Jean-Paul Laforest

Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada

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Publications (6)13.83 Total impact

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    ABSTRACT: The objective was to determine the effect of long-term dietary supplementation of two types of fish oil on lipid composition and steroidogenesis in adult pig testis. Twenty-four Duroc boars, aged 204.5 ± 9.4 d (body weight 128.1 ± 16.7 kg) received daily 2.5 kg of an iso-caloric basal diet supplemented with: 1) 62 g of hydrogenated animal fat (AF); 2) 60 g of menhaden oil (MO) containing 16% of eicosapentaenoic acid (EPA) and 18% of docosahexaenoic acid (DHA); or 3) 60 g of tuna oil (TO) containing 7% of EPA and 33% of DHA. After these diets were consumed for 7 mo, testicular hormones, phospholipid content, and fatty acid composition of individual phospholipids in testis were determined. Body and reproductive organ weights were not significantly affected by dietary treatments. Testicular tissue from boars fed a TO diet, followed by those receiving MO and AF diets, had the lowest level of phosphatidylethanolamine (TO < MO < AF; P < 0.01) but the highest sphingomyelin (TO > MO > AF; P < 0.01). For each phospholipid, boars fed either the MO or TO diet had increased total omega-3 fatty acids, particularly DHA (P < 0.01), by reciprocal replacement of total omega-6 fatty acids (20:4n-6, 22:5n-6). The MO diet increased EPA more than the other diets. Testicular concentrations of testosterone and estradiol were lower in boars fed a TO diet than a MO diet (P < 0.02). In conclusion, long-term dietary supplementation of fish oil, regardless of the EPA/DHA ratio, modified the fatty acid compositions in testis and affected steroid production of healthy adult boars, which may represent a promising models for future studies on fertility.
    Theriogenology 07/2011; 76(6):1134-45. DOI:10.1016/j.theriogenology.2011.05.022 · 1.85 Impact Factor
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    ABSTRACT: The effects of long-term dietary supplementation of fish oil (n-3 PUFA-rich) in adult male pigs on body condition as well as insulin sensitivity and secretion were examined. Fifteen Duroc boars aged 204.5 (sd 9.4) d (body weight 145.8 (sd 16.8) kg) received daily 2.5 kg basal diet with a supplement of: (1) 62 g hydrogenated animal fat (n 5); (2) 60 g menhaden oil containing 10.8 g DHA and 9.0 g EPA (n 6); (3) 60 g tuna oil containing 19.8 g DHA and 3.9 g EPA (n 4). Rations were balanced to be isoenergetic. After 7 months of treatments, oral glucose and meal tolerance tests were conducted after insertion of a catheter into the jugular vein. Dietary supplementation with n-3 PUFA altered the blood plasma profile: DHA and EPA increased whereas arachidonic acid decreased (P < 0.01). Plasma glucose, insulin and C-peptide responses to oral glucose and the test meal were not affected by treatments (P>0.34). For all animals, total body fat estimated from body weight and back fat thickness was correlated with both beta-cell function (by homeostasis model assessment (HOMA); r+0.63) and insulin sensitivity (index of whole-body insulin sensitivity and by HOMA; r - 0.63 and r+0.66, respectively). In conclusion, long-term supplementation with dietary n-3 PUFA did not affect insulin metabolism in healthy adult male pigs. The relationship between body fat and insulin sensitivity, well documented in human subjects, suggests that the adult male pig could be a promising animal model for studies on insulin metabolism.
    The British journal of nutrition 09/2009; 103(2):189-96. DOI:10.1017/S0007114509991590 · 3.34 Impact Factor
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    ABSTRACT: The objective was to determine the effects of folic acid+ glycine supplement on uterine metabolism of prostaglandin and mRNA expression of endometrial granulocyte-macrophage colony-stimulating factor (GM-CSF) in nulliparous (NYL) and multiparous Yorkshire-Landrace (YL) sows, and in multiparous Meishan-Landrace sows (ML). In each of these three groups, sows were randomly assigned to two treatments: 15 ppm folic acid + 0.6% glycine or no supplement. The dietary supplement was given from the estrus before mating to slaughter on Day 25 of pregnancy. At slaughter, endometrial tissue was collected to determine endometrial expression levels of GM-CSF mRNA, cyclooxygenase-1 (COX 1) and -2 (COX2) and to evaluate in vitro endometrial secretion of prostaglandin E-2 (PGE(2)) secretion. Allantoic fluid samples were also collected to determine the kconcentration of PGE(2), prostaglandin F-2alpha. (PGF(2alpha)), estradiol-17beta (E-2), progesterone( P-4), and transforming-growth factor-beta(2) (TGF-beta(2)). The allantoic contents of PGF(2alpha), E-2 and P-4,P- and endometrial in vitro secretion of PGE(2) were not significantly influenced by the folic acid + glycine supplement. The folic acid + glycine supplement tended (P < 0.07) to increase allantoic content of PGE(2) and TGF-beta(2) in all sows and increased (P < 0.05) endometrial expression of COX2, especially in NYL sows. The endometrial expression of COX1 was decreased (P < 0.05) by folic acid + glycine supplement, especially in multiparous YL sows. The allantoic contents of PGE2 and PGF(2alpha), were not significantly affected by sow type. However, NYL sows had higher (P < 0.05) endometrial in vitro secretion of PGE(2,) and allantoic content of P4 than multiparous YL and ML sows.
