蒸汽爆破技术在玉米秸秆饲料化利用中的研究进展

玉米秸秆是作物残余物中最丰富的木质纤维素生物质之一,主要由纤维素、半纤维素和木质素通过氢键及其他化学键、分子键结合而成,是具有复杂聚合结构的高分子化合物,作为动物饲料的可利用率较低。蒸汽爆破即汽爆,是应用蒸汽弹射原理实现爆炸过程中对生物质预处理的技术。将蒸汽爆破技术应用于玉米秸秆处理,可高效分离纤维素,对玉米秸秆具有明显的解聚作用,有利于提高玉米秸秆的饲料化利用程度。作者介绍了蒸汽爆破工艺原理与参数,综述了蒸汽爆破处理对玉米秸秆纤维结构、化学成分和酶解产糖的影响,以及对玉米秸秆的营养成分消化率和瘤胃微生物附着的影响。已有研究表明,蒸汽爆破可使蒸汽分子渗入植物组织,经过瞬时释放将内能转化为机械能,作用于生物质组织细胞层间,达到原料分解的目的;蒸汽爆破可改变玉米秸秆的纤维结构,降低半纤维素和木质素含量,提高纤维素含量(随着蒸汽爆破的压强和维压时间的增加,半纤维素含量显著降低,而物料含水率的增加会导致纤维素含量升高);蒸汽爆破可提高玉米秸秆体外发酵酶解产糖率,随着蒸汽爆破压强和维压时间的增加,玉米秸秆体外培养酶解还原糖产量增加;蒸汽爆破可使玉米秸秆的体外发酵产气量、产气速率、干物质和酸性洗涤纤维含量显著提高,可提高反刍动物对玉米秸秆的消化利用率,充分利用玉米秸秆的纤维素,提高玉米秸秆的营养价值;蒸汽爆破通过破坏玉米秸秆的表面结构,可促进瘤胃微生物在玉米秸秆上的附着,从而促进玉米秸秆的降解。综上,蒸汽爆破技术处理玉米秸秆可提高其作为饲料的利用率。     

Carrier rate of the c.235G>C mutation in the bovine isoleucyl-tRNA synthetase (IARS) gene of Japanese Black cows at Kagoshima prefecture, Japan,and analysis of the metabolic profiling and reproductive performance of heterozygous cows

Bovine isoleucyl-tRNA synthetase (IARS) disorder, a major cause of weak calf syndrome, is caused by a homozygous missense (c.235G>C) mutation in the bovine IARS gene of Japanese Black (JB) cattle, which was identified in 2013. However, the extent to which the carrier rate has changed at Kagoshima prefecture, Japan, and whether the carrier status is associated with any clinical or reproductive problems, have yet to be ascertained. In this study, using a real-time polymerase chain reaction-based genotyping assay, we determined the carrier rate in a regional JB cow population at Kagoshima prefecture. Comparative analyses were performed on the metabolic profile test (MPT) results and reproductive performance data obtained for heterozygous carrier and homozygous wild-type cows. In 2009 and 2018, DNA samples were collected from 130 and 462 clinically healthy JB cows, respectively, in Kagoshima prefecture. MPT results and reproductive performance data were evaluated for 62 cows, comprising four heterozygous carriers and 58 wild-type cows. Genotyping revealed that the carrier rate was 6.9% in 2009 and 1.5% in 2018, the difference of which was statistically significant (P<0.005). There were no statistically significant differences between the carrier and wild-type cows with respect to either MPT results or reproductive performance, indicating that the carrier cows have necessary IARS activity to maintain minimal health and reproductive potential.     

施用有机肥对当归药材性状、产量及抗病性的影响

为了探寻有机肥对当归成药栽培的影响,采用黑膜覆盖栽培,基施纯有机肥(O,2000 kg·hm-2)、纯化肥(C,磷酸二铵,420 kg·hm-2)、减半量化肥增施有机肥[1/2(O+C)],以不施肥为对照(CK),栽培期测定早期抽薹率、发病率、药材产量和性状指标.结果表明,纯有机肥栽培当归早期抽薹率为8.0％,分别较C...     

