Effect of heat treatment and subsequent urea supplementation of sunflower meal on the in vitro ruminal degradability of crude protein content and its postruminal digestibility

A three-phase laboratory procedure was used for predicting the degradability of the protein of extracted sunflower meal before (SFM) and after heat treatment (HSFM). The rumen fluid degraded 69.1% and 67.1% of the SFM and HSFM protein, respectively. The digestibility values of rumen undegraded protein (UDP) were 57.3% (SFM) and 57.0% (HSFM) with pepsin and 17.6% (SFM) and 15.9% (HSFM) with pancreatin. Urea supplementation practically did not alter the rumen degradability of HSFM protein, while the pepsin digestibility of UDP decreased to 47.2%. Four fractions (NH3, dissolved amino acids, oligopeptides and proteins) of rumen degradable crude protein (RDP) were also determined in vitro: 81 to 92% of the degraded crude protein was found in the fractions tested. Heat treatment reduced free NH3 content but did not alter the other three fractions. Urea supplementation decreased the quantity of NH3, peptides and proteins as well.     

The effect of tannin treatment and subsequent urea supplementation of sunflower meal on the in vitro digestibility of its crude protein for ruminants

The effect of tannin treatment (TSFM) and subsequent urea supplementation (TSFM + U) on the digestibility of sunflower meal (SFM) protein was studied by means of a three-phase laboratory method simulating the ruminant's digestion. Under the influence of the ruminal fluid 67% of SFM protein, 62% of TSFM protein and 58% of TSFM + U protein was degraded. The pepsin and pancreatin digestibilities of rumen undegraded protein (UDP) were as follow: 58.2% (SFM), 56.6% (TSFM), 43.3% (TSFM + U), and 22.0% (SFM), 28.8% (TSFM), 17.5% (TSFM + U), respectively. The four fractions (dissolved protein, oligopeptides, amino acids, and ammonia) of rumen degradable protein (DP) were also determined: 85 to 92% of rumen degradable protein was recovered in these four fractions. Owing to tannic acid treatment the quantity of dissolved protein decreased and that of oligopeptides increased.     

尼龙袋法和改良体外三步法评定瘤胃保护性赖氨酸的瘤胃降解率及小肠消化率

本试验旨在利用尼龙袋法和改良体外三步法评定脂肪粉包被赖氨酸（Lys）的瘤胃降解率及小肠消化率。选用3只安装有永久性瘤胃瘘管的体重为（28.0±2.97）kg的5月龄哈萨克公羊,代谢笼内单笼饲养,每天饲喂棉籽壳200 g、精料500 g、小麦秸400～500 g,余料不超过10%。结果表明,该脂肪粉包被赖氨酸的干物质（DM）及粗蛋白质（CP）在瘤胃内的有效降解率均为20%,瘤胃保护率达到80%。经胃蛋白酶和胰酶培养24 h后,DM及CP的消化率分别达到63.6%和98.8%。综上所述,该脂肪粉包被赖氨酸可作为一种新型有效的反刍动物氨基酸补充形式。     

The effects of high levels of rumen degradable protein on rumen pH and histamine concentrations in dairy cows

An experiment was conducted to test the hypothesis that the supplementation of crude protein (CP) results in rumen acidosis and increased histamine concentrations in dairy cows. Six ruminally fistulated, non-pregnant dry cows were fed three experimental rations in a replicated 3 × 3 Latin square design. The CP contents in the low-CP, the high rumen undegradable protein (high-RUP) and the high rumen degradable protein (high-RDP) rations were 112, 259 and 266 g/kg dry matter (DM) respectively. The cows were fed 7.7 kg DM of the concentrates and 2.7 kg DM of rice straw. High levels of RDP in the ration significantly increased the ammonia, total volatile fatty acid (VFA) and histamine concentrations in the rumen fluid. However, supplemental CP, whether degradable or undegradable, did not significantly affect the pH of rumen fluid. Plasma urea nitrogen concentration was higher in both high-RDP and high-RUP in relation to cows fed the low-CP ration. The rise in ruminal histamine concentrations was physiologically non-relevant, most likely because rumen pH was not affected by supplemental CP at the installed level of DM intake. Therefore, it can be concluded that the issue of supplemental CP, rumen pH and ruminal histamine concentrations has not yet been settled. Further research is warranted to understand these relationships.     

