Heritability of individual fiber medullation in Peruvian alpacas

Pinares, Rubén; Gutiérrez, Gustavo; Cruz, Alan; Morante, R.; Cervantes, I.; Burgos, A.; Gutiérrez, Juan Pablo

doi:10.1016/j.smallrumres.2018.04.007

Cited by 27 publications

(17 citation statements)

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“…They commented that independently of all these effects, the impact of these kemp and gare fibers was negligible in the finished product in ultra fine Merino sheep. Similar variations in medullation across all the diameter rank appeared also in Australian alpacas (Aylan-Parker and McGregor, 2002) and also Pinares et al (2018) reported that when observing alpaca fibers using a projection microscope, both fine but medullated fibers, and coarse but not medullated fibers were usually observed. They also found that the continuously strongly medullated fibers were found in the right skewed tail of the distribution, inferring that the thick fibers were mainly medullated.…”

Section: Discussionsupporting

confidence: 71%

“…Although there is a high PM variability in alpacas, the PM mean in the highly selected animals of Pacomarca experimental farm was found to be 37.31% in Huacaya genetic type and 32.74% in Suri genetic type (Table 1), higher percentages than those reported by Pinares et al (2018) in the males of the same highly selected Pacomarca experimental farm (24%). It was a similar value to that reported by Wang et al (2003) in Australian alpacas (32.28%), higher than the 24.4% value reported in another Australian alpaca population (Aylan-Parker and McGregor, 2002).…”

Section: Discussionmentioning

confidence: 82%

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Genetic parameters for medullated fiber and its relationship with other productive traits in alpacas

Cruz¹,

Morante²,

Gutiérrez

et al. 2019

Animal

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The alpaca fiber diameter (FD) varies from 18 to 36 μm, being the finer fiber categories highly appreciated. However, the alpaca fiber presents some limitations in the textile industry due to the high incidence of fiber medullation and diameter variability, both reduces the comfort feeling of the garments. Decreasing or even removing medullation could be a possible selection objective in alpaca breeding programs for increasing economic value of the alpaca fiber. Therefore, the present work aimed to estimate genetic parameters regarding medullation traits, as well as the genetic correlations with other economical important traits, to be able to select the appropriate criteria to reduce or remove medullation on alpaca fiber and help to reduce the prickle factor in the garments. The data was collected from 2000 to 2017 and belonged to the Pacomarca experimental farm. There were 3698 medullation records corresponding to 1869 Huacaya and 414 Suri genetic types. The fiber samples were taken from the mid side, and were analyzed in an OFDA 100® device. The traits analyzed were percentage of medullation (PM), medullated fiber diameter (MFD), FD, standard deviation of FD, greasy fleece weight as fiber traits; density, crimp in Huacaya and lock structure in Suri, head conformation, leg coverage as morphological traits; weaning weight and age at first calving as secondary and functional traits. Genetic parameters were estimated via a multitrait restricted maximum likelihood. The heritabilities for PM and MFD were 0.225 and 0.237 in Huacaya genetic type and 0.664 and 0.237 in Suri genetic type, respectively; heritabilities for other traits were moderate for productive and morphological traits, and low to moderate for secondary and functional traits. The genetic correlations PM–FD and MFD–FD were high and favorable in both genetic types, between 0.531 and 0.975; the genetic correlation PM–MFD was 0.121 in Huacaya and 0.427 in Suri. The rest of genetic correlations with other traits were in general moderate and favorable. The repeatabilities were 0.556 and 0.668 for PM, and 0.322 and 0.293 for MFD in Huacaya and Suri genetic types, respectively. As a conclusion, PM was identified to be a good selection criterion, probably combined in an index with FD to reduce prickling factor.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 82%

Genetic parameters for medullated fiber and its relationship with other productive traits in alpacas

Cruz¹,

Morante²,

Gutiérrez

et al. 2019

Animal

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“…Sin embargo, la alta variabilidad del porcentaje de fibras meduladas fragmentadas, discontinuas y continuas, aunado a que estas fibras se presentan en un rango amplio de finura (finas a gruesas) en el vellón de la alpaca podría explicar el bajo rendimiento del descerdado (Wang et al, 2008). Por otro lado, la selección es otra alternativa que permitiría reducir el porcentaje de fibras meduladas (Pinares et al, 2018). Así, el presente trabajo tuvo como objetivo determinar la variabilidad fenotípica del porcentaje de fibras…”

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“…Para fines de selección por PM y otras características de las fibras meduladas, se sugiere que la región del flanco (ijar) es la región más representativa (Aylan-Parker yMcGregor, 2002). como el incremento del porcentaje de fibras meduladas fragmentadas y no meduladas en el vellón de alpacas puede atribuirse a la selección dirigida para reducir el DMF que se practica en Pacomarca(Cervantes et al, 2010) Sánchez et al, 2016;Cruz et al, 2017;Pinares et al, 2018)…”

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Variabilidad fenotípica del porcentaje de fibras meduladas en el vellón de alpaca Huacaya

