腹水症对肉鸡生产性能、能量及营养物质利用的影响

选1日龄艾维茵肉鸡120只,随机分为2个处理,每个处理6个重复,每个重复10只鸡,研究低温(LAT)和日粮中添加三碘甲状原氨酸(T3,1.5 mg/kg)诱导肉鸡腹水症(AS)时对肉鸡生产性能、能量及营养物质利用率的影响。结果表明:诱导肉鸡AS发病率和死亡率分别高达66.7%和23.3%;能显著降低肉鸡的生产性能(P<0.05),提高心脏指数(P<0.05);第2周时试验组肉鸡对能量和粗脂肪的利用率极显著低于对照组(P<0.01),粗蛋白显著低于对照组(P<0.05),多数氨基酸也极显著低于对照组,精氨酸却高于对照组;第3周时除蛋白外,其他的营养物质和能量都不同程度地低于对照组,而精氨酸差异不显著(P>0.05)。当肉鸡AS发病率高时,降低肉鸡的生产性能,使肉鸡对饲料能量及粗蛋白、粗脂肪、氨基酸(除Arg外)的利用率降低。     

Effects of EGF or bFGF on the development of porcine parthenogenetic embryos in vitro

Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) were added into the culture medium in different culturing stages. The effects of EGF or bFGF on the development of porcine parthenogenetic embryos were studied in vitro. The results were as follows: The addition of EGF significantly enhanced the cleavage rate of porcine parthenogenetic embryos (P < 0.05). The addition of EGF or bFGF also significantly enhanced the rate of blastocysts formation of 2–4-cell porcine parthenogenetic embryos (P < 0.05). Additionally, the group of bFGF had more numbers of blastocysts and higher rates of blastocysts formation than the groups of EGF and the control. In conclusion, EGF and bFGF were found propitious to the development of porcine parthenogenetic embryos in vitro, and bFGF increased the quality of blastocysts by increasing the total cell number in porcine parthenogenetic embryos. __________ Translated from Acta Veterinaria et Zootechnica Sinica, 2007, 38(1): 36–39 [译自: 畜牧兽医学报]     

鸡源复合益生菌对肉仔鸡免疫球蛋白及Toll样受体通路的影响

目的 探究益生菌对肉仔鸡血清免疫球蛋白与肠道Toll样受体通路的影响。方法 选择90只1日龄白羽肉杂鸡,随机分为3组,即对照组、益生菌低剂量组和益生菌高剂量组。其中对照组饲喂基础日粮,益生菌低剂量组在每千克基础日粮中添加复合益生菌10⁹ cfu,益生菌高剂量组在每千克基础日粮中添加复合益生菌2×10⁹ cfu。第21天,每组随机选取10只鸡放血致死,并立即采集样本,进行ELISA、免疫组化、qPCR及Western blot检测。结果 在第21天,益生菌低剂量组和益生菌高剂量组鸡的料肉比分别比对照组降低9%和12% (P<0.05),血清IgG含量分别升高28%和40% (P<0.01),血清IgM含量分别升高44%和58% (P<0.01)。益生菌低剂量组TLR4蛋白表达和mRNA相对表达量比对照组分别升高33%和28%,AP-1蛋白表达和mRNA相对表达量分别比对照组升高106%和67% (P<0.01);益生菌高剂量组TLR4蛋白表达及mRNA相对表达量比对照组分别升高106%和69%,AP-1蛋白表达及mRNA相对表达量比对照组分别升高163%和98% (P<0.01)。结论 饲喂益生菌可降低肉仔鸡料肉比,提高血清中IgG、IgM的含量,并且通过调节Toll样受体通路蛋白表达可以提高机体免疫力。     

Effect of breed, sex and birth parity on growth, carcass and meat quality in pigs

