In Vivo Ultrasound Prediction of the Fillet Volume in Senegalese Sole (Solea senegalensis).

Senegalese sole (Solea senegalensis) has been considered a promising new flatfish species for Mediterranean marine fish farming. Accurate prediction of fillet traits in live animals may allow for more efficient control of muscle deposition in fish. In this sense, this study was undertaken to develop a non-invasive method to predict in vivo fish fillet volume and yield using real-time ultrasonography (RTU). The trial was conducted with 44 market weight Senegalese sole (298.54 ± 87.30 g). Fish were scanned with an Aloka SSD 500V with a 7.5 MHz probe. Ten RTU cross-sectional images were taken from the operculum to the caudal fin at regular intervals. These images were analyzed using Fiji software. These data were then used to estimate the partial volumes of the fillet. Actual fillet volume was determined using Archimedes' principle. Simple and stepwise multiple regression analyses were then used to develop prediction models of fillet volume and yield. The most cranial RTU sections of the fish fillet were the best single predictors of both fillet volume and fillet yield and were the ones included in the best stepwise models. The best RTU slice area explained 82% of the variation observed in fillet volume, but the other RTU slice areas used as predictors of fillet volume showed poor to moderate accuracy (0.035 ≤ R2 ≤ 0.615). Single RTU partial volumes showed poor to very high accuracy (0.395 ≤ R2 ≤ 0.970) as predictors of fillet volume. The best stepwise model based on the RTU slice areas included three independent variables and explained 88.3% of the observed variation. The best stepwise models based on RTU partial volumes (single volumes and/or combinations of single volumes) explained about 97% of the variation observed in fillet volume. Two RTU volume traits, V1-5 + V6-9, and V1+()+9, showed to be practically direct predictors of the actual fillet volume, explaining, respectively, 97% and 96% of the variation observed in the actual fillet volume. The fillet yields show lower correlations with slice areas (r between 0.044 and 0.601) than with volumes (r between 0.288 and 0.637). While further studies are clearly necessary to better understand the potential of RTU for the estimation of fillet yield in fish in general and Senegalese sole in particular, the present results showed that RTU traits can be very good predictors of Senegalese sole's fillet volume, either used in regression models or as direct predictors.

Does Production of Clarias gariepinus × Heterobranchus longifilis Hybrids Influence Quality Attributes of Fillets?

The increase in fish and seafood consumption observed in recent years is a consequence of the growing consumers' awareness of proper nutrition. One of the possibilities to provide fish-friendly, qualitatively attractive (both in terms of nutrition and sensory quality) raw fish materials is the production of hybrids, which would improve production rates without compromising their meat quality. This study compares the carcass and fillet yields of Clarias gariepinus (C) and heteroclarias C. gariepinus × Heterobranchus longifilis (H), and the nutritional (chemical composition, fat quality) and culinary quality (structure, texture, color, cooking loss, sensory characteristics) of their meat. Significantly (p ≤ 0.05) higher carcass and fillet yield was shown for H, whose fillets had comparable sensory quality and proximal composition to C. The meat of H can be an attractive raw material for more demanding groups of consumers-for children and adolescents (due to the less intense fish tastiness), as well as for older people who have problems with chewing and digesting food (due to lower sensory chewiness and perception of connective tissue).

First Evidence of Realized Selection Response on Fillet Yield in Rainbow Trout Oncorhynchus mykiss, Using Sib Selection or Based on Correlated Ultrasound Measurements.

