非洲猪瘟在我国爆发，给我国养殖业带来巨大的经济损失，目前无可用的商业化疫苗和药物，其相关研究限定于在高等级生物安全实验室中完成，生物安全防护中消毒剂的合理使用尤为重要。MICRO-CHEM PLUS（MCP）作为一种复合型季铵盐类消毒剂在高等级生物安全实验室广泛使用，而针对非洲猪瘟病毒（African swine fever Virus，ASFV）的灭活效果未见相关报道。本文我们探究不同病毒载量、不同消毒剂浓度、不同作用时间及不同作用温度对于灭活非洲猪瘟病毒效果的影响。研究结果表明高病毒载量需要更高浓度的MCP才能将ASFV完全灭活，较低浓度的MCP需要延长作用时间才能达到完全灭活ASFV的效果，不同的作用温度对于MCP灭活ASFV的效果无影响。应用干雾消毒机将5%MCP进行房间喷雾消毒，当浓度达到0.06L/m3，用ASFV、大肠杆菌和金色葡萄球菌作为生物指示剂，可以达到终末消毒效果，但对于枯草芽孢杆菌作为生物指示剂还有部分活菌残留；当浓度为0.03L/m3时，对于大肠杆菌或金黄色葡萄球菌作为生物指示剂，也可以达到了终末消毒效果。该研究为在特定环境中合理使用 MCP 提供了科学依据，可以用于操作ASFV的高等级生物安全实验室的消毒以及猪场非洲猪瘟感染的预防。

本研究以表达eGFP重组非洲猪瘟病毒为指示病毒，通过体外细胞培养方法，模拟浸泡和喷雾方式，在室温条件下，观察消毒剂不同浓度、不同时间作用后是否产生可见荧光信号为标准，来判定病毒是否完全被消毒剂灭活。结果显示，模拟浸泡消毒方式，在室温条件下，碘酸混合溶液0.5%浓度，作用10分钟能完全灭活非洲猪瘟病毒；过硫酸氢钾复合粉0.25%浓度作用30分钟能完全灭活非洲猪瘟病毒；枸橼酸粉0.25%浓度作用30分钟能完全灭活非洲猪瘟病毒；二氯异氰脲酸钠粉0.125%浓度作用60分钟能完全灭活非洲猪瘟病毒；戊二醛癸甲溴铵溶液0.2%浓度作用60分钟能完全灭活非洲猪瘟病毒；癸甲溴铵溶液0.5%浓度作用60分钟能完全灭活非洲猪瘟病毒。模拟喷雾消毒方式，在室温条件下，碘酸混合溶液0.5%浓度，作用10分钟能完全灭活非洲猪瘟病毒；过硫酸氢钾复合粉0.25%浓度作用60分钟能完全灭活非洲猪瘟病毒；枸橼酸粉0.5%浓度作用30分钟能完全灭活非洲猪瘟病毒；二氯异氰脲酸钠粉0.25%浓度作用60分钟能完全灭活非洲猪瘟病毒；戊二醛癸甲溴铵溶液0.2%浓度作用60分钟能完全灭活非洲猪瘟病毒；癸甲溴铵溶液0.5%浓度作用60分钟能完全灭活非洲猪瘟病毒。这些结果表明，常用市售6种消毒剂，在实验室条件下，不同浓度和作用时间均能有效灭活非洲猪瘟病毒，本实验建立了一种应用表达eGFP重组非洲猪瘟病毒为指示病毒，快速准确评价消毒剂灭活非洲猪瘟病毒效果的方法，为非洲猪瘟的生物安全防控提供有力理论依据和技术支持。

Two feeding patterns of the segregated weaning or grazing in the pasture are carried out worldwide in animal production. To investigate the difference of growth performance and rumen microorganism population related to methane metabolism in the two feeding patterns, three groups of lambs (70 in total) were used: Weaning at 21 days old and being subjected to high-concentration diets (3WK group with 20 lambs), weaning at 35 days old and being subjected to high-concentration diets (5WK group with 20 lambs), or grazing at pasture with the nursing mother (Grazing group with 30 lambs). The growth performance, pH value of rumen content, and the rumen microbes were investigated during weaning period and fattening period with approximately 3 months. Our results showed that lambs in 3WK and 5WK groups demonstrated a better growth performance than the lambs in Grazing group, but no significant difference was observed in the pH value between the three groups (P>0.05). The total rumen bacterial population of the Grazing lambs was significantly lower than that of 3WK lambs (P<0.05) and 5WK lambs (P<0.05); however, the population of methanogens was 4.2- and 2.7-fold lower in the 3wk (P<0.05) and 5wk (P<0.05) lambs compared with Grazing lambs, respectively; protozoa were also 3.5- and 3.4-fold lower in the 3WK (P<0.05) and 5WK (P<0.05) lambs, respectively. The results revealed that segregated weaning lambs may have better growth performance, and reduce methane-producing microbes.

