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

Abstract

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.

Microbiome composition as a potential predictor of longevity in rabbits

“…Sichuan White and New Zealand rabbits, a higher abundance of Uncultured Eubacteriaceae was found in the Sichuan White rabbit group, which also exhibited a significantly higher survival rate (p < 0.05) compared to the New Zealand rabbit group [ 56 ]. Line A in this study was founded from New Zealand rabbits and had a lower survival rate than line LP [ 24 ], supporting the possible importance of the Uncultured Eubacteriaceae in modulating longevity. Blautia and Colidextribacter were found to be more abundant in line A and in group LLP.…”

“…Greater alpha diversity was observed in line LP compared to line A. It should be noted that line LP has greater longevity than line A [ 24 ]. Hence, these findings are consistent with the idea that high microbial diversity is beneficial for coping with environmental stress and promotes a good health status [ 49 , 50 ].…”

“…It is important to underline that the DLINES comparison involved two rabbit lines that are characterized by distinct genetic backgrounds. Line LP was founded based on longevity criteria [ 23 ], and it has consistently exhibited significantly greater longevity than line A [ 24 ]. The gut microbiota has been shown to be under genetic regulation [ 53 , 54 ] and this may explain the observed differences in hologenomes [ 55 ].…”

“…Line LP is a robust maternal line that was founded in 2002 by females with a minimum of 25 parities and with an average prolificacy per parity of nine or more, which is the average prolificacy of commercial rabbits in Spain [ 23 ]. Since its foundation, the LP line has consistently demonstrated longer longevity compared to line A, with a doe from line A being 1.8 times more likely to die or be culled than a doe from line LP, with a statistical probability of 99% [ 24 ]. The females for this experiment were reared in the same conditions and were allowed to reach the maximum number of parities.…”