Fillet yield, the proportion of edible fillet relative to body weight, is a major trait to improve in fish sold processed, as it has a direct impact on profitability and can simultaneously decrease the environmental impact of producing a given amount of fillet. However, it is difficult to improve by selective breeding, because it cannot be measured on live breeding candidates, its phenotypic variation is low, and, as a ratio, it is not normally distributed and a same change in fillet yield can be the result of different changes in fillet weight and body weight. Residual headless gutted carcass weight (rHGCW) is heritable and highly genetically correlated to Fillet% in rainbow trout, and can be predicted by the ratio of abdominal wall thickness to depth of the peritoneal cavity (E8/E23), measured on live fish by ultrasound tomography. We selected broodstock based on rHGCW, measured on sibs of the selection candidates, on ultrasound measurements (E8/E23) measured on the selection candidates, or a combination of both. Seven broodstock groups were selected: fish with 15% highest (rHGCW+) or lowest (rHGCW-) EBV for rHGCW, with 15% highest (E8/E23+) or lowest (E8/E23-) EBV for E8/E23, with both rHGCW+ and E8/E23+ (Both+) or rHGCW- and E8/E23- (Both-), or with close to zero EBVs for both traits (Mid). Seven corresponding groups of offspring were produced and reared communally. At harvest size (1.5 kg mean weight), 1,561 trout were slaughtered, measured for the traits of interest, and pedigreed with DNA fingerprinting. Offspring from groups Both+, rHGCW+ and E8/E23+ had a higher EBV for rHGCW than the control group, while down-selected groups had a lower EBV. Looking at the phenotypic mean for Fillet% (correlated response), up-selected fish had more fillet than down-selected fish. The highest difference was between Both+ (69.36%) and Both- (68.20%), a 1.16% units difference in fillet percentage. The change in Fillet% was explained by an opposite change in Viscera%, while Head% remained stable. Selection using sib information on rHGCW was on average more efficient than selection using the candidates' own E8/E23 phenotypes, and downward selection (decreasing Fillet%) was more efficient than upward selection.

Genome-Wide Association Analysis With a 50K Transcribed Gene SNP-Chip Identifies QTL Affecting Muscle Yield in Rainbow Trout.

Detection of coding/functional SNPs that change the biological function of a gene may lead to identification of putative causative alleles within QTL regions and discovery of genetic markers with large effects on phenotypes. This study has two-fold objectives, first to develop, and validate a 50K transcribed gene SNP-chip using RNA-Seq data. To achieve this objective, two bioinformatics pipelines, GATK and SAMtools, were used to identify ~21K transcribed SNPs with allelic imbalances associated with important aquaculture production traits including body weight, muscle yield, muscle fat content, shear force, and whiteness in addition to resistance/susceptibility to bacterial cold-water disease (BCWD). SNPs ere identified from pooled RNA-Seq data collected from ~620 fish, representing 98 families from growth- and 54 families from BCWD-selected lines with divergent phenotypes. In addition, ~29K transcribed SNPs without allelic-imbalances were strategically added to build a 50K Affymetrix SNP-chip. SNPs selected included two SNPs per gene from 14K genes and ~5K non-synonymous SNPs. The SNP-chip was used to genotype 1728 fish. The average SNP calling-rate for samples passing quality control (QC; 1,641 fish) was ≥ 98.5%. The second objective of this study was to test the feasibility of using the new SNP-chip in GWA (Genome-wide association) analysis to identify QTL explaining muscle yield variance. GWA study on 878 fish (representing 197 families from 2 consecutive generations) with muscle yield phenotypes and genotyped for 35K polymorphic markers (passing QC) identified several QTL regions explaining together up to 28.40% of the additive genetic variance for muscle yield in this rainbow trout population. The most significant QTLs were on chromosomes 14 and 16 with 12.71 and 10.49% of the genetic variance, respectively. Many of the annotated genes in the QTL regions were previously reported as important regulators of muscle development and cell signaling. No major QTLs were identified in a previous GWA study using a 57K genomic SNP chip on the same fish population. These results indicate improved detection power of the transcribed gene SNP-chip in the target trait and population, allowing identification of large-effect QTLs for important traits in rainbow trout.

Genetic parameters for growth performance, fillet traits, and fat percentage of male Nile tilapia (Oreochromis niloticus).

