Functional and metabolic changes in rabbits undergoing continuous heat stress for 24 days

1995 ◽  
Vol 61 (2) ◽  
pp. 399-405 ◽  
Author(s):  
A. Amici ◽  
A. Finzi ◽  
P. Mastroiacono ◽  
M. Nardini ◽  
G. Tomassi

AbstractIntensively reared rabbits are particularly sensitive to heat stress. For this reason it is useful to identify reliable stress indicators to evaluate peculiar stress conditions of the breeding environment.In order to recognize which changes in biochemical and functional measurements can be utilized as stress indicators, three groups of eight New Zealand White rabbits, of 2·8 kg body weight and 11 weeks of age, were kept in individual cages and submitted to different environmental conditions.Group 1 was located in a climatic chamber at 33·5 (s.e. 0·5)°C and relative humidity 0·62 (s.d. 0·05) and groups 2 and 3 (control) at 18·0 (s.d. 0·5)°C. Group 1 was given ad libitum a commercially pelleted diet, group 2 was pairfed with group 1, and group 3 was given food ad libitum. For all the groups, at days 0, 1, 6, 12 and 24, the following measurements were made: body weight, rectal temperature, food consumption and plasma glucose, cholesterol, urea, triglycerides, uric acid, and glutamate oxalacetate transaminase, glutamate pyruvate transaminase, thiobarbituric acid-reactive substances, vitamin A and vitamin E, SH-groups and total (peroxil) radical-trapping antioxidant parameter (TRAP).Food consumption of animals exposed to 33·5 °C was strongly reduced in the 1st day (13·6 v. 161·6 glday); a gradual increase until the end of the trial was then observed (98·8 v. 177·3 gl day). Rectal temperature rapidly increased and remained stable and higher than in the control groups all through the trial (P < 0·01). The major changes in the measurements of the heat stressed animals were a significant increase of the plasma level of vitamin E at days 6, 12, 24 (P < 0·05), and a significant reduction of the plasma concentration of SH-groups and TRAP (P < 0·05).The results suggest an impairment or overload of antioxidant systems after thermal stress, indicating a reduced resistance to biological and environmental stress factors. The results also indicate that some parameters of antioxidant systems can be used to select a significant stress indicator.

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 117-117
Author(s):  
Edith J Mayorga ◽  
Erin A Horst ◽  
Brady M Goetz ◽  
Sonia Rodríguez-Jiménez ◽  
Megan A Abeyta ◽  
...  

Abstract Objectives were to determine the effects of rapamycin on biomarkers of metabolism and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n=32; 63.5±0.8 BW) where blocked by BW and randomly assigned to 1 of 4 therapeutic-environmental treatments: 1) thermoneutral (TN) control (n=8; TNCtl), 2) TN and rapamycin (n=8; TNRapa), 3) HS control (n=8; HSCtl), or 4) HS and rapamycin (n=8; HSRapa). The trial consisted of 2 experimental periods (P). During P1 (10d), pigs were fed ad libitum and housed in TN conditions (21.3±0.01°C). During P2 (24h), HSCtl and HSRapa pigs were exposed to constant HS (35.5±0.1°C); while TNCtl and TNRapa remained in TN conditions. Rapamycin (0.15 mg/kg BW) was orally administered twice daily (0700 and 1800 h) during P1 and P2. HS increased rectal temperature, skin temperature, and respiration rate compared to TN counterparts (1.28°C, 8.68°C, and 87 bpm, respectively; P&lt; 0.01). Feed intake (FI) markedly decreased in HS relative to TN treatments (64%; P&lt; 0.01). Additionally, pigs exposed to HS lost BW (4 kg; P&lt; 0.01), while TN pigs gained BW (0.7 kg; P&lt; 0.01). Overall, circulating white blood cells decreased in HS compared to TN pigs (19%; P=0.01). Circulating neutrophils did not differ across treatments; however, lymphocytes, monocytes, and basophils decreased in HS relative to TN pigs (23, 33, and 38%, respectively; P≤0.07). Despite marked changes in phenotypic parameters, circulating glucose and blood urea nitrogen did not differ among treatments (P &gt;0.10). However, insulin:FI increased in HS relative to TN treatments (P=0.04). Plasma non-esterified fatty acids (NEFA) increased in HS relative to TN treatments; although this difference was driven by increased NEFA in HSCtl compared to TN and HSRapa pigs (P&lt; 0.01). In summary, pigs exposed to HS had altered phenotypic, metabolic, and leukocyte responses; however, rapamycin administration had little to no effect on any of the variables measured.


