共查询到20条相似文献，搜索用时 375 毫秒
1.
Dualistic feeding pattern of Nile tilapia (Oreochromis niloticus,L.) reared under different self‐feeding system conditions 
下载免费PDF全文
下载免费PDF全文 Nile tilapia (Oreochromis niloticus) is one of the most important cultured species worldwide. The research aims to clarify the feeding characteristics, such as daily feeding pattern of Nile tilapia using a self‐feeding technique. The feeding pattern was conducted under two rearing conditions, indoor treatments under a controlled light regime (LD 12:12) and constant water temperature (25°C), and outdoor treatments under natural conditions which consisted of duplicate trials with two periods each. The outdoor treatment was carried out from early summer through late autumn in Mie, Central Japan. Daily self‐feeding activity of Nile tilapia in indoor treatments was nearly daytime feeding pattern, synchronizing with the given photoperiod (24 hr). However, the self‐feeding activity in the outdoor experiments from early summer to early autumn was almost daytime feeding pattern, but it became less clear and shifted to a nighttime feeding profile in late autumn. The results revealed that Nile tilapia has a dualistic capacity for demand‐feeding both in light and dark phases. These results might have been caused by the seasonal change in light intensity and/or water temperature. Information obtained from the self‐feeding experiments enables us to identify the influence of environmental changes on the physiological condition of farmed fish through their expression of appetite. 相似文献
2.
3.
Timing to promote initial swimbladder inflation by surface film removal in Pacific bluefin tuna,Thunnus orientalis (Temminck and Schlegel), larvae 下载免费PDF全文
下载免费PDF全文 Michio Kurata Manabu Seoka Yasunori Ishibashi Tomoki Honryo Shigeru Katayama Kenji Takii Hidemi Kumai Shigeru Miyashita Yoshifumi Sawada 《Aquaculture Research》2015,46(5):1222-1232
This study investigated the optimal timing of day to promote initial swimbladder inflation (ISI) for improved Pacific bluefin tuna (PBT), Thunnus orientalis, larval survival. Larval swimbladder inflation frequency was compared based on three experiments using different time schemes of surface film removal (SFR) from 3 to 9 days post hatch (dph). SFR was conducted from 05:00 to 19:00 hours (light period: S.5–19), 19:00 to 05:00 hours (dark period: S.19–5), 08:00 to 19:00 hours (S.8–19) and the entire day (S.24) in Experiment 1; from 08:00 to 19:00 hours (S.8–19‐E2), 08:00 to 13:00 hours (S.8–13), 13:00 to 19:00 hours (S.13–19) in Experiment 2; and from 13:00 to 16:00 hours (S.13–16), 16:00 to 19:00 hours (S.16–19), 18:00–19:00 hours (S.18–19) in Experiment 3. The swimbladder inflation frequency at the experiment termination (9 dph) was significantly higher (P < 0.001) in S.24 (91.1 ± 5.7%), S.5–19 (92.2 ± 5.1%) and S.8–19 (93.3 ± 3.4%) than in S.19–5 (11.1 ± 5.1%) in Experiment 1, and remarkably higher in S.8–19‐E2 (81.7%) and S.13–19 (88.3%) than in S.8–13 (0.0%) in Experiment 2, and significantly higher (P < 0.001) in S.16–19 (84.4 ± 5.1%) and S.18–19 (70.0 ± 12.0%) than in S.13–16 (7.8 ± 3.9%) in Experiment 3. These results suggest that the optimal timing to promote larval ISI by SFR is a few hours before the end of light period (16:00–19:00 hours) from 3 to 9 dph. 相似文献
4.
Kang Liu Beiping Tan Wei Zhang Hongyu Liu Xiaohui Dong Qihui Yang Shuyan Chi Shuang Zhang Haitao Zhang 《Aquaculture Research》2019,50(8):2155-2169
5.
6.
