Functional longevity in five rabbit lines founded on different criteria: Comparison at foundation and at fixed times after selection

[EN] The enhancement of rabbit female functional longevity, that is the ability to avoid voluntary culling, is a paramount aspect for the sustainability of meat rabbit production; this trait represents a direct indicator of female robustness. The objective of our study was to compare the functional longevity of five rabbit lines at their foundation and at fixed times during their selection processes. Four of them are maternal lines (A, V, H and LP) selected for litter size at weaning. The fifth line is the paternal line R, founded and selected for post-weaning daily gain from 28 to 63 days. The comparison at foundation involved the complete data set (from March 1980 to March 2013; records of 15,670 does) and pedigree (19,405 animals). Latter comparisons were made when all lines shared the same environmental and management conditions, from March 1997 to September 1998 and from March 2011 to September 2012. In these second comparisons, the same model as that used in the comparison at foundation was used, but now the additive effect was excluded, only data from the corresponding periods were considered. At their foundation, lines V, H and LP showed larger functional longevity than lines A and R, being LP line that with the longest productive life. In the latter comparisons, lines A and R still showing the lowest functional longevities. However, as the selection process evolves, the differences between these two lines and the others were reduced. It could be concluded that the average longevity of a population greatly depends on the criteria followed for its foundation. In addition, along the selection for litter size, the differences of longevity between lines tend to decrease, this is due to an unintended selection for functional longevity, since only offspring from females reaching three parturitions are selected as breeding animals for the next generation.Spanish National Research Plan, Grant/Award Number: AGL2011-30170 C02-01El Nagar, AG.; Baselga, M.; Mínguez, C.; Santacreu, M.; Sánchez, JP. (2021). Functional longevity in five rabbit lines founded on different criteria: Comparison at foundation and at fixed times after selection. Journal of Animal Breeding and Genetics. 138(4):508-517. https://doi.org/10.1111/jbg.12543S508517138

Association of GH gene polymorphism with growth and semen traits in rabbits

[EN] Although growth hormone (GH) gene mutations are described in several species, the studies concerning their variabilities and associations with economic traits in rabbits are scarce, particularly associations with semen traits. A total of 149 rabbit bucks from five populations (V-line=36, Moshtohor line=28, APRI line=42, cross ½A½M=23, and Gabali=20) were used in the present study to identify polymorphism of c.-78 C>T single nucleotide polymorphism (SNP) of GH gene among these populations and to investigate the association of GH gene polymorphism with body weight (BW), daily weight gain (DG) and semen traits. DNA was extracted from blood samples for genotyping of c.-78 C>T SNP of GH gene based on polymerase chain reaction with the restriction fragment length polymorphism (PCR-RFLP) technique. The genetic diversity of SNP C>T of GH gene was assessed in terms of genotypic and allelic frequencies, effective number of alleles (Ne), observed (Ho) and expected (He) heterozygosity, Hardy-Weinberg equilibrium (HWE), reduction in heterozygosity due to inbreeding (FIS) and polymorphism information content (PIC). Three genotypes of TT, CC and TC of PCR product of 231 bp of GH gene were detected and all the populations were in HWE in terms of GH gene. The highest Ne was obtained for the Moshtohor line (1.978), while the lowest allelic numbers were obtained for V-line (1.715) and Gabali breed (1.800). The highest genotype frequency of GH gene was 0.48 in TT genotype of V-line, 0.21 in CC genotype of Moshtohor line, 0.67 and 0.56 in TC genotype of ½A½M and Gabali rabbits (P<0.05). The highest frequency for C allele was recorded by Moshtohor line (0.45) and the lowest frequency by Gabali (0.32). The genetic diversity scores for GH gene were intermediate (Ho=0.551, He=0.471, PIC=0.358). The values of Ho ranged from 0.444 in V-line to 0.667 in ½A½M cross, while the values of He were 0.425 in V-line and 0.508 in Moshtohor line. The values of PIC were moderate and ranged from 0.332 in V-line to 0.375 in M-line. The highest FIS was observed in Moshtohor line (0.042) and the lowest value was observed in ½A½M cross (–0.413). The CT genotype of GH gene showed the highest and significant values for body weights at 4, 8, 10 and 12 wk (542, 1131, 1465 and 1861 g) and daily gains at intervals of 4-6 and 8-10 wk (23.1 and 26.5 g). Additionally, the CT genotype recorded the highest and significant values for volume of ejaculate (1.1 mL), sperm motility (57.6%), live sperm (85.6%), normal sperm (93.1%) and sperm concentration in semen (611×106/mL), along with the lowest and significant values for dead sperms (14.4%) and abnormal sperms (6.9%).The authors are very grateful to the Central Laboratory of the Faculty of Veterinary Medicine, Benha University, Egypt for the help and support in molecular genetic analyses. This work was financially supported by the research project entitled “Genetic improvement of local rabbit breeds by using molecular genetic techniques” from the Scientific Research Fund (SRF), Benha University, Egypt.Khalil, MHE.; Zaghloul, AR.; Iraqi, MM.; El Nagar, AG.; Ramadan, SI. (2021). Association of GH gene polymorphism with growth and semen traits in rabbits. 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Genetic analysis of functional longevity in a complete diallel crossing experiment involving four maternal rabbit lines