The effects of breed, sex and birth parity on the traits of growth, carcass and meat quality were investigated in three different breeds including Swedish Landrace, British Large White and an indigenous Chinese breed — Tongcheng pigs. The results indicated that the Swedish Landrace and the British Large White had advantages over the Tongcheng pigs in growth rate, feed conversion rate (FCR) and carcass traits, but had disadvantages in meat quality. In contrast to the British Large White, the Swedish Landrace had higher average daily gain during the trial (ADG2) (877.04 g·day⁻¹ vs. 813.95 g·day⁻¹, P < 0.05), and marbling score (MS) (2.48 vs. 2.02, P < 0.01), larger eye muscle area (EMA) (41.80 cm² vs. 35.14 cm, P < 0.01) and more efficient feed conversion rate (FCR) (3.06 vs. 3.29, P < 0.05), lower muscle shear force (MSF) (4.20 kgf (1 kgf = 9.80665 N) vs. 4.93 kgf, P < 0.05) and backfat thickness (BF) (all P < 0.01) including live backfat thickness (LBF), average backfat thickness at 3 points in the carcass (ABF), backfat thickness between 6th and 7th ribs (6–7 th BF) and backfat thickness at 10th rib (10 th BF). There was a difference (P < 0.05) only inMS between castrated females (CF) and castrated males (CM). Birth parity affected ADG2 (P < 0.05), some carcass characteristics and meat quality, including CL₁ (P < 0.001), CL₂ (P < 0.05), BF (ABF, 6–7th BF and 10th BF, all P < 0.001), EMD (P, 0.001), EMA (P < 0.001), percentage of leaf and caul fat (PLC) (P < 0.05), proportion of lean and bone of the ham (PLBH) (P < 0.05), muscle drip loss percentage (DL) (P < 0.05) and intramuscular fat content (IMF) (P < 0.05). The breed-sex interaction only impacted the average daily gain from birth to marketing (ADG1) and DL (both P < 0.05). However, there was no significant effect of sex-parity interaction on all the traits tested.     

茵陈汤对饥饿鲤体质量、生物学性状、体成分及血清生化指标变化的影响

试验主要评估茵陈汤对饥饿鲤物质代谢及健康的作用,为鲤的健康高效养殖以及饲料开发提供依据。将210尾鲤(平均体质量19.90 g±2.65 g)以每箱35尾随机投放于6个室内网箱,分为对照组和茵陈汤组,饲以分别添加0%、0.9%茵陈汤的试验饲料56 d,然后每箱随机选取8尾体格健壮的鲤进行为期30 d的饥饿试验。饥饿试验前后进行鱼体生物学性状、体成分、血清指标的检测。结果表明在饲养试验中,鲤的生长性能、生物学性状、肌肉中水分、粗蛋白、粗脂肪含量、肝胰脏常规成分两组之间均无显著差异(P0.05),肌肉中粗灰分含量、血清ALT水平茵陈汤组显著低于对照组(P0.05),其他血清生化指标无显著差异(P0.05);饥饿后茵陈汤组的减量率显著低于对照组(P0.05),肥满度、肝胰脏水分含量显著高于对照组(P0.05),肌肉和肝胰脏粗蛋白、粗脂肪、粗灰分含量两组之间均无显著差异(P0.05);两阶段间,茵陈汤组鲤饥饿后脾脏指数显著高于饲喂后(P0.05),肥满度显著低于饲喂后(P0.05),其他生物学指标两组均分别显著低于饲喂后(P0.05)。肌肉中水分、粗蛋白、粗灰分含量饥饿后两组均分别显著高于饲喂后(P0.05),粗脂肪含量显著低于饲喂后(P0.05),茵陈汤组肝胰脏变化趋势与肌肉相符。饥饿后血清HDL、LDL、CHOL水平显著高于饲喂后(P0.05),其他血清指标两组均分别显著低于饲喂后(P0.05)。从饥饿前后鲤体质量、体成分及血清生化指标的变化,说明茵陈汤对鲤体内物质和能量代谢具有一定的影响,可以促进脂肪的利用,并减缓机体对营养物质的快速消耗,有利于体质量的维持。同时,茵陈汤有助于鲤的健康养殖,对鲤的肝胰脏具有一定保护作用。     

Cellular immune responses of BALB/c mice induced by intramuscular injection of PRRSV-ORF5 DNA vaccine with different doses

