Effect of long-term divergent selection on growth characteristics in Japanese quail

The potential post-hatching growth of domestic birds is sufficiently described by the Gompertz function

It has been hypothesised that, for post-hatching domestic birds reared under good conditions, the relative growth rate R = (dW/dt)/W = dlnW/dt is a linear function of lnW; W is body weight. It followed that dW/dt = B.W.ln(A/W), where A is mature weight, and, by integration, that weight by time is described by a Gompertz function: W_t = A.exp.(-exp(-(G₀ - B.t)), where W_t is weight at time t d, B is the rate parameter d^-1, and G₀ = -ln(-ln(W₀/A)).Where growth data published in the literature did not show this relationship, it was likely to be caused by sub-optimal conditions for maximum growth, such as inadequate nutrition or other factors.Published data, which have been diligently examined from both sexes and nine species, over 400-fold range of degree of maturity was seen, collected over nearly a century of data from four continents, which strongly corroborated the hypothesis.The data were not in agreement with other functions using three parameters and made functions with four or more parameters superfluous. The relationship between R and lnW should be carefully examined before subjecting any data set to further analysis.

Effects of Fruit Sizes of Two Camellia Trees on the Larval Sizes of Curculio styracis (Roelofs, 1875): Testing the Endoparasitoid Body Size Hypothesis

Simple Summary

In endoparasitoids that feed within small discrete resource patches, such as seeds or fruits, body size could be subject to a trade-off: larger size could lead to increased overall fitness but could simultaneously increase the risk of resource depletion and starvation, resulting in a body size just below the host holding capacity. We analyzed the relationship of the larval size of the within-fruits-developing curculionid beetle Curculio styracis (Roelofs, 1875) and the size of the fruits of its two congeneric host species of Camellia to test this hypothesis. A logistic model can most accurately describe larval size in association with host-fruit size after a series of models were tested. Based on the characteristics of the optimal model, the hypothesis seemed to be confirmed because larvae that developed in host plant with larger fruits had a larger size, and larval size in both host species remained only a little below the host-fruit capacity. The novelty of the study is that this hypothesis is being tested in a more formal way using appropriate mathematical models.

Abstract

The endoparasitoid body size hypothesis suggests that the size of larvae that develop in a single host should be subject to a trade-off: larger size could lead to increase overall fitness but could simultaneously increase the risk of resource depletion and starvation, resulting in a body size just below the host holding capacity. However, this hypothesis has not been rigorously tested using mathematical models thus far. The camellia weevil, C.styracis (Coleoptera: Curculionidae), is a notorious pest attacking fruits of Camellia oleifera Abel. and C. meiocarpa Hu., in which the larvae develop within a single fruit and larval development is limited by the available food resources. We developed a feasible method to test this hypothesis. First, five models were used to describe the relationship between larval mass and host size. Then, the minimum fruit threshold that had to be met for ad libitum larval development and the corresponding larval size (W_a) of this threshold were calculated based on the characteristics of the optimal model. Finally, the difference between the measured larval size and the predicted larval size (W_a) was determined. The results showed that (1) the data were better described by a logistic function than any other equation; (2) larval size in both host plants increased with increasing fruit size until leveling off when the fruits were large enough to allow unconstrained larval development; (3) larval size remained just below the host-fruit holding capacity, as there was no difference between the measured and predicted larval sizes (W_a); and (4) larvae developed in host plant with larger fruits had a larger size. These results confirmed the endoparasitoid body size hypothesis.

Influences of Dietary Supplementation with Maca (Lepidium meyenii) on Performance, Parameters of Growth Curve and Carcass Characteristics in Japanese Quail

Simple Summary

It is known that the bioactive compounds (N-benzyl-palmitamide, benzyl isothiocyanate, glucosinolates and phenolics) in the maca plant are appetizing, as well as having antioxidant effects and improving reproductive ability. The aim of this study was to determine the effects of adding maca plant powder to the ration at different levels on growth, slaughter carcass, partial egg production and some reproductive characteristics of Japanese quail (Coturnix coturnix japonica). Addition of maca powder to the diet increased the feed consumption but did not affect growth, slaughter carcass, partial egg production or fertility. In addition, maca powder reduced embryonic deaths and improved chick quality. According to these results, the positive effects of short-term application of maca powder are not observed during the fattening period in Japanese quails.

