Roberto Neira

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Verified

Roberto verified their affiliation via an institutional email.

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• PhD
• Professor (Full) at University of Chile

The parr-smolt transformation in salmonids involves a critical period characterized by systemic changes associated with the fish's immune response. In this context, as a dietary ingredient in functional diets, microalgae offer an alternative due to their nutritional and bioactive compounds that could strengthen the immune status. This study evaluat...

Coho salmon (Oncorhynchus kisutch) are a culturally and economically important species that return from multiyear ocean migrations to spawn in rivers that flow to the Northern Pacific Ocean. Southern stocks of coho salmon in Canada and the United States have significantly declined over the past quarter century, and unfortunately, conservation effor...

Coho salmon ( Oncorhynchus kisutch ) are a culturally and economically important species that return from multiyear ocean migrations to spawn in rivers that flow to the Northern Pacific Ocean. Southern stocks of coho salmon have significantly declined over the past quarter century, and unfortunately, conservation efforts have not reversed this tren...

Domestication of Atlantic salmon started approximately 40 years ago, using artificial selection through genetic improvement programs. Selection is likely to have imposed distinctive signatures on the salmon genome, which are often characterized by high genetic differentiation across population and/or reduction in genetic diversity in regions associ...

Piscirickettsiosis caused by the intracellular bacterium Piscirickettsia salmonis and caligidosis produced by the ectoparasite Caligus rogercresseyi, are important diseases which generate great economic losses in salmonid farming in Chile. Selective breeding for pathogen resistance has been proposed as an alternative tool for the control of disease...

Genetic improvement is key to the development of a more efficient aquaculture industry. By 2010, there were 104 breeding programmes for aquaculture species in the world, most of them for fish species. Usually, the breeding goals include traits such as growth rate, disease resistance, maturation and carcass quality. Resistance to specific pathogens...

Domestication of Atlantic salmon started approximately forty years ago, using both artificial and natural selection strategies. Such selection methods are likely to have imposed distinctive selection signatures on the salmon genome. Therefore, identifying differences in selection signatures may give insights into the mechanism of selection and cand...

Selective breeding and genetic improvement have left detectable signatures on the genomes of domestic species. The elucidation of such signatures is fundamental for detecting genomic regions of biological relevance to domestication and improving management practices. In aquaculture, domestication was carried out independently in different locations...

From a physiological-behavioral perspective, it has been shown that fish with a higher density of black eumelanin spots are more dominant, less sensitive to stress, have higher feed intake, better feed efficiency and therefore are larger in size. Thus, we hypothesized that genetic (co)variation between skin pigmentation patterns and growth exists a...

Infectious pancreatic necrosis (IPN) is one of the most prevalent and economically important diseases in rainbow trout aquaculture (Oncorhynchus mykiss). Vaccines as a conventional control measure have shown inconsistent results under production conditions. Genetic improvement for resistance to IPN represents an alternative for the prevention of di...

Chilean coho salmon (Oncorhynchus kisutch) represents about 90% of the worldwide production. From a commercial perspective rapid growth to market weights and product quality are important aspects of profitability. The objective of this study was to determine genetic parameters, genetic trends and correlated response of flesh color (FC) after eight...

A considerable number of single nucleotide polymorphisms (SNPs) are required to elucidate genotype-phenotype associations and determine the molecular basis of important traits. In this work, we carried out de novo SNP discovery accounting for both genome duplication and genetic variation from American and European salmon populations. 9,736,473 non-...

This study examined four commercial lines of Nile tilapia (Oerochromis niloticus) ultimately to implement a breeding program to produce clean fillets from an all-male fish population that is grown to 1 kg. Contemporary progenies were produced to perform a complete 4 × 4 diallel cross. Two experimental populations were studied: (1) a set of hormonal...

The objectives of this study were to measure gene expression in zebrafish and then identify SNP to be used as potential markers in a growth association study. We developed an approach where muscle samples collected from low- and high-growth fish were analyzed using RNA-Sequencing (RNA-seq), and SNP were chosen from the genes that were differentiall...

Selection signatures are genomic regions harboring DNA sequences functionally involved in the genetic variation of traits subject to selection. Selection signatures have been intensively studied in recent years because of their relevance to evolutionary biology and their potential association with genes that control phenotypes of interest in wild a...

