Growth Curve Parameters Research Articles

Statistical modelling of growth curve for longitudinal data on a feeding trial in goat breeds

The growth curve parameters were estimated extending a linear regression to higher degree polynomial with attempts to use also the biologically appealing Gombertz function. The data contained monthly weight records from weaning to the age of 14 months of kids in two Omani goat breeds Sahrawi and Jabbali used in a feeding trial assessing the effect of concentrate supplement (14% crude protein). The growth curve parameters were estimated within the fixed effects breed and feed concentrate level (2 or 3% of live body weight) with an extension to mixed models using animals as random effects. The parameters and model contrasting were performed with ML or REML as appropriate with relative comparison relying on AIC and significance testing of estimated parameters. The mixed model analyses were performed with publicly available R software package programs. The fixed effect cubic regression with linear random effect model fitted into the data. The higher level of concentrates improved the immediate post-weaning growth in the same way in the breeds while the subsequent growth curve differed with more pronounced weight increments in the Jabbali breed.

Integrated Analysis Reveals Genetic Basis of Growth Curve Parameters in an F2 Designed Pig Population Based on Genome and Transcriptome Data

Appropriate growth curves can reflect more sophisticated growth patterns of animals than body weight, and thus, the identification of genes and variants related to the growth curve parameter traits contributes to revealing the fine growth and development characteristics of livestock. However, the ability of single genome-wide association analysis (GWAS) and transcriptome analyses to identify valuable genes and variants is limited. In this study, based on genome and transcriptome data, the growth curve parameter traits of hybrid pigs were analyzed, and a set of genes and variants were identified. The Gompertz–Laird growth curve model was optimized to reveal the growth pattern of F2 individuals of Duroc × Erhualian pigs over four time points. Five growth parameters were estimated, including initial body weight (W0), instantaneous growth rate per day (L), coefficient of relative growth or maturing index (k), body weight at inflection point (Wi), and average growth rate (GR). These five parameters were subjected to a genome-wide association study, differential gene expression analysis, and weighted gene co-expression network analysis (WGCNA). In the study, 336 pigs were genotyped, and 39,494 SNP markers were used for each pig in the analysis. Thirty of these pigs were also included in the transcriptomics analysis. Based on genome and transcriptome data, the integrated analyses identified five putative SNPs (including INRA0056460 on chromosome X, DRGA0004151 on chromosome 3, INRA0056460 on chromosome X, H3GA0049324 on chromosome 17, and H3GA0037747 on chromosome 13) and 15 candidate genes (PDGFA, VEGFD, CSPP1, EFHC1, PIK3C3, ZZZ3, GCC2, MAPK14, ZPR1, ISG15, ANG, CEBPD, ZHX3, CTBP2, and MYNN). The functional analysis indicated that these candidate genes played important roles in cell division and differentiation, development and aging, and skeletal muscle and fat formation. Our results provide insight into the genetic mechanisms underlying the growth and development of hybrid pigs and offer a theoretical basis for genomic breeding.

Estimating genetic parameters and trends in growth curve traits of Zandi sheep using the SAEM algorithm.

The objectives of this study were to evaluate the influence of environmental effects on growth curve traits of Zandi lambs and estimate their genetic parameters with the best-fit animal model. For this purpose, live body weight (BW) records (n = 10,607) of 2,519 individuals (which were progeny of 278 rams and 1,485 ewes) were used to estimate genetic effects on growth curve traits from birth to yearling age of Zandi lambs. Using the Stochastic Approximation Expectation Maximization (SAEM) algorithm the growth curve parameters of five different mixed functions (i.e., Brody, Richards, Von Bertalanffy, Gompertz and Logistic) were obtained, then for the most appropriate model the genetic parameters were estimated using a Bayesian approach fitted multivariate animal model and ignoring or including maternal genetic effect. Except Richards model, all other mixed functions used here closely fitted actual BW records (R2 > 0.96). However, the Logistic function provided the best fit in every type. So, studied growth curve traits were estimated asymptotic weight which considered as mature weight (a), rate parameter (b), rate of maturing (k), and age (Ai)/weight (Wi) at the point of inflection. Of the fixed effects studied (i.e., gender, birth type, dam age, season and year of birth), the only non-significant relationship was the effect dam age on b and Ai. Based on the best-fitted model, posterior means of heritability estimates for a, b, k, Wi and Ai were 0.142 ± 0.036, 0.094 ± 0.029, 0.143 ± 0.063, 0.149 ± 0.039 and 0.029 ± 0.013, respectively. Posterior means of genetic correlations between mentioned traits ranged from -0.018 ± 0.069 (b-k) to 0.959 ± 0.029 (a-b), whereas the phenotypic correlation varied from -0.047 ± 0.014 (b-k) to 0.836 ± 0.007 (a-b). It was concluded that the model including only direct additive effect was sufficient to explain the variation in all investigated growth traits of Zandi lambs, selection for these traits results in slow genetic gain (due to the lack of sufficient genetic variation), but it would not be difficult to improve their mature weight and rate of maturing jointly. The results indicate that although the rate of genetic change for mature weight has been small (0.008 ± 0.003 kgyear-1; P < 0.05) but in the favorable direction for this breed.

