Photosynthetic bicarbonate utilization by a terrestrial cyanobacterium, Nostoc flagelliforme (Cyanophyceae)

The photosynthetic characteristics of the terrestrial cyanobacterium, Nostoc flagelliforme, after complete recovery by rewetting, was investigated to see whether it could use bicarbonate as the external inorganic carbon source when submerged. The photosynthesis-pH relationship and high pH compensation point suggested that the terrestrial alga could use bicarbonate to photosynthesize when submerged. The photosynthetic oxygen evolution rates were significantly inhibited in Na+-free and Na+ + Li+ media but were not affected by the absence of Cl-, implying that the bicarbonate uptake was associated with Na+/HCO3- symport rather than Cl-/HCO3- exchange system.

Growth and feed utilization in two strains of gibel carp, Carassius auratus gibelio: paternal effects in a gynogenetic fish

Gibel carp (Carassius auratus gibelio Bloch) is a natural gynogenetic fish which requires sperm of the same or related species to activate egg development. The eggs of one gibel carp were divided into two batches. One batch was 'fertilized' with sperm from gibel carp (strain DD), and the other 'fertilized' with sperm from red common carp (Cyprinus carpio red variety) (strain DR). The juveniles were transferred to the laboratory 36 days post-hatch. Triplicate groups of each strain were fed a formulated diet at either 3% or satiation ration for 8 weeks. At both the restricted and satiation rations, specific growth rate was significantly higher in strain DR than in strain DD. At the 3% ration, there was no significant difference in feeding rate or feed conversion efficiency between the two strains. At the satiation ration, strain DR had a significantly lower feeding rate but higher feed conversion efficiency than strain DD. At the satiation ration, strain DR had a significantly lower intake protein, but higher recovered protein than strain DD. There was no significant difference in faecal protein loss between the two strains. At the 3% ration, strain had no significant effects on intake protein, faecal protein or recovered protein. Neither faecal energy loss nor recovered energy was affected by strain or ration. At both the 3% and satiation ration, final body contents of dry matter and lipid were significantly lower in strain DR than strain DD, while there was no significant difference in protein and energy content between the two strains at either ration level. The results suggested that gibel carp 'fertilized' with sperm of common carp grew faster than those 'fertilized' with sperm of gibel carp through increased feed conversion efficiency and protein retention.

Utilization of several plant proteins by gibel carp (Carassius auratus gibelio)

Six isonitrogenous (gross protein content 35%) and isoenergetic (gross energy content 17 kJ g(-1)) diets were formulated to investigate the effects of inclusion of plant proteins on the gibel carp (Carassius auratus gibelio L.). The plant proteins tested were: soybean cake (SBC), potato protein concentrate (PPC), peanut cake (PNC), cottonseed cake (CSC) and rapeseed cake (RSC). Fish meal (FM) was used as control. In each diet, 27% of the protein was supplied by fish meal, and the rest supplied by the plant protein tested. Each diet was fed to three groups of gibel carp for 8 weeks in a recirculation system. Specific growth rate (SGR) in fish fed the control diet was significantly higher than those in the other groups, and SGR in fish fed the PPC was significantly lower than in fish fed other plant proteins. There was no significant difference in SGR among the other groups. Feeding rates were ranked in the order: RSC > CSC > FM > PNC > SBC > PPC. Conversion efficiency was highest in groups fed FM, SBC and PNC, followed by groups fed CSC and RSC, and was lowest in the group fed PPC. The fish fed PPC showed lower protein retention than those fed FM and SBC. FM showed highest energy retention while PPC showed lowest, There was no significant relationship between SGR and intake of digestible protein (g g(-1) day(-1)), digestible lysine (g g(-1) day(-1)), digestible methionine (g g(-1) day(-1)) or digestible total essential amino acids (g g(-1) day(-1)), suggesting that the differences in SGR could not alone account for any of these variables.

Compensatory growth, feed utilization and activity in gibel carp, following feed deprivation

Following a period of food deprivation, gibel carp compensated for growth through increased feed intake and conversion efficiency, but increased conversion efficiency was not achieved by increasing digestibility or reducing activity. (C) 2000 The Fisheries Society of the British Isles.

