Protein and Energy Metabolism of European Seabass (<Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>) Juveniles and Estimation of Maintenance Requirements

The present work aimed to study metabolic utilization of energy and protein by juvenile European seabass reared at 25 °C and to estimate maintenance requirements, based on indirect calorimetry and nitrogen excretion measurements. Duplicate groups of fish (IBW = 22 g) were fed a practical diet, for 28 days, at ration levels of 0, 0.25, 0.5, 1 and 1.5% of body weight. At the end of this period, oxygen consumption and ammonia nitrogen excretion were measured in fed and unfed fish. Weight gain linearly increased with ration level. Feed efficiency significantly increased with nitrogen intake up to 0.68 g N/kg/day. Nitrogen retention (% N intake) was positive at all feeding levels, being maximum at 0.5% BW and then decreased with increasing ration levels. There was negative energy balance at the lowest ration level and significantly increased at higher ration levels. Daily oxygen consumption (g/kg body mass) and ammonia excretion (mg N–NH₄/kg body mass) significantly increased with ration level. Heat production and heat increment of feeding (kJ/kg/day) remained low at low ration levels and significantly increased as ration level increased from 0.5 to 1.5% BW. Below maintenance, protein energy represented 34% of total energy expenditure and significantly increased to 49–56% above maintenance. Based on indirect calorimetry and ammonia excretion data, maintenance energy and protein requirements were estimated to be 56.8 kJ DE/kg/day and 1.15 g DP/kg/day, respectively. The efficiencies of energy and protein utilization were estimated to be 0.83 and 0.66, respectively.     

中草药对斑节对虾生长、饲料利用和肌肉营养成分的影响

研究了中草药对斑节对虾Penaeusmonodon(初始体重0.30g.尾-1)生长性能、饲料利用以及肌肉营养成分和氨基酸的影响。6种实验饲料(按顺序分别为1,2,3,4,5和6)中中草药的添加量分别为0,0.5,1.0,2.0,4.0和8.0g·kg-1饲料。除了饲料2之外,斑节对虾的成活率、饲料系数和蛋白质效率都显著(P<0.05)优于对照组(饲料1)。投喂饲料3的斑节对虾增重率与对照组相比,虽然统计学上不存在显著差异,但有较大幅度的提高。投喂添加中草药的饲料对斑节对虾肌肉的水分和蛋白质含量无显著影响,但脂肪含量明显下降。结果表明,斑节对虾饲料中添加适量的中草药能够促进生长、显著提高成活率和降低饲料系数,并改变斑节对虾肌肉中脂肪含量和氨基酸组成。     

Full-fat soybean meal in diets for Atlantic halibut: growth, metabolism and intestinal histology

Isonitrogenous and isocaloric diets containing 0, 18 or 36% toasted full-fat soybean meal (FFSM) were fed to Atlantic halibut. The diets were fed to five tanks of fish each for 34 days (period 1). Four tanks from each treatment were then retained in the growth experiment for a further 32 days (period 2), while the groups of fish from one tank from each of the 0 and 36% FFSM groups were split and transferred to two metabolism tanks each. The initial weight of the fish in the growth trial was 169 ± 1 g (mean ± SEM, n =12; weight range 89–253 g) and the final weight was 317 ± 5 g. There was no significant effect of dietary treatment on specific growth rate (range, 0.8–1.1% day⁻¹), feed consumption (0.5–0.7% body weight day⁻¹), feed efficiency (1.3–1.6 g wet gain g dry feed⁻¹), protein retention (48–55%) or energy retention (49–57%). The fat, protein and energy concentrations in the fish increased during the trial and were not affected by the diet. The hepatosomatic index in fish fed with 36% FFSM diet was significantly lower (1.7%) than in the other groups (2.2%) ( P  < 0.05). No differences in intestinal morphology were observed between dietary treatments and no pathological reactions were identified in any of the samples. In the metabolism trial, there were no significant differences in oxygen consumption or ammonia excretion between fish fed with 0 and 36% FFSM diets. In conclusion, up to 36% FFSM may be added to diets for Atlantic halibut without negative effects on growth, feed efficiency or intestinal morphology.     

