不同比例游离脂肪酸对体外发酵参数的影响

采用体外培养方法研究添加不同比例的亚油酸和亚麻酸对瘤胃发酵的影响。以微晶纤维素为发酵底物,混合酸的添加量为5mg,添加比例分别为0∶0、5∶0、4∶1、3∶2、1∶1、2∶3、1∶4和0∶5,每个处理设4个重复。结果表明:随着游离脂肪酸不饱和度的增加提高了培养液中pH值和NH3-N浓度,降低了挥发脂肪酸、24h微晶纤维素的消失率和产气量。     

Genetic and phenotypic parameters and annual trends for growth and fertility traits of Charolais and Hereford beef cattle breeds in Kenya

This study estimated genetic and phenotypic parameters and annual trends for growth and fertility traits of Charolais and Hereford cattle in Kenya. Traits considered were birth weight (BW, kg), pre-weaning average daily gain (ADG, kg/day) and weaning weight (WW, kg); calving interval (CI, days) and age at first calving (AFC, days). Direct heritability estimates for growth traits were 0.36 and 0.21; 0.25 and 0.10; 0.23 and 0.13 for BW, ADG and WW in Charolais and Hereford, respectively. Maternal heritability estimates were 0.11 and 0.01; 0.18 and 0.00; 0.17 and 0.17 for BW, ADG and WW in Charolais and Hereford, respectively. Direct-maternal genetic correlations ranged between −0.46 and 1.00; −0.51 and −1.00; −0.47 and −0.39 for BW, ADG and WW in Charolais and Hereford, respectively. Genetic correlations ranged from −0.99 to unity and −1.00 to unity for growth and fertility traits respectively. Prospects for improvement of growth and fertility traits exist.     

沙地一年生植物五星蒿的构件特征研究

在甘肃省古浪县鸣沙咀,对典型沙生植物五星蒿Bassia dasyphylla形态及生物量空间分布特征进行研究。结果表明：冠幅、地径、根深、根幅、侧根数量与长度均与高度呈极显著线性正相关(P＜0.01),其中地上部形态指标与高度的相关程度相对地下部较高;枝条分枝数量较多,一级分枝数为30.40个,二级分枝数达到了260.87个。五星蒿单株平均生物量为75.21 g,其中地上生物量为67.83 g,地下生物量仅为7.38 g;地上生物量集中于1030 cm,占地上生物量的77.64％,各构件依生物量的大小依次为：枝条、果实、叶片;地下生物量集中于010 cm,占地下生物量的76.29％,侧根较主根发达;不同层次间各构件鲜、干生物量的差异性基本相似,地上部分的差异主要表现在1020、2030与3040、4050 cm之间,地下部分的差异主要表现在010与1020、2030 cm之间,其他各层次相互之间的差异相对不显著。     

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调查了中国西北和东部地区不同生境的拂子茅属Calamagrostis植物中Neotyphodium属内生真菌的分布。采样范围包括新疆、青海、甘肃、江苏、安徽、浙江、上海7省（市、区）,共采集拂子茅属植物样品426株。调查发现西北3省（区）所有276个拂子茅属植物样品中都不含有内生真菌;而采集自东部的样品中,南京的无性系拂子茅属植物和黄山的拂子茅C. epigeios含菌率为100%。但是,采自南京抽穗的拂子茅却完全不含内生菌。通过研究分离菌株的形态学特征,发现南京与黄山的菌株都具有Neotyphodium属内生真菌的典型特征,而它们之间在菌落形态、生长速度、孢子大小等方面又存在较明显差异。以上结果说明我国拂子茅属植物及其中的禾本科植物内生真菌具有一定的生物多样性,拂子茅属植物中的内生真菌含量受地理环境以及宿主植物种类的影响十分明显。     

小熊猫血液生理生化指标的测定

为建立健康成体小熊猫血液生理生化参数指标,选择福州大熊猫研究中心圈养的28只（雌性20只,雄性8只）外观发育正常、临床检查健康的小熊猫作为试验对象,通过食物引诱自行进入夹笼,在无麻醉的情况下,静脉采血。用全自动血细胞分析仪和生化分析仪检测23项血液参数和25项血液生化参数。用SPSS11．5统计软件包对各参数计算平均值（X^-）和标准差（SD）,t检验比较雄性与雌性小熊猫相应指标的差异显著性。测定结果为小熊猫的疾病诊断、动物检疫和相关的研究提供科学的依据。     

Effects of treating rice straw with urea or urea and calcium hydroxide upon intake, digestibility, rumen fermentation and milk yield of dairy cows

Three, multiparous Holstein crossbred dairy cows with initial body weight of 385 ± 19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea + 2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)₂ in 100 ml to 100 g air-dry (91% DM) straw) according to a 3 × 3 Latin square design. Each period lasted for 21 days in which feed, feces and rumen fluid were collected during the last 7 days for chemical analyses. The findings revealed significant improvements in dry matter intake and digestibility by using 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw. Ruminal pH and NH₃-N were found higher (P < 0.05) as compared with urea-treated rice straw fed group, while blood urea nitrogen and milk urea nitrogen were in normal ranges. Volatile fatty acid concentrations especially those of acetic acid were decreased (P < 0.05) and those of propionic acid were increased (P < 0.05), thus acetic acid:propionic acid was subsequently lowered (P < 0.05) in cows fed with 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw, respectively. Moreover, ruminal viable and cellulolytic bacterial counts were enhanced by urea and calcium hydroxide treatments. Milk protein and fat concentrations were additionally increased by respective treatments while 3.5% fat-corrected milk was highest; ranking from 2.2% urea + 2.2% calcium hydroxide treated rice straw, 5.5% urea-treated rice straw and urea-treated rice straw fed groups. Based on this study, implications could be made that using 2.2% urea + 2.2% calcium hydroxide treated rice straw for straw treatment could be an alternative treatment to 5.5% urea treatment with regards to its effectiveness and treatment cost for lactating dairy cows.     