Growth and feed utilization by F-4 human growth hormone transgenic carp fed diets with different protein levels

The F-4 generation of human growth hormone (hGH) transgenic red common carp Cyprinus carpio had significantly higher growth rates than the non-transgenic controls. Protein and energy intakes were significantly higher in the transgenic carp than in the controls fed the 20% protein diet, but were not different between the two strains fed diets with 30 and 40% protein. Faecal protein loss, as a proportion of protein intake, was significantly lower in the transgenics than in the controls fed diets with 20 and 30% protein, but was not different between the two strains Fed diet with 40% protein. Faecal energy loss, as a proportion of energy intake, was significantly lower in the transgenics than in the controls fed diet with 20% protein, but was not different between the two strains fed diets with 30 and 40% protein. Recovered protein, as a proportion of protein intake, was significantly higher in the transgenics than in the controls fed all diets, whereas recovered energy was significantly higher in the transgenic fish fed the 40% protein diet. For fish fed each diet, the transgenics had significantly higher body contents of dry matter and protein, but lower contents of lipid than the controls. It was concluded that transgenics were more efficient in utilizing dietary protein than the controls. it a lower dietary protein level; transgenics achieved higher growth rates mainly by increasing feed intake; at higher levels of dietary protein, transgenics achieved higher growth rates mainly through a higher energy conversion efficiency. (C) 1998 The Fisheries Society of the British Isles.

Effect of feeding strategy and carbohydrate source on carbohydrate utilization by white sturgeon (Acipenser transmontanus) and hybrid tilapia (Oreochromis niloticus X O-aureus)

Two 8-week growth trials were conducted to determine the effect of continuous (CF) versus 2 meals day(-1) (MF) feeding and 30% starch versus 30% glucose diets on the carbohydrate utilization of 9.0-g white sturgeon and 0.56-g hybrid tilapia. The two trials were conducted under similar conditions except that sturgeon were kept at 18.5 degrees C in a flow-through system and tilapia were kept at 26 degrees C in a recirculating system. Significantly (P less than or equal to 0.05) higher specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), body lipid content and liver glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activities were observed in the CF than MF sturgeon. Only SGR, FE and PER were higher in sturgeon fed the starch than the glucose diets. Only higher liver G6PDH and malic enzyme (ME) activities were observed in the CF than MF tilapia but higher SGR, FE, PER and liver G6PDH, 6PGDH and ME activities were observed in tilapia fed the starch diet than those fed the glucose diet. This suggested that carbohydrate utilization by sturgeon was more affected by feeding strategy whereas tilapia was more affected by carbohydrate source. Furthermore, white sturgeon can utilize carbohydrates better than hybrid tilapia regardless of feeding strategy and carbohydrate source.

滇南、滇东南黑长臂猿分布与数量及金平芭蕉河黑长臂猿栖息地选择与利用

长臂猿是现存最小的类人猿（俗称小猿），主要分布于东南亚的的热带雨林、季雨林及亚热带常绿阔叶林中，是典型的树栖灵长类动物。我国现有长臂猿3属5种，包括黑长臂猿(Nomascus concolor)、白颊长臂猿(N. leucogenys)、海南长臂猿(N. hainanus)、白掌长臂猿(Hylobates lar)和白眉长臂猿(Hoolock hoolock)。其中黑长臂猿是主要分布于我国云南省境内的一种长臂猿，在国外仅在越南北部和老挝西北部局部地区分布，越南北部的数量不足100只，老挝目前仅发现9群。 滇南、滇东南曾是黑长臂猿广泛分布的地区之一。为掌握该地区近年黑长臂猿分布及种群数量现状，从2003年7月～2004年12月，利用访问调查及利用鸣声定位法对该地区进行了调查。调查结果显示，在云南境内，近40 000 km2的范围内，黑长臂猿在红河以东可能已消失，而红河以西亦仅发现4～7个种群，且孤立分布于3个地区（金平芭蕉河2群6只，金平西隆山1－2群，绿春黄连山1～3群，总计不超过25只），而在江城牛倮河自然保护区、马关古林箐自然保护区、麻栗坡老君山自然保护区及屏边大围山自然保护区可能已绝迹。滇南、滇东南黑长臂猿分布区缩小及种群数量剧减，主要与栖息地丧失及过度捕猎有关。 在长臂猿数量与分布调查的基础上，我们于2004年底确定了以金平芭蕉河黑长臂猿的一个群体为研究对象进行行为生态观察。通过扫描与瞬时取样法记录，结合生境调查及物候监测，对其游走行为及生境利用格局进行了比较和分析，主要结论如下：⑴家域大小（活动范围）不是限制长臂猿日活动距离及活动时间的主要原因；⑵日活动距离及移动时间均与温度呈正相关；⑶食物资源分布及斑块丰富度一定程度上决定了长臂猿对栖息地选择与利用方式；⑷长臂猿对陡坡与沟谷利用强度较高，与其主要行为表现（如;过夜点、休息点、取食点选择）有关；⑸长臂猿过夜点选择与食物资源分布、群体间关系及鸣叫点选择无关，而可能与天气和安全性因素有关；⑹果实树分布对取食点、休息点选择作用明显，而物候变化及食物可得性可能是影响长臂猿对栖息地利用季节性变化的主要原因；⑺在一定程度上，人为干扰只是在短时间内改变了长臂猿的活动路线或时间，而对其总体的生境利用策略并没有太大影响。食物资源的分布及季节性变化在长臂猿的游走行为及生境利用中均起到了重要作用。