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

^{1}

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## Abstract

**:**

## Simple Summary

_{0}parameter of the growth curve might be beneficial in selection studies.

## Abstract

## 1. Introduction

## 2. Materials and Methods

^{2}/quail) for the first three weeks (each chick was raised in divided cages for a period of 21 days.); following sex determination in the third week, they were transferred to individual fattening cages (160 cm

^{2}/quail) where they remained until the age of 42 days. At 21 days of age, the presence (for females) or absence (for males) of speckled breast feathers was used to determine the gender of birds. A grower diet with 24% crude protein and 2900 kcal of metabolizable energy/kg/kg was employed for the first 21 days, followed by a fattening diet with 23% crude protein and 2800 kcal of metabolizable energy/kg. From hatching until the end of the trial, ad libitum feeding, water, and a 23 h per day lighting schedule were utilized.

**β**is a vector of fixed effects, and

**u**is a vector of random genetic effects.

**X**and

**Z**are known design matrices relating phenotypic records to $\mathsf{\beta}$ and

**u**, respectively.

**e**is a vector of random errors. It is further specified that covariance matrix is equal to $\mathbf{R}={\mathbf{R}}_{0}\otimes \mathbf{I}$, where

**I**represent the identity matrix and denotes genetic covariance matrix, while the matrix $\mathbf{G}$ is equal to $\mathbf{G}={\mathbf{G}}_{0}\otimes \mathbf{A}$, where

**A**is the numerator relationship matrix.

**y**and prior distributions of $\mathsf{\beta}$ and $\mathbf{a}$ should be defined, as well as variance-covariance components ${\mathbf{G}}_{0},{\mathbf{R}}_{0}$.

**β,**which is a vector of fixed effects. The prior distribution assumed for ${\mathbf{G}}_{0}$ and ${\mathbf{R}}_{0}$ was an Inverse Wishart distribution which is conjugate to multivariate normal distribution [21].

## 3. Results

#### 3.1. Basic Statistics

_{0}, β

_{1}, β

_{2}, IPT, and IPW are presented in Table 1. At 5 and 6 weeks of age, females had greater mean body weight and cumulative feed intake values than males (all p < 0.05). At 5 and 6 weeks of age, the mean body weights of male quails were 181.88 g and 201.57 g, while the mean body weights of female quails were 191.78 g and 211.16 g, respectively. At 5 weeks of age, the average cumulative feed intake value for male quails was 431.45 g, whereas the average for female quails was 470.98 g. Similarly, the average cumulative feed intakes of male and female quails at 6 weeks of age were 595.88 g and 652.74 g, respectively. There were no statistical differences between the average cumulative feed conversion efficiencies of female and male quails at 5 and 6 weeks of age (both p > 0.05). At 6 weeks old, male and female quails had mean cumulative feed conversion ratios (1/FCE) of 2.46 and 2.43, respectively; at 6 weeks old, these averages had increased to 3.01 and 3.08, respectively.

^{2}) in the range of 0.9978 to 0.9999 were found. In terms of the distant asymptotic weight parameter (β

_{0}) of the Gompertz function, a statistically significant difference was found between male and female quails (p < 0.05). While the average β

_{0}parameter of males was found to be 235.94 g, the mean value of the β

_{0}parameter of females was estimated to be 260.01 g. Males and females did not differ statistically in terms of the scaling parameter and the instantaneous growth rate parameter of the Gompertz model (both p > 0.05). The mean values of β

_{1}and β

_{2}for male quails were estimated to be 3.29 and 0.068, while those for females were 3.32 and 0.071. Statistical differences were identified between genders in terms of inflection point coordinates of the Gompertz model (p > 0.05). The estimated age of inflection is younger for females (16.90 days) than for males (18.51 days). Likewise, the average inflection point weight of female quails (95.65) was found to be greater than that of males (86.81 g).

#### 3.2. Heritability Estimates

_{1}, β

_{2}, and IPW characteristics. Heritability estimates for FI5, FCE5, β

_{0}, and IPT traits were moderate to high (0.36–0.37). In addition, estimations of the heritability of FI6 and FCE6 characteristics (respectively, 0.23 and 0.26) ranged from low to moderate.

