Utilization of nutrients as influenced by different restriction levels of feed intake under sub-tropical conditions in crossbred calves

Twenty growing crossbred calves (mean body wt. 159.7 ± 3.94 kg) were randomly divided into 4 groups 5 in each following randomized block design. To assess the voluntary dry matter intake (VDMI) during preliminary feeding period, all the animals were fed concentrate mixture and wheat straw ad libitum. The lowest DMI amongst all animals fed ad libitum was defined as ‘VDMI’. The animals were fed at four fixed levels. The highest level of DMI was 95% of VDMI (group 1) as determined in preliminary period of feeding the other 3 levels were 80% (group 2), 60% (group 3) and 40% (group 4) of the VDMI. The experimental feeding was continued for a month followed by a metabolism trial. The dry matter intake through concentrate (crushed maize 33, deoiled-soya meal 32, wheat bran 32, mineral mixture 2 and common salt 1 part) and roughage (wheat straw) was 40:60. The DMI (kg/d) and percent of body weight ranged from 1.62 (group 4) to 4.06 (group 1) and 1.20 to 2.58, respectively. The CP intake (g/d) varied from 177 to 442 among 4 groups. The intake of DM, OM, CP, EE, NDF, ADF and hemi-cellulose (g/d or g/kg w^0.75) was also significantly (P < 0.05) different among 4 groups. The digestibility of DM in groups 1, 2, 3 and 4 was 59.9, 61.7, 64.6 and 30.4%, respectively and was significantly (P < 0.05) lower in group 4 as compared to the remaining 3 groups. The digestibility of other all nutrients viz. OM, CP, EE, NDF, ADF and HC was comparable among groups 1, 2 and 3. However, the digestibility of these nutrients was significantly (P < 0.05) lower in group 4 (40% intake) as compared to the other 3 groups. Intake and balance of N was significantly (P < 0.01) different among 4 groups, being the lowest in group 4. Animals of groups 1, 2 and 3 were in positive nitrogen balance, however, animals of group 4 were in negative N balance. The results revealed that nutrient utilization was unaffected up to 60% level but it was drastically reduced at 40% level of feed intake. It was also observed that calves maintained on 80 and 60% of feed intake lost body weight (250–300 g/d).     

不同处理方法提高反刍动物对粗饲料纤维消化力的机理研究

由于哺乳动物消化腺分泌的淀粉酶不能作用于纤维β-1,4-糖苷键,因此其本身不能直接利用纤维,加之细胞壁结构独特性,这是限制纤维消化的根本原因。真菌和细菌能分泌纤维素分解酶,故在动物消化道内共生的微生物中有许多纤维素酶可以起作用。在保障反刍动物体质和生产性能不下降的情况下,运用科学、合理的处理方法增加反刍动物饲料日粮中纤维消化率是有效降低畜牧养殖业生产成本,充分利用粗饲料资源的有效途径。     

半胱胺对绵羊消化代谢的影响

十二指肠灌注半胱胺后，４头湖羊平均日采食量（以ＤＭ计）虽无显著性变化，而由复胃进入十二指肠的食糜流量则增加１５．８１％（Ｐ〈０．０５）；食糜ＴＮ流量由１８．３４±０．４２ｇ／ｄ提高到２１．３４±０．５８ｇ／ｄ（Ｐ〈０．０１），其中ＭＣＰ－Ｎ及表观过瘤胃蛋白氮（ＢＰＮ）分别提高２８．５７％（Ｐ〈０．０５）和１４．４４％（Ｐ〈０．０５）。瘤胃液总脱氢酶活力平均提高２１．１５％（Ｐ〈０．０２５），ＮＨ３     

不同日粮养分在绵羊体内消化量的研究

用装有永久性瘤胃、十二指肠和回肠瘘管羊测定蛋白质含量为 13 63 %、14 67%和 16 96%三个水平日粮在胃肠道各部位的食糜流通量和消失率。结果表明 :蛋白质含量多的日粮消化率高。瘤胃中干物质消化量比小肠高     

鸡盲肠对饲料磷的消化作用

本文采用去盲肠和有盲肠公鸡的对比试验方法研究了盲肠对饲料磷的消化作用。结果表明：（１）去盲肠鸡内源磷排泄量为４９ｍｇ／日．只,有盲肠鸡的内源磷排泄量为４２ｍｇ／日．只,两者差异极显著（Ｐ〈０．０１）,可见,盲肠能够消化吸收内源磷;（２）当公鸡采食含豆粕、棉仁粕、菜籽粕、花生粕或胡麻粕的半纯合日粮时,植酸磷采食量较高,有盲肠鸡磷的排泄量显著低于去盲肠鸡,真消化率显著高于去盲肠鸡（Ｐ〈０．０５）,表明     

