Growth Trait Heredity in Two Cavy Sublines Native to the Ecuadoran Mountain Range

Background: No studies have been published on South American cavy preservation and breeding programs; therefore, the aim of this article was to analyze the genotypic and environmental factors that act upon the growth traits of a South American native cavy line found in the Ecuadoran Mountain Range. Methods: The study took place on Irquis experimental farm, from the Faculty of Agricultural Sciences, University of Cuenca, using two native cavy sublines from rural breeders in provinces Azuay and Cañar. Weight per age and daily weight gain (g) were analyzed by a mixed variance analysis of litter size (5), season (semester), sex, and parturition number of the mother as fixed effects, using software R 3.4.4. The random effects were made by sub-lines Azuay (1) and Cañar (2), and their male parents. The basic statistical values were determined. Results: Birth weight, weaning weight, and weight at 90 days in grams, were 110.2 ± 1.81, 117.0 ± 1.44; 212.2 ± 4.30 and 221.13 ± 3.38; 540.7 ± 12.01, and 659.1 ± 9.44, respectively. The heredity values for these traits were 0.09 ± 0.101, 0.34 ± 0.201, and 0.11 ± 0.111. Besides, weight was analyzed at 30, 45, 60, 75, and 90 days after birth, which included gains at every age. The BLUP predictors for the parents of the two sub-lines were determined. Variation and heritability allowed for selection of weight at weaning and at 90 days. Conclusions: This line showed low growth levels, though the variations observed were adequate. Their heredity might lead to the expected favorable results, provided a selection program is implemented in the mid-term.Background: No studies have been published on South American cavy preservation and breeding programs; therefore, the aim of this article was to analyze the genotypic and environmental factors that act upon the growth traits of a South American native cavy line found in the Ecuadoran Mountain Range. Methods: The study took place on Irquis experimental farm, from the Faculty of Agricultural Sciences, University of Cuenca, using two native cavy sublines from rural breeders in provinces Azuay and Cañar. Weight per age and daily weight gain (g) were analyzed by a mixed variance analysis of litter size (5), season (semester), sex, and parturition number of the mother as fixed effects, using software R 3.4.4. The random effects were made by sub-lines Azuay (1) and Cañar (2), and their male parents. The basic statistical values were determined. Results: Birth weight, weaning weight, and weight at 90 days in grams, were 110.2 ± 1.81, 117.0 ± 1.44; 212.2 ± 4.30 and 221.13 ± 3.38; 540.7 ± 12.01, and 659.1 ± 9.44, respectively. The heredity values for these traits were 0.09 ± 0.101, 0.34 ± 0.201, and 0.11 ± 0.111. Besides, weight was analyzed at 30, 45, 60, 75, and 90 days after birth, which included gains at every age. The BLUP predictors for the parents of the two sub-lines were determined. Variation and heritability allowed for selection of weight at weaning and at 90 days. Conclusions: This line showed low growth levels, though the variations observed were adequate. Their heredity might lead to the expected favorable results, provided a selection program is implemented in the mid-term

Influence of Penile Spicules of Covies(Cavia porcellus)on their Sexual Behavior, Fertility and Sperm Quality

This research took place in canton Cuenca, province of Azuay, Ecuador, located on UTM 717386 x 9675751, 2 714 meters above sea level, with a mean temperature of 14°C. The study determined the influence of penile spicules on sexual behavior, fertility and sperm quality parameters in cavies (Cavia porcellus), raised on the Ecuadoran highlands. A number of 5 whole males (with penile spicules), and other 5 males with their spicules removedwere included in the study, along with 40 nulliparous females, type A, pelage type 1. The pregnancy percentage of females that copulated with extirpated males decreased 65% in relation to the control group (P<0.05). However, the sexual behavior pattern and sperm quality of the two groups in the study were similar (P>0.05). Therefore, the study concluded that extirpation of the penile spicules has effects on fertility, but not on sexual behavior and sperm quality

Colloidal Centrifugation for Dog Sperm Selection Prior Cryopreservation with Glycerol.

