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ABSTRACT: The current study aimed to compare luteal function, as measured by corpora lutea dynamics and progesterone secretion, in 10 sows with obesity/leptin resistance genotype (Iberian pig) and 10 females of lean commercial crosses (Large White × Landrace). In all the animals, the oestrous cycle was synchronized with progestagens, and ovulation was induced by exogenous gonadotrophins. Thereafter, number and size of follicles and plasma oestradiol concentration were determined at oestrus detection, and number and size of corpora lutea and progesterone concentration were evaluated from Day 4 to 12 of the cycle. There were no differences between genotypes in follicle population and oestradiol concentration, and ovulation rate (15.2±1.3 in Iberian vs 12.7±1.8 in LWxL sows); however, there was a higher percentage of Iberian than control sows showing luteal cysts (66.7% vs 30%, respectively; p<0.05). In both breeds, both total luteal area and plasma progesterone concentration grew linearly from Day 4 to 8 (p<0.01) and remained more stable between Days 8 and 12, without significant differences between genotypes. In conclusion, current study supports that ovulatory processes and luteal functionality are not the main limiting factors for prolificacy in a pig model of leptin resistance and obesity.
Reproduction in Domestic Animals 03/2011; 46(6):1011-6. · 1.36 Impact Factor
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ABSTRACT: This study compares follicular function and ovulatory efficiency in 20 sows with obesity/leptin resistance genotype (Iberian pig) and 20 females of lean commercial crosses (Large White × Landrace; LW×L). Estrous cycle was synchronized with progestagens; ovulation was induced with eCG and hCG, in half of the females of each group, to determine its effect. In females of both breeds not treated with gonadotropins, the number of follicles larger than 4.9 mm and the estradiol secretion increased throughout the follicular phase (P<0.05); estradiol values were similar at estrus detection (22.5±1.2 vs. 26.5±0.6 pg/ml respectively, for Iberian and LW×L sows). Moreover, ovulation rate was higher in Iberian pigs (15.3±1.3 CLs) than in LW×L (10.2±1.3 CLs; P<0.05), with mean progesterone values being 18.1±0.7 ng/ml in Iberian and 16.8±0.6 ng/ml in LW×L pigs. Thus, the preovulatory follicular growth and the ovulatory efficiency seem not to be the main limiting factors for reproductive efficiency in Iberian swine. The gonadotropins induced a significant increase, when compared to untreated females (P<0.05), in the number of follicles larger than 4.9 mm growing throughout the follicular phase; however, estradiol values at estrus were lower (P<0.05) in both breeds (9.2±0.7 pg/ml in Iberian vs. 8.6±0.8 pg/ml in LW×L), when compared with the nontreated animals, which suggests defective follicular function after gonadotropin stimulation. There were also no differences between genotypes in ovulation rate (15.2±1.3 vs. 12.7±1.8) and progesterone secretion (21.2±0.8 ng/ml in Iberian and 20.9±0.7 ng/ml in LW×L sows) in the treated animals. In conclusion, the current findings indicate that preovulatory follicular growth and ovulatory efficiency are not main limiting factors for prolificacy in a pig model of leptin resistance and obesity.
General and Comparative Endocrinology 10/2010; 170(1):200-6. · 3.27 Impact Factor
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ABSTRACT: Cytogenetic analysis of 58 boars at an artificial insemination (AI) centre revealed the presence of a reciprocal chromosome translocation, rcp(1;11)(q-;p+), in two Duroc boars. Pedigree analysis of these two boars suggested familial transmission of the chromosome rearrangement. The reproductive consequences of this translocation were determined in a herd of sows that had received semen doses from these and other boars. All sows underwent multiple AI, with different groups established retrospectively depending on the percentage of semen doses provided by the carrier boars ([number of carrier boar doses/total number doses provided] x 100): 0%, 25%, 50%, 75%, 100%. The fertility rates (percentage of successful multiple AIs/total multiple AIs) recorded for multiple AI including semen doses from the carrier boars were not significantly different from those recorded when all semen doses were supplied by normal-karyotype boars. A reduction in litter size of 29.38% was observed, however, in litters sired by one of the carrier boars when its participation in multiple AI was 100%. The number of live-born piglets per litter gradually decreased (P<0.05) as the percentage participation in multiple AI (25, 50, or 75%) of the carrier boar increased. In addition, both carrier boars sired some piglets with signs of cleft palate and complex malformations of the front legs; these died soon after birth. In conclusion, the boars carrying the translocation rcp(1;11)(q-;p+) showed reduced reproductive performance.
