Evaluation of maize grain and polyunsaturated fatty acid (PUFA) as energy sources for breeding rams based on hormonal, sperm functional parameters and fertility
Sellappan Selvaraju A D , Priyadarshini Raju A C , Somu Bala Nageswara Rao B , Subbarao Raghavendra A , Sumantha Nandi A , Dhanasekaran Dineshkumar B , Allen Thayakumar A , Shivashanmugam Parthipan A and Janivara Parameswaraiah Ravindra A
+ Author Affiliations
- Author Affiliations
A Animal Physiology Division, National Institute of Animal Nutrition and Physiology, Adugodi, Bangalore, India.
B Animal Nutrition Division, National Institute of Animal Nutrition and Physiology, Adugodi, Bangalore, India.
C Present address: Physiology, Reproduction and Shelter Management Division, Central Institute for Research on Goats, Makhdoom, UttarPradesh, India.
D Corresponding author. Email: selvarajuars@rediffmail.com
Reproduction, Fertility and Development 24(5) 669-678 https://doi.org/10.1071/RD11229
Submitted: 7 September 2011 Accepted: 17 October 2011 Published: 28 November 2011
Abstract
The objective of the present study was to elucidate the effect of different sources of dietary energy (maize vs polyunsaturated fatty acid (PUFA) on semen functional parameters and fertility of adult rams. Eighteen adult rams were divided into two groups (maize and PUFA, n = 9). The main energy source for the rams in the maize group was coarsely ground maize grain, whereas in the PUFA group it was sunflower oil (rich in 18 : 2 linoleic acid, an omega-6 acid). The ration was fed for a minimum period of 60 days and thereafter semen was collected for evaluation. The proportion of progressive forward motility was significantly (P < 0.05) higher in the PUFA group compared with the maize group. Sperm lipid peroxidation as measured by malondialdehyde formation (µM per 1 × 109 spermatozoa) was significantly (P < 0.05) higher in the PUFA group compared with the maize group. When the semen was diluted with Tris–egg yolk–citrate buffer and incubated for 24 h at 4°C, the proportions of plasmalemma integrity, the sperm subpopulation positive for functional membrane and acrosomal integrities, and mitochondrial membrane potential were significantly (P < 0.05) higher in PUFA-fed than in maize-fed animals. The different sources of energy did not influence the serum and seminal plasma IGF-I levels. The cleavage rate (percentage) did not differ significantly between PUFA- (45.4 ± 4.91) and maize- (44.63 ± 6.8) fed animals. In conclusion, PUFA feeding influenced sperm quality by altering or stabilising membrane integrity. The present study indicates that PUFA may improve semen quality but did not improve in vitro fertilisation.
Additional keywords: cleavage rate, IGF-I, lipid peroxidation, membrane integrity, mitochondrial membrane potential, motility.
References
Adeel, M., Ijaz, A., Aleem, M., Rehman, H., Yousaf, M. S., and Jabbar, M. A. (2009). Improvement of liquid and frozen–thawed semen quality of Nili-Ravi buffalo bulls (Bubalus bubalis) through supplementation of fat. Theriogenology 71, 1220–1225.| Improvement of liquid and frozen–thawed semen quality of Nili-Ravi buffalo bulls (Bubalus bubalis) through supplementation of fat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXktF2nurs%3D&md5=ce425088851952f998d5c80c49d6095eCAS | 19246083PubMed |
Beam, S. W., and Butler, W. R. (1997). Energy balance and ovarian follicle development prior to the first ovulation postpartum in dairy cows receiving three levels of dietary fat. Biol. Reprod. 56, 133–142.
| Energy balance and ovarian follicle development prior to the first ovulation postpartum in dairy cows receiving three levels of dietary fat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXis1Kguw%3D%3D&md5=86df3ceb7a9a2bf9a1e18b196133a397CAS | 9002642PubMed |
Blache, D., Chagas, L. M., Blackberry, M.., Vercoe, P. E., and Martin, G. B. (2000). Metabolic factors affecting the reproductive axis in male sheep. J. Reprod. Fertil. 120, 1–11.