Background: Dog ejaculates are produced in three fractions: the first and third fractions contain prostatic fluid, which is harmful for cryopreservation. The second fraction is spermatozoa-rich. Collecting the second fraction of the ejaculate is complex; hence, colloidal centrifugation plus the addition of glycerol at three different concentrations (4, 6, and 8%) as cryoprotectant was evaluated as a method for sperm selection. Methods: In this study, 72 seminal samples from 6 crossbred dogs were evaluated at the University of Cuenca-Ecuador. Two aliquots were made from each sample, one for conventional centrifugation (Group 1), the other for colloidal centrifugation (Group 2). After centrifugation, each aliquot was subdivided into three parts, and 4, 6, and 8% glycerol were added, respectively. Three sperm evaluations were made (initial, pre-thawing, and post-thawing). Results: Sperm concentration was similar between the initial sample (IS) and Group 1 (P>0.05) after centrifugation, whereas fewer spermatozoa where observed in Group 2 (P <0.05). Evaluation of pre-thawing individual progressive motility (IPM) revealed that the spermatozoa in Group 1 underwent a 30% motility reduction in comparison to the IS and Group 2. Post-thawing IPM within the groups with different concentrations of glycerol (4, 6, and 8%) which underwent previous centrifugation with Percoll (Group 2), showed statistical differences (P <0.05). However, the HOS test produced similar percentages. Conclusions: Colloidal centrifugation prior freezing ensures better sperm selection and purification.Background: Dog ejaculates are produced in three fractions: the first and third fractions contain prostatic fluid, which is harmful for cryopreservation. The second fraction is spermatozoa-rich. Collecting the second fraction of the ejaculate is complex; hence, colloidal centrifugation plus the addition of glycerol at three different concentrations (4, 6, and 8%) as cryoprotectant was evaluated as a method for sperm selection. Methods: In this study, 72 seminal samples from 6 crossbred dogs were evaluated at the University of Cuenca-Ecuador. Two aliquots were made from each sample, one for conventional centrifugation (Group 1), the other for colloidal centrifugation (Group 2). After centrifugation, each aliquot was subdivided into three parts, and 4, 6, and 8% glycerol were added, respectively. Three sperm evaluations were made (initial, pre-thawing, and post-thawing). Results: Sperm concentration was similar between the initial sample (IS) and Group 1 (P>0.05) after centrifugation, whereas fewer spermatozoa where observed in Group 2 (P <0.05). Evaluation of pre-thawing individual progressive motility (IPM) revealed that the spermatozoa in Group 1 underwent a 30% motility reduction in comparison to the IS and Group 2. Post-thawing IPM within the groups with different concentrations of glycerol (4, 6, and 8%) which underwent previous centrifugation with Percoll (Group 2), showed statistical differences (P <0.05). However, the HOS test produced similar percentages. Conclusions: Colloidal centrifugation prior freezing ensures better sperm selection and purification

Comparison between Ecuadoran Genotypes of Cavy Litters (Cavia porcellus) and Cavies Bred in Peru

Background: The threat of extinction posed on different unprotected genotypes from the Andean Ranges of Ecuador is calling for new studies and preservation measures to keep the biological diversity of the area, which has enormous perspectives for human nutrition. The aim of this paper was to compare the sizes and weights up to the weaning stage of native Ecuadoran cavy litters in Azuay province, with the Peruvian-bred line. Methods: The study took place on Irquis experimental farm, belonging to the Faculty of Agricultural Sciences, University of Cuenca, Ecuador. The database was based on the records of breeding animals screened among farmers from Azuay and Cañar, and it included their phenotypic traits. Results: No significant differences were observed in the month of parturition, or the number of parturitions, or the genotype regarding the size of the litter at weaning. The data from Azuay and Peru were similar in terms of litter size at birth (3.1 and 3.2, respectively). However, it was higher regarding litter weight at birth and weaning (432 and 837 g, compared to the 313 and 570 g from Azuay, but no different from Cañar). Conclusions: The native genotypes from Azuay and Cañar were inferior to the Peruvian genotype, in terms of birth weight and weaning weight. Azuay was no different from Peru, according to litter size at birth or weaning. The potential observed in this genotype should be further developed.Background: The threat of extinction posed on different unprotected genotypes from the Andean Ranges of Ecuador is calling for new studies and preservation measures to keep the biological diversity of the area, which has enormous perspectives for human nutrition. The aim of this paper was to compare the sizes and weights up to the weaning stage of native Ecuadoran cavy litters in Azuay province, with the Peruvian-bred line. Methods: The study took place on Irquis experimental farm, belonging to the Faculty of Agricultural Sciences, University of Cuenca, Ecuador. The database was based on the records of breeding animals screened among farmers from Azuay and Cañar, and it included their phenotypic traits. Results: No significant differences were observed in the month of parturition, or the number of parturitions, or the genotype regarding the size of the litter at weaning. The data from Azuay and Peru were similar in terms of litter size at birth (3.1 and 3.2, respectively). However, it was higher regarding litter weight at birth and weaning (432 and 837 g, compared to the 313 and 570 g from Azuay, but no different from Cañar). Conclusions: The native genotypes from Azuay and Cañar were inferior to the Peruvian genotype, in terms of birth weight and weaning weight. Azuay was no different from Peru, according to litter size at birth or weaning. The potential observed in this genotype should be further developed