Elangovan Prabu Nathan Felix Arumugam Uma Jayasimhan Praveenraj 《Aquaculture Nutrition》2020,26(2):568-578
An 8‐week feeding trial was conducted with extruded practical diets containing 320 g/kg of crude protein from plant‐based sources to determine the effects of L‐lysine on growth performances, muscle‐growth‐related gene (myoD, myogenine and myostatin) expression and haemato‐biochemical responses in juvenile genetically improved farmed tilapia (GIFT). Five isonitrogenous and isoenergetic diets were formulated to contain graded levels of lysine (14.3, 16, 17.5, 19 and 20.5 g/kg of diet). Each diet was randomly assigned to triplicate groups of 30 juvenile fish (5.2 ± 0.1 g), which were fed thrice a day (9:00, 13:00 and 17:00 hr). Maximum growth performances were observed in fish fed with lysine at 19 g/kg of diet. There was no significant (p > .05) effect on whole‐body composition and amino acids profile by dietary lysine supplementation. Significant (p < .05) changes were observed in relative expression of muscle‐growth‐related genes namely myoD and myogenine and in plasma metabolites by dietary lysine supplementation. In contrast, the relative expression of myostatin was not affected by dietary lysine supplementation. Broken‐line regression analysis and second‐order polynomial regression analysis of weight gain and N gain against dietary lysine levels showed that the dietary lysine requirement for juvenile GIFT tilapia was 18–18.3 g/kg of diet and 19.3–19.5 g/kg of diet, respectively. 相似文献
7.
8.
9.
Transcriptomic analysis reveals olfactory‐related genes expression in large yellow croaker (Larimichthys crocea) regulated by taurine: May be a good phagostimulant for all‐plant protein diets 下载免费PDF全文
下载免费PDF全文 Jiabao Hu Yajun Wang Qijun Le Na Yu Xiaohuan Cao Huakun Zheng Siwen Kuang Man Zhang Junyong Zheng Xiaokai Wu Jianbo Wang Shunshun Tao Xiaojun Yan 《Aquaculture Research》2018,49(2):1095-1104
10.
The Mediterranean spearfish (Tetrapturus belone) is one of the least‐studied istiophorid billfishes, with little known of its biology, ecology, and behavior. To assess the species’ movement and thermal niche, we analyzed telemetry data from, to our knowledge, the first and only Mediterranean spearfish ever outfitted with a pop‐up satellite archival transmitting tag. Throughout a 29‐day deployment during July and August 2015, the fish travelled in Italian waters of the Tyrrhenian and Ligurian Seas, spending on average 93% of each 24‐hr period above 30 m and exhibiting a diel activity pattern comprised of daytime vertical movement and nighttime near‐surface residency. The preferred thermal niche was 26–28°C, but the spearfish experienced temperatures as low as 14.2°C during descents. Vertical distribution was limited throughout the deployment with more time spent at depth in areas where the thermocline was comparatively deeper and weaker, consistent with habitat compression experienced by other billfishes. 相似文献
11.
Characterization of phenotype variations of luminescent and non‐luminescent variants of Vibrio harveyi wild type and quorum sensing mutants 下载免费PDF全文
下载免费PDF全文 Vibrio harveyi, a luminescent Gram‐negative motile marine bacterium, is an important pathogen responsible for causing severe diseases in shrimp, finfish and molluscs leading to severe economic losses. Non‐luminescent V. harveyi obtained by culturing luminescent strains under static and dark condition were reported to alter the levels of virulence factors and metalloprotease gene and luxR expression when compared to their luminescent variants. Presently, we conducted an in vitro study aiming at the characterization of virulence‐related phenotypic traits of the wild‐type V. harveyi BB120 strain and its isogenic quorum sensing mutants before and after switching to the non‐luminescent status. We measured the production of caseinase, haemolysin and elastase and examined swimming motility and biofilm formation. Our results showed that switching from the bioluminescent to the non‐luminescent state changed the phenotypic physiology or behaviour of V. harveyi resulting in alterations in caseinase and haemolytic activities, swimming motility and biofilm formation. The switching capacity was to a large extent independent from the quorum sensing status, in that quorum sensing mutants were equally capable of making the phenotypic switch. 相似文献
12.