Effect of Fusarium toxin-contaminated triticale and forage-to-concentrate ratio on fermentation and microbial protein synthesis in the rumen

In this study, the effect of Fusarium toxin-contaminated triticale (FUS) at high (60%) and low (30%) concentrate proportion in ruminant rations on ruminal fermentation, microbial protein synthesis and digestibility was investigated, using in vivo and in vitro methods. Significant effects of the forage-to-concentrate ratio on ruminal degradation and digestibility of crude nutrients and detergent fibre fractions as well as on the pH value and the concentration of short chain fatty acids (SCFA) in rumen fluid were found. The production of SCFA was affected, and the degradation of crude fibre and neutral detergent fibre in the rumen was reduced by the inclusion of FUS at high concentrate proportion. The efficiency of microbial crude protein synthesis was higher in diets with 60% than in diets with 30% concentrates, but was impaired in the presence of FUS in vitro at the high concentrate level. Marginal effects of FUS on the amino acid pattern of microbial protein were detected. It was concluded that the use of FUS in high concentrate diets can influence ruminal fermentation and microbial protein synthesis at a dietary deoxynivalenol concentration below 5 mg/kg dry matter.     

In situ ruminal degradability and intestinal digestion of raw and extruded legume seeds and soya bean meal protein

An experiment was performed to evaluate the effect of extrusion and carbohydrate addition on rumen degradation and intestinal digestion of raw legume seeds and solvent extracted soya bean meal (SBM) protein. Whole soya beans (WSB) without or with maize added (75:25) (WSB-M), peas, lupins and SBM were extruded at 140 degrees C. Protein rumen degradation and intestinal digestibility of unprocessed and extruded protein sources were measured by in sacco and mobile bag procedures, respectively, in two dairy cows cannulated in rumen and duodenum. Between 12 and 15 polyester bags with 4 g of each protein source were incubated in rumen for 12 h and the residues, pooled by feed, were introduced into the duodenum in small nylon bags after pre-incubation in a pepsin solution, and recovered from faeces the day after. Extrusion significantly (p < 0.001) reduced N degradation of all protein sources, from 98.1%, 91.6%, 90.5% and 64.8% to 53.1%, 73.8%, 70.3% and 44.2% for peas, lupins, WSB and SBM respectively. The addition of maize to WSB strengthened the effect of extrusion on rumen N degradation, from 88.2% to 52.6%. Residues from rumen incubation of extruded feeds showed a higher (p < 0.001) intestinal N digestibility except for SBM (87.0%, 82.9%, 66.3%, 85.0% and 97.2%, and 99.1%, 95.8%, 96.8%, 97.8% and 98.7%, respectively, for non-extruded and extruded, peas, lupins, WSB, WSB-M and SBM). In conclusion, the extrusion of studied legume seeds and SBM promotes a clear and significant increase of their metabolizable protein value, particularly in peas, and the inclusion of a source of carbohydrates before extrusion increase this response.     

甘露寡糖、果寡糖和大豆寡糖组合对锦江黄牛瘤胃液细菌多样性的影响

本试验旨在研究功能性寡糖(甘露寡糖、果寡糖和大豆寡糖)组合对锦江黄牛的瘤胃液细菌多样性的影响.选择3头健康且体重相近的安装有永久性瘤胃瘘管的锦江黄牛,采用自身对照方法,试验分2期进行,第1期:对照期,饲喂基础饲粮,不添加任何寡糖;第2期:添加期,饲喂基础饲粮+功能性寡糖(0.8％甘露寡糖+1.0％果寡糖+0.8％大豆寡糖),每期持续14 d.利用PCR-变性梯度凝胶电泳(DGGE)方法研究分析牛瘤胃液细菌多样性.结果表明:添加功能性寡糖组合后,牛瘤胃液细菌PCR-DGGE图谱条带数明显增加,3头牛增加了5个共同条带.经测序,其中2个是产琥珀酸丝状杆菌属,3个是未鉴定细菌.饲粮中添加功能性寡糖组合可使瘤胃液细菌菌群种类明显增加.结果提示,饲粮添加功能性寡糖组合能够影响瘤胃菌群区系,增强其稳定性.     

