Effects of heat stress on Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activities of broiler chickens vital organs

Alleviating effect of methionine on intestinal mucosal injury induced by heat stress

Climate change is an increasing concern of stakeholders worldwide. The intestine is severely impacted by the heat stress. This study aimed to investigate the alleviating effects of methionine on the intestinal damage induced by heat stress in mice. The mice were divided into four groups: control group (C), methionine deficiency group (MD), methionine + heat stress group (MH), and methionine deficiency + heat stress group (MDH). Histopathological techniques, PAS-Alcian blue staining, immunohistochemistry method, biochemical quantification method, ELISA, and micro method were used to study the changes in the intestinal mucosal morphology, the number of goblet cells, the expression of tight junction proteins, the peroxide product contents and antioxidant enzyme activities, the intestinal mucosal damage, the content of immunoglobulins and HSP70, the activity of Na+/K+-ATPase. The results showed that methionine can improve intestinal mucosal morphology (increase the villi height, V/C value, and muscle layer thickness, decrease crypt depth), increase the expression of tight junction proteins (Claudin-1, Occludin, ZO-1) and the content of DAO, decrease the content of intestinal mucosa damage markers (ET, FABP2) and peroxidation products (MDA), increase the activity of antioxidant enzymes (GR, GSH-Px, SOD), the number of goblet cells, the contents of immunoglobulins (sIgA, IgA, IgG, IgM) and stress protein (HSP70), and the activity of Na+/K+-ATPase. It is suggested that methionine can alleviate intestinal damage in heat-stressed mice.

Navel orange peel hydroethanolic extract as a phytogenic feed supplement: impacts on growth, feed intake, nutrient digestibility, and serum metabolites of heat stressed growing rabbits

Currently, using agricultural wastes in animal production has gained worldwide interest. Hence, herein, an eight-week trial was performed to explore the effects of supplemental navel orange peel extract (NPE) on the growth, feed utilization, nutrient digestibility, antioxidant, and hematological parameters of heat-stressed rabbits. In total, 75 weaned rabbits were randomly assigned into five groups. The first group was reared in the winter (mild weather) and fed an untreated pelleted diet (W-NPE-0; control). The other four groups were reared in the summer (hot climate) and fed the control diet fortified with 0 (S-NPE-0), 250 (S-NPE-250), 500 (S-NPE-500), or 1000 (S-NPE-1000) mg NPE/kg diet. The results indicated that thermal-stressed rabbits (S-NPE-0) had significantly lower feed intake, growth performance, hematological indices, serum lipid profile, and antioxidative status, but higher lipid peroxidation compared to the W-NPE-0 group. However, the highest final weight and feed intake were recorded in the S-NPE-1000 group compared with the S-NPE-0 group. Also, supplemental NPE in the growing rabbit diet, especially the S-NPE-1000 group, enhanced the hematological and antioxidative indicators. In conclusion, NPE supplementation in growing rabbit diets could be used to efficiently mitigate the detrimental effects of chronic temperature stress on performance, hematobiochemical features, and oxidative stability.

Effects of Chronic Thermal Stress on Performance, Energy Metabolism, Antioxidant Activity, Brain Serotonin, and Blood Biochemical Indices of Broiler Chickens

Simple Summary

In the tropical and subtropical regions, heat stress is the main limiting factor of poultry industries. In this context, broilers are more liable to thermal stress due to their fast growth, rapid metabolic rate, and high level of production. The aim of the current work was to analyze changes in the brain serotonin, energy metabolism, antioxidant biomarkers, and blood chemistry of broiler chickens subjected to chronic thermal stress. Thermal stress disturbed the antioxidant defense system and energy metabolism and exhausted ATP levels in the liver tissues of broiler chickens. Interestingly, chronic thermal stress reduced the level of brain serotonin and the activity of CoQ10 in liver tissues.

Abstract

The aim of this paper was to investigate the effects of chronic thermal stress on the performance, energy metabolism, liver CoQ10, brain serotonin, and blood parameters of broiler chickens. In total, 100 one-day-old chicks were divided into two equal groups of five replicates. At 22 days of age and thereafter, the first group (TN) was maintained at a thermoneutral condition (23 ± 1 °C), while the second group (TS) was subjected to 8 h of thermal stress (34 °C). The heat-stressed group showed significantly lower ADFI but higher FCR than the thermoneutral group (p = 0.030 and 0.041, respectively). The TS group showed significantly higher serum cholesterol, ALT, and AST (p = 0.033, 0.024, and 0.010, respectively). Meanwhile, the TS group showed lower serum total proteins, albumin, globulin, and Na+ than the TN group (p = 0.001, 0.025, 0.032, and 0.002, respectively). Furthermore, the TS group showed significantly lower SOD and catalase in heart tissues (p = 0.005 and 0.001, respectively). The TS group showed significantly lower liver ATP than the TN group (p = 0.005). Meanwhile, chronic thermal stress significantly increased the levels of ADP and AMP in the liver tissues of broiler chickens (p = 0.004 and 0.029, respectively). The TS group showed significantly lower brain serotonin (p = 0.004) and liver CoQ10 (p = 0.001) than the TN group. It could be concluded that thermal stress disturbed the antioxidant defense system and energy metabolism and exhausted ATP levels in the liver tissues of broiler chickens. Interestingly, chronic thermal stress reduced the level of brain serotonin and the activity of CoQ10 in liver tissues.