Anthropometric measurements of children with neurofibromatosis type I: impact of plexiform neurofibroma volume and treatment.

In children and adolescents/young adults (CAYA) with neurofibromatosis type I (NF1), associations between anthropometric measurements, plexiform neurofibroma (pNF) tumor volume (TV), and treatment history are unknown. We retrospectively investigated anthropometrics in CAYA on the National Cancer Institute (NCI) NF1 Natural History Study who had pNF TV assessed by imaging (n = 106). We determined CDC height/weight percentiles and estimated Preece-Baines (PB) height growth curve parameters. We evaluated variables that could impact height/weight including: (1) pNF volume, (2) pNF directed therapy, and (3) serum IGF-1. 23% of males and 20% of females had height <5th percentile; 13% of males had weight <5th percentile. Estimated median final adult height for males was 171.6 cm (CDC 23rd percentile) and for females was 156.2 cm (CDC 14th percentile). Inverse associations between height and weight percentiles and pNF volume were observed (Spearman's r = -0.277, -0.216, respectively). Estimated median final height was not meaningfully affected by patients who received pNF-directed treatment with MEK inhibitor. 52% of low serum IGF-1 measurements were concurrent with a height percentile <5th. Greater than expected percentages of patients had height/weight <5th percentile, and median final adult heights were <CDC 25th percentile. pNF volume was inversely associated with height/weight percentiles. Children and adolescents/young adults with neurofibromatosis type I (NF1) seen at a research hospital have lower height and weight percentiles than normative populations. Growth percentiles are inversely associated with plexiform neurofibroma tumor volumes and impacted little by MEKi treatment history in this subset of patients. These findings align with prior investigations of growth in the NF1 population but are the first to examine the association with tumor burden.

Effect of genotype and nutritional and environmental challenges on growth curve dynamics of broiler chickens

The present study aimed to compare the dynamics of growth of various chicken genotypes exposed to heat stress, low-input diets, and free-range farming by using Gompertz model to gain insights into their capabilities to face environmental and nutritional challenges. Three in vivo trials (T1: heat stress, T2: low-input diets, and T3: free-range system) were conducted, involving a total of 671 animals. Five chicken genotypes were employed in each trial: 2 Italian local breeds, Bionda Piemontese (BP) and Robusta Maculata (RM), along with their crossbreeds with Sasso hens (BP×SA and RM×SA), and a commercial hybrid (Ross 308). One-day-old male chicks were individually identified, and the 5 genotypes were randomly allocated to different challenging conditions: T1 involved 2 environmental temperatures (thermoneutral vs. high temperature); T2 involved 2 diets (standard vs. low-input); T3 involved 2 rearing systems (conventional vs. free-range). The chickens were weighed once a week from their arrival until slaughtering, and the data were used to build growth curves using the Gompertz model. Chickens from different genotypes were slaughtered at varying ages based on their maturity. In all trials, the challenging conditions significantly reduced adult body weight (A; -31.0%) and maximum growth rate (MGR; -25.6%) of Ross chickens. In contrast, in T1 and T2, no significant changes were observed in the main growth curve parameters of local breeds and crossbreeds, while under free-range conditions, there was even an increase in the A and MGR of these genotypes. The crossbreeding was effective in increasing A and MGR of BP (+30.5% in BP×SA), as well as in improving the precocity and MGR of RM (+19.5% in RM×SA). Our findings highlight the effectiveness of the Gompertz model as a tool for evaluating birds' adaptability and confirm the greater ability of local breeds and crossbreeds to adapt to different challenges. In conclusion, our methodological approach could be used to choose the genotype most suited to the environmental context and confirm the potential advantages of crossbreeding for enhancing resilience and sustainability.

