AUTHOR=Gómez Enrique , Murillo Antonio , Carrocera Susana , Pérez-Jánez Juan José , Benedito Jose Luis , Martín-González David , Gimeno Isabel 

TITLE=Fitness of calves born from in vitro-produced fresh and cryopreserved embryos

JOURNAL=Frontiers in Veterinary Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.1006995

DOI=10.3389/fvets.2022.1006995

ISSN=2297-1769

ABSTRACT=<p>In cattle, vitrified/warmed (V/W) and frozen/thawed (F/T), <italic>in vitro</italic>-produced (IVP) embryos, differ in their physiology and survival from fresh embryos. In this study, we analyzed the effects of embryo cryopreservation techniques on the offspring. IVP embryos cultured with albumin and with or without 0.1% serum until Day 6, and thereafter in single culture without protein, were transferred to recipients on Day 7 as F/T, V/W, or fresh, resulting in <italic>N</italic> = 24, 14, and 13 calves, respectively. Calves were clinically examined at birth, and blood was analyzed before and after colostrum intake (Day 0), and subsequently on Day 15 and Day 30. On Day 0, calves from V/W and F/T embryos showed increased creatinine and capillary refill time (CRT) and reduced heartbeats. Calves from F/T embryos showed lower PCO<sub>2</sub>, hemoglobin, and packed cell volume than calves from V/W embryos while V/W embryos led to calves with increased Na<sup>+</sup> levels. Colostrum effects did not differ between calves from fresh and cryopreserved embryos, indicating similar adaptive ability among calves. However, PCO<sub>2</sub> did not decrease in calves from V/W embryos after colostrum intake. Serum in culture led to calves with affected (<italic>P</italic> &lt; 0.05) temperature, CRT, HCO<inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula>, base excess (BE), TCO<sub>2</sub>, creatinine, urea, and anion gap. On Day 15, the effects of embryo cryopreservation disappeared among calves. In contrast, Day 30 values were influenced by diarrhea appearance, mainly in calves from V/W embryos (i.e., lower values of TCO<sub>2</sub>, HCO<inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula>, and BE; and increased glucose, anion gap, and lactate), although with no more clinical compromise than calves from fresh and F/T embryos. Diarrhea affected PCO<sub>2</sub> and Na<sup>+</sup> in all groups. Embryo cryopreservation, and/or culture, yield metabolically different calves, including effects on protein and acid–base metabolism.</p>