饲粮n-6/n-3多不饱和脂肪酸比例对畜禽健康和产品品质的影响

现今人类膳食中n-6多不饱和脂肪酸(PUFA)大多都是过量的,但n-3 PUFA却严重不足.研究表明,n-6/n-3 PUFA比例平衡对畜禽健康和产品品质有着重要意义,n-6/n-3 PUFA比例平衡成为当下最受关注的问题.本文综述了n-6/n-3 PUFA比例平衡的营养生理作用以及对畜禽产品品质的影响及如何改善畜禽产品中的n-6/n-3 PUFA比例.     

蜜蜂性比的分子调控机制研究

蜜蜂性比是指蜂群中雌性蜜蜂与雄性蜜蜂的比例。按亲属选择理论和性比原理预测 ,工蜂则可能对雌性性别更多地投资 ,这样蜂王和工蜂在决定性比问题上存在矛盾。本试验通过RAPD技术测定蜂王交配次数 ,并利用亲属选择和性比理论 ,研究了蜂群中的性比冲突问题。研究结果支持了工蜂调控蜜蜂性比的观点。     

Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel

Excessive stress response causes disability in social life. There are many diseases caused by stress, such as gastrointestinal motility disorders, depression, eating disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels underlie non-selective cation currents and are downstream effectors of G protein-coupled receptors. Ca²⁺ influx is important for smooth muscle contraction, which is responsible for gastrointestinal motility. Little is known about the possible involvement of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of this study was to measure the changes in gastrointestinal motility caused by stress and to elucidate the mechanism of these changes. The stress model used the water immersion restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was significantly reduced in the ileum of stressed mouse. Even under the conditions treated with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced contractions were all significantly reduced in the ileum of stressed mouse. Furthermore, the expression of TRPC3 was decreased in the ileum of stressed mouse. These results suggest that the gastrointestinal motility disorders due to stress is associated with specific non-selective cation channel.     

牛体外受精时老化卵对受精率与染色体异常发生的影响

通过延长体外培养时间得到牛老化卵，对其体外受精率与染色体的异常发生进行了研究，体外受精48h后的受精率，46h培养组与22h和34h培养组之间差异显著（P＜0．05），随着老化时间的延长，受精率及胚胎发育速度明显降低。染色体分析结果表明，46h组的受精卵的染色体异常发生率为61．6％，22h组44．6％，2组之间差异显著（P＜0．05），单倍体（n=31)的发生率也随着老化时间的延长而增加，这些单倍体的性染色体的构成表明，含有X－性染色体的胚的出现率显著高于含有Y－染色体的胚的出现率（P＜0．05）。单倍体的发生是由卵的老化而引起单一配子的孤雌发生，体外培养时间的延长对正常的2倍体的性别无明显影响。     

低蛋白质氨基酸平衡饲粮对生长猪生长性能和氮素减排的影响研究

试验旨在研究饲喂低蛋白质氨基酸平衡饲粮对生长猪生长性能和氮排泄量的影响,采用单因子完全随机设计,将144头平均体重30 kg左右的杜长大三元杂种生长母猪分成3组,每组设6个重复,每个重复8头猪,对照组饲喂实测粗蛋白质含量为18.10%的普通饲粮,试验1组、试验2组分别饲喂实测粗蛋白质含量为16.08%和14.12%的氨基酸平衡饲粮。试验期37 d,前7 d为预试期,正试期30 d。结果显示,3组日采食量、日增重、料重比指标均没有显著差异(P0.05),而日氮素总排泄量试验1组、试验2组分别比对照组减少18.69%、38.68%,3组之间差异均显著(P0.05),且试验1组、试验2组猪每增重1 kg所需要的饲料成本分别较对照组节省0.11和0.23元。综合考虑,生长猪饲喂低蛋白质氨基酸平衡饲粮,可以作为实现养殖效益与环保双赢的主要技术措施予以推广。     

行比对不同豆禾间作模式产量与品质的影响

豆禾间作是有效提高土地利用率的方式,有利于缓解江淮地区草地面积不足的情况。本研究在2017-2018年,通过对五个播种比例下的金花菜（Medicago polymorpha L.）+燕麦（Avena sativa L.）间作与箭筈豌豆（Vicia sativa L.）+燕麦间作进行比较;通过其产量及营养价值等数据评价其优劣。结果表明,箭筈豌豆与燕麦比例3.3：8的间作具有最高总干草产量,为1 595.72 g·m^-2。金花菜与燕麦比例6.6：4的间作具有最高的土地当量比和土地利用率,分别为1.36和132.58%,且总干草产量第二。竞争力指数表明金花菜的种群竞争力要高于箭筈豌豆。在营养价值方面,金花菜+燕麦间作更具优势;燕麦与金花菜间作后的粗蛋白含量达到13.88%~14.09%,高于箭筈豌豆间作中的13.19%~13.44%。综合来看,两种间作模式各有优劣,以燕麦产量为导向时,箭筈豌豆+燕麦比例为6.6：4和3.3：8的间作模式更优;而若是只考虑最高的土地利用率,则金花菜+燕麦比例为6.6：4的间作模式更优。     

Phenotypic plasticity induced using high ambient temperature during embryogenesis in domesticated zebrafish,Danio rerio