Copy number variations affecting growth curve parameters in a crossbred chicken population

Copy number variations (CNVs) are key structural variations in the genome and may contribute to phenotypic differences. In this study, we used a F2 chicken population created from reciprocal crossing between fast-growing Arian broiler line and Urmia native chickens. The chickens were genotyped by 60 K SNP BeadChip, and PennCNV algorithm was used to detect genome-wide CNVs. The growth curve parameters of W0, k, L, Wf, Wi, ti and average GR were used as phenotypic data. The association between CNV and growth curve parameters was carried out using the CNVRanger R/Bioconductor package. Five CNV regions (CNVRs) were chosen for the validation experiment using qPCR. Gene enrichment analysis was done using WebGestalt. The STRING database was used to search for significant pathways. The results identified 966 CNVs and 600 CNVRs including 468 gains, 67 losses, and 65 both events on autosomal chromosomes. Validation of the CNVRs obtained from the qPCR assay were 79 % consistent with the prediction by PennCNV. A total of 43 significant CNVs were obtained for the seven growth curve parameters. The 416 genes annotated for significant CNVs. Six genes out of 416 genes were most related to growth curve parameters. These genes were LCP2, Dock2, CD80, CYFIP1, NIPA1 and NIPA2. Some of these genes in their biological process were associated with the growth, reproduction and development of cells or organs that ultimately lead to the growth of the body. The results of the study could pave the way for better understanding the molecular process of CNVs and growth curve parameters in birds.

Genome-wide association study of growth curve parameters reveals novel genomic regions and candidate genes associated with metatarsal bone traits in chickens

The growth and development of chicken bones have an enormous impact on the health and production performance of chickens. However, the development pattern and genetic regulation of the chicken skeleton are poorly understood. This study aimed to evaluate metatarsal bone growth and development patterns in chickens via non-linear models, and to identify the genetic determinants of metatarsal bone traits using a genome-wide association study (GWAS) based on growth curve parameters. Data on metatarsal length (MeL) and metatarsal circumference (MeC) were obtained from 471 F2 chickens (generated by crossing broiler sires, derived from a line selected for high abdominal fat, with Baier layer dams) at 4, 6, 8, 10, and 12 weeks of age. Four non-linear models (Gompertz, Logistic, von Bertalanffy, and Brody) were used to fit the MeL and MeC growth curves. Subsequently, the estimated growth curve parameters of the mature MeL or MeC (A), time-scale parameter (b), and maturity rate (K) from the non-linear models were utilized as substitutes for the original bone data in GWAS. The Logistic and Brody models displayed the best goodness-of-fit for MeL and MeC, respectively. Single-trait and multi-trait GWASs based on the growth curve parameters of the Logistic and Brody models revealed 4 618 significant single nucleotide polymorphisms (SNPs), annotated to 332 genes, associated with metatarsal bone traits. The majority of these significant SNPs were located on Gallus gallus chromosome (GGA) 1 (167.433–176.318 Mb), GGA2 (96.791–103.543 Mb), GGA4 (65.003–83.104 Mb) and GGA6 (64.685–95.285 Mb). Notably, we identified 12 novel GWAS loci associated with chicken metatarsal bone traits, encompassing 35 candidate genes. In summary, the combination of single-trait and multi-trait GWASs based on growth curve parameters uncovered numerous genomic regions and candidate genes associated with chicken bone traits. The findings benefit an in-depth understanding of the genetic architecture underlying metatarsal growth and development in chickens.

Genetic analysis of body weight and growth curve parameters in Muzaffarnagari sheep of India.

