greater for cows given the BPBlend (P < 0.05). Milk yield and ECM were greater for cows receiving the RPBlend (1.13 and 0.93 kg/cow respectively, P < 0.05). There was no change in fat yield (P > 0.10) while the yield of milk protein was greater (P < 0.05) when the cows received the blend. These results suggest that the inclusion of rumen protected B vitamins and choline can assist cow health, reproduction and production at the start of lactation.

Assessment of Lactational Performance in Dairy Cows Receiving a Rumen Protected B Vitamin Blend during Lactation: Part 1: A Meta-Analysis of 50 Studies

The objective of this research was to evaluate the impact of a dietary supplemental rumen protected B vitamin blend (RPBV: Folic acid, B12, pyridoxine, pantothenic acid, and biotin;Jefo, St. Hyacinthe, QC Canada) on milk, fat, and protein yield in cows past peak lactation. Results from 50 double reversal design trials (control-test-control) were evaluated using meta-analyses. All herds participated in monthly milk recording services, and all were Holstein herds. Within each of the 50 trials, cows included in the statistical analysis were over 45 days in milk (DIM) at the first milk test, averaged 159 ± 26 DIM on the first test date, and were available for all milk collection periods. A total of 6483 cows from 7 countries were represented in the 50 studies, with an average herd size of 129.7 ± 118.0. Meta-analyses were conducted to determine effect size for milk, fat, and protein yield based on the treatment differences and standard errors (SE) from the individual trials. Results indicated that dairy cows responded positively to the inclusion of the rumen protected B vitamin blend. Forest plots revealed trial-to-trial variation and might be related to age, level of milk production, and stage of lactation of the cows.

Protective Effects of Rumen Protected Choline in Dairy Cows

Choline is a necessary nutrient for dairy cows and contributes to milk yield, but most of dietary choline can be degraded by the microorganisms in rumen. Rumen protected choline （RPC） has been developed to protect choline from degradation. To screen stable RPC, choline chloride was coated with acrylic resin no. IV, chitosan and the mixture containing the two lagging covers by fluidized bed coating technology, respectively. Their stability was evaluated in vitro and in situ. The results showed that release rate of RPC coated with acrylic resin no. IV and chitosan was the lowest in rumen and pH 6.6 buffer. And its effective protection rate reached 62.04% in rumen. Therefore, RPC coated with acrylic resin no. IV and chitosan has good stability and protection efficacy in rumen, and it can be used in practice to supply effective choline for the ruminant.

Methods to Evaluate Rumen Protected Lysine for Dairy Cows

There are many rumen protected amino acid products available for dairy cattle feeding. However, feed formulation programs require values related to rumen solubility, rate of disappearance in the rumen and total tract digestibility and often such values are not available. In vivo testing procedures are complex, time consuming and expensive. This study was conducted to determine if a newrapid, lower cost in vitro method developed for feed ingredients could be applied to a rumen protected lysine product (DairynatLys-30, Jefo Nutrition Inc). In vivo determination of the rapidly solubilized protein fraction, rate of degradation of the slowly solubilized fraction and total tract digestibility studies were compared to the in vitro method in use in many ingredient analysis laboratories for feed ingredients such as forages, protein supplements and grains. Results showed that the rapidly soluble fraction (8.33% and 8.66% of total N for in vivo and in vitro methods) and rates of disappearance in the rumen (2.64%/h and 2.43%/h for in vivo and in vitro procedures) compared favorably between the two methods for the rumen protected product. Total tract digestibility values were slightly higher (84.4%) with the in vivo method used than with the in vitro method (75.9%), and both are in the expected calculated range of digestibility of 80%. In conclusion the in vitro method appears to be an acceptable alternative for evaluating rumen protected amino acids.

