Water depth and feed pellet type effects on growth and feed utilization in the rearing of green turtle (<i>Chelonia mydas</i>Linnaeus, 1758)

Kaewtapee³

et al. 2021

Aquaculture Research

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Bigfin reef squid (Sepioteuthis lessoniana) has been successively cultured through multiple generations, but little is known about the factors affecting feeding regimens. In the current study, optimal feeding frequency of five‐week‐old bigfin reef squids was investigated in laboratory conditions. The squids (1.48 ± 0.03 g initial weight) were assigned to four feeding frequencies: two (2TD), three (3TD), four (4TD) or five (5TD) times daily, and they were fed with post‐larval stage of Pacific white shrimp (Litopenaeus vannamei) over the three weeks of experiment. At the end of the feeding trial, the squids receiving 4TD and 5TD had the highest growth and feed utilization, and the least size variation among the treatment groups. Significant decrease in chymotrypsin‐specific activity was observed in squids receiving 5TD relative to 2TD (p < 0.05), while a moderate level was observed across the remaining treatments. This matched the available and unavailable nutrients present in faeces, assessed from thermal responses. Mantle quality, in terms of RNA concentration, was the highest in squids fed 4TD or 5TD, while protein concentration and RNA/protein ratio did not differ across the four feeding frequencies tested. Also, the most crude lipid was observed in squids fed 5TD, followed by 4TD that were superior to 2TD or 3TD treatments, while crude protein and ash did not differ. These findings indicate that feeding four or five times daily is most appropriate. This practical feeding protocol can be used for mariculture of this species.

Section: Discussionsupporting

confidence: 90%

Optimal feeding frequency for bigfin reef squid (Sepioteuthis lessoniana)

Satjarak

Kaewtapee³

et al. 2021

Aquaculture Research

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“…The values of FCR from 0.80 to 1.02 are relatively low, which is a good trait. Similar range of FCR has been reported in green turtle [ 39 ] and in northern river terrapin [ 40 ], having respective ranges from 0.61 to 0.81, and from 1.03 to 1.46. Here the estimation of consumed pellet feed was based on dry matter, while the weight gain of turtles includes a large fraction of water in the tissues because it is on wet weight basis.…”

Section: Discussionsupporting

confidence: 80%

“…Feed utilization can be assessed through the activity of digestive enzymes. In endangered species, the digestive enzymes from feces can trace physiological response due to varying dietary treatments [ 9 , 18 , 39 ]. A similar pattern of trypsin from feces and digestive tract has been reported in crustacean [ 16 ] while the comparison between enzyme sources in reptiles has not been performed.…”

Section: Discussionmentioning

confidence: 99%

Optimal Feeding Frequency for Captive Hawksbill Sea Turtle (Eretmochelys imbricata)

Jualaong¹,

Kanghae

et al. 2021

Animals

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Hawksbill sea turtle (Eretmochelys imbricata) has been reared in head-starting captivity programs, while the feeding regimens have never been optimized. In the current study, the feeding frequency of hawksbill sea turtle was investigated in indoor experimental conditions. Two-month-old turtles (38.98 ± 0.02 g) were distributed to triplicates of five treatments containing three turtles each and they were fed at different frequencies: one meal daily at 12.00 h (1M12), two meals daily at 08.00 and 12.00 h (2M8–12), two meals daily at 08.00 and 16.00 h (2M8–16), two meals daily at 12.00 and 16.00 h (2M12–16), or three meals daily at 08.00, 12.00 and 16.00 h (3M8–12–16). At the end of an 8-week trial, growth performance (specific growth rate 2.39 ± 0.02% body weight day−1) and feed consumption (feeding rate 2.00 ± 0.43 g day−1) were highest for turtles fed 2M8–16, followed by 2M12–16 or 3M8–12–16 relative to the other treatments (p ˂ 0.05). These treatments had significantly higher trypsin specific activity and trypsin/chymotrypsin ratio, and vice versa for lipase specific activity and amylase/trypsin ratio, relative to the remaining treatments. These match well with the fecal thermal properties that indicate amounts of available and unavailable nutrients present in the feces. Hematological parameters and carapace elemental composition showed no negative effects to turtles in 2M8–16 treatment. Therefore, two meals daily with long time interval were optimal for feeding hawksbill sea turtle. Findings from the current study could be directly used as a feeding guideline supporting the head-starting programs of this species.

“…However, this kind of comparative study can be performed with other non-endangered model turtle species, such as soft-shelled turtles (Pelodiscus sinensis), to collect more evidence prior to application in endangered species. Recently, the specific activities of gastric and pancreatic enzymes in fecal samples have been used as indicators for monitoring feed utilization in green turtles [18][19][20]26,33]. In the current study, the effects of background color on the specific activities of these digestive enzymes were clearly observed.…”

Section: Discussionmentioning

confidence: 52%

Optimal Background Color for Head-Starting Northern River Terrapins (Batagur baska Gray, 1831)

Jualaong¹,

Ninwat³

et al. 2020

Animals

Self Cite

Background color has significant effects on the lifestyles of various animal species. In this study, the effects of wall background color on growth, feed utilization, specific activity of gastric and pancreatic enzymes in fecal samples, fecal thermal properties, carapace elemental profile, and hematological parameters were investigated in northern river terrapin (Batagur baska Gray, 1831) in order to optimize the head-starting conditions. The terrapins (70.13 ± 0.04 g initial weight) were completely randomized into five types of colored tanks (transparent, green, red, blue, and black) and reared for twelve weeks. At the end of the experiment, tank color had no effect on survival and growth performance, but had significant effects on feeding rate, feed conversion ratio, and protein efficiency ratio (p < 0.05). Terrapins reared with black, red, or blue backgrounds had the highest feed utilization among the treatments. Among these three groups, analysis of specific activity of gastric and pancreatic enzymes in fecal samples and fecal thermal properties suggested improved digestive functionality in terrapins reared with a blue background relative to the other treatments. Carapace elemental composition and hematological parameters indicated no negative effects on health status of the terrapins reared with this optimal treatment. Findings from the current study support the head-starting program of northern river terrapins before release to natural habitats, and could also be applied in aquaria or zoos for public display.