BALB/c mice were immunized with 50 μg, 100 μg, 200 μg of pcDNA-PRRSV-ORF5 DNA vaccine respectively by intramuscular injection, with PBS and pcDNA3.1(+) as controls. Fluorescence activated cell Sorter (FACS) was used to detect the number of CD₄ ⁺ and CD₈ ⁺ T-lymphocytes. T-lymphocyte proliferation test was used to detect proliferation of the T-lymphocyte cells in peripheral blood lymphocytes of mice vaccinated with pcDNA-PRRSV-ORF5 DNA vaccine. The results showed that the difference in ConA response to T-lymphocytes in blood was highly significant between all experimental groups and the control group (P < 0.01). The number of CD₄ ⁺ T-lymphocytes in experimental groups was significantly higher than that of the control group 7 d after vaccination. The number of CD₈ ⁺ T-lymphocytes in the experimental groups was higher than that of the control group 28 d after vaccination. Mice immunized with a higher dose (200 μg) of DNA vaccine demonstrated higher cellular immune response than those immunized with a lower dose (100 μg, 50 μg) of DNA vaccine. The results demonstrated that pcDNA-PRRSV-ORF5 DNA vaccine could induce a good cellular immune response which may be dose-dependent. __________ Translated from China J Vet Sci Mar, 2006, 26(2): 111–114 [译自: 中国兽医学报] The first three authors contribute equally to this work.     

Effect of cell mediated immunity regulation of duck enhanced by duck IFN-α eukaryon expression plasmid and inoculated with DPV attenuated vaccine by gene-gun

In order to study the effect of cell mediated immunity regulation of duck IFN-α eukaryon expression plasmid (pcDNA-SDIFN-α) on duck plague virus (DPV) attenuated vaccine in ducks, pcDNA-SDIFN-α was administered to 28-day-old ducks at doses of 1, 3 and 6 μg per duck, respectively, by gene-gun. PBS and empty vector pcDNA were used as control. Fifteen days later, all ducks were injected with DPV attenuated vaccine and blood samples were collected at 3, 7, 14, 21, 28, 35, 49, 63 and 84 days after injection. T-lymphocyte proliferation tests (MTT) were used to detect the T-lymphocyte proliferation in the peripheral blood (PBL) of ducks. Blood samples collected at 7, 14, 21, 28, 35 and 49 days after injection were detected by fluorescence-activated cell sorter (FACS) for recording the number of CD₃ ⁺ T-lymphocytes of ducks. Results were as follows: (1) Reaction of T-lymphocytes in PBL to ConA (OD value) of ducks treated with pcDNA-SDIFN-α was higher than that of PBS and pcDNA control groups in 3–84 days. There were highly significant differences between the 1 μg per duck group and the two control groups in 3–84 days (P ⩽ (0.01), between the 3 μg per duck group and the two control groups in 3–84 days (P ⩽ 0.01, P ⩽ 0.05), and between the 6 μg per duck group and the two control groups in 7–49 days (P ⩽ 0.01, P ⩽ 0.05). The significant difference was also present between the groups of 1, 3 and 6 μg per duck in 3–35 days (P ⩽ 0.05). However, there was no significant difference between the 3 and 6 μg per duck groups (P ⩾ 0.05). The pcDNA control group was higher than PBS control group, but no difference was detected (P ⩾ 0.05). (2) Change of the number of CD₃ ⁺ T-lymphocytes in ducks administered with different doses of pcDNA-SDIFN-α was higher than that of PBS and pcDNA control groups in 7–49 days. The change in the 1 μg per duck group was significantly higher than that in PBS and pcDNA control groups in 14–49 days (P ⩽ 0.01). There were significant differences between the 3 μg per duck group and the two control groups in 21–49 days (P ⩽ 0.01, P ⩽ 0.05) and between the 6 μg per duck group and the two control groups in 7–49 days (P ⩽ 0.01, P ⩽ 0.05). However, no significant differences among the groups of 1, 3, and 6 μg per duck groups (P ⩾ 0.05) and between the two control groups (P ⩾ 0.05) were found. The results indicated that pcDNA-SDIFN-α administered 15 days before injection of DPV-attenuated vaccine could significantly enhance cellular immunity induced by DPV-attenuated vaccine. pcDNA-SDIFN-α is an excellent DPV-attenuated vaccine molecular adjuvant and the best result can be obtained with the dose of 1 μg per duck of pcDNA-SDIFN-α inoculated by gene-gun. __________ Translated from Acta Veterinaria et Zootechnica Sinica, 2007, 38 (10): 1066–1071 [译自: 畜牧兽医学报]     

Effect of mating combination and environmental factors on hatchability of chicken eggs in Tibet

