Dietary protein requirement of giant mud crab Scylla serrata juveniles fed iso-energetic formulated diets having graded protein levels

The protein requirement of juvenile mud crab Scylla serrata (body weight=0.25±0.051 g, carapace width=9.3±0.04 mm) fed with different iso-energetic, iso-lipidic diets with graded protein levels (15–55% crude protein at 5% intervals) was determined. The feeding trial was conducted for a period of 63 days to determine the minimum and optimum protein requirement of juvenile S. serrata . The crabs fed with 15% and 20% dietary protein levels showed 100% and 12.5% of mortalities respectively. The mortalities observed in the above treatments were associated with the prolonged intermoult duration (46 and 32 days respectively). All other treatments recorded 100% survival. The best growth performance as well as the nutrient turn-over was recorded in crabs fed with 45% crude protein in the diet. Second-order polynomial regression of specific growth rate (SGR) as well as body protein gain vs. dietary protein levels suggested that 46.9–47.03% dietary protein is required for the best growth response and protein deposition in juvenile S. serrata . An extrapolation of 'SGR' and 'daily protein gain' upon the 'dietary protein level' axis ( Y =0) showed that 14.7–16.2% dietary protein is necessary for the minimum maintenance metabolism.     

Efficacy of various lipid supplements in formulated pellet diets for juvenile Scylla serrata

Efficacy of sunflower oil (diet SF) and soybean oil (diet SB) alone and in combination with cod liver oil (diets M1‐2.80:1.40:1.40, M2‐2.80:2.24:0.56 and M3‐2.80:0.56:2.24; cod liver oil:sunflower oil:soybean oil) as lipid supplements (5.6%) in formulated diets (crude fat ～9.79%) for juvenile Scylla serrata (weight=0.28±0.07 g, carapace width=9.7±0.1 mm) were compared with diet CL, containing cod liver oil alone as the lipid supplement (6 diets × 24 crabs stocked individually, randomized block design). Growth performance, nutrient (protein and lipid) intake and gain of crabs fed M1, M2 and M3 were higher (P≤0.05) than the crabs fed SF and SB, but were not significantly different (P≥0.05) from crabs fed CL. Dietary fatty acids (FAs) are found to influence the FA profile of test crabs. Higher tissue levels of 16:1n‐7, 18:1n‐9 and 18:1n‐7 reflected the essential FA deficiency in crabs fed diets supplemented only with vegetable oils. Results confirmed that S. serrata could utilize vegetable oil supplements in the formulated diets as a partial replacement (50%) of cod liver oil without compromising growth and survival. Partial substitution of marine fish oil with suitable vegetable oils can reduce the feed cost considerably, in the context of rising fish oil prices.     

Choice preference of diets with different protein levels depending on water temperature in Nile tilapia

This study tested a choice feeding model for Nile tilapia that allowed the selection of a higher or lower protein content in the diet depending on water temperature. Nile tilapia were reared in twelve 200-L tanks for 63 days with 12 fish (body weight 38 g/fish at start) per tank. Two temperatures (22 or 30°C) and two color combinations (yellow and red each) for a two-component diet containing 30% (low) and a 38% (high) crude protein content based on dry matter were used. High water temperature (30 vs. 22°C) resulted in a significantly higher feed rate (1.93 ± 0.123 and 1.26 ± 0.100%, respectively), body weight gain (39.3 ± 4.29 and 4.75 ± 0.66 g, respectively), final body weight (70.3 ± 9.31 and 43.0 ± 7.49 g, respectively), and feed efficiency (55.4 ± 6.09 and 14.6 ± 2.86%, respectively), as well as protein efficiency ratio (1.687 ± 0.186 and 0.450 ± 0.087, respectively), regardless of color codes. No significant differences of color codes on growth parameters, body composition, and fatty acid profile were seen. Higher water temperature (30 vs. 22°C) only had an effect on percentage-specific fatty acids of total fatty acids of the whole body (biggest difference: C16:0, 20.5 ± 1.00 and 17.4 ± 1.11%, respectively). Therefore, water temperature clearly influences growth and fatty acid composition of the body.     