Resistance of feed enzymes to proteolytic inactivation by rumen microorganisms and gastrointestinal proteases.

Potential feed enzyme additives for ruminants were tested in vitro for their stability to ruminal microbial and gastrointestinal proteolysis. Four commercial preparations from Trichoderma longibrachiatum (A, B, C, and D) and one from an undisclosed source (E) were incubated up to 6 h with ruminal fluid taken from four lactating dairy cows before or 2 h after feeding. The stability of preparation B was also tested in the presence of pepsin at pH 3 and pancreatin at pH 7. Cellulase (EC 3.2.1.4), cellulose 1,4-beta-cellobiosidase (EC 3.2.1.91), beta-glucanase (EC 3.2.1.6), xylanase (EC 3.2.1.8), beta-glucosidase (EC 3.2.1.21), and beta-xylosidase (EC 3.2.1.37) activities were monitored throughout the incubations. Polysaccharidase activities of all enzyme preparations were remarkably stable in ruminal fluid taken after feeding. Ruminal fluid obtained before feeding inactivated the polysaccharidases in preparations B and D to a greater extent than ruminal fluid obtained after feeding. Cellulase and cellulose 1,4-beta-cellobiosidase activities were the least stable, declining (P < 0.05) by 35 and 60% for preparations B and D, respectively. Xylanase activity of preparation D decreased (P < 0.05) by up to 30% after 6 h of incubation, whereas beta-glucanase activity was not affected. The ability to degrade exogenous enzymes also differed among cows (P < 0.05). Pepsin and acid (pH 3.0) did not affect polysaccharidases in preparation B but decreased glycosidase activities by 10 to 15% (P < 0.05) after 1 h of incubation. Pancreatin, at the maximum concentration used, inactivated cellulase, cellulose 1,4-beta-cellobiosidase, and xylanase activities at a rate of 0.55, 1, and 0.45%/min, respectively. beta-Glucosidase and beta-xylosidase activities decreased by 1 and 0.75%/min, respectively. Partial proteolysis of cellulase, cellulose 1,4-beta-cellobiosidase, and xylanase by pancreatin produced a transient increase in activity. This twofold increase for cellulase and fourfold increase for cellulose 1,4-beta-cellobiosidase was directly proportional to pancreatin concentration. These results suggest that the enzyme feed additives tested were stable in the rumen of animals after feeding. Exogenous enzymes are likely to be more susceptible to the host gastrointestinal proteases in the abomasum and intestines than to ruminal proteases. However, exogenous polysaccharidases may survive for a considerable period of time in the small intestine and they probably maintain activity against target substrates in this environment.     

Amino acid profile of escaped feed protein after rumen incubation and their intestinal digestibility.

The crude protein content and amino acid profile of seven feedstuffs (linseed meal, maize gluten meal, rapeseed meal, rapeseed meal protected, soybean meal, fullfat soybean extruded and sunflower meal) were determined before and after ruminal incubation for 16 h in three bulls with large rumen cannulas. The intestinal disappearance of amino acids was measured using mobile bag technique. Ruminal incubation affected amino acid profile of all experimental feedstuffs. Crude protein degradation varied from 29.3% for maize gluten meal to 86.4% for rapeseed meal. A tendency towards increased disappearance was observed for glutamic acid, histidine, lysine and proline and decreased disappearance for branched-chain amino acids. The intestinal crude protein digestibility was higher than > 80%, except rapeseed meal (66.4%) and sunflower meal (77.8%). The least digestible individual amino acids were methionine and isoleucine in rapeseed meal, histidine and methionine in rapeseed meal protected and arginine in sunflower meal. In general, the lowest amino acid digestibilities were found in feedstuffs with the highest fibre content. The feedstuffs show that they have different potential for supplying of limiting amino acids. Of particular value are the feedstuffs with low crude protein degradability in the rumen and high intestinal digestibility of amino acids.     

