Effects of perinatal nutrition on lactational performance, metabolic and hormonal profiles of dairy goats and respective kids

摘要

The aim of the present work was to monitor the effect of a high versus a low diet on the metabolic and hormonal profiles of dairy goats and the progeny. Starting from the last month of pregnancy, 14 goats were randomly allocated to two groups: Low Diet (LD) and High Diet (HD) that received a diet that covered 80% and 140% of their energy requirements, respectively. Blood samples were taken from all goats, at -4, -3, -2, -1, 0 (partum), +1, +2, +3, +4, and +5 weeks from delivery. Blood samples were collected from goat kids on the day of birth prior to colostrum feeding (week 0) and then at 1, 2, 3, 4 and 5 weeks of age. Blood samples were assayed for their content of: urea, triglycerides, cholesterol, total protein, albumin, calcium and inorganic phosphorus, globulin, non-esterified fatty acids (NEFA), beta-hydroxy butyric acid (BHBA), insulin, free triiodothyronine (fT), free thyroxine (fT), leptin and prolactin (PRL). Kids' live weights (LW) and growth rate were not affected by maternal nutrition. Milk yield was significantly (P <0.05) higher in the HD goats. A significant (P <0.001) effect of time was noted on plasma glucose, total protein, albumin, globulin and phosphorus concentrations. Concentration of plasma NEFA, BHBA, triglycerides and calcium were significantly (P <0.01, P <0.05, P <0.001 and P <0.05, respectively) higher in the LD goats than those in HD goats. Plasma insulin and PRL levels were higher in the HD goats than those in LD goats (P <0.05 and P <0.01, respectively). Plasma leptin level were lower on the day of partum (P <0.05). Plasma glucose and insulin concentrations were higher in the HD kids than those in LD kids (P <0.01) while plasma NEFA and triglycerides concentrations were higher (P <0.05) in the LD kids than in the HD kids. Plasma leptin concentrations increased (P <0.001) soon after kids began suckling but its values were not influenced by the dietary treatments. The thyroid hormones increased over time and their values were significantly higher in HD kids than those in LD kids at week 5. Our results showed that perinatal nutrition affects goats' and kids' metabolic and hormonal profiles; however this did not have an effect on foetal and kids' growth. Nutrient restriction during pregnancy shifted nutrient partitioning towards the uterus to sustain foetal growth. This homeorhetic adaptation was continued during early lactation; however, it was not sufficient to sustain milk production.