Assessment of Lactational Performance in Dairy Cows Receiving a Rumen Protected B Vitamin Blend during Lactation: Part 2: A Regression Analysis of 50 Studies

A previous series of meta-analyses demonstrated that a protected blend of B vitamins (RPBV: folic acid, B12, pyridoxine, pantothenic acid, and biotin;Jefo, St. Hyacinthe, QC, Canada) improved milk fat and protein yield, with variation in the extent of the response. These results represent additional analyses of the same dataset to determine if the degree of response to RPVB on milk, fat and protein yield might be related to the level of production, lactation number, or days in milk (DIM). Results from 50 on-farm switchback trials conducted in 7 countries between 2005 and 2015 were included in the analysis. All herds participated in monthly milk recording services, and all were Holstein herds. A total of 6483 cows, averaging 163 DIM on the first test date, participated in the studies. Data were analyzed using regression models that accounted for the effects of trial, period, days in milk (DIM) and lactation number on milk and component yield. Milk yield and fat yield increased with B vitamin inclusion, and the extent of change was determined to increase with lactation number (P < 0.05). Protein yield increased with the RPBV and was unaffected by lactation number (P < 0.05) Responses to the RPBV occurred throughout lactation but were found to decline with DIM for milk, fat and protein yield. The global equation revealed that milk yield with the rumen-protected B vitamin blend = 4.05 + [0.917 × control milk] - [0.0063 × DIM] + [0.246 × Lactation number] (R2 = 0.798) The use of regression models allows changes in milk, fat and protein yields with the rumen-protected B vitamin blend to be more accurately predicted.

过瘤胃氨基酸在反刍动物中的应用进展

反刍动物的瘤胃微生物消化具有特殊性,在饲粮中直接添加未经处理的氨基酸,大部分会被瘤胃微生物降解,这不仅会造成氨基酸浪费,还会增加氮排放造成的环境污染,因此需要对氨基酸进行过瘤胃保护。目前过瘤胃保护技术主要包括包被技术、化学技术和生物技术。蛋氨酸和赖氨酸是反刍动物的主要限制性氨基酸,在饲粮中添加过瘤胃赖氨酸(RPL)和过瘤胃蛋氨酸(RPM)能够提高反刍动物生长性能,促进饲料养分消化吸收,改善反刍动物产品品质。文章就反刍动物氨基酸营养、过瘤胃氨基酸加工技术以及过瘤胃氨基酸在反刍动物生产中的应用进行综述,以期为反刍动物的氨基酸营养研究提供参考。

低蛋白质饲粮补加过瘤胃赖氨酸对多浪羊生长性能、养分表观消化率、瘤胃发酵参数及氮代谢的影响

本试验旨在研究低蛋白质饲粮补加过瘤胃赖氨酸(RPLys)对多浪羊生长性能、养分表观消化率、瘤胃发酵参数及氮代谢的影响。将9只体况相近且安装永久性瘘管的多浪羊羯羊,采用3×3拉丁方设计,随机分为3组:CK组(饲喂14%蛋白质水平的饲粮)、DP组(饲喂12%蛋白质水平的饲粮)、LP组(饲喂12%蛋白质水平饲粮+14.0 g/d RPLys)。试验分3期进行,每期28 d,其中预试期15 d,正试期13 d。结果表明:1)各组间的初重及干物质采食量(DMI)无显著差异(P>0.05),LP组的平均日增重(ADG)极显著高于CK组和DP组(P<0.01),CK组和DP组的ADG差异不显著(P>0.05),LP组的料重比(F/G)显著低于CK组和DP组(P<0.05),CK组和DP组的F/G差异不显著(P>0.05)。2)各组间干物质(DM)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)和粗脂肪(EE)表观消化率差异不显著(P>0.05);LP组粗蛋白质(CP)表观消化率极显著高于CK组和DP组(P<0.01),CK组CP表观消化率极显著高于DP组(P<0.01);LP组有机物(OM)表观消化率极显著高于CK组和DP组(P<0.01),CK组和DP组OM表观消化率差异不显著(P>0.05)。3)低蛋白质饲粮补加RPLys对多浪羊瘤胃氨态氮(NH3⁃N)、丁酸(BA)和戊酸(VA)含量无显著影响(P>0.05);DP组和LP组微生物蛋白(MCP)含量极显著高于CK组(P<0.01);LP组乙酸(AA)和丙酸(PA)含量极显著高于CK组和DP组(P<0.01),CK组和DP组AA和PA含量差异不显著(P>0.05);CK组乙酸/丙酸极显著高于LP组(P<0.01);LP组总挥发性脂肪酸(TVFA)含量极显著高于CK组和DP组(P<0.01),CK组和DP组TVFA含量差异不显著(P>0.05)。4)各组间多浪羊进食氮、尿氮、粪氮、总排出氮、沉积氮、氮利用率和氮生物学价值均差异不显著(P>0.05),但与CK组相比,DP组与LP组的粪氮有降低的趋势(0.05<P<0.10),且DP组与LP组的氮利用率和氮生物学价值分别提高了6.55%、14.09%和2.58%、11.06%。综上所述,低蛋白质饲粮补加14.0 g/d RPLys能够提高多浪羊的ADG以及CP和OM表观消化率,促进MCP的合成效率,增加挥发性脂肪酸产量,并提高氮利用率和生物学价值。