Molecular cloning and characterization of p38 gene in the Chinese Mitten Crab,Eriocheir sinensis 下载免费PDF全文
下载免费PDF全文 p38 is an important component of the MAPK signaling pathways as a Ser/Thr protein kinase. We cloned the full length p38 (Es‐p38) cDNA sequence in Eriocheir Sinensis which contained a 1098‐nucleotide ORF that encoded a protein of 365 amino acids. Es‐p38 protein has a p38 MAPK functional domain (STKc_p38), it is a typical serine/threonine kinase and processes all p38 protein's conservative T‐G‐Y motif. Tissue expression of the Es‐p38 gene and expression during testis development stages were determined by quantitative real‐time PCR analysis. The results show that Es‐p38 gene is expressed in various tissues, but it expresses higher in the muscle, hepatopancreas, intestine, ovary and testis. The expression level of Es‐p38 gene at different stages of testis development shows no significant difference between the spermatocyte phase (July–August) and spermatid stage (August–October), but it rises significantly in the mid‐late period of sperm stage (December–January). This changing trend has a positive relationship with the E. Sinensis gonad development and reproduction stage, which preliminarily shows that Es‐p38 may function in the E. Sinensis testis development and the process of spermatogenesis. 相似文献
13.
The behavior of bigeye tuna (Thunnus obesus) in the northwestern Pacific Ocean was investigated using archival tag data for 28 fish [49–72 cm fork length (FL) at release, 3–503 days] released in Japanese waters around the Nansei Islands (24–29°N, 122–132°E) and east of central Honshu (Offshore central Honshu, 32–36°N, 142–148°E). Vertical behavior was classified into three types based on past studies: ‘characteristic’ (non‐associative), ‘associative’ (associated with floating objects) and ‘other’ (behavior not fitting into these two categories). The proportion of fish showing associative behavior decreased and that of characteristic behavior increased as fish grew, and this shift was pronounced at 60–70 cm FL. The fish usually stayed above the 20°C isotherm during the daytime and nighttime when showing associative behavior and below the 20°C isotherm during daytime for characteristic behavior. A higher proportion of characteristic behavior was seen between December and April around the Nansei Islands, and between September and December for offshore central Honshu. Seasonal changes in vertical position were also observed in conjunction with changes in water temperature. In this study, ‘other’ behavior was further classified into five types, of which ‘afternoon dive’ behavior, characterized by deep dives between around noon and evening, was the most frequent. The present study indicated that in the northwestern Pacific Ocean, the vertical behavior of bigeye tuna changes with size, as well as between seasons and regions. 相似文献
14.
15.
HEIDI DEWAR ERIC D. PRINCE MICHAEL K. MUSYL RICHARD W. BRILL CHUGEY SEPULVEDA JIANGANG LUO DAVID FOLEY ERIC S. ORBESEN DERKE SNODGRASS R. MICHAEL LAURS JOHN P. HOOLIHAN BARBARA A. BLOCK LIANNE M. MCNAUGHTON 《Fisheries Oceanography》2011,20(3):219-241
Swordfish are highly specialized top‐level predators that have been challenging to study. In this paper, data from 31 pop‐up satellite archival tags attached to swordfish from (i) the eastern Pacific, (ii) central Pacific, and (iii) western North Atlantic‐Caribbean were analyzed. Common across locations was a pronounced diel vertical pattern with daytime hours spent primarily below the thermocline and nighttime hours spent in warmer waters, close to the surface. One exception to this pattern was periodic daytime basking events which were most common in cooler waters off California. Maximum daytime depths were significantly correlated with light penetration as measured by the diffuse attenuation coefficient at 490 nm. Temperature did not appear to influence daytime depths, and swordfish tolerated both extremely low temperatures (4°C) and rapid and dramatic temperature changes (>20°C). Temperature did appear to influence the nighttime depths in the Pacific where fish typically remained in the surface mixed layer. In contrast, in the warm tropical Atlantic this was not the case, and nighttime depths were much deeper. In all areas, nighttime depth increased around the full moon. Given the parallels between the vertical movement patterns of swordfish and those of the deep sound scattering layer we suggest that swordfish vertical distribution patterns, especially during daytime, are influenced largely by resource availability. At night, when swordfish are typically targeted by fisheries, both ambient light and temperature influence movements. Understanding vertical movement patterns of swordfish can help evaluate gear vulnerability, improve population assessments, and potentially reduce fisheries bycatch. 相似文献
16.
