亚麻酸对卵形鲳鲹幼鱼生长性能、消化酶活性及抗氧化能力的影响

为制定卵形鲳鲹(Trachinotus ovatus)投喂策略，文章研究了卵形鲳鲹昼夜摄食、耗氧规律和胃肠排空时间。摄食节律采用分段式连续投喂法(1昼夜，每隔2 h投料1次，连续3 d)；耗氧节律采用流水呼吸法测定(1昼夜，24 h中每2 h测定1次)；胃肠排空时间实验采用一次饱食投喂法(1昼夜，每隔2 h取样1次)。结果表明，卵形鲳鲹属于白天摄食类型，分别在10:00和14:00—16:00间出现2个摄食高峰(P<0.05)；耗氧高峰期分别在08:00和16:00出现(P<0.05)；饱食后，胃内含物比率下降迅速(P<0.05)，7 h下降约50%，第15小时出现极低值(P<0.05)，19 h后胃内含物为0。在摄食后3 h内全肠内含物比率迅速升高，第11小时达到最大值(P<0.05)，之后逐渐降低，在第21小时出现极低值(P<0.05)。研究建议在卵形鲳鲹网箱养殖生产中，宜在光线较强、耗氧和摄食高峰的上午(09:00—10:00)和下午(14:00—16:00)时段进行投喂，投喂频率2~3次·d⁻¹，投喂间隔7~9 h。

Circadian rhythms and feeding time in fishes

In order to determine a scientific feeding strategy for Trachinotus ovatus, we investigated the day and night diet feeding, oxygen consumption rhythm and gastrointestinal evacuation time of the fish in laboratory. The diet feeding rhythm was invstigated by a continuous feeding with fixed interval (feeding once every two hours day and night for three continuous days). The oxygen consumption rhythm was measured by flow-water breathing method (measuring once every two hours day and night for 24 h). The gastrointestinal evacuation time was measured by a full feeding method (sampling once every two hours day and night for a day). Results show that T. ovatus had a daytime feeding pattern with two extremely obvious feeding peaks (10:00 and 14:00−16:00, P<0.05), and the peak periods of oxygen consumption appeared at 08:00 and 16:00, respectively (P<0.05). The stomach digesta ratio of T. ovatus decreased sharply after feeding (P<0.05), nearly 50% at 7^th hour, and reached to zero after 19 h. However, the bowel digesta ratio of T. ovatus increased sharply after 1−3 hours of feeding, and reached the maximum at 11^th hour and the minimum at 21^st hour. Thus, it is suggested that the optimal feeding periods of T. ovatus are 09:00−10:00 and 14:00−16:00 with strong light, oxygen consumption and peak feeding. The feeding frequency is 2−3 times per day and the feeding interval is 7−9 h.