Effects of dry matter and energy intake on quality of oocytes and embryos in ruminants

Abstract

The success of herd fertility involves the development of healthy follicles, viable oocytes and embryos capable of establishing and maintaining a pregnancy. Herein we discuss how nutrition interacts with reproduction throughout follicle development and pregnancy establishment, focusing on dry matter and energy intake. High feed intake, especially associated with moderate to high body condition, before and through superstimulation protocols, natural or induced single-ovulations or before ovum pick-up has detrimental effects on the quality of oocytes or embryos. Feed restriction or high energy supply can be used strategically to obtain either more or better quality oocytes or embryos. Altering diets that provide different concentrations of circulating insulin may improve ovarian status, oocyte quality, embryo development and pregnancy establishment and maintenance. Some sources of fat can positively affect reproductive performance, such as polyunsaturated fatty acids, improving embryo quality and pregnancy. In contrast, fat supplementation in the diet may compromise embryo cryotolerance. Finally, nutrition can alter concentrations of circulating or intrafollicular hormones and metabolites and the expression of genes in cattle oocytes and embryos. For an adequate feeding program to benefit reproductive performance, factors such as genetic group, source of energy, metabolic status, physiological status and level of feed intake must be taken into account.

High body energy reserve influences extracellular vesicles miRNA contents within the ovarian follicle

“…The EVs within the follicular fluid, are one of the main communication agents, actively interact with granulosa cells and CCs, sending bioactive molecules and, thus, assisting in the oocyte’s process of acquiring competence [ 13 , 15 , 59 ]. In high BER animals, the elevated DMI appears to affect later follicular developmental stages as well as early embryonic development [ 23 , 60 ], suggesting an influence in communication between follicular compartments as early as 3–6 mm follicular diameter. Based on our data, the functional enrichment analysis for miRNAs differentially expressed between CC and EV FF in each group, we found predicted pathways related to cell proliferation, survival, growth and metabolism, which are biological processes associated with the follicular development.…”

Strategic feeding of the prepubertal Nellore heifers improves body development and increases the number of recovered oocytes, viable oocytes and embryos produced in vitro.

“…These results indicating a positive effect of diet slightly higher energy supplement that can be related a major body development and fat deposition and consequently reproductive hormone production. According to Sartori et al (2017), some management issues such as the type of diet and level of feed intake, are known to have a great impact on oocyte quality. The level of energy intake for example, can affect circulating levels of insulin and IGF-1 and 1 are directly involved in the functioning of the hypothalamic-pituitary-gonadal axis.…”

Effect of three schemes of ovum pick‐up on the follicular dynamics, gene expression, and in‐vitro developmental competence of oocytes in Sahiwal cattle

“…One study from the past revealed higher blastocyst rate in OW OPU interval which contradict our findings (Neglia et al, 2011). The possible reason may be due to species difference (Saad et al, 2019; Sartori et al, 2017), milk yield (Lucy, 2001; Walsh et al, 2011), nutrition (Lozano et al, 1998; Rabiee et al, 1999) or season (Ali & Hayder, 2008; Badinga et al, 1994). Another reason might be the synchronization of follicular population in the TW OPU interval group yielding a group of oocytes similar in developmental stage and responds consistently to the IVC following IVM and IVF (Kruip et al, 1990).…”

“…The procedure also allows follicles with diameter >2 mm to be visualized and aspirated, thereby resetting the estrous cycle and avoiding dominance of one follicle over its subordinates (Neglia et al, 2011). The outcome of OPU‐based IVEP, in terms of follicle population, oocyte recovery rate, oocyte quality and their development to morula‐blastocyst stages, is influenced by nutrition (Sartori et al, 2017), body condition score (BCS) (Dorice et al, 2019), stage of the estrous cycle (Hendriksen et al, 2004), lactation status (Baruselli et al, 2018), pregnancy status (Ratto et al, 2011), parity (Jin et al, 2016), season of the year in which OPU is carried out (Di Francesco et al, 2012) and OPU interval between consecutive OPU sessions (Konrad et al, 2017). For cattle, strategies to enhance the ovarian follicular population, the percentage of non‐atretic follicles and the COCs quality are essential for improving OPU‐IVEP efficiency.…”