体外发酵法评估呼伦贝尔羊瘤胃对过瘤胃蛋氨酸的生物利用率及过瘤胃蛋氨酸对瘤胃微生物的影响

为了探究呼伦贝尔羊瘤胃体外发酵体系对过瘤胃蛋氨酸(RPMet,由玉米淀粉和棕榈油包被)的生物利用率及过瘤胃蛋氨酸对瘤胃微生物类群的影响,取4只装有瘘管的雌性呼伦贝尔羊的瘤胃液进行体外发酵试验,在发酵起始阶段与发酵后2 h、4 h、6 h、8 h、12 h、24 h测定发酵体系中的RPMet降解率。每个发酵时间节点设置5个平行处理,在以上7个时间节点取发酵液并进行16S rDNA测序分析。结果表明,在体外发酵体系中,RPMet在发酵后8 h的降解率小于30.0%,说明该产品的包被效果较好。测序结果显示,发酵24 h后的Simpson指数显著低于发酵12 h后的Simpson指数(P<0.05)。主坐标分析(PCoA)能够显示物种的β-多样性,本研究结果显示,各时间点的聚类结果皆存在显著差异(P<0.05)。拟杆菌门、瘤胃球菌属、普雷沃氏菌属菌的相对丰度在发酵后8 h内显著上升,发酵12 h后显著下降(P<0.05)。厚壁菌门、广古菌门、甲烷杆菌属、解琥珀酸菌属、颤螺菌属菌的相对丰度在发酵后12 h内显著下降,之后显著上升(P<0.05)。综上所述,研究中所用的RPMet的包被效果较好,且发酵前期主要是普雷沃氏菌属、瘤胃球菌属微生物降解玉米淀粉包被层,而RPMet的过度降解显著提高了甲烷杆菌属微生物的相对丰度。

高浓度过瘤胃脂肪粉对绵羊葡萄糖和胰岛素耐量的影响

【目的】探讨高浓度过瘤胃脂肪粉(rumen protected fat,RPF)对绵羊的生长育肥性能以及葡萄糖动力学和胰岛素抵抗的影响,旨在为RPF在绵羊饲粮中的应用提供理论依据。【方法】选取体况良好的3月龄呼伦贝尔羊160只,随机分为2组,每组4个重复,每个重复20只羊,分别为CON组(不添加RPF、36.95%玉米)和HF组(23.65%RPF、16.34%玉米),预饲期为14 d,正饲期为42 d,每天记录绵羊采食量,每21 d监测1次体重变化,计算每组绵羊的平均日采食量(ADFI)、平均日增重(ADG)和料重比(F/G)。正饲期结束后,两组各选4只绵羊进行静脉注射葡萄糖耐量试验(intravenous glucose tolerance test,IVGTT),按照0.25 g/kg BW颈静脉注射50%葡萄糖溶液,采集颈静脉血液,测量血清中的葡萄糖和胰岛素浓度,计算其曲线下方正增量面积、最大浓度、最大浓度变化量及胰岛素抵抗指数(HOMA-IR和Matsuda指数)。【结果】与CON组相比,HF组的ADFI和F/G显著降低(P<0.05)。在IVGTT期间,与CON组相比,HF组绵羊在2、10、30 min时的血清葡萄糖浓度及试验期间的葡萄糖曲线下方正增量面积均显著降低(P<0.05),HF组的血清葡萄糖最大浓度显著低于CON组(P<0.05);HF组在10和30 min时血清胰岛素浓度及其在60 min时曲线下方正增量面积均显著低于CON组(P<0.05)。HF组的Matsuda指数显著高于CON组(P<0.05)。【结论】综上所述,在生长绵羊饲粮中添加高浓度RPF不会影响绵羊的生长性能,并且可以降低绵羊血清葡萄糖浓度,提升胰岛素敏感性。

