水产动物肌酸营养的研究进展

肌酸(creatine,Cr)又称为N-甲基胍乙酸或肌肉素,是一种含氮有机酸。已广泛应用于改善人类健康,尤其用于促进肌肉生长。本文综述了肌酸在动物体内的合成、转运和储存规律,以及肌酸在肌肉和肝脏能量代谢中的作用,分析了饲料补充肌酸对动物生长和屠宰性能的影响,并从肌肉pH、系水力和肉色角度综述了肌酸对肉品质影响的研究进展,最后对肌酸在水产动物中的应用前景进行了展望,以期为肌酸在水产动物营养中的研究和在饲料中的应用提供参考。     

微生物基因组在生物质能源中的应用

生物质能源是一种可再生的绿色能源,介绍了生物质能源利用的现状及在生物质能源中微生物所起的作用,并指出微生物基因组及其相关技术在生物质能源发展中发挥的重要作用.     

香蕉茎秆废弃物综合利用研究现状与分析

介绍中国香蕉种植情况及香蕉茎秆废弃物状况,阐述国内外香蕉茎秆废弃物在纺织、造纸、饲料、肥料、能源等领域的利用状况及研究进展,结合香蕉产业发展现状分析香蕉茎秆废弃物综合利用过程中存在的问题,提出对策性建议。     

A dietary energy level of 14.6 MJ kg−1 and protein-to-energy ratio of 20.2 g MJ−1 results in best growth performance and nutrient accretion in silver barb Puntius gonionotus fingerlings

Five iso-nitrogenous (300 g protein kg⁻¹ diet) and iso-lipidic (80 g kg⁻¹ diet) semi-purified experimental diets with variable energy levels of 10.5 (D-1), 12.5 (D-2), 14.6 (D-3), 16.7 (D-4) and 18.8 (D-5) MJ kg⁻¹ diets were fed to Puntius gonionotus fingerlings (average weight 1.79 ± 0.02 g) in triplicate groups (15 healthy fishes per replicate) for a period of 90 days to assess the optimum dietary energy level and protein-to-energy ratio (P/E). Fifteen flow-through cement tanks of 100 L capacity with a flow rate of 0.5 L min⁻¹ were used for rearing the fish. Maximum specific growth rate, protein efficiency ratio, protein productive value, RNA : DNA ratio, whole body protein content, digestive enzyme activity and minimum feed conversion ratio was found in fish-fed diet D-3 with 14.6 MJ kg⁻¹ energy level. There were no improvements in all these parameters with the further rise in dietary energy level. Hence, it may be concluded that the optimum dietary gross energy level for maximum growth and nutrient utilization of silver barb is 14.6 MJ kg⁻¹ diet with a resultant P/E ratio of 20.2 g protein MJ⁻¹ diet, when the dietary protein and lipid are maintained at optimum requirement levels of 300 and 80 g kg⁻¹ diet, respectively, for this species.     

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.     

三疣梭子蟹胚胎发育过程中主要生化组成的变化及其能量来源

系统研究了三疣梭子蟹(Portunus trituberculatus)胚胎发育过程中胚胎体积、单卵干重、湿重、蛋白质、脂肪、碳水化合物的变化规律,探讨胚胎发育过程中能量来源和消耗规律。结果表明,三疣梭子蟹胚胎发育过程中,胚胎体积持续增加,由受精卵时的(24.5±1.72)×106μm3增加到孵化前的(39.2±2.8)×106μm3(P<0.01);胚胎体积增加主要发生在胚胎发育后期。胚胎发育过程中单卵中水分含量呈上升趋势(P<0.05),水分绝对量由受精卵的(19.88±1.65)μg上升到心跳期的(28.82±1.77)μg,单卵水分含量升高了44.97%,故单卵湿重显著上升(P<0.05)。整个胚胎发育过程中单卵干重下降了4.64%。胚胎发育过程中单卵中的蛋白质、脂肪下降显著,分别减少了(1.97±0.35)μg和(1.99±0.45)μg,脂肪含量下降幅度为50.48%,而蛋白质含量下降幅度为23.48%;三疣梭子蟹胚胎发育过程中能量主要由脂类提供(71.32±20.46)%,其次由蛋白质提供(27.13±4.29)%,脂类和蛋白质分别充当了不同胚胎时期的主要能量来源,胚胎中的能量消耗主要发生在卵裂期、原肠期和心跳期。     