生物纤维饲料对绵羊的饲用价值研究

本试验以绵羊作为研究对象，通过常规养分测定、消化试验和瘤胃降解试验(尼龙袋法)，对生物纤维饲料的常规养分、饲用价值、瘤胃降解特性进行了探讨。结果表明：生物纤维饲料中干物质、粗蛋白、粗脂肪、粗纤维、粗灰分、无氮浸出物、钙和磷的含量分别为：65．61％、21．97％、1．88％、3．00％、7．79％、30．97％、0．85%和1．13％；绵羊对生物纤维饲料的干物质、粗蛋白、粗脂肪、粗纤维、粗灰份、无氮浸出物和能量的消化率分别为74．71％、84．81％、72．24%、72．68％、45．41％、77．52％、77．76％；同时测得生物纤维饲料原样中的消化能为10 100kJ／kg；生物纤维饲料干物质的有效降解率为61．75%，而蛋白质的有效降解率为73．73％。     

甘草提取物对卡拉库尔羊体外瘤胃发酵参数的影响

本试验以3只健康的卡拉库尔羊为瘤胃液供体,采集瘤胃液进行体外发酵培养,试验设计为基础日粮中分别添加不同来源样组:对照组(G0)、10%胀果甘草粗提物组(G1)、10%刺果甘草粗提物组(G2)、10%刚果甘草粗提物(G3)、10%甘草原样(G4);分别添加不同水平甘草提取物组:0%组(Z0)、0.5%组(Z1)、1%组(Z2)、3%组(Z3)、5%组(Z4)、7%组(Z5),研究其对瘤胃发酵参数:pH、挥发性脂肪酸(乙酸、丙酸、丁酸)、产气量、氨态氮浓度(NH₃-N)的影响。结果显示,本试验添加的G1、G2、G3、G4组在一定程度上均可以降低瘤胃产气量和乙酸产量;添加不同剂量的甘草粗提取物时,Z3组的添加剂量使瘤胃pH在正常范围,同时对产气量无显著影响,乙酸/丙酸比值为最低。     

奶牛主要植物性蛋白质饲料蛋白质和纤维物质瘤胃降解率的研究

选用3头安装永久性瘤胃瘘管的健康荷斯坦产奶牛为试验动物,选取8种北方地区奶牛常用蛋白质饲料原料为试验样品,每个样品设3个重复,用尼龙袋法分别测定各个样品的粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)在瘤胃内的动态降解率和有效降解率。结果表明:(1)所选8种蛋白质饲料原料中葵花粕的粗蛋白质(CP)有效降解率均高于其他粗饲料,达到61.17%以上,酒精粕的粗蛋白质(CP)有效降解率最低,仅为19.03%。(2)在饲喂基础上,玉米蛋白粉所含的瘤胃降解蛋白质(RDP)的比例最高,达到30.99%以上,而酒精粕所含的比例最低,仅为5.52%。(3)豆粕所含的中性洗涤纤维(NDF)的有效降解率最高,达到50.74%以上,而菜籽粕的最低,仅为11.06%。(4)玉米蛋白粉所含的酸性洗涤纤维(ADF)的有效降解率最高,达到59.23%以上,而酒精粕的最低,仅为11.27%。     

不同的处理方法对稻草营养价值的影响

分别用尿素、秸秆发酵活干菌、复合酶处理稻草，并检测处理前后营养成份、降解率、感官评定、适口性等指标变化。结果表明，处理后各处理组的CP（粗蛋白质）含量分别比对照组提高10．3％，15．6％及11．8％；CF（粗纤维）含量分别下降4．0％，11．2％和21．8％，其中活干菌发酵对CP稻草含量提高较大，饲用复合酶处理使CF含量下降幅度较大。同时，对各处理组DM（干物质）、NDF（中性洗涤纤维）、ADF(酸性洗涤纤维）的瘤胃降解率测定发现，各处理组DM，NDF及ADF降解率均有一定提高，其中以活干菌发酵处理效果旯好，其DM、NDF及ADF降解率分别达40．90％、33．83％及34．24％。在感官评定、适口性方面，除氨化处理有刺激性气味外，其它两处理组具有较浓的酸香味且家畜喜欢采食。     