Improvement of fillet traits and flesh quality attributes are of great interest in farmed tilapia and other aquaculture species. The main objective of this study was to estimate genetic parameters for fillet traits (fillet weight and fillet yield) and the fat content of fillets from 1136 males combined with 2585 data records on growth traits (body weight at 290 days, weight at slaughter, and daily weight gain) of 1485 males and 1100 females from a third generation of the Aquaamerica tilapia strain. Different models were tested for each trait, and the best models were used to estimate genetic parameters for the fat content, fillet, and growth traits. Genetic and phenotypic correlations were estimated using two-trait animal models. The heritability estimates were moderate for the fat content of fillets and fillet yield (0.2-0.32) and slightly higher for body weight at slaughter (0.41). The genetic correlation between fillet yield and fat was significant (0.6), but the genetic correlations were not significant between body weight and fillet yield, body weight and fat content, daily weight gain and fillet yield, and daily weight gain and fat content (- 0.032, - 0.1, - 0.09, and - 0.4, respectively). Based on the genetic correlation estimates, it is unlikely that changes in fillet yield and fat content will occur when using growth performance as a selection criterion, but indirect changes may be expected in fat content if selecting for higher fillet yield.

Effects of steroid treatment on growth, nutrient partitioning, and expression of genes related to growth and nutrient metabolism in adult triploid rainbow trout (Oncorhynchus mykiss).

The contribution of sex steroids to nutrient partitioning and energy balance during gonad development was studied in rainbow trout. Specifically, 19-mo old triploid (3N) female rainbow trout were fed treatment diets supplemented with estradiol-17ß (E2), testosterone (T), or dihydrotestosterone at 30-mg steroid/kg diet for a 1-mo period. Growth performance, nutrient partitioning, and expression of genes central to growth and nutrient metabolism were compared with 3N and age-matched diploid (2N) female fish consuming a control diet not supplemented with steroids. Only 2 N fish exhibited active gonad development, with gonad weights increasing from 3.7% to 5.5% of body weight throughout the study, whereas gonad weights in 3N fish remained at 0.03%. Triploid fish consuming dihydrotestosterone exhibited faster specific growth rates than 3N-controls (P < 0.05). Consumption of E2 in 3N fish reduced fillet growth and caused lower fillet yield compared with all other treatment groups (P < 0.05). In contrast, viscera fat gain was not affected by steroid consumption (P > 0.05). Gene transcripts associated with physiological pathways were identified in maturing 2N and E2-treated 3N fish that differed in abundance from 3N-control fish (P < 0.05). In liver these mechanisms included the growth hormone/insulin-like growth factor (IGF) axis (igf1, igf2), IGF binding proteins (igfbp1b1, igfbp2b1, igfbp5b1, igfbp6b1), and genes associated with lipid binding and transport (fabp3, fabp4, lpl, cd36), fatty acid oxidation (cpt1a), and the pparg transcription factor. In muscle, these mechanisms included reductions in myogenic gene expression (fst, myog) and the proteolysis-related gene, cathepsin-L, suggesting an E2-induced reduction in the capacity for muscle growth. These findings suggest that increased E2 signaling in the sexually maturing female rainbow trout alters physiological pathways in liver, particularly those related to IGF signaling and lipid metabolism, to partition nutrients away from muscle growth toward support of maturation-related processes. In contrast, the mobilization of viscera lipid stores appear to be mediated less by E2 and more by energy demands associated with gonad development. These findings improve the understanding of how steroids regulate nutrient metabolism to meet the high energy demands associated with gonad development during sexual maturation.

Genome-Wide Association Study for Identifying Loci that Affect Fillet Yield, Carcass, and Body Weight Traits in Rainbow Trout (Oncorhynchus mykiss).