    Theriogenology 01/2004; 61(2-3):485-98. DOI:10.1016/S0093-691X(03)00213-9 · 1.85 Impact Factor
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    ABSTRACT: Folic acid and glycine are factors of great importance in early gestation. In sows, folic acid supplement can increase litter size through a decrease in embryonic mortality, while glycine, the most abundant amino acid in the sow oviduct, uterine, and allantoic fluids, is reported to act as an organic osmoregulator. In this study, we report the characterization of cytoplasmic serine hydroxymethyltransferase (cSHMT), T-protein, and vT-protein (variant T-protein) mRNA expression levels in endometrial and embryonic tissues in gestating sows on Day 25 of gestation according to the breed, parity, and folic acid + glycine supplementation. Expression levels of cSHMT, T-protein, and vT-protein mRNA in endometrial and embryonic tissues were performed using semiquantitative reverse transcription-polymerase chain reaction. We also report, for the first time, an alternative splicing event in the porcine T-protein gene. Results showed that a T-protein splice variant, vT-protein, is present in all the tested sow populations. Further characterizations revealed that this T-protein splice variant contains a coding intron that can adopt a secondary structure. Results demonstrated that cSHMT mRNA expression levels were significantly higher in sows receiving the folic acid + glycine supplementation, independently of the breed or parity and in both endometrial and embryonic tissues. Upon receiving the same treatment, the vT-protein and T-protein mRNA expression levels were significantly reduced in the endometrial tissue of Yorkshire-Landrace sows only. These results indicate that modulation of specific gene expression levels in endometrial and embryonic tissues of sows in early gestation could be one of the mechanism involved with the role of folic acid on improving swine reproduction traits.
    Biology of Reproduction 11/2002; 67(4):1259-67. DOI:10.1095/biolreprod.102.004432 · 3.45 Impact Factor
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    ABSTRACT: The present experiment aimed to determine the effects of supplements of folic acid (FA) alone or in combination with vitamin B12 on folate and homocysteine metabolism in gestating nulliparous Yorkshire-Landrace (YL) and multiparous Landrace (LD) occidental sows and multiparous Chinese Meishan-Landrace (ML) sows. LD sows were randomly assigned to two treatments: 0 or 15 mg FA/kg diet while YL and ML sows were assigned to three treatments: 0 mg FA/kg diet, 15 mg FA/kg or 15 mg vitamin B12/kg diet. Supplements were given from the oestrus preceding insemination up to slaughter on day 15 of gestation. At slaughter, a uterine flush was collected to determine uterine contents of homocysteine, methionine, tetrahydrofolate (THF), 5-methyl-THF, pyridoxal 5-phosphate (P5P) and vitamin B12. Blood samples were taken at first oestrus, at insemination and on days 5, 10 and 15 of gestation to determine plasma concentrations of homocysteine, methionine, THF, 5-methyl-THF, P5P, vitamin B12 and relative total folate-binding capacity. In occidental sows (YL and LD), the FA supplement tended to decrease uterine flush content of homocysteine (P=0.06) and concentrations of plasma homocysteine (P=0.09). Nulliparous YL sows had lower concentrations of plasma homocysteine, methionine, THF and 5-methyl-THF (P<0.05) than multiparous LD sows. Multiparous ML and LD sows had similar concentrations of plasma THF, 5-methyl-THF, methionine and vitamin B12, but ML sows had lower concentrations of plasma homocysteine (P<0.05). The vitamin B12 supplement increased concentrations of plasma vitamin B12 (P<0.05) both in multiparous ML and nulliparous YL sows, but had no effect on the composition of either uterine flush or plasma. The present results showed also that sows had a low vitamin B12 status (<200 pg/ml) and high circulating homocysteine levels (>15 microm) during the first 15 d of gestation. Furthermore, the vitamin B12 content in uterine secretions represented between 180 and 300 % of the total content in plasma. The low plasma concentrations of homocysteine in multiparous ML sows suggest a more efficient remethylation pathway which may not be dependent upon dietary supply of FA or vitamin B12. In nulliparous YL sows, low concentrations of both homocysteine and methionine suggest that the methionine requirement for protein deposition might have reduced the amount of methionine available for the methylation pathway. The results of the present experiment suggest that the reduction of uterine homocysteine may be an important aspect of the role of FA supplement on the uterine environment in occidental sows. The presence of high levels of vitamin B12 in uterine secretions merits further investigation in relation to embryonic development.
    British Journal Of Nutrition 10/2002; 88(3):253-63. DOI:10.1079/BJN2002653 · 3.34 Impact Factor
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Publication Stats

27 Citations
13.83 Total Impact Points

Institutions

  • 2011
    • Agriculture and Agri-Food Canada
      • Dairy and Swine Research and Development Centre (DSRDC)
      Ottawa, Ontario, Canada
  • 2004–2009
    • Laval University
      • Department of Animal Sciences
      Québec, Quebec, Canada