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Early growth traits in quails are considered as the growth performances before the inflection point which are genetically different from body weights (BW) at later stages. Moreover, in addition to growth performance, humoral immunity is moderately heritable and is considered in some breeding programs. However, estimating the direct genetic, particularly the maternal genetic correlations between growth and immunity in quail, are not studied sufficiently, which were the aims of the present study. The quails' BW were recorded at hatch (BW0) to 25 d of age with a 5-d interval and body weight gains (BWG) were measured as average growth performance of the birds in a 5-d period. Antibody titer against Newcastle disease virus (IgN) was measured through the hemagglutination inhibition (HI) test. For titration of anti-SRBC antibodies (IgY and IgM), a hemagglutination microtiter assay was used. In general, growth records in 4,181 birds and humoral immune responses in 1,023 birds were assigned to the study. The genetic parameters were estimated by single-trait analysis via Gibb's sampling. After finding the best model for each trait, multi-trait analysis was done to estimate the direct and maternal genetic correlations. Direct heritabilities (h 2 ) were estimated to be moderate for BW (0.481-0.551) and BWG (0.524-0.557), while h 2 for immune responses were low (0.035-0.079). Maternal environmental effect (c 2 ) was only significant for BW0, BW5, and BWG0-5. Maternal heritabilities (m 2 ) for BW and BWG were all lower than corresponding h 2 , ranging from 0.072 (BW25) to 0.098 (BW0). The m 2 for IgN (0.098) was more than 2.5 times greater than h 2 (0.040) for this trait. Direct (r a ) and maternal (r m ) genetic correlations between IgN-BW, IgY-BW, and IgY-BWG were negative, while ra and rm for IgM-BW, IgN-BWG, and IgM-BWG were positive. The r a between humoral immune responses were low to moderate and rm was significant only for IgY-IgM (0.339). Given positive genetic correlations in BWG-IgN and BWG-IgM as well as positive genetic correlations between both IgN and IgM with IgY, it is suggested that including the BWG in the breeding programs would directly result in the improvement of the birds' growth performance. It would also contribute indirectly to the improvement of the birds' humoral immune responses., (Copyright © 2022. Published by Elsevier Inc.)

Minimizing bird mortality in the commercial quail breeding industry is important from an economic and welfare perspective. Genetic and non-genetic factors can influence on the cumulative survival of the birds (CS). Accordingly, this study aimed to investigate non-genetic factors on CSs (cumulative survival of the birds from hatch to 5 (CS 1 ), 10 (CS 2 ), 15 (CS 3 ), 20 (CS 4 ), 25 (CS 5 ), 30 (CS 6 ), 35 (CS 7 ), 40 (CS 8 ), and 45 (CS 9 ) days of age), and estimation of the genetic parameters for CSs in crossbred population of quail. Data set included 1794 records from crossbred chicks hatched from 70 sires and 72 dams. The fixed effects were analyzed using an animal model by ASReml software, and all traits were analyzed using Bayesian method via Gibbs sampling by fitting of 6 threshold animal models including the direct genetic effect, the maternal permanent environmental effect, and the maternal genetic effect. The best fitted model for each trait was selected based on the deviance information criteria. Hatch number, the month of hatch, and combination of chickens showed a significant effect on CSs, but the sex of chickens does not have a significant effect on CSs. However, females have higher survival than males (except for CS 1 ). With the best model, the highest and lowest direct heritability was estimated for CS 5 (0.386) and CS 3 (0.250), respectively. The maternal genetic effect was significant for CS 1 , CS 2 , CS 3 , and CS 4 traits, but the maternal permanent environmental effect was significant only for CS 1 . The range of maternal heritability for CS 1 to CS 4 traits was estimated from 0.064 to 0.111, and ratio of the permanent environmental variance to phenotypic variance for CS 1 was 0.021. The result showed that increasing of the birds' survival could be performed by correcting non-genetic factors and genetic selection for CSs considering the maternal genetic effects in younger ages. HIGHLIGHTS: • In the commercial quail breeding industry, the bird mortality is important from an economic and welfare perspective. • Improving quail survival can be achieved by controlling the genetic and non-genetic factors affecting on survival, so knowledge of these factors is necessary. • The combination of crossbred chickens had a significant effect on cumulative survival traits. • The Cumulative survival traits in the crossbred population had relatively high genetic diversity, so genetic selection for these traits could be effective., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Lysozyme activity is one of the nonspecific immunity parameters measured by changing the amount of adsorption at different times. The objective of the present study was to compare five non-linear models including Gompertz, Richards, Logistic, Lopez, and Weilbull to describe the cumulative plasma lysozyme activity in quails. In total 1364 plasma samples (1004 females and 360 males) were collected and the cumulative lysozyme activity was calculated by turbidimetric method assay in Micrococcus luteus. The goodness-of-fit of models was compared according to different criteria of Maximum loglikelihood, Akaike information criterion, Mean square error, and Bayesian information criterion. The results showed that the Gompertz model was the best model for describing of decreasing cumulative pattern of lysozyme activity in female and male quails and provided satisfactory predictions of lysozyme activity at different times (30, 60, 90, 120, 150, 180, 210, 240, 270, 300 seconds). The parameters of all models were higher in females than males except for the k parameter which was greater in the males. Male quails had higher values for time and lysozyme activity than females at inflection points, whereas the absolute growth rate in 30, 150, and 300 seconds was predicted higher in female quails. In conclusion, the Gompertz model can be used accurately to evaluate cumulative lysozyme activity patterns in both sexes of quails. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the growth pattern of seven strains of Japanese quail including Wild, Italian Speckled, Tuxedo, Scarlett, English white, White button, and A&M Texas by nonlinear growth functions including Gompertz, Richards, logistic, Lopez, and Weibull functions. The body weights of the unselected randomly bred populations of these strains were measured weekly from 1 to 42 days of age and then used to fit functions. The fitness of each function was assessed by statistics including the mean square error, Akaike information criterion, Bayesian information criterion, and adjusted coefficient of determination. The results showed that Gompertz was the best function for describing the growth curve in Italian Speckled and Wild strains; however, the best function for the other strains was the logistic function. The maximum and minimum values for age and weight at the inflection point were obtained for the White button and Scarlett strains, respectively. The weight to age ratio at the inflection point was maximized for Italian Speckled. The best growth rate was observed for the Italian Speckled strain, whereas the White button strain exhibited the worst growth rate. In conclusion, the Italian Speckled strain had the best properties among the tested strains for breeding as broiler poultry. [ABSTRACT FROM AUTHOR]