Volume 98, Issue 5, May 2015, Pages 3086–3099
- * Department of Animal Reproduction, Faculdade de Medicina Veterinaria e Zootecnia, Universidade de São Paulo (FMVZ-USP), Rua Prof. Orlando Marques de Paiva, 87, 05508-000 São Paulo, SP, Brazil
- † Department of Veterinary Medicine, Departamento de Medicina Veterinaria (DMV), Universidade Federal de Lavras, 37200-000, Lavras, MG, Brazil
- ‡ EMBRAPA Gado de Leite, 36038-330 Juiz de Fora, MG, Brazil
- Received 15 September 2014, Accepted 3 December 2014, Available online 25 February 2015
Abstract
The
effects of different dietary energy levels [100 and 170% for
maintenance (M) and high energy (1.7M), respectively] on metabolic,
endocrine, and reproductive parameters were evaluated in nonlactating Bos indicus (Gir; n = 14) and Bos taurus
(Holstein; n = 14) cows submitted to ultrasound-guided ovum pick-up
followed by in vitro embryo production. The oocyte donor cows were
housed in a tiestall system and fed twice daily (0800 and 1600 h).
Twenty-one days before the beginning of the experiment, the animals were
fed with a maintenance diet for adaptation followed by the experimental
diets (M and 1.7M), and each cow underwent 9 ovum pick-up procedures 14
d apart. The recovered oocytes were cultured in vitro for 7 d. We
measured glucose and insulin concentrations and performed glucose
tolerance tests and the relative quantification of transcripts (PRDX1, HSP70.1, GLUT1, GLUT5, IGF1R, and IGF2R)
from the oocytes recovered at the end of the experimental period. No
interactions were observed between the effects of genetic groups and
dietary energy level on the qualitative (viable oocytes, quality grade,
and oocyte quality index) and quantitative (oocytes recovered) oocyte
variables. There were no effects of dietary energy level on the
qualitative and quantitative oocyte variables. However, Bos indicus
cows had greater numbers of recovered structures, viable oocytes, and A
and B oocyte grades as well as better oocyte quality index scores and
lower DNA fragmentation rates compared with Bos taurus donors.
In vitro embryo production (cleavage and blastocyst rates and number of
embryos) was similar between diets, but the 1.7M diet reduced in vitro
embryo production in Bos indicus cows after 60 d of treatment. Moreover, Bos indicus cows on the 1.7M diet showed lower transcript abundance for the HSP70.1, GLUT1, IGF1R, and IGF2R
genes. All cows fed 1.7M diets had greater glucose and insulin
concentrations and greater insulin resistance according to the glucose
tolerance test. In conclusion, increasing dietary energy did not
interfere with oocyte numbers and quality, but the 1.7M diet reduced in
vitro embryo production in Bos indicus cows after 60 d of treatment. Finally, Bos indicus cows had greater oocyte quality, greater numbers of viable oocytes and greater in vitro embryo yield than Bos taurus.
Key words
- bovine;
- nutrition;
- oocyte;
- ovum pick-up–in vitro production;
- cattle
Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