#### 3.3. Genetic and Phenotypic Relationships

_{0}/e and IPT = ln(β

_{1})/β

_{2}), there are fixed relationships between parameter β

_{0}and IPW and between IPT and parameters β

_{1}and β

_{2}. Although the β

_{0}parameter of the Gompertz model exhibited strong genetic and phenotypic relationships with BW5 and BW6 (0.52–0.82), no significant correlations were observed with feed efficiency characteristics. The phenotypic and genetic relationships between parameters β

_{1}and β

_{2}of the Gompertz model with body weight and feed efficiency characteristics were weak and statistically insignificant (ranging from −0.19 to 0.20).

## 4. Discussion

_{0}parameter (249.91 g) was in agreement with the mean values reported by Beiki et al. [32] and Narinç et al. [13]. Similarly, the mean values for the β

_{0}parameter of the Gompertz function in Japanese quails were estimated in the range of 242–276 g by Karabağ et al. and Hyankova et al. [14,33]. The integration coefficient parameter (β

_{1}) of the Gompertz model for the growth of Japanese quail was estimated by Akbaş and Yaylak [10] and Narinc et al. [31] to be 3.39 and 3.31, respectively, which is consistent with the mean value (3.31) in our study. The estimated mean values for the β2 parameter and inflection point coordinates of the growth model are consistent with the results of a number of studies [9,19,27,28] employing the Gompertz growth model in Japanese quails.

_{0}parameter of the growth model [14] and inflection point coordinates [20].

_{0}parameter. In addition, there are researchers who find the estimates of heritability for the β

_{0}parameter to be both lower (0.17) [38] and higher (0.54) [41]. The high heritability estimates for the β

_{1}and β

_{1}parameters of the Gompertz model in this study are consistent with the findings of Saghi and Saghi [42] and Narinc et al. [13]. Various researchers have reported varying heritability estimates for the inflection point age of the Gompertz model in Japanese quails. Some researchers [14,18,31] have claimed that the heritability estimates of the IPT trait are low (0.08–0.21). The estimated heritability for the IPT trait in this study is comparable to moderate to high estimates (0.23–0.41) reported by Akbaş and Yaylak [10]. Because of the fact that the inflection point weight of the Gompertz growth model is obtained by dividing the β

_{0}parameter by number e, all the variance components are equal to the β

_{0}parameter. Due to the nature of the Bayesian estimator (Gibbs sampler) utilized in this study, only small iteration-related differences between the variance component estimates of β

_{0}and IPW occurred.

_{0}parameter of the Gompertz growth model. Nevertheless, the genetic correlations (0.28 and 0.34) between β

_{0}and FCE characteristics were relatively weaker than those between FCE and BW (ranging from 0.52 to 0.82).

## 5. Conclusions

_{0}parameter of the Gompertz growth model and the FCE traits, it has been determined that the β

_{0}parameter can be used as an alternative in case the additive genetic variance for live weight decreases in the following generations of selection.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