Fillet yield (FY, %) is an economically-important trait in rainbow trout aquaculture that affects production efficiency. Despite that, FY has received little attention in breeding programs because it is difficult to measure on a large number of fish and cannot be directly measured on breeding candidates. The recent development of a high-density SNP array for rainbow trout has provided the needed tool for studying the underlying genetic architecture of this trait. A genome-wide association study (GWAS) was conducted for FY, body weight at 10 (BW10) and 13 (BW13) months post-hatching, head-off carcass weight (CAR), and fillet weight (FW) in a pedigreed rainbow trout population selectively bred for improved growth performance. The GWAS analysis was performed using the weighted single-step GBLUP method (wssGWAS). Phenotypic records of 1447 fish (1.5 kg at harvest) from 299 full-sib families in three successive generations, of which 875 fish from 196 full-sib families were genotyped, were used in the GWAS analysis. A total of 38,107 polymorphic SNPs were analyzed in a univariate model with hatch year and harvest group as fixed effects, harvest weight as a continuous covariate, and animal and common environment as random effects. A new linkage map was developed to create windows of 20 adjacent SNPs for use in the GWAS. The two windows with largest effect for FY and FW were located on chromosome Omy9 and explained only 1.0-1.5% of genetic variance, thus suggesting a polygenic architecture affected by multiple loci with small effects in this population. One window on Omy5 explained 1.4 and 1.0% of the genetic variance for BW10 and BW13, respectively. Three windows located on Omy27, Omy17, and Omy9 (same window detected for FY) explained 1.7, 1.7, and 1.0%, respectively, of genetic variance for CAR. Among the detected 100 SNPs, 55% were located directly in genes (intron and exons). Nucleotide sequences of intragenic SNPs were blasted to the Mus musculus genome to create a putative gene network. The network suggests that differences in the ability to maintain a proliferative and renewable population of myogenic precursor cells may affect variation in growth and fillet yield in rainbow trout.

Parámetros genéticos para características de crecimiento, canal, calidad y espinas intramusculares en cachama blanca (Piaractus brachypomus) / Genetic parameters for growth, carcass, quality and intramuscular spine traits in white blanca (Piaractus brachypomus)

RESUMEN Los temas de la acuicultura en los que se requiere innovación e investigación están orientados al mejoramiento y al conocimiento genético de especies nativas. En este sentido, el presente estudio se concentró en estimar heredabilidades, correlaciones genéticas y fenotípicas para características de crecimiento, canal, calidad y espinas intramusculares derechas (EIMD), en cachama blanca (Piaractus brachypomus). La progenie de 12 hembras y 24 machos por fertilización artificial de una hembra por dos machos, es decir, doce familias de hermanos medios, fueron analizados por medio del paquete estadístico SAS 9.4 (SAS®, 2014). Se asumió un modelo lineal general univariado, con inclusión de los efectos fijos, como factores de entorno, estanque y edad y factores genéticos, como efectos aleatorios. Las heredabilidades, en general, para las variables de crecimiento, mostraron valores de medios a altos; para las variables de la canal presentaron valores bajos a medios; para las variables de calidad fueron bajos y, de particular interés para la EIMD, la magnitud de la estima fue de 0,11 ± 0,15. Las correlaciones estuvieron, generalmente, cercanas a la unidad entre características de crecimiento. Estas fueron significativamente positivas para peso corporal, a 180 días de edad, con la mayoría de variables, a diferencia con las variables de calidad, la correlación para rendimiento en canal con EIMD de -0,99 fue encontrada significativamente negativa. Los resultados del estudio destacan el potencial para mejorar características de crecimiento, de canal y de calidad, a través de la explotación de la variación genética aditiva observada.

ABSTRACT The topics of aquaculture in which innovation and research are required are directed towards the improvement and genetic knowledge of native species. In this sense the present study concentrated on the estimation of heritabilities, genetic and phenotypic correlations for growth, carcass, quality and right intramuscular spines (RIMS) in white cachama (Piaractus brachypomus). The progeny of 12 females and 24 males by artificial fertilization of a female by two males, that is to say twelve half-sib families, were analyzed by means of the statistical package SAS 9.4 (SAS®, 2014), assumed an univariate general linear model with inclusion of Fixed effects such as environmental factors, pond and age as fixed effects and genetic factors as random effects. Heritabilities in general for growth variables showed medium to high values; for carcass variables, presented low to medium values; And for the quality variables were low; For the RIMS the magnitude of the estimate was 0,11 ± 0,15. The correlations were generally close to unity between growth characteristics. These were significantly positive for body weight at 180 days of age with most variables unlike quality variables; the correlation for channel performance with RIMS of -0.99 was found to be significantly negative. The results of the study highlight the potential to improve growth, carcass and quality traits through the exploitation of the additive genetic variation observed in this study.