短须裂腹鱼有氧游泳能力及其行为的实验研究

研究短须裂腹鱼的游泳能力、运动生理及游泳行为,为过鱼设施的设计提供参考依据。实验用15尾短须裂腹鱼于2013年7月中旬采自金沙江上游玛曲河河口处,体长(23.83±2.47)cm,体重(224.95±76.83)g。游泳能力测试装置采用丹麦Loligo Systems公司生产的大型游泳水槽。(1)短须裂腹鱼临界游泳速度为(75.04±7.6)cm/s、(3.17±0.42)BL/s;(2)运动耗氧率与游泳速度呈幂函数关系:MO2=100.00+42.61U1.81(R2=0.995,P0.001);单位距离耗氧率(COT)与游泳速度的关系也呈幂函数关系:COT=0.12U-1+0.04U1.02(R2=0.898,P0.001),最适游速Uopt=1.81 BL/s,COTmin=0.14 mg/(kg·m);(3)随着游泳速度的增加,尾摆幅度的变化不显著(P0.05),变化范围为0.17~0.26 BL、平均(0.21±0.02)BL,而尾摆频率和运动步长都呈线性增加的趋势。     

Temporal changes in plasma thyroid hormone,growth hormone and free fatty acid concentrations,and hepatic 5′-monodeiodinase activity,lipid and protein content during chronic fasting and re-feeding in rainbow trout (Oncorhynchus mykiss)

Temporal changes in growth, plasma thyroid hormone, cortisol, growth hormone (GH) and non-esterified fatty acid (NEFA) concentrations, hepatic T₃ content and hepatic 5-monodeiodinase activity were measured in rainbow trout (Oncorhynchus mykiss) subjected to a sustained fast for up to eight weeks, and during a four-week re-feeding period. The purpose of the study was to examine aspects of the endocrine control of energy partitioning processes characteristic of short-term (acute; fasting) and long-term (chronic; starvation) food-deprivation states in fish, and to explore the role of the thyroid hormones, cortisol and GH in the energy repartitioning that takes place during an acute anabolic (re-feeding) state following chronic food deprivation.Differences in growth rate between fed and fasted groups were evident after two weeks, but significant weight loss by the fasted groups was not evident until between four and six weeks into the fast. Hepatosomatic indices (HSIs) were significantly reduced in the fasted fish within seven days, and as early as two days in one study; recovery of the HSI in fasted fish was evident within three days of re-feeding. Liver protein content (expressed as % wet weight) was consistently depressed in the fasted fish in only one of the three studies. Liver total lipid content (expressed as % wet weight) was depressed in the fasted fish within two days of food deprivation. Because of the rapid and sustained decrease in the HSI of fasted fish, the hepatic total protein and lipid reserves, when considered on a body weight basis, were markedly lowered within the first few days of the fast. Plasma GH concentrations exhibited a bi-modal pattern of change, with a transient fall in levels, followed by a sustained increase in fasted fish. The indicators of interrenal activity were suggestive of a depressed pituitary-interrenal axis in fasted animals; plasma cortisol levels were elevated to levels of fed animals within one day of re-feeding. The indicators of thyroid hormone economy (plasma thyroid hormone levels, liver triiodothyronine content, hepatic 5-monodeiodinase (MD) activity, thyroid epithelial cell height) were similarly indicative of a depressed pituitary-thyroid axis in fasted animals, with recovery to levels of the fed animals within one week. Despite the compensatory changes in accumulation of reserves (as indicated by a compensatory increase in HSI), there were no apparent compensatory changes in any of the endocrine parameters evident during the re-feeding period.     

pH值和Ca~（2＋）浓度对日本沼虾生长和能量收支的影响

本文报道了不同ｐＨ值（６．５、７．５和８．５）和不同Ｃａ２＋浓度（３８．８．６１．１和７８．８ｐｐｍ）对日本沼虾生长和能量收支的影响。实验结果表明，ｐＨ值对该虾的生长有一定的影响，Ｃａ２＋和ｐＨ值在影响其生长的过程中可能有一定的交互作用。ｐＨ值和Ｃａ２＋对该虾生长的影响主要是通过影响其能量摄入量实现的。本实验条件下，该虾摄入的能量平均有１５．８％用于生长，１．８％作为粪便排出体外，其余用于呼吸和排泄。