饲料中添加木聚糖酶对尼罗罗非鱼生长性能的影响

以尼罗罗非鱼(Tilapia nilotica)为试验对象,初始平均体重为(106.16±16.77)g,小麦基础饲料为对照,小麦基础饲料中分别添加不同水平的木聚糖酶(0.05%,0.10%,0.15%),75 d后测定其增重率、内脏指数、肝胰脏指数、肠道指数、表观消化率及肌肉营养成分。结果表明,对照组尼罗罗非鱼的增重率为258.24%,0.05%和0.10%组的增重率较对照组分别提高8.29%和17.45%(P<0.01)。对照组肠道指数和肝胰脏指数分别为1.90和2.82,0.05%组的肠道指数显著低于对照组(P<0.05),0.10%组极显著低于对照组(P<0.01)。0.05%,0.10%和0.15%组的肝胰脏指数分别比对照组降低14.54%,27.30%和12.06%(P<0.01)。对照组饲料干物质和总糖表观消化率分别为67.35%和61.48%。0.05%,0.10%和0.15%组的干物质消化率分别比对照组提高7.69%(P<0.05),11.00%(P<0.01)和2.87%(P<0.05)。3个试验组的总糖表观消化率均极显著高于对照组(P<0.01)。0.05%和0.10%组肌肉粗蛋白含量分别显著(P<0.05)、极显著高于对照组(P<0.01)。0.05%和0.10%组肌肉粗脂肪含量分别比对照组提高14.43%和33.89%(P<0.01)。0.05%,0.10%和0.15%组试验鱼肌肉中粗灰分含量分别比对照组提高4.11%,7.54%和2.77%(P<0.01)。0.05%,0.10%和0.15%组肌肉总钙含量分别比对照组提高19.70%,25.76%和15.15%(P<0.01),总磷含量分别比对照组提高4.78%,3.83%和3.83%(P<0.01)。0.05%和0.10%组试验鱼肌肉水分含量极显著低于对照组(P<0.01)。因此,本研究结论:在含50%小麦的基础饲料中适量添加木聚糖酶,可以提高尼罗罗非鱼的生长性能,其适宜添加水平为0.10%。     

低磷加植酸酶日粮不同钙磷比对生长猪生产性能和血清学指标的影响

试验选择90头初始体重20~30 kg的长×大二元杂交猪,随机分为5个处理(4个试验组和1个对照组),每个处理3个重复,每个重复6头猪,公母各占一半,研究低磷加植酸酶日粮不同钙磷比对生长猪生长性能和血液指标的影响。结果表明:钙总磷比值在1.4~1.0∶1时,生长猪的生产性能效果最好,日增重、日采食量分别比对照组提高8.4%,10.8%,统计分析差异显著(P<0.05);钙总磷比为1.4∶1时血清学指标最佳。     

日本鳗鲡仔鱼的开口饵料和行为特征

在连续多年日本鳗鲡人工繁殖实验的基础上,研究了不同饵料对日本鳗鲡仔鱼存活率的影响,并记录了仔鱼的运动特征和摄食行为。结果显示,与对照组(不投饵)相比,投喂以鲨鱼卵、磷虾提取液为基础的饵料和以鲨鱼卵、海蜇匀浆液为基础的饵料以及微绿球藻液均提高了日本鳗鲡仔鱼的存活率,仔鱼发育至柳叶鳗前期阶段;而投喂以鲨鱼卵、卤虫匀浆液为基础的饵料和以卤虫匀浆液、磷虾提取液为基础的饵料,以及轮虫、海带+龙须菜匀浆液或海蜇以及发酵鲨鱼肉,均降低日本鳗鲡仔鱼的存活率。实验同时还研究了日本鳗鲡仔鱼的主动摄食行为,摄食时仔鱼先用吻端反复多次触碰食物,然后张开下颌咬食,证实了日本鳗鲡早期仔鱼的摄食方式是触碰后咬食。     