Efeito do peso ao abate nos rendimentos dos processamentos do pacu (Piaractus mesopotamicus) / Effect of body weight on processing yields of Pacu (Piaractus mesopotamicus)

The objective was to evaluate the effect of slaughter weight on the processing efficiency of Pacu (Piaractus mesopotamicus).The fish were cultivated in a soil vivarium and fed commercial feed. After ten months of cultivation, 96 fish were deadened, slaughtered, weighed and dissected to determine the yield of clean body, fillet and percentage of entrails. The weight classes analyzed were: CI - 135 to 285g; CII - 310 to 385g; CIII - 400 to 585g; CIV - 600 to 1.285g. For the variance analysis the data was grouped in four weight classes, and the regression equations were estimated regarding mean weight in each class. No effect of the weight class (P>0,05) was observed on the yield of clean body (RTL). However, there was a linear effect (P<0,05) of the weight classes in slaughter over the fillet yield (RF) and percentage of entrails. Pacus slaughtered in more elevated weight classes had greater filled yield. Thus, the fish destined to the fillet process should preferably be slaughtered at higher weights. The fish cultivated with the objective of being commercialized as a carcass or whole with entrails removed may be slaughtered at lower weights.

Características morfométricas, rendimento e composição do filé de tilápia do Nilo, Oreochromis niloticus, da linhagem tailandesa, local e do cruzamento de ambas / Morphometrics, fillet yield and fillet composition in Nile tilapia, Oreochromis niloticus, strains thai chitralada, brazil local and their hybrid

As características morfométricas, rendimento e a composição do filé foram pesquisadas em tilápia do Nilo Oreochromis niloticus, das linhagens tailandesas chitralada (Tai), local (Local, Norte do Paraná, Brasil), e da proveniente do cruzamento de ambas (Hbr, macho tailandesa x fêmea local). Ao início do experimento os peixes (n:900) apresentavam peso de 0,39+-0,20 e 0,45+-0,15 g e ao final 650,67; 534,25 e 360,00 g para as variedades Tai, Local e Hbr, respectivamente. Foram estabelecidas quatro razões morfométricas, sendo a razão entre altura da cabeça/ comprimento da cabeça da variedade Tai foi maior (P<0,05) quando comparada às duas outras linhagens. A linhagem Hbr apresentou maior rendimento em filé (39,05) (P<0,05) quando comparada à Local (38,00) e Tai (36,51), que não diferiram entre si (P>0,05). A composição centesimal do filé da linhagem Local apresentou menor teor de lipídios (1,88) (P<0,05) quando comparada à Hbr (2,44) e Tai (2,96), que também diferiram entre si, com menor teor de lipídios para a Hbr (P<0,05). O teor em proteína bruta, cinzas e umidade do filé não apresentaram diferenças significativas (P>0,05) entre as variedades

Morphometrics, fillet yield and fillet composition differences were researched in Nile tilapia, Oreochromisniloticus, strain thai-chitralada (Tai), Brazil (Local) Northern Paraná and their hybrid (Hbr, male Thailandx Brazilians female ). The experiment was designed entirely randomly with three treatments (strains) andthree repetitions per treatment in hapa nets in ponds. The initial weights were 0.39 ± 0.20, 0.45 ± 0.22 and0.41 ± 0.15 g for the strains Tai, Bras and Hbr, respectively. At the end of the experiment, the weights were650.67, 534.25 and 360.00 g for the same previous sequence, with statistically significant differencesbetween groups (P<0.05). Four morphometric proportions were established to characterise each group. For the ratio (head height)/(head length), the Tai strain was largest (P<0.05) as compared to the two otherstrains. The other morphometric proportions were not different (P>0.05). The strain Hbr produced(P<0.05) greater fillet yield (39.05%) when compared to Local (38.00 %) and Tai (36.51 %), the latter twowere not different from each other (P>0.05). Considering fillet composition, Local strain had the leastcrude lipid content of (1.88 %), as compared to Hbr (2.44 %) and Tai (2.96 %) which were significantlydifferent (P<0.05). Crude protein, ash and moisture of the fillets were not different (P> 0.05)