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

Genetic parameters of piglet survival traits and birth weight were estimated on the first generation data of a selection experiment aimed at improving piglet survival using a multiple trait linear and threshold model. Data on 5293 piglets for survival at birth, at day one after birth and during the entire nursing period, as well as individual birth weight and litter size, were recorded in an outdoor production system. Genetic effects of piglet survival traits and birth weight were estimated based on threshold and Gaussian models, respectively, using a Bayesian approach. The statistical model included as fixed effects selection group, parity, gender, fostering, gestation length and month of farrowing and, alternatively, an adjustment for litter size. Direct genetic effects (i.e. the piglet's genetic potential) for piglet survival and birth weight were estimated separately, whereas maternal genetic and environmental effects could only be estimated for the given data structure in a combined litter effect. Posterior means of heritabilities for direct genetic effects of survival at birth, at first day after birth and the entire nursing period, as well as birth weight, were 0.08, 0.07, 0.08 and 0.20, respectively. Genetic correlations among survival traits were in the range of 0.29 to 0.40 and indicate that these traits were mainly attributable to different genetic effects. Genetic correlations between direct effects of survival traits and birth weight ranged between 0.18 and 0.23 and were reduced when weights of stillborn piglets were omitted in the analysis or the traits were adjusted for litter size. The magnitudes of direct genetic effects of survival traits are substantially higher than estimates in the literature, which may indicate that these traits have a higher genetic influence under outdoor conditions. The use of birth weight in the multiple trait estimation provided important information for the estimation of survival traits due to its favourable genetic correlations with survival, its high heritability and its high information content as a continuously measured trait.     

伊犁河流域裸露缓坡地放水试验研究

 通过野外径流小区实地放水冲刷试验,研究伊犁河流域裸露缓坡地在不同放水条件下土壤水分变化、径流泥沙特征,并运用水力学理论分析坡面径流水力学参数特征。结果表明:1)土壤入渗率随着放水流量的增加呈现递增的趋势,随着放水量的增加,土壤表层含水量增大,入渗率随之减少,坡下部土壤水分变化量高于坡上;2)随着放水流量的增加,输沙率呈现递增的趋势,含沙量呈先增后减的趋势,含沙量与放水流量存在较好的幂函数关系,随着冲刷时间的延长,含沙量、输沙率均呈现递减的趋势;3)随着放水流量的增加,径流平均流速、雷诺数、Darcy-Weisbach阻力系数逐渐增大,弗劳德数逐渐减小,流速与流量、弗劳德数与雷诺数均呈良好的幂函数关系,水流为层流、急流状态。     

Effects of dietary fish oil replacements with three vegetable oils on growth,fatty acid composition,antioxidant capacity,serum parameters and expression of lipid metabolism related genes in juvenile Onychostoma macrolepis

Five isonitrogenous and isoenergetic diets with soybean oil (SO), linseed oil (LO), algae oil from Schizochytrium sp. (AO), mixed oil (MO, SO:LO:AO = 1:1:1) and fish oil (FO; control group) were selected to feed juvenile Onychostoma macrolepis (initial weight 1.86 ± 0.07 g) for eight weeks. The results showed that in the LO and FO groups fish grew best. There was no significant difference in specific growth rate (SGR) and feed efficiency (FE) between the MO and FO groups (p > .05). The highest contents of 18:2n‐6, 18:3n‐3 and 22:6n‐3 in liver and muscle were found with the SO, LO and AO groups, respectively (p < .05). There appeared the highest malondialdehyde (MDA) content and the lowest superoxide dismutase (SOD) activity in the fish liver of the AO group. There appeared the highest concentrations of serum glucose (GLU), cholesterol (CHOL) and triglycerides (TG) in the SO group. The expressions of lipid anabolism genes were significantly up‐regulated by dietary SO and LO (p < .05). The expressions of lipid catabolism genes were significantly higher with the AO, MO and FO groups (p < .05). This study recommended that LO or MO as a better vegetable oil source for juvenile O. macrolepis.     

Effects of environmental factors and food availability in Northern Aegean sea on the cultivation of Mediterranean Mussels (Mytilus galloprovincialis)

This study used two different collectors made of polypropylene (PP) rope and polyethylene (PE) fishing net to determine Mediterranean mussel's settlement, growth, condition index (CI), meat yield (MY) and shell thickness index (STI) during the period spent between June 2017 and November 2018. With this regard, chlorophyll a, water temperature, salinity, pH and particulate matter were defined through water samples that were collected on monthly basis triplicate. The mean chlorophyll a level was recorded as 0.32 ± 0.31 μg/L, while water temperature was 19.73 ± 5.14°C, salinity was 35 ± 2.070‰, pH was 8.12 ± 0.04, and TPM was 14.91 ± 10.48 mg/L. As a result of the cultivation period of 8 months spent following the first intense grip, the length of the mussels is measured as 31.79 ± 6.20 mm. Based on the Pearson correlation analysis results, the most important environmental parameter affecting Mediterranean mussels growth in length on PP rope collectors is the temperature (p < .05). The STI and CI were determined to be related with environmental temperature parameters, while no determinations could be obtained concerning the correlation of MY with environmental parameters. Assessment of Mediterranean mussels’ growth rate in PP rope collectors proved significant differences (p < .05) between March and November 2018. As no Mediterranean mussels are observed on PE fishing nets during the samplings performed throughout the study period, it is determined that PE fishing nets are not suitable collector types for Mediterranean mussel cultivation.