Examinando por Autor "Silva Chaves, Maiana"

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Does the addition of follicular fluid in the in vitro maturation medium increase the oocyte maturation and embryo production in alpacas?
(Springer, 2023-06-07) Contreras Huamani, Mijail; Guillén Palomino, Crissthel Yverlin; Laines Arcce, Irving Mitchell; Silva Chaves, Maiana; Magalhães Melo, Luciana; De Figueirêdo Freitas, Vicente José
In alpacas (Vicugna pacos), the high cost of in vitro embryo production is also a consequence of the use of several substances in the culture medium. In addition, embryo production rates in this species are still considered low. Thus, in attempt to reduce the cost and to improve the in vitro embryo production rates, this study evaluates the effect of adding follicular fluid (FF) in the in vitro maturation medium on oocyte maturation and subsequent embryo production. After ovary collection at the local slaughterhouse, the oocytes were recovered, selected, and allocated in experimental groups: standard maturation medium (G1) and simplified medium added by 10% FF (G2). The FF was acquired from follicles between 7- and 12-mm diameter. The cumulus cell expansion and the embryo production rates were analyzed by chi-square with p < 0.05. No differences (p > 0.05) were observed in maturation rate between G1 (66.36%) and G2 (63.12%) groups. Likewise, no significant difference (p > 0.05) was verified between G1 and G2 for morula (40.85 vs 38.45%), blastocyst (7.01 vs 6.93%), and total number of embryos (47.87 vs 45.38%). In conclusion, it was possible to simplify the medium used for in vitro maturation of alpaca oocytes resulting in embryo production rates similar to the standard medium.
Influence of reproductive season and testicular volume on seminal parameters of alpacas (Vicugna pacos)
(Springer Nature, 2025-05-22) Contreras Huamani, Mijail; Guillen Palomino, Crissthel Yverlin; Orellana Berrocal, Harumi Rebeca; Laines Arcce, Irwin Mitchell; Bellido Quispe, Dionet Keny; Acuña Leiva, Alex Yony; Silva Chaves, Maiana; de Figueirêdo Freitas, Vicente José
The male alpaca plays an important role in the reproductive process and, consequently, in genetic improvement. South American camelids (SACs) have a well-defined reproductive season, particularly in the Andean region. The objective was to evaluate the influence of reproductive and non-reproductive seasons, as well as testicular volume, on seminal parameters in alpacas. Nine healthy male alpacas, over 4 years old, were selected for this experiment. Semen samples were taken every two days using an artificial vagina incorporated into a dummy. The collected were in the reproductive (November to April) and non-reproductive (May to October) seasons, from breeders with testicular volumes that range between 63–70 cm3 and 83–94 cm3. The total number of ejaculates collected was 72 per season, with 8 samples collected from each male. Macroscopic aspects such as color, volume (ml), thread formation (cm) and foam (cm) were evaluated, in addition to microscopic aspects such as sperm motility (%), viability (%) concentration (sperm/ml) and total number of sperm. The results were analyzed with the Mann–Whitney non-parametric test, using the R 3.4.3 software, considering P < 0.05 as the significance level. A decrease in thread formation was observed in semen collected during the reproductive season compared to the non-reproductive season (P < 0.05). On the other hand, sperm motility and viability in semen collected during the reproductive period was higher (p < 0.05). Regarding testicular volume, alpacas with larger testicular volume had greater ejaculate volume, sperm concentration and total number of sperm (p < 0.05). Based on these results, it is possible to conclude that the semen of alpaca breeders is influenced by the season, and that testicular volume can predict their reproductive capacity, being a parameter to be considered when selecting the best breeding male.