The objective of this study was to estimate genetic effects on parameters of the Brody and Richards growth curves using body weight records from birth to 12 months of age on 2287 Muzaffarnagari lamb for a period of 29 years (1976-2004). Estimated growth curve parameters were analysed using six univariate animal models, and genetic correlations among and between the parameters of each function and between parameters of the functions and observed birth and yearling weights were estimated using bivariate analyses. Significant environmental factors including birth year, sex, season, birth status and dam parity were included as fixed effects in all models. Likelihood ratio tests indicated that maternal genetic effects were significant only for birth weight (BW) and degree of maturity at birth (u0 ) for the Brody and Richards functions. For these traits, direct heritabilities were similar (0.21, 0.19 and 0.17, respectively), but the estimated maternal heritability for BW (0.18) was twice that of u0 for both functions. Heritabilites for yearling weight and asymptotic final body weights for the Brody and Richards functions were 0.28, 0.17 and 0.21, respectively. The remaining growth curve parameters were lowly heritable, ranging from zero for the predicted degree of maturity at the age of maximum growth rate for the Richards function to 0.08 for the maturing rate parameter of the Brody function. Genetic correlations between corresponding parameters for different growth functions exceeded 0.88. Our results showed that the Brody and Richards functions had similar genetic architecture, but the Richards function had no apparent advantages over the more easily interpreted Brody function. Failure to identify maternal genetic effects on maturing rate parameters suggested that both functions failed to identify potentially important maternal genetic effects. Therefore, there is no usefulness of estimated growth curve parameters in selection compared to the simple multi-trait genetic evaluations of individual body weights.

Introducing exceptional growth mining-Analyzing the impact of soil characteristics on on-farm crop growth and yield variability.

Sustainable intensification of agriculture requires understanding of the effect of soil characteristics and nutrient supply on crop growth. As farms are increasing in size by acquiring small fields from various farmers, the soil characteristics and nutrient supply might be very different from field to field, while at the same time specific soil properties might limit the nutrient uptake. As a result, there might be a large number of heterogeneous reasons why crop growth varies significantly. New data analysis techniques can help to explain variability in crop growth among fields. This paper introduces Exceptional Growth Mining (EGM) as a first contribution. EGM instantiates the data mining framework Exceptional Model Mining (EMM) such that subgroups of fields can be found that grow exceptionally in terms of three growth parameters (high/low maximum growth, steep/flat linear growth and early/late midpoint of maximum growth). As second contribution, we apply EGM to a case study by analyzing the dataset of a potato farm in the south of the Netherlands. EGM consists of (i) estimating growth curves by applying nonlinear mixed models, (ii) investigating the correlation between the estimated growth parameters, and (iii) applying EMM on these growth curve parameters using a growth curve-specific quality measure. By applying EGM on the data of the potato farm, we obtain the following results: 1) the estimated growth curves represent the variability in potato tuber growth very well (R2 of 0.92), 2) the steepness of the growth curve has a strong correlation with the maximum growth and the midpoint of maximum growth, and the correlation between the midpoint of maximum growth and maximum growth is weak, 3) the subgroup analyses indicate that: high values of K correspond to high maxima; low values of K correspond to low maxima, steep growth curves', and a late midpoint of halfway growth; Mg influences the midpoint of the growth curve; values of B are higher on dry soils with high tuber growth, while low values of B are found on wet soils with high tuber growth; high values of Zn, Mn, and Fe are found in subgroups with low tuber weight, probably related to the soil's low pH. In summary, this paper introduces EGM to obtain understanding in crop response to soil properties and nutrient supply. In addition, EGM provides a way to analyze only small parts of a large dataset, such that the impact of soil factors on growth can be analyzed on a more detailed level than existing methods.

Determination of the effect of the dam age, birth type, and sex on growth curve traits of hair goat kids.

