The aim of the study was to evaluate the variability of the percentage of medullated fibres, according to sex and location and to compare the colorimetric characteristics in white fibre from Huacaya and Suri alpaca. The study was carried out in two communities (Juntaya in the Oropesa district and San Juan in the Sabaino district) in the province of Antabamba, Apurímac region (Peru), located between 3950 and 4543 meters above sea level. In total, 451 (Huacaya = 410 and Suri = 41) fibre samples (10 g) were taken from the mid side area. The medullated fibres (%) and the mean fibre diameter (µm) were evaluated using the Fiber Med device. For the colour analysis, a spectrometer coupled to an integrating sphere was used and for the characterization of the chemical bands, an FTIR spectrophotometer. The percentage of total medullation, continuous medullation and strongly medullated fibres were...

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...