Abstract

Maca plant contains rich nutrients and in addition, it has various bioactive substances (N-benzyl-palmitamide, benzyl isothiocyanate, glucosinolates and phenolics). It is used to improve reproductive properties and has antioxidant effects for both humans and animals. The aim of this study was to determine the effects of adding maca plant powder to the ration at different levels on growth, slaughter carcass, partial egg production and some reproductive characteristics in Japanese quail (Coturnix coturnix japonica). The experimental groups were formed by adding 0% (control), 0.05% and 0.1% maca powder to the diet, and a total of 300 birds were used. Growth (weekly body weights, parameters of Gompertz growth function), feed efficiency and carcass characteristics of quails in the 42-day fattening trial were determined. Reproductive characteristics were measured up to 22 weeks of age. Addition of maca powder to the diet increased the feed consumption (p < 0.05) but did not affect body weights at 35 and 42 days of age, β₀ and β₁ parameters or point of inflection weight of the Gompertz model, carcass traits, partial egg production or fertility. It may be advisable to add 0.1% maca powder to the diets of breeders. Besides, maca powder reduced embryonic deaths and improved chick quality (both p < 0.05). It is thought that different results for reproductive traits can be obtained if maca powder is used for a longer period in the diets of breeder quail flocks.

Prediction and optimization of slaughter weight in meat-type quails using artificial neural network modeling

Carcass yield of meat-type quails is strongly correlated with the weight of the birds at slaughter (slaughter weight [SW]; body weight at 45 D of age). Moreover, prediction of superior animals for SW at the earlier stages of the rearing period is favorable for producers. Therefore, the aim of the present study was to predict and optimize SW of Japanese quails based on their early growth performances, sex, and egg weight as predictors through artificial neural network (ANN) modeling. To construct the ANN model a feed-forward multilayer perceptron neural network structure was used. Moreover, sensitivity analysis was used to arrange the predictors in the ANN model(s) according to their predictive importance too. In addition, the optimization process was conducted to determine the optimum values for the input variables to yield maximum SW. The best-fitted network on input data to predict SW in Japanese quails was determined with 7 neurons in the input layer, 11 neurons in the hidden layer, and one neuron in the output layer. The coefficient of determination (R²) was 0.9404, 0.9359, and 0.9223 for training, validation, and testing phases, respectively. For the corresponding phases, SEM were also 51.8854, 52.2764, and 55.2572, respectively. According to sensitivity analysis, the most important input variable for prediction of SW was body weight at 20 D of age (BW20), whereas the less important input variables were weight of the birds at hatch and body weight at 5 D of age. The results of the neural network optimization indicated that all the input variables, except for BW20, were very similar but slightly higher than mean values (μ for each input variable). The results of this study suggest that the ANN provides a practical approach to predict the final body weight (SW) of Japanese quails based on early performances. Moreover, phenotypic selection for higher values of early growth traits did not ensure the achievement of maximum SW, except for BW20.

Effects of Multi-Trait Selection on Phenotypic and Genetic Changes in Japanese Quail (Coturnix coturnix japonica)

The present study in Japanese quail was aimed to develop multi-trait genetic selection program for a meat type sire line utilizing the mixed-model methodology. In total, 2000 pedigreed quail were formed the basis of the research where a multi-trait animal model was performed. A flock consisting of a total of 160 families (1 male: 3 female) was developed from the initial flock (base population of sire line), so as to obtain a selection flock sire line. Body weight at 5 weeks of age was chosen as a primary selection criterion in flock. The age at point of inflection derived from Gompertz growth curve, feed conversion ratio between 3 to 5 weeks of age, and carcass yield at 5 week of age were determined as selection criteria. Multi-trait BLUP methodology was carried out for genetic improvement of birds. In flock, 25 percent of males and females with highest breeding value were selected to produce next generation. Genetic parameter estimates, realized genetic parameters, selection responses, and genetic trends were obtained. Significant (P<0.01) selection responses for body weight, age at point of inflection, feed conversion ratio, and carcass yield traits on generations were observed. The results of the study revealed that the negative genetic relationships exhibited between some studied traits had overcame by modern poultry breeding methods such as selection via multi-trait BLUP.