| 1:CAS:528:DC%2BD3cXntlCitbg%3D&md5=659ff0b8e23ad3b7e5d92e8e64e5b0fcCAS | 11006140PubMed |
Breier, B. H., Gallaher, B. W., and Gluckman, P. D. (1991). Radioimmunoassay for insulin-like growth factor-I: solutions to some potential problems and pitfalls. J. Endocrinol. 128, 347–357.
| Radioimmunoassay for insulin-like growth factor-I: solutions to some potential problems and pitfalls.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3MXhtFGiur8%3D&md5=3d2078f48615e930aa00417e7b308047CAS | 1707433PubMed |
Brock, B. J., and Waterman, M. R. (1999). Biochemical differences between rat and human cytochrome P450c17 support the different steroidogenic needs of these two species. Biochemistry 38, 1598–1606.
| Biochemical differences between rat and human cytochrome P450c17 support the different steroidogenic needs of these two species.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXis1Grtw%3D%3D&md5=35b89f35d0aa5a50e19fe888949c861aCAS | 9931027PubMed |
Burke, J. M., Carroll, D. J., Rowe, K. E., Thatcher, W. W., and Stormshak, F. (1996). Intravascular infusion of lipid into ewes stimulates production of progesterone and prostaglandin. Biol. Reprod. 55, 169–175.
| Intravascular infusion of lipid into ewes stimulates production of progesterone and prostaglandin.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XltlKnsbY%3D&md5=8c8a05e7534b1a7c6fa1aeaf81e87e08CAS | 8793072PubMed |
Butler, J. H., and Gluckman, P. D. (1986). Circulating insulin-like growth factor-binding proteins in fetal, neonatal and adult sheep. J. Endocrinol. 109, 333–338.
| Circulating insulin-like growth factor-binding proteins in fetal, neonatal and adult sheep.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL28XktVWgsb4%3D&md5=94770645361b0f8691d1468018bacc09CAS | 3734667PubMed |
Byers, F. M., and Schelling, G. T. (1988). Lipids in ruminant nutrition. In ‘The Ruminant Animal: Digestive Physiology and Nutrition’ (Ed. D. C. Church.) pp. 298–310. (Prentice-Hall: Inglewood Cliffs, NJ, USA.)
Coppock, C. E., and Wilks, D. L. (1991). Supplemental fat in high-energy rations for lactating cows: effects on intake, digestion, milk yield and composition. J. Anim. Sci. 69, 3826–3837.
| 1:STN:280:DyaK38%2FktFakuw%3D%3D&md5=081d3d1003fd239859386471b05fe2fdCAS | 1938662PubMed |
Cribier, S., Morrot, G., and Zachowski, A. (1993). Dynamics of the membrane lipid phase. Prostaglandins Leukot. Essent. Fatty Acids 48, 27–32.
| Dynamics of the membrane lipid phase.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3sXnsFClsg%3D%3D&md5=76a8ad4c8e8ba4b4096a3dad20de6a3fCAS | 8424120PubMed |
Francis, G. L., Owens, P. C., McNeil, K. A., Wallace, J. C., and Ballard, F. J. (1989). Purification, amino-acid sequences and assay cross-reactivities of porcine insulin-like growth factor-I and -II. J. Endocrinol. 122, 681–687.
| Purification, amino-acid sequences and assay cross-reactivities of porcine insulin-like growth factor-I and -II.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXlt1Oiu7Y%3D&md5=bce0ed376b5b8ca0a12cb9c8d42d7584CAS | 2809477PubMed |
Garcia, M. R., Amstalden, M., Morrison, C. D., Keisler, D. H., and Williams, D. H. (2003). Age at puberty, total fat and conjugated linoleic acid content of carcass, and circulating metabolic hormones in beef heifers fed a diet high in linoleic acid beginning at four months of age. J. Anim. Sci. 81, 261–268.
