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Morales-Ueno K.,Research Center Cientifica Educacion Superior Of Ensenada | Montaldo H.H.,National Autonomous University of Mexico | Ortega A.M.,Maricultura del Pacifico SA de CV | Paniagua-Chavez C.G.,Research Center Cientifica Educacion Superior Of Ensenada | Castillo-Juarez H.,Metropolitan Autonomous University
Aquaculture Research | Year: 2013

Some shrimp hatcheries use artificial insemination (AI) to improve the male to female ratio in their breeding populations. We describe a sperm extender solution, which allows the short-term storage of diluted sperm in Litopenaeus vannamei, and its use in an artificial insemination process. We also evaluate its fertilization capacity. An AI experiment was designed using two, one, or half spermatophore segments. We tested four treatments involving three different male:female ratios: Natural mating (1:1), Regular and Regular diluted (1:2) and Half diluted (1:4). Data analysis revealed that the number of nauplii produced per mating was affected by treatment, with Regular (158 420) performing better than Half diluted (112 864) (P < 0.05), but with no differences between the latter and Regular diluted (130 340) (P > 0.05). A binomial variable named female success (FS) was defined as successful when the number of nauplii obtained per mate was ≥25 000. Analysis showed differences for FS across treatments (P < 0.001), but not between Regular (79.2%), the hatchery conventional AI technique and Half diluted (60.4%), maybe due to sample size. Since the number of nauplii per mate is crucial to consider AI successful, it is necessary to improve this AI technique before it can be used in the shrimp industry. © 2012 John Wiley & Sons Ltd. Source


Caballero-Zamora A.,Metropolitan Autonomous University | Montaldo H.H.,National Autonomous University of Mexico | Campos-Montes G.R.,Metropolitan Autonomous University | Campos-Montes G.R.,Maricultura del Pacifico SA de CV | And 3 more authors.
Aquaculture | Year: 2015

White Spot Syndrome Virus (WSSV) is a disease that causes large economic losses in the shrimp industry. Genetic improvement is a strategy for controlling some diseases in aquaculture. Genetic parameter estimates for body weight and survival in the presence of WSSV have been obtained from laboratory challenge experimental designs, but there are no studies in the presence of a WSSV natural outbreak. The aims of this study were (1) to estimate genetic parameters for body weight at 19. weeks of age and survival from 10 to 19. weeks of age in the Pacific white shrimp ( Penaeus (Litopenaeus) vannamei) in a pond affected by a natural outbreak of WSSV, and (2) to compare these estimates with those obtained from two ponds where no WSSV was present. The estimate of the heritability for body weight was smaller in the presence of WSSV (0.09 to 0.11) than in ponds with no WSSV (0.15 to 0.33). An increase in body weight residual variance was observed in the pond affected by WSSV. The estimate of the heritability of survival for the pond affected by WSSV (0.06. ±. 0.03) was larger than that estimated in the unaffected ones (0.00 to 0.02), suggesting a minor change in the additive genetic expression of this trait. Heritability estimates for body weight and survival are the first ones obtained in a population affected by a WSSV natural outbreak using pedigreed information. Results suggest that selection response for survival at harvesting in the presence of WSSV would be very small, and that selection response for body weight in the same condition would be smaller than in the absence of WSSV. Studies regarding the implications of including these and other important traits in shrimp breeding programs in the presence of WSSV are necessary. © 2014 Elsevier B.V. Source


Vela Avitua S.,National Autonomous University of Mexico | Montaldo H.H.,National Autonomous University of Mexico | Marquez Valdelamar L.,National Autonomous University of Mexico | Campos Montes G.R.,Metropolitan Autonomous University | And 2 more authors.
Electronic Journal of Biotechnology | Year: 2013

Background: The objective of this study was to estimate the decline of genetic variability and the changes in effective population size in three shrimp populations. One was a wild population collected at several points in the Mexican Pacific Ocean. The other two populations were different generations (7 and 9) from a captive population selected for growth and survival. Microsatellite markers and pedigree were both used to assess genetic variability and effective population size. Results: Using 26 loci, both captive populations showed a decline in the expected heterozygosity (20%) and allelic diversity indices (48 to 91%) compared to the wild population (P < 0.05). The studied captive populations did not differ significantly from each other regarding their expected heterozygosity or allelic diversity indices (P > 0.05). Effective population size estimates based on microsatellites declined from 48.2 to 64.0% in cultured populations (P < 0.05) compared to the wild population. Conclusions: An important decline of genetic variability in the cultured selected population due to domestication, and evidence of a further smaller decline in effective population size across generations in the selected population were observed when analyzing pedigree (41%) and microsatellite data (37%). Pedigree keeping is required to prevent the decline of effective population size and maintain genetic variability in shrimp breeding programs, while microsatellites are useful to assess effective population size changes at the population level. Source


De Los Rios-Perez L.,National Autonomous University of Mexico | Campos-Montes G.R.,Metropolitan Autonomous University | Martinez-Ortega A.,Maricultura del Pacifico SA de CV | Castillo-Juarez H.,Metropolitan Autonomous University | Montaldo H.H.,National Autonomous University of Mexico
Journal of the World Aquaculture Society | Year: 2015

The objective of this study was to investigate the effect of inbreeding on body weight (BW) at harvest size (130d of age) and grow-out survival rate (SR) (65-130 d of age) in a nucleus breeding population of Penaeus (Litopenaeus) vannamei. An experiment was designed to generate inbred families the product of sibling matings, as well as groups of families with different inbreeding coefficients in three successive generations. The families came from a broodstock line selected for growth and survival. Inbreeding coefficients varied between 0 and 60.4%. A total of 16,361 shrimp from 320 families were produced. Data were analyzed using mixed linear model methodology and restricted maximum likelihood methods. Estimated change on BW per 10% increase on the inbreeding coefficient was -2.19±0.41% (P <0.001) relative to the mean of non-inbred shrimp predicted from the model (19.63g). Regression coefficient for grow-out SR on inbreeding was not significant. Estimated change in SR per 10% increase on the inbreeding coefficient was -0.009±0.006% (P = 0.108) relative to the mean of non-inbred shrimp predicted from the model (81.72%). It is important to control inbreeding level in breeding programs. © World Aquaculture Society 2015. Source

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