Growth Traits In Rabbits Research Articles

Assessing the Genetic Response of Crossing on Post-Weaning Growth Traits in Rabbits

Assessing the Genetic Response of Crossing on Post-Weaning Growth Traits in Rabbits

Association of single nucleotide polymorphisms in Neuropeptide Y (NPY) and Phosphoglycerate Mutase 2 (PGAM2) genes with growth traits in rabbits

Genetic improvement of local rabbit breeds using modern approaches such as marker-assisted selection requires accurate and precise information about marker‒trait associations in animals with different genetic backgrounds. Therefore, this study was designed to estimate the association between two mutations located in the Neuropeptide Y (NPY, g.1778G > C) and Phosphoglycerate Mutase 2 (PGAM2, c.195 C > T) genes in New Zealand White (NZW), Baladi (BR), and V-line rabbits. The first mutation was genotyped using high-resolution melting, and the second mutation was genotyped using the PCR-RFLP method. The results revealed significant associations between the NPY mutation and body weight at 10 (V-line) and 12 weeks of age (NZW, BR, and V-line), body weight gain (BWG) from 10 to 12 weeks of age (BR), BWG from 6 to 12 weeks of age (NZW, BR, and V-line), average daily gain (NZW, BR, and V-line, and BR), growth rate (GR) from 8 to10 weeks (V-line), 10 to 12 weeks (BR), and GR from 6 to 12 weeks of age (BR, and V-line). The PGAM2 mutation was associated with body weight at 10 (V-line) and 12 (NZW, and V-line) weeks of age, with significant positive additive effects at 12 weeks of age in all breeds, and was associated with BWG from 8 to 10 and 10 to 12 in BR, and BWG from 6 to 12 weeks of age (NZW, and BR), and average daily gain (NZW, and BR), and was associated with GR form 8 to 10 weeks (BR), from10 to 12 weeks (BR, and V-line) and from 6 to 12 weeks (BR). The results highlighted the importance of the two mutations in growth development, and the possibility of considering them as candidate genes for late growth in rabbits.

Efficiency of leptin gene polymorphisms in the evaluation of the growth performance and carcass measurements of v-line and Baladi black rabbits

This study investigated the association between both polymorphisms and metabolic marker changes of the leptin gene, and body weight, weight gain, carcass traits, feed intake, and feed conversion ratio. Blood samples were collected from 60 V-line and 60 Baladi Black rabbits for DNA extraction and biochemical analysis. DNA sequencing of leptin (202-bp) revealed four non-synonymous single nucleotide polymorphism (SNPs) that characterized a number of V-line rabbits. Statistical analysis revealed that the identified SNPs were associated with rabbit growth and carcass measurements (p < 0.05). A discriminant analysis model showed a high classification percentage for the identified SNPs within and between breeds using body weight at 5-14 weeks of age (91.7%), slaughter traits (91.6%), feed intake, daily feed intake, and feed conversion ratio (76.7%). This study reveals that leptin gene could be a candidate for growth traits in rabbits enabling the development of marker-assisted selection (MAS) in different rabbit breeds.

Association between IRS-1, PPAR-γ and LEP genes polymorphisms and growth traits in rabbits

Single nucleotide polymorphisms are commonly associated with changes in quantitative traits, and have been considered useful markers for improving different traits in livestock. The current study aimed to explore the effect of three SNPs located in Insulin receptor substrate (IRS-1), Peroxisome proliferator-activated receptor γ (PPAR-γ), and Leptin (LEP) genes on the growth traits of rabbits. Individuals from three rabbit breeds were genotyped using RFLP-PCR. The IRS-1 variant (c.189T > G) was associated with post-weaning body weight, and body weight gains, However, the effect on growth rates was insignificant in Baladi Red and V-line rabbits. The PPAR-γ variant (c.207A > C) was significantly associated with 8-wk body weights in V-line rabbits, 10-wk body weights, and growth rates from 8 to 10 weeks of age in New Zealand rabbits. However, the differences between genotypes were insignificant for body weight gains and average daily gain. The LEP gene mutation (g.16079636C > G) had significant effects on body weights at 6 and 8 weeks of age in New Zealand White rabbits and 8 weeks of age in Baladi Red rabbits were associated with the presence of the C allele. Concludingly, the results stressed the importance of the IRS-1 gene in post-weaning growth and suggested the existence of breed-specific effects for PPAR-γ and LEP.

