MS-222在加州鲈鱼模拟运输中的麻醉效果

研究了加州鲈鱼(Micropterus salmoides)在10、20、30、40、50、60和70 mg/L的MS-222麻醉液中的麻醉效果,并在20 mg/L的MS-222麻醉液中研究了10、15、20和25℃水温对麻醉效果的影响,最后在20℃和20 mg/L的MS-222麻醉液中进行了麻醉模拟运输试验。麻醉试验结果表明:随着MS-222浓度的增加,进入相同麻醉期的时间缩短,完全复苏的时间延长。10~20 mg/L的MS-222适于加州鲈鱼的麻醉运输。麻醉时间随着水温的降低而缩短,复苏时间随着水温的降低而增加。20~25℃水温适于加州鲈鱼的麻醉运输。麻醉模拟运输试验结果表明:运输17 h存活率100%,运输24 h存活率降到70%。麻醉的鱼复苏时间随运输时间的增加而增加。麻醉运输后,肌肉中糖元含量下降,乳酸含量上升。血清皮质醇变化差异不显著但都显著高于基础组(P0.05)。天冬氨酸氨基转移酶(AST)、尿素(UREA)、乳酸脱氢酶(LDH)在运输前10 h差异不显著之后显著升高(P0.05),葡萄糖(GLU)随运输时间的增加而增加。     

Potential of meat meal to replace fish meal in extruded dry diets for barramundi, Lates calcarifer (Bloch). II. Organoleptic characteristics and fatty acid composition

The organoleptic quality of barramundi fed for 66 days on pelleted diets containing varying amounts of fish meal and meat meal was determined in two experiments (E1 and E2). Each compared four diets: a 430 g kg^?1 crude protein (CP) control diet (containing 35% Chilean anchovy fish meal); two diets containing high inclusions (40% or more) of meat meal; and a proprietary barramundi diet. In E1, the two meat meal diets contained 10% Chilean fish meal whereas the two meat meal diets in E2 had no marine protein ingredients. Panellists identified and rated the colour of flesh, and scored odour, flavour and texture characteristics and overall liking on structured graphic line scales (0–100). Fish fed the high‐meat meal diets were sweeter and firmer than those fed the high‐fish meal control diet in E1 (P < 0.05). Scores for fishy flavour were also highest for the meat meal diets and lowest for the proprietary diet. In both E1 and E2, scores were high (> 60) for overall liking and low (< 10) for undesirable odours and tastes. Exclusion of all sources of marine protein from the diet in E2 did not detract from the sensory value of the fish. The influence of diet on the fatty acid profile of the fish was examined in E2. Compared with fish fed the control diet, the neutral lipid fraction of those fed the meat meal diets had higher proportions of saturated and short‐chain monounsaturated fatty acids at the expense of longer chain fatty acids, especially 22:6n‐3. Polar lipids showed only subtle dietary effects, which were confined to the long‐chain unsaturated fatty acids.     

Ontogenetic diet shifts of age-0 smallmouth bass (Micropterus dolomieu Lacepède) in the New River, West Virginia, USA

Larval and juvenile smallmouth bass (Micropterus dolomieu Lacepède; 8.5–85.0 mm total length (TL)) were collected from 2 sites in the New River, West Virginia, in the late spring and early summer to document diet shifts during early ontogeny. The first foods of smallmouth bass (TL = 9 mm) were primarily Chironomidae and microcrustaceans (primarily Copepoda). Other aquatic insects, primarily Ephemeroptera, became more abundant in the stomachs as TL increased. A shift in the proportions and types of prey consumed began at approximately 15 mm TL and was primarily attributed to fin development and increased mouth size. Foraging success, measured by number of prey per stomach, stomach fullness, and average prey volume was lower for first-feeding smallmouth bass than for later life stages. Mouth width appeared to restrict the size of prey consumed by larval smallmouth bass, but the maximum prey width never approached the mouth width for fish longer than 35 mm TL.     

Physical activity and behavior of a centrarchid fish, Micropterus salmoides (Lacépède), during spawning

Abstract – The spawning behavior of male and female largemouth bass Micropterus salmoides (Lacépède) was studied in central Illinois during the spring of 1998 to examine patterns of muscular activity associated with different spawning related behaviors and to evaluate whether electromyogram (EMG i ) telemetry could be used to detect spawning activity. Fish were implanted with EMG i transmitters (8 females, 16 males) on April 7, prior to the initiation of spawning, and were released in four 0.10-ha earthen research ponds. Continuous EMG i records, underwater videography and additional visual observations for one pair of EMG i tagged fish were collected throughout the entire spawning event, allowing us to quantify behavioral correlates of physical activity. Male EMG i activity patterns were only correlated with female patterns during courting and periods of male aggression toward the female. Overall, EMG i activity was highest for the female during shuddering (gamete deposition), whereas male EMG i activity was similarly high during periods of nest excavation, shuddering and post-spawn parental care activities. During spawning, female EMG i activity was positively correlated to shuddering. Average daily EMG i activities for females peaked on the day of spawning. As a result of their engagement in parental care activities, male activity continued to rise even after spawning was completed. EMG i telemetry appears to be a useful technique for monitoring the reproductive activity of largemouth bass, especially in areas of high cover or turbid water or during low light conditions. This technology permitted us to quantify and contrast the activity patterns associated with different spawning related activities, information that will be required to construct accurate, gender-specific bioenergetics models for this species.     

