Piglets
There were no significant differences between ET and AI groups (p = 0.9999) in the total piglets born nor mean litter size, whose range was from 6 to 21 and from 11 to 18 in ET and AI groups, respectively (Table 2).
Table 1. Data related to non-surgical embryo transfer procedures (donors, embryos, synchrony, pregnancy, gestation and piglets).
Embryo
|
Donors
|
Total
|
Embryos
|
Embryonic
|
Age of
|
Synchrony of
|
Pregnancy
|
Gestation
|
Total
|
transfer
|
(n)
|
embryos
|
transferred
|
embryos
|
recipient vs.
|
length
|
piglets
|
stage1
|
(+/-)2
|
procedure
|
collected (n)
|
(n)
|
(days)
|
donor (hours)
|
(days)
|
born (n)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1
|
3
|
43
|
40
|
M & B
|
6-7
|
+24
|
+
|
108
|
6
|
|
|
|
|
|
|
|
|
|
|
2
|
3
|
108
|
99
|
HB
|
7-8
|
+24
|
+
|
103
|
21
|
|
|
|
|
|
|
|
|
|
|
3
|
3
|
74
|
60
|
HB
|
8-9
|
+24
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
4
|
3
|
80
|
46
|
HB
|
6-7
|
0
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
5
|
1
|
39
|
39
|
B
|
6-7
|
0
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
6
|
2
|
56
|
50
|
HB
|
7-8
|
0
|
+
|
105
|
13
|
|
|
|
|
|
|
|
|
|
|
7
|
2
|
46
|
46
|
HB
|
7-8
|
0
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
8
|
2
|
32
|
32
|
HB
|
7-8
|
0
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
9
|
2
|
65
|
51
|
HB
|
7-8
|
0
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
10
|
2
|
41
|
41
|
HB
|
7-8
|
+24
|
-
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
11
|
2
|
52
|
47
|
HB
|
7-8
|
+24
|
-
|
-
|
-
|
- M=Morulae, B=Blastocyst, HB=Hatched Blastocyst
- (+) positive pregnancy detection at 21-26 days after onset of estrous; (-) negative pregnancy detection at 21-26 days after onset of estrous
Table 2
Piglets born, litter size mean and range, after in vivo embryo transfer or artificial insemination1
Group | Live-born piglets/Born piglets | Litter size2 | Litter size range2 |
ET | 38/40 | 13.33±7.50 | 6–21 |
AI | 42/44 | 14.67±3.51 | 11–18 |
1No statistical differences were found between groups |
2 Litter size and range considered live-born and stillborn piglets |
Table 3 discriminates the data concerning sex, birth weight and Kg per sow from piglets derived from ET and AI at birth. Thirteen males and 22 females from ET group, and 25 males and 14 females from AI group were born, and none of them presented any visible external morpho-anomalies, therefore being anatomically normal and weighing as expected. Birth weight in ET females was significantly higher than females from AI group. No differences were observed between males.
Table 3
Piglets’ sex per group, birth weight and total Kg of piglets per sow1
Group | Piglet’s sex | n | Birth weight (g) | Kg of piglets per sow |
ET | Males | 13 | 1368.00±354.10 | 17.19±5.21 |
Females | 22 | 1535.00±465.20a |
AI | Males | 25 | 1285.00±360.80 | 16.03±7.59 |
Females | 14 | 1142.00±282.40b |
a−b Values in the same column with different superscripts are significantly different (p < 0.05) |
1Stillbirths and piglets that did not survive the first 48 h were excluded from this analysis (n = 5 for for embryo transfer – ET – and artificial insemination - AI). |
Analysing the total Kg of piglets obtained at birth per sow in both groups, no significant differences were observed.
A total of 5 animals from the ET group and 5 from the AI group were excluded from this study, due to being stillbirths or dying of natural causes (i.e. low weight or crushed by the sow).
Figure 1 shows the data regarding weight and ADWG of the piglets, separated by sex. Males did not present differences in weight at birth or on days 3 and 15 of life when compared by groups. Similarly, no differences were found when ADWG was measured on days 3 and 15 between groups. However, females showed significant differences at birth weight, being heavier in ET group compared to AI, but no differences were observed on the following days. In the same way, when ADWG was compared between females, no differences were observed.
Haematological and Biochemical parameters
Data presented in the manuscript are analysed by group and sex of the piglets. An additional analysis, independent of the sex, is presented as tables in Additional File 2 (Tables S1 to S4). For more detail on mean values and to address the full haematological and biochemical analysis, data analysed by sex are also presented in the form of tables on Additional File 2 (Tables S5 to S12). Representative graphs of the principal results are shown below.
Red Blood Cells
Red blood cell count (RBC)
No significant differences were found in male piglets for RBC (Fig. 2, RBC males). On the contrary, significantly higher values were found in females from ET group compared with those derived from AI on day 3, but the difference was lost on day 15 (Fig. 2, RBC females).