This study was conducted to investigate the best-fit growth curve and dam age, sex, and birth type effect on growth curve traits of hair goat kids. Monthly 3858 test day body weight (BW) records of 643 hair goat kids from birth to 150days of age were used to determine the best-fit growth curve and estimate growth curve parameters with Gompertz and Von Bertalanffy models. The BW records were assigned to three groups: dam age (3, 4, 5, 6, 7years), sex (female, male), and birth type (single, twin). The Gompertz model gave more consistent results than the Von Bertalanffy model according to the goodness of fit criteria. Dam age had no significant effect on any of the growth curve traits. Sex of kids showed a significant effect on maturity index (parameter K) (P < 0.001), estimated mature body weight (parameter A), and weight at point of inflection (IPW) (P < 0.01). Also, birth type had a significant effect on initial/birth weight (parameter B) and parameter K (P < 0.001). Age at point of inflection (IPT) was not affected by any of the factors. Twin kids had a higher maturity index than singles while females higher than males. In conclusion, the Gompertz model was the most suitable model for hair goat kids for selection strategies. For proper selection, the effect of sex and birth type on growth curve traits should be considered by hair goat breeders.

Emotional exhaustion across the workday: Person-level and day-level predictors of workday emotional exhaustion growth curves.

Despite empirical findings that have established the dynamic nature of emotional exhaustion (EE), the temporal processes underlying the development of EE over meaningful spans of time have largely been ignored in research. Drawing from theories that outline the roles of resources and demands at work (Demerouti et al., 2001; Halbesleben et al., 2014; Hobfoll, 1989; ten Brummelhuis & Bakker, 2012), the present study developed and tested hypotheses pertaining to the form and predictors of workday EE trajectories. Experience sampling methodology was utilized to assess the momentary EE of 114 employees three times per day over a total of 925 days and 2,808 event-level surveys. Within-day EE growth curves (i.e., intercepts and slopes) were then derived, and the variance of these growth curve terms was partitioned into within-person (i.e., variance in growth curve parameters across days for each person) and between-person (i.e., variance in average growth curve parameters across people) sources. Results supported an increasing pattern of EE across the workday and also demonstrated substantial between- and within-person variance in intercepts (i.e., start) and slopes (i.e., growth) over the workday. In addition, support was found for a set of resource-providing and resource-consuming predictors of EE growth curves, including customer mistreatment, social interactions with coworkers, prior evening psychological detachment, perceived supervisor support, and autonomous and controlled motivations for one's job. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The effect of oregano essential oil on Feed Passage Syndrome in broilers: 1. Assessment under field conditions

Feed Passage Syndrome (FPS) is a prevalent condition that includes wet excreta, with undigested feed, and loss of feed efficiency, with multiple predisposing factors involved. Alternatives to antimicrobials, including phytogenics, are being studied to control this process. This study aimed to assess oregano essential oil (OEO) in broilers subjected to a natural field FPS challenge. Four broiler houses (two males; two females) presenting FPS were divided into two groups per house and assigned to a control or OEO-treated group through drinking water for five days. The FPS was characterized by >30% wet droppings, >50% with undigested feed, <5% with desquamated mucosa, >10% birds with enteritis, and 90% with undigested feed in the lower ileum, and flocks clinically positive for dysbacteriosis. After a five-day treatment, OEO-treated birds showed fewer abnormal droppings (P < 0.05), reduced the prevalence of dysbacteriosis (P = 0.0404), and a progressively recovering BW. The OEO treatment showed to influence the Gompertz growth curve parameters (growth rate, P = 0.0165; inflection point, P = 0.0359), potentially reducing the age at the target market weight in 0.8 days. In conclusion, the results indicate that the OEO treatment in drinking water for broilers naturally challenged with the Feed Passage Syndrome may improve excreta characteristics and attenuate the negative impact of the syndrome on the BW.

Emmetropic eye growth in East Asians and non-East Asians.