Espículas peneanas del cobayo (Cavia porcellus), influencia sobre el comportamiento sexual, fertilidad y calidad espermática

La investigación se realizó en el cantón Cuenca, provincia del Azuay-Ecuador. Coordenadas UTM 717 386 x 967 5751, altura 2 714 m s.n.m., temperatura promedio de 14 °C . El estudio determinó la influencia de las espículas peneanas sobre el comportamiento sexual, la fertilidad y parámetros de calidad espermática en cobayos (Cavia porcellus) criados en el altiplano ecuatoriano. Se utilizaron 5 machos enteros (con espículas peneanas), 5 machos extirpados las espículas y 40 hembras nulíparas, conformación Tipo A y pelaje tipo 1. Se determinó que el por ciento de preñez de las hembras copuladas con machos extirpados las espículas peneanas disminuía en 65 % en relación al grupo control (P < 0,05). Sin embargo, el patrón de comportamiento sexual y la calidad espermática de los dos grupos en estudio fue similar (P > 0,05). Por lo tanto, se concluye que la extirpación de las espículas peneanas influye en la fertilidad, pero no en el comportamiento sexual y calidad espermática.Abstract This research took place in canton Cuenca, province of Azuay, Ecuador, located on UTM 717 386 x 967 5751, 2 714 meters above sea level, with a mean temperature of 14 °C . This study determined the influence of penis spicules on sexual behavior, fertility and sperm quality parameters in cavy (Cavia porcellus), raised on the Ecuadorian highlands. A number of 5 whole males (with penis spicules) were included in the study. Also, included were 5 males with their spicules removed, and 40 multiparous females, conformation type A, pelage type 1. The pregnancy percentage of females that copulated with extirpated males decreased 65 % in relation to the control group (P < 0.05). However, the sexual behavior pattern and sperm quality of the two groups in the study were similar (P > 0.05). Therefore, the study concluded that extirpation of the penis spicule has effects on fertility, but not on sexual behavior and sperm quality

Heredabilidades de rasgos de crecimiento de dos sublíneas de cuyes nativos de la sierra ecuatoriana

