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121.
122.
A 50‐day feeding trial was conducted to examine the effects of dietary protein and lipid levels on growth, feed utilization, body composition and swimming performance of giant croaker, Nibea japonica. Fish (initial body weight 44.6 g ind−1) were fed ten test diets which were formulated at 5 crude protein levels (360, 400, 440, 480 and 520 g kg−1) and 2 crude lipid levels (90 and 150 g kg−1). In addition, a raw fish diet (fillet of small yellow croaker) served as the reference. The weight gain (WG) increased, whereas the feed intake (FI) and feed conversion ratio (FCR) decreased, with increasing dietary protein level from 360 to 520 g kg−1. At the same dietary protein level, no significant difference was found in the WG between fish fed the diets containing 90 or 150 g kg−1 crude lipid. Fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid exhibited higher WG, nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) but lower nitrogen wastes output (TNW). At the end of the feeding trial, the hepatosomatic index (HSI) and viscerosomatic index (VSI) decreased, whereas the body protein content increased, with increase in dietary protein level. The body lipid content was higher in fish fed at the 150 g kg−1 lipid level than in fish fed at the 90 g kg−1 lipid level. No significant difference was found in the maximum sustained swimming speed (MSS) between fish fed at different dietary protein and lipid levels. The WG, NRE, ERE and condition factor (CF) were higher, whereas the FI, FCR, HSI, VSI and TNW were lower, in fish fed the raw fish diet than in fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. No significant difference was detected in the MSS between fish fed the raw fish diet and diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. The results of this study suggest that the suitable dietary crude protein and crude lipid levels are 480 g kg−1 and 90 g kg−1 for giant croaker reared in net pens. 相似文献
123.
全面论述了甘肃白水江国家级自然保护区大熊猫的调查、研究历史,有关大熊猫的研究成果和进展情况,对今后大熊猫研究发展所面临的问题和计划提出了相应措施和对策。 相似文献
124.
蒲苇、花叶芦竹和芦苇是目前国内园林应用较为广泛的观赏草。由于同科,生物学特征有许多相似之处,加之科普认知、市场误导等的影响,使3者在行业内外造成了名实混淆的现象。该文通过文献查阅和实践调查,认为"银芦"、"意大利芦苇"应归始正名为蒲苇和花叶芦竹。 相似文献
125.
巴山木竹是大熊猫的主食竹种之一,具有较高的经济价值。文章从巴山木竹的生物学特性、与大熊猫的相互关系、营养成分和开发利用等方面,对巴山木竹的研究现状进行了分析和总结,提出了以无性系种群生态学、分子水平遗传多样性和"3S"技术的运用为代表的巴山木竹研究的新方向。 相似文献
126.
《北京林业大学学报》2012,34(1)
为从理论上研究"森林—竹子—大熊猫"三位一体的保护栖息地理念,考虑了竹子开花的影响,把竹子和森林分成两个阶段,建立了一个描述"森林—竹子—大熊猫"的非线性动力系统。利用Mawhin重合度理论可以证明此系统存在一个周期解,利用计算机数值模拟画出了此动力系统的周期解随时间的变化规律和相图。数值模拟显示脉冲的影响非常复杂,进一步研究还发现此模型存在一种新的混沌奇怪吸引子。讨论了得到的周期解和混沌奇怪吸引子的这些理论成果的生态意义。通过严谨的数学论证过程,证明了大熊猫栖息地的大熊猫、森林、主食竹是一个稳定的平衡系统这一结论,对大熊猫栖息地及其他类似濒危物种栖息地保护具有一定的指导意义。 相似文献
127.
Stahl M Osmann C Ortmann S Kreuzer M Hatt JM Clauss M 《Journal of animal physiology and animal nutrition》2012,96(5):818-824
Giant anteaters (Myrmecophaga tridactyla) are among those mammals for which a particularly low metabolism has been reported. In order to verify presumably low requirements for energy, we used eight anteaters (two males, six females; aged 1-14 years; body mass between 46 and 64 kg) in a total of 64 individual trials, in which a variety of intake levels was achieved on various diets. Digestible energy (DE) intake was quantified by measuring food intake and faecal excretion and analysing representative samples for gross energy, and animals were weighed regularly. Maintenance DE requirements were calculated by regression analysis for the DE intake that corresponded to zero weight change. Differences between individuals were significant. Older anteaters (n = 3 animals aged 12-15 years in 29 trials) had lower relative requirements than younger ones (n = 5 animals aged 1-7 years in 35 trials); thus, giant anteaters resemble other mammals in which similar age-specific differences in energy requirements are known. However, estimated maintenance requirements were 347 kJ DE/kg(0.75)/day in the anteaters, which is low compared to the 460-580 kJ DE/kg(0.75)/day maintenance requirements of domestic dogs. The lack of knowledge that metabolic requirements are below the mammalian average could make species particularly susceptible to overfeeding, if amounts considered adequate for average mammals were provided. Non-scientific reports on comparatively fast growth rates and high body masses in captive giant anteaters as compared to free-ranging animals suggest that body mass development and feeding regimes in captivity should be further assessed. 相似文献
128.
为了解短期饥饿对杂交石斑鱼(Epinephelus fuscogutatus♀×E.polyphhekadion♂)幼鱼消化酶活性和血清生理生化指标的影响,对杂交石斑鱼幼鱼进行短期饥饿处理(0 d、5 d、10 d、15 d),分别为S0组、S1组、S2组和S3组,并以S0组为对照组。结果表明,随着饥饿时间的延长,各种消化酶活性呈下降趋势,淀粉酶活性呈先上升后下降趋势。血清碳水化合物、胆固醇、甘油三酯、总蛋白、白蛋白等生化指标在饥饿前期显著降低(P<0.05),随后维持在相对稳定的水平。AST、ALT、ALP活性呈“下降-上升-下降”趋势。分析表明,在短期饥饿过程中,杂交石斑鱼幼鱼早期主要消耗碳水化合物和脂肪物质,后期主要以蛋白质代谢能量来维持生命活动,短期饥饿并没有对杂交石斑鱼造成不可逆转的肝脏损伤。 相似文献
129.
Reasons for performing study: Multinucleated histiocytic giant cells (MHGC) are seen frequently in skin‐biopsy specimens from horses with inflammatory dermatoses. However, the prevalence, number and morphological types of these cells have not been reported. Objective: To determine the prevalence, number and morphological types of MHGC in equine inflammatory dermatoses, and the association of these cells with specific conditions. Methods: Skin‐biopsy specimens from 335 horses with inflammatory dermatoses and from 27 horses with normal skin were evaluated for the prevalence, number and morphological types of MHGC. Results: The prevalence and number of MHGC were greater in granulomatous dermatoses than in nongranulomatous dermatoses. Infectious and noninfectious dermatoses were not different in terms of prevalence or morphological types of MHGC. Foreign‐body MHGC were the predominant type in almost all cases. MHGC were not seen in normal skin. Conclusions: MHGC are seen in a wide variety of equine inflammatory dermatoses, especially those that are granulomatous. Number and morphological types of MHGC are of no apparent diagnostic significance. Potential relevance: MHGC are frequently present in a wide variety of inflammatory dermatoses in the horse. Because the prevalence, number and morphological types of MHGC are of minimal diagnostic significance, special stains and tissue cultures are necessary to confirm specific diagnoses. 相似文献
130.