2,4-Thiazolidinedione in Well-Fed Lactating Dairy Goats: I. Eﬀect on Adiposity and Milk Fat Synthesis
2, 4-thiazolidinedione; goat; milk fat; metabolism
Background: In a prior experiment, treatment of goats with the putative PPARγ agonist 2,4-thiazolidinedione(2,4-TZD)didnotaﬀectmilkfatorexpressionofmilk-fatrelatedgenes. Thelack of response was possibly due to deﬁciency of vitamin A and/or a poor body condition of the animals. In the present experiment, we tested the hypothesis that PPARγ activation aﬀects milk fat synthesis in goats with a good body condition and receiving adequate levels of vitamin A. Methods: Lactating goats receiving a diet that met NRC requirements, including vitamin A, were injected with 8 mg/kg BW of 2,4-TZD (n = 6) or saline (n = 6; CTR) daily for 26 days. Blood metabolic proﬁling and milk yield and components were measured including fatty acid proﬁle. Expression of genes related to glucose and lipid metabolism was measured in adipose tissue and in mammary epithelial cells (MEC). Size of adipocytes was assessed by histological analysis. Results: NEFA, BHBA, and fatty acids available in plasma decreased while glucose increased in 2,4-TZD vs. CTR. Size of cells and expressionofinsulinsignalingandglucosemetabolism-relatedgeneswerelargerin2,4-TZDvs. CTR in adipose tissue. In MEC, expression of SCD1 and desaturation of stearate was lower in 2,4-TZD vs. CTR. Conclusions: Overall data revealed a lack of PPARγ activation by 2,4-TZD and no eﬀect on milk fat synthesis despite a strong anti-lipolysis eﬀect on adipose tissue.
Jaaf, S.; Rosa, F.; Moridi, M.; Osorio, J. S.; Lohakare, J.; Trevisi, E.; Filley, S.; Cherian, G.; Estill, C. T.; and Bionaz, M., "2,4-Thiazolidinedione in Well-Fed Lactating Dairy Goats: I. Eﬀect on Adiposity and Milk Fat Synthesis" (2019). Dairy Science Publication Database. 2145.