加州鲈卵泡抑素cDNA的克隆、分析和原核表达

卵泡抑素是TGF-β超家族中一些成员的抑制蛋白，具有促肌肉生长的作用。采用RT-PCR和RACE技术从加州鲈成鱼卵巢总RNA中扩增得到卵泡抑素cDNA，序列分析结果表明，加州鲈卵泡抑素cDNA全长1444bp，包括开放阅读框966bp，5¢非编码区82bp，3¢非编码区359bp。该基因编码321个氨基酸，其中信号肽31个氨基酸，成熟肽290个氨基酸，成熟蛋白由四个功能区组成，分别为：N-domain、Domain Ⅰ、Domain Ⅱ和Domain Ⅲ，其中N-domain具有与TGF-β超家族中一些成员特异性结合的结构，可抑制这些蛋白发挥作用。将加州鲈卵泡抑素氨基酸序列与红鳍东方鲀、草鱼、斑马鱼、大西洋鲑和斑点叉尾鮰比较，同源性分别为97％、89％、88％、88％和70％，其中N-domain氨基酸序列的保守性更高一些，与红鳍东方鲀、草鱼、斑马鱼、大西洋鲑、斑点叉尾鮰、非洲爪蟾、人、猪、大鼠、鸡的相比较，同源性为75%～100％。为获得重组卵泡抑素蛋白，将成熟肽cDNA插入表达载体pET-32a(+)，转化大肠杆菌，IPTG诱导表达，SDS-PAGE检测，结果检测到一分子量约52kD的特异蛋白带，与预期大小一致，Western blot检测到表达产物表明成功获得了卵泡抑素的融合蛋白。加州鲈卵泡抑素cDNA序列和重组蛋白的获得为进一步研究鱼类卵泡抑素的促肌肉生长奠定了基础。     

Community-level impacts induced by introduced largemouth bass and bluegill in farm ponds in Japan

Largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus have been introduced into many countries and have become cosmopolitan exotic species. However, only a few studies show their impact on introduced communities. To investigate their impact, we performed natural snapshot experiments in 15 farm ponds in Saitama prefecture, eastern Japan. We selected 10 and 5 small ponds in similar environmental conditions, but with and without exotics, respectively. The numbers of fish, crustaceans, and nymphal odonates were smaller in ponds where exotics were found and some species were considered to be locally extinct in several ponds. On the other hand, the numbers of benthic organisms, i.e. tadpoles, chironomids, chaoborids, and Oligochaeta were more abundant in ponds with exotics. These two groups of organisms were separated clearly on the first axis of DCA, which indicats that this difference was mainly induced by bass predation. This result suggests a trophic cascade in which top-down effects induced by exotics propagated to fish, crustaceans, and nymphal odonates directly and to some benthic organisms indirectly. Therefore, when one is to conserve native organisms, attention should be paid not only to direct negative effects, but also to indirect effects propagating to various trophic levels. Because farm ponds are typical Japanese small lentic systems having rich biodiversities and bass and bluegill have been shown to change farm pond communities widely, conservational treatments including eradication of exotic fish should be conducted immediately.     

Use of tag data to compare growth rates of Atlantic coast striped bass stocks

Migratory stocks of Atlantic coast striped bass, Morone saxatilis (Walbaum), range primarily from North Carolina (NC) northward to Canadian waters. Between 1986 and 2000, 267 045 wild striped bass were tagged and released from NC to Massachusetts as part of the Cooperative Striped Bass Tagging Program. Direct measurements of growth of individual fish can be obtained from tag data and are useful for understanding the dynamics of fish populations. Growth rates from regressions of length‐increment vs. time‐at‐liberty were estimated for striped bass tagged and released in three southern states [NC, Virginia (VA) and Maryland (MD)] and three northern states (New Jersey, New York and Rhode Island). Striped bass tagged in waters of northern states grew faster (significantly steeper regression slopes) than those tagged in southern areas. Migratory patterns, stock mixing, and unmeasured biotic and abiotic influences on growth precluded conclusions that observed growth patterns are stock‐specific. These results, however, indicate latitudinal differences in growth rates, and should be considered in future research and management of Atlantic coast striped bass.