Browsing by Author "Machaca, Virgilio"

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    Fiber quality at dehairing and characterization of skin follicle parameters in Peruvian Q’ara llamas
    (Frontiers in Animal Science, Animal Physiology and Management, 2026-03-12) Machaca, Virgilio; Pinares, Rubén; Lozano, Franklin; Quispe Quispe, Arturo; Machaca, Alex D.; Bustinza Choque, A. Víctor
    Introduction: Although Q’ara llama fleece was previously believed to lack quality attributes, the down fiber obtained during first shearing is of high quality. However, little is known about skin follicle parameters in Peruvian Q’ara llamas. In this context, the objective of this research was to compare fiber quality after manual dehairing and to characterize skin follicle parameters by body site, age, and sex. Methods: A total of 240 fiber samples were collected from the shoulders, mid-side, and rump of 80 Q’ara llamas, taking into account their age category and sex. Each unprocessed fiber sample was manually dehaired, yielding two subsamples of 240 each: down fibers and guard hairs. Only the unprocessed and down fibers were used for fiber measurements. According to IWTO-47 standards, an OFDA 2000 was used to measure mean fiber diameter, standard deviation, coefficient of variation, comfort factor, and fiber curvature. Skin biopsies were collected from 65 llamas under local anesthesia using an 8 mm punch to analyze follicle densities and the secondary-to-primary ratio. We performed Type I and the Tukey test (α = 0.05) on transformed data. Spearman’s correlation was applied without data transformation. Results and discussion: Manual dehairing improved textile fiber quality by reducing the diameter by 1.91 µm and the coefficient of variation by 3.05%. It also increased the comfort factor by 4.79% and fiber curvature by 3.49°/mm. Secondary follicle density (16.80 follicles per mm2) and secondary-to-primary follicle ratio (6.28) were similar across sex and body site. However, skin follicle density decreased in older llamas. There was a strong negative correlation (-0.82) between mean fiber diameter and comfort factor. Mean fiber diameter was negatively correlated with fiber curvature, total follicle density, and secondary to primary follicle ratio. However, comfort factor was positively correlated with fiber curvature, total follicle density, and secondary-to-primary follicle ratio. Total follicle density was positively associated with secondary-to-primary follicle ratio (0.52). Conclusion: Dehairing improves fiber quality. The main factor affecting fiber quality and skin follicles is age. Young Q’ara llamas have higher follicle density and produce down fiber with a diameter of 22.61 µm. However, body site and sex do not influence quality. The favorable relationship between fiber diameter and follicle density allows for the selection of high-quality fiber.
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    Microencapsulated essential oils influence the growth and foregut histomorphometry of Nile tilapia (Oreochromis niloticus) fingerlings
    (Veterinary and Animal Science, Elsevier, 2026-03-12) Roldan Juarez, Jesús; Pinares, Rubén; Smith, Carlos E.; Llerena, Cielo A.; Machaca, Virgilio; Pizarro, Dante M.
    Essential oils supplementation has potential growth-promoting, antibacterial, and immunostimulatory effects for various fish species. Dietary supplementation with essential oils improves Nile tilapia's growth and intestinal morphology. The aim of the study was to assess the effect of supplementation with microencapsulated essential oils (MEOs) containing cinnamaldehyde (53.9 %), thymol (24.2 %), and carvacrol (18.7 %) in Nile tilapia fingerlings on growth parameters and foregut histomorphometry. Six thousand fishes with initial body weights and lengths of 1.20 ± 0.32 g and 2.03 ± 0.40 cm, respectively, were reared in two separate 60 m3 circular tanks (control and supplemented with 500 mg/kg of MEOs) at a 5 kg/m3 density. Growth parameters included weight and length. Ten foregut samples per tank were collected at 0-, 15- and 30-days post-treatment. The histological analysis involved the size of intestinal folds and the number of goblet cells. Our results showed that fingerling growth parameters such as final body weight and length increased by 16.9 % and 10.43 %, respectively, with MEOs supplementation compared to the control group. Furthermore, histomorphometry results showed that the supplementation of MEOs led to a significant increase in the growth of both the width and length of intestinal folds and the number of goblet cells (p < 0.05). In conclusion, the early supplementation with MEOs improved the number, length, and width of intestinal folds and increased the number of goblet cells, positively influencing intestinal morphology and health. Additionally, MEOs improved growth parameters in Nile tilapia at 30 days of supplementation.
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    Relationship between fiber quality and follicle density in Ch’aku llamas (Lama glama)
    (Tropical Animal Health and Production, 2026-03-12) Machaca, Virgilio; Málaga, Julio; Gómez Quispe, Oscar
    In the high altitudes of the Andes, llama breeders shear the fiber from their animals, obtaining fleeces for many purposes. Dehairing the fleece of these animals is a viable alternative to improving the quality and value of the fleece. The study examined the attributes of fiber quality and pilose follicle of dehaired and non-dehaired fleece from Ch’aku llamas and the relationship among these characteristics. From 80 animals, 480 fleece samples (240 dehaired and 240 non-dehaired), and 198 skin biopsies of dehaired specimens were collected. The data was analyzed using a model that contain fleece type effect, age group effect, sex effect, body region effect, and their respective interactions. Also, the Spearman correlation between fiber quality attributes and pilose follicle traits was calculated. The findings showed that non-dehaired fiber had a diameter of 22.01 ± 0.17 µm, while dehaired fiber measured 20.85 ± 0.16 µm. Removing the hair from the fiber resulted in a decrease in the average fiber diameter, standard deviation, and coefficient of variation while increasing the comfort factor and curvature index. The age group had an impact on primary follicles, secondary follicles, follicular density, and follicular index. Furthermore, gender influenced secondary follicles and follicular density, whereas body region affected secondary follicles and follicular density. Negative correlations were observed between mean of follicular density (MFoD) and mean fiber diameter (MFD), as well as curvature ratio (CRV), whereas a positive correlation was found between mean of follicular index (MFoI) and MFoD, and a negative correlation was noted between MFoI and CRV. It is concluded that the dehairing of the Ch’aku llama fiber improves the quality of the fleece.