To improve the hatchability of introduced high-yield chickens in Tibet, and ameliorate the egg yield and reproduction traits of the local Tibetan chickens, four mating combinations between the Recessive White and Tibetan chicken were employed to investigate the effect of the mating combination and environmental factors on hatchability in this study. The results showed that the fertility of the eggs with Tibetan chicken as female parent was significantly lower than that with Recessive White as female parent (P < 0.05), while hatchability was the reverse (P < 0.05). The embryonic mortality of Recessive White was significantly higher by 7.95% than the Tibetan chickens, particularly during the last stage of incubation. The hatchability of combination III, whose female parent was Tibetan chicken, was higher by 20.44% than combination II, whose female parent was Recessive White. This provided a theoretical basis for a cross using the Tibetan chicken as female parent. Binary logistic regression analysis results also showed that the mating combination and environmental temperature were of importance to egg hatchability. Translated from Acta Veterinaria et Zootechnica Sinica, 2006, 37(1): 28–33 [译自: 畜牧兽医学报]     

Effects of microbial agents on small intestinal structure and the quantity of cecal microorganisms in broilers

In order to elucidate the significance and related mechanisms of microbial agents in modulating the growth of broilers, one-day-old Avian broilers were employed to investigate the effect of microbial agents on body weight, daily gain and feed efficiency at various stages. The birds in the experimental groups were given salmonella pullorum then fed with antibiotics to counteract it. The results showed that the average broiler weight of the oral microbial agent group at the age of 40 days was significantly increased by 16.58% from 1520 g to 1772 g (P < 0.05). The feed conversion efficiency was decreased from 2.21 to 1.82 (P < 0.01). In the experimental group fed with microbial agents, microscopic observation revealed that the intestinal villi increased in number, length and orderliness. The intestinal wall became thickened. The glands in the intestine were developed, which would be beneficial to nutrient absorption. The effect of oral microbial agents was identical to that due to antibiotics. It was also observed that Lactobacillus dominated the cecal microorganisms in broilers.     

Effects of Chinese herbal formula Heat-stress-releasing on antioxidant function in dairy cows

In order to investigate the effects of a Chinese herbal formula Heat-stress-releasing on the antioxidant function in dairy cows, ten dairy cows were randomly divided into the control group and the experimental group, with five cows in each group. All the cows were fed with a basal diet. The animals in the experimental group were given with 220 g of herbs per day in addition to the basal diet. The trial was conducted for 14 days. Blood samples were taken from the vena cava at day 0, day 7, and day 15, respectively. The antioxidant statuses were examined. The results are as follows. (1) Heat-Stress-releasing formula can significantly increase the milk yield of dairy cows under heat stress. Compared with the control group, the milk yield of the herb-treated group increased by 14.01% (P<0.05), 14.32% (P<0.05) and 15.01% (P<0.05) in prophase, metaphase and anaphase of the test, respectively. (2) Heat-Stress-releasing formula can increase significantly the antioxidant status of the heat stressed dairy cows. Compared with the control group, the superoxide dismutase (SOD) activity increased by 45.93% (P<0.01) at day 7 and by 54.40% (P<0.01) at day 15. The Glutathioneperoxidase (GSH-PX) activity of the test group increased by 17.99% (P<0.05) at day 7 and 25.98% (P<0.01) at day 15. The total antioxidant capacity (T-AOC) of the test group increased by 43.64% (P<0.01) at day 7 and 46.35% (P<0.01) at day 15. The malondaldehyd (MDA) content of test group declined by 23.88% (P<0.01) at day 7 and 25.32% (P<0.01) at day 15.     

Genetic differentiation and gene flow among six sheep breeds of Mongolian group in China

The level of genetic differentiation, gene flow and the relationship between geographical distance and genetic differentiation among six sheep populations of Mongolian group in China (Tong sheep, small-tailed Han sheep, Hu sheep, Tan sheep, Ujumuqin sheep and Bayinbuluk sheep) were analyzed using seven microsatellites. The trees were constructed from diversity coefficient (DC) distances among the six sheep populations. The overall heterozygote deficit across all the populations (F _it) was between 0.167 (OarAE101) and 0.044 (MAF33). The over-all significant deficit of heterozygote, because of inbreeding within breeds, (F _is) was between 0.089 (OarFCB304) and 0.005 (MAF33). The coefficient of genetic differentiation (F _st) was between 0.100 (OarAE101) and 0.022 (OarFCB48). It indicated that 3.9% of the total genetic variation could be explained by breed differences and the remaining 96.1% by differences among individuals for each population. This illustrated that most variations existed within breeds and genetic differentiation level were very low among sheep breeds of the Mongolian Group in China. The average number of effective migrants exchanged per generation (Nem) ranged from 2.7369 (Tan sheep and Bayinbuluk sheep) to 44.3928 (Tong sheep and Hu sheep), and the mean value was 11.25213. Significantly positive relationships between the level of genetic differentiation and geographical distance and genetic distances were detected. It is concluded that genetic differentiation of sheep breeds of Mongolian group in China is mainly the result of natural selection (different living conditions). __________ Translated from Journal of Yangzhou University (Agricultural and Life Science Edition), 2007, 28(3): 22–26 [译自: 扬州大学学报(农业与生命科学版)]     