To compare axial length (AL) growth curves in East Asian (EA) and non-EA emmetropes. A meta-regression of 28 studies with emmetrope-specific AL data (measured with optical biometry) was performed. Emmetropia was defined as spherical equivalent refraction (SER) between -0.50 and +1.25 D, determined under cycloplegia if the mean age was ≤20 years. The AL growth curve (mean AL vs. mean age) was first fitted to the full dataset using a weighted nonlinear mixed-effects model, before refitting the model with ethnicity as a two-level grouping variable (EA vs. non-EA). Ethnic differences in growth curve parameters were tested using the Wald test. A total of 3331 EA and 1071 non-EA emmetropes (mean age: 6.5-23.1 years) were included. There was no evidence of an ethnic difference in either final AL (difference: 0.15 mm, 95% CI: -0.04 to 0.35 mm, p = 0.15) or initial AL, as represented by the amount that the final AL needed to be offset to obtain the y-intercept (difference: -2.77 mm, 95% CI: -10.97 to 5.44, p = 0.51). Likewise, AL growth rate (curve steepness) did not differ between ethnic groups (difference: 0.09, 95% CI: -0.13 to 0.31, p = 0.43). Collectively, AL growth rate decreased from 0.24 mm/year at 6 years of age to around 0.05 mm/year at 11 years of age, after which it dipped below the repeatability of optical biometry (±0.04 mm) and practically plateaued around 16 years of age (final AL: 23.60 mm). EA and non-EA emmetropes have comparable AL growth curves.

PREDICTING PREECLAMPSIA DURING PREGNANCY: THE VALUE OF BLOOD PRESSURE MEASUREMENT TRENDS TO IDENTIFY WOMEN AT HIGHEST RISK

Objective: Hypertensive disorders of pregnancy, including preeclampsia are serious complications increasing the risk of morbidity and mortality for both mother and baby. We hypothesise that blood pressure (BP) trends during pregnancy are a useful, accessible and practical predictor of preeclampsia onset. In this study we aimed to determine: (i) the association between mean arterial pressure (MAP), Systolic BP (SBP) and Diastolic BP (DBP) at time of pregnancy booking with subsequent preeclampsia development, and (ii) whether repeated measures of BP thought pregnancy can improve prediction of preeclampsia. Design and method: Data were from 11,008 women with a singleton pregnancy who received antenatal care and gave birth across three metropolitan Sydney hospitals 2017-2020. BP measurements were represented as MAP, SBP and DBP. Three sets of logistic regression models were used to yield odds ratios (ORs) with 95% confidence intervals (CIs) for the association of preeclampsia with: (1) booking BP, (2) summary BP measurements (mean, maximum, standard deviation (SD)) and (3) growth curve parameters (mean BP, slope and standard error of slope) derived from mixed effects models, representing each women's BP trajectory. Akaike's information criterion was used to determine the ‘best fitting’ model. Results: Booking BP was taken between 5 and 15 weeks of pregnancy (median 14 weeks). There were 80,624 BP measurements taken throughout pregnancy, the number and timing varied between women: median (min, max): 8(3,17) measurements. There were 191 cases of preeclampsia. Booking MAP before 16 weeks’ gestation (OR (95%CI) (per SD higher) (1.78 (1.53, 2.06) yielded a better model fit than SBP (1.67 (1.44, 1.94) or DBP (1.66 1.43, 1.96)) for preeclampsia. Of the summary measures, maximum MAP yielded the best fitting model (OR (95%CI) (per SD higher): 4.37 (3.76, 5.11). Growth curve parameters were significant predictors of preeclampsia, and substantially improved model fit in comparison to booking BP alone. Conclusions: Booking visit MAP was more strongly associated with preeclampsia than SBP or DBP. Using repeated BP measures, in the form of summary MAP measures and BP trajectories, improved the prediction of preeclampsia.

Genetic Parameter Estimates of Growth Curve and Feed Efficiency Traits in Japanese Quail.

This study aimed to estimate heritabilities for weekly body weight traits, the Gompertz growth curve parameters, and feed efficiency characteristics, as well as genetic correlations among characteristics. A total of 700 Japanese quails with pedigree records were used in this study. Body weight and feed consumption were measured individually on a weekly basis. Using weekly body weight data, the growth model parameters were estimated for each bird using the Gompertz nonlinear regression model. Multi-trait variance-covariance matrices were obtained with Bayesian inference using the Gibbs sampler. While estimates of high heritability (0.59 to 0.61) were found for weekly body weight traits, estimates of moderate heritability (0.23 to 0.37) were determined for feed intake and feed conversion efficiency traits. The estimated heritabilities for the parameters of the Gompertz model and inflection point coordinates were moderate (0.37 to 0.47). While genetic correlations between feed intake and body weight characteristics were positive and moderate (0.28 to 0.49), the genetic correlations between feed conversion efficiency and body weight traits were positive and strong (0.52 to 0.83). It has been concluded that the moderate negative genetic relationship between feed conversion efficiency and body weight may constrain selection studies. Due to the weak genetic correlation between the asymptotic body weight parameter of the Gompertz model and the feed conversion efficiency, it is thought that the total genetic gain will be greater if the mature weight parameter is also used as a selection criterion in genetic improvement studies.