添加过瘤胃氨基酸低蛋白质饲粮对呼伦贝尔羊生长性能、养分表观消化率及肉品质的影响

旨在探究低蛋白质日粮中添加过瘤胃蛋氨酸(RPMet)和过瘤胃赖氨酸(RPLys)对呼伦贝尔羊生长性能、养分表观消化率、血清生化及肉品质的影响。选择2.5月龄断奶健康羔羊16只,编号后随机等分为2组,分别为对照组(Control group,饲喂低蛋白质日粮,粗蛋白质含量为7.84%)和试验组(Treatment group,在低蛋白质日粮基础上补充10 g·d^(-1) RPMet和15 g·d^(-1) RPLys)。预试期7 d,正试期56 d。结果显示:1)试验组的平均日采食量较对照组显著降低(P<0.05),但其平均日增高显著高于对照组(P<0.05),试验组的料重比较对照组有降低的趋势。2)两组间的屠宰性能和养分表观消化率均无显著差异(P>0.05)。3)试验组血清中的总蛋白(TP)、白蛋白(ALB)、肌酐(CREA)、乳酸脱氢酶(LDH)、谷丙转氨酶(ALT)和低密度脂蛋白(LDL)的含量显著低于对照组(P<0.05),游离脂肪酸(NEFA)含量显著高于对照组(P<0.05)。4)两组间背肌的肉色、常规营养成分、脂肪酸组成和含量无显著差异(P>0.05)。试验组肌肉中苏氨酸(Thr)含量较对照组显著升高(P<0.05),异亮氨酸(Ile)、亮氨酸(Leu)、酪氨酸(Tyr)的含量较对照组显著降低(P<0.05),试验组肌肉中风味氨基酸和必需氨基酸占总氨基酸的比例(DAA/TAA、EAA/TAA)显著高于对照组(P<0.05),必需氨基酸与非必需氨基酸的比值(EAA/NAA)显著高于对照组(P<0.05)。综上,在本试验条件下,低蛋白质饲粮中添加10 g·d^(-1) RPMet和15 g·d^(-1) RPLys对呼伦贝尔羊的生长发育有积极作用,且不会影响其养分消化率和屠宰性能,并能增加肌肉中的风味氨基酸和必需氨基酸的占比,提升羊肉的风味和营养价值。

