Efficiency of in vitro embryo production of yak (Bos grunniens) cultured in different maturation and culture conditions

Figures & data

Table 1. Effects of culture time on yak oocytes IVM.

		Percentage (mean±s.e) of total examined
Culture time (h)	Number of oocytes	Matured	Cleaved (2-cell)
23–24	276	51.3±7.1^c	25.6±3.9^c
25–26	293	78.4±5.3^a	43.7±5.1^a
27–28	284	84.3±6.4^a	46.5±4.7^a
29–30	269	72.5±4.9^b	36.4±3.5^b
Note: Values with different superscripts are significantly different (P<0.05).

Table 2. Effects of different hormons (FSH, LH and E₂) added to culture media on IVM and development into 2-cell of yak oocytes.

		Percentage (mean±s.e) of total examined
Hormones	Number of oocytes	Matured	Cleaved (2-cell)
0.5 mg/L FSH + 1 mg/L E2	531	76.0±3.0^b	32.5±1.8^b
5.0 mg/L LH + 0.5 mg /L FSH	498	13.5± 2.7^d	0^d
5.0 mg/L LH + 1 mg/L E2	501	65.3±4.2^c	21.8±4.0^c
5.0 mg/L LH + 0.5 mg/L FSH + 1 mg/L E2	525	82.4±1.9^a	43.5±3.5^a
Note: Values with different superscripts are significantly different (P<0.05).

Table 3. Effects of different serum on yak oocytes IVM, fertilisation and development.

			Percentage (mean±s.e) of total examined
Serum	Hormone	Number of oocytes	Matured	Cleaved (2-cell)	Morulae
FCS	+	379	87.2±4.3^a	63.4±4.7^a	27.1±1.8^a
	−	342	21.3±4.0^c	7.1±3.8^c	3.6±1.3^c
ECS	+	338	81.5±3.4^a	61.7±5.3^a	25.3±4.2^a
	−	357	69.8±2.2^b	39.6±3.1^b	10.5±3.6^b
Note: Values with different superscripts are significantly different (P<0.05).

Table 4. Effects of different culture medium on yak early embryo in vitro development.

		Percentage (mean±s.e) of total examined
Culture system	Number of Cleavage (2-cell)	Morulae	Blastocysts	Hatched blastocysts
Co-culture with GC	242	28.7±2.1^a	10.6±2.5^a	4.3±0.5^a
Co-culture with BOEC	239	27.6±3.5^a	8.7±3.2^a	2.6±0.3^a
TCM199 + 10% FCS absence GC and BOEC	229	0^c	0^c	0^c
SOFaa with 3 mg/ml BSA	217	11.0±2.7^b	3.0±2.6^b	0.8±0.2^b
Note: Values with different superscripts are significantly different (P<0.05).

Figure 1.   The photo of oocyte and embryo in different development stage for yak.

A: Immature oocyte (d −1); B: Matured oocyte (d 0); C: 2-cell embryo (d 1–2); D: 4-cell embryo (d 2); E: 8-cell embryo (d 2–3); F: 8–16 cell embryo (d 3); G: >16 cell embryo (d 3–4); H: Compact Morula (d 4–5); I: Compact morula-early blastocyst (d 5–6); J: Early blastocyst (d 6–7); K: Blastocyst (d 7–8); L: Hatching blastocyst (d 8–9).