Some novel growth functions and their application with reference to growth in ostrich

Four novel growth functions, namely, Pareto, extreme value distribution (EVD), Lomolino, and cumulative β-P distribution (CBP), are derived, and their ability to describe ostrich growth curves is evaluated. The functions were compared with standard growth equations, namely, the monomolecular, Michaelis-Menten (MM), Gompertz, Richards, and generalized MM (gMM). For this purpose, 2 separate comparisons were conducted. In the first, all the functions were fitted to 40 individual growth curves (5 males and 35 females) of ostriches using nonlinear regression. In the second, performance of the functions was assessed when data from 71 individuals were composited (570 data points). This comparison was undertaken using nonlinear mixed models and considering 3 approaches: 1) models with no random effect, 2) random effect incorporated as the intercept, and 3) random effect incorporated into the asymptotic weight parameter (Wf). The results from the first comparison showed that the functions generally gave acceptable values of R2 and residual variance. On the basis of the Akaike information criterion (AIC), CBP gave the best fit, whereas the Gompertz and Lomolino equations were the preferred functions on the basis of corrected AIC (AICc). Bias, accuracy factor, the Durbin-Watson statistic, and the number of runs of sign were used to analyze the residuals. CBP gave the best distribution of residuals but also produced more residual autocorrelation (significant Durbin-Watson statistic). The functions were applied to sample data for a more conventional farm species (2 breeds of cattle) to verify the results of the comparison of fit among functions and their applicability across species. In the second comparison, analysis of mixed models showed that incorporation of a random effect into Wf gave the best fit, resulting in smaller AIC and AIC values compared with those in the other 2 approaches. On the basis of AICc, best fit was achieved with CBP, followed by gMM, Lomolino, and Richards functions, respectively. The exponential, MM, Pareto, and EVD equations produced negative values for initial weight (W0) if left unconstrained. The Gompertz equation, in spite of having a fixed inflection point and therefore being less flexible, gave accurate estimates of both W0 and Wf and an acceptable goodness of fit favored by having fewer parameters than the other sigmoidal functions. Nevertheless, all the sigmoidal functions appeared appropriate in describing the growth trajectory of male and female ostriches to a reasonable level of accuracy.

Establishment of optimum regression model and determination of relationships between body measurements and slaughter traits in Japanese quails by path analysis

Path analysis was used to investigate direct, indirect and total effects of some morphological measurements on slaughter and carcass traits in Japanese quails. Bodyweight, shank length, shank diameter, breast circumference and body length measurements were taken from 219 Japanese quails. Bivariate correlations between carcass weight and morphological traits in quails ranged from 0.405 to 0.864. The direct effect of bodyweight on carcass weight was the strongest in the study and (path coefficient of 0.85) positively influenced carcass weight (P < 0.01). The direct effect of other linear-type traits on carcass weight was non-significant as revealed by t-test (P > 0.05). These traits were indirectly realised mostly by shank diameter. Thus, they were dropped from the final regression equations to obtain much more simplified prediction models. The optimum multiple regression equation for Japanese quails included bodyweight, with coefficient of determination (R2) of 0.7463. The correlation between characters was determined in more detail by using path analysis in this study. Thus, it was shown that path analysis could be used for selecting a variable. The forecast indices obtained in this study could aid in weight estimation, selection and breeding programs.

Effects of slaughter age and mass selection on slaughter and carcass characteristics in 2 lines of Japanese quail

The aim of this study was to evaluate the relationship between slaughter age and slaughter-carcass characteristics in 2 quail lines. With this aim, a Japanese quail flock subjected to mass selection to increase BW for 4 generations and a control flock that randomly mated for 4 generations were used. Birds of both lines were slaughtered at 4, 5, 6, 7, and 8 wk of age. Weights of carcass, breast, leg, wing, edible inner organs, and abdominal fat, and their percentages in BW were measured. Short-term mass selection for increased BW resulted in an increase for all slaughter and carcass traits, except edible inner organ percentage. Slaughter age had a significant effect on the studied traits, indicating that the BW and weight of carcass, carcass parts, abdominal fat, edible inner organs, and percentage of abdominal fat increased with increased slaughter age. Conversely, the carcass yield and percentages of carcass parts and edible inner organs were decreased with an increase in slaughter age. The present study showed that deterioration in carcass quality occurred with an increase in slaughter age. Furthermore, the differences between the carcass weights over the different ages ranged between 16.83 to 22.45% in favor of the selection line after a short-term mass selection.