Ambient temperature during early stages of life has a substantial effect on physiological processes, eliciting phenotypic plasticity during zebrafish developmental stages. Zebrafish are known to possess a noteworthy ability to modify their phenotype in dependence of environmental factors. However, there is a poor understanding of the effects of temperature during embryogenesis, which influences the biological functions such as survival ability and masculinization in later developmental stages. Since the middle embryonic phase (pharyngula period) is genetically the most conserved stage in embryogenesis, it is very susceptible to embryonic lethality in developmental processes of vertebrates. Here, we tested the effect of transient perturbations (heat shock) during early development (5–24 hr post‐fertilization; hpf) at 35°C compared to control group at 28°C, on survival ability of zebrafish to study the embryonic and post‐embryonic mortality. We studied the variation of heat‐induced masculinization among and across the families in response to high temperature. Furthermore, morphometric traits of adult zebrafish at different developmental time points were measured in order to estimate the temperature × sex interaction effect. We found the highest embryonic mortality around the gastrula and segmentation periods in both experimental groups, with significantly lower survival ability in the temperature‐treated group (73.30% ± 0.58% vs. 70.19% ± 0.57%, respectively). A higher hatching success was observed in the control group (71.08% ± 0.61%) compared to the heat‐induced group (67.95% ± 0.60%). A distinct reduction in survival ability was also observed in both experimental groups during the first two weeks after hatching, followed by a reduced level of changes thereafter. We found sex ratio imbalances across all families, with 25.2% more males under temperature treatment. Our study on growth performance has shown a positive effect of increased temperature on growth plasticity, with a greater impact on female fish in response to high ambient temperature.     

不同苜蓿品种在青岛地区的适应性

2007-2010年,在青岛地区对引进的23个国内外苜蓿品种进行了膜侧种植、无灌溉、无施肥模式的田间试验,观测分析了各品种产草量、株高、茎叶比等指标。结果表明,23个苜蓿品种在青岛普遍生长良好,国外品种生产性能优于国内品种;播种当年干草产量膜侧种植组明显高于直接播种组,干草产量增幅(除甘农4号、新疆大叶和牧歌401外)均在50%以上;干草产量与年均日照时数、年均温的灰色关联度分别达到0.795 5和0.878 9,而与年均降水量关联度仅为0.569 1;株高最高的是WL323为87.8 cm,最低的是敖汉苜蓿,仅74.7 cm;供试23个品种的干草产量与株高均存在显著性差异,株高与草产量相关系数达到0.65以上,具有很高的正相关性;茎叶比最低的是牧歌401,仅为1.22,绝大多数苜蓿品种的茎叶比有逐年增加的趋势。综合评价认为供试23个苜蓿品种中的WL323、牧歌401、驯鹿3个品种综合生产性能较好,适宜在青岛地区辅以膜侧种植模式进行大面积推广。     

Radiosensitivity and capacity for radiation-induced sublethal damage repair of canine transitional cell carcinoma (TCC) cell lines

Understanding the inherent radiosensitivity and repair capacity of canine transitional cell carcinoma (TCC) can aid in optimizing radiation protocols to treat this disease. The objective of this study was to evaluate the parameters surviving fraction at 2 Gy (SF(2) ), α/β ratio and capacity for sublethal damage repair (SLDR) in response to radiation. Dose-response and split-dose studies were performed using the clonogenic assay. The mean SF(2) for three established TCC cell lines was high at 0.61. All the three cell lines exhibited a low to moderate α/β ratio, with the mean being 3.27. Two cell lines exhibited statistically increased survival at 4 and 24 h in the dose-response assay. Overall, our results indicate that the cell lines are moderately radioresistant, have a high repair capacity and behave similarly to a late-responding normal tissue. These findings indicate that the radiation protocols utilizing higher doses with less fractionation may be more effective for treating TCC.     

Risk Factors for Lamb Mortality in Sahelian Sheep on a Breeding Station in Ghana

A retrospective cohort study was designed to examine the effect of sex, season of birth, type and year of birth, and birth weight on lamb mortality. The method used involved analysis of breeding records for Sahelian sheep kept on a breeding station at Pong-Tamale in northern Ghana from 1994 to 2000. The pre-weaning and post-weaning mortalities were 10% (n = 505) and 19% (n = 453), respectively, while the overall mortality from birth up to 12 months of age was 28% (n = 505). Compared to the pre-weaning period, the post-weaning period recorded significantly higher proportions of deaths in male, single-born, lambs born in the rainy or dry seasons, and in lambs with low (<3 kg) or high (> or =3 kg) birth weight. The odds and risks of death for male lambs were about one and a half times those for females at post-weaning. Lambs born in the dry season had significantly higher mortality than those born in the rainy season. Lambs that died by the time of weaning were not significantly different in weight at birth from those that survived. The mean birth and weaning weights of single-born lambs were significantly higher than those for twins. The mean pre-weaning ADG was significantly higher in lambs born as singles compared to that for twins. The season of birth had influence on mean birth weight, with those born in the rainy season having significantly higher weights than those born in the dry season. The year of birth significantly affected birth weight, weaning weight, weight at 12 months and ADG at all stages of the lambs' life. The study concluded that the most significant risk factors for lamb mortality included sex of the lamb, season of birth and birth weight. The last two could be manipulated, to some extent, to reduce lamb mortality.