Effects of sandy substrate and light on hypermelanosis of the blind side in cultured Japanese flounder Paralichthys olivaceus

Iwata, Nobuhisa; Kikuchi, Kotaro

doi:10.1007/978-94-015-9016-7_23

Cited by 30 publications

(43 citation statements)

References 8 publications

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“…The ability to vary pigment patterns in response to their environment is not uncommon, and the particular ability of flatfish to adjust their ocular side to match the substratum is widely described (Burton & O'Driscoll 1992, Iwata & Kikuchi 1998, Healey 1999, Bolker et al 2005. However, this represents physiological colour changes based on local aggregations of melanosomes unmasking the dense clusters of iridophores, thus making them visible, versus melanosome dispersion within melanophores inducing a general darkening of the skin, which is likely what we observed during the winter and summer months of the passive observation study.…”

Section: Discussionmentioning

confidence: 99%

Hyperpigmentation in North Sea dab Limanda limanda. II. Macroscopic and microscopic characteristics and pathogen screening

Noguera¹,

Feist²,

Bateman³

et al. 2013

Dis. Aquat. Org.

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An increasing trend in the prevalence of hyperpigmentation in the common dab Limanda limanda from the North Sea prompted us to investigate the potential role of infectious agents as causes or contributing factors to the condition. Dab representing 3 severity grades of hyperpigmentation were sampled for virology, bacteriology, histopathology and ultrastructure assessments. No cytopathic effect was recorded during virology testing, and bacteriological results showed no differences between normal and hyperpigmented dab. Histopathological assessment showed that the most significant changes occurred in the dermis as a result of chromatophore hyperplasia, namely melanophores and iridophores, alongside loose melanin granules. Dermal lymphocytic infiltration occasionally expanding into the epidermis and the underlying musculature was more frequent in highly pigmented dab than in normal fish, suggesting an active immune response. Ultrastructure studies showed additional disruption of the epithelial layer, with loose melanin granules between cells and a number of single or aggregated melanocytes. Dab representing different grades of hyperpigmentation kept in the laboratory alongside normal fish for a monitoring period of 18 mo showed no changes in their pigment distribution pattern, nor occurrence of new pigment in the normal fish. The current investigation found no association of hyperpigmentation in the common dab with infectious agents; therefore, understanding the cause of the condition remains a challenge which can now more reliably focus on a non-infectious origin hypothesis.

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Section: Discussionmentioning

confidence: 99%

Hyperpigmentation in North Sea dab Limanda limanda. II. Macroscopic and microscopic characteristics and pathogen screening

Noguera¹,

Feist²,

Bateman³

et al. 2013

Dis. Aquat. Org.

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“…The ability of flatfishes to adjust their upper-side colouration to match the substratum is well known (Burton & O'Driscoll, 1992;Ramachandran et al, 1996;Iwata & Kikuchi, 1998;Healey, 1999). This capacity is based on neurotransmitter-mediated changes in the melanophores.…”

Section: Developmental Timingmentioning

confidence: 99%

Pigmentation development in hatchery‐reared flatfishes

Bolker

Hill

2000

Journal of Fish Biology

133

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Malpigmentation is common in hatchery-reared flatfishes, decreasing the market value of whole fish, and increasing the risk of predation for juveniles released to enhance wild stocks. Pigmentation development in flatfishes occurs in two phases. First, during embryonic and larval stages pigment cells differentiate on both sides of the body. Second, at metamorphosis larval melanophores disappear, and adult melanophores differentiate on the ocular but not on the blind side. Malpigmentation seems to result from disruptions of the second phase, and may take the form of albinism on the ocular side or darkening of the blind side. Both types of aberration may be related to aspects of the hatchery environment such as lighting, substratum, and diet. Larval nutrition appears to be a key factor and enrichment of larval diets with fatty acids and Vitamin A can greatly reduce malpigmentation rates; however, levels sufficient to prevent pigmentation defects frequently cause other abnormalities. Two developmental explanations for albinism have been proposed. The first is that differentiation of ocular-side skin follows the normal blind-side pathway and adult melanophores therefore fail to develop on the ocular side. The second hypothesis suggests that dietary deficiencies inhibit retinal development and the resulting visual defects lead to failure of a hormonal signal required for melanophore differentiation. These hypotheses may well be complementary; as yet neither has been thoroughly tested. Definitive tests will require a combination of manipulative techniques such as tissue transplantation and cell culture with nutritional, behavioural and hormonal assays. Such integrative studies will further the understanding both of normal pigmentation development and of the environmental factors that contribute to high rates of albinism in hatchery-reared flatfish. 2000 The Fisheries Society of the British Isles

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“…In addition, a sand substrate was introduced into the tanks as an additional measure to prevent the staining [6][7][8][9][10] and to minimize the occurrence of injury-induced darkening on the blind side (H. Echigo and M. Tagawa, unpublished data, 2013). Therefore, it is probable that the occurrence of new black scales in the white area of the blind side is attributed to the transplantation and removal of black scales.…”

Section: Suitability Of the Experimental Protocolmentioning

confidence: 99%

“…In an earlier report, we suggested that staining is actually a change in the status of body surface conditions into those of the ocular side and that the staining of these areas is irreversible [6]. Although staining is effectively prevented by use of a sand substrate [6][7][8][9][10], an alternative method to prevent staining is needed because sand creates cleaning difficulties for hatcheries. Further, hatchery stocks experience another color anomaly called pseudoalbinism, in which a significant portion of the ocular side lacks pigmentation (due to absence of melanophores and xanthophores); however, this problem has been largely overcome by improvements in nutrition [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Transplantation of pigmented and non-pigmented scales into the ocular and blind sides of the Japanese flounder Paralichthys olivaceus, suggesting the presence of ocular-side characteristic inducer in pigmented scales

Isojima

Tagawa

2014

Fish Sci

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After metamorphosis, both eyes of the Japanese flounder Paralichthys olivaceus are located on its left side, with only the ocular side becoming pigmented. Staining, or hypermelanosis, occurs on the blind side at 2-3 months after metamorphosis, thereby lowering the market price of the fish. To understand the pigmentation expansion process, we performed scale transplantation between the blind and ocular sides of an individual. About 40 % of transplanted scales were successfully engrafted, regardless of donor or recipient site. When blind-side scales were transplanted to the ocular side, they became pigmented after 2 weeks, while no change was observed when the scales were transplanted to the blind side. Ocular-side scales did not lose pigment, regardless of the recipient site. However, after removal of transplanted ocular-side scales, pigmented scales regenerated after 3 weeks, even at blindside sites. Identical results were obtained when the stained area on the blind side was used as the recipient location. When an ocular-side scale with skin tissue was inserted under blind-side scales, the scales immediately above the transplanted area became pigmented, whereas ocular-side scales stripped of tissue did not induce pigmentation. These results strongly suggest the presence of an ocular-side characteristic inducer in pigmented scale tissues.

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Effects of sandy substrate and light on hypermelanosis of the blind side in cultured Japanese flounder Paralichthys olivaceus

Cited by 30 publications

References 8 publications

Hyperpigmentation in North Sea dab Limanda limanda. II. Macroscopic and microscopic characteristics and pathogen screening

Hyperpigmentation in North Sea dab Limanda limanda. II. Macroscopic and microscopic characteristics and pathogen screening

Pigmentation development in hatchery‐reared flatfishes

Transplantation of pigmented and non-pigmented scales into the ocular and blind sides of the Japanese flounder Paralichthys olivaceus, suggesting the presence of ocular-side characteristic inducer in pigmented scales

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