单宁酸对生长猪胃-小肠仿生消化中消化酶活性及饲粮粗蛋白消化率的影响

本试验旨在探讨单宁酸对生长猪胃、小肠仿生消化中消化酶活性及玉米-豆粕型饲粮干物质和粗蛋白消化率的影响，为评价单宁酸的生物学效应提供参考。试验一采用单因素完全随机设计，考察在无饲粮下2种单宁酸对猪模拟胃液、模拟小肠液消化酶活性的影响。设5个处理，单宁酸添加量分别为0 mg （胃液体积为20 mL，小肠液体积为22 mL）；单宁酸1，10 mg；单宁酸1，20 mg；单宁酸2，10 mg；单宁酸2，20 mg。测定各处理的胃蛋白酶、淀粉酶、胰蛋白酶和糜蛋白酶的活性。试验二考察玉米-豆粕型饲粮添加单宁酸对猪仿生消化中胃、小肠阶段消化酶活性及养分消化率的影响。采用单因素完全随机设计，设5个处理，单宁酸在饲粮中的含量分别为0 mg·（2 g）^-1；单宁酸1，10 mg·（2 g）^-1；单宁酸1，20 mg·（2 g）^-1；单宁酸2，10 mg·（2 g）^-1；单宁酸2，20 mg·（2 g）^-1。测定仿生消化中胃阶段0.5和4 h时胃蛋白酶活性，小肠阶段0.5、4和8 h时淀粉酶、胰蛋白酶和糜蛋白酶活性及生长猪胃-小肠仿生消化测定饲粮的干物质和粗蛋白消化率。结果表明：1）无饲粮的情况下，和空白对照组相比，2种单宁酸对模拟胃液中胃蛋白酶活性无显著影响（P>0.05），单宁酸1比单宁酸2更高地降低了模拟小肠液中淀粉酶、胰蛋白酶和糜蛋白酶的活性（P<0.05）。2）在饲粮进行仿生消化的胃消化0.5～4 h内，除4 h时10 mg·（2 g）^-1添加量外，添加单宁酸1时胃蛋白酶的活性均显著高于添加单宁酸2时的相应值（P<0.05），除单宁酸2在消化0.5 h外，2种单宁酸在添加10 mg·（2 g）^-1时胃蛋白酶活性均显著高于20 mg·（2 g）^-1添加量的相应值（P<0.05）。在小肠仿生消化0.5 h时，饲粮中添加单宁酸1、2的2个水平对消化液中淀粉酶活性无显著影响（P>0.05），但均显著降低了糜蛋白酶的活性（P<0.05）；单宁酸1的消化液中胰蛋白酶活性高于单宁酸2的相应值（P<0.05）。在小肠仿生消化4 h时，除添加水平为20 mg·（2 g）^-1时的糜蛋白酶活性外，饲粮中添加单宁酸1消化液中淀粉酶、糜蛋白酶活性高于添加单宁酸2的相应值，而胰蛋白酶活性低于添加单宁酸2的相应值（P<0.05）。单宁酸1、2的两个添加量均降低了胰蛋白酶和糜蛋白酶的活性（P<0.05）。在小肠仿生消化8 h时，饲粮中单宁酸的添加量影响了淀粉酶的活性，但单宁酸1和单宁酸2各两个添加量在淀粉酶的平均活性上无显著差异（P>0.05）。单宁酸1、2的两个添加量均降低了胰蛋白酶、糜蛋白酶的活性（P<0.05）。3）与对照组相比，两种单宁酸在两种添加水平下均显著降低了饲料粗蛋白消化率（P<0.05），且单宁酸2比单宁酸1更多地降低了饲粮粗蛋白的消化率（P<0.05）。综上所述，在有、无饲粮条件下，单宁酸对消化酶活性呈现不一致影响。单宁酸影响饲粮粗蛋白的消化率可能主要与消化液中糜蛋白酶活性降低以及单宁酸与饲粮中的化学成分形成螯合物降低了小肠消化酶的水解效率有关。     

In vitro evidence for the importance of cultivation conditions on the effects of Calliandra tannins on ruminal escape of soybean protein and its post‐ruminal degradability

Purified condensed tannins (CT) extracted from the legume Calliandra calothyrsus (var. San Ramón CIAT 22310), harvested in the dry and the rainy season and cultivated with low or high level of fertilization were added to soybean meal in a ratio of 600 mg/g of the incubated crude protein (CP). Effects on degradation either in ruminal fluid only, or in ruminal fluid followed by incubation in HCl/pepsin, were evaluated using a modified two‐step in vitro method. Season was found to have larger effects on in vitro ruminal and post‐ruminal CP degradation than fertilization. Condensed tannins from the rainy season harvest reduced ruminal CP degradation less than that from the dry season harvest. They had also less negative effects on the degradability of rumen escape protein and enhanced the proportion of post‐ruminally degraded CP more than CT from the dry season harvest. An increase in level of fertilization reduced ruminal CP degradation in CT from the rainy season plants but this was not associated with effects on post‐ruminal degradation. The study demonstrated the importance of environmental factors for the efficiency of CT in modifying ruminal and post‐ruminal CP degradation.     