| 1:CAS:528:DC%2BD3sXhtFagtro%3D&md5=c3a4d1ef7c281f29e1e101ee17c03182CAS | 12597397PubMed |
Grum, D. E., Drackley, J. K., Hansen, L. R., and Cremin, J. D. (1996). Production, digestion and hepatic lipid metabolism of dairy cows fed increased energy from fat or concentrate. J. Dairy Sci. 79, 1836–1849.
| Production, digestion and hepatic lipid metabolism of dairy cows fed increased energy from fat or concentrate.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XmslGntr8%3D&md5=c385200dd4c648cb0085661154039627CAS | 8923255PubMed |
Gurr, M. I., Harwood, J. L., and Frayn, K. N. (2002). ‘Lipid Biochemistry: An Introduction’. 5th edn. (Blackwell Science Ltd.: Oxford.)
Hafez, B., and Hafez, E. S. E. (2000). ‘Reproduction in Farm Animals’. (Lippincot Williams & Wilkins: Baltimore, MD.)
Hughes, J., Kwong, W. Y., Li, D., Salter, A. M., Lea, R. G., and Sinclair, K. D. (2011). Effects of omega-3 and -6 polyunsaturated fatty acids on ovine follicular cell steroidogenesis, embryo development and molecular markers of fatty acid metabolism. Reproduction 141, 105–118.
| Effects of omega-3 and -6 polyunsaturated fatty acids on ovine follicular cell steroidogenesis, embryo development and molecular markers of fatty acid metabolism.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXisVehs7k%3D&md5=0b79c84779077795a1a17b116a361b17CAS | 21045166PubMed |
Indian Council of Agricultural Research (1985). ‘Nutrient Requirements of Livestock and Poultry’. pp. 5–7. (ICAR: New Delhi.)
James, P. S., Wolfe, C. A., Mackie, A., Ladha, S., Prentice, A., and Jones, R. (1999). Lipid dynamics in the plasma membrane of fresh and cryopreserved human spermatozoa. J. Hum. Reprod. 14, 1827–1832.
| Lipid dynamics in the plasma membrane of fresh and cryopreserved human spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK1MzjtVKrsw%3D%3D&md5=1a0a8594b3b57dbbdd71eb93e054a35aCAS |
Jenkins, T. C. (1993). Lipid metabolism in the rumen. J. Dairy Sci. 76, 3851–3863.
| Lipid metabolism in the rumen.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXhtlShtb4%3D&md5=79a8f415936aa335e81628fc43ea40d4CAS | 8132891PubMed |
Kelso, K. A., Redpath, A., Noble, N. H. C., and Speake, B. K. (1997). Lipid and antioxidant changes in spermatozoa and seminal plasma throughout the reproductive period of bulls. J. Reprod. Fertil. 109, 1–6.
| Lipid and antioxidant changes in spermatozoa and seminal plasma throughout the reproductive period of bulls.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXhs1Gnt70%3D&md5=3b349bb4807f833d4fabbba2e59eba68CAS | 9068407PubMed |
Kumaresan, A., Ansari, M. R., and Garg, A. (2006). Modulation of post-thaw sperm functions with oviductal proteins in buffaloes. Anim. Reprod. Sci. 90, 73–84.
| Modulation of post-thaw sperm functions with oviductal proteins in buffaloes.Crossref | GoogleScholarGoogle Scholar |
Lammoglia, M. A., Willard, S. T., Hallford, D. M., and Randel, R. D. (1997). Effects of dietary fat on follicular development and circulating concentrations of lipids, insulin, progesterone, estradiol-17 beta, 13,14-dihydro-15-ketoprostaglandin F(2 alpha) and growth hormone in estrous cyclic Brahman cows. J. Anim. Sci. 75, 1591–1600.
