The white donkey of Asinara (Sardinia- Italy) belongs to the local ethnic groups. It is reported in the Registry Book of the equine populations [Ministerial decree 27-7-1990] and in the Ethnographic Atlas of Italian horse and ass populations for the conservation of the genetic resources. Because of the animals geographical isolation and of their small number it is necessary to apply an appropriate strategy of conservation and valorisation. A clinical examination gave a positive picture to the hypothesis that albinism is the origin of the white colour of the animals coat. Aiming to verify this, from in 6 white and 1 grey asses biopsy samples of skin were taken to be analysed. They were stained with specific histological methods for melanin: a)Fontana-Masson’s silver staining; b)immuno-histo-chemical staining with policlonal antibodies against S-100 protein and c)with HMB45 to find activated melanocytes, if any. In the epidermis basal layer of the grey ass a wide presence of melanin and few melanocytes were observed. The melanin was completely absent in the white asses skin; moreover only in the youngest white donkey (8 months of age) a more large number of melanocytes was found compared with the others, this seems to be a hyperplasia, due to the inability of the cells to synthesise melanin. Increasing the animals age, this feed-back mechanism decreases and disappears as observed in the older white asses. The lack of skin melanin associated with the clinical pictures leads to the conclusion it is an oculo-cutaneous albinism.
La razza degli asinelli bianchi dell’Asinara, come indicato nel Registro Anagrafico delle popolazioni equine riconducibili a gruppi etnici locali [D. M. 27-7-1990] e nell’Atlante etnografico delle popolazioni equine ed asinine per la salvaguardia delle risorse genetiche, per le sue condizioni di isolamento geografico e per la sua esiguità numerica necessita di un adeguato piano di salvaguardia e valorizzazione. Per appurare un’eventuale forma di albinismo, quale responsabile del colore bianco del mantello, a completamento di particolareggiate visite cliniche individuali, sono stati analizzati prelievi bioptici cutanei di sei asinelli bianchi e di uno grigio dell’Asinara mediante metodiche istologiche specifiche per il pigmento melanico (impregnazione argentica) ed immunoistochimiche (antisieri immunoreagenti con i melanociti normali - proteina 100 - e con quelli attivati - HMB45). Nello strato basale dell’epidermide del soggetto grigio si sono riscontrati abbondante pigmento melanico e pochi melanociti. Negli asinelli bianchi, alle diverse età, non si è riscontrato pigmento melanico. Nel soggetto bianco più giovane si è osservato un numero più elevato di melanociti rispetto agli animali, più anziani nei quali è risultato simile a quello grigio. Quest’ultima osservazione può essere spiegata come risposta proliferativa iperplastica limitata alla prima fase di vita, che viene indotta con meccanismo di feed back dalla incapacità dei melanociti di sintetizzare pigmento. Tale risposta tende ad esaurirsi con l’avanzare dell’età dei soggetti. I rilievi clinici unitamente all’assenza completa di melanina cutanea permettono di inquadrare il fenomeno in un’espressione fenotipica di albinismo di tipo oculo-cutaneo.
Gli asinelli bianchi dell’Asinara: una razza di animali albini? IV Congresso Nazionale Biodiversità, Alghero 8-11 Settembre 1998 / Pinna, W.; Todde, P.; Cosseddu, G. M.; Iannelli, P.; Moniello, Giuseppe. - 3:(1998), pp. 1077-1080. (Intervento presentato al convegno IV Congresso Nazionale Biodiversità tenutosi a ALGHERO).
Gli asinelli bianchi dell’Asinara: una razza di animali albini? IV Congresso Nazionale Biodiversità, Alghero 8-11 Settembre 1998
MONIELLO, Giuseppe
1998-01-01
Abstract
The white donkey of Asinara (Sardinia- Italy) belongs to the local ethnic groups. It is reported in the Registry Book of the equine populations [Ministerial decree 27-7-1990] and in the Ethnographic Atlas of Italian horse and ass populations for the conservation of the genetic resources. Because of the animals geographical isolation and of their small number it is necessary to apply an appropriate strategy of conservation and valorisation. A clinical examination gave a positive picture to the hypothesis that albinism is the origin of the white colour of the animals coat. Aiming to verify this, from in 6 white and 1 grey asses biopsy samples of skin were taken to be analysed. They were stained with specific histological methods for melanin: a)Fontana-Masson’s silver staining; b)immuno-histo-chemical staining with policlonal antibodies against S-100 protein and c)with HMB45 to find activated melanocytes, if any. In the epidermis basal layer of the grey ass a wide presence of melanin and few melanocytes were observed. The melanin was completely absent in the white asses skin; moreover only in the youngest white donkey (8 months of age) a more large number of melanocytes was found compared with the others, this seems to be a hyperplasia, due to the inability of the cells to synthesise melanin. Increasing the animals age, this feed-back mechanism decreases and disappears as observed in the older white asses. The lack of skin melanin associated with the clinical pictures leads to the conclusion it is an oculo-cutaneous albinism.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.