Haemoglobin (Hb)
No significant differences were observed between males of ET and AI in both days (Fig. 2, Hb males). Female piglets from ET group had higher values when compared to AI, but only on day 3 (Fig. 2, Hb females).
Haematocrit (HTC)
No differences were found in male piglets born by ET or AI in both days 3 and 15 (Fig. 2, HTC males). Female ET piglets showed significant higher values at day 3 compared to those derived from AI (Fig. 2, HCT females).
Mean corpuscular volume (MCV)
No significant differences were found between male piglets born through ET or AI (Fig. 2, MCV males). Female ET piglets showed lower values on day 15 when compared to AI (Fig. 2, MCV females).
Mean corpuscular haemoglobin (MCH)
No significant differences were found in MCH from males at any time but females from ET group showed lower levels when compared to AI group, on day 15 (Additional File 2, Tables S5 and S9).
Haemoglobin concentration distribution width (HDW)
ET male piglets showed higher mean value than AI piglets on day 15 (Additional File 2, Table S5), but female ET piglets showed lower values at day 3 when compared to AI (Additional File 2, Table S9).
Reticulocytes
No differences were found in male ET vs. AI piglets (Fig. 3. Reticulocytes males), but female ET piglets showed significant lower values in comparison to AI female piglets on day 15 (Fig. 3, reticulocytes females).
Mean corpuscular volume of reticulocytes (MCVr)
Significant differences were found between both groups on day 15, with ET male piglets showing lower values than their AI counterparts (Fig. 3, MCVr males) similarly to females (Fig. 3, MCVr females). However, only females showed the same pattern on day 3, with ET females showing lower values than AI females.
Haemoglobin content of reticulocytes (CHr)
Both male and female piglets from ET group showed significant lower values than AI counterparts on day 15 (Additional File 2, Tables S1 & S4 and S5 & S9). Significant differences were found between both groups, on day 15, with ET male piglets showing lower values than their AI counterparts.
White Blood Cells
White blood cells count (WBC)
The total number of WBC was significantly higher in the ET group for both males and females on day 3 of life (Fig. 4, WBC males and females); while at day 15, these differences were only significant between females.
Neutrophils were significantly higher in males from ET group vs. AI at day 3, with no further difference (Additional File 2, Tables S6 and S10).
Lymphocytes were also significantly higher for female ET piglets, in both days 3 and 15 (Additional File 2, Tables S6 and S10).
Platelets
Platelets (PLT)
No significant differences in concentration were found between the two groups, although a trend was observed at day 3 in females (p = 0.0549), having those derived from the ET group a slightly lower value than those derived from the AI group (Additional File 2, Tables S7 and S11).
Platelecrit (PCT)
As shown in Fig. 4 (PCT, males and females), ET-males and females showed significant lower values compared to AI on days 3 and 15 of life, respectively.
Mean platelet volume (MPV)
Male ET piglets had higher values at day 15 than AI piglets (Fig. 4, MPV males). Females did not show any difference between groups (Fig. 4, MPV females).
Mean platelet mass (MPM) showed only significant differences for males derived from the ET group at day 3 regarding AI (Additional File 2, Table S7).
Platelet mass distribution width (PMDW)
The only difference found was regarding day 15, where ET male piglets had higher values than AI piglets (Additional File 2, Table S7).
Large PLT
No significant differences were found in males (Suppl. Table S7) for large PLT but females ET-derived showed lower values in comparison with females AI-derived on day 15 (Additional File 2, Table S11).
Biochemical analysis
Urea
Males did not present significant differences between groups (Fig. 5, Urea males). Conversely, females from the ET group showed values below those derived from AI, being significant different on day 15 of life (Fig. 5, Urea females).
Alkaline phosphatase (ALP)
Both males and females derived by ET showed values above AI-piglets on day 3 (Fig. 5, ALP males and females), however, only males from the ET group showed significant differences regarding the AI group. On the other hand, on day 15 of life, no significant differences were found for piglets of any sex.
Albumin (ALB)
The ALB concentrations were significantly lower on day 3 in males from the ET group compared to those from the AI group (Fig. 5, ALB males).
Total bilirubin (TBIL)
Both males and females showed a lower concentration of TBIL on day 3, with only females from the ET group showing significant differences compared to those from the AI group (Fig. 5, TBIL males and females). However, on day 15 only trend was observed (p = 0.0551) between females.
Gamma-glutamyl transferase (GGT)
Piglets (males and females) born by ET presented values above those born by AI on days 3 and 15 of life, with only males from ET showing significant differences compared to those born by AI on day 15 (Additional File 2, Tables S8 and S12).
Aspartate aminotransferase (AST)
Higher values were detected in ET-derived male piglets’ vs. AI on day 15 (Additional File 2, Table S8).
Lipases
On day 15 of life, piglets from both groups considerably decreased their concentration of lipases compared to day 3, however, only significantly differences were found in males from ET regarding those from AI (Additional File 2, Table S8).
Globulins (GLOB)
Although no significant differences were found, when the concentration of globulins was analysed, a trend was observed between males from ET having higher values compared to AI on day 15 (p = 0.0538).