畜禽粪污资源化利用模式能值评价与比较分析——以新疆呼图壁县为例

基于典型案例,采用能值分析法对沼气工程模式、生物有机肥生产模式和堆积发酵还田模式进行定量的能值评价、分析及比较。结果表明:三种模式从成本、生产效率、自我支持能力、处理废弃物能力、对环境的压力等方面来看效益都较好。但在系统自组织能力、可持续性方面,生物有机肥模式和堆积发酵还田模式效益均差、沼气工程模式效益最好。并认为应提高现有模式综合效益、探索多样化模式、沼气工程建设应考虑多种必要因素、应解决模式冬季运作问题。     

夜蛾黑卵蜂人工扩繁及应用研究进展

夜蛾黑卵蜂是多种鳞翅目害虫的重要卵寄生性天敌之一, 特别是对当前全球暴发的草地贪夜蛾有较好的控害效果。本文从生物防治的角度出发, 对草地贪夜蛾优势卵寄生天敌夜蛾黑卵蜂的生物学、人工扩繁以及在生产中的应用现状3个方面进行了梳理和归纳。     

略阳县五叶草莓种质资源调查与开发利用

为合理开发利用略阳县丰富的五叶草莓资源,本文对五叶草莓的种质资源分布状况进行了调查,发现略阳县五叶草莓主要有白果、粉果和红果3种类型,平均单果质量0.86~1.27 g,果实可溶性固形物含量7%~9.5%,果实不耐贮藏,主要分布在海拔916~1630 m的地区,当地市场销售价格20~80元/kg,此次调查可为五叶草莓资源的开发利用提供参考。     

番茄基因编辑研究进展和前景

介绍了基因编辑技术的发展和现状,并对该技术在番茄耐贮性和成熟调控、营养成分和果色、雄性不育和单性结实、逆境响应、株形、花形及野生种重新驯化等方面的研究进展进行了概述,梳理了基于CRISPR/Cas技术的单碱基编辑、DNA-free编辑及提高同源重组效率的技术创新及在番茄遗传改良和品种培育方面的应用前景和面临的挑战。     

临夏州畜禽养殖粪污资源化利用及对策建议

近几年,随着临夏州畜牧养殖业的快速发展,与之相伴的畜禽养殖粪污污染问题也成为临夏州现代畜牧养殖业绿色发展的制约因素,不仅导致环境的污染,也造成了资源的浪费,文章结合当地实际,为实现畜牧业绿色发展,就畜禽养殖粪污资源化利用提出建议及对策,供参考。     

武汉市规模猪场粪水资源化利用典型模式探析

为有效控制规模猪场生产中产生的粪水对环境的影响,加快推进规模猪场粪水资源化利用,促进一、二、三产业融合,文章立足于武汉市规模猪场粪水资源化利用实际,选取规模猪场粪水资源化利用典型模式进行分析,以期为提高规模猪场粪水资源化利用提供借鉴。     

Halophyte root powder: an alternative biofertilizer and carrier for saline land

ABSTRACT

The present investigation was based on the hypothesis that the endophytes residing in the roots of halophytes have better adaptation to saline conditions. Six halophytic herbs were collected from Khewra salt range (EC = 4.7 dS m^?1 and SAR = 25.7). From these herbs, root pieces of Cenchrus ciliaris were shade dried; finely ground to powder and three plant growth promoting rhizobacteria (PGPR), Bacillus cereus, Pseudomonad moraviensis, and Stenotrophomonas maltophilia, were isolated. Root powder in sterilized and unsterilized forms was added in the saline-sodic field on wheat and mixed with soil in pot experiment with induced NaCl (150 mM). Sterilized root powder increased organic matter NO₃-N and P contents of soil and leaves, fresh weight, sugar content, and yield attributes. The root powder application in unsterilized form significantly decreased EC, SAR, and Na content of field soil with concomitant increase in soil and leaves K, P, and NO₃-N. The farmer’s benefit was increased by 33% at yield. Root powder-induced salt tolerance was mediated by the PGPR (residing inside the root) through increased growth and better physiological adaptations. It is inferred that root powder harboring the PGPR may be an alternative to biofertilizer with longer shelf life and may also serve as carrier for the preparation of effective biofertilizer for saline land using other PGPR bio-inoculants.