Dietary Energy Levels Affect Growth Performance through Growth Hormone and Insulin-Like Growth Factor 1 in Yak (Bos grunniens)

Abstract

The objective of this study was to investigate the effects of different dietary energy levels on serum concentrations of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), as well as gene expression of their associated binding proteins and receptors in yak. Fifteen adult male yaks with BW of 276.1 ± 3.5 kg were allotted in three dietary groups and were fed with low (LE), medium (ME), and high energy (HE) level diet having different NEg of 5.5 MJ/kg, 6.2 MJ/kg, 6.9 MJ/kg, respectively. The effects of these treatments on ADG, BW, ADFI, and feed conversion ratio were significant (p < 0.05) throughout the experimental period. Serum GH concentration decreased (p < 0.05) with an increase in dietary energy level on d 30 and d 60. While IGF-1 concentration was higher (p < 0.05) in ME group, as compared to LE and HE groups on d 60. The expression level of growth hormone receptor (GHR) was decreased (p < 0.001) and IGF-1 was increased with the increase in the dietary energy level. The relative expression of insulin-like growth factor binding protein 3 (IGFBP-3) was higher (p < 0.001) in ME and HE groups, except the LE group. In conclusion, our findings provide a first insight into the combined effect of GH and IGF-1 in controlling the metabolism and productivity of yak. It also showed that medium energy level diet contributed to promote growth performance of yak during the cold season.

Effects of Dietary Energy Levels on Rumen Fermentation, Microbial Diversity, and Feed Efficiency of Yaks (Bos grunniens)

“…The growth performance of yaks has been previously reported ( Yang et al, 2019 ). The final body weights of YM and YH group animals were significantly higher than those in the YL group ( P < 0.05).…”

“…Acetate and butyrate are used for fat synthesis and energy supply, while propionate is the main source of glucose for ruminants ( Den Besten et al, 2013 ). We recorded high feed efficiency in yaks from YM and YH groups, which could be explained by a significant increase in concentrations of VFA with the resulting increase of metabolizable energy content of the feed ( Yang et al, 2019 ). High concentrations of acetate, propionate, and valerate in rumen of high milk-producing Holstein dairy cows were reported ( Xue et al, 2019 ).…”

“…The animals were fed ad libitum twice daily at 08:00-09:00 and 17:00-18:00 with a total of 2.45-kg concentrate and 5.75-kg roughage mixtures with free access to water. The orts were recorded to calculate average daily feed intake (ADFI), and ADFI was determined as the total feed intake/60 (Yang et al, 2017(Yang et al, , 2019. Animals of each group were weighed before the morning feeding on the first and 60th days of the trial; feed efficiency was calculated as average daily gain/ADFI during the experimental period.…”

Predicting the Productive and Reproductive Performance of Egyptian Baladi Calves as a Response to Growth Rate Associated With Growth Hormone Level

“…Moreover, Renaville et al (2002) reported that GH synthesized in the pituitary gland and acts directly on liver and adipose tissue to regulate gluconeogenesis, proteosynthesis, lipogenesis, lipolysis, and insulin secretion by binding to growth hormone receptor (GHR). Meanwhile, the existence of the axis between GH and IGF-1 has played a vital role in the regulation of metabolism and GHR combines with GH to stimulate a series of metabolic activities by producing IGF-1 in the target tissues, especially in liver (Yang et al, 2019).…”

“…After clotting at room temperature, sera were separated by centrifugation at 1,800 g for 20 min and transferred to plastic tubes. Sera were stored at -20 ºC for subsequent GH concentration analysis by using a commercial ELISA kit (Beijing Sino-UK Institute of Biological Technology, Beijing, China) according to Yang et al (2019). Serum glucose concentration was measured by the glucose/oxidase method using a commercial kit (Biolabo, Glucose GOD-PAP, Cat.…”