Role of glucose, fatty acids and protein in regulation of testicular growth and secretion of gonadotrophin, prolactin, somatotrophin and insulin in the mature ram.
This study tested whether the effects of nutrition on gonadotrophin secretion and testicular growth in mature rams are due to increases in the supply of glucose, fatty acids (FA) or amino acids. Responses to protein (casein) and glucose, alone or in combination, were compared with responses to lupin grain and responses to a combination of protein, glucose and FA (acetate, propionate and vegetable oil). Glucose and casein were infused intra-abomasally whereas lupins and FA were added to the diet. Lupin feeding decreased blood growth hormone (GH) concentrations, but increased pulsatile luteinizing hormone (LH) secretion and increased the concentrations of follicle-stimulating hormone (FSH), prolactin, glucose and insulin. These effects were associated with testicular growth. Glucose or casein increased insulin concentrations and decreased GH concentrations, but did not affect gonadotrophins or testicular growth. There was no synergism between casein and glucose. Responses elicited by adding FA to the glucose+casein treatment were similar to those observed with lupins. In conclusion, the reproductive axis does not seem to be closely linked with dietary intakes of amino acids or with circulating concentrations of glucose, insulin or GH. However, the energetic components of the diet, particularly the fatty acids, appear to play a key role in the reproductive responses to changes in nutrition.
Boukhliq
R
R
Faculty of Agriculture (Animal Science), The University of Western Australia, Nedlands.
Martin
G B
GB
White
C L
CL
Blackberry
M A
MA
Murray
P J
PJ
D000704:Analysis of Variance; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism; D001835:Body Weight; D002364:Caseins / Q000008:administration & dosage*; D015331:Cohort Studies; D002149:Energy Intake / Q000502:physiology; D005227:Fatty Acids / Q000008:administration & dosage*; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism; D005947:Glucose / Q000008:administration & dosage*; D019382:Human Growth Hormone / Q000097:blood / Q000378:metabolism; D015918:Infusion Pumps, Implantable; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D008297:Male; D010940:Plant Proteins / Q000008:administration & dosage*; D011388:Prolactin / Q000097:blood / Q000378:metabolism; D011897:Random Allocation; D012756:Sheep / Q000254:growth & development / Q000378:metabolism*; D013737:Testis / Q000254:growth & development*; D013997:Time Factors
D001786:Blood Glucose; D002364:Caseins; D005227:Fatty Acids; D007328:Insulin; D010940:Plant Proteins; D019382:Human Growth Hormone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D005947:Glucose