不同饥饿时间对白斑狗鱼恢复投喂期间生长性能的影响

在水温22~26℃条件下,研究了在不同饥饿时间处理后再投喂对白斑狗鱼(Esox lucius)生长性能的影响,试验设置饥饿14、21、28、35、42 d组和正常投喂对照组,各组饥饿结束后恢复正常投饵,在投喂后以7 d为一个生长阶段,比较各处理组的增重率、特定生长率、摄食率、饲料系数,试验周期为56 d。结果显示,随着饥饿时间的延长,白斑狗鱼的总体重损失率呈逐渐升高的趋势,而各饥饿阶段体重损失率呈下降的趋势;各饥饿处理组恢复投喂后的增重率和特定生长率均显著高于对照组(P<0.05),且随饥饿时间的延长而逐渐升高,但在恢复投喂后的第35天,S14组(饥饿14 d组)与对照组无显著性差异(P>0.05);各饥饿处理组恢复投喂后的摄食率随饥饿时间的延长而显著性升高(P<0.05);饵料系数随饥饿时间的延长而逐渐下降,其中在第14天时,S42组(饥饿42 d组)的饵料系数显著高于其他饥饿处理组(P<0.05),与对照组无显著性差异(P>0.05)。在同一饥饿处理组,随着投喂时间的延长,增重率、特定生长率和摄食率均呈显著性下降的趋势(P<0.05),饵料系数呈升高的趋势,其中S14组在第35天时恢复到对照组水平。结果表明:摄食率升高和饵料系数下降是饥饿再投喂白斑狗鱼增重率显著上升的原因,且这种生长倾向随着恢复投喂时间的延长而不断减弱。     

饥饿和再投喂对日本黄姑鱼代谢率和消化器官组织学的影响

采用封闭式呼吸仪测定日本黄姑鱼(8.14±1.07 g)在饥饿和恢复投喂过程中的耗氧率;用石蜡切片法观察和分析饥饿和再投喂对日本黄姑鱼消化器官形态结构和组织学的影响。结果表明:随着饥饿时间的延长,其耗氧率逐渐降低;恢复投喂之后,其耗氧率开始逐步上升。从组织结构看,食道无明显变化,而胃、肠和肝胰脏则随着饥饿时间的延长出现不同程度的损伤;饥饿5 d组无明显变化,而饥饿15 d组变化明显,表现为胃腺细胞收缩,皱壁和上皮细胞高度减少,分泌颗粒减少,肠胃绒毛退化,肝组织致密,肝细胞内脂滴减少,胰腺泡缩小,排列不规则;饥饿10 d组介于饥饿5 d组和饥饿15 d组之间,再投喂各主要结构均有恢复。     

饥饿后再投喂对星斑川鲽生长、摄食的影响

采用饥饿不同时间后再恢复投喂相同时间的方法,在温度(19±1)℃、盐度32±1的条件下,对相同规格的星斑川鲽[(26.02±0.30)g]的生长、摄食进行了研究。研究结果表明,饥饿5 d的星斑川鲽在恢复投喂20 d后鱼体质量超过对照组水平,差异不显著(P>0.05),获得了超补偿生长;饥饿10d的星斑川鲽恢复投喂20 d后,鱼体质量接近对照组水平,差异不显著(P>0.05),获得了完全补偿生长;饥饿15 d的星斑川鲽恢复投喂20 d后,鱼体质量未能达到对照组水平,差异显著(P<0.05),获得了部分补偿生长。饥饿后再投喂处理对星斑川鲽的体质量、全长、特定生长率、比肝质量等生长指标均有显著影响;对总摄食量、平均摄食量、食物转化率、摄食率、吸收率、排粪率的影响亦比较明显。结果表明,饥饿5 d的星斑川鲽在恢复投喂后生长最快,表现出很强的补偿生长能力。     

Compensatory growth and body composition of juvenile black rockfish <Emphasis Type="Italic">Sebastes schlegeli</Emphasis> following feed deprivation