Pinares

Gutiérrez

Cruz³

et al. 2019

Rev. investig. vet. Perú

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El objetivo del estudio fue evaluar la variabilidad fenotípica del porcentaje de fibras meduladas de alpacas Huacaya, así como calcular la correlación fenotípica entre el diámetro medio de fibra (DMF) y el porcentaje de medulación total (PM). Se tomaron muestras de fibra de 36 alpacas Huacaya (machos entre 0.4 y 10.4 años) para determinar el DMF y el PM con el microscopio de proyección. El tipo de médula de las fibras fue considerada como no medulada, fragmentada, discontinua, continua y fuertemente medulada. Se observó una alta variabilidad fenotípica del PM entre alpacas y dentro de las muestras. El promedio ± desviación estándar del PM y DMF fue 32.56 ± 18.30% y 17.58 ± 2.52 µm para fibras no meduladas; 29.29 ± 11.67% y 21.49 ± 2.39 µm para fibras con medulación fragmentada; 14.01 ± 10.14% y 24.04 ± 2.40 µm para fibras con medulación discontinua; 23.90 ± 13.01% y 28.04 ± 3.10 µm para fibras con medulación continua; y 0.59 ± 0.44% y 50.85 ± 9.86 µm para fibras fuertemente meduladas, respectivamente. La correlación fenotípica entre el PM y el DMF fue 0.80, y entre el PM y el porcentaje de medulación continua fue 0.74. En conclusión, existe una alta variabilidad fenotípica del PM y de los porcentajes de fibras meduladas continuas, discontinuas y fragmentadas en el vellón de alpaca Huacaya. Las fibras finas tienen una baja frecuencia de médulas fragmentadas y discontinuas, mientras que las fibras más gruesas tienen una mayor frecuencia de médulas discontinuas y continuas.

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“…Há portanto uma correlação negativa entre a densidade folicular e a delicadeza das fibras. Quanto maior a densidade folicular, menor o diâmetro da fibra(TORRES DE JASAUI et al, 2007;MALONEY, 2011;VÉLEZ et al, 2016).A fibra interiormente no seu interior pode ser fortemente medulada, sendo a mesma contínua, fragmentada, interrompida ou simplesmente ausente(GERKEN, 2010;PINARES et al, 2018). Em fibras espessas o diâmetro da medula, pode apresentar uma oscilação entre 0.25% e 0.30% de diâmetro.…”

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>b<Arquitetura e estrutura da pelagem da Alpaca(>i<Vicugna pacos>/i<)>/b<

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Alpacas are mainly raised for fiber production, which is a highly valued product in the textile industry. Therefore the purpose of this project aims to evaluate morphological and quantitative aspects of alpaca´s coat in Huacaya and Suri breeds, comparing the structure and architecture of the skin forelimb lateral region, thoracic lateral region, and hind limb lateral region, with three sub-regions: scapular, costal and lateral femoral respectively. For this project, 8 mm biopsies were collected from the coat of 12 alpacas, from the Pacomarca Experimental Fund, located in the city of Puno-Peru. The samples were weighed, immersed in 10% aqueous formaldehyde solution and then processed. After that, they were cut into fragments of 2 mm each, in order to obtain random samples for Stereological analyzes. Hematoxylin and Eosin, Picrosirius Red and Masson's Trichrome stains were used for the microscopic analysis. This last staining was also required for Stereological analysis. After obtaining the images, a slide with the points system was added to each sample in order to count the structures to be evaluated. Subsequently, markers for type I, III and IV collagen proteins were used to perform immunohistochemical analysis, as well as for S100. The structures found in the integumentary system of alpacas were the components of the skin, such as the epidermis, the dermis, and separating the two structures, the basal lamina. In the dermis it was possible to observed the sebaceous glands and sweat glands, as well as the follicular groups formed by primary follicles and secondary hair follicles in abundance. From each of these follicles a hair emerged called fiber. One of the factors used for this evaluation was the observation of the fibers diameter, which was measured in samples obtained from the costal region of the alpacas, and carried out by means of scanning electron microscopy technique. Measurements of 12.65 μm up to 55.00 μm were obtained. It was possible to observed fibers that had marrow and others that did not have marrow, making it possible to differ them in the three layers that composed the hair. Together, with the marrow, they composed the cortex and the cuticle, in addition to the layers of the hair follicle. Extracellular matrix proteins were also evaluated, in which type III collagen fibers were found, which marked only the collagen and reticular fibers present in the dermis and presenting a different marking when compared to the other collagens including S100 protein. The volume of the skin, dermis, follicular groups, sebaceous glands and sweat glands were evaluated through Stereological analysis, among the three body regions of each group of alpacas at a significance level of p <0.05, resulting in differences in the mean volume of the dermis and the mean volume of follicular groups in dark-colored Suri alpacas. The four groups of alpacas for each body region were also compared, with a significance level of p<0.05, and p>0.05 for the mean volumes of skin and dermis in the lateral femoral region.

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Heritability of individual fiber medullation in Peruvian alpacas

Cited by 27 publications

References 29 publications

Genetic parameters for medullated fiber and its relationship with other productive traits in alpacas

Genetic parameters for medullated fiber and its relationship with other productive traits in alpacas

Variabilidad fenotípica del porcentaje de fibras meduladas en el vellón de alpaca Huacaya

>b<Arquitetura e estrutura da pelagem da Alpaca(>i<Vicugna pacos>/i<)>/b<

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