Earticle

This study was conducted to elucidate the effects of feeding betaine or monosodium glutamate on the growth and carcass performance of Hanwoo steers according to the fattening stage under high-temperature stress. Farms in an area where THI was 78 or higher for more than 100 days were selected, and 30 head in the early fattening stage (14-15 months of age), 30 head in the mid-fattening stage (16-18 months of age), and 30 head in the late fattening stage (24-25 months of age) were tested, and 10 head were assigned to each treatment group. The experimental group was divided into control, T1 with 96% of the amino acid compound additive and 4% betaine, and T2 with the amino acid complex additive and 4% monosodium glutamate. 50 g per head were fed every morning for a total of 5 months from May 1, 2022 to September 30. In this study, there was no effect of betaine and monosodium glutamate on the growth and rectal temperature of Hanwoo steers at each fattening stage, but monosodium glutamate had a positive effect on the increase in rib eye area and decrease in back fat thickness in steers in the late fattening stage (P<0.05). Therefore, the results of this study indicate that monosodium glutamate did not have a direct effect on the growth of fattening Hanwoo steers, but it is thought to have a positive effect on the rib eye area and back fat thickness through protein metabolism and muscle development.

Endocrine-disrupting chemicals (EDCs), such as perfluorooctanoic acid (PFOA), have been linked to adverse effects on reproductive health. However, the impact of PFOA exposure during the embryonic stage on hypothalamic gonadotropin-releasing hormone (GnRH) neurons, which are central to the regulation of the hypothalamic–pituitary axis, that controls the reproductive system, has not been investigated. In this study, immortalized embryonic mouse hypothalamic cells (mHypoE-N46) were used to evaluate alterations in GnRH expression following PFOA exposure in vitro. In addition, the expression levels of Pnx, Gpr173, BDNF, and Ntrk2—upstream signals known to regulate GnRH expression—were examined. mHypoE-N46 cells were treated with PFOA for 2-24 hours, and gene expression and protein expression levels were evaluated. PFOA significantly altered the gene expression levels of Pnx, Gpr173, BDNF and Ntrk2. GnRH expression was significantly increased at both the mRNA and protein levels. In conclusion, exposure to PFOA may perturb the upstream signaling of GnRH and may directly or indirectly affect the expression of GnRH, suggesting that PFOA may alter the GnRH regulatory network.