- Emmerson, D. Breeding objectives and selection strategies for broiler production. In Poultry Breeding, Genetics and Biotechnology; CAB International: Wallingford, UK, 2003; pp. 113–126. [Google Scholar]
- Tixier-Boichard, M.; Leenstra, F.; Flock, D.K.; Hocking, P.M.; Weigend, S. A century of poultry genetics. Worlds Poult. Sci. J.
**2012**, 68, 307–321. [Google Scholar] [CrossRef] - Narinc, D.; Aksoy, T.; Kaplan, S. Effects of multi-trait selection on phenotypic and genetic changes in Japanese quail (Coturnix coturnix japonica). J. Poult. Sci.
**2016**, 53, 103–110. [Google Scholar] [CrossRef] - Wolc, A. Understanding genomic selection in poultry breeding. Worlds Poult. Sci. J.
**2014**, 70, 309–314. [Google Scholar] [CrossRef] - Wolc, A.; Kranis, A.; Arango, J.; Settar, P.; Fulton, J.E.; O’Sullivan, N.P.; Avendano, A.; Watson, K.A.; Hickey, J.M.; de los Campos, G.; et al. Implementation of genomic selection in the poultry industry. Anim. Front.
**2016**, 6, 23–31. [Google Scholar] [CrossRef] - Marks, H.L. Long-term selection for body weight in Japanese quail under different environments. Poult. Sci.
**1996**, 75, 1198–1203. [Google Scholar] [CrossRef] - Minvielle, F.; Monvoisin, J.L.; Costa, J.; Maeda, Y. Long-term egg production and heterosis in quail lines after within-line or reciprocal recurrent selection for high early egg production. Br. Poult. Sci.
**2000**, 41, 150–157. [Google Scholar] [CrossRef] - Varkoohi, S.; Babak, M.M.S.; Pakdel, A.; Javaremi, A.N.; Zaghari, M.; Kause, A. Response to selection for feed conversion ratio in Japanese quail. Poult. Sci.
**2010**, 89, 1590–1598. [Google Scholar] [CrossRef] - Minvielle, F. What are quail good for in a chicken-focused world? World’s Poult. Sci. J.
**2009**, 65, 601–608. [Google Scholar] [CrossRef] - Akbas, Y.; Yaylak, E. Heritability estimates of growth curve parameters and genetic correlations between the growth curve parameters and weights at different age of Japanese quail. Arch. Geflugelkd.
**2000**, 64, 141–146. [Google Scholar] - Aksit, M.; Oguz, I.; Akbas, Y.; Altan, Ö.; Özdoğan, M. Genetic variation of feed traits and relationships to some meat production traits in Japanese quail (Coturnix cot. japonica). Arch. Geflugelkd.
**2003**, 67, 76–82. [Google Scholar] - Narinc, D.; Aksoy, T.; Karaman, E.; Aygun, A.; Firat, M.Z.; Uslu, M.K. Japanese quail meat quality: Characteristics, heritabilities, and genetic correlations with some slaughter traits. Poult. Sci.
**2013**, 92, 1735–1744. [Google Scholar] [CrossRef] - Narinc, D.; Karaman, E.; Aksoy, T.; Firat, M.Z. Genetic parameter estimates of growth curve and reproduction traits in Japanese quail. Poult. Sci.
**2014**, 93, 24–30. [Google Scholar] [CrossRef] - Karabag, K.; Alkan, S.; Karsli, T.; Balcioglu, M.S. Genetic changes in growth curve parameters in Japanese quail lines divergently selected for body weight. Eur. Poult. Sci.
**2017**, 81, 10. [Google Scholar] [CrossRef] - Prakash, A.; Saxena, V.K.; Singh, M.K. Genetic analysis of residual feed intake, feed conversion ratio and related growth parameters in broiler chicken: A review. Worlds Poult. Sci. J.
**2020**, 76, 304–317. [Google Scholar] [CrossRef] - Skinner-Noble, D.; McKinney, L.; Teeter, R. Predicting effective caloric value of nonnutritive factors: III. Feed form affects broiler performance by modifying behavior patterns. Poult. Sci.
**2005**, 84, 403–411. [Google Scholar] [CrossRef] - Dransfield, E.; Sosnicki, A. Relationship between muscle growth and poultry meat quality. Poult. Sci.