杂交狗牙根诱变后代综合评价

辐射育种是一种获得优良品种的快速有效的植物育种方法。本试验采用9000和11300 rads的⁶⁰Co-γ射线,对8份杂交狗牙根(Cynodon dactylon×C.transvaalensis)的匍匐茎和根状茎进行辐射诱变,从坪用价值、抗寒性和生长速度3个方面对亲本及21个后代进行综合分析与评价,以选育出坪用价值高、生长速度快且抗寒性强的优良狗牙根新种质。结果显示:诱变使狗牙根的坪用性状发生了丰富的不定向的变异,同一亲本通过诱变既可以产生良性变异,也可以产生劣性变异;综合评价结果选育出坪用价值优良的诱变后代3份,分别为C75104M2-1/1,C75502M1和C75103M1-1,其抗寒性半致死温度分别为-0.51,-3.54和-3.67℃,其中C75502M1为坪用价值高且生长速度快的优良诱变后代。     

棘胸蛙产卵量、卵子孵化率的比较研究

为选择适于闽北的棘胸蛙养殖品种,比较了异地引种棘胸蛙和本地引种棘胸蛙的产卵量和卵子孵化率。试验表明,异地经过几个世代驯化的棘胸蛙在总产卵量上要比本地引种的棘胸蛙要多两倍多,产卵总数为3071枚,本地引种的棘胸蛙产卵总数为863枚。异地引种棘胸蛙在卵子孵化率上也比本地引种棘胸蛙要高,平均为95.3%,而本地引种的棘胸蛙的卵子孵化率仅为64.18%,说明异地引种的棘胸蛙在闽北有较好的推广前景。     

不同施肥时期及施肥量对草地早熟禾生长发育特性的影响

研究了不同施肥时期及施肥量对草地早熟禾生长发育特性的影响。研究表明：返青期加强施肥有利于草地早熟禾的生长,同时,可显著提高植株密度以及千物质的积累量。     

Effect of banding or burdizzo castration on plasma testosterone, acute-phase proteins, scrotal circumference, growth, and health of bulls

The objective was to assess the effect of banding or burdizzo castration performed on farms on plasma testosterone, acute-phase proteins, scrotal circumferences, growth, and well-being of bulls. 243 Continental bulls (12 months; 399.2 ± 5.72 kg) from three different farms were allocated at random, after stratification on weight within breed type, to one of three treatment groups: banding castration (BAND; n = 80), burdizzo castration (BURD; n = 83), or controls (CON; n = 80). The castration methods were conducted under local anaesthesia, and tetanus toxoid vaccine and antibiotic were also injected at castration. BAND and BURD castrates had lower (P < 0.001) plasma testosterone concentration than control bulls, with no difference between BAND and BURD castrates on 28 d post-castration. From days 0 to 14 post-castration, BAND (P = 0.0002) and BURD (P < 0.0001) castrates had lower average daily gain (ADG) than CON bulls, no difference (P = 0.46) was found between BAND and BURD castrates. From days 15 to 28, BAND castrates had lower ADG compared with BURD castrates (P = 0.03) and CON bulls (P = 0.01), while no difference (P = 0.76) was found between BURD and CON. From days 29 to 56, BAND (P = 0.01) and BURD (P = 0.002) castrates had lower ADG than CON bulls, no difference (P = 0.55) was found between BAND and BURD. From days 57 to 84, the ADG of BAND castrates was not different compared with BURD castrates (P = 0.12) and CON bulls (P = 0.38), while BURD had lower (P = 0.02) ADG compared with CON. The integrated ADG from day 0 to 112 of BAND (P = 0.0001) and BURD (P = 0.02) groups were lower compared with CON, while there was no difference (P = 0.09) between BAND and BURD castrates. On d 14 post-castration, BAND castrates had lower scrotal temperature than BURD (P < 0.0001) and CON (P < 0.0001), and BURD castrates had greater (P < 0.006) scrotal temperature than CON; BAND castrates had lower scrotal latitudinal and longitudinal circumferences than BURD castrates (P < 0.001) and CON bulls (P < 0.001), and BURD castrates had greater (P < 0.001) scrotal latitudinal and longitudinal circumferences than CON bulls. BAND (P < 0.0001) and BURD (P = 0.01) castrates had greater glucose concentration than CON bulls, and BAND castrates had greater (P = 0.04) glucose concentration than BURD. In conclusion, BAND or BURD castration significantly reduced plasma testosterone concentration; reduced average daily weight gain mainly during the first 2 weeks, which was not compensated during the subsequent 16 weeks; increased withdrawal of stored energy and increased plasma protein concentration. BURD showed an advantage over BAND in growth during days 15 to 28 following castration.     