ABSTRACT:   Compensatory growth, feeding rate, feed efficiency and chemical composition of juvenile black rockfish (mean weight 1.43 g) were investigated for 35 days after a 14-day feed deprivation treatment under four feeding conditions: one group continuously fed (control) and the other three groups fasted for 5 days (F5), 10 days (F10) and 14 days (F14). All fasted fish were re-fed from day 15. Only F5 achieved the same body weight as the control, indicating that complete compensation occurred in F5. The specific growth rate (SGR) of F5 was the highest at day 21 and then decreased thereafter, showing higher values than the control at days 21, 28 and 42. In contrast, although SGRs of F10 and F14 were higher than that of the control during the whole refeeding period except day 21, they did not catch up the control in body mass, indicating that only partial compensation occurred in F10 and F14. The feeding rate (FR) of all groups except F14 changed in a pattern similar to SGR (Spearman's rank correlation, r _s > 0.9), suggesting that SGR varied depending on FR. Similar feeding efficiencies (FEs) were found in the four groups and they did not vary significantly during the whole refeeding period, suggesting that FE was not the factor affecting SGR. At day 14, the ratios of lipid to lean body mass in F10 and F14 were lower than those in the control and F5, and there was no difference between the control and F5. At day 49, however, only F14 showed a lower value than the other three groups, and there was no difference among the three groups. These results indicate that juvenile black rockfish fasted for 5–14 days can exhibit compensatory growth after refeeding, but timing and degree vary depending on the duration of feed deprivation.     

饥饿和再投喂对中间球海胆性腺发育的影响

对中间球海胆Strongylocentrotus intermedius进行了不同时间的饥饿和再投喂试验。采用各组“饥饿时间 投喂时间”相同的试验设计,在30 d内,试验组(S3、S6、S9、S12组)海胆分别饥饿3、6、9和12d后再连续饱食投喂直至试验结束,同时设对照组S0。结果表明:试验结束时S3组海胆性腺重、性腺指数均接近对照组,其余各组较对照组低;特殊生长率在再投喂的第2 d或第4 d出现最大值。性腺组织学观察的结果表明:对照组海胆性腺为滤泡型,由生殖细胞和营养细胞构成,发育至生长期;随着饥饿时间的延长,雄海胆性腺中成熟精子的数量减少,雌海胆性腺中初级卵母细胞发育迟缓,而雌、雄海胆性腺中营养细胞的数量无明显变化;再投喂后,性腺有不同程度的发育。     

饥饿及再投喂对日本囊对虾蛋白质代谢的影响

研究了体重为(13.08±2.40)g、体长为(10.37±0.73)cm的日本囊对虾Marsupenaeus ja-ponicus在饥饿和再投喂状态下蛋白质代谢的变化。对照组C连续饱食投喂10 d,试验组S10、S15、S25分别饥饿10、15、25 d后再恢复饱食投喂10 d。结果表明:在饥饿状态下,日本囊对虾肌肉中蛋白质的含量在饥饿前15 d迅速上升,饥饿第15~25 d趋于平稳,肝胰脏中蛋白质的含量则一直较稳定;恢复投喂后,肌肉中蛋白质的含量下降,而肝胰脏中蛋白质的含量上升。血浆中蛋白质的含量在饥饿前期(0~5 d)保持平稳,但在之后的第5~15 d则迅速下降,最后又恢复至最初水平;恢复投喂后,除S25组外其余各组血浆中蛋白质的含量都呈上升趋势,且试验组显著高于对照组(P<0.05)。肌肉中RNA/DNA的值在饥饿初期(0~5 d)略有下降,之后保持稳定,肝胰脏中RNA/DNA的值则在短期下降后有所上升;恢复投喂后,肌肉中RNA/DNA的值除S25组外其余各组均呈上升趋势,而肝胰脏中RNA/DNA的值除C组外其余各组均显著上升(P<0.05)。     