**1999**, 78, 743–746. [Google Scholar] [CrossRef] - Narinc, D.; Karaman, E.; Firat, M.Z.; Aksoy, T. Comparison of non-linear growth models to describe the growth in Japanese quail. J. Anim. Vet. Adv.
**2010**, 9, 1961–1966. [Google Scholar] [CrossRef] - Akbas, Y.; Oguz, I. Growth curve parameters of lines of Japanese quail (Coturnix coturnix japonica), unselected and selected for four-week body weight. Arch. Fuer Gefluegelkunde
**1998**, 62, 104–109. [Google Scholar] - Balcıoğlu, M.; Kızılkaya, K.; Yolcu, H.; Karabağ, K. Analysis of growth characteristics in short-term divergently selected Japanese quail. S. Afr. J. Anim. Sci.
**2005**, 35, 83–89. [Google Scholar] - Zhang, Z. A note on wishart and inverse wishart priors for covariance matrix. J. Behav. Data Sci.
**2021**, 1, 119–126. [Google Scholar] [CrossRef] - Hadfield, J.D. MCMC methods for multi-response generalized linear mixed models: The MCMCglmm R package. J. Stat. Softw.
**2010**, 33, 1–22. [Google Scholar] [CrossRef] - Alkan, S.; Karabag, K.; Galic, A.; Karsli, T.; Balcioglu, M.S. Determination of body weight and some carcass traits in Japanese quails (Coturnix coturnix japonica) of different lines. Kafkas Univ. Vet. Fak. Derg.
**2010**, 16, 277–280. [Google Scholar] - Foomani, N.N.; Zerehdaran, S.; Azari, M.A.; Lotfi, E. Genetic parameters for feed efficiency and body weight traits in Japanese quail. Br. Poult. Sci.
**2014**, 55, 298–304. [Google Scholar] [CrossRef] [PubMed] - Mahmoud, B.Y.; Hafez, A.S.A.; Emam, A.M.; Abdelmoniem, A.M.; ElSafty, S.A. Feathering rate impact on growth and slaughter traits of Japanese quail. J. Agric. Sci.
**2018**, 156, 942–948. [Google Scholar] [CrossRef] - Fathi, M.M.; Al-Homidan, I.; Ebeid, T.A.; Galal, A.; Abou-Emera, O.K. Assessment of residual feed intake and its relevant measurements in two varieties of Japanese quails (Coturnixcoturnix japonica) under high environmental temperature. Animals
**2019**, 9, 299. [Google Scholar] [CrossRef] [PubMed] - Lotfi, E.; Zerehdaran, S.; Azari, M.A. Genetic evaluation of carcass composition and fat deposition in Japanese quail. Poult. Sci.
**2011**, 90, 2202–2208. [Google Scholar] [CrossRef] - Karaman, E.; Firat, M.Z.; Narinc, D. Single-trait Bayesian analysis of some growth traits in Japanese quail. Braz. J. Poult. Sci.
**2014**, 16, 51–56. [Google Scholar] [CrossRef] - Shafik, B.M.; Kamel, E.R.; Mamdouh, M.; Elrafaay, S.; Nassan, M.A.; El-Bahy, S.M.; El-Tarabany, M.S.; Manaa, E.A. Performance, blood lipid profile, and the expression of growth hormone receptor (GHR) and insulin-like growth factor-1 (IGF-1) genes in purebred and crossbred quail lines. Animals
**2022**, 12, 1245. [Google Scholar] [CrossRef] - Altan, O.; Oguz, I.; Akbas, Y.; Aksit, M. Genetic variability of residual feed consumption (RFC) and its relationships with some production traits and fear response in Japanese quail hens (Cotumix cot. japonica). Arch. Geflugelkd.
**2004**, 68, 223–229. [Google Scholar] - Narinc, D.; Aksoy, T.; Karaman, E. Genetic parameters of growth curve parameters and weekly body weights in Japanese quails (Coturnix coturnix japonica). J. Anim. Vet. Adv.
**2010**, 9, 501–507. [Google Scholar] [CrossRef] - Beiki, H.; Pakdel, A.; Moradi-Shahrbabak, M.; Mehrban, H. Evaluation of growth functions on Japanese quail lines. J. Poult. Sci.
**2013**, 50, 20–27. [Google Scholar] [CrossRef] - Hyankova, L.; Knížetová, H.; Dědková, L.; Hort, J. Divergent selection for shape of growth curve in Japanese quail. 