Glucose and glycogen levels in piglets that differ in birth weight and vitality

Abstract

In the pig, intrauterine crowding can greatly affect postnatal characteristics, among which birth weight and locomotion. In a previous study, we discovered that piglets with a low birth weight/low vitality (L piglets) have a reduced motor performance compared to piglets with a normal birth weight/normal vitality (N piglets). A possible explanation is that L piglets lack the energy to increase their motor performance to the level of that of N piglets. Blood glucose levels (GLU) and glycogen concentrations in skeletal muscle of the front (GLY_FRONT) and hind leg (GLY_HIND) and the liver (GLY_LIVER) at birth and during the first 96 h postpartum were compared between L and N piglets. GLU at birth was the same for both groups. After birth, GLU immediately increased in N piglets, whereas it only increased after 8 h in L piglets. L piglets showed a lower GLY_HIND at birth and did not use this glycogen during the first 8 h postpartum, while N piglets showed a gradual depletion. GLY_LIVER at birth was 50% lower for L piglets and was unused during the studied period while N piglets consumed half of their GLY_LIVER during the first 8 h. Based on these results, it is possible that lower glycogen concentrations at birth, the delayed increase in GLU and the lower use of glycogen during the first 8 h after birth negatively affect motor performance in L piglets. However, based on this study, it is unclear whether the low mobilization of glycogen by L piglets is a consequence, rather than a cause of their lower motor performance.

Keywords: Animal nutrition; Animal product; Energy; Intrauterine crowding; Liver; Livestock management; Skeletal muscle; Sus scrofa; Veterinary medicine.

Fig. 1

Blood glucose levels. n = 56. N = piglets with a normal birth weight/normal vitality; L = piglets with a low birth weight/low vitality. A normal birth weight is defined as a birth weight within the limits of the mean birth weight of the litter ±SD, a normal vitality score as 3 or 4 out of 4 (based on activity and respiration). A low birth weight is defined as a birth weight < the mean birth weight of the litter - SD, a low vitality score as 1 or 2 out of 4 (based on activity and respiration). All values are mean ± SD. Significant differences (linear mixed models, p ≤ 0.05) are indicated by different letters.

Fig. 2

Glycogen concentration in skeletal muscle. A. Glycogen concentration front leg (n = 32). B. Glycogen concentration hind leg (n = 32). N = piglets with a normal birth weight/normal vitality; L = piglets with a low birth weight/low vitality. A normal birth weight is defined as a birth weight within the limits of the mean birth weight of the litter ±SD, a normal vitality score as 3 or 4 out of 4 (based on activity and respiration). A low birth weight is defined as a birth weight < the mean birth weight of the litter - SD, a low vitality score as 1 or 2 out of 4 (based on activity and respiration). All values are mean ± SD. Significant differences (linear mixed models, p ≤ 0.05) are indicated by different letters.

Fig. 3

Glycogen concentration in the liver. n = 32. N = piglets with a normal birth weight/normal vitality; L = piglets with a low birth weight/low vitality. A normal birth weight is defined as a birth weight within the limits of the mean birth weight of the litter ±SD, a normal vitality score as 3 or 4 out of 4 (based on activity and respiration). A low birth weight is defined as a birth weight < the mean birth weight of the litter - SD, a low vitality score as 1 or 2 out of 4 (based on activity and respiration). All values are mean ± SD. Significant differences (linear mixed models, p ≤ 0.05) are indicated by different letters.