饥饿和再投喂对西伯利亚鲟生化组成的影响

试验设饥饿0、3、6、9、12 d(记为S0(对照)、S3、S6、S9、S12组),然后各恢复投喂20 d,分析了饥饿和再投喂对西伯利亚鲟Acipenser baeri生化组成的影响。结果表明:饥饿结束时,S6和S9组蛋白质含量略高于S0组,S3、S12组略低于S0组,但差异均不显著;除S3组外,各饥饿组脂肪含量均低于对照组,且S6组有显著差异(P<0.05);各组鱼体水分含量有所上升,其中S12组与S0组差异显著(P<0.05)。恢复投喂后,S3、S12组蛋白质含量低于S0组,S6、S9组蛋白质含量高于S0组,但差异均不显著;各组鱼的脂肪含量均升高,但各饥饿组的脂肪含量均低于对照组,且S9组达到显著水平(P<0.05);各组水分含量下降,其中S12组变化显著(P<0.05)。     

饥饿和再投喂对美国红鱼消化器官组织学的影响

用石蜡切片方法观察和分析饥饿和再投喂对美国红鱼(Sciaenopsocellatus)消化器官形态结构和组织学的影响。鱼样体重(8.25±0.5)g,体长(8.84±0.27)cm。从形态结构看,饥饿与再投喂前后食道无明显变化,而饥饿10、15d的实验鱼胃壁变薄,幽门盲囊变小,肠管收缩,呈透明状,肝胰腺萎缩,呈姜黄色,胆管呈深绿色。从组织结构看,食道无明显变化;饥饿时间不同,各组织受损害和恢复程度不同。饥饿5d的实验鱼基本同对照组;而饥饿10、15d的实验鱼组织变化较明显:皱襞和上皮细胞高度均减少,分泌颗粒减少。胃腺细胞收缩,结构不完整;幽门盲囊长度和直径变小;肠直径变小,微绒毛退化;肝组织致密,肝细胞内脂滴减少,体积缩小;胰腺泡缩小,排列不规则。再投喂各主要结构均有所恢复,有些恢复到饥饿前水平,但大部分未能达到。     

限食以及再充分投喂对鲻鱼血液生化指标的影响

2001年12月—2002年3月,水温为19~24℃,对鲻鱼[初始体重:(204.42±23.13)g]进行了不同时间的限食处理后再充分投喂的恢复生长试验。试验设定2种投喂方式,对照组(饱食组)在试验期间正常投喂;限食组(半饱组)在限食期投喂量为饱食组的1/2,重喂期则恢复投喂。试验期为8周。分别在限食期的第0、1、2、4周和重喂期第1、2、4周取样,每次6条鱼。试验结果表明:限食状态下,鲻鱼半饱组血糖、血脂和血浆蛋白含量均显著降低;再充分投喂后,各血液生化指标均恢复到对照组水平。鲻鱼限食4周后,在4个星期的恢复生长过程中产生了显著的补偿效应。     

Anabolism,catabolism and proteomic analysis in the slow‐twitch muscle of pacu (Piaractus mesopotamicus) submitted to prolonged fasting followed by refeeding

Here, we aimed to study the slow muscle of the fish Piaractus mesopotamicus submitted to 30 days of fasting (D30) followed by 1 day (D31) or 30 days of refeeding (D60). Histological analysis of fibre diameter was performed in D30 and D60. The gene expression of parvalbumin (pvalb), atrogenes (murf1a, murf1b, mafbx) and anabolic genes (igf‐1, mtor) was analysed using RT‐qPCR in D30, D31 and D60. The proteome was obtained by shotgun proteomics at D30 and D60, and the set of differentially expressed proteins was analysed by bioinformatics. In all experiments, the control was regularly fed fish. The histological analysis showed no changes in muscle fibre diameter. The expression of catabolic and anabolic genes was not changed, except for the downregulation of igf‐1 in D30 and of mafbx in D31. The expression of pvalb was not changed in D30 and D60 but was decreased in D31. The proteomic analysis identified 169 proteins in D30 (24 upregulated and 18 downregulated) and 170 proteins in D60 (17 upregulated and 21 downregulated); many of them were related to energetic metabolism and intracellular Ca²⁺ homoeostasis. Overall, our results indicate that the slow‐twitch muscle presented few changes upon prolonged fasting and refeeding condition.