Background: There are no studies that allow developing these programs for their conservation and genetic improvement of South American cobays. The objective of this article was analyze genotypic and environmental factors that influence the growth traits of a native line of guinea pigs from the south of the Ecuadorian highlands. Methods: The work was carried out in the experimental farm of Irquis of the Faculty of Agricultural Sciences of the University of Cuenca, with guinea pigs belonging to two native sublines originating from rural breeders of the provinces of Azuay and Cañar. The weight-for-age traits and the daily weight gains measured in grams were analyzed using a mixed variance analysis model with the fixed effects; size of litter (5), time (semester), sex and number of delivery of the mother with software R 3.4.4. The sub-lines Azuay (1) and Cañar (2) and the parents within sublines formed the random effects. The basic statisticians were determined. Results: The weights at birth, at weaning and at 90 days, measured in grams, were 110.2 ± 1.81, respectively, and 117.0 ± 1.44; 212.2 ± 4.30 and 221.13 ± 3.38; 540.7 ± 12.01 and 659.1 ± 9.44. The heritabilities for these characters were 0.09 ± 0.101; 0.34 ± 0.201 and 0.11 ± 0.111. In addition, weights were analyzed at 30; Four. Five; 60; 75 and 90 days of births and earnings among all ages. The BLUP predictors were determined for the parents of both su-blíneas. Variation and heritabilities allow to apply selection in the weight at weaning and at 90 days. Conclusions: The line showed low growth levels, but there is enough variation and its heritabilities would allow to expect favorable progress in case of a medium-term selection program.Antecedentes: No existen estudios que permitan desarrollar esos programas para su conservación y mejoramiento genético de cobayos suramericanos. El objetivo de este artículo fue analizar factores genotípicos y ambientales que influyen en los rasgos de crecimiento de una línea nativa de cuyes del sur de la sierra ecuatoriana. Métodos: El trabajo se llevó acabo en la granja experimental de Irquis de la Facultad de Ciencias Agropecuarias de la Universidad de Cuenca, con cobayos pertenecientes a dos sublíneas nativas originarias de criadores rurales de las provincias de Azuay y Cañar. Los rasgos de pesos por edad y las ganancias en peso diario medidos en gramos fueron analizados mediante un modelo de análisis de varianza mixto con los efectos fijos; tamaño de la camada (5), época (semestral), sexo y número de parto de la madre con el software R 3.4.4. Las sublíneas Azuay (1) y Cañar (2) y los padres dentro de sublíneas conformaron los efectos aleatorios. Se determinaron los estadígrafos básicos. Resultados: Los pesos al nacer, al destete y a los 90 días, medidos en gramos, fueron 110,2 ± 1,81, respectivamente, y 117,0 ± 1,44; 212,2 ± 4,30 y 221,13 ± 3,38; 540,7 ± 12,01 y 659,1 ± 9,44. Las heredabilidades para estos caracteres fueron 0,09 ± 0,101; 0,34 ± 0,201 y 0,11 ± 0,111. Además, se analizaron los pesos a los 30; 45; 60; 75 y 90 días de nacidos y las ganancias entre todas las edades. Se determinaron los predictores BLUP para los padres de ambas sublíneas. La variación y las heredabilidades permiten aplicar selección en el peso al destete y a los 90 días. Conclusiones: La línea mostró niveles de crecimiento bajos, pero hay suficiente variación y sus heredabilidades permitirían esperar progresos favorables en caso de realizarse un programa de selección a mediano plazo

Removal of Penile Spicules of Covies (Cavia porcellus) and its Effect on Weight Gain and Aggressiveness

This research took place on Irquis Farm, University of Cuenca, Victoria del Portete parish, Cuenca canton, prov-ince of Anzuay, Ecuador. The effects of penile spicule extirpation on weight gain and aggressiveness, and damage caused to the carcass at the beginning of growing/fattening were studied. The study consisted of three treatments: whole animals without castration, used as controls (T1); animals with extirpation of the glans´s spicules (T2); and chemically castrated animals, using 0.5 ml of 2% alcohol with iodine, directly injected in each testicle (T3). A total of 90 animals were included, following a randomized block design with six treatments and five replicas. The diet consisted of forage mixture of 33-35% dry matter, and a commercial feed supplement administered ad libitum. A co-variance analysis (ANACOVA) was made using the initial weight as co-variable. The final weight was significantly influenced by the treatment; the Tukey´s test resulted in higher final weight in T2, followed by T1. Their behavior was significantly different from T3 (P < 0.05). In relation to aggressiveness expressed in carcass damage, no signifi-cant differences were observed, according to Chi-square test (P > 0.05)

Morfometría de la gónada masculina y espermatozoides de cobayos (Cavia porcellus) nativo y mejorado del sur de Ecuador

