In vitro embryo production in buffaloes: from the laboratory to the farm

Abstract

Transvaginal follicular aspiration technique together with in vitro embryo production are the biotechnological alternatives currently available to support genetic improvement breeding programs in buffalo species. However, aspects related to animal management, lack of knowledge of the metabolic needs and biochemical peculiarities of gametes and embryos, as well as the reproductive physiology characteristics have hampered progress in the results. Despite the low availability of good quality oocytes collected after OPU in donors as a physiological characteristic of buffalo species, high rates of oocyte maturation, modest embryo cleavage, blastocyst production and pregnancy rates after transvaginal embryo transfer in recipients could be obtained in buffalo in vitro embryo production programs. The results of implementing an in vitro embryo production program in buffaloes in the northern region of Pará state, Brazil, and results published by other groups demonstrate the feasibility of implementing this biotechnology in the routine of breeding programs. Nevertheless, in order to achieve better and consistent results, it is necessary to deepen the knowledge on the peculiarities of reproductive biology in this specie. Selection of donor animals based on ovarian size and ovarian follicular reserve and on the rate of blastocyst production is presented as an effective alternative to increase the efficiency of the in vitro embryo production technique applied to the buffalo species.

Impact of in vitro fertilization by refrigerated versus frozen buffalo semen on developmental competence of buffalo embryos

“…Average follicle punctured per donor varied from 5.6 to 8.7 which is close to numbers found by Sá et al (2009) , Gasparrini et al (2014) and Pereira (2015) . A higher number of follicles per donor (from 12.6 to 15.6) was reported by Ferraz et al (2015) , Ohashi et al (2017) and Marin et al (2019) selecting donors with higher number of follicles, reported an average 13.6 follicle per female. Average number of recovered oocytes per donor and session varied from 4.2 to 6.5 above the number (n=3.7) found by Pereira (2015) , while Ohashi et al (2017) and Marin et al (2019) , using a population of donors with higher number of follicles found an average of 7.8 and 10.2 oocytes per donor, respectively.…”

“…A higher number of follicles per donor (from 12.6 to 15.6) was reported by Ferraz et al (2015) , Ohashi et al (2017) and Marin et al (2019) selecting donors with higher number of follicles, reported an average 13.6 follicle per female. Average number of recovered oocytes per donor and session varied from 4.2 to 6.5 above the number (n=3.7) found by Pereira (2015) , while Ohashi et al (2017) and Marin et al (2019) , using a population of donors with higher number of follicles found an average of 7.8 and 10.2 oocytes per donor, respectively. Oocyte recovery rate obtained in the present study (68 to 81%) was above that reported by Sá et al (2009) (57.7%) and Pereira (2015) (35%).…”

“…Efficiency (OPU/IVEP) in buffalo is necessary to enhance the use of superior genetic material. OPU can be performed on prepubertal, anestrus, cycling and even pregnant buffalo, however, some anatomophysiological peculiarities, such as lower weight and size of ovaries compared to cows ( Vitoria, 1997 ), lower total primordial follicular number in buffalo when compared to cows ( Danell, 1987 ; Erickson, 1966 ; Baruselli et al, 1997 ; Gimenes et al, 2009 ; Campanile et al, 2010 ; Santos et al, 2013 and Liang et al, 2016 ), greater follicular rate atresia in buffaloes ( Le Van Ty et al, 1989 ; Ocampo et al, 1994 ; Perera, 2011 ; Santos et al, 2013 ), low eligibility rate for buffalo oocytes (38.4%) for the culture due to less compaction and fewer cumulus layers ( Ohashi et al, 2003 ; Gimenes et al, 2010 ; Marin et al, 2019 ) and the seasonality effects on the quality of oocytes ( Gimenes et al, 2010 ; Gasparrini, 2018 ) are limiting factors for in vitro embryo production (IVEP) in buffalo species ( Salzano et al, 2018 ; Baruselli et al, 2020 ).…”

Expresión génica en células de granulosa bovinas de folículos en crecimiento

“…La comparación de los genes diferencialmente expresados muestra como ninguno de los genes mayormente expresados tienen una función conocida sobre la foliculogénesis o la maduración de los oocitos, es importante mencionar que aquellos genes hay subexpresión, todos están relacionados con la cadena respiratoria, habrá que demostrar que esa diferencia pueda ser una explicación a lo observado por Marin et al, sobre el incremento en la producción de radicales libres en los cultivos de embriones in vitro de búfalo y la necesidad de adicionar antioxidantes para incrementar las tazas de producción de embriones in vitro (14).…”

“…6/8 Encontrar la expresión de genes asociados a la unión, está de acuerdo con la naturaleza fisiológica de los folículos que en ese tamaño son un tejido proliferativo que para su desarrollo necesita una gran cantidad de RNA mensajeros de señales (18) para cumplir su función: inmediata de ovulación e indirectamente un oocito competente para formar un embrión. Otros trabajos donde hay comparación de expresión diferencial en folículos informan que existen en los búfalos 110 genes diferencialmente expresados pertenecientes a 14 vías metabólicas y que para las vacas se encontraron 446 genes que pertenecían a 10 vías metabólicas (14).…”