Comparative Study of the Feeding Characteristics and Digestion Physiology of Haliotis discus hannai and Haliotis gigantea

Abstract

Abalone (Haliotis spp.) are typical nocturnal creatures but Haliotis discus hannai is bold and active in the nighttime whereas H. gigantea tends to be timid and inactive. In this study, we quantified and compared differences in movement, feeding, and digestive physiology between H. discus hannai and H. gigantea as well as the potential molecular mechanisms on the basis of video observations and expression levels of genes related to feeding regulation. The feeding behaviors of both species were characterized by significant circadian rhythms (P < 0.05). However, the distance moved and the cumulative duration of movement were 2.61 and 1.94 times higher, respectively, in H. discus hannai than in H. gigantea over the 24-h cycle. The cumulative duration of feeding by H. discus hannai was only 1.15 times that by H. gigantea, but the feeding time as a percentage of the cumulative duration of movement (FTP) was up to 94.6% for H. gigantea and only 56.0% for H. discus hannai. The peaks for α-amylase activity and NPF expression levels in both species as well as the peak OX2R expression level in H. gigantea occurred during 20:00–00:00 h. By contrast, the peaks for alginate lyase activity and NPYR expression levels in H. discus hannai occurred at 16:00 h, when the FTP was significantly higher for H. discus hannai than for H. gigantea. These initial findings quantify specific behavior parameters and thus provide a reference for the selection of appropriate feeding strategies and the proliferation of abalone via bottom sowing.

Role of Bmal1 in mediating the cholinergic system to regulate the behavioral rhythm of nocturnal marine molluscs

“…The results of the cosine analysis suggested that the melatonin content and expression levels of AANAT and ASMT in the 12L:12D and 24L:00 groups exhibited a significant cosine diurnal rhythm and tended to be “higher during the day and lower during the night”, suggesting that abalones maintain their diurnal rhythm regardless of changes in the light cycle. Even though H. gigantea tends to be more shy and less active than H. discus hannai , the feeding behaviors of the two species show significant diurnal rhythms, with feeding peaks at ZT12 (00:00) [46] , further demonstrating that light is one of the external environmental factors most likely to impact the timing of biological rhythms. In the course of the experiment, food was provided at 17:00 pm every day.…”

Transitions, challenges and trends in China's abalone culture industry

“…discus hannai and ‘shy’ H . gigantea were significantly different 92 . With both feeding peaks appearing at 00:00, H .…”

“…91 Lyu et al found that the movement and feeding behaviours of 'lively' H. discus hannai and 'shy' H. gigantea were significantly different. 92 With both feeding peaks appearing at 00:00, H. gigantea would spend 94.6% of movement time feeding, while the feeding time of H. discus hannai only accounted for 56.0% of its cumulative movement duration. The maximum value of the alginate lyase activity of H. discus hannai and that of the expression levels of the feeding-related receptor (NPYR) appeared at 16:00.…”

Feeding strategy trade-off and selection of marine nocturnal gastropods under predation risk

“…Increasing the success of stock enhancement requires assessments of how well the hatchery-bred individuals adapt to wild conditions. In particular, abalones are a group of typical nocturnal animals that stay away from light and hide in dark areas in the daytime, with a feeding peak at the night (Lyu et al, 2021). Olfaction cues are widely used by aquatic gastropods to detect and avoid predators, as well as to search for food (Manriquez et al, 2021).…”