The dissection of the molecular basis of relevant traits in farmed Atlantic salmon and the implementation of genomic selection schemes require a considerable number of single nucleotide polymorphisms (SNPs). In this study we performed a de novo SNP discovery and developed an Affymetrix Axiom® myDesign Custom Array, taking genome duplication and acr...

Abstract Text: The evolution of Coho salmon breeding programs, breeding objectives, genetic architecture, genetic response and trends, genetics of disease resistance and future implementation of genomic selection in Coho breeding are analyzed. The genetic gain for growth, after 7-8 generations, with a generation interval of 2 years, has been 10-13%...

Infectious and parasitic diseases are recognized worldwide as primary causes of economic losses in salmon production. Piscirickettsia salmonis and Caligus rogercresseyi are the main diseases affecting Chilean salmon aquaculture. In this study, we used data from experimental challenges against P. salmonis and C. rogercresseyi in full- and half-sibs...

Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with r...

Piscirickettsiosis (Piscirickettsia salmonis) is one of the diseases that cause large economic losses in Chilean salmon industry. Genetic improvement of disease resistance represents one strategy for controlling infectious diseases in farmed fish. However, knowledge of whether genetic variation exists for piscirickettsiosis resistance is needed in...

Abstract The main objective of this study was to examine the effects of a plant protein- vs. fishmeal-based diet on growth response in a population of 24 families, as well as expression of growth-related genes in the muscle of adult zebrafish (Danio rerio). Each family was split to create two fish populations with similar genetic backgrounds, and t...

Over the last decade, the native parasite which has worst affected salmonids reared in Chile (Atlantic salmon and Rainbow trout) is Caligus rogercresseyi (González & Carvajal 1994; González, Carvajal & Medina 1995; Boxshall & Bravo 2000; Rozas & Asencio 2007). The financial costs associ-ated with treating Caligus have been estimated at US$0.30 kg À...

A total of 1511 Atlantic salmon smolts representing 75 full-sib and 40 half-sib families from the Antares S.A. breeding program were challenged with Caligus rogercresseyi in order to assess the quantitative genetic components of resistance to infection by this parasite. After three weeks of acclimatization in the experimental hatchery conditions, f...

Zebrafish (Danio rerio) is a common research model in fish studies of toxicology, developmental biology, neurobiology and molecular genetics; it has been proposed as a possible model organism for nutrition and growth studies in fish. The advantages of working with zebrafish in these areas are their small size, short generation time (12–14weeks) and...

Caligus rogercresseyi has been for many years one of the most important health problem during the sea water phase of farmed salmon in Chile. Fish resistant to Caligus has emerged as a priority for the industry; however, there is not an efficient methodology to identify the animals resistant to Caligus. The overall objetive of this study was to deve...

Table S1 - Ranking of breeding values estimaed with different models for the Odd population. Sires and dams excluded from the group selected by the simple model per generation, 30 best sires and 100 best dams, in each of the models are marked in bold. This table shows the ranking based on breeding values obtained for the different models in the odd...

In this study, we used different animal models to estimate genetic and environmental variance components on harvest weight in two populations of Oncorhynchus kisutch, forming two classes i.e. odd- and even-year spawners. The models used were: additive, with and without inbreeding as a covariable (A + F and A respectively); additive plus common envi...

In salmonids, spawning date is an important productive and life-history trait determining the time of fertilization, date of progeny emergence, and even the probability of survival and the growth rate of the small fry. Recent evidences support a polygenic basis with several Quantitative Trait Loci (QTL) affecting the phenotypic expression of this t...

In the last decade, advances in molecular methods have permitted the detection of major genes or chromosomal regions (quantitative trait loci, QTLs) that account for an important fraction of the phenotypic variance of productive traits in many domestic animals, principally mammals. These discoveries have only been possible due to the development of...

This book on methodologies for risk assessment and management of transgenic fish is written by 44 authors from 19 countries. It is comprised of 10 chapters giving emphasis on developing countries which have transgenic fish research programmes or aquaculture systems that may use transgenic fish in the future. This book is aimed at helping government...

Phenotypic records of within-year spawning date in two cultivated populations of coho salmon, named as even (n=2272) and odd (n=1347) year classes are analyzed. Both populations were selected for harvest weight and early spawning for four generations, using independent culling levels. Hat-vest weight was selected using breeding values obtained from...