The aim of this research was to describe the morphometry of the testicles and sperm of guinea pigs (Cavia porcellus) of two genetic groups, native and improved, from southern Ecuador. Twenty-two native and 20 improved guinea pigs of the Peru line were used. The animals were reared in elevated cages and fed with forage and concentrate, until reaching the slaughter age of 97 to 112 days. After slaughtering, the testicles and epididymis were removed, and the epididymis was separated of the testis. Measurements of the testicles were done, and sperm was collected from the epididymis by the retrograde flow washing technique. Semen smears were prepared for sperm measurements. The data were processed by GLM analysis of variance and the LSMeans procedure was used to compare the means (SAS v. 9.0). The morphometric parameters of the testes were different (p<0.05) between subpopulations. Opposite testes from the same genetic group were similar, while the ipsilateral ones between subpopulations showed statistical differences (p<0.05). Testicular size was directly related to body weight, and the gonadosomatic index of native guinea pigs was higher than that of improved ones (p<0.05). Spermatozoa were different (p<0.05) between genetic groups in acrosome and head length and in head length / width ratio. In conclusion, this study showed morphological differences in the testes and sperm between the two genetic groups of guinea pigs.El objetivo de esta investigación fue describir la morfometría de los testículos y espermatozoides de cuyes (Cavia porcellus) de dos grupos genéticos, nativos y mejorados, del sur de Ecuador. Se utilizaron 22 cuyes nativos y 20 mejorados de la línea Perú, los cuales fueron criados en jaulas elevadas y alimentados con forraje y concentrado, hasta alcanzar la edad de sacrificio de 97 a 112 días. Luego de faenados, se retiraron los testículos y epidídimos, y mediante disección se separó el epidídimo del testículo para tomar sus dimensiones, y recolectar los espermatozoides del epidídimo por la técnica de lavado por flujo retrógrado. Se prepararon frotis de semen para las mediciones de espermatozoides. Los datos se procesaron por análisis de varianza GLM y se utilizó el procedimiento LSMeans para comparar las medias (SAS V.9.0). Los parámetros morfométricos de los testículos fueron diferentes (p<0.05) entre subpoblaciones; testículos opuestos del mismo grupo genético fueron similares, mientras que los ipsilaterales entre subpoblaciones mostraron diferencias estadísticas (p<0.05). El tamaño testicular tuvo relación directa con el peso corporal, y el índice gonadosomático de los cuyes nativos fue mayor que el de los mejorados (p<0.05). Los espermatozoides fueron diferentes (p<0.05) entre grupos genéticos en la longitud del acrosoma y cabeza y en la relación longitud/ancho de cabeza. En conclusión, se encontraron diferencias morfológicas en los testículos y en los espermatozoides entre los dos grupos de cuyes

Centrifugación coloidal como método de selección espermática previo a la crioconservación con glicerol en caninos