| 1:CAS:528:DyaK2sXjs1GlurY%3D&md5=1cace0ace3fdefe35b55910bf4ee59ffCAS | 9250522PubMed |
Lenzi, A., Picardo, M., Gandini, L., and Dondero, F. (1996). Lipids of the sperm plasma membrane: from polyunsaturated fatty acids considered as markers of sperm function to possible scavenger therapy. Hum. Reprod. Update 2, 246–256.
| Lipids of the sperm plasma membrane: from polyunsaturated fatty acids considered as markers of sperm function to possible scavenger therapy.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXotVGgtLw%3D&md5=20c377a1c913379f5f7de242e8e139a2CAS | 9079417PubMed |
Leroy, J. L. M. R., Van Hoeck, V., Clemente, M., Rizos, D., Gutierrez-Adan, A., Van Soom, A., Uytterhoeven, M., and Bols, P. E. J. (2010). The effect of nutritionally induced hyperlipidaemia on in vitro bovine embryo quality. Hum. Reprod. 25, 768–778.
| The effect of nutritionally induced hyperlipidaemia on in vitro bovine embryo quality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXitFeitr8%3D&md5=b0f7e6536db7b75d0e41d7a38ffd1f76CAS |
Lu, J. C., Chen, F., Xu, H. R., Huang, Y. F., and Lu, N. O. (2007). Standardization and quality control for determination of fructose in seminal plasma. J. Androl. 28, 207–213.
| Standardization and quality control for determination of fructose in seminal plasma.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXjslertb8%3D&md5=a75e17402d6e5ce3feefe45e63bfa689CAS | 17135632PubMed |
Macpherson, M. L., Simmen, R. C. M., Simmen, F. A., Hernandez, J., Sheerin, B. R., Varner, D. D., Loomis, P., Cadario, M. E., Miller, C. D., Brinsko, S. P., Rigby, S., and Blanchard, T. L. (2002). Insulin-like growth factor-I and insulin-like growth factor binding protein-2 and -5 in equine seminal plasma: association with sperm characteristics and fertility. Biol. Reprod. 67, 648–654.
| Insulin-like growth factor-I and insulin-like growth factor binding protein-2 and -5 in equine seminal plasma: association with sperm characteristics and fertility.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XlsFKqur4%3D&md5=2703f4788297c8ea4d3726ea88b7a865CAS | 12135910PubMed |
Maldjian, A., Pizzi, F., Gliozzi, T., Cerolini, S., Penny, P., and Noble, R. (2005). Changes in sperm quality and lipid composition during cryopreservation of boar semen. Theriogenology 63, 411–421.
| Changes in sperm quality and lipid composition during cryopreservation of boar semen.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXjsVSm&md5=eea4825fbec546b79e7f57542ba6a341CAS | 15626408PubMed |
Mattos, R., Staples, C. R., and Thatcher, W. W. (2000). Effects of dietary fatty acids on reproduction in ruminants. J. Reprod. Fertil. 5, 38–45.
| 1:CAS:528:DC%2BD3cXotVyisQ%3D%3D&md5=c3a200a7cc44711967c9689e8f7fe265CAS |
McGuire, M. A., Vincini, J. L., Bauman, D. E., and Veenhuizen, J. J. (1992). Insulin-like growth factors and binding proteins in ruminants and their nutritional regulation. J. Anim. Sci. 70, 2901–2910.
| 1:CAS:528:DyaK38XlvFSksbY%3D&md5=6e9a980c350a9af0d1df424c4dff4325CAS | 1383181PubMed |
Mitre, R., Cheminade, C., Allaume, P., Legrand, P., and Legrand, A. B. (2004). Oral intake of shark-liver oil modifies lipid composition and improves motility and velocity of boar sperm. Theriogenology 62, 1557–1566.