A comparative slaughter trial was conducted to determine the net mineral requirements for maintenance and growth of Dorper crossbred female lambs raised from 20 to 35 kg of body weight (BW). Thirty-five Dorper×thin-tailed Han crossbred female lambs of (20.3±1.14) kg BW were used: 7 lambs were randomly chosen and slaughtered at the beginning of the experiment as the baseline group for measuring the initial body composition; another 7 lambs were randomly chosen and offered a pelleted mixed diet ad libitum and slaughtered at (27.0±0.73) kg BW; the remaining 21 lambs were randomly divided into 3 groups of 7 animals each and subjected to the same diet either ad libitum or at 70 or 40% of ad libitum intake. The 21 lambs were fed in 7 slaughter groups, with each group consisting of one lamb from each treatment (ad libitum, 70 or 40% of ad libitum intake). The 3 groups were slaughtered when the sheep fed ad libitum attained (33.8±0.52) kg of BW. The body composition of five minerals (Ca, P, Na, K, and Mg) was determined. The net mineral requirements for maintenance were 35.01, 25.18, 9.30, 31.35, and 2.03 mg kg–1 empty BW (EBW) for Ca, P, Na, K, and Mg, respectively, and the net growth requirement per kg of EBW gain ranged from 9.73 to 8.87 g of Ca, 5.83 to 5.27 g of P, 1.73 to 1.63 g of Na, 3.73 to 4.08 g of K, and 0.26 to 0.25 g of Mg for Dorper crossbred lambs in China, respectively. The estimates of mineral requirements with Dorper crossbred lambs in the current study were not consistent with the recommendations from previous studies.

This experiment was conducted to investigate the energy requirement of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation. Fifteen ewes after parturition were randomly assigned to three treatments: ad libitum (100%) feed intake and 80 or 60% ad libitum intake, and another nine non-pregnant ewes were assigned to a blank control group. Digestibility trials were performed in the non-pregnant ewes and in the lactating ewes on the 20th, 50th, and 80th d of lactation. In parallel with the digestibility trial, a respirometry experiment was conducted to determine the methane and carbon dioxide production with an open-circuit respirometry system that was equipped with respiratory chambers. The net energy (NE) and metabolizable energy (ME) requirements for maintenance and growth were calculated using the carbon and nitrogen balance method. The results revealed that the carbon (C) and nitrogen (N) excretions and energy losses at faeces and urine, as well as the output of methane and CO2, increased significantly with decreasing feed intake (P<0.01). The apparent digestibilities of C in the stages of non-pregnancy and early, middle and late lactation were 55.8–58.3%, 62.5–73.8%, 64.8– 71.3%, and 61.7–65.0%, respectively, and the apparent digestibilities of N were 45.2–51.3%, 73.7–82.7%, 72.8–80.5%, and 73.6–76.5%, respectively. The corresponding energy apparent digestibilities were 52.0–56.3%, 60.7–76.6%, 61.0–68.8%, and 61.4–67.7%, respectively. The ME/DE (digestible energy) values were 79.5–85.9%, 79.4–83.5%, 81.0%–85.3% and 78.6–82.9%, respectively. The maintenance requirements of NE, ME, and the efficiencies of ME utilisation for maintenance during the stages of non-pregnancy and early, middle and late lactation were 215.5, 253.1, 247.7, and 244.7 kJ kg–1 BW0.75 d, and 372.4, 327.1, 320.9, and 362.0 kJ kg–1 BW0.75 d, and 0.58, 0.77, 0.77, and 0.68, respectively. The ME requirement for the growth of non-pregnant ewes was 31.3 MJ kg–1 BW gain.

A comparative slaughter trial and a metabolism trial were conducted to determine the requirement of net energy (NE) and metabolizable energy (ME) by the crossbreed of German Mutton Merino×Inner Mongolia Merino for fattening from 35 to 50 kg of body weight (BW). 49 crossbred female lambs ((33.9±2.3) (SD) kg BW) of German Mutton Merino×Inner Mongolia Merino were used. 34 lambs were randomly chosen for comparative slaughter, which were offered an identical mixture diet (concentrate:roughage=55:45) at 100, 75 or 55% of ad libitum intake, whereas the remainders were used in the metabolism trial to evaluate the ME of the diet after methane production was measured by open-circuit respirometry. As feed intake decreased from 100 to 75 and 55% of ad libitum intake, the apparent digestibility of dry matter (DM) linearly increased (P=0.010) from 60.8 to 63.6 and 66.9%, respectively, and methane production decreased from 52.1 to 44.3 and 39.9 L d-1, respectively, but the ratio of methane energy to gross energy intake increased linearly (P=0.010) from 8.20 to 8.96 and 10.97%, respectively. Consequently, the ME values of the diet increased from 9.35 to 9.64 and 9.85 MJ kg-1 DM, respectively. The NE requirement for maintenance (NEm) was 255 kJ kg-1 BW0.75, and the ME requirement for maintenance (MEm) was 352 kJ kg-1 BW0.75, with a partial energy efficiency for maintenance (km) of 0.72. The NE requirement for growth (NEg) ranged from 1.26 to 4.66 MJ d-1 as average daily gains increased from 100 to 300 g d-1, with a partial energy efficiency for growth (kg) of 0.45. These results indicated that the NEg required by crossbred female lambs of German Mutton Merino×Inner Mongolia Merino was lower than the recommendation of the American or British nutritional system.