Mingyue Chen Youxia Yue Juanyi He Peng Li Jie Yan Feifei Wang Fengna Cai Kaiya Zhou 《Aquaculture Research》2020,51(6):2322-2335
MicroRNAs (miRNAs) represent a class of endogenous small non‐coding RNAs with 18–25 nucleotides that are involved in diverse biological processes. In the present study, differentially expressed miRNAs in four different metamorphic stages of Eriocheir sinensis were comprehensively detected and validated from high‐throughput sequencing miRNA data sets. We identified and characterized 597 known miRNAs and 901 novel miRNAs from the four small RNA libraries. We also demonstrated the evolutionary conservation of miRNAs from Chinese mitten crab with those from other species. Analyses of miRNA expression profiles during brachyurization development of the Chinese mitten crab revealed that 86 mature miRNAs were dysregulated, 47 of which were significantly differentially expressed. The results of real‐time quantitative PCR analyses for a few selected miRNAs were similar to those of deep sequencing analyses. Intriguingly, the results of Gene Ontology annotation and KEGG pathway analyses indicated that miRNA gene clusters and families were consistently dysregulated at four different metamorphic stages, although they were enriched at various levels. Functional enrichment analysis revealed the versatile physiological roles (over six signal pathways) of these miRNAs. The results suggest that these miRNAs might play potential key roles in the regulation of gene expression in the brachyurization development of the Chinese mitten crab. Particularly, miR‐2a‐3p, miR‐305‐5p, miR‐263a‐5p and miR‐7‐5p may play major regulatory roles in the metamorphosis of E. sinensis. 相似文献
17.
Aeration rate adjustment at night to prevent sinking syndrome‐related death in the tiger grouper Epinephelus fuscoguttatus (Perciformes:Serranidae) larvae 下载免费PDF全文
下载免费PDF全文 Ching Fui Fui Akira Miura Yoshizumi Nakagawa Keitaro Kato Wataru Sakamoto Kenji Takii Shigeru Miyashita Shigeharu Senoo 《Aquaculture Research》2016,47(1):165-175
The effects of different aeration rates at night to prevent sinking syndrome‐related death (SSRD) of the tiger grouper, Epinephelus fuscoguttatus were examined. The aeration rates were fixed at 300 mL min?1 at daytime (07:00–19:00 hours) and regulated to 0, 300 and 900 mL min?1 at night (19:00–07:00 hours). Larval survival, growth, feeding intake, sinking velocity, distribution and behaviour, stress level, surface tension‐related death (STRD) and flow velocity distribution were assessed. The occurrence of SSRD in the tiger grouper was observed through the accelerated sinking velocity (Vl) (from 0.15 ± 0.09 cm s?1 at 4 days AH to 0.41 ± 0.09 cm s?1 at 12 days AH) coupled with larval passive swimming behaviour at night‐time. On the final day of experiment (15 days AH), larvae reared in 900 mL min?1 at night had attained significantly higher (P < 0.05) survival (34.4 ± 5.5%), growth (5.8 ± 0.5 mm) and feeding intake (60.46 ± 6.98 ind. larva?1). A favourable flow field for the tiger grouper was produced in 900 mL min?1 at night‐time, in which larvae were transported 15–25 cm above the tank bottom and 1.0 cm beneath the water surface. Under these night‐time rearing conditions, larval stress level and number of STRD reared in 900 mL min?1 compared with those observed in 300 mL min?1 remained insignificant, indicating that strong turbulence of flow velocity was not detrimental for larvae. Our findings recommend aeration at 900 mL min?1 at night as this could improve larval survival by reducing SSRD. 相似文献
18.
