ABSTRACT Single nucleotide polymorphisms are variations of a single nucleotide base pair and can be associated to phenotypic characteristics. This study aimed to determine the association of CAPN1 and CAST gene polymorphisms with the tenderness of Creole cattle meat from the Amazonas region, Peru. The texture profile (adhesiveness, cohesiveness, Warner-Bratzler shear force, elasticity, gumminess, and chewiness) of 100 animals was determined in 100 g of Longissimus dorsi et lumborum muscle. Allelic frequencies, genotypic frequencies, and Hardy-Weinberg equilibrium (HWE) of calpain (CAPN-316, CAPN-530) and calpastatin (CAST-2959) gene polymorphisms were studied. Allelic and genotypic frequencies were calculated, as well as the Hardy-Weinberg equilibrium with the Chi-square test. The texture profile of each group of samples corresponding to a polymorphism was compared with the Duncan’s test and the t-test for independent samples (p < 0.05). Genotypic frequencies were 78 % GG and 22 % CC for CAPN-316; 68 % GG, 5 % GA, and 27 % AA for CAPN-530; and 74 % AA, 18 % AG, and 8 % GG for CAST-2959. The CAPN-316, CAPN-530, and CAST-2959 polymorphisms were not in Hardy-Weinberg equilibrium. The CC genotype of CAPN-316 marker influences meat tenderness on day 21 of meat aging. In contrast, the GG genotype of CAST-2959 marker affects meat tenderness at days 14 and 21 of meat aging concerning the other genotypes.

Resumen Las propiedades fisicoquímicas como terneza, color, jugosidad, sabor, marmoleo, pH y capacidad de retención de agua, son consideradas como los atributos que tienen mayor importancia en la calidad de la carne. El manejo post mortem influye en el funcionamiento del sistema proteolítico de las enzimas µ-calpaínas y calpastatinas, que están codificadas por los genes CAPN1 y CAST, respectivamente. Esta revisión muestra las asociaciones de los polimorfismos CAPN1 y CAST con el fin de explicar las propiedades fisicoquímicas antes mencionadas, que determinan las características relacionadas con la calidad de la carne. Existen polimorfismos de CAPN1 y CAST asociados a propiedades fisicoquímicas particulares de la carne, pero no todos los polimorfismos se asocian con las propiedades mencionadas. La actividad del sistema proteolítico de las enzimas varía según el manejo peri y post mortem. La presencia o ausencia de un polimorfismo varía entre razas. Por consiguiente, las asociaciones de polimorfismos de nucleótido simple con las propiedades fisicoquímicas de la carne mencionadas en esta revisión podrían ayudar a mejorar los indicadores de calidad de la carne bovina.

Abstract Physicochemical properties such as tenderness, color, juiciness, flavor, marbling, pH and water retention capacity, are considered the most important attributes in the meat quality. Posmortem management influences the functioning of the proteolytic system of the enzymes calpains and calpastatins, which are encoded by CAPN1 and CAST genes, respectively. This review displays the associations of CAPN1 and CAST polymorphisms in order to explain the aforementioned physicochemical properties, which determine the characteristics relate to the beef quality. There are CAPN1 and CAST polymorphisms associated with particular physicochemical properties of meat, but not all polymorphisms are associated with the mentioned properties. The activity of enzymes proteolytic system varies according to peri and posmortem management. The presence or absence of a polymorphism varies between races. Therefore, the associations of single nucleotide polymorphisms with the physicochemical properties of meat mentioned in this review could help to improve the quality indicators of beef.

Resumo Propriedades físico-químicas como maciez, cor, suculência, sabor, marmorização, pH e capacidade de retenção da água, são consideradas os atributos mais importantes na qualidade da carne. O manejo pós-morte influencia o funcionamento do sistema proteolítico das enzimas calpaína e calpastatina, que são codificadas pelos genes CAPN1 e CAST, respectivamente. Esta revisão mostra as associações dos polimorfismos CAPN1 e CAST para explicar as propriedades físico-químicas citadas, que determinam as características relacionadas à qualidade da carne. Existem polimorfismos CAPN1 e CAST associados a propriedades físico-químicas específicas da carne, mas nem todos os polimorfismos estão associados às propriedades mencionadas. A atividade das enzimas do sistema proteolítico varia de acordo com o manejo peri e pos-mortem. A presença ou ausência de um polimorfismo varia entre as raças. Portanto, as associações de polimorfismos de nucleotídeo único com as propriedades físico-químicas da carne mencionadas nesta revisão poderiam ajudar a melhorar os indicadores de qualidade da carne bovina.

