Impact of supplementing feed restricted ewes’ diet with propylene glycol, monensin sodium and rumen-protected choline chloride during late pregnancy on blood biochemical indices, body condition score and body weight

Abstract

The purpose of this study was to investigate the effects of supplementing feed restricted diet with propylene glycol, monensin sodium and rumen-protected choline chloride on blood metabolic status, body condition score (BCS) and body weight of ewes in late pregnancy. At the final six weeks of pregnancy, 48 pregnant Ghezel ewes (body weight 65.53 ± 6.90 kg) were randomly allocated into six groups (n = 8) as follows: control (CG, ad libitum); feed restriction (FR, 60 % of the dry matter intake offered to CG group); feed restriction + propylene glycol (67 g/d) (FR-PG); feed restriction + propylene glycol + monensin sodium (30 mg/d) (FR-MS); feed restriction + propylene glycol + rumen-protected choline chloride (6 g/d) (FR-RPC); feed restriction + propylene glycol + monensin sodium + rumen-protected choline chloride (FR-PMC). Blood samples were collected on days 90, 117, 124, 135 and 140 of pregnancy, at lambing and days 7 and 17 after lambing for analysis of glucose, triglyceride, total cholesterol, total protein, albumin, urea, non-esterified fatty acids (NEFA), ß-hydroxybutyrate (BHBA), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and insulin using the automated biochemical analyzer and ELISA microplate reader. Body weight and BCS of ewes were recorded on days 90, 110, 130 and 140 of pregnancy, at lambing and also day 7 after lambing. All statistical analyses were carried out in a completely randomized design using the MIXED procedure of SAS v.9.3. Results of analysis revealed that pre-parturient administration of rumen-protected choline chloride combined with propylene glycol and monensin sodium elevated both pre- and postpartum concentrations of insulin (P < 0.01), glucose (P < 0.001), triglyceride (P < 0.05), total cholesterol (P < 0.05), total protein (P < 0.01) and albumin (P < 0.01) compared with other treatments. The weight and BCS loss of these ewes were also lower during the pre- and postpartum periods (P < 0.05). In this study, except for day 124 of pregnancy, when the liver enzyme levels of the choline chloride supplemented ewes were numerically low, nutritional treatments did not affect the concentrations of these enzymes at other sampling points (P> 0.05). Regarding BHBA, NEFA and urea, FR and FR-MS ewes had a higher level of these parameters than other groups (P < 0.05). It was concluded that although Ghezel ewes showed some ability in tolerating late gestational feed restriction mainly through lipomobilization, supplementing the restricted diet with rumen-protected choline chloride combined with propylene glycol and monensin sodium during the final trimester of pregnancy could result in beneficial effects on metabolic status and finally good health and condition of animals.