| Oral intake of shark-liver oil modifies lipid composition and improves motility and velocity of boar sperm.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXnvV2rtro%3D&md5=6fff31bfb36a663bc48b06e36396ec5eCAS | 15451263PubMed |
Moallem, U., Folman, Y., Bor, A., Arav, A., and Sklan, D. (1999). Effect of calcium soaps of fatty acids and administration of somatotropin on milk production, preovulatory follicular development, and plasma and follicular fluid lipid composition in high-yielding dairy cows. J. Dairy Sci. 82, 2358–2368.
| Effect of calcium soaps of fatty acids and administration of somatotropin on milk production, preovulatory follicular development, and plasma and follicular fluid lipid composition in high-yielding dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXnsVGnur4%3D&md5=8d5f3f92c8de43df24048e4b6e2ef613CAS | 10575602PubMed |
National Research Council (2007). ‘Nutrient Requirements of Small Ruminants: Sheep, Goat, Cervids and New-World Camelids’. (National Research Council, Committee on Nutrient Requirement of Small Ruminants: Washington DC.)
Oldick, B. S., Staples, C. R., Thatcher, W. W., and Gyawu, P. (1997). Abomasal infusion of glucose and fat – effect on digestion, production and ovarian and uterine function of cows. J. Dairy Sci. 80, 1315–1328.
| Abomasal infusion of glucose and fat – effect on digestion, production and ovarian and uterine function of cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXks1Ogsrw%3D&md5=a6e26d733e2c89c5d8360bc5fb05764fCAS | 9241593PubMed |
Perrier, R., Michalet-Doreau, B., Bauchart, D., and Doreau, M. (1992). Assessment of an in situ technique to estimate the degradation of lipids in the rumen. J. Sci. Food Agric. 59, 449–455.
| Assessment of an in situ technique to estimate the degradation of lipids in the rumen.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XmsFSntL4%3D&md5=e706e55c0d2b242f9b91c2830891161aCAS |
Poulos, A., Sharp, P., Johnson, D., White, I., and Fellenberg, A. (1986). The occurrence of polyenoic fatty acids with greater than 22 carbon atoms in mammalian spermatozoa. Biochem. J. 240, 891–895.
| 1:CAS:528:DyaL2sXjt1Wq&md5=07688cd9f08b7a4624981295b0c8b34aCAS | 3827878PubMed |
Robertson, J. A., Thomas, J. K., and Burdick, D. (1971). Chemical composition of the seed of sunflower hybrids and open-pollinated varieties. J. Food Sci. 36, 873–876.
| Chemical composition of the seed of sunflower hybrids and open-pollinated varieties.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE3MXlsFSmtLg%3D&md5=b42d29a96fcb57e44fb5e95b2c207613CAS |
Robinson, R. S., Pushpakumara, P. G. A., Cheng, Z., Peters, A. R., Abayasekara, D. R. E., and Wathes, D. C. (2002). Effects of dietary polyunsaturated fatty acids on ovarian and uterine function in lactating dairy cows. Reproduction 124, 119–131.
| Effects of dietary polyunsaturated fatty acids on ovarian and uterine function in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XmtFaksLo%3D&md5=fdf4c1c542001e7a540534f37711adb1CAS | 12090925PubMed |
Ryan, D. P., Spoon, R. A., and Williams, G. L. (1992). Ovarian follicular characteristics, embryo recovery and embryo viability in heifers fed high-fat diets and treated with follicle-stimulating hormone. J. Anim. Sci. 70, 3505–3513.
| 1:CAS:528:DyaK3sXnvF2mtw%3D%3D&md5=10bc6e93358dca884b33f242893adc30CAS | 1459913PubMed |
Santos, J. E. P., Bilby, T. R., Thatcher, W. W., Staples, C. R., and Silvestre, F. T. (2008). Long-chain fatty acids of diet as factors influencing reproduction in cattle. Reprod. Domest. Anim. 43, 23–30.