三种饲料对异色瓢虫和龟纹瓢虫的饲喂效果

比较了3种饲料（米蛾卵、赤眼蜂蛹和桃蚜）对异色瓢虫和龟纹瓢虫发育和生殖力的影响，在瓢虫生长发育全过程中，分别用3种饲料饲养的结果表明，取食米蛾卵的两种瓢虫在低龄幼虫期即全部死亡；取食赤眼蜂蛹或桃蚜的瓢虫65.2%-84.6%均能羽化成虫,性比无差异；但取食赤眼蜂蛹的瓢虫，其幼虫和蛹的发育历期较取食桃蚜的显著延长，羽化的成虫体重也显著较轻，在瓢虫不同生长发育期（幼虫期和成虫期）喂饲不同饲料，对成虫产卵能力有明显的影响：幼虫期用赤眼蜂蛹、成虫期用赤眼蜂蛹或米蛾卵作饲料的瓢虫都不能产卵；幼早期用桃蚜、成虫期用赤眼蜂蛹或米蛾卵作饲料的亦不能产卵；幼虫期用赤眼蜂蛹、成虫期用桃蚜作饲料的瓢虫能产少量的卵（221粒）；幼虫期和成虫期全部用桃蚜作饲料产卵较多（404粒）。研究表明，米蛾卵不适于饲养这两种瓢虫；桃蚜饲养瓢虫的效果最好；桃蚜饲养瓢虫的效果最好；桃蚜供应不足时，在瓢虫幼虫期可适当用赤眼蜂蛹作为补充饲料。     

入侵云南草地贪夜蛾种群对5种常用Bt蛋白的敏感性评价

草地贪夜蛾Spodoptera frugiperda(J. E. Smith)是原分布于美洲大陆热带和亚热带地区的一种重要玉米害虫。在当地,种植抗虫转基因玉米是防控草地贪夜蛾危害的主要手段。该虫于2019年1月入侵我国云南省,为明确入侵我国云南的草地贪夜蛾种群对常用Bt蛋白的敏感性水平,本文通过饲料表面涂抹法测定了瑞丽草地贪夜蛾幼虫对Cry1Ab、Cry1Ac、Cry1F、Cry2Ab以及Vip3A等5种Bt蛋白的敏感性。结果表明:几种常用Bt蛋白对瑞丽草地贪夜蛾致死作用顺序为Vip3A>Cry1Ab>Cry1F>Cry2Ab>Cry1Ac,对草地贪夜蛾抑制生长发育的顺序为Cry1Ab>Cry1F>Vip3A>Cry1Ac>Cry2Ab。此外,与美国相对敏感种群比较,云南瑞丽草地贪夜蛾种群对Cry1Ab、Cry1Ac、Cry1F、Cry2Ab和Vip3A的敏感性指标在0.28～3.76之间,表明该入侵种群对此5种Bt蛋白均未产生抗性。此研究可为将来建立以转Bt基因玉米作为防控草地贪夜蛾的技术体系提供依据。     

新疆木垒波斑鸨生态学研究初报

1997年至 2 0 0 0年 ,作者等在新疆准噶尔盆地东部木垒县境内开展了波斑鸨 (Chlamydotisundulata)的生态学研究工作。研究内容涉及栖息地 ,种群数量和密度 ,巢与卵 ,筑巢成功率和孵化率 ,食性 ,迁徙。研究结果表明 ,波斑鸨多在植被盖度 ,高度和草本植物丰富度较低的地带繁殖栖息 ;研究区内约有成年波斑鸨 2 5 1- 2 93只 ,平均密度为 0 .0 838只 /km2 ;从 1998年至 2 0 0 0年 ,平均巢卵数分别为 :3.9± 0 .8,3.7± 0 .9和 3.0± 0 .9。孵化成功率为 0 .83～ 1。营巢成功率为 0 .2 5～ 0 .775 ;波斑鸨以多种植物和无脊椎动物为食 ,其中猪毛菜 (Salsolaarbuscula)是一类重要的食物 ;波斑鸨多在 9月中至 10月中开始秋季迁飞 ,平均迁徙天数为 2 4± 17天 ,飞越 34 0 0 - 470 0km ,在伊朗、印度和巴基斯坦越冬     

饲喂高蛋白日粮对雏鹅血清尿酸水平、肝脏和肾脏超微结构及ABCG2表达的影响

通过建立雏鹅高尿酸血症模型,研究高蛋白日粮对雏鹅血清尿酸水平、肝脏和肾脏超微结构及AB-CG2表达的影响.超微结构观察发现,对照组(CP)肝脏和肾脏细胞器结构完好,高蛋白1组(HP1)、高蛋白2组(HP2)肝脏部分线粒体开始出现肿胀、空泡变性,内质网肿胀消失,糖原减少.肾脏细胞部分线粒体开始出现肿胀、空泡变性,核膜间隙...