过瘤胃蛋氨酸对牦牛半腱肌肉品质、挥发性风味物质及脂肪酸组成的影响

旨在探究过瘤胃蛋氨酸对牦牛半腱肌肉品质、挥发性风味物质及脂肪酸组成的影响。选用4岁、体重为(252.79±15.95)kg的健康麦洼公牦牛24头,将其随机分为4组:基础日粮(CON)、基础日粮加5 g·d^(-1)过瘤胃蛋氨酸(RPM1)、基础日粮加10 g·d^(-1)过瘤胃蛋氨酸(RPM2)和基础日粮加15 g·d^(-1)过瘤胃蛋氨酸(RPM3),预饲10 d,舍饲70 d后屠宰。结果表明,RPM3组脂肪含量显著高于RPM1组与RPM2组(P<0.05);RPM1组、RPM2组、RPM3组的粗蛋白含量均显著高于CON组(P<0.05)。牦牛半腱肌样品中共检验出42种挥发性风味物质,通过相对气味活度值计算发现,CON组、RPM1组、RPM2组和RPM3组关键挥发性风味物质分别有9种、11种、9种和10种,关键挥发性风味物质为牦牛半腱肌提供了独特的肉香与油脂香等;CON组、RPM1组与RPM2组的主要挥发性风味物质为壬醛,而RPM3组的主要挥发性物质为1-辛烯-3-醇;RPM1组的醛类物质含量最高,且具有独特的水果香味与坚果味,RPM2组的醇类与烃类物质的种类最多。四组半腱肌样品中共检测出16种脂肪酸。半腱肌CON组饱和脂肪酸总量显著低于RPM1组和RPM2组(P<0.05),其中RPM1组与RPM2组棕榈酸含量显著高于其他组(P<0.05),RPM1组二十二碳酸含量显著高于CON组和RPM3组(P<0.05);RPM1组单不饱和脂肪酸总量著高于RPM2组与RPM3组(P<0.05),其中RPM1组肉豆蔻油酸含量显著低于其他组(P<0.05),CON组十七碳烯酸含量显著高于其他组(P<0.05),RPM1组二十四碳烯酸含量显著高于RPM2组(P<0.05);各组间半腱肌多不饱和脂肪酸总量无差异(P>0.05)。综上所述,日粮添加10 g·d^(-1)的过瘤胃蛋氨酸组牦牛半腱肌中风味丰富度与挥发性风味物质含量最高;日粮添加5 g·d^(-1)过瘤胃蛋氨酸组牦牛半腱肌中脂肪酸含量最高,且分布合理。

不同蛋白水平饲粮中添加过瘤胃赖氨酸对牦牛生长性能、养分消化、血清生化及瘤胃发酵参数的影响

本试验旨在研究不同蛋白水平饲粮中添加过瘤胃赖氨酸(RPLys)对牦牛生长性能、养分表观消化率、血清生化指标及瘤胃发酵参数的影响,为将RPLys应用于牦牛养殖提供技术参考。试验采用2×3因子试验设计,分别为2种饲粮蛋白水平(低蛋白饲粮:12.98%,高蛋白饲粮:14.99%)和3种RPLys添加水平(0%、0.15%和0.30%,干物质基础)。选取36头(237.00±35.96)kg年龄为4周岁左右的健康公牦牛随机分为6组(Ⅰ组:低蛋白基础饲粮,Ⅱ组:低蛋白饲粮添加0.15%RPLys,Ⅲ组:低蛋白饲粮添加0.30%RPLys,Ⅳ组:高蛋白基础饲粮,Ⅴ组:高蛋白饲粮添加0.15%RPLys,Ⅵ组:高蛋白饲粮添加0.30%RPLys),每个处理组6个重复,每个重复1头牦牛。预饲期7 d,正饲期60 d。结果表明:(1)平均日增重在RPLys添加量主效应中以0.30%组最佳,显著高于基础饲粮组(P<0.05),在两因素交互作用中,以Ⅲ组最高,显著高于Ⅰ组(P<0.05);料重比在RPLys添加量主效应中以0.30%组最佳,显著低于基础饲粮组和0.15%组(P<0.05),在两因素交互作用中,以Ⅲ组最佳,显著高于Ⅰ组(P<0.05)。(2)在蛋白水平主效应中,高蛋白饲粮组有机物(OM)表观消化率显著低于低蛋白饲粮组,高蛋白饲粮组粗蛋白质(CP)、中性洗涤纤维(NDF)及酸性洗涤纤维(ADF)极显著低于低蛋白饲粮组(P<0.01),在两因素交互作用中,以Ⅲ组最佳,其OM、CP、NDF及ADF均显著高于Ⅰ组(P<0.05)。(3)在RPLys添加水平主效应中,添加0.15%和0.30%组丙氨酸氨基转移酶、葡萄糖、尿素、总蛋白、天门冬氨酸氨基转移酶、白蛋白、球蛋白、肌酐、胰岛素(INS)及胰岛素样生长因子1(IGF-1)相比基础饲粮组均显著升高(P<0.05),在两因素交互作用中,INS在Ⅵ组最高,显著高于Ⅰ组(P<0.05)。(4)在RPLys添加水平主效应中,添加0.15%和0.30%组游离氨基酸均显著低于基础饲粮组,在两因素交互作用中,以Ⅴ组最低,显著低于Ⅰ组(P<0.05)。(5)在蛋白水平主效应中,高蛋白饲粮组氨态氮及各组分挥发性脂肪酸含量均显著高于低蛋白饲粮组,乙酸/丙酸比显著低于低蛋白饲粮组(P<0.05),在RPLys添加水平主效应中,0.15%和0.30%组微生物蛋白均显著低于基础饲粮组(P<0.05)。综上,本研究得出,在低蛋白基础饲粮组中添加0.30%RPLys效果最佳,能显著改善牦牛的生产性能。