In a diallel cross between four maternal lines of rabbits, the four maternal lines and the corresponding crossbred females (does) were evaluated concerning functional longevity, estimating their crossbreeding components. Sixteen genetic groups were produced by using four maternal lines of rabbit (A, V, H and LP (L)). The groups were distributed over 4 Spanish farms. In all farms, the V line was present as the reference group. A total of 7,211 does’ longevity records were recorded. Using a Cox proportional hazard model of fixed effects, survival analysis was performed to study longevity analysing the hazard of death or culling. Does from lines A, H and V had similar risks of death or of being culled, and they were more susceptible compared with those from line L. The lowest hazard was associated with L line does. No significant differences were found between the average of all crosses and the V line except when comparing the V line to the cross between A and H lines, favouring the former (1.30 higher risk of replacement for AH animals). Significant differences between reciprocal crosses were observed between VH and HV, in favour of HV (0.72 of relative risk of replacement) and between LH and HL, in favour of HL (0.76 of relative risk). Line V had the highest risk due to the direct genetic effects, and these differences were significant with the lines H (1.40 of relative risk) and L (1.43 of relative risk). The differences in maternal genetic effects were small and not significant except between lines H and V in favour of V line (0.75 of relative risk). The estimated direct heterosis effects do not always follow the same trend but they showed the importance of the crossing between specialized lines to produce crossbred does for intensive meat rabbit production.info:eu-repo/semantics/acceptedVersio

Functional longevity in five rabbit lines founded on different criteria: Comparison at foundation and at fixed times after selection

The enhancement of rabbit female functional longevity, that is the ability to avoid voluntary culling, is a paramount aspect for the sustainability of meat rabbit production; this trait represents a direct indicator of female robustness. The objective of our study was to compare the functional longevity of five rabbit lines at their foundation and at fixed times during their selection processes. Four of them are maternal lines (A, V, H and LP) selected for litter size at weaning. The fifth line is the paternal line R, founded and selected for post-weaning daily gain from 28 to 63 days. The comparison at foundation involved the complete data set (from March 1980 to March 2013; records of 15,670 does) and pedigree (19,405 animals). Latter comparisons were made when all lines shared the same environmental and management conditions, from March 1997 to September 1998 and from March 2011 to September 2012. In these second comparisons, the same model as that used in the comparison at foundation was used, but now the additive effect was excluded, only data from the corresponding periods were considered. At their foundation, lines V, H and LP showed larger functional longevity than lines A and R, being LP line that with the longest productive life. In the latter comparisons, lines A and R still showing the lowest functional longevities. However, as the selection process evolves, the differences between these two lines and the others were reduced. It could be concluded that the average longevity of a population greatly depends on the criteria followed for its foundation. In addition, along the selection for litter size, the differences of longevity between lines tend to decrease, this is due to an unintended selection for functional longevity, since only offspring from females reaching three parturitions are selected as breeding animals for the next generation.info:eu-repo/semantics/acceptedVersio

Dietary Supplementation of <i>Silybum marianum</i> Seeds Improved Growth Performance and Upregulated Associated Gene Expression of Muscovy Ducklings (<i>Cairina moschata</i>)

The effect of feeding on diets supplemented with Silybum marianum L. dry seeds (SMS) on growth performance, mortality percentage, biochemical parameters, the expression profile of related genes, and genotoxic effect in Muscovy ducklings was evaluated during a brooding period of 4 weeks. Two hundred and forty one-day-old Muscovy ducks were randomly assigned to four treatment groups (60 ducklings/group), the first group fed on basal diet with no additives (control), and the second (4 g kg−1), third (8 g kg−1), and fourth (12 g kg−1) groups fed the basal diet supplemented with 0, 4, 8, and 12 g kg−1 diet SMS, respectively. A substantial improvement in live body weight (LBW), body weight gain (BWG), and growth rate (GR), and a decrease in feed conversion ratios (FCR) and mortality rate were shown in ducks fed a diet supplemented with either 8 g kg−1 or 12 g kg−1 SMS compared to the other groups. Relevant improvements in liver function, oxidative stress markers, purinergic cell energy, and brain appetite were recorded on ducklings fed diets supplemented with SMS. Moreover, diets which included 8 or 12 g kg−1 SMS positively upregulated the expression of growth hormone gene (GH) and antioxidant genes (SOD1, SOD2, and CAT). These results are consistent with the increase in liver activity SOD and CAT enzymes, resulting in less DNA fragmentation. Consequently, all the aforementioned improvements in biochemical parameters and gene expression profiling may explain the superiority of the treated ducklings compared with the control group. Conclusively, the SMS could be used as a natural feed additive to promote health status and improve the growth performance of small grower ducks during the brooding period

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care