向日葵秆和向日葵盘对绵羊营养价值的评定

试验选用6只体重28 kg左右安装永久瘤胃瘘管的甘肃高山细毛羯羊, 采用3×3无重复拉丁方设计, 通过消化代谢试验, 对向日葵秆和向日葵盘对绵羊的营养价值进行了评定。结果表明:向日葵秆和向日葵盘风干样品中干物质、粗蛋白质、粗脂肪、粗纤维、中性洗涤纤维、酸性洗涤纤维、粗灰分、钙、磷分别为90.73%, 5.72%, 0.89%, 30.15%, 53.09%, 39.40%, 11.61%, 0.84%, 0.13%和89.63%, 11.84%, 2.13%, 12.48%, 23.51%, 15.41%, 14.04%, 0.97%, 0.29%;向日葵秆和向日葵盘对绵羊干物质消化率、氮消化率、氮存留率、有机物消化率、中性洗涤纤维消化率、酸性洗涤纤维消化率、钙消化率、磷消化率及消化能分别为61.61%, 65.37%, 34.72%, 65.19%, 48.18%, 44.89%, 29.10%, 26.07%, 8.75 MJ/kg和70.96%, 69.57%, 41.60%, 76.26%, 60.87%, 58.60%, 37.98%, 44.75%, 9.97 MJ/kg。饲粮中添加向日葵秆对绵羊瘤胃液中乙酸摩尔比及氨氮含量产生了显著的影响(P<0.05),对瘤胃液pH、总挥发性脂肪酸、丙酸摩尔比、丁酸摩尔比、其他酸摩尔比及瘤胃液中总氮、尿素氮、蛋白氮浓度均无显著影响(P>0.05);饲粮中添加向日葵盘对绵羊瘤胃液乙酸摩尔比、丙酸摩尔比和乙酸/丙酸产生了显著的影响(P<0.05),对pH、总挥发性脂肪酸、丁酸摩尔比、其他酸摩尔比和瘤胃液含氮量无显著影响(P>0.05)。     

Effect of some electrolytes on in vitro rumen microbial protein synthesis in buffaloes.

In vitro studies were carried out to examine the effect of MnCl2, MgCl2, CoCl2 and CaCl2 on protein synthesis by rumen microorganisms obtained from fistulated buffalo calves (Bubalus bubalis). The concentration of the electrolytes in stained rumen fluid (SRF) ranged from 1 to 20, 1 to 20, 0.25 to 5 and 1 to 20 mM, respectively. MnCl2 (15 mM), MgCl2 (10 mM), CoCl2 (2.5 mM) and CaCl2 (20 mM) increased the protein content in the incubation mixture (IM) by 501, 230.8, 537.6 and 84% and the per cent incorporation of 35S from (NH4)2 35SO4 into microbial protein by 125.6, 108.5, 113.4 and 40.3, respectively, over the control values, when the incubation lasted 8 h. The NH3-N content in IM decreased by 8, 14, 43 and 16% when 10 mM MnCl2, 20 mM MgCl2, 1 mM CoCl2 and 1 mM CaCl2, respectively, was added and the incubation lasted 6 h. The reasons for increased protein biosynthesis by rumen microorganisms in the presence of the above electrolytes are discussed.     

