Short communication: A nanoemulsified form of oil blends positively affects the fatty acid proportion in ruminal batch cultures.

Two consecutive rumen batch cultures were used to study the effect of nanoemulsified oils as a new type of supplement, on the in vitro fatty acid proportion and vaccenic acid formation. Three levels (3, 5, and 7%) of 2 different oil blends [soybean:fish oil (SF) or rapeseed-fish oil (RF)] were used. Both oil blends were used either in the raw form (SF or RF, respectively) or in the nanoemulsified form (NSF or NRF, respectively). The diets were the control (0%), which consisted of a dry total mixed ration without any supplements, the control plus 3, 5, or 7% of the SF or RF oil blend in appropriate form (raw or nanoemulsified). For each treatment, 6 incubation vessels were used. Each batch culture was incubated for 24h and conducted twice in 2 consecutive days. All supplements were calculated as a percentage of the substrate dry matter (400mg). Nanoemulsified supplements were recalculated to make sure the oil amount was equal to the raw oil supplementation levels. The results from both experiments indicated that the proportions of vaccenic acid and cis-9,trans-11 C18:2 increased when a raw oil blend was supplemented; on the other hand, no influence of nanoemulsified form of oil blend was observed on the proportion cis-9,trans-11 C18:2. Generally, supplementation with the nanoemulsified oil blends had less effect on biohydrogenation intermediates than the raw form of oil blends. However, the nanoemulsified form had a greater effect on the increase of n-3 and n-6 fatty acids. Nanoemulsified oil blends had a positive effect on decreasing the transformation rate of polyunsaturated fatty acids to saturated fatty acids in the biohydrogenation environment. Supplements of nanoemulsified oil blends tended to be more effective than supplements of raw oils in preserving a greater proportion of polyunsaturated fatty acids in the fermentation culture.

Early cleaved bovine embryos show reduced incidence of chromosomal aberrations and higher developmental potential on day 4.5 post-insemination.

The present study aimed to investigate whether the timing of the first zygotic cleavage (FZC) influences the speed of embryo development expressed by the total cell count and the rate of chromosomally aberrant embryos. Bovine embryos were produced in vitro and divided into two categories according to the timing of FZC: early cleavers (at 30 hpi; EC) and non-early cleavers (at 48 hpi; NEC). On day 4.5 pi, embryos were grouped into three classes depending on the number of blastomeres: delayed (<8 BL), normal (8-16 BL) and advanced (>16 BL). We applied fluorescence in situ hybridization (FISH) with probes for bovine chromosomes 6 and X. The only form of chromosomal imbalance observed was mixoploidy [(2n/3n; 2n/4n); 19.9%, 54/271]. Early cleavers were less often chromosomally unbalanced (13.9%, 20/144) than their NEC counterparts (26.7%, 34/127). Among embryos developing at a normal speed, the NEC embryos were more often abnormal (NEC 20/80; EC 10/79; p < 0.05). The advanced embryos were not observed among the NEC category, whereas such embryos from EC category displayed no chromosomal aberrations. The majority of embryos arrested at the 8 BL stage were of NEC category and were carriers of chromosomally abnormal blastomeres. With regard to embryonic sex, we demonstrated that although males dominate among bovine embryos developing in vitro, the incidence of mixoploidy was equal for both sexes. It can be suggested that a good-quality bovine embryo is usually an early cleaver that develops at higher speed and contains less aberrant cells. The present study also confirmed the usefulness of the FZC as a marker of embryo quality by demonstrating a significantly lower incidence of aberrations in early embryos.

Disturbances of nuclear maturation in BCB positive oocytes collected from peri-pubertal gilts.

The developmental competence (quality) of oocytes is affected by several factors linked to their intrinsic properties and also to growth and maturation environment. Donor puberty and chromosomal complement are one of the main factors influencing oocyte quality. A high rate of porcine oocytes matured in vitro is chromosomally imbalanced. Moreover, there is no published data on chromosomal aberrations in oocytes selected by the brilliant cresyl blue (BCB) test. Therefore, the aim of this study was to analyze whether BCB positive (BCB+) oocytes derived from ovaries of peripubertal gilts (prepubertal NCL and cyclic CL) differ with respect to the incidence of numerical chromosome aberrations. COCs collected from NCL and CL ovaries were selected by the BCB test. Only BCB+ oocytes were matured in vitro and subjected to FISH analysis using molecular probes for chromosome pairs 1 and 10. The rate of BCB+ oocytes was similar for both groups of ovaries (NCL 80%, CL 92%). Altogether 554 oocytes were fixed and 471 oocytes at the MII stage were analyzed cytogenetically. Diploid (2MII) and aneuploid oocytes were detected. The contribution of MII oocytes was similar for NCL (85%) and CL (90%) group. Chromosomally aberrant BCB+ oocytes accounted for 18.0% and ranged from 13.7% for CL and 22.2% for NCL ovaries. Diploidy was a predominant anomaly observed (11.2%) with a significantly higher frequency in BCB+ oocytes of pre-pubertal (16.7%) than cyclic gilts (5.6%, P < 0.05). Aneuploid oocytes occurred with similar rate in NCL (6.7%) and CL (8.5%) females. The majority of aneuploid spreads (72.2%; P < 0.01) concerned the chromosome pair 10. The overall rate of disomy (56%) and nullisomy (44.4%) was similar. We have shown that donor puberty affects the incidence of chromosomal abnormalities in porcine oocytes matured in vitro. Significantly more diploid oocytes was derived from prepubertal ovaries, whereas the frequency of aneuploidy was similar in NCL and CL gilts.

Growth hormone exerts no effect on the timing of the first zygotic cleavage in cattle.

Most of the protocols used for oocyte and embryo quality assessments are invasive and thus reduce embryo viability. Special interest has recently been placed on a search for non-invasive markers related to embryo quality. The characteristics of a non-invasive marker are met by the timing of the first zygotic cleavage (FZC). Therefore, the aim of the present study was to investigate whether growth hormone added to IVM medium influences the timing of the FZC in cattle and also the quality of resulting blastocysts. The novelty of this manuscript concerns two findings: 1) no effect of GH supplementation to IVM medium on the timing of the first zygotic cleavage in cattle, and 2) differences in the relative transcript abundance in bovine day 7.5 blastocysts derived from early and late cleaved zygotes. Cumulus-oocyte complexes aspirated from slaughterhouse ovaries were matured in TCM199 medium supplemented with growth hormone (GH+ 100 ng/ml, GH- control), inseminated, and cultured in sequential media for 7.5 d. Embryo selection was done at 30 hpi (early cleavers EC) and 48 hpi (non-early cleavers NEC). The blastocyst quality was assessed by the total and ICM:TE cell counts, dead cell index, and relative transcript abundance (RA) of five genes affecting embryo development (p66(shc), bax, bcl-2, survivin, Hsp 70.1). The results of this study showed that although GH added to the IVM medium significantly improved the quality of blastocysts on day 7.5 pi, it had no effect on the timing of the first zygotic cleavage expressed by the rate of EC zygotes. The quality of the four categories of blastocysts investigated in this study can be ranked as follows: GH+ EC, followed by GH+ NEC, and further by the GH- EC and GH- NEC embryos. It has to be mentioned, however that the quality of blastocysts derived from the NEC zygotes was significantly improved by the GH supplementation. This is particularly relevant, since those blastocysts were very few and usually characterized by an impaired morphology (e.g., presence of fragmented blastomeres, smaller size).