限制性内切酶在PCR缓冲液中酶切活性的研究(英文)

选取6 种常用的限制性内切酶(Acc I、Ban II、EcoR I、Hind III、Sac I、Sca I)用于检测其直接在PCR 缓冲液中完全酶切DNA 的活性。结果表明:在PCR 缓冲液中,需要加入MgCl2作为激活因子的前提条件下,除了EcoR I 表现出星状活性外,其他酶均能完全酶切无甲基化λDNA,其结果与在酶生产厂商推荐的反应缓冲液中进行的酶切反应结果一致;在完成PCR 扩增的PCR 缓冲液中,所有酶(包括RcoR I)均能功能正常地对PCR 产物完全酶切,表明可在PCR 扩增完毕后的反应体系中直接加入限制性内切酶进行酶切反应,无需对PCR 产物进行预先纯化;镁离子浓度在2.5 mmol·L-1至10 mmol·L-1范围内对PCR 缓冲液中的限制性内切酶的活性无显著影响。上述方法可用于限制性片段长度多态(RFLP)以及单链构像多态(SSCP)研究中,但能否用于分子克隆有待进一步实验。图3 表1 参7。     

原子荧光光度法中湿法消解、微波消解前处理法测定土壤中总汞、总砷的比较

采用微波消解对土壤样品进行前处理,同时与湿法消解作比较,采用AFS-930型双道原子荧光光度计测定2种土壤标准物质中总砷、总汞的含量。对2种前处理方法所得的待测液进行5个平行测定,测定值均在其证书标准值范围内,微波消解样品前处理所得的测定结果比湿法消解的更令人满意。     

畜禽饲粮淀粉消化与代谢机制研究进展

淀粉是畜禽能量的主要来源。研究动物体内淀粉消化及其相关的代谢机制对养殖生产实践有着相当重要的意义。因此,阐述了淀粉的特性、结构特征及其组成、加工处理方式对畜禽淀粉消化率的影响,并简要综述了淀粉消化对机体血糖水平和肝脏糖脂代谢的影响。     

不同精料水平对新疆驴利用稻草日粮的影响

本实验选用3头雄性健康新疆驴为实验动物,体重132±10Kg,3～4周岁,采用全收粪消化实验方法,分三期进行,研究在3种精料水平（0g／d、400g／d、800g／d）下新疆驴对稻草日粮的利用率。实验结果表明：400g精料组的干物质采食量为3813±284g／d,较0g精料组的3015±265g／d有显著提高（P〈0．01）,较800g精料组3490±238g／d有显著提高（P〈0．05）,干物质消化率随着精料水平的增加有增加趋势（P〉0．05）。400g和800g精料组的粗蛋白采食量、消化率分别为281±50g／d、53．5±5．7％和357±55g／d、59．2±2．2％,都分别显著高于0g精料组的149±42g／d采食量和36．3士3．8％的消化率（P〈0．01）。400g精料组NDF和ADF的采食量都较其它两组有所提高（P〈O．05）,而三组间的消化率无明显差异（P〉0．05）。800g料组磷的采食量、消化率和能量的消化率分别为8．1±2．8g／d、30．8±4．8％和53．5±3．5％,分别较0g精料组有显著提高（P〈O．05）,与400g精料组间无明显差异（P〉0．05）。新疆驴在日喂400g精料下能够较好的利用稻草日粮。     

酒精废液高温厌氧消化装置比较试验研究

：本文报道了用ＵＡＳＢ／ＩＴＳ、ＵＢＦ和ＵＡＳＢ三种厌氧装置进行实验室规模玉米酒精废液高温厌氧消化比较试验的研究结果。结果表明：三种装置都具有良好的高温厌氧消化处理酒精废液的能力,当有机负荷为１０ｇＣＯＤ／（Ｌ·ｄ）时,它们的ＣＯＤ去除率可以达到９０％,此时的装置产气率为６Ｌ／（Ｌ·ｄ）。综合比较试验结果,ＵＡＳＢ／ＩＴＳ试验装置的运行稳定性最好。