1. Responses in growth parameters and food conversion. Br. Poult. Sci.
**2001**, 42, 583–589. [Google Scholar] [CrossRef] - Aggrey, S.E.; Karnuah, A.B.; Sebastian, B.; Anthony, N.B. Genetic properties of feed efficiency parameters in meat-type chickens. Genet. Sel. Evol.
**2010**, 42, 25. [Google Scholar] [CrossRef] - Vali, N.; Edriss, M.; Rahmani, H. Genetic parameters of body and some carcass traits in two quail strains. Int. J. Poult. Sci.
**2005**, 4, 296–300. [Google Scholar] - Narinç, D.; Aksoy, T. Effects of mass selection based on phenotype and early feed restriction on the performance and carcass characteristics in Japanese quails. Kafkas Univ. Vet. Fak. Derg.
**2012**, 18, 425–430. [Google Scholar] - Waldmann, P.; Ericsson, T. Comparison of REML and Gibbs sampling estimates of multi-trait genetic parameters in Scots pine. Theor. Appl. Genet.
**2006**, 112, 1441–1451. [Google Scholar] [CrossRef] - Narinc, D.; Aydemir, E. Genetic parameter estimates of chick quality, growth, and carcass characteristics in Japanese quail. J. Hell. Vet. Med. Soc.
**2021**, 72, 3363–3370. [Google Scholar] [CrossRef] - Taroco, G.; Gaya, L.G.; Mota, L.F.M.; Souza, K.A.R.; Lima, H.J.D.; Silva, M.A. Heritability and genotype-environment interactions for growth curve parameters in meat-type quail fed different threonine:lysine ratios from hatching to 21 d of age. Poult. Sci.
**2019**, 98, 69–73. [Google Scholar] [CrossRef] - Caetano, G.D.; Mota, R.R.; da Silva, D.A.; de Oliveira, H.R.; Viana, J.M.S.; de Siqueira, O.; Freitas, P.H.F.; Silva, F.F.E. Bayesian estimation of genetic parameters for individual feed conversion and body weight gain in meat quail. Livest. Sci.
**2017**, 200, 76–79. [Google Scholar] [CrossRef] - Mignon-Grasteau, S.; Piles, M.; Varona, L.; De Rochambeau, H.; Poivey, J.; Blasco, A.; Beaumont, C. Genetic analysis of growth curve parameters for male and female chickens resulting from selection on shape of growth curve. J. Anim. Sci.
**2000**, 78, 2515–2524. [Google Scholar] [CrossRef] - Saghi, R.; Saghi, D. Estimation of heritability, phenotypic and genetic correlations for growth curve characteristics of Japanese quail. J. Anim. Sci. Res.
**2022**, 31, 113–126. [Google Scholar] - Akbas, Y.; Takma, C.; Yaylak, E. Genetic parameters for quail body weights using a random regression model. S. Afr. J. Anim. Sci.
**2004**, 34, 104–109. [Google Scholar] [CrossRef] - Alkan, S.; Karslı, T.; Galiç, A.; Karabağ, K.; Balcıoğlu, M. Japon bıldırcınlarında (Coturnix coturnix japonica) canlı ağırlığa ait genetik parametrelerin şansa bağlı regresyon modeli kullanılarak tahmin edilmesi. Kafkas Univ. Vet. Fak. Derg.
**2012**, 18, 935–939. [Google Scholar] - Kaplan, S.; Narinc, D.; Gurcan, E.K. Genetic parameter estimates of weekly body weight and Richard’s growth curve in Japanese quail. Eur. Poult. Sci.
**2016**, 80, 10. [Google Scholar] [CrossRef] - Pakdel, A.; Van Arendonk, J.A.M.; Vereijken, A.L.J.; Bovenhuis, H. Genetic parameters of ascites-related traits in broilers: Correlations with feed efficiency and carcase traits. Br. Poult. Sci.
**2005**, 46, 43–53. [Google Scholar] [CrossRef] - Chambers, J.R.; Lin, C.Y. Age-constant versus weight-constant feed consumptions and efficiency in broiler-chickens. Poult. Sci.
**1988**, 67, 565–576. [Google Scholar] [CrossRef] - Koerhuis, A.; Hill, W. Predicted response in food conversion ratio for growth by selection on the ratio or on linear component traits, in a (sequential) selection programme. Br. Poult. Sci.
**1996**, 37, 317–327. [Google Scholar] [CrossRef]

