Identification of heat shock protein gene expression in hair follicles as a novel indicator of heat stress in beef calves

Abstract

Heat shock proteins (HSPs) consist of highly preserved stress proteins that are expressed in response to stress. Two studies were carried out to investigate whether HSP genes in hair follicles from beef calves can be suggested as indicators of heat stress (HS). In study 1, hair follicles were harvested from three male Hanwoo calves (aged 172.2 ± 7.20 days) on six dates over the period of 10 April to 9 August 2017. These days provided varying temperature–humidity indices (THIs). In study 2, 16 Hanwoo male calves (aged 169.6 ± 4.60 days, with a BW of 136.9 ± 6.23 kg) were maintained (4 calves per experiment) in environmentally controlled chambers. A completely randomized design with a 2 × 4 factorial arrangement involving two periods (thermoneutral: TN; HS) and four THI treatment groups (threshold: THI = 68 to 70; mild: THI = 74 to 76; moderate THI = 81 to 83; severe: THI = 88 to 90). The calves in the different group were subjected to ambient temperature (22°C) for 7 days (TN) and subsequently to the temperature and humidity corresponding to the target THI level for 21 days (HS). Every three days (at 1400 h) during both the TN and HS periods, the heart rate (HR) and rectal temperature (RT) of each individual were measured, and hair follicles were subsequently collected from the tails of each individual. In study 1, the high variation (P < 0.0001) in THI indicated that the external environment influenced the HS to different extents. The expression levels of the HSP70 and HSP90 genes at the high-THI level were higher (P = 0.0120, P = 0.0002) than those at the low-THI level. In study 2, no differences in the THI (P = 0.2638), HR (P = 0.2181) or RT (P = 0.3846) were found among the groups during the TN period, whereas differences in these indices (P < 0.0001, P < 0.0001 and P < 0.0001, respectively) were observed during the HS period. The expression levels of the HSP70 (P = 0.0010, moderate; P = 0.0065, severe) and HSP90 (P = 0.0040, severe) genes were increased after rapid exposure to heat-stress conditions (moderate and severe levels). We conclude that HSP gene expression in hair follicles provides precise and accurate data for evaluating HS and can be considered a novel indicator of HS in Hanwoo calves maintained in both external and climatic chambers.

Heat-Shock Proteins Gene Expression in Peripheral Blood Mononuclear Cells as an Indicator of Heat Stress in Beef Calves

“…In addition, an increase in HSP70 expression was observed after exposure to heat at 42 • C for 4 h in mammary epithelial cells [14] corroborating this study. As previously reported, the heart rate and rectal temperature as heat-stress indicators increased in each group under the HS conditions (moderate and severe levels) [19,37]. In the current study, expression of the HSP70 gene was increased under rapid exposure to severe HS conditions.…”

“…A completely randomized design with four THI treatment groups (threshold, mild, moderate and severe) was used-Calves were subjected to ambient temperature (22 • C) for 7 days (TN) in the adaptation period one week prior to the beginning of the experiment, after which the temperature and humidity in the chambers were raised to each already defined THI level for 21 days (HS). The four THI treatments were defined as threshold (22 to 24 • C, 60% RH: THI = 68 to 70), mild (26 to 28 • C, 60% RH: THI = 74 to 76), moderate (29 to 31 • C, 80% RH: THI = 81 to 83) and severe (32 to 34 • C, 80% RH: THI = 88 to 90) stress levels [19]. Temperature and RH inside the chamber were recorded at intervals of 1 s using two sensors (SHT7×, Sensirion AG, Laubisruetistrasse 508, 712 Staefa ZH, Switzerland).…”

The effects of vitamin A supplementation during late-stage pregnancy on longissimus dorsi muscle tissue development, birth traits, and growth performance in postnatal Korean native calves

“…Meanwhile, three controls (internal standards) were prepared in new 1. Longissimus dorsi muscle sampling and total RNA extraction Longissimus dorsi muscle sampling and total RNA extraction were performed with minor modifications of previously described methods [10,11]. Tissue samples (approximately 2 g) were collected from the longissimus dorsi muscles of 31-dayold calves (n = 8) by biopsy.…”

“…Real-time PCR was performed with minor modifications of previously described methods described [10,11].…”

Effects of Different Protein Levels on Growth Performance and Stress Parameters in Beef Calves Under Heat Stress

“…Following that, the temperature and RH in the chambers were raised to each THI level for 21 days (HS). Four THI treatments were categorized as threshold (22 to 24°C, 60% RH: THI = 70 to 73), mild (26 to 28°C, 60% RH: THI = 74 to 76), moderate (29 to 31°C, 80% RH: THI = 81 to 83), and severe (32 to 34°C, 80% RH: THI = 89 to 91) stress levels 15 . The study included four different THI groups and was designed to consist of four levels of dry bulb temperature (22 to 24°C, 26 to 28°C, 29 to 31°C, 32 to 34°C) and two levels of RH (60 and 80%).…”