Effects of Genotype and Weaning Age Interaction on Growth Traits in Rabbits

Weaning age is an important factor that affects the growth and health of weaned animals. Therefore, the current experiment was conducted to study genotype (G) and weaning age (WA) interaction (G×WA) effects on growth traits of the animals belonged to two lines of rabbits (APRI and V line) reared under Egyptian conditions. Multiparous doe rabbits were serviced to obtain 225 litters with 1800 young rabbits at weaning. The weaning ages ranged from 26 to 43 days where the young rabbits were weaned at different ages (≥28 days, WA1; 28 < Treatment ≥ 35 days, WA2; 35 < Treatment ≥ 40 day, WA3 and 40< Treatment, WA4). Body weight (BW) from 4 to 16 weeks of age and corresponding average daily gain (ADGt1-t2) were measured. The BW significantly increased in APRI rabbits, compared to those in V line at the different ages where at the end of the fattening period, the difference was 105 g per animal with higher ADG. Regarding the weaning age effects, positive effects were observed where the highest BW was observed at the fattening period. The ADG of rabbits weaned in late weaning was higher than in early weaning with significant differences. The observed results suggest the existence of relevant G×WA interaction for the investigated traits. Therefore, the weaning age of 29-35 days is recommended for young APRI rabbits while it is suggested to wean the V rabbits after 35 days. The study confirmed that early weaning is not preferable for the rabbit under Egyptian conditions and it is better to wean young rabbits at the minimum age of 30 days to achieve the best BW and growth rate.

Genetic correlations for reproductive and growth traits in rabbits

The objective of this study was to obtain heritability estimates for reproductive (litter size at birth, number born alive, litter size at weaning) and growth traits (individual weaning weight, individual weight at the end of the fattening period), then determine the genetic correlation between them in a synthetic rabbit line. A total of 805 females, 3242 parities, and 18 472 growth records were measured from 2006 to 2017. A pentavariate animal model was used with reproductive and growth traits. Heritability ranged from 0.025 to 0.126 for reproductive traits and from 0.033 to 0.059 for growth traits. These traits showed a large coefficient of variation (from 32% to 56% for reproductive traits and from 21% to 28% for growth traits). The repeatability of reproductive traits was low and the common litter effect for growth traits was the most important component of total variance. The genetic and phenotypic correlations between reproductive and growth traits were high and negative, especially with weight at weaning (−0.848, −0.922, and −0.854 for litter size at birth, number born alive, and litter size at weaning, respectively). In conclusion, because of the high negative correlation between reproductive and growth traits, both reproductive and growth traits should be selected in independent lines and the response to selection should be due mainly to the high coefficient of variation of the traits.

Association of a synonymous mutation of the PGAM2 gene and growth traits in rabbits

Phosphoglycerate mutase (PGAM2) catalyzes the conversion of 3-phosphoglycerate into 2-phosphoglycerate and releases energy during glycolysis in muscle tissues. PGAM2 has been considered as a candidate gene to influence growth, development, and carcass traits in livestock. The aim of this study was to investigate the association between polymorphisms of PGAM2 and growth traits in rabbits. Three single nucleotide polymorphisms (SNPs) were identified by direct sequencing in 20 random individuals from three breeds, including c.-10C>T, c.195C>T, and c.414+17C>T. The c.195C>T was genotyped by PCR-RFLP in a total of 222 rabbits of three breeds (Tianfu black, 53 animals; Ira, 91 animals; Champagne, 78 animals). The average allele frequency among the breeds was 0.52 for allele T and 0.48 for C. The heterozygosity and effective number of alleles were 0.4992 and 1.996, respectively. The association results revealed the CT genotype of c.195C>T was associated significantly (P < 0.05) with greater body weight at 84 days of age (BW84) and with average daily weight gain (ADG). However, association of the genotypes with other production traits was not observed. The results of this study suggested PGAM2 is one of the candidate genes affecting BW84 and ADG in the rabbit.

Association between the IRS1 and FTO genes regulates body weight in rabbits.

Insulin receptor substrate (IRS) proteins play key roles in signal transduction in insulin and insulin-like growth factor signaling to control postnatal growth. The fat mass and obesity-associated (FTO) protein also play an essential role in postnatal growth. The aim of this study was to investigate the association between the IRS1 and FTO genes and the regulation of growth traits in rabbits. A total of nine synonymous SNPs were detected in the IRS1 coding sequence using direct sequencing, and the c.189G>T and c.2574G>A SNPs from two linkage disequilibrium blocks were further genotyped for association analysis in 216 New Zealand rabbits. The association results revealed that the TT genotype of c.189G>T and the AA genotype of c.2574G>A were significantly associated with higher body weight at 70 (BW70) and 84 (BW84) days of age and with higher average daily gain (P<0.05). Linear-regression analysis revealed that the two-gene combination model of FTO c.499G>A and IRS1 c.2574G>A was associated with BW70 and BW84. The combination model of the GA genotype of FTO c.499G>A with the AA genotype of IRS1 c.2574G>A was associated with preferred values for BW70 and BW84. The performance values for the FTO c.499G>A genotypes after stratification with regard to the IRS1 c.189G>T genotypes revealed that the TT genotype of IRS1 c.189G>T reduced the FTO c.499G>A significance associated with BW70 and BW84. Together, our data indicated that the IRS1 gene was associated with growth traits in rabbits. The IRS1 and FTO combination model may be exploited to assist breeders in selecting rabbits with preferred body weight.

