Table 2.
Shifts in Weddell seal hematological parameters and muscle biochemistry associated with lactation.
| Skip-breeders | Post-partum females | Effect of reproductive class | ||||
|---|---|---|---|---|---|---|
| Early-summer (lactation period) | Late-summer | Early-summer beginning lactation (7 dpp) | Early-summer end lactation (35 dpp) | Late-summer post-weaning (95 dpp) | LME F-statistic; P-value | |
| Hematology | ||||||
| Hematocrit (%) | 62.8 ± 0.6a (63) | 61.1 ± 0.5ab (84) | 56.2 ± 1.6c (17) | 60.4 ± 0.4b (64) | 57.0 ± 0.6c (61) | F4,181 = 18.7; P < 0.001* |
| MCHC (%) | 39.3 ± 0.3ab (63) | 39.8 ± 0.2a (83) | 39.9 ± 0.7ab (15) | 39.1 ± 0.2ab (64) | 38.8 ± 0.2b (60) | F4,151 = 2.6; P = 0.039* |
| Red Blood Cells (106 μL−1) | 3.94 ± 0.06a (48) | 3.78 ± 0.06a (82) | 3.63 ± 0.17ab (12) | 3.83 ± 0.05a (64) | 3.54 ± 0.05b (55) | F4,168 = 7.5; P < 0.001* |
| Plasma Volume (L) | 22.8 ± 0.8a (60) | 22.7 ± 0.6a (82) | 27.7 ± 1.0b (16) | 21.7 ± 0.5a (63) | 24.9 ± 0.6b (56) | F4,123 = 17.4, P < 0.001* |
| Plasma Volume (%LBM) | 9.33 ± 0.16a (56) | 9.70 ± 0.14b (80) | 10.44 ± 0.19bcd (15) | 11.32 ± 0.19c (62) | 10.54 ± 0.15d (55) | F4,144 = 24.1, P < 0.001* |
| Blood Volume (L) | 61.9 ± 2.1a (60) | 58.1 ± 1.5b (82) | 62.9 ± 2.2ab (16) | 55.2 ± 1.3ab (63) | 57.1 ± 1.4ab (56) | F4,128 = 3.6, P = 0.009* |
| Blood Volume (%LBM) | 25.5 ± 0.5a (56) | 25.1 ± 0.4a (80) | 23.5 ± 0.6a (15) | 28.7 ± 0.5b (62) | 24.1 ± 0.4a (55) | F4,150 = 29.8, P < 0.001* |
| Muscle Biochemistry | ||||||
| CS (IU g wet tissue−1) | 16.0 ± 0.6ab (47) | 15.3 ± 0.4ab (64) | 13.3 ± 1.3bc (14) | 12.9 ± 0.5c (41) | 17.4 ± 0.7a (27) | F4,152 = 8.3, P < 0.001* |
| HOAD (IU g wet tissue−1) | 29.2 ± 1.4ab (48) | 26.1 ± 1.1ab (65) | 22.9 ± 2.4ab (14) | 24.7 ± 1.5a (43) | 30.7 ± 2.0b (29) | F4,135 = 3.1, P = 0.018* |
| LDH (IU g wet tissue−1) | 693.0 ± 19.6a (48) | 506.9 ± 13.6bc (65) | 592.8 ± 29.0b (14) | 509.3 ± 20.7bc (43) | 459.7 ± 17.7c (29) | F4,135 = 24.9, P < 0.001* |
| LDH:CS | 46.1 ± 2.1a (47) | 35.3 ± 1.7b (64) | 49.9 ± 5.2a (14) | 42.4 ± 2.7ab (41) | 27.3 ± 1.6c (27) | F4,154 = 13.9, P < 0.001* |
| CS:HOAD | 0.58 ± 0.02 (47) | 0.63 ± 0.02 (64) | 0.60 ± 0.04 (14) | 0.60 ± 0.04 (41) | 0.61 ± 0.03 (27) | F4,164 = 0.9, P = 0.457 |
*Asterisk denotes significant difference among reproductive classes.
Mean ± SE Weddell seal hematology (hematocrit, mean corpuscular hemoglobin concentration (MCHC), red blood cell counts), plasma and blood volume (as Liters or scaled to lean body mass, LBM), and longissimus dorsi skeletal muscle aerobic (Citrate synthase, CS; β-Hydroxyacyl CoA dehydrogenase, HOAD) and anaerobic (Lactate dehydrogenase, LDH) enzyme activities in skip-breeding and post-partum females across the austral summer lactation and post-weaning periods. Statistical significance was detected using Linear Mixed-Effect models and post-hoc comparisons with Bonferroni correction. Sample size for each measure is shown in parentheses and different letters (a,b,c) indicate significant differences in physiological parameter between reproductive classes.