Trait | Mean | Standard Deviation | Coefficient of Variance (%) | Minimum | Maximum | Sex Effect ^{2} |
---|---|---|---|---|---|---|

BW5 | 185.84 | 19.23 | 10.35 | 134.89 | 242.90 | 0.001 |

BW6 | 204.54 | 20.48 | 10.01 | 150.22 | 277.83 | 0.001 |

FI5 | 449.77 | 51.89 | 11.54 | 291.59 | 614.51 | 0.001 |

FI6 | 621.48 | 77.74 | 12.51 | 354.52 | 822.28 | 0.001 |

FCE5 | 0.409 | 0.0576 | 14.09 | 0.254 | 0.608 | 0.078 |

FCE6 | 0.328 | 0.0507 | 15.44 | 0.211 | 0.466 | 0.126 |

β_{0} | 249.91 | 36.64 | 14.66 | 171.08 | 338.44 | 0.003 |

β_{1} | 3.31 | 0.23 | 6.84 | 2.77 | 3.99 | 0.125 |

β_{2} | 0.069 | 0.010 | 13.89 | 0.040 | 0.096 | 0.245 |

IPT | 17.60 | 2.58 | 14.68 | 12.01 | 31.61 | 0.001 |

IPW | 91.94 | 13.48 | 14.66 | 62.94 | 124.50 | 0.003 |

^{1}BW5–6 = Body weights at 5 and 6 weeks of age; FI5–6 = Cumulative feed intakes at 5 and 6 weeks of age; FCE5–6 = Cumulative feed conversion efficiencies at 5 and 6 weeks of age; β

_{0}= Asymptotic body weight parameter; β

_{1}= Shape parameter; β

_{2}= Instantaneous growth rate parameter; IPT = Time at the inflection point of growth curve; and IPW = Body weight at the inflection point of the growth curve.

^{2}The p values of the Independent Sample t-test were evaluated at a significant level of 0.05.

**Table 2.**Posterior expectations, SD, credible intervals, and highest posterior density intervals of the heritability estimates.

Trait ^{1} | Mean | Median | SD ^{2} | MCSE ^{3} | BCI ^{4}2.5 | BCI 97.5 | HPDI ^{5}2.5 | HPDI 97.5 |
---|---|---|---|---|---|---|---|---|

BW5 | 0.59 | 0.57 | 0.11 | 0.001 | 0.45 | 0.73 | 0.46 | 0.73 |

BW6 | 0.61 | 0.60 | 0.11 | 0.001 | 0.48 | 0.75 | 0.47 | 0.75 |

FI5 | 0.36 | 0.35 | 0.09 | 0.001 | 0.26 | 0.48 | 0.27 | 0.49 |

FI6 | 0.23 | 0.23 | 0.05 | 0.001 | 0.11 | 0.32 | 0.12 | 0.35 |

FCE5 | 0.37 | 0.37 | 0.02 | 0.001 | 0.25 | 0.49 | 0.29 | 0.51 |

FCE6 | 0.26 | 0.26 | 0.05 | 0.002 | 0.14 | 0.38 | 0.18 | 0.37 |

β_{0} | 0.37 | 0.36 | 0.10 | 0.001 | 0.25 | 0.49 | 0.28 | 0.51 |

β_{1} | 0.43 | 0.43 | 0.07 | 0.001 | 0.31 | 0.55 | 0.33 | 0.55 |

β_{2} | 0.47 | 0.47 | 0.06 | 0.001 | 0.36 | 0.58 | 0.36 | 0.61 |

IPT | 0.37 | 0.37 | 0.02 | 0.001 | 0.27 | 0.50 | 0.26 | 0.49 |

IPW | 0.38 | 0.37 | 0.10 | 0.001 | 0.27 | 0.48 | 0.29 | 0.50 |

^{1}BW5–6 = Body weights at 5 and 6 weeks of age; FI5–6 = Cumulative feed intakes at 5 and 6 weeks of age; FCE5–6 = Cumulative feed conversion efficiencies at 5 and 6 weeks of age; β

_{0}= Asymptotic body weight parameter; β

_{1}= Shape parameter; β

_{2}= Instantaneous growth rate parameter; IPT = Time at the inflection point of growth curve; and IPW = Body weight at the inflection point of the growth curve.

^{2}The p values of the Independent Sample t-test were evaluated at a significance level of 0.05. SD = Standard deviation.

^{3}MCSE = Monte Carlo Standard errors,

^{4}BCI = Bayesian credible interval (2.5%, lower bound; 97.5%, upper bound).

^{5}HPDI = Highest posterior density interval (2.5%, lower bound; 97.5%, upper bound).

**Table 3.**The genetic correlation estimates (below diagonal) and phenotypic correlations (above diagonal) for growth and feed efficiency traits

^{1}.