Background: The ejaculate of the dog has three fractions, the first and third containing prostatic fluid that is harmful to cryopreservation, and the second rich in sperm. Obtaining only the second fraction of the ejaculate is complicated; therefore, colloidal centrifugation was evaluated as a sperm selection method, plus the addition of glycerol in three concentrations 4, 6 and 8 % as cryoprotector.  Methods: The study was conducted at the University of Cuenca-Ecuador, 72 seminal samples from 6 crossbreed dogs were evaluated. Each sample was divided into 2 aliquots, the first for Group 1 (conventional centrifugation) and the other Group 2 (colloidal centrifugation), once centrifuged each aliquot was sub-divided into three and 4, 6 and 8 % of glycerol were added. Three spermatic evaluations were carried out (initial, pre and post thawing).  Results: The sperm concentration after centrifugation was similar between the initial sample (MI) and Group 1 (P > 0.05); in Group 2 less sperm was observed (P < 0.05). When assessing the progressive individual motility (MIP) pre freezing, it was observed that the sperm of the Group 1 reduced 30 % its motility in relation to the sample MI and that of Group 2. Post thawing MIP within the groups with different concentrations of glycerol (4, 6, 8 %), which previously received centrifugation with Percoll (Group 2) presented statistical difference (P < 0.05). However, the HOS test gave similar percentages.  Conclusions: It is concluded that colloidal centrifugation, prior to the freezing process, is a technique that allows greater selection and sperm purification.Antecedentes: El eyaculado del perro presenta tres fracciones, la primera y tercera que contienen líquido prostático que es perjudicial para la criopreservación, y la segunda rica en espermatozoides. Obtener únicamente la segunda fracción del eyaculado es complicado; por lo tanto, se evaluó la centrifugación coloidal como método de selección espermática, más la adición de glicerol en tres concentraciones 4; 6 y 8 % como crio protector.  Métodos: El estudio fue realizado en la Universidad de Cuenca-Ecuador, se valoraron 72 muestras seminales procedentes de 6 perros mestizos. Cada muestra fue dividida en 2 alícuotas, la primera para el Grupo 1 (centrifugación convencional) y la otra Grupo 2 (centrifugación coloidal). Una vez centrifugadas cada alícuota fue sub-dividida en tres y se les adicionó 4; 6 y 8 % de glicerol. Se realizaron 3 evaluaciones espermáticas (inicial, pre y post descongelación).  Resultados: La concentración espermática luego de la centrifugación fue similar entre la muestra inicial (MI) y Grupo 1 (P > 0,05); en Grupo 2 se observó menos espermatozoides (P < 0,05). Al valorar la motilidad individual progresiva (MIP) pre congelación, se observó que los espermatozoides del Grupo 1 redujeron un 30 % su motilidad en relación a la muestra MI y la de Grupo 2. La MIP post descongelación dentro de los grupos con diferentes concentraciones de glicerol (4; 6 y 8 %), que recibieron previamente centrifugación con Percoll (Grupo 2) presentaron diferencia estadística (P < 0,05). Sin embargo, la prueba de HOS proporcionó porcentajes similares.  Conclusiones: Se concluye que la centrifugación coloidal, previa al proceso de congelación es una técnica que permite mayor selección y purificación espermática

Extirpación de las espículas del pene de cuy (Cavia porcellus) y su efecto sobre la ganancia de peso y agresividad

La investigación fue realizada en la Granja de Irquis propiedad de la Universidad de Cuenca ubicada en la parroquia Victoria del Portete, cantón Cuenca, provincia del Azuay, se estudió el efecto de la extirpación de las espículas peneanas sobre la ganancia de peso y la agresividad, expresada según el daño a la canal, con animales al inicio de la etapa de recría y/o engorde. Se conformaron tres tratamientos: animales enteros sin castración como testigo (T1), animales con extirpación de las espículas del glande (T2) y animales castrados químicamente con 0,5 ml de alcohol yodado al 2 % inyectado directamente en cada testículo (T3). Se utilizaron 90 animales, distribuidos en un diseño en bloques al azar con seis bloques y cinco réplicas. La alimentación estuvo constituida por una mezcla forrajera siendo presupuestada entre 33 a 35 % de peso vivo en materia verde y un concentrado comercial con consumo ad libitum. Se realizó un análisis de covarianza (ANACOVA) con el peso inicial como covariable, el peso final fue influenciado significativamente por el tratamiento, se utilizó la prueba de Tukey dando como resultado que T2 alcanzó el mayor peso final seguido por T1 comportándose significativamente diferentes a T3 (P < 0,05). Respecto a la agresividad expresada en daño a la canal no se encontraron diferencias significativas según Chi cuadrado (P > 0,05).AbstractThis research took place on the Irquis Farm, University of Cuenca, Victoria del Portete parish, Cuenca canton, province of Anzuay, Ecuador. This research studied the effects of penile spicule extirpation on weight gain and aggressiveness, according to damage caused to the carcass at the beginning of growing/fattening. The study consisted of three treatments: whole animals without castration, used as controls (T1); animals with extirpation of the gland´s spicules (T2); and chemically castrated animals, using 0.5 ml of 2 % alcohol with iodine, directly injected in each testicle (T3). A total of 90 animals were included, following a randomized block design with six treatments and five replicas. The diet consisted of forage mixture of 33-35 % dry matter, and a commercial feed supplement administered ad libitum. A covariance analysis (ANACOVA) was made, using the initial weight as co-variable. The final weight was significantly influenced by the treatment; the Tukey test resulted in greater final weight in T2, followed by T1. Their behavior was significantly different from T3 (P < 0.05). In relation to aggressiveness, expressed in carcass damage, no significant differences were observed, according to Chi square (P > 0.05)