Effects of a low dose infusion of racemic and S-ketamine on the nociceptive withdrawal reflex in standing ponies

ObjectiveTo investigate the effect of plasma concentrations obtained by a low dose constant rate infusion (CRI) of racemic ketamine or S-ketamine on the nociceptive withdrawal reflex (NWR) in standing ponies.Study designProspective, blinded, cross-over study.AnimalsSix healthy 5-year-old Shetland ponies.MethodsPonies received either 0.6 mg kg⁻¹ racemic ketamine (group RS) or 0.3 mg kg⁻¹ S-ketamine (group S) intravenously (IV), followed by a CRI of 20 μg kg⁻¹minute⁻¹ racemic ketamine (group RS) or 10 μg kg⁻¹minute⁻¹ S-ketamine (group S) for 59 minutes. The NWR was evoked by transcutaneous electrical stimulation of a peripheral nerve before drug administration, 15 and 45 minutes after the start of the bolus injection and 15 minutes after the end of the CRI. Electromyographic responses were recorded and analysed. Arterial blood was collected before stimulation and plasma concentrations of ketamine and norketamine were measured enantioselectively using capillary electrophoresis. Ponies were video recorded and monitored to assess drug effects on behaviour, heart rate (HR), mean arterial blood pressure (MAP) and respiratory rate.ResultsThe NWR was significantly depressed in group RS at plasma concentrations between 20 and 25 ng mL⁻¹ of each enantiomer. In group S, no significant NWR depression could be observed; plasma concentrations of S-ketamine (9–15 ng mL⁻¹) were lower, compared to S-ketamine concentrations in group RS, although this difference was not statistically significant. Minor changes in behaviour, HR and MAP only occurred within the first 5–10 minutes after bolus drug administration in both groups.ConclusionAntinociceptive activity in standing ponies, demonstrated as a depression of the NWR, could only be detected after treatment with racemic ketamine. S-ketamine may have lacked this effect as a result of lower plasma concentrations, a more rapid metabolism or a lower potency of S-ketamine in Equidae so further investigation is necessary.     

A Single Sample Method for Evaluating 51Chromium-Ethylene Diaminic Tetraacetic Acid Clearance in Normal and Hyperthyroid Cats

Background: Chronic kidney failure is frequently seen in middle-aged and elderly cats. ⁵¹Chromium-ethylene diaminic tetraacetic acid (⁵¹Cr-EDTA) clearance and single blood sample (SBS) method are used in several species to estimate the glomerular filtration rate (GFR).
Hypothesis: The hypothesis of this study was that ⁵¹Cr-EDTA clearance could be determined using an SBS method in normal and hyperthyroid cats.
Animals: Forty-six cats were included in this study, with an average age of 9.5 years. Of these cats, 27 had hyperthyroidism; 19 were healthy.
Methods: After IV injection of ⁵¹Cr-EDTA (average dose: 4.25 MBq), 7 blood samples were obtained between 5 and 240 minutes. Reference clearance was calculated in mL/min and mL/min/kg body weight, using a 2-compartment model. Optimal time for clearance measurement with SBS was then determined by systematically comparing each individual plasma concentration to the reference multisample clearance.
Results: The average reference plasma clearance of ⁵¹Cr-EDTA for all cats was 14.9 mL/min (3.7 mL/min/kg). The clearance in hyperthyroid cats averaged 16.4 mL/min (4.3 mL/min/kg) and in normal cats averaged 10.3 mL/min (2.4 mL/min/kg).
The optimal time for the SBS was 48 minutes after injection of tracer ⁵¹Cr-EDTA ( R ²= 0.9414), giving the following converting equation: clearance = (0.0066 × DV_{48 minutes}) – 0.9277 (in mL/min).
Conclusions and Clinical Importance: In this study, the single sample ⁵¹Cr-EDTA clearance method was used to estimate the global GFR in cats. The method identified differences in clearance between normal and hyperthyroid cats. The optimal time for an SBS was 48 minutes.     

Short-term transportation in a small vehicle affects the physiological state and subsequent water consumption in goats

We investigated the physiological effects on goats of transportation for one hour in a small truck. We also investigated food and water consumption after transportation. Eight adult goats (four castrated males and four ovariectomized females) were used. Plasma levels of cortisol, glucose and free fatty acids increased significantly within 15 min of the start of transportation, and these higher levels were maintained throughout transportation. These results indicate that transportation in a small truck activates the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system in goats. Despite activation of the sympathetic nervous system, heart rate (HR) in subjected animals during transportation did not differ from during the control animals, which were housed in their usual pen. However, after the transportation had ended and the goats started to eat fodder, HR increased significantly. There was no difference in the amount of food consumption between the control and transported goats. Water consumption in the first three hours after transportation was significantly lower in the transported goats than in the controls for the equivalent period. In the subsequent three hours, however, the transported goats consumed more water than the controls. Consequently, the total water consumption of the transported goats did not differ from that of the controls during the six hours after transportation. In conclusion, short-term transportation with a small vehicle activated the HPA axis and the sympathetic nervous system in goats. HR was not increased during transportation, but after the transportation had ended HR in transported goats was higher than that in control goats. After transportation, goats had consumed the same amount of food as control goats, but water consumption during three hours after the transportation was lower than that of control goats.