Crossbreeding to improve local chicken breeds: predicting growth performance of the crosses using the Gompertz model and estimated heterosis

The present study aims to validate the Gompertz model to predict the growth performance of chicken crosses according to growth curve parameters of the parental lines and the estimated heterosis for each curve parameter. A total of 252 one-day-old chicks of both sexes belonging to 6 genotypes, including Ross 308, Sassò (SA), Bionda Piemontese (BP), and Robusta Maculata (RM), and the crosses between these local breeds and SA (BP×SA and RM×SA) were randomly allocated in 18 pens (3 pens/genotype) in mixed-sex groups (14 animals/pen; 7 females and 7 males). The individual body weight (BW) of all birds was recorded once a week from hatching until slaughtering (81 d for Ross 308; 112 d for SA, 140 d for the other genotypes). We drew up our final dataset with 240 birds (40 birds/genotype; 20 females and 20 males). The growth curve of each genotype was described using the Gompertz model, and the heterosis for each growth curve parameter was calculated as the difference between F1 crosses and the average of parental breeds. The predicted growth curve parameters were evaluated by cross-validation. The Gompertz model accurately estimated the growth curves of all the genotypes (R2 > 0.90). Heterosis was significant for almost all growth curve parameters in both crosses (P < 0.05). Heterosis ranged from -13.0 to +11.5%, depending on parameters, but varied slightly between the crossbreeds (BP×SA and RM×SA). The predicted values of adult BW, weight at the inflection point, and maximum growth rate were overestimated for BP×SA and underestimated for RM×SA, with a mean error between observed and predicted values <│2.7│% for all the curve parameters. In conclusion, the growth performance of chicken crosses between local breeds and commercial strains can be accurately predicted with Gompertz parameters of the parental lines adjusting for heterosis.

Comparative Transcriptome Analyses of Leg Muscle during Early Growth between Geese (Anser cygnoides) Breeds Differing in Body Size Characteristics.

Goose is an important poultry commonly raised for meat. The early growth performance of geese significantly influences their market weight and slaughter weight, affecting the poultry industry's economic benefits. To identify the growth surge between the Shitou goose and the Wuzong goose, we collected the early growth body traits from 0 to 12 weeks. In addition, we investigated the transcriptomic changes in leg muscles at the high growth speed period to reveal the difference between the two geese breeds. We also estimated the growth curve parameters under three models, including the logistic, von Bertalanffy, and Gompertz models. The results showed that except for body length and keel length, the best-fitting model between the body weight and body size of the Shitou and Wuzong was the logistic model. The growth turning points of Shitou and Wuzong were 5.954 and 4.944 weeks, respectively, and the turning point of their body weight was 1459.01 g and 478.54 g, respectively. Growth surge occurred at 2-9 weeks in Shitou goose and at 1-7 weeks in Wuzong goose. The body size traits of the Shitou goose and Wuzong goose showed a trend of rapid growth in the early stage and slow growth in the later stage, and the Shitou goose growth was higher than the Wuzong goose. For transcriptome sequencing, a total of 87 differentially expressed genes (DEGs) were identified with a fold change ≥ 2 and a false discovery rate < 0.05. Many DEGs have a potential function for growth, such as CXCL12, SSTR4, FABP5, SLC2A1, MYLK4, and EIF4E3. KEGG pathway analysis identified that some DEGs were significantly enriched in the calcium signaling pathway, which may promote muscle growth. The gene-gene interaction network of DEGs was mainly related to the transmission of cell signals and substances, hematological system development, and functions. This study can provide theoretical guidance for the production and breeding management of the Shitou goose and Wuzong goose and help reveal the genetic mechanisms underlying diverse body sizes between two goose breeds.