围产期补充过瘤胃蛋氨酸对奶牛生产性能和免疫能力影响的研究进展

围产期是奶牛生产周期中较为关键的时期,此阶段奶牛机体容易出现能量负平衡、免疫力低下等问题。蛋氨酸作为奶牛机体内具有限制性的必需氨基酸,不仅发挥营养调控作用,还具有调节奶牛繁殖能力、免疫能力和生长性能等功能。该文对围产期补充过瘤胃蛋氨酸对奶牛生产性能和免疫能力影响的研究进展进行阐述,以期为过瘤胃蛋氨酸产品在奶牛围产期的科学应用提供理论参考。

不同瘤胃保护性胆碱对围产后期奶牛酮病发病率和血液代谢指标的影响

本试验通过尼龙袋降解试验和饲喂试验,比较两种过瘤胃胆碱的干物质降解率和胆碱保护率及其对围产期奶牛酮病发病率和血液代谢指标的影响。研究分为两个部分:试验一使用尼龙袋法在瘤胃瘘管奶牛上对两种过瘤胃胆碱(A为对照组,B为试验组)的干物质降解率和胆碱保护率进行测定。试验二选取广西某规模化奶牛场的围产牛,采用分阶段对比试验设计,于产前21d开始至分娩分别饲喂含过瘤胃氯化胆碱A和过瘤胃氯化胆碱B的日粮;试验期间全混合日粮(TMR)配方保持不变。试验结果表明:与对照组相比,试验组胆碱的瘤胃干物质降解率较低,过瘤胃保护率较高。试验组奶牛酮病发病率较低;在产后14d和21d,试验组奶牛血液葡萄糖浓度显著增加。综上,根据瘤胃保护率、奶牛酮病发病率和血液代谢试验结果可知,试验组过瘤胃胆碱优于对照组。

蛋白的过瘤胃保护技术及应用进展

过瘤胃蛋白是指日粮中的蛋白质在消化过程中,未被反刍动物瘤胃降解而直接进入小肠的部分。日粮中的过瘤胃蛋白含量与蛋白原料类型有关,不同蛋白原料在瘤胃的降解率相差甚大,可提供的过瘤胃蛋白含量也各不相同。因此,利用过瘤胃保护技术,对蛋白原料进行适当的加工处理,可以减少甚至避免微生物对其的降解,使更多的蛋白通过瘤胃在小肠中被消化吸收。本文就几种常见的蛋白过瘤胃技术及其应用效果与存在的问题进行了综述。