Exigências nutricionais de codornas

As exigências nutricionais de codornas diferem das de frangos e de galinhas poedeiras. Igualmente, as exigências de codornas japonesas também são distintas das de codornas europeias. Codornas exigem mais proteína (aminoácidos), menos cálcio na ração e digerem melhor os aminoácidos dos alimentos em comparação e a energia de alimentos fibrosos. Esses animais ainda aproveitam a energia do milho e do farelo de soja na mesma proporção que os frangos. Da mesma forma que os frangos, as codornas exigem mais energia para mantença, quando alojadas no piso, e menos, quando submetidas às altas temperaturas ambiente. Conclui-se que rações formuladas para frangos e galinhas não devem ser usadas na alimentação de codornas europeias e japonesas.

Effects of divergent selection for yolk testosterone content on growth characteristics of Japanese quail

Effects of yolk androgens on postnatal growth of offspring have been widely studied but their physiological role in the growth control is not fully understood due to an inconsistency in obtained results. We investigated androgen-mediated maternal effects on postnatal growth in relation to endocrine control mechanisms using two lines of Japanese quail divergently selected for high (HET) and low (LET) egg testosterone (T) content. Embryonic growth did not differ between the lines. During the growth period HET quail were heavier and displayed longer tarsi as compared with LET quail, with more pronounced line differences in males than females. HET males were heavier than LET males from the age of 2 weeks, reached the age of maximum growth rate earlier, and displayed higher asymptotic body weight than LET males. Accelerated growth in HET males was not accompanied by increased postembryonic plasma T concentrations. Plasma triiodothyronine levels did not differ between lines while plasma thyroxine levels were decreased in HET as compared with LET female chicks. Line differences in body weight disappeared in adult quail suggesting that yolk androgens, increased in a physiological way, resulted in stimulation of juvenile growth rate in precocial Japanese quail under stable social and environmental conditions.

A unified approach to the Richards-model family for use in growth analyses: why we need only two model forms

This paper advances a unified approach to the modeling of sigmoid organismal growth. There are numerous studies on growth, and there have been several proposals and applications of candidate models. Still, a lack of interpretation of the parameter values persists and, consequently, differences in growth patterns have riddled this field. A candidate regression model as a tool should be able to assess and compare growth-curve shapes, systematically and precisely. The Richards models constitute a useful family of growth models that amongst a multitude of parameterizations, re-parameterizations and special cases, include familiar models such as the negative exponential, the logistic, the Bertalanffy and the Gompertz. We have reviewed and systemized this family of models. We demonstrate that two specific parameterizations (or re-parameterizations) of the Richards model are able to substitute, and thus to unify all other forms and models. This unified-Richards model (with its two forms) constitutes a powerful tool for an interpretation of important characteristics of observed growth patterns, namely, [I] maximum (relative) growth rate (i.e., slope at inflection), [II] age at maximum growth rate (i.e., time at inflection), [III] relative mass or length at maximum growth rate (i.e., relative value at an inflection), [IV] value at age zero (i.e., birth, hatching or germination), and [V] asymptotic value (i.e., adult weight or length). These five parameters can characterize uniquely any sigmoid-growth data. To date most studies only compare what is referred to as the "growth-rate constant" or simply "growth rate" (k). This parameter can be interpreted as neither relative nor actual growth rate, but only as a parameter that affects the slope at inflection. We fitted the unified-Richards and five other candidate models to six artificial data sets, generated from the same models, and made a comparison based on the corrected Akaike's Information Criterion (AICc). The outcome may in part be the result of the random generation of data points. Still, in conclusion, the unified-Richards model performed consistently well for all data sets, despite the penalty imposed by the AICc.