ABSTRACT The aim of this study was to determine the influence of a co-culture system with cumulus oophorus cells on the quality of bovine embryos produced in vitro, based on their viability. Ovaries from crossbred bovine slaughtered at the Chachapoyas Municipal Benefit Centre, Amazonas, Peru, were used. Oocytes aspirated from 2-6 mm follicles were matured in TCM-199 medium for 24 hours, in a humidified atmosphere with 6% CO and 38.5 °C. The maturation state was determined by the nuclear stage through aceto-orcein staining. The mature oocytes were fertilized in vitro with frozen semen from Angus bulls for 18 hours. The presumed zygotes were randomly distributed for development in one group in medium with co-culture and another in medium without co-culture (control). The embryonic quality was determined based on the enzymatic activity and DNA damage of the embryos on the seventh day of culture, using the fluorochromes fluorescein diacetate (FDA) and propidium iodide (PI), respectively. No significant association was found in the number of embryos produced in vitro, but there was a significant difference in embryonic viability in favour of the system with co-culture (p<0.05). The use of co-cultures with cumulus oophurus cells improves viability and, therefore, embryonic quality, without influencing the rate of embryo production in vitro.

RESUMEN El estudio tuvo como objetivo determinar la influencia de un sistema de co-cultivo con células del cumulus oophorus sobre la calidad de embriones bovinos producidos in vitro en función a su viabilidad. Se utilizaron ovarios de bovinos hembra cruzadas, sacrificadas en el Centro de Beneficio Municipal de Chachapoyas, Amazonas, Perú. Los ovocitos aspirados de folículos de 2-6 mm fueron madurados en medio TCM-199 por 24 horas, en una atmósfera humidificada con 6% de CO2 y a 38.5 °C. El estado de maduración fue determinado mediante el estadio nuclear a través de tinción aceto- orceína. Los ovocitos maduros se fertilizaron in vitro con semen congelado de toros Angus durante 18 horas. Los presuntos cigotos fueron distribuidos aleatoriamente para su desarrollo en un grupo en medio con co-cultivo y otro en medio sin co-cultivo (control). Se determinó la calidad embrionaria en función a la actividad enzimática y daño al ADN de los embriones al séptimo día del cultivo, mediante los fluorocromos diacetato de fluoresceína (FDA) y yoduro de propidio (PI), respectivamente. No se encontró asociación significativa en la cantidad de embriones producidos in vitro, pero hubo diferencia significativa en viabilidad embrionaria a favor del sistema con co-cultivo (p<0.05). El uso de co-cultivos con células de cumulus oophurus mejora la viabilidad y, por lo tanto, la calidad embrionaria, sin influir en la tasa de producción de embriones in vitro.

ABSTRACT In vitro embryonic development and conception rate of bovine oocytes (Bos indicus) vitrified in mature stage were evaluated. The ovaries were collected from Brahman cows from the Bagua Grande municipal slaughterhouse (Amazonas, Peru). The collected ovaries were transferred to the laboratory in 0.9% NaCl solution with 0.025 mg/ml streptomycin. The oocytes were aspirated, matured in vitro and vitrified. The nuclear stage of the oocytes was determined with aceto-orcein staining. Among them, 12.5% exhibited germinal vesicle, 5% reached metaphase I (MI) and 82.5% reached metaphase II (MII) of nuclear stage. The potential for embryonic development was evaluated on day 7 of the in vitro culture. It was obtained 5.8% of morulae and 10.4% blastocysts in the experimental group (n=154 vitrified oocytes) and 11.6% of morulae morulae and 24.9% of blastocysts in the control group (n=181 oocytes without vitrification process). Finally, 14 embryos produced from vitrified oocytes were transferred in recipient cows, reaching the embryonic vesicle 35 days after transfer in three cows (21.4%).

RESUMEN Se evaluó el desarrollo embrionario in vitro y la tasa de concepción a partir de ovocitos bovinos (Bos indicus) vitrificados en estadio maduro. Los ovarios fueron co- lectados de vacas Brahman del camal municipal de Bagua Grande, Amazonas, Perú. Los ovarios colectados fueron trasladados al laboratorio en solución NaCl 0.9% con 0.025 mg/ml de estreptomicina. Los ovocitos fueron aspirados, madurados in vitro y vitrificados. Se determinó el estadio nuclear de los ovocitos con tinción aceto-orceína. El 12.5% exhibió vesícula germinal, el 5% alcanzó metafase I (MI) y el 82.5% alcanzó metafase II (MII) de estadio nuclear. El potencial de desarrollo embrionario fue evaluado al séptimo día de cultivo in vitro. Se obtuvo 5.8% de mórulas y 10.4% de blastocistos en el grupo experimental (n=154 ovocitos vitrificados) y 11.6% de mórulas y 24.9% de blastocistos en el grupo control (n=181 ovocitos sin proceso de vitrificación). Finalmente, 14 embriones producto de ovocitos vitrificados fueron transferidos en vacas receptoras, llegando a formar la vesícula embrionaria a los 35 días de la transferencia en tres vacas (21.4%).