scholarly journals Effect of High Ambient Temperature in Early and Late Lactation on Litter Growth and Survival in Rats

1973 ◽  
Vol 26 (5) ◽  
pp. 1171 ◽  
Author(s):  
Helen Hearnshaw ◽  
Manika Wodzicka-Tomaszewska
Keyword(s):  
Growth Rate ◽  
Heat Stress ◽  
Ambient Temperature ◽  
High Ambient Temperature ◽  
Litter Production ◽  
Growth And Survival

The effect of heat stress, applied either during the first half or during the second half of lactation, on total litter production per rat was studied. The survival of the pups, the growth rate of the surviving pups, the liveweight changes, and feed intakes of the rats were also measured. Some observations were also made on maternal and pup behaviour.

scholarly journals The effects of acute heat stress on proliferative and apoptotic processes in the rat adrenal cortex

2013 ◽  
Vol 65 (3) ◽  
pp. 905-909 ◽  
Author(s):  
Dragana Petrovic-Kosanovic ◽  
V. Ajdzanovic ◽  
Maja Cakic-Milosevic ◽  
Vesna Koko ◽  
Verica Milosevic
Keyword(s):  
Heat Stress ◽  
Ambient Temperature ◽  
Adrenal Cortex ◽  
Light And Electron Microscopy ◽  
Relative Number ◽  
Zona Glomerulosa ◽  
High Ambient Temperature ◽  
Zona Fasciculata ◽  
Mitotic Chromosomes ◽  
Ki 67

Hyperthermia can cause significant structural and functional reorganization of tissues and organs. The proliferative and apoptotic processes of rat adrenal cortex were analyzed by light and electron microscopy after an acute exposure to high ambient temperature. Animals were divided in two groups. The first group consisted of intact controls. The rats from the second group were exposed to a high ambient temperature of 38?C for 60 min. Mitotic chromosomes and the largest number of immunoreactive nuclei for the Ki-67 were observed in the zona reticularis (ZR) of the control animals. The relative number of mitoses after heat stress showed a significant decrease in the zona glomerulosa (ZG; 66.8%), zona fasciculata (ZF; 27.8%) and ZR (86.7%) (for all zones p<0.05), while in the whole adrenal cortex the after-treatment decrease was 61.9% (p<0.05) compared to the controls. Under heat stress numerous apoptotic nuclei were seen at the light and ultrastructural levels in all the zones of the adrenal cortex. Such dynamics of mitosis/apoptosis events seriously affect adrenal cortex morphology.

Genetic selection for growth performance and thermal tolerance under high ambient temperature after two generations using heat shock protein 90 expression as an index

2019 ◽  
Vol 59 (4) ◽  
pp. 628 ◽  
Author(s):  
Lamiaa M. Radwan ◽  
Mahmoud. Y. Mahrous
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Ambient Temperature ◽  
Rhode Island ◽  
Genetic Selection ◽  
Heat Shock Protein 90 ◽  
High Ambient Temperature ◽  
Two Generations ◽  
Selection For

Genetic selection for productive performance in high ambient temperatures was performed on two chicken strains, Rhode Island Red and Sinai, for two generations, and the heritable responses to tolerance were estimated using heat shock protein 90 (HSP90) gene expression. The results are summarised as follows: (1) heat stress negatively affected some economic traits, mainly bodyweight. This effect was more pronounced in the parent stock than in the first generation (F1) and second generation (F2). (2) This effect was modulated by the chicken strain, and the decreased bodyweight was more pronounced in RI strain than in the Sinai strain, indicating that the Sinai strain is more tolerant to high ambient temperature. (3) The offspring (F1 and F2) of both strains were more tolerant to high ambient temperature; this trend was also true for the parents of these two strains. (4) HSP90 mRNA expression was the same in both strains under normal conditions in all three generations. (5) Under high ambient temperature conditions, the Sinai strain (all generations) showed significantly increased HSP90 mRNA expression compared with the Rhode Island Red strain. These findings suggest that heat tolerance is passed from parents to offspring. We recommended that selection for heat-stress tolerance be applied to producing commercial strains reared in hot climate conditions.

scholarly journals 216 Thermoregulatory and physiological responses of sows at different reproductive stages exposed to increasing ambient temperature

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 7-7
Author(s):  
Betty R McConn ◽  
Alan W Duttlinger ◽  
Kouassi R Kpodo ◽  
Jacob M Maskal ◽  
Brianna N Gaskill ◽  
...  
Keyword(s):  
Heat Stress ◽  
Ambient Temperature ◽  
Physiological Responses ◽  
Blood Gases ◽  
Respiratory Alkalosis ◽  
Stress Sensitivity ◽  
Late Gestation ◽  
Acid Base Balance ◽  
Study Objective ◽  
Cell Counts

Abstract Pregnant sows, especially during late-gestation, may be susceptible to heat stress due to increased metabolic heat production and body mass. Therefore, the study objective was to determine the thermoregulatory and physiological responses of sows exposed to increasing ambient temperature (TA) at 3 reproductive stages. In 3 repetitions, 27 multiparous sows (parity 3.22±0.89) were individually housed and had jugular catheters placed 5.0±1.0 d prior to the experiment. To differentiate between reproductive stages, sows were categorized as open (not pregnant, n=9), mid-gestation (59.7±9.6 days pregnant, n=9), or late-gestation (99.0±4.8 days pregnant, n=9). During the experiment, sows were exposed to 6 consecutive 1 h periods of increasing TA (period 1, 14.39±2.14°C; period 2, 16.20±1.39°C; period 3, 22.09±1.87°C; period 4, 26.34±1.39°C; period 5, 30.56±0.81°C; period 6, 35.07±0.96°C), with 1 h transition phases in between each period. Respiration rate (RR), heart rate (HR), skin temperature, and vaginal temperature (TV) were measured every 20 min and the mean was calculated for each period. At the end of each period, blood gases, leukocytes, and red blood cell counts were measured. Overall, RR and HR were greater (P≤0.04; 45.6% and 12.9%, respectively) in late-gestation versus mid-gestation sows. Compared to mid-gestation and open sows, TV tended to be greater (P=0.06) during period 4 (0.18°C and 0.29°C, respectively) and period 5 (0.14°C and 0.18°C, respectively) in late-gestation sows. Blood O2 increased (P&lt; 0.01; 18.1%) for all sows with advancing period, regardless of reproductive stage. Late-gestation sows had reduced (P=0.02; 16.1%) blood CO2 compared to mid-gestation sows, regardless of period. In summary, late-gestation sows appear to be more sensitive to increasing TA as indicated by increased RR, HR, TV, and blood O2, and reduced blood CO2 when compared to mid-gestation or open sows. This change in O2 and CO2, due to increasing RR and heat stress sensitivity of late-gestation sows, may suggest an alteration to the acid-base balance, leading to respiratory alkalosis.

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