Modeling growth characteristics of meat-type guinea fowl

This study was conducted to describe the growth pattern of the French guinea fowl, a meat-type variety. Using BW data from hatch to 9 wk, 2 nonlinear mathematical functions (Gompertz and logistic) were used to estimate growth patterns of the French guinea fowl. The French guinea fowl did not exhibit sexual dimorphism for growth characteristics. From the Gompertz model, the asymptotic BW, growth rate, and age at maximum growth were 2.05 kg, 0.25 kg/wk, and 5.74 wk in males, respectively, and 2.03 kg, 0.25 kg/wk, and 5.72 wk in females, respectively. The ages at maximum growth were 5.75 and 5.74 wk for males and females, respectively, using the logistic model. Differences in asymptotic BW between males and females were not significant in both Gompertz and logistic models. However, the average asymptotic BW of about 1.50 kg for both sexes predicted by the logistic model was below the average predicted BW from the Gompertz model (2.04 kg) at 9 wk. Also, the logistic model overestimated hatching weight (0.06 kg) more than the Gompertz model (0.03 kg), suggesting that the growth pattern of the French guinea fowl is Gompertz. The inverse relationship between the asymptotic weight and age at maximum growth of the French guinea fowl is similar to that of the pearl gray guinea fowl, chickens, quail, and ducks. Understanding the growth characteristics of French guinea fowl will contribute to the efforts of improving production efficiency of this least studied avian species.

Genetic Parameters from Univariate and Bivariate Analyses of Egg and Weight Traits in Japanese Quail

Fully pedigreed records of a Japanese quail population were analyzed for genetic parameters of egg and BW traits. A restricted maximum likelihood (REML) procedure was applied in univariate and bivariate analyses. Quantitative genetic analyses, including maternal effects, were carried out on the records of 947 male and 861 female birds (total = 1,808). The traits were analyzed with bird as a random factor to fit the additive direct effect, bird being the individual for which the trait was recorded, namely hen (dam) for egg traits and chick (progeny) for BW. Permanent environmental effects (0.29 to 0.35) on egg traits were higher than corresponding heritabilities (0.18 to 0.25). Significant maternal genetic and maternal permanent effects were measured for hatching BW. The heritabilities of weekly BW were low, and decreasing by 5 to 6 wk of age. They were 0.07, 0.18, 0.19, 0.18, 0.19, 0.13, and 0.15 from hatching to 6 wk, respectively. Strong correlations were detected between direct genetic effects for egg traits and maternal genetic effect for BW traits. Applying such detailed analyses in the study of both egg and BW traits provides procedures to specifically evaluate Japanese quail and poultry in general. The results illustrated that the maternal permanent environmental effects made larger contributions to the variability of egg traits than did direct genetic effects. This situation implies that rearing of birds, healthcare, and feeding are very important determinants of egg characteristics.

Growth Characteristics of Pearl Gray Guinea Fowl as Predicted by the Richards, Gompertz, and Logistic Models

This study was undertaken to describe the growth pattern of the pearl gray Guinea fowl. Using BW data from hatch to 22 wk, 3 nonlinear mathematical functions (Richards, Gompertz, and logistic) were used to estimate growth patterns of the pearl gray guinea fowl. The logistic and Gompertz models are a special case of the Richards model, which has a variable point of inflection defined by the shape or growth trajectory parameter, m. The shape parameter m was 1.08 and 0.98 in males and females, respectively, suggesting that the growth pattern of the pearl gray female guinea fowl is Gompertz. The pearl gray guinea fowl exhibited sexual dimorphism for their growth characteristics. From the Gompertz model, the asymptotic BW, growth rate, and age at maximum growth were 1.62 kg, 0.22 kg/wk, and 6.65 wk in males, respectively, and 1.70 kg, 0.19 kg/wk, and 6.70 wk in females, respectively. The ages at maximum growth were 6.65, 6.47, and 8.12 wk for the Richards, Gompertz, and logistic models, respectively. The pearl gray guinea fowl females have a higher asymptotic BW compared with the males. The average asymptotic BW of about 1.57 kg for both sexes predicted by the logistic model was below the average predicted BW from the Richards (1.66 kg) and Gompertz (1.67 kg) models, respectively, at 22 wk of age. The inverse relationship between the asymptotic weight and both relative growth and age at maximum growth of the pearl gray guinea fowl is similar to that of chickens, quail, and ducks. Success in studying the growth characteristics of guinea fowl will contribute to the efforts of genetically improving this least-studied avian species.