Response of lactating cows to supplemental rumen protected methionine and Niacin

Eight Chinese Holstein cows were used in a 4 × 4 Latin square design to determine the effects of rumen protected methionine (RPMet) and Niacin on milk yield and milk composition of lactating cows with 14 d adaptation and 6-d sampling periods. The cows were fed the control diet or the control diet plus RPMet (25 g·⁻¹), niacin (6 g·⁻¹), or RPMet (25 g·⁻¹) + niacin (6 g·⁻¹). The results showed that RPMet supplementation in the diet increased 4% fat corrected milk (FCM) yield (P < 0.05) and milk fat percentage (P < 0.05). However, supplemental RPMet had no effect on the solid non fat (SNF) (P > 0.05) and lactose percentage (P > 0.05). Dietary niacin supplementation increased milk yield (P < 0.05), milk protein percentage (P < 0.05) and lactose percentage (P < 0.05), but had no effect on milk fat percentage (P > 0.05) and SNF (P > 0.05). RPMet supplementation in the diet of lactating cows significantly decreased serum urea nitrogen (P < 0.01) and glucose contents (P < 0.05), but had no effects on nonesterified fatty acids (NEFA), total cholesterol and triglyceride (P > 0.05). Niacin supplementation influenced the contents of glucose and NEFA in serum, but had no effects on the urea nitrogen, total cholesterol and triglyceride (P > 0.05).     

Regulation of bone phosphorus retention and bone development possibly by BMP and MAPK signaling pathways in broilers

The bone morphogenetic protein(BMP) and mitogen-activated protein kinase(MAPK) signaling pathways play an important role in regulation of bone formation and development,however,it remains unclear that the effect of dietary different levels of non-phytate phosphorus(NPP) on these signaling pathways and their correlations with bone phosphorus(P) retention and bone development in broilers.Therefore,this experiment was conducted to investigate the effect of dietary P supplementation on BMP and MAPK ...     

Initial function determination for the open reading frame (ORF) region of Pib gene via rice transformation

Three plant binary expression vectors—pNAR501, pNAR502 and pNAR503—were constructed, carrying fragments of exon2-exon3, 5′partial deletion exon1 and 5′partial deletion exon1-exon2-exon3 of Pib gene driven by 35S. These three vectors were transformed into the japonica rice variety Nipponbare through agrobacterium-mediated transformation. More than 30 transgenic rice plants were obtained and confirmed by polymerase chain reaction (PCR), Southern hybridization and the hygromycin resistance test in seed germination of their progeny. A rice blast resistance test for in vitro leaves of T_o transgenic plants in the tillering stage showed higher resistance to the races of E1, F1 and G1 of rice blast than that of the control Nipponbare. However, results of rice blast resistance test for seedlings of T₁ transgenic plants in the 3-to 4-leaf stage were different. All T₁ transgenic seedlings had a lower level of resistance to E1, F1 and G1 races than that of the control Nipponbare. Translated from Journal of Nanjing Agricultural University, 2006, 29(3): 1–5 [译自: 南京农业大学学报]     

