Feed restriction as a biostimulant of the production of oocyte, their quality and GDF-9 gene expression in rabbit oocytes.
The use of short-term feed restriction (R) without or with subsequent refeeding (F) as biostimulant of rabbit fertility was examined in this study. A total of 40 mature, non-pregnant, non-lactating New Zealand white female rabbits were allocated to five treatments. The rabbits were individually caged and fed a complete pelleted diet (16.7% CP; 13.1 CF; 2490kcalDE/kg). Rabbits on the control (C) treatment received 150g/d of the diet. Two groups of 8 rabbits received 70% of the control daily feed intake (105g/d; moderate restriction; M) and the other two groups received 50% of the control feed intake (75g/d; severe restriction; S) for 21d. At the end of this period, one group each of M and S fed rabbits were slaughtered for oocyte recovery. Rabbits in the remaining three groups (C, MF and SF) were retained for a further 8d before slaughter and fed the control level of the diet during this period. The effects on body weight, oocyte number and quality, GDF-9 gene expression in oocytes, and changes in serum levels of leptin and IGF-1 were recorded. Initial mean body weights were not significantly different ranging from 2.50±0.33kg (S) to 2.58±0.24kg (C). After 3wk on treatment the C rabbits were significantly heavier (2.65±0.32kg; P<0.05) than rabbits on the M (2.26±0.33kg) or S (2.10±0.33kg) treatments. Following 8d of refeeding, the remaining group of S treated rabbits (SF) were still significantly lighter (2.40±0.21kg; P<0.05) than C (2.71±0.31kg) with MF rabbits having an intermediate weight (2.50±0.20kg). The number of mature grade A oocytes recovered per ovary was significantly lower for control (3.3±0.35) than the refed treatments (MF 4.0±0.30; SF 4.5±0.39; P<0.05). Semi-quantitative PCR analysis of GDF-9 expression showed that control mature grade A oocytes had significantly lower levels of expression (1.27±0.20; P<0.05) than those of refed rabbits (MF 1.60±0.10; SF 1.39±0.01). Leptin and IGF-1 values for refed rabbits were significantly higher (P<0.05) than at the end of feed restriction and the start point. It was concluded that this biostimulant method has the potential to improve the fertility of rabbits.
Animal Reproduction & A. I, Department, National Research Center, Dokki, Tahrir Street, Egypt. dr.niveendaoud@gmail.com
Niveen M
NM
Daoud
Karima F
KF
Mahrous
Omaima H
OH
Ezzo
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D005260:Female; D005508:Food Deprivation; D018507:Gene Expression Regulation, Developmental; D055429:Growth Differentiation Factor 9 / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D020738:Leptin / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits / Q000502:physiology*
D000199:Actins; D055429:Growth Differentiation Factor 9; D020738:Leptin; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I