Rearing management of rabbit males selected by high growth rate: the effect of diet and season on semen characteristics

Abstract

-A total of sixty-six young males were used to evaluate the effect of low (L), medium (M) and high (H) concentrations of dietary digestible energy received during the rearing seasons (autumn and spring) on the performance and main semen characteristics of males for artificial insemination selected by a high growth rate. Males reared during the spring season presented a significantly higher weight at weaning than those reared during the autumn season (P < 0.001), and these differences were maintained until the end of the trial. The requirements of the males were easily covered as a general rule. In the autumn group, the males were unable to intake the digestible protein recommended only during their 3rd month of life, especially with low concentrate diets (P < 0.05). H males showed higher semen concentration and production during the autumn season, while L males showed a higher semen concentration and production than M males during the spring season, the H group showed intermediate values (P < 0.001). Males reared during the spring season showed significantly higher values of sperm concentration (P < 0.01) and production (P < 0.01). H males presented a lower percentage of spermatozoa with cytoplasmic droplets than the L group (P < 0.05) and the lowest values for sperm abnormalities during the autumn season, while the L group presented higher values for percentage abnormalities, especially during the last month controlled (P < 0.05). As a general rule, the main motility parameters controlled were not affected by the rearing diet received nor the season. These results seem to indicate that the management of rabbit males during the growing and rearing periods seem to significantly affect their subsequent performance and semen production.rabbit males / rearing / semen characteristics / dietary energy / season

Semen evaluation of two selected lines of rabbit bucks.

“…However, according to Castellini and Lattaioli (1999), VAP was 59.8-73.2 µm/sec and LIN 56.7-60.6% in rabbit semen at different sperm concentrations with 60.0 to 82.5% motility. Pascual et al (2004) also reported lower values for kinetic traits in the R line during the spring season, except for VSL and BCF, which were higher than those recorded in the current study. Theau-Clément et al (2007) reported that bucks selected for high body weight at 63 days of age produced semen with lower VAP and ALH than non selected bucks whereas, both lines produced semen with similar VSL and LIN.…”

“…This value is consistent with those found by Roca et al (2000 and in hybrid rabbits, Brun et al (2002) in purebred and crossbred rabbit bucks selected for litter size, and Lavara et al (2007a and b) in R line selected bucks. On the other hand, Pascual et al (2004) reported lower values in young (6-9 months) R line bucks during the spring season for the total sperm motility percentage (ranging from 30.6 to 47.0%) than those observed in the current research. This discrepancy may be ascribed to the different ages of the bucks.…”

“…In fact, no differences were observed for total ejaculate volume, sperm concentration and percentage of sperm abnormality between the lines. The overall means of these parameters were similar to the previous studies for ejaculate volume in the R line, for spermatozoa concentration (Pascual et al, 2004) in the R line during the spring season and for sperm abnormalities (García-Tomás et al, 2006) in two rabbit sire lines and their reciprocal crosses. However, Theau-Clément et al (2007) reported that the selection for high 63-d body weight of rabbit bucks reduced semen volume and increased sperm concentration without affecting the fertilizing capacity of the rabbit semen.…”

Rabbit reproductive performance after insemination with buserelin acetate extender

“…Despite the advances in understanding nutritional requirements (protein, fatty acid and energy, oligoelements such as Se or Zn, and vitamins, Castellini et al, 2000Castellini et al, , 2002Pascual et al, 2004), sperm evaluation (Brun et al, 2002;Lavara et al, 2005), semen extenders and conservation means such as jellification extenders (Roca et al, 2000;Lavara et al, 2000;Nagy et al, 2002;López-Gatius et al, 2005), optimal sperm dose (4 to 7.5 million per doe, Viudes de Castro and Vicente, 1997;Castellini and Lattioli, 1999) or new protocols to freeze rabbit sperm (Vicente and Viudes de Castro, 1996;Mocé et al, 2003;Si et al, 2006), progress in the application of AI remains subject to physiological and technical limitations.…”

Technical Note: Design of a large variable temperature chamber for heat stress studies in rabbits.

“…However, most of them were carried out by comparing the results obtained in different seasons [e.g. reproductive rabbit does (Marai et al, 2002), growing rabbits (Lebas and Ouhayoun, 1987;Frangiadaki et al, 2003), and rabbit males (Pascual et al, 2004)]. Other studies have been done using a climatic chamber where temperature (around 30°C) was maintained constant (Fernández-Carmona et al, 1995:2003Cervera et al, 1997;Amici et al, 1998;Zeferino et al, 2011), or for few minutes 42°C (Amici et al, 2000).…”