Study of the circulatory energy balance indicators and hepatic fat content in dromedary camel during late pregnancy and early lactation

Authors: AHMADPOUR, AMIR - Utah State University; Christensen, Rachael; ZARRIN, MOUSA - Vetsuisse Berne; MALEKJAHANI, FARNAZ - Utah State University; FARJOOD, FARHAD - Utah State University

Submitted to: Small Ruminant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2019
Publication Date: 9/9/2019
Citation: Ahmadpour, A., Christensen, R., Zarrin, M., Malekjahani, F., Farjood, F. 2019. Study of the circulatory energy balance indicators and hepatic fat content in dromedary camel during late pregnancy and early lactation. Small Ruminant Research. 179:14-20. https://doi.org/10.1016/j.smallrumres.2019.08.018.
DOI: https://doi.org/10.1016/j.smallrumres.2019.08.018

Interpretive Summary: Energy metabolism can change drastically during the time surrounding calving, also known as parturition, for cattle and other domestic livestock. However, little information is documented about the dromedary camel liver fat status during calving, such as is available for other species. Therefore, this study was conducted to document fat liver status before, near, and after calving for pastured dromedary camels. Ten female camels were followed from 60 days before to 60 days after calving. Blood was sampled at about ( ± three days) 60, 45, 30, 15, and three days before parturition, at parturition, and at the same time points during PP. Liver samples were collected through blind biopsy at about 15 days before calving, and at the same time points with blood collection during PP. No significant difference was observed for the concentration of fat in the liver between days 15 AP until 3 PP. But at 15 days following calving, a definite increase was observed for liver fat content at day 15 PP which decreased gradually afterward (P< 0.05). Liver glycogen escalated during PP after an abrupt fall at parturition (P< 0.01). Circulatory glucose, liver fat, and glycogen, all key indicators of energy status also were tracked and their individual status denoted in this study, for the most part, these key indicators were at a low level at calving, and slowly increased in serum overtime. This study, for the first time, denoted the major fluctuations in energy metabolism indicators during the physiological transition in pregnant camels. These results may be useful for comparative studies between camels and other species.

Technical Abstract: Lipid metabolism is a hallmark of energy metabolism in periparturient animals. Due to the lack of reports on fat metabolism during the transition period in camels, this study aimed to manifest the fluctuations in the fat metabolism indicators in serum and liver of camels during this period. Ten multiparous (with the parity of2.38 ± 0.56; mean ± SEM) camels with a body weight of 527.94 ± 73.46 kg were studied 60 days ante-partum (AP) until 60 days post-partum (PP). Blood was sampled at about ( ± three days) 60, 45, 30, 15, and three days before parturition, at parturition, and at the same time points during PP. Liver samples were collected through blind biopsy at about 15 days before calving, and at the same time points with blood collection during PP. No significant difference was observed for the concentration of TAG in the liver between days 15 AP until3 PP. A definite increase was observed for liver TAG content at day 15 AP, which decreased gradually afterward (P< 0.05). Liver glycogen after an abrupt fall at parturition (P< 0.01), escalated during PP. Circulatory glucose decreased 15 days AP (P= 0.03) and did not return to the previous level until the end of the investigation. Right before parturition, serum TAG was distinctly low, but ascended 15 days PP (P< 0.05) and remained quite constant until the end of the study. Total lipid, phospholipids, HDL, and VLDL, were lowest at parturition (P< 0.05), then escalated temporally. As expected the correlation between serum concentrations of NEFA andß-hydroxybutyrate (BHB) during days 15 AP and 60 PP were highly positive (0.74;P< 0.01).Although hepatic TAG content was positively correlated with serum NEFA and BHB (P< 0.01), glycogen content of the liver revealed highly negative (P< 0.01) correlation with these two serum metabolites (both-0.75). This study, for the first time, denoted the preeminent fluctuations in lipid metabolism indicators during the physiological transition in pregnant camels. These results may be useful for comparative studies between camels and other species.