Life cycle closure for species inhabiting areas with daily varying currents but directed net water transport requires specific behavior to minimize losses due to advection of passive drifting life stages. Variations in swimming activity of different‐sized Crangon crangon (15–65 mm total length) were therefore monitored under constant laboratory conditions immediately after being caught in the German Wadden Sea. Activity of shrimps of different sizes, caught at different seasons, always peaked at times corresponding with ebb tide in the habitat from where they were taken. This behavior was maintained for several days if no external stimuli were present but shifted to night activity if a light–dark cycle was provided. The observed behavior/activity pattern was included in a coupled hydrodynamic and individual‐based model (IBM) and the shift in the location of a shrimp cohort was monitored over time. Performance of ebb tide activity not only allowed the shrimps to reach the preferred deeper winter and spawning areas but also allowed them to migrate against the dominating current from eastern nurseries to more western located spawning areas. Passively drifting larvae released at these locations and later larval and juvenile stages that perform flood tide transport can reach the nurseries again. This links the nurseries and adult spawning grounds and closes the migration triangle. 相似文献
19.
To determine the main expression site of major yolk protein (MYP) gene and the mechanisms for adaptation to starvation and refeeding in Strongylocentrotus intermedius, MYP mRNA expression amounts were analysed using a real‐time RT‐PCR. The results showed that MYP could be transcribed in the intestine, stomach, gonad and coelomocytes, and that the intestine was the main expression site of MYP gene in non‐starved urchins. The MYP synthesis in the intestine decreased during 15 days of starvation (67.70%, 52.58% and 71.35% of the control at 5, 10 and 15 days of fasting respectively) and then increased dramatically by different amounts (the peaks were 2.71‐, 12.16‐ and 7.89‐fold that of the control respectively) during the refeeding stages. Nevertheless, the expression amounts in the gonads did not decline, but increased continuously during all periods of fasting (2.66‐, 3.72‐ and 13.19‐fold that of the control at 5, 10 and 15 days of starvation respectively) and during the refeeding stages. At the end of the recovery feeding experiment, the levels reached 9.58‐, 17.48‐ and 100.69‐fold that of the control. These data suggested that the ‘priority’ strategy for the sea urchin is to reduce MYP expression amounts in the intestine if food is limited and to increase MYP gene expression in the gonad to protect reproductive function. 相似文献
20.
斜带石斑鱼仔鱼的摄食节律及日摄食量 总被引：18，自引：1，他引：18
鱼类的日摄食节律分为白天摄食、晚上摄食、晨昏摄食和无明显节律四种类型。为了解斜带石斑鱼早期发育阶段的日摄食量及昼夜摄食规律,对孵化15天的仔鱼(全长4.86±0.38mm)在不同昼夜节律下的日摄食量和摄食节律进行了研究。结果如下:实验包括自然昼夜组(对照组)、持续光照组和持续黑暗组,各组对轮虫的日摄食量分别为142个/尾、156个/尾和47个/尾;白天摄食量比例分别为总摄食量的91.3%,80.5%和71.7%。对照组在正午(14:00)出现一个明显的摄食高峰;持续光照组在下午(16:00～18:00)出现明显的摄食小高峰;黑暗组则未出现明显的摄食峰。持续光照组在夜间的群摄食率明显高于对照组;黑暗组在白天的群摄食率明显低于对照组。持续光照组摄食强度小幅度增加,日摄食量为对照组的109.9%;而黑暗组摄食强度则明显下降,日摄食量为对照组的33.1%。综上所述,斜带石斑仔鱼摄食节律明显,属于典型的白天摄食类型;仔鱼的摄食与光照有着紧密的关系。 相似文献