Ovulation rate and early embryonic survival rate in female rabbits of a synthetic line and a local Algerian population

Abstract

A higher litter size at birth has been reported in female rabbits from a Synthetic line than in those of the Local Algerian population. The aim of this work was to analyse whether this difference in litter size was due to a higher ovulation rate and/or embryonic survival rate in Synthetic line than in Local Algerian population. In total, 24 multiparous female rabbits from Synthetic line and 23 from Local population were used in this experiment. Litter size at birth was recorded up to the first 3 parities. Litter size was 20% higher in Synthetic line than Local population. At their 4 th gestation, the females were euthanized at 72 h post coitum. Synthetic line females had 50% more ova and embryos than those of Local population (+4.42 ova and +3.92 embryos, respectively). Synthetic line displayed a lower percentage of normal embryos and a larger number of unfertilized oocytes than Local population (-2.81% and +0.64 oocytes, respectively), but differences were not relevant. Synthetic line showed a lesser embryonic stage of development at 72 h post coitum, showing a higher percentage of early morulae (31.50 vs. 8.50%) and a lower percentage of compact morulae (51.45 vs. 78.65%) than Local population. No relevant difference was found for early embryonic survival rate between Synthetic line and Local population. In conclusion, the difference in litter size was mainly due to a higher ovulation rate in the Synthetic line, allowing more embryos to develop in this line.

Litter size components traits in two Algerian rabbit lines

“…The body weight of the females was similar between both groups and slightly lower than that reported by Belabbas et al (2016) and other maternal lines (Calle et al, 2017). The improvement in litter size of Synthetic line could be related to a modification in the litter size components traits.…”

“…The new commercial line has a higher growth rate (Belabbas et al, 2019) and a larger litter size than the local Algerian population (Sid et al, 2018). Also, Belabbas et al (2016) determined lower ovulation rate and number of embryos at 72 h post coitum in Local population than in Synthetic line. Strategies to improve the productivity of these populations adapted to heat stress are necessary to maintain the biodiversity of these genetic resources.…”

“…Litter size is limited by several components of traits such as ovulation rate, fertilisation and prenatal mortality (see review in Blasco et al, 1993a). Fertilisation rate is generally high, exceeding 90 to 95% (Peiró et al, 2014), and is therefore not considered a constraining component of litter size (Belabbas et al, 2016). However, ovulation rate is, together with pre and postimplantation mortality, the foremost component of litter size, and is also a limiting factor for its improvement (Laborda et al, 2011).…”

Rabbit meat in the east of Algeria: motivation and obstacles to consumption

“…Most of the research conducted on rabbits in Algeria to date has often focused on carcass production, fertility and yield (Zerrouki et al, 2014;Belabbas et al, 2016;Kadi et al, 2018;Belabbas, 2019). To the best of our knowledge, in Algeria, studies about rabbit meat production are scarcely reported.…”

Growth performances, carcass traits, meat quality, and blood metabolic parameters in rabbits of local Algerian population and synthetic line

“…[ 10 ] compared the synthetic line to the local Algerian population. This new synthetic line has shown a 20% more litter size than the local Algerian population, which is mainly due to their improve ovulation rate [ 11 ]. Several studies have been performed to assess the reproduction performance of the synthetic line [ 10 - 12 ].…”