2008―2021年新疆审定长绒棉品种主要性状演变分析

为全面了解近年新疆育成长绒棉品种的特征特性,对2008―2021年新疆维吾尔自治区主要农作物品种审定委员会审定的43个早中熟长绒棉品种和4个当前待审品种的主要性状演变情况进行分析.结果表明:2012年以来审定品种的铃重较之前明显增加,普遍在3.40 g以上;衣分总体表现较为平稳,皮棉产量受气候环境等因素影响波动较大;纤...     

鳜浸泡嗜水气单胞菌全菌疫苗后皮肤黏液抗体的变化

应用间接ELISA方法,研究经嗜水气单胞菌(Aeromonas hydrophila)疫苗浸泡免疫后鳜(Siniperca chuatsi)皮肤黏液中抗体消长规律,以揭示鳜局部黏膜免疫在免疫保护中的作用及浸泡免疫的保护效果。结果表明,鳜皮肤黏液中抗体滴度在免疫后第7天达到峰值211,抗体从开始形成到消失持续21 d;添加佐剂(IMS1312、葡聚糖、莨菪碱、食盐)可以提高鳜皮肤黏液及血清中抗体滴度和相对免疫保护率,其中添加IMS1312组免疫保护率最高,达77.8%,免疫保护与抗体滴度成正相关(R2=0.79,P<0.05);以溶菌酶为代表的非特异性免疫在免疫后1周内即抗体未形成时,对鱼体起主要保护作用。此外,通过比较鳜血清与皮肤黏液中的抗体消长规律,发现血清中抗体滴度峰值出现时间较迟(第14天),抗体持续时间较长(42 d),初步推断鳜皮肤黏膜中可能存在相对独立于全身免疫系统的局部黏膜免疫系统。     

肉鸭3～7周龄预混料及全价饲料优化配方研究

本研究在“肉鸭3～7周龄基础日粮优化配方研究”的基础上，将筛选出的肉鸭3～7周龄2套基础日粮优化配方与3套不同类型的预混料配方进行组合，进行饲养试验与屠宰测定，观察肉鸭的生长速度、饲料报酬、成活率、单位增重饲料成本、屠体品质等性状。结果显示：本试验设计的预混料配方Ⅲ是肉鸭3～7周龄预混料优化配方，优化基础配方Ⅰ与预混料配方Ⅲ、Ⅱ的组合均为肉鸭3～7周龄全价饲料优化配方。     

Use of geographical information systems as a tool for predicting fish yield in tropical reservoirs: case study on Sri Lankan reservoirs

Use of geographical information systems (GIS) in inland fisheries has hitherto been essentially restricted to site evaluation for aquaculture development and assessment of limnological changes in time and space in individual water bodies. The present GIS study was conducted on the land-use pattern of the catchments of nine reservoirs in Sri Lanka, for which detailed fishery data, viz. yield, fishing intensity, landing size of major constituent species, together with selected limnological data such as conductivity and chlorophyll- a , were available. Potential statistical relationships (linear, curvilinear, exponential and second-order polynomial) of fish yield ( FY , in kg ha⁻¹ yr⁻¹) to different land-use patterns, such as forest cover ( FC , in km²) and shrub-land ( SL , in km²), either singly, or in combination, and/or the ratio of each land type to reservoir area ( RA in km²) and reservoir capacity ( RC in km³), were explored. Highly significant relationships were evident between FY to the ratio of SL and/or FC + SL to RA and/or RC . Similarly, the above land-use types to RA and RC ratios were significantly related to limnological features of the reservoirs. The relationships of FY to various parameters obtained in this study were much better correlated than those relationships of FY to limnological and biological parameters used in yield prediction in tropical and temperate lacustrine waters previously.     