1963 ◽  
Vol 41 (12) ◽  
pp. 2463-2471 ◽  
Author(s):  
M. J. Veen ◽  
G. Russell ◽  
G. H. Beaton

Rectal temperature in male rats fell slowly and gradually from ad libitum and pair-led control levels throughout a thiamine depletion period. During this period, food consumption dropped suddenly and sharply to a minimal level. A single oral dose of 50 μg of thiamine hydrochloride produced, within 4 hours, a significant rise (to less than control levels) in rectal temperature and an increase in food consumption within 24 hours. The increase in temperature was independent of the ingestion of food since diet was withheld during the 4 hours following thiamine administration. Subsequent feeding of control diet (containing thiamine) had not further increased the "4-hour" temperature after 24 hours. With continued feeding of control diet, rectal temperature rose to control levels after 3 days. On subsequent withdrawal of dietary thiamine from the deficient group, temperature and food consumption fell as before. When the animals were again repleted with 50 μg thiamine and deficient diet was continued, temperatures rose to the same level reached after the first thiamine administration. A third deprivation and repletion produced identical results.Food restriction alone, in pair-fed control groups, induced an initial elevation of rectal temperature above ad libitum control levels as temperatures in the deficient group were falling, and an eventual decrease below ad libitum control levels only after prolonged food restriction. It is suggested that the initial fall in body temperature in thiamine-deficient rats is not simply a terminal result of food restriction per se, but may reflect alterations in metabolism due to the deficiency.


1971 ◽  
Vol 13 (1) ◽  
pp. 51-57 ◽  
Author(s):  
S. R. Morrison ◽  
L. E. Mount

SUMMARYPigs fed ad libitum were exposed to changes from 22 to 33°C and from 33 to 20°C. Responses were investigated in two groups of animals kept for three successive periods of four weeks at 22°, 33° and finally 20°C.Twenty-four hr after the first change, from 22 to 33°C, there was a decline in body weight; after the second change, from 33 to 20°C, there was a large increase. After the change to 33°C, feed intake by the second day and growth rate for the first week were about the same as at the end of the four weeks, but about 12 days were required for water intake, rectal temperature and respiratory rate to reach steady values.After the change from 33 to 20°C, steady values for respiratory rate and rectal temperature were reached in one and 12 days respectively. The rate of gain in weight increased to reach a peak nine days following the temperature change and then declined.


Author(s):  
Razali Daud

The aim of this study was to determine the protective effect of vitamin E on mice heart. Twentyfivemalemiceweighing±40gattheageof3monthswereused.Themicewereadaptedforaweekandfedbasaldiet.Themicewerefednormaldietascontrol(group1),highfat+50IUVitaminE(groupII);highfat + 100 IU Vitamin E (group III) high fat + 200 IU Vitamin E (group IV); high fat + 400 IUVitamin E (Group V). Diet was given about 10% body weight, water was given ad libitum every day. After 3 months, all animal were then killed. The hearts were collected for routine histopathologicalexamination. The result indicate that lesions in the heart consist of swollen eosinophilic hyalinization ofcytoplasm, vacuolization, and necrosis myocardium (cardiomiopathy) in all mice receiving high fat dietwith less than 400 IU Vitamin E.Keywords: high fat diet, vitamin E, cardiovascular diseases 


1993 ◽  
Vol 3 (2) ◽  
pp. 177-193 ◽  
Author(s):  
G. Patrick Lambert ◽  
Timothy L. Bleiler ◽  
Ray-Tai Chang ◽  
Alan K. Johnson ◽  
Carl V. Gisolfi

Eight male runners performed four 2-hr treadmill runs at 65% ~ 0 , m a x in the heat (35"C, 15-20% RH). A different beverage was offered each trial and subjects drank ad libitum for 2 min every 20 min. The beverages were, 6% carbohydrate (CHO) solution (NC 6), 6% carbonated-CHO solution (C 6), 10% CHO solution (NC 10), and 10% carbonated-CHO solution (C 10). NC 6 and C 6 contained 4% sucrose and 2% glucose. NC 10 and C 10 contained high fructose corn syrup. Subjects drank more NC 6 than C 6. Fluid consumption was not different among other trials. During all trials, volume consumed and %ΔPV declined while heart rate and rectal temperature increased (p<0.05). No significant differences occurred between beverages for these variables. Percent body weight lost was greater (p<0.05) for the C 10 trial compared to the NC 6 trial. Neither sweat rate, percent fluid replaced, plasma [Na+], [K+], osmolality, percent of drink volume emptied from the stomach, or glucose concentration differed among trials. Plasma [K+] and osmolality increased (p<0.05) over time. Ratings of fullness and thirst were not different among beverages, although both perceptions increased (p<0.05) with time. It is concluded that (a) carbonation decreased the consumption of the 6% CHO beverage; (b) fluid homeostasis and thermoregulation were unaffected by the solutions ingested; and (c) fluid consumption decreased with time, while ratings of fullness and thirst increased.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Warunyoo Phannasorn ◽  
Arpamas Chariyakornkul ◽  
Phumon Sookwong ◽  
Rawiwan Wongpoomchai