| Long-chain fatty acids of diet as factors influencing reproduction in cattle.Crossref | GoogleScholarGoogle Scholar |
Sauerweina, H., Breier, B. H., Gallaher, B. W., Götz, C., Küfner, G., Montag, T., Vickers, M., and Schallenberger, E. (2000). Growth-hormone treatment of breeding bulls used for artificial insemination improves fertilization rates. Domest. Anim. Endocrinol. 18, 145–158.
| Growth-hormone treatment of breeding bulls used for artificial insemination improves fertilization rates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXhtFamu7c%3D&md5=caebee74cf5ab550e2565298b8add5d7CAS |
Scislowski, V., Bauchart, D., Gruffat, D., Laplaud, P. M., and Durand, D. (2005). Effects of dietary n-6 or n-3 polyunsaturated fatty acids protected or not against ruminal hydrogenation on plasma lipids and their susceptibility to peroxidation in fattening steers. J. Anim. Sci. 83, 2162–2174.
| 1:CAS:528:DC%2BD2MXpsFGitL0%3D&md5=4704b23f10baa57e0d4a1a182ec51588CAS | 16100072PubMed |
Selvaraju, S., Ravindra, J. P., Ghosh, J., Gupta, P. S. P., and Suresh, K. P. (2008). Evaluation of sperm functional attributes in relation to in vitro sperm–zona pellucida binding ability and cleavage rate in assessing frozen–thawed buffalo (Bubalus bubalis) semen quality. Anim. Reprod. Sci. 106, 311–321.
| Evaluation of sperm functional attributes in relation to in vitro sperm–zona pellucida binding ability and cleavage rate in assessing frozen–thawed buffalo (Bubalus bubalis) semen quality.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1c3ptVSlsQ%3D%3D&md5=d09384661011e586201676c4fb5dc39aCAS | 17576042PubMed |
Sinclair, H. M. (1984). Essential fatty acids in perspective. Hum. Nutr. Clin. Nutr. 38, 245–260.
| 1:STN:280:DyaL2c3ovVOqtQ%3D%3D&md5=576eda1aadcba81f2b4daca91b3e199fCAS | 6469703PubMed |
Staples, C. R., Burke, J. M., and Thacther, W. W. (1998). Influence of supplemental fats on reproductive tissues and performance of lactating cows. J. Dairy Sci. 81, 856–871.
| Influence of supplemental fats on reproductive tissues and performance of lactating cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXitlyht7c%3D&md5=b59853bfc9025fa29702b793e79e88bbCAS | 9565891PubMed |
Strzezek, J., Fraser, L., Kuklinska, M., Dziekonska, A., and Lecewicz, M. (2004). Effect of dietary supplementation with polyunsaturated fatty acids and antioxidants on biochemical characteristics of boar semen. J. Reprod. Biol. 4, 271–287.
Surai, P. F., Blesbois, E., Grasseau, I., Chalah, T., Brillard, J. P., Wishart, G. J., Cerolini, S., and Sparks, N. H. (1998). Fatty acid composition, glutathione peroxidase and superoxide dismutase activity and total antioxidant activity of avian semen. Comp. Biochem. Physiol., Part B. Biochem. Mol. Biol. 120, 527–533.
| Fatty acid composition, glutathione peroxidase and superoxide dismutase activity and total antioxidant activity of avian semen. Comp. Biochem. Physiol., Part B.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK1M%2FgsVSrsg%3D%3D&md5=33d9072363dc480a3e6619130d8cbb2fCAS |
Talavera, F., Park, C. S., and Williams, G. L. (1985). Relationships among dietary lipid intake, serum cholesterol and ovarian function in Holstein heifers. J. Anim. Sci. 60, 1045–1051.
| 1:CAS:528:DyaL2MXitF2qt70%3D&md5=af6316f07e1d94f9445f41882e9cbecbCAS | 4039314PubMed |
Thomas, M. G., and Williams, G. L. (1996). Metabolic hormone secretion and FSH-induced superovulatory responses of beef heifers fed dietary fat supplements containing predominantly saturated or polyunsaturated fatty acids. Theriogenology 45, 451–458.