生长调节剂对降香黄檀营养生长与生殖生长的影响

【目的】研究生长调节剂对降香黄檀Dalbergia odorifera营养生长与生殖生长的影响,为不同经营目标的降香黄檀人工林生产提供技术支撑。【方法】以10年生降香黄檀为研究材料,采用随机区组试验设计,通过叶面喷施3种不同浓度的赤霉素(GA3)、多效唑(PP333)和6-苄氨基嘌呤(6-BA),测定盛花期内一年生新梢、花、叶的形态生长和干质量变化,再运用统计分析软件,对各种生长调节剂处理后营养生长和生殖生长的变化规律进行分析。【结果】不同种类和不同浓度的生长调节剂对降香黄檀营养生长和生殖生长的影响差异均达显著水平(P0.05)。叶面喷施200、100 mg·L~(-1)的GA3和500 mg·L~(-1)的6-BA均能显著促进降香黄檀的营养生长,抑制其生殖生长;其中,200 mg·L~(-1)的GA3对生殖生长的抑制效果最理想,施用后其营养枝率比对照显著提高140.84%,花序数显著降低79.41%;100 mg·L~(-1)的GA3对营养生长效果显著,施用后其营养枝枝长、直径、复叶数和单叶干质量分别比对照提高218.08%、120.70%、132.38%和217.33%,且均达显著水平。1 500、2 000 mg·L~(-1)的PP333和50 mg·L~(-1)的6-BA均能显著促进降香黄檀的生殖生长,以2 000 mg·L~(-1)的PP333作用效果较好,处理后其花枝率、花序数量和花序径依次比对照提高73.50%、50.37%和31.30%,且均达显著水平。【结论】降香黄檀人工林培育中,叶面喷施200或100 mg·L~(-1) GA3能显著抑制生殖生长、促进营养生长,有利于大径级木材培育,2 000 mg·L~(-1)的PP333则有利于生殖生长,有利于良种壮苗生产。     

饥饿程度对大鼠学习记忆能力影响的实验研究

目的 探究不同的饥饿程度对大鼠的空间学习记忆能力的影响。方法 将84只成年健康雄性SD大鼠随机分为8组,A-G组分别饥饿处理6、18、24、30、36、42 h,H组饱食处理作为对照组,应用Morris水迷宫对SD雄性大鼠进行行为训练,评价其对大鼠空间学习记忆能力的影响。结果 （1）A-G组不同饥饿处理的各组大鼠定位航行实验潜伏期呈现先减小后增大的趋势,饥饿24 h组VS对照组（22.58±4.44）s VS（29.23±6.81）s,P<0.01;饥饿36 h组VS对照组（35.58±4.89）s VS（29.23±6.81）s,P<0.05。空间探索实验穿越原平台次数,饥饿24 h组VS对照组：（3.18±0.72）次VS（2.33±0.67）次,P<0.05;饥饿42 h组VS对照组：（1.64±0.64）次VS（2.33±0.67）次,P<0.05,呈现先增大后减小的趋势;同样,目标象限滞留时间百分比也是呈现先增大后减小的趋势,饥饿24 h组VS对照组（40.06±3.65）% VS（33.64±4.55）%,P<0.05;饥饿42 h组VS对照组（26.70±4.50）% VS（33.64±4.55）%,P<0.05。（2）上述实验结束后的G组连续饥饿处理42 h定位航行实验的潜伏期呈现减小后缓慢增加的趋势,连续饥饿处理时间6 h VS连续饥饿处理时间24 h（28.74±5.24）s VS（20.88±4.3）s,P<0.01;连续饥饿处理时间6 h VS连续饥饿处理时间30 h（28.74±5.24）s VS（19.97±6.14）s,P<0.01。结论 短期的饥饿（18 h和24 h）有助于大鼠空间学习记忆能力的提高,长期的饥饿（36 h和42 h）处理使大鼠的学习记忆能力下降。     

Effects of different fertilization on microbial biomass carbon from the red soil in tea garden

The present study examined the influence of the different fertilization on the dynamic of soil microbial biomass carbon (SMBC) of red soil in tea gardens. The results showed that straw mulching, intercropping, chemical fertilizer could all improve the amount of the soil microbial biomass C. The annual variation of microbial biomass C showed the tendency of “low-high-low-high”, and the influences were variable with the time. For the annual average of soil microbial biomass C, Treatment 1(T₁) (straw mulching + 100% organic manure), Treatment 2 (T₂) (straw mulching + 75% organic manure + 25% fertilizer), Treatment 3 (T₃) (straw mulching + 50% organic manure + 50% fertilizer), Treatment 4 (T₄) (straw mulching + 25% organic manure + 75% fertilizer), Treatment 5 (T₅) (100% fertilizer),Treatment 6 (T₆) (intercropping white clover) were 17.05%, 32.38%, 32.05%, 24.30%, 26.23%, 24.63% higher, respectively, than CK, and the differences among all the treatments were significant (P < 0.05). The correlation of the SMBC with the active organic matter, the total nitrogen, the microbial biomass N, the microbial biomass P were remarkable, but no significant correlation was found with available nitrogen, total phosphorus, total potassium and moisture. Compared with other treatments, those mixed with organic matter and chemical fertilizer were more advantageous to enhance the soil fertility. __________ Translated from Chinese Journal of Ecology, 26(7): 1009–1013 [译自: 生态学杂志]     