In this study the genetic response to selection and the effects of inbreeding on harvest weight in two populations (which spawned as even and odd years classes) of Coho salmon are described. Artificial selection was performed using the best linear unbiased prediction (BLUP) of breeding values obtained from an animal model. Both populations were als...

We evaluated the effects of inbreeding on traits related to territorial dominance and tested whether the magnitude of inbreeding depression (ID) was modified by social environment in Coho salmon. Evaluation of behaviour in paired contests between juvenile salmon with different inbreeding (low, LI=9.5%; medium, MI=29.6%), did not show significant di...

Flesh colour in salmonids is a very important commercial trait that shows additive genetic variance with significant environmental influence. Selective breeding for this trait is difficult, since phenotypic evaluation requires individuals to be sacrificed for scoring. We have identified a RAPD marker that co-segregates with colour traits scored as...

Biotechnology: "Any technique that uses living organisms to make or modify a product, to improve plants or animals or to develop microorganisms for specific uses". (US Congress Office of Technology Assessment) A broad definition of biotechnology as the previous one, demonstrates that this is an old and extensively used technology. We can distinguis...

Phenotypic and genetic parameter estimates of carcass quality traits were obtained from two pedigreed populations, termed even and odd, of a Coho salmon breeding program. Carcass quality data from 3444 fish (1802 male and 1642 female), harvested at 21 months of age, were analyzed. In both populations, significant sex effects were found for body wei...

Levels of inbreeding and inbreeding depression were studied in two populations of Coho salmon (Oncorhynchus kisutch) in Chile. The two populations, termed even year, and odd year were artificially selected by weight at harvest over four generations, using the best linear unbiased prediction (BLUP) of breeding values. Also, general linear models (GL...

Based on 8 years of data on 891 daughters from 190 sires and 398 dams, females produced an average (standard deviation) of 4251 (957) green eggs with a total weight of about 680 (191) g; the females produced 3226 (1255) eyed eggs, average egg weight was 180 (27) mg, and the average day of spawning was 137.5 (9.8) days measured from December 31. Ave...

Levels of inbreeding and inbreeding depression were studied in two populations of Coho salmon (Oncorhynchus kisutch) in Chile. The two populations, termed even year, and odd year were artificially selected by weight at harvest over four generations, using the best linear unbiased prediction (BLUP) of breeding values. Also, general linear models (GL...

Chilean salmon culture is based on a high degree of artificial selection, which has had the tendency to increase the inbreeding (F). Three types of nonrandom mating were evaluated to control the inbreeding in two best linear unbiased prediction selected coho salmon (Oncorhynchus kisutch) populations (even and odd). These included compensatory matin...

The purpose of the study was to assess the impact of various model structures on REML estimates of variance components using data on alevin weight from two replicate populations from the Genetic Improvement Program for Coho salmon (Chile). Data consisted of 130 d alevin weight from a dams-nested-within-sires mating design over two consecutive gener...

The gametogenesis of a 2-year-old coho salmon broodstock population cultured in a fish farm in southern Chile was studied. Gonadosomatic index (GSI), microscopic gonadal traits, and serum levels of estradiol-17β(E2), testosterone, and 17α,20β-dihydroxy-4-pregnene-3-one (17,20P) in both sexes were recorded beginning 9 months before spawning in bimon...

Data on reproductive traits from 1,229 mature 2-year-old female coho salmon Oncorhynchus kisutch were collected during 2 years at four salmon farms in southern Chile. Spawning periods were similar in 1993 and 1994 (39 and 41 d, respectively). The spawning period of May–June, corresponded to the full reproductive period in the northern hemisphere. T...

Reproductive variables of 986 female rainbow trout (Oncorhynchus mykiss) spawned during 1990 in a hatchery in central Chile were evaluated. Data were recorded on individual females. Fish were spawned over a 9-month period, from March to November. The data indicated the coexistence of different strains of fish with different spawning times. There wa...

A partir de una distinción respecto a lo que se consideran biotecnologías clásicas, se revisa en este artículo, su aplicación a la reproducción de especies cultivadas. Se establecen los desafíos que implica el control de la maduración reproductiva, el control de la fertilidad, el control del sexo genético y de la proporción de sexos en las progenie...

SPEC. COLL. HAS ARCHIVAL COPY; MICRO. ROOM HAS MICROFICHE COPY (2 SHEETS). Thesis (Ph.D.)--U. of Calif., Davis. Typescript. Degree granted in Genetics.