BW5 | BW6 | FI5 | FI6 | FCE5 | FCE6 | β_{0} | β_{1} | β_{2} | IPT | IPW | |
---|---|---|---|---|---|---|---|---|---|---|---|

BW5 | 0.90 * | 0.40 * | 0.33 * | 0.67 * | 0.49 * | 0.52 * | −0.11 | −0.13 | 0.18 | 0.53 * | |

BW6 | 0.92 (0.01) ^{2} | 0.28 * | 0.43 * | 0.59 * | 0.75 * | 0.76 * | −0.09 | −0.18 | 0.12 | 0.75 * | |

FI5 | 0.49 (0.01) | 0.34 (0.01) | 0.68 * | −0.49 * | −0.29 * | 0.08 | −0.02 | −0.02 | 0.08 | 0.09 | |

FI6 | 0.35 (0.11) | 0.48 (0.01) | 0.75 (0.07) | −0.29 * | −0.44 * | 0.09 | −0.01 | −0.01 | 0.10 | 0.08 | |

FCE5 | 0.71 (0.07) | 0.61 (0.08) | −0.53 (0.08) | −0.32 (0.05) | 0.78 * | 0.29 * | 0.19 | −0.09 | 0.15 | 0.29 | |

FCE6 | 0.52 (0.05) | 0.83 (0.03) | −0.45 (0.03) | −0.58 (0.02) | 0.83 (0.06) | 0.27 * | 0.06 | −0.23 | 0.11 | 0.28 | |

β_{0} | 0.58 (0.01) | 0.82 (0.01) | 0.16 (0.05) | 0.12 (0.06) | 0.34 (0.08) | 0.28 (0.02) | −0.34 * | −0.64 * | 0.66 * | 0.99 * | |

β_{1} | −0.17 (0.02) | −0.17 (0.03) | 0.06 (0.05) | 0.21 (0.04) | 0.20 (0.05) | 0.12 (0.02) | −0.37 (0.01) | 0.51 * | 0.71 * | −0.34 * | |

β_{2} | −0.16 (0.02) | −0.19 (0.04) | 0.13 (0.01) | 0.11 (0.07) | 0.12 (0.06) | 0.14 (0.04) | −0.70 (0.02) | 0.66 (0.01) | −0.89 * | −0.64 * | |

IPT | 0.22 (0.04) | 0.20 (0.03) | 0.12 (0.04) | 0.14 (0.04) | 0.17 (0.01) | 0.12 (0.06) | 0.69 (0.07) | 0.79 (0.01) | −0.95 (0.01) | 0.66 * | |

IPW | 0.58 (0.01) | 0.82 (0.01) | 0.15 (0.08) | 0.22 (0.06) | 0.34 (0.03) | 0.29 (0.03) | 0.99 (0.01) | −0.36 (0.06) | −0.71 (0.01) | 0.70 (0.01) |

^{1}BW5–6 = Body weights at 5 and 6 weeks of age; FI5–6 = Cumulative feed intakes at 5 and 6 weeks of age; FCE5–6 = Cumulative feed conversion efficiencies at 5 and 6 weeks of age; β

_{0}= Asymptotic body weight parameter; β

_{1}= Shape parameter; β

_{2}= Instantaneous growth rate parameter; IPT = Time at the inflection point of growth curve; and IPW = Body weight at the inflection point of the growth curve.

^{2}The standard error of the genetic correlation estimate is in parentheses. * The phenotypic correlation was statistically significant, p < 0.05.

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**MDPI and ACS Style**

Kaya Başar, E.; Narinç, D. Genetic Parameter Estimates of Growth Curve and Feed Efficiency Traits in Japanese Quail. *Animals* **2023**, *13*, 1765.
https://doi.org/10.3390/ani13111765

**AMA Style**

Kaya Başar E, Narinç D. Genetic Parameter Estimates of Growth Curve and Feed Efficiency Traits in Japanese Quail. *Animals*. 2023; 13(11):1765.
https://doi.org/10.3390/ani13111765

**Chicago/Turabian Style**

Kaya Başar, Ebru, and Doğan Narinç. 2023. "Genetic Parameter Estimates of Growth Curve and Feed Efficiency Traits in Japanese Quail" *Animals* 13, no. 11: 1765.
https://doi.org/10.3390/ani13111765