斑点叉尾和杂交鲟幼鱼昼夜摄食节律和胃肠排空时间的研究

摘要

A once-per-day satiation feeding (one day was divided into eight time periods, each time period was used as one treatment, the fish of each treatment was fed to apparent satiation once a day) and a continuous feeding with fixed interval (one day was divided into eight time periods, the fish of each tank was fed to apparent satiation, eight times a day) were used to investigate the diet feeding rhythm of channel catfish and hybrid sturgeon, and gastrointestinal evacuation times of the tested fish after feeding during a 24h collection period were also studied. The results showed that channel catfish exhibit a 24h diet feeding cycle and the two feeding peaks appeared at the 06:00 and 18:00 time periods, respectively under two feeding scenarios (P<0.05). Hybrid sturgeon displayed a 24h diet feeding cycle and the three feeding peaks appeared at the 11:00, 17:00, and 05:00 time periods, respectively under a once-per-day satiation feeding. However, hybrid sturgeon displayed a 48h diet feeding cycle and the three feeding peaks appeared at the 11:00, 17:00 and 36:00 time periods, respectively under a continuous feeding with fixed interval. Stomach digesta ratio of channel catfish decreased sharply after a 1-9h feeding (P<0.05), and it reached a minimum after the 24h feeding. But the bowel digesta ratio of the channel catfish increased sharply after a 1-9h feeding, and it achieved the maximum value after the 9h feeding and it achieved the minimum value after the 24h feeding. Stomach digesta ratio of hybrid sturgeon decreased sharply after a 1-7h feeding (P<0.05), and it reached a minimum after the 24h feeding, but the bowel digesta ratio of the fish increased sharply after a 1-7h feeding and it reached the minimum value after the 24h feeding. Our results indicated that channel catfish and hybrid sturgeon exhibited the different diet feeding rhythms under two feeding scenarios, and their diet feeding rtythms were not only affected by their gastrointestinal evacuation time, but also by the different feeding time. The present results suggested that the optimal feeding period were dawn (05:00-06:00) and dusk (17:00-18:00) in cultured of juvenile channel catfish and hybrid sturgeon.%采用一次饱食投喂(将一昼夜分为8个时间段,每个时间段作为一个处理组,每天每个处理组饱食投喂一次)和分段式连续投喂(将一昼夜分为8个时间段,每天每个实验缸连续投喂8次)两种方法研究斑点叉尾和杂交鲟幼鱼的昼夜摄食节律,同时研究它们在摄食后24h内胃和全肠的排空时间。结果显示,在两种投喂方式下,斑点叉尾均表现出24h 一周期的摄食节律,两个日摄食率高峰值均出现在06：00和18：00(P<0.05)。杂交鲟在一次饱食投喂下表现出24h一周期的摄食节律,高峰值分别出现在11：00、17：00和05：00,在分段式连续投喂时表现出48h 一周期的摄食节律,高峰值分别出现在11：00、17：00和36：00。在摄食后1-9h 内,斑点叉尾的胃内含物比率急剧降低(P<0.05),并在24h 时出现极低值(P<0.05),而1-9h 内全肠内含物比率迅速升高(P<0.05),在9h时达到最大(P<0.05),在24h出现极低值(P<0.05)。在摄食后1-7h内,杂交鲟的胃内含物比率迅速下降(P<0.05),在24h 时出现极低值(P<0.05),1-7h 内肠内含物比率迅速升高(P<0.05),24h 时呈现极低值(P<0.05)。结果表明,两种实验鱼表现出不同的昼夜摄食节律,该节律受各自胃肠排空时间的影响,也受投喂时间的影响。研究建议,在斑点叉尾和杂交鲟幼鱼的养殖中宜在光线较弱的清晨(05：00-06：00)和黄昏(17：00-18：00)进行投喂。