Stimulation of acetylcholinesterase activity by triiodothyronine in the brain of Singi fish,Heteropneustes fossilis (Bloch)

Three consecutive days of injections of triiodothyronine (T₃)(0.038, 0.075, 0.15 and 1.54 nmoles/g) significantly elevated the acetylcholinesterase (AchE) activity in the brain of Singi fish, Heteropneustes fossilis (Bloch). The higher doses of 0.075, 0.15 and 1.54 nmoles of T₃/g induced a greater increase in enzyme activity than 0.038 nmoles/g. A T₃ dose of 0.019 nmoles/g was found to be ineffective. The T₃ action on AchE activity was blocked by cycloheximide. Thiourea treatment for 30 days decreased the AchE activity below the control level. This reduced level of the enzyme activity was brought back even above the control level by T₃ injections. It is, therefore, suggested that thyroid hormone is involved in the sustenance of AchE activity in fish brain.     

巨菌草饲粮对七彩山鸡生长性能、血清抗氧化能力和肠道菌群的影响

试验旨在研究巨菌草饲粮对七彩山鸡生长性能、血清抗氧化性能和肠道有害菌群数量影响.选取2周龄(初始体重104.59±3.82)g的七彩山鸡300只,随机分为5组,每组6个重复,每个重复10只,试验期112 d.对照组为Ⅰ组,饲喂不添加巨菌草的基础饲粮,Ⅱ组、Ⅲ组、Ⅳ组、Ⅴ组为试验组,分别在基础饲粮上添加4％、8％、12％...     

镜泊湖细鳞斜颌鲴的年龄与生长

本文报道了镜泊湖细鳞斜颌鲴的年龄生长特点。以鳞片上的年轮作为年龄鉴定依据。渔获物中1~+龄和2~+龄个体占52％以上,体长以14～26厘米为主。体长与鳞长之间呈直线相关L=0.1116+47.8754R。体重与体长呈指数函数相关 W=0.014L~(3.0?7?)。3~+ 龄以前生长较快,生长指标高,体长和体重的相对增长率大,以后转入成鱼生长阶段,其生长规律适合 von Bertalaffy 方程:L_t=38.5[1-e~(-0.328(t+0.446)];W_t=893.6[1-e~(-0.328(t+0.446)]~3。体重生长曲线的拐点位于 2.93龄的 W_t=0.32W_∞处,为成熟拐点。建议捕捞 3龄以上个体,并作为养殖对象加以发展。     

Effects of exogenous xylanase on performance,nutrient digestibility,volatile fatty acid production and digestive tract thermal profiles of broilers fed on wheat- or maize-based diet

1. A previous experiment reported that caecal temperature was negatively correlated with d 49 feed conversion ratio (FCR). This increased temperature in the caeca may indicate a prebiotic effect. An experiment was designed to investigate whether caecal temperature was affected in diets based on maize and whether other portions of the tract were affected.

2. A total of 25 Ross 308-d-old male broilers were allocated to each of 8 replicate pens per treatment. Treatments followed a 2 × 3 factorial design: two diets based on wheat or maize and three levels of enzyme addition, 0, 16 000 or 32 000 BXU/kg. Growth performance was assessed between d 1 and 49. Digestibility measurements were taken at d 28 and 49. On d 49, the excised small and large intestine of each bird was thermally imaged, weighed and volatile fatty acids (VFA) measured.

3. On d 28 and d 49, birds on the maize diets had higher feed intake and weight gain than those offered wheat diets. Additionally, on d 28, birds that received the maize diet had lower FCR than those offered the wheat diet. Enzyme improved FCR at d 49, independently of cereal. On d 28, enzyme improved the coefficient of apparent ileal DM digestibility and the coefficient of apparent ileal nitrogen digestibility. Enzyme only improved apparent ileal digestible energy in wheat-based diets (interactive term). On d 49, all digestibility parameters were improved by enzyme. Enzyme increased gizzard weight in maize-fed birds and the caeca of those fed wheat were heavier. The higher enzyme dose decreased duodenal temperature. In summary of VFA data, wheat-based diets produced more total VFAs and the total amount also increased with enzyme.

4. It appears from this study that there is equal potential in both wheat and maize diets for xylanase to improve performance of broilers probably through different mechanisms.