This study aims to investigate the effect of supplementing dietary cinnamon oil (CO) into broiler chicken diets on growth performance, carcass traits, haemato-biochemical parameters, immune function, antioxidant status, and caecal microbial count. Three hundred one-day old broilers were...

The objectives of this study were to analyse the differences in the genetic determination of functional longevity in five Spanish lines of rabbits and to check how different systematic factors might affect this genetic determination. Four of the lines were maternal (lines A, V, H and LP), these lines were established selecting base generation animals according to different criteria, but in the subsequent generations all of them were selected for litter size at weaning. The other is the paternal line R, this line was constituted by selecting animals with an outstanding daily growth rate. The trait analysed, length of productive life, was the time in days between the date of the first positive pregnancy test and the date of culling or death of a doe. Four models extended from the Cox proportional hazard model were used to analyse data of each line separately and jointly. The complete model (Model 1) included the fixed effect of year-season (YS) combination, positive palpation order (OPP), that is, reproductive cycle, physiological status of the doe (PS) at service and number of kits born alive (NBA) in each kindling as time-dependent factors. The inbreeding coefficient was fitted as a continuous covariate and the animal’s additive genetic effect was also fitted to the model (Model 1). The other models were identical to Model 1 but excluding OPP (Model 2) or PS (Model 3) or NBA (Model 4), which were explored to assess the consequence on additive variance estimates of not correcting for these animal-dependent factors. Estimated effective heritabilities of longevity were 0.07 ± 0.03, 0.03 ± 0.02, 0.14 ± 0.09, 0.05 ± 0.04, 0.02 ± 0.01 and 0.04 ± 0.01 for lines A, V, H, LP, R and for the merged data set, respectively. Removing the PS from the model led to an increase in the estimated additive genetic variance in all lines (0.17 ± 0.05, 0.05 ± 0.03, 0.29 ± 0.19, 0.29 ± 0.20, 0.07 ± 0.04 and 0.05 ± 0.02 for lines A, V, H, LP, R and the merged data set, respectively). The highest hazard of death and/or culling was observed during the first two parities and decreased as the order of parity progressed. Does non-pregnant-non-lactating had the highest risk of death or culling. The does that had zero kits born alive incurred the highest risk, and this risk decreased as the NBA increased. In conclusion, the consideration of longevity as selection criterion for the studied rabbit lines is not recommended.

The objectives of the present study were 1) to evaluate the polymorphism of growth hormone(GH), insulin-like growth factor 2 (IGF2) and progesterone receptor (PGR) genes in Sinai Gabali rabbits, and 2) to assess their associations with growth, litter size and milk production traits in Sinai Gabali rabbits. The C>T, A>Del and A>G single nucleotide polymorphisms of GH, IGF2 and PGR genes were genotyped by polymerase chain reaction-restriction fragment length polymorphism using BstUI, HpyF31 and BsaI restriction enzymes, respectively. The C/T genotype of GH gene recorded the heaviest body weights for body weight (BW) at 8 wk (1190.22±19.29 g) and 12 wk of age (1842.46±30.19 g) and recorded the largest litter size at birth (LSB: 7.37±0.12 kits) traits. The Del/Del genotype of IGF2 gene showed the superiority over the other genotypes for BW at 4 wk (507.17±8.87 g), 8 wk (1239.39±14.0 g), and 12 wk of age (1950.15±18.1 g), as well as for daily weight gain from 4 to 8 wk (26.05±0.37 g/d), and from 8 to 12 wk of age (25.48±0.56 g/d) traits. The G/G genotype of the PGR gene showed superiority for LSB (7.51±0.13 kits) and litter size at weaning (6.53±0.14 kits) traits over the other genotypes. Regarding milk yield traits; the C/C, A/A and A/A genotypes of GH, IGF2 and PGR genes yielded more milk compared to the other genotypes. The means of total milk yield in 28 d for these genotypes were 2936±29 g, 2921±43 g and 2930±35 g, respectively. Thus, GH, IGF2 and PGR genes might be useful for marker-assisted selection programmes for improvement of rabbit growth, litter size and milk yield traits.

Maternal genetic effects (MGE) could affect meat quality traits such as intramuscular fat (IMF) and its fatty acid composition. However, it has been scarcely studied, especially in rabbits. The objectives of the present study were, first, to assess the importance of MGE on intramuscular fat and fatty acid composition by applying a Bayesian maternal animal model in two rabbit lines divergently selected for IMF. The second objective was to identify genomic regions and candidate genes of MGE that are associated with the traits of these offspring, using Bayesian methods in a Genome Wide Association Study (GWAS). Quantitative analyses were performed using data from 1982 rabbits, and 349 animals from the 9th generation and 76 dams of the 8th generation with 88,512 SNPs were used for the GWAS. The studied traits were IMF, saturated fatty acids (total SFA, C14:0; myristic acid, C16:0; palmitic acid and C18:0; stearic acid), monounsaturated fatty acids (total MUFA, C16:1n-7; palmitoleic acid and C18:1n-9; oleic acid), polyunsaturated fatty acids (total PUFA, C18:2n-6; linoleic acid, C18:3n-3; α-linolenic acid and C20:4n-6; arachidonic acid), MUFA/SFA and PUFA/SFA. The proportion of phenotypic variance explained by the maternal genetic effect ranged from 8 to 22% for IMF, depending on the model. For fatty acid composition, the proportion of phenotypic variance explained by maternal genetic effects varied from 10% (C18:0) to 46% (MUFA) in a model including both direct and additive maternal genetic effects, together with the common litter effect as a random variable. In particular, there were significant direct maternal genetic correlations for C16:0, C18:1n9, C18:2n6, SFA, MUFA, and PUFA with values ranging from −0.53 to −0.89. Relevant associated genomic regions were located on the rabbit chromosomes (OCU) OCU1, OCU5 and OCU19 containing some relevant candidates (TANC2, ACE, MAP3K3, TEX2, PRKCA, SH3GL2, CNTLN, RPGRIP1L and FTO) related to lipid metabolism, binding, and obesity. These regions explained about 1.2 to 13.9% of the total genomic variance of the traits studied. Our results showed an important maternal genetic effect on IMF and its fatty acid composition in rabbits and identified promising candidate genes associated with these traits.