Research on Yucca schidigera extract feeding on the rumen ecology, protozoal populations and serum chemistries of sheep

In a completely randomized block design experiment, 16 ruminally cannulated male sheep with body weights of (40 ± 2.1) kg were fed twice daily (8:00 and 16:00) with concentrate and forage (50:50 on dry matter (DM) basis). Dietary treatments were supplemented with intraruminal doses of powdered Yucca schidigera extract (YSE) at the levels of 0 (control), 100, 200 and 300 mg · kg⁻¹. On days of 15, 16 and 17 after feeding, ruminal content was sampled at 0, 2, 4, 6 and 8 h after dosing (8:00), and blood samples were collected at the end of experiment (the days 18 and 19 after feeding). Results showed that the treatment groups’ acidity was not affected (P = 0.13) by YSE. Comparing to the control, the ruminal propionate concentration was increased by YSE addition in a dose-dependent manner by up to 29.8% (P < 0.05), and the acetic concentration was decreased by up to 17.5% (P < 0.05). The ruminal ammonia concentration 2 hours after feeding was higher (P < 0.05) in sheep fed without YSE (increased by 17.57 mg· 100 mL⁻¹) than those fed with YSE at 200 mg · kg⁻¹ (6.77 mg · 100 mL⁻¹ increase in NH₃) and at 300 mg · kg⁻¹ (6.50 mg· 100 mL⁻¹ increase in NH₃). Protozoal populations in the rumen were lower (P < 0.05) with the YSE feeding dose at 300 mg · kg⁻¹ than the control. The serum chemistries were not different among treatments (P > 0.05) and were within the normal physiological ranges for sheep 19 days after feeding. The study indicated that 200 mg· kg⁻¹ and 300 mg· kg⁻¹ YSE groups had particular suppressing effects on ruminal ammonia concentration, ammonia-N concentrations and protozoal populations. The effect of YSE on ruminal fermentation could be attributed to the selective inhibitory effect on rumen microbial species. High level (300 mg · kg⁻¹) YSE as feed additives resulted no negative impact on sheep in our tests.     

21～42日龄肉鸡能量和蛋白质需要量的研究

以商品代艾维茵肉鸡为供试动物,设置3个日粮代谢能(ME)水平,分别为12.55、12.97和13.38 MJ/kg;4个粗蛋白(CP)水平,分别为18.5%、19.0%、19.5%和20.0%.采用3×4因子设计进行饲养试验, 研究日粮ME和CP水平对22～42日龄肉鸡生产性能、胴体性能以及肉品质的影响.结果表明:(1)日粮ME水平对22～42日龄肉鸡的日均采食量、平均日增体质量、料重比和21日体质量影响极显著(P<0.01);日粮CP水平对22～42日龄肉鸡的日均采食量影响不显著(P>0.05),但对平均日增体质量、42日体质量和料重比影响极显著(P<0.01).日粮ME和CP的互作对22～42日龄肉鸡料重比影响极显著(P<0.01);较高的日粮ME水平和CP水平可获得理想的生产性能;(2)日粮ME水平对22～42日龄肉鸡半净膛率、腿肌率和腹脂率影响极显著(P<0.01),对屠宰率影响显著(P<0.05),对全净膛率和胸肌率影响都不显著(P>0.05);日粮CP水平与22～42日龄肉鸡的胸肌率呈正相关,对其他胴体性能指标影响不显著(P>0.05);(3)随日粮ME水平增加,腿肌的红度(a*)先降低后增加,但对胸肌红度(a*)影响不显著(P>0.05);胸肌和腿肌的黄色度值(b*)都与日粮ME和CP水平呈正相关;日粮ME水平对胸肌的亮度(L*)影响不显著(P>0.05);(4)胸肌的PH值与日粮ME水平呈负相关,腿肌的pH值随日粮CP水平的升高呈先上升后下降趋势;腿肌的持水率与日粮ME水平呈正相关.通过本试验并结合生产实际认为: 22～42日龄肉鸡适宜的ME水平为12.97MJ/kg,CP水平为19.0%～20.0%之间.