胆碱和赖氨酸过瘤胃保护效果及对奶牛生产性能的影响

[目的]评估过瘤胃胆碱和过瘤胃赖氨酸产品的保护率、降解率及其对生产性能的影响,旨在为过瘤胃技术的发展及应用提供参考。[方法]通过瘤胃稳定性试验、体外模拟小肠消化试验对过瘤胃胆碱和过瘤胃赖氨酸产品的过瘤胃保护效果进行测定,同时以荷斯坦奶牛为例,选取体质量为600 kg左右且泌乳期约60 d的健康荷斯坦奶牛40头,随机分为4组,每组10头,分别为胆碱组(日粮中补充30 g/(头·d)过瘤胃胆碱)、赖氨酸组(日粮中补充30 g/(头·d)的过瘤胃赖氨酸)、胆碱+赖氨酸组(日粮中补充过瘤胃胆碱和过瘤胃赖氨酸各30 g/(头·d))和对照组(不添加过瘤胃胆碱与赖氨酸),分别测定日均干物质采食量、日均产奶量、乳脂率、乳蛋白率。[结果]过瘤胃胆碱和过瘤胃赖氨酸处理2 h的过瘤胃保护率均在84%以上,2 h时小肠降解率分别为79.23%和81.76%;与对照组相比,日粮中添加过瘤胃胆碱、过瘤胃赖氨酸、过瘤胃胆碱和过瘤胃赖氨酸的干物质采食量分别显著增加11.20%、8.06%、11.76%,日均产奶量分别显著增加8.02%、7.86%、9.53%;各组之间乳蛋白率没有显著差异。[结论]饲粮中添加过瘤胃胆碱和过瘤胃赖氨酸均具有良好的过瘤胃保护效果和小肠释放效果,可不同程度提高奶牛的生产性能。

过瘤胃氨基酸对反刍动物生产性能及氮排放的影响

[目的]研究过瘤胃赖氨酸(RPLys)、过瘤胃蛋氨酸(RPMet)对反刍动物生产性能及氮排放的影响。[方法]以荷斯坦牛为例,选用40头体重600 kg左右且泌乳期60 d左右的健康荷斯坦牛进行试验,随机分为4组,每组10头,分别为L组(日粮中补充30 g/头·d RPLys)、M组(日粮中补充30 g/头·d RPMet)、LM组(日粮中补充RPLys、RPMet各30 g/头·d)和CK组(不添加RPLys、RPMet),分别测定日均干物质采食量、日均产奶量、乳脂率、乳蛋白率、乳糖率、乳体细胞数、粪氮、尿氮、氮总排放量。[结果]与CK组相比,L组、M组、LM组日均干物质采食量、乳糖率无显著变化(P>0.05),日均产奶量、乳蛋白率显著增加(P<0.05),乳体细胞数、粪氮、尿氮、氮总排放量均显著降低(P<0.05);L组乳脂率无显著变化(P>0.05),M组、LM组乳脂率显著增加(P<0.05)。[结论]RPLys和RPMet可改善奶牛生产性能,调节乳房健康水平,降低氮排放,减少环境污染,助力畜牧业绿色高效发展。

瘤胃保护蛋氨酸在泌乳牛营养调控中的作用及其影响因素

泌乳牛的健康和生产性能对畜牧业可持续发展至关重要。瘤胃保护蛋氨酸(RPM)作为一种重要饲料添加剂,在泌乳牛中应用广泛。补饲RPM可显著改善泌乳牛的生产性能、健康状态、饲料利用效率、繁殖性能等,但其效果受饲料配方、饲养管理水平和环境条件、个体差异等多种因素影响。本文综述RPM在泌乳牛营养调控中的作用及其影响因素,为其研究、应用提供理论基础和技术参考。

补饲过瘤胃蛋氨酸对围产期奶牛健康及生产性能影响的研究进展

围产期是奶牛生产周期的关键时期,面临生理和代谢挑战,包括免疫力减弱和能量负平衡。近年来研究表明,通过补饲过瘤胃蛋氨酸可改善围产期奶牛的健康状况和生产性能。本文阐述奶牛围产期、过瘤胃蛋氨酸的重要性、补饲过瘤胃蛋氨酸对围产期奶牛健康和生产性能的影响,以期为蛋氨酸在奶牛围产期营养调控研究和应用提供理论基础。