Theriogenology 02/2010; 74(1):67-74. · 1.96 Impact Factor
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ABSTRACT: The Iberian pig is an autochthonous breed of the Mediterranean area, reared extensively in the central and southern areas of Spain and Portugal and that is known worldwide for the production of Iberian ham. The characteristics of the Iberian ham are related to its abundance of intramuscular fat, owing to the high capacity of the pig to accumulate fat under its skin and between the muscular fibres. This ability to store excess fat enables survival during periods of scarcity and it has been found in other antique animal breeds and even in humans, being named as the thrifty genotype. The reproductive management of the Iberian pig, in spite of a lack of accurate information unlike in other swine breeds, is based on the assumption of lower reproductive precocity and efficiency than the modern commercial breeds. The current study characterized and compared the onset of puberty in gilts of Iberian breed and meat commercial crosses (Large White × Landrace) reared in the same conditions by assessing weekly plasma progesterone profiles. At the end of the experimental period, when the gilts became 180 days old, the percentage of Iberian females that had reached puberty was 72.2%, with a mean age and weight of 160.5 ± 2.6 days and 92.9 ± 4.7 kg, respectively. The percentage of Large White × Landrace cross-breed females reaching puberty at 180 days was only 15% (p < 0.05). The mean age and weight were 165.0 ± 4.1 days and 107.8 ± 2.2 kg (p < 0.05), respectively. Thus, converse to the traditional assumption, onset of puberty was advanced in Iberian gilts. These results are important for the reproductive management of the Iberian pig but, at the same time, may set the basis for future studies on the metabolism-reproduction link and, specifically, on the possible relationship between earlier accumulation of fat and attainment of puberty.
Reproduction in Domestic Animals 06/2009; 45(6):1003-7. · 1.36 Impact Factor
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ABSTRACT: Current study determined, in sows, the accuracy of ultrasonography for in vivo (n=8) and ex vivo (n=7) evaluation of corpora lutea (CLs) and follicles > or =1.5mm in size, by comparison with macroscopic findings in sliced ovaries. The accuracy for ex vivo detection of follicles increased with follicle size (P<0.05), being low for 1.5-1.9 mm follicles (65.9%) and higher for > or =6mm follicles (93.3%); differences between ultrasonographic and macroscopic observations were significant only for follicles smaller than 3.9 mm (P<0.05), due to underestimation. Ex vivo observation succeeded to detect presence or absence of CLs in all the ovaries; the efficiency for determining the exact number of CLs being 94.4%. The accuracy for in vivo detection of follicles also increased with follicle size (P<0.05), dropping to values lower than 40% for 1.5-1.9 mm follicles; therefore, there were significant differences between ultrasonographic and macroscopic observations (P<0.05). On the other hand, accuracy remained around 92% for > or =6mm follicles. Ultrasonography was useful again for detecting presence of CLs in all the ovaries; the efficiency for determining CLs number reached 86.7%, due to underestimation in ovaries with higher number of CLs (P<0.05). Overall, there were no significant differences when comparing the accuracy of ex vivo and in vivo scannings for determination neither of the number of follicles in each size-category larger than 1.9 mm nor of the presence of ovulations or of the CLs number in each ovary. In conclusion, the use of ultrasonography allows an accurate detection of the presence and number of CLs and follicles > or =2mm of diameter in sows, without significant differences between in vivo and ex vivo observations.
Theriogenology 04/2009; 71(9):1433-9. · 1.96 Impact Factor
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ABSTRACT: The aim of the present study was to evaluate the protective effect of L-glutamine (L-Gln) against cryopreservation injuries on boar sperm. In Experiment 1, L-Gln from 20 to 80 mM was evaluated as a supplement for a standard freezing extender (egg yolk - EY - 20%, and glycerol 3%). No significant improvement (P>0.05) was obtained for any post-thaw sperm parameter assessed (objective sperm motility - CASA system - and flow cytometric analysis of plasma and acrosomal membrane integrity -SYBR14/PI/PE-PNA- and plasma membrane stability -M540/YoPro1-). In Experiment 2, L-Gln was evaluated as a partial glycerol substitute in the freezing extender. Significant (P<0.05) enhancement of post-thaw sperm motion parameters was achieved in sperm frozen in the presence of 2% glycerol and 80 mM L-Gln compared to control (3% glycerol). In Experiment 3, L-Gln was evaluated as an EY substitute in the freezing extender, and no functional sperm were recovered after thawing sperm frozen in the presence of L-Gln and the absence of EY. In conclusion, L-Gln has the ability to cryoprotect boar sperm when it is used as a partial glycerol substitute in the freezing extender.
Animal reproduction science 12/2008; 115(1-4):149-57. · 1.56 Impact Factor