Sex-Determined Growth of Yearling Pacific Oysters (Crassostrea gigas)

The sexes of sequentially hermaphroditic cupped oysters are both environmentally and genetically determined. Sex is also associated with growth or body size, females being larger than males of the same age on average. Whether sex determines size or size determines sex has not been resolved. To examine the relationship between growth and sex, 1,360 tagged individuals from six F2 families of Pacific oyster Crassostrea gigas were reared through their second summer in Thorndyke Bay, Washington; individual live weights were recorded for 5 consecutive months, starting in June. At the last weighing, microscopic examination of gonadal tissue revealed four “sexes” in the cohort, females (43% of cohort), males (29%), hermaphrodites (2%), and sex-undetermined individuals with no gametes (26%). Live weights were fit to various sigmoidal growth curves (logistic, Gompertz, and Richards) with fixed and random parameters to account for individual variation. The best fitting curves suggested that growth of the cohort was exponential until late August, when temperatures declined and more than 70% of final weight had been gained. Individual live weights, growth-curve parameters, and growth measures were fit to general linear models with family and sex classification variables. Family-by-sex interaction was significant in many such analyses. Females were larger than males on average and appeared to attain their size advantage from superior growth characteristics rather than from initial size. Males were strikingly either like females or like the smaller sex-undetermined oysters with respect to growth comparisons within family. Sex-undetermined oysters may have been “true” males that were too small to mature as yearlings, though a size-threshold for maturation was not apparent. Genetically determined sex and family genetics appeared to control growth.

Population dynamics and yield estimation of Common Carp (Cyprinus carpio, Linnaeus, 1758) in Ayalew reservoir, Gamo Zone, Southern Ethiopia

Common carp (Cyprinus carpio) is an introduced fish species in Ayalew reservoir. This study provides the first results on fishery dynamics of the species in the reservoir. The study was aimed at estimating important population dynamics parameters and production potential. Total length (TL) and total weight (TW) data were collected from a total of 276 fish samples (141 females and 135 males). The obtained data were analyzed using FiSAT II software. Jones length-based cohort analysis model and length-based Thompson and Bell yield prediction models were employed to estimate the population and production potential. The mean total length was 26 cm and the dominant length groups ranged from 17 to 33 cm were 87%. The length-weight relationship parameters were (TW = 0.0565TL2.53, R2 = 0.95) and the condition factor K = 1.29. The parameters of von Vertalanffy growth curve were L∞ = 41 cm, k = 0.52, to = -2.29, θ = 2.9 and A0.95 = 5.5 years. The estimated values of the total, natural and fishing mortalities were Z = 1.23, M = 0.55 and F = 0.68, respectively. The current exploitation rate was 0.55 which indicates slightly overexploitation. The estimated fish population and the annual fish yield were 59,304 and 1.5 tons, respectively. However, investigation on reproductive biology, limnolocal aspects and stock enhancements should be required for the sustainability of these resources.

Effects of Sex and Rearing Season on Body Weight Gain and Growth Curve Parameters of Local Chickens in Niger

Local chicken breeding is widespread in Niger, a country with harsh environmental conditions. This study aimed to investigate the effects of sex, temperature, and hygrometry variations on the body weight gain and growth curve of local Nigerien chickens. Two groups of local chickens were followed from hatching to 20 weeks of age. The first and second groups consisted of 96 and 124 chickens, respectively. Three seasons were identified based on continuously recording ambient temperature and humidity over a year. The dry and warm seasons (February, March, April, and May), the wet and warm seasons (June, July, August, and September), and the dry and cold seasons (October, November, December, and January). The average hatch weight was about 24 g, and monthly body weight gains ranged from 100 to 360 g. Asymptotic weights were 2214.02 ± 69.94 g and 1776.93 ± 63.57 g for roosters and 1380.25 ± 25.96 g and 1433.08 ± 71.24 g for hens. The sexual maturity rates indicate that hens are more precocious than roosters. Sex and season had significant impacts on the growth performance of the chickens. In conclusion, the results of the present study indicated that the optimal time to raise local chickens in rural Niger is from June to January, and males are better candidates for meat production. Keywords: Growth curve, Hygrometry, Local chicken, Temperature, Weight gain