Effect of protein source and enzyme supplementation on ileal protein digestibility and fattening performance in rabbits

An experiment was conducted to determine the effects of source of protein (soybean vs sunflower meal) and enzyme supplementation (no enzyme vs protease addition vs protease + xylanase addition) on digestion and growth traits of rabbits. Treatments were arranged factorially in six isonutritive diets. Two hundred and forty rabbits weaned at 25 or 35 days were used to measure dry matter and crude protein apparent ileal digestibility of diets at 35 or 45 days of age, respectively. Another one hundred and eighty animals weaned at 35 days were fed ad libitum in individual cages during four weeks to determine fattening performance. Source of protein did not affect digestion efficiency or feed conversion rate in the whole fattening period, but animals fed soybean meal-based diets showed higher feed intake, grew faster and had higher mortality than those fed sunflower meal-based diets. Addition of enzymes increased ileal apparent digestibility, especially in youngest animals when supplements contained xylanase besides protease activity. Enzyme supplementation did not affect any of the growth traits studied, but decreased fattening mortality in sunflower meal-based diets.

Effect of genotype on growth traits of rabbits

Genotype effect on growth traits of rabbits were investigated in a randomised complete block design using one hundred and twenty - 10-week-old breeding rabbits. The breeds of rabbits used were New Zealand white, Dutch, chinchilla and were characterized using body weight (BW), heart girth (HG), shoulder to tail (ST), head to shoulder (HS), ear length (EL) tail length (TL), and height at withers (HW). The result reveals that daily feed intake, average daily weight gain and feed efficiency ratio were significantly (P 0.01) among the different genotype x sex sub-class for all the parameters measured. Evidence from the study indicates that association between body weight and linear body traits in the three genotype of rabbits were linear. The results show that the reliability of R2 increased with increasing number of measurements combined. The result on the Dutch breed shows that the trait combination involving ear length heart girth and heart at withers contributed 971% to body weight, while combination of ear length and heart girth contributed 96.9 to body weight. The results indicate that for chinchilla two combinations would best predict body weight at 20 weeks of age. Heart girth contributed 93.5% to the total variability in body weight. Combination of heart girth and height at withers contributed 94.0% variability in body weight. The study provide good guide to select characters of good values for crossing in order to achieve good carcass quality. Keywords : genotype, growth traits, rabbit International Journal of Agriculture and Rural Development Vol. 5 2004: 61-68

Effect of embryo cryopreservation techniques on reproductive and growth traits in rabbits

Effets des techniques de cryoconservation d'embryons sur les caracteres de croissance et de reproduction du lapin. Les effets des techniques de collecte, de cryoconservation et de transfert d'embryons sur les caracteres de croissance et de reproduction du lapin on ete etudies. Compares a des animaux concus et nes de facon naturelle, les animaux issus d'embryons cryoconserves sont penalises sur le gain moyen quotidien de 1,72 g.j -1 (p < 0,05) pendant l'engraissement. Cette difference disparait lorsqu'elle est analysee sur les descendants des animaux issus d'embryons cryoconserves. Les effets de la classe des tailles de portee etaient lineaires pour les poids au sevrage et a l'abattage; ils etaient non lineaires pour le gain moyen quotidien, mettant en evidence l'independance de ce caractere par rapport aux effets maternels. Il n'y avait pas de differences entre les animaux pour la taille de la portee ou l'intervalle entre les mises bas. Les caracteres de croissance etaient affectes par les effets de la saison (706,8 versus 654,3 g pour le poids au sevrage et 1940,6 versus 1875,1 g pour le poids a l'abattage; printemps versus ete, p < 0,05). La taille de la portee etait la plus faible en ete et l'intervalle entre mises bas etait le plus eleve en ete (52,3 versus 45,4 j; ete versus printemps, p < 0,05). Il est conclu que les experiences utilisant des animaux issus d'embryons cryoconserves doivent etre realisees sur les descendants de ces animaux et non sur ces animaux eux-memes, tout specialement pour les caracteres de croissance, afin d'eviter les eventuels effets negatifs observes dans cette etude.