Homocysteine involvement in pregnancy establishment in buffalo cows (Bubalus bubalis)

The decline in reproductive efficiency is the most important cause of economic losses in buffaloes as well as in all ruminants, especially in intensive farming systems. In humans, ruminants and other species, sulphur-containing amino acids such as homocysteine (Hcy) are involved in maternal and embryo metabolism in early stages after fertilization, because they play critical roles in metabolic-processes like oxidative stress and transmethilations. The aim of this study was to investigate homocysteine in pregnancy establishment in buffalo. 35 animals, out of the buffalo herd subjected to a synchronization and artificial insemination (AI) program, were enrolled in this study and were divided ex post, in three groups: pregnant (P, n=14), not pregnant (NP, n=14) and with embryo mortality (EM, n=7). Pregnancy and embryo viability were performed on 28, 40 and 56 days from AI by ultrasonography and by pregnancy associated glycoproteins (PAG) determination. Blood samples were taken at 0, 14, 21, 28 and 56 days from AI to analyse Hcy. Hcy levels were lower in NP buffaloes (mean 1.023 ± 0.30 µM) than in P(mean 1.64 ± 0.38 μM) and EM (mean 1.58 ± 0.43 μM) (P< 0.05) at all time points. No significant differences emerged between P and EM. Hcy levels did not change significantly in any group throughout the experimental period. Inter-group differences suggested that in buffalo cows Hcy levels should be high, like those detected in P and EM groups, in order to achieve fertilization after AI. Cows with low Hcy levels, like NP group, have less chance of establishing pregnancy. In this contest, Hcy might be a promising indicator of good maternal metabolic environment to support conceiving and the better comprehension of its metabolic relevance suggest new insights to obtain pregnancy establishment.