| Metabolic hormone secretion and FSH-induced superovulatory responses of beef heifers fed dietary fat supplements containing predominantly saturated or polyunsaturated fatty acids.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28Xit1Ght7c%3D&md5=de30a3c092bf94cbed6ff607d7524a26CAS | 16727808PubMed |
Thomas, M. G., Bao, B., and Williams, G. L. (1997). Dietary fats varying in their fatty acid composition differentially influence follicular growth in cows fed isoenergetic diets. J. Anim. Sci. 75, 2512–2519.
| 1:CAS:528:DyaK2sXlvFKnu7Y%3D&md5=3a2e5fab8b4c777d879a50b7d41b05c2CAS | 9303470PubMed |
Wang, X. J., Walsh, L. P., Reinhart, A. J., and Stocco, D. M. (2000). The role of arachidonic acid in steroidogenesis and steroidogenic acute regulatory (StAR) gene and protein expression. J. Biol. Chem. 275, 20 204–20 209.
| The role of arachidonic acid in steroidogenesis and steroidogenic acute regulatory (StAR) gene and protein expression.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXkslags7o%3D&md5=9f777c4ce446dfd76688b2953addfa6cCAS |
Wani, N. A. (2002). In vitro maturation and in vitro fertilization of sheep oocytes. Small Rumin. Res. 4, 89–95.
Waterman, M. R. (1994). Biochemical diversity of cAMP-dependent transcription of steroid hydroxylase genes in the adrenal cortex. J. Biol. Chem. 269, 27 783–27 786.
| 1:CAS:528:DyaK2cXmsVOht7w%3D&md5=82086d255eab1486580001b018a8ed4bCAS |
Wathes, C. D., Abayasekara, D. R. E., and Aitken, R. J. (2007). Polyunsaturated fatty acids in male and female reproduction. Biol. Reprod. 77, 190–201.
| Polyunsaturated fatty acids in male and female reproduction.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXot1OnsL0%3D&md5=f9f27869c67f75e6ac523b7c248cc21dCAS |
Wehrman, M. E., and Welsh, T. H. Wehrman, M. E., and Welsh, T. H. (1991). Diet-induced hyperlipidemia in cattle modifies the intrafollicular cholesterol environment, modulates ovarian follicular dynamics and hastens the onset of postpartum luteal activity. Biol. Reprod. 45, 514–522.
| Diet-induced hyperlipidemia in cattle modifies the intrafollicular cholesterol environment, modulates ovarian follicular dynamics and hastens the onset of postpartum luteal activity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3MXlvVWqu7s%3D&md5=43bfbca34ead2f98307641fe7cd5ec00CAS | 1782301PubMed |
Williams, G. L., and Stanko, R. L. (2000). Dietary fats as reproductive nutraceuticals in beef cattle. Available: http://www.asas.org/JAS/symposia/proceedings/0915.pdf. Accessed February 2011.
Yilmaz, M., Davis, E., and Simmen, R. C. M. (2004). Estimation of (co)variance components for reproductive traits in Angus beef cattle divergently selected for blood serum IGF-I concentration. J. Anim. Sci. 82, 2285–2292.
| 1:CAS:528:DC%2BD2cXmtFeltLY%3D&md5=ef06776762f2192933c66b5142210678CAS |
Zanini, S. F., Torres, C. A., Bragagnolo, N., Turatti, J. M., Silva, M. G., and Zanini, M. S. (2003). Evaluation of the ratio of omega-6 : omega-3 fatty acids and vitamin E levels in the diet on the reproductive performance of cockerels. Arch. Tierernahr. 57, 429–442.
| Evaluation of the ratio of omega-6 : omega-3 fatty acids and vitamin E levels in the diet on the reproductive performance of cockerels.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXhsVekur8%3D&md5=d330ed0d400dc728f8f4922d59a5f3d3CAS | 14982322PubMed |
