ABSTRACT
This study aimed to identify inbreeding coefficient (F) estimators useful for improvement programs in a small Holstein population through the evaluation of different methodologies in the Mexican Holstein population. F was estimated as follows: (a) from pedigree information (Fped); (b) through runs of homozygosity (Froh); (c) from the number of observed and expected homozygotic SNP in the individuals (Fgeno); (d) through the genomic relationship matrix (Fmg). The study included information from 4277 animals with pedigree records and 100,806 SNP. The average and standard deviation values of F were 3.11 ± 2.30 for Fped, -0.02 ± 3.55 for Fgeno, 2.77 ± 0.71 for Froh and 3.03 ± 3.05 for Fmg. The correlations between coefficients varied from 0.30 between Fped and Froh, to 0.96 between Fgeno and Fmg. Differences in the level of inbreeding among the parent's country of origin were found regardless of the method used. The correlations among genomic inbreeding coefficients were high; however, they were low with Fped, so further research on this topic is required.
ABSTRACT
The objective of the present study was to estímate growth curve parameters of length and weight in whitefish Chirostoma estor (EE), blacknose silverside Chirostoma promelas (PP) and their reciprocal hybrids (EP and PE) up to 300 days of age from a complete diallel cross under culture conditions in Morelia, Michoacan, Mexico. The length was measured monthly from hatching, while the weight was measured monthly from 120 days of age. The total number of each observation (samples) was analyzed for length 1006 (26), 771 (22), 513 (22) and 421 (21) for groups EP, PE, PP and EE, respectively. Total number of observations (samples) was analyzed for weight 630 (16), 521 (14), 263 (13) and 256 (13) for groups EP, PE, PP and EE, respectively. The growth curves for weight and length were estimated using nonlinear regression models. The group EE reached an estimated weight of 7.89 g at 300 days of age, 65% higher than the PP (4.78 g) and 57 % higher than the average of their hybrids (P < 0.01); EE had a length of 9.31 cm (14%) larger than PP (7.97 cm) and 13% larger than the average of their hybrids (P < 0.01). The four groups showed a positive allometric growth with values of 3.20 to 3.3 (P < 0.05). The results of this study are the first comparative estimates of growth characteristics up to 300 days of age for these species and their hybrids in captivity.
El objetivo del presente estudio fue estimar parámetros de las curvas de crecimiento del peso y la longitud en el pez blanco Chirostoma estor (EE), el pez blanco pico negro Chirostoma promelas (PP) y de sus híbridos recíprocos (EP y PE) hasta los 300 días de edad a partir de un cruzamiento dialélico completo bajo condiciones de cultivo en Morelia, Michoacán, México. La longitud se midió mensualmente desde la eclosión, mientras que el peso se midió mensualmente a partir de los 120 días. Los números totales de observaciones (muestras) analizadas para longitud fueron 1006 (26), 771 (22), 513 (22) y 421 (21) para los grupos EP, PE, PP y EE, respectivamente. Los números totales de observaciones (muestras) analizadas para peso fueron 630 (16), 521 (14), 263 (13) y 256 (13) para los grupos EP, PE, PP y EE, respectivamente. Las curvas de crecimiento para peso y longitud se estimaron con modelos de regresión no lineal. El grupo EE alcanzó un peso estimado de 7.89 g a los 300 días de edad, 65% mayor que el de PP (4.78 g) y 57% mayor que el promedio de los híbridos (P < 0.01); EE tuvo una longitud de 9.31 cm (14%) mayor que PP (7.97 cm) y 13% mayor que la del promedio de los híbridos (P < 0.01). Los cuatro grupos, mostraron un crecimiento de tipo alométrico positivo con valores de 3.2 a 3.3 (P < 0.05). Los resultados de este estudio son las primeras estimaciones comparativas de las características de crecimiento hasta los 300 días de edad para estas especies y sus híbridos en cautiverio.