Efficacy and tolerance of lutein as colourant in diet of juvenile soft-shelled turtlePelodiscus sinensis

Abstract

The effects of dietary supplementation of lutein on the growth, haematological profile and pigmentation in target tissues of the soft-shelled turtles were investigated. Five experimental diets were prepared with lutein levels at 1.16 (D1, control), 70.3 (D2), 132 (D3) and 239 (D4) mg kg À1 , and one more high inclusion level of 3410 mg kg À1 (D5) was included for tolerance test. Each diet was fed to 24 juvenile turtles for 8w. Specific growth rate (SGR) in D2, D3 and D4 was significantly higher than that of group D1 and D5. Skin yellowness (b*) and chroma (C*) of both carapace and plastron skin were all significantly increased with higher dietary lutein levels. Dietary lutein supplementation turned the H°values of skins into yellowness. The accumulation of lutein in skin and muscle also augmented significantly with increasing lutein levels and fit a logarithmic correlation with dietary lutein levels. There were almost no differences in haematological parameters of all turtles. Lutein is an efficient and safe colourant in diet of soft-shelled turtle. The optimal inclusion levels for the highest SGR and desired skin colour in carapace and plastron of soft-shelled turtle were 162, 142 and 143 mg kg À1 , respectively.

Effects of Dietary Xanthophyll Supplementation on Growth Performance, Body Color, Carotenoids, and Blood Chemistry Indices of Chinese Soft‐Shelled Turtle Pelodiscus sinensis

“…In the current study, the addition of 120 mg/kg xanthophyll significantly increased the yellowness in both the carapace and plastron, whereas it decreased the redness in the plastron. There were some differences between the conclusion regarding the optimal xanthophyll additions from this study and that of Liu et al (2013), which concluded that the optimal dietary lutein levels for the desired yellowness of skin color in the carapace and plastron of juvenile Chinese soft‐shelled turtles were 142 mg/kg and 143 mg/kg, respectively. This may be because the experimental turtles for the studies were at different growth stages and in different geographical groups.…”

“…Niu et al (2009) declared that factors such as species, the developmental stage, the source of the pigments, the addition level of the pigments in feed, and the duration of feeding should be taken into consideration to understand the different effects of carotenoids on growth performance. In a study by Liu et al (2013), the results showed that lutein (70.3-239 mg/kg) significantly improved SGR in the Chinese soft-shelled turtles (4.81 AE 0.04 g). Another study showed that the optimal β-carotene level…”

“…Soft‐shelled turtles with yellow‐like color have been associated with higher quality, healthier meat, and higher commercial value in the market. Liu et al (2013) reported that lutein (extracted from marigold) was a safe and efficient colorant when it is added to the diet of Chinese soft‐shelled turtles, and it could improve the yellowness and chroma of the skin. However, little other research has been reported on the effects of pigments on the body color of Chinese soft‐shelled turtles.…”

Effect of dietary canthaxanthin and xanthophyll on growth, antioxidant capacity, body colour, and BCO2 , CAT and SOD2 gene expression in Chinese soft‐shelled turtle ( Pelodiscus sinensis )

“…In juvenile yellow catfish, carotenoids improve their growth performance and feed efficiency (Wang, 2012). Studies also showed that adding lutein (70.3-239 mg/ kg) can promote SGR of Chinese soft-shelled turtles (4.81 ± 0.04 g) (Liu et al, 2013), and the optimal β-carotene level for turtle growth (mean weight: 5.7 g) was 49.1 mg/kg (Chen & Huang, 2011). Our previous research suggested that 80-120 mg/kg xanthophyll and 8% spirulina in the diet have an effective influence on the growth performance of turtles (He et al, 2019;Wang et al, 2020).…”

“…Studies have shown that adding carotenoids such as xanthophyll (Liu et al, 2013;Wang et al, 2020), corn gluten meal (Zhang, 2013) and spirulina (Ning et al, 2000) to feed can improve the body colour of soft-shelled turtle. Nevertheless, the effect of red carotenoids in turtle has not been studied so for.…”