Rice bran oil (RBO) comprises various nutrients and phytochemicals which exhibit several health benefits. There are no studies regarding the functional effects of different colours of RBO. This study was aimed to compare the constituents and antioxidant activities of white rice bran oil (WRBO) and coloured rice bran oil (CRBO). Each RBO showed similar free fatty acid profiles. However, greater amounts of vitamin E, phytosterols, carotenoids, and chlorophylls were found in CRBO, which had lower γ-oryzanol content than WRBO. Oxidative stress was induced in male mice by an overdose of acetaminophen (APAP) at 300 mg/kg body weight. The mice were then fed with RBO at the equivalent dose to 100 mg/kg body weight of γ-oryzanol three hours later and sacrificed six hours after APAP treatment. The administration of 100 mg γ-oryzanol equivalent in CRBO ameliorated APAP-induced hepatotoxicity in mice more strongly than 100 mg γ-oryzanol equivalent in WRBO, as evidenced by the significant reduction of serum ALT, hepatocellular necrosis, and hepatic lipid peroxidation. CRBO could improve xenobiotic-metabolizing and antioxidant enzyme activities, including glutathione S -transferase, superoxide dismutase, glutathione peroxidase, and glutathione reductase, and also increase mRNA expression of various antioxidant-responsive genes. Vitamin E, phytosterols, carotenoids, and chlorophyll might be the protective compounds in CRBO that alleviate APAP-induced hepatotoxicity through the interruption of APAP metabolism and the activation of antioxidant systems at both transcriptional and enzymatic levels. These findings might provide a protective role of CRBO on oxidative stress associated with several degenerative diseases.


2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 118-118
Author(s):  
Edith J Mayorga ◽  
Erin A Horst ◽  
Brady M Goetz ◽  
Sonia Rodríguez-Jiménez ◽  
Megan A Abeyta ◽  
...  

Abstract Objectives were to determine the effects of mitoquinol (MitoQ) on performance, metabolism, and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n=32; 59±1 kg BW) where blocked by BW and randomly assigned to 1 of 4 therapeutic-environmental treatments: 1) thermoneutral (TN) control (n=8; TNCtl), 2) TN and MitoQ (n=8; TNMitoQ), 3) HS control (n=8; HSCtl), or 4) HS and MitoQ (n=8; HSMitoQ). The trial consisted of two experimental periods (P). During P1 (2d), pigs were fed ad libitum and housed in TN conditions (20.6±0.1°C). During P2 (24h), HSCtl and HSMitoQ pigs were exposed to continuous HS (35.2±0.03°C); while TNCtl and TNMitoQ remained in TN conditions. Mitoquinol was orally administered twice daily (0700 and 1800 h; 40 mg/d) during P1 and P2. Pigs exposed to HS had increased rectal temperature, skin temperature, and respiration rate (1.46°C, 6.79°C, and 101 bpm, respectively; P&lt; 0.01) compared to their TN counterparts. Acute HS markedly decreased feed intake (67%; P&lt; 0.01). Additionally, HS pigs lost BW compared to their TN counterparts (-4.7 vs. +1.6 kg, respectively; P&lt; 0.01); however, the reduction in BW was less severe in HSMitoQ compared to HSCtl pigs (-3.85 vs. -5.50 kg, respectively; P&lt; 0.01). Circulating glucose increased in HSMitoQ relative to HSCtl pigs (15%; P=0.04). Non-esterified fatty acid (NEFA) concentrations were increased in HS compared to TN pigs (P&lt; 0.01), although this difference was influenced by increased NEFA in HSCtl relative to HSMitoQ pigs (251 vs. 142 μEq/L; P&lt; 0.01). Insulin:feed intake tended to increase in HS relative to TN pigs (P=0.09). Overall, no differences in blood urea nitrogen or cell blood counts were observed across treatments (P &gt;0.10). In conclusion, acute HS exposure negatively altered animal performance and metabolism; however, administering MitoQ appeared to ameliorate the HS response.


Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1286
Author(s):  
Surinder S. Chauhan ◽  
Frank R. Dunshea ◽  
Tim E. Plozza ◽  
David L. Hopkins ◽  
Eric N. Ponnampalam

The impact of antioxidant supplementation and short-term heat stress on lamb body weight gain, meat nutritional profile and functionality (storage stability of lipids and colour) of lamb meat was investigated. A total of 48 crossbred ((Merino × Border Leicester) × Dorset) lambs (42 ± 2 kg body weight, 7 mo age) were randomly allocated to three dietary treatments (n = 16) by liveweight (LW) that differed in dosage of vitamin E and selenium (Se) in the diet. Vitamin E and Se levels in the control (CON), moderate (MOD) and supranutritional (SUP) dietary treatments were 28, 130 and 228 mg/kg DM as α-tocopherol acetate and 0.16, 0.66 and 1.16 mg Se as SelPlex™/kg DM, respectively. After four weeks of feeding in individual pens, including one week of adaptation, lambs were exposed to two heat treatments. Animals were moved to metabolism cages for one week and subjected to heat treatments: thermoneutral (TN; 18–21 °C and 40–50% relative humidity) and heat stress (HS; 28–40 °C and 30–40% relative humidity) conditions, respectively. Final LW and hot carcass weight were influenced by dietary treatments with higher final live weight (FLW) (p = 0.05; 46.8 vs. 44.4 and 43.8 kg, respectively) and hot carcass weight (HCW) (p = 0.01; 22.5 vs. 21.3 and 21.0 kg, respectively) recorded in lambs fed the SUP as opposed to the CON and MOD diets. Vitamin E concentration in the longissimus lumborum (LL) muscle tended to be higher in lambs fed MOD or SUP diets than the CON group. Lipid oxidation of aged meat at 72 h of simulated retail display was reduced by antioxidant supplementation. Short-term (one week) heat stress treatment significantly increased muscle linoleic acid and total omega-6 concentrations compared with the CON group. The results demonstrate that four-week antioxidant supplementation at the SUP level improved animal productivity by increasing LW and carcass weight and the functionality of meat exhibited by reduced lipid oxidation. An increase in muscle omega-6 fatty acid concentration from short-term heat stress may induce oxidative stress via proinflammatory action.


1999 ◽  
Vol 24 (4) ◽  
pp. 349-361 ◽  
Author(s):  
Tom M. Mclellan ◽  
Stephen S. Cheung ◽  
William A. Latzka ◽  
Mike N. Sawka ◽  
Kent B. Pandolf ◽  
...  

The present study examined the effects of dehydration from prior exercise on subsequent exercise tolerance time (TT) that involved wearing nuclear, biological, and chemical (NBC) protective clothing. It was hypothesised that TT would be reduced in the dehydrated state. Ten men undertook continuous treadmill walking at 4.8 km • h−1 at 35 °C and 50% relative humidity, wearing NBC clothing while euhydrated (EU) or dehydrated (D) by 2.3% of body weight. Hydration status had no impact on thermoregulatory or cardiovascular responses during exercise. Also rectal temperature at exhaustion did not differ between EU (38.52 ± 0.39 °C) and D (38.43 ± 0.45 °C). Exercise TT during this uncompensable heat stress was reduced significantly for D (47.7 ± 15.3 min) compared with EU (59.0 ± 13.6 min). It was concluded that prior exercise leading to levels of dehydration to 2.3% of body weight, together with subsequent fluid restriction during exposure to uncompensable heat stress, impaired TT while wearing the NBC protective clothing. The integration of these findings together with other comparable studies that have examined the influence of hypo- and hyperhydration on TT while wearing NBC protective clothing revealed that hydration status has less effect on TT as the severity of uncompensable heat stress increases. Key words: thermoregulation, protective clothing, heat tolerance, rectal temperature


1963 ◽  
Vol 41 (1) ◽  
pp. 2463-2471
Author(s):  
M. J. Veen ◽  
G. Russell ◽  
G. H. Beaton

Rectal temperature in male rats fell slowly and gradually from ad libitum and pair-led control levels throughout a thiamine depletion period. During this period, food consumption dropped suddenly and sharply to a minimal level. A single oral dose of 50 μg of thiamine hydrochloride produced, within 4 hours, a significant rise (to less than control levels) in rectal temperature and an increase in food consumption within 24 hours. The increase in temperature was independent of the ingestion of food since diet was withheld during the 4 hours following thiamine administration. Subsequent feeding of control diet (containing thiamine) had not further increased the "4-hour" temperature after 24 hours. With continued feeding of control diet, rectal temperature rose to control levels after 3 days. On subsequent withdrawal of dietary thiamine from the deficient group, temperature and food consumption fell as before. When the animals were again repleted with 50 μg thiamine and deficient diet was continued, temperatures rose to the same level reached after the first thiamine administration. A third deprivation and repletion produced identical results.Food restriction alone, in pair-fed control groups, induced an initial elevation of rectal temperature above ad libitum control levels as temperatures in the deficient group were falling, and an eventual decrease below ad libitum control levels only after prolonged food restriction. It is suggested that the initial fall in body temperature in thiamine-deficient rats is not simply a terminal result of food restriction per se, but may reflect alterations in metabolism due to the deficiency.


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