饲粮蛋白质水平对重庆黑山羊消化代谢的影响

以5月龄左右重庆黑山羊为试验动物,配制了粗蛋白质水平分别为8.23%、10.42%和12.52%的饲粮,进行了消化代谢试验和瘤胃降解试验。结果表明:随着饲粮中粗蛋白质水平的提高,各组间的干物质消化率、粗蛋白质消化率、氮沉积率、中性洗涤纤维消化率、酸性洗涤纤维消化率、粗纤维消化率之间的差异均不显著(P>0.05)。随着饲粮中粗蛋白质水平的提高,瘤胃内中性洗涤纤维的降解率在各个时间点变化不明显(P>0.05);酸性洗涤纤维的降解率在6h及以前降低(P<0.05),之后接近;干物质的降解率在6h及以前提高(P<0.05),之后接近;有机物的降解率在6h提高(P<0.05),之后接近;粗蛋白质降解率在12h及以前提高(P<0.05),之后接近。     

The feeding of ad libitum dietary protein to organic growing-finishing pigs

The effects of three dietary protein levels on growth, meat, and carcass traits were studied in organic pigs fed a three-phase diet. Assuming lysine was the first limiting amino acid, feeds were formulated to ileal digestible (ID) lysine content, with the ID lysine:crude protein ratio set at a constant of 4%. Feeds were also formulated to an isocaloric rate (net energy: 9.4 MJ/kg during the first feeding phase, 9.25 MJ/kg during the second feeding phase and 9.1 MJ/kg during the finisher phase), with a high (HP), a medium (MP) or a low (LP) protein content ranging from 20% to 14% crude protein (CP). ID lysine content of the LP and MP feed was, respectively, 80% and 90% of the ID lysine content of the HP feed. The nutrient formulation of the HP feed was similar to nutrient levels commonly used in conventional Belgian pig farming. From 20 to 40 kg liveweight, the pigs showed better feed conversion ratios, with an increasing dietary protein concentration (r(2)=0.84). This effect was not observed in the second and third phases, although a significant effect of protein concentration on voluntary feed intake in the second phase did occur (P=0.018), probably as a compensation for the lower protein concentration in the LP diet. Analysis of the carcasses showed a lower meat percentage with lower protein concentration (P<0.05), whereas influences on meat quality were limited. It was concluded that whereas during the first phase of growth, higher protein concentration leads to better performance, from the second phase onwards (45 kg), at least with isocaloric diets, a decrease in protein content (corresponding to a 10% reduction in dietary ID lysine levels compared to conventional pig fattening) may be used in organic growing-finishing pig nutrition.     

复合酶制剂对泌乳奶牛瘤胃发酵、营养物质表观消化率及生产性能的影响

本试验旨在研究饲粮中添加不同剂量的复合酶制剂对泌乳奶牛瘤胃发酵、营养物质表观消化率、血清指标及生产性能的影响。选择体重、胎次[(2.30±0.06)胎]、产奶量[(37.00±0.03)kg/d]、泌乳天数[(90±0.15)d]相近的9头泌乳期荷斯坦奶牛,随机分成3组,每组3头。采用3×3拉丁方设计,对照组饲喂基础饲粮,试验组Ⅰ和试验组Ⅱ分别在基础饲粮基础上添加10和20 g/(头·d)的复合酶制剂,进行3期动物试验。每期21 d,其中14 d为预试期,7 d为采样期。结果表明:1)饲粮中添加10 g/(头·d)的复合酶制剂显著提高奶牛瘤胃液中丁酸的浓度(P0.05),而对总挥发性脂肪酸和其他挥发性脂肪酸的浓度无显著影响(P0.05);2)与对照组相比,饲粮中添加10 g/(头·d)的复合酶制剂显著提高奶牛对干物质、粗蛋白质和中性洗涤纤维的表观消化率(P0.05),对酸性洗涤纤维的表观消化率也有一定的提高作用(P=0.06);3)饲粮中添加10和20 g/(头·d)的复合酶制剂显著提高了奶牛的产奶量(P0.05),且10 g/(头·d)组的4%校正乳(4%FCM)产量、乳脂产量和乳糖产量分别较对照组提高4.85(P0.05)、0.49(P0.05)和0.32 kg/d(P0.05);4)复合酶制剂的添加未对奶牛血清指标产生显著影响(P0.05)。综上,饲粮中添加10 g/(头·d)复合酶制剂能够显著提高泌乳奶牛的产奶量、乳脂产量和瘤胃液丁酸浓度,且饲喂效果优于添加量为20 g/(头·d)时。综合考虑,泌乳奶牛饲粮中复合酶制剂的推荐添加量为10 g/(头·d)。