Effect of glutamine on the growth performance, digestive enzyme activity, absorption function, and mRNA expression of intestinal transporters in heat-stressed chickens

To explore the effect of glutamine (Gln) on the growth performance, digestive enzyme activity, absorption function and mRNA expression of intestinal transporters in heat-stressed chickens, 540 21-day-old Arbor Acres broilers were randomly assigned to a control group (no stress, NS), Gln group (Chickens were administered 0.5% and 1.0% Gln, respectively), heat stress group (HT), and Gln + HT group (Chickens were administered 0.5% and 1.0% Gln, respectively). The chickens in the HT and Gln + HT groups were reared under HT (36 ± 1 °C for 10 h/d and 22 ± 1 °C for 14 h/d), for 21 days. In contrast to the NS group, heat stress caused a reduction in the body weight gain (BWG); feed intake (FI); activity of trypsin, lipase, alkaline phosphatases, Ca²⁺ and Mg²⁺ adenosine triphosphatases, and Na⁺-K⁺-ATPase; and content of glutathione and d-xylose (P < 0.05) in the other groups. In addition, compared to the F:G and expression levels in the NS group, the heat stress increased the feed intake:body weight gain (F:G) and mRNA expression levels of SGLT1, CaBP-D28k, and L-GSBP (P < 0.05). Furthermore, HT-challenged birds were pretreated with Gln, the BWG; FI; activity of trypsin, lipase, alkaline phosphatase, Ca²⁺ and Mg²⁺ adenosine triphosphatases, and Na⁺-K⁺-ATPase; and content of glutathione and d-xylose (P < 0.05) were dramatically increased, but it decreased the F:G and mRNA expression levels of SGLT1, CaBP-D28k, and L-GSBP (P < 0.05) in the HT group. In summary, Gln can effectively improve growth performance and may promote digestion and absorption in the gastrointestinal tract by mediating the mRNA expression level of nutrient transporters and Gln metabolism in heat-stressed broilers.

Pathophysiology of avian intestinal ion transport

The gut has great importance for the commercial success of poultry production. Numerous ion transporters, exchangers, and channels are present on both the apical and the basolateral membrane of intestinal epithelial cells, and their differential expression along the crypt-villus axis within the various intestinal segments ensures efficient intestinal absorption and effective barrier function. Recent studies have shown that intensive production systems, microbial exposure, and nutritional management significantly affect intestinal physiology and intestinal ion transport. Dysregulation of normal intestinal ion transport is manifested as diarrhoea, malabsorption, and intestinal inflammation resulting into poor production efficiency. This review discusses the basic mechanisms involved in avian intestinal ion transport and the impact of development during growth, nutritional and environmental alterations, and intestinal microbial infections on it. The effect of intestinal microbial infections on avian intestinal ion transport depends on factors such as host immunity, pathogen virulence, and the mucosal organisation of the particular intestinal segment.

Transport stress induces weight loss and heart injury in chicks: disruption of ionic homeostasis via modulating ion transporting ATPases

Transportation is inevitable in the poultry industry, and it can induce stress to chicks in varying degrees, such as mild discomfort, sometimes even death. However, the research about the effects of transport stress on the weight loss and heart injury of chicks is lacking. To elucidate the underlying mechanism of transport stress-induced effects, chicks were transported for 2h, 4h and 8h. The creatinine kinase (CK) activities, the ionic contents, the ATPases activities and the transcription of the ATPase associated subunits in chick heart were detected. The results showed that transport stress increased the weight loss and the CK activity, disturbed the ionic (K⁺, Ca²⁺, Mg²⁺) homeostasis and inhibited the ATPase (Na⁺-K⁺-ATPase, Ca²⁺-ATPase, Mg²⁺-ATPase and Ca²⁺-Mg²⁺-ATPase) activities, increased the ATP content and downregulated the gene expression levels of the ATPase associated subunits in heart. In conclusion, transport stress disturbed the ionic homeostasis via modulating ion transporting ATPases and the transcriptions of the associated subunits, and ultimately induced weight loss and heart injury in chicks.

The effect of dietary phosphorus on heat shock protein mRNAs during acute heat stress in male broiler chickens (Gallus gallus)

A 2 x 2 factorially arranged completely randomized experimental design was used to study the relationship between inorganic phosphorus (Pi) and heat shock protein (HSP) mRNA expression in different organs of commercial broiler cockerels during acute heat stress (HS). Brain, heart, liver and spleen were assayed for hsp70, hsp90alpha and hsp90beta mRNA. At 1 day of age, chickens were assigned randomly to two dietary Pi treatment groups (Pi-: 0.16%; Pi+: 0.5%). At 3 weeks of age, half of the chickens in each Pi group were subjected to HS (Ta=41 degrees C, 60 min) while the other half was maintained in a thermoneutral environment (CN, Ta=25 degrees C). The results showed inter-organ variation in the expression of HSP mRNAs. Brain expressed the most HSP mRNAs while spleen expressed the least. When broilers were subjected to HS, the expression of HSP mRNAs was influenced positively by the consumption of the Pi+ diet. However, analysis of variance revealed that Ta influenced HSP transcription more than phosphorus availability. Thermal stress caused induction of hsp90alpha and hsp90beta in heart, liver and spleen, but hsp90alpha and hsp9beta mRNA levels were stable in brain. Transcription of hsp70 increased (P< or =0.05) in all organs from chickens in HS groups when compared to chickens in CN groups. Although Pi+ did not show any significant increases in the expression of hsp mRNAs, there were consistently larger HSP mRNA values in liver and spleen tissues. The high expression of hsp90alpha and hsp90beta in brain of chicks in both CN and HS conditions could be due to the involvement of hsp90 in steroid hormone receptors or the high metabolic activity of neurons in the central nervous system.

The effect of thermal preslaughter stress on the susceptibility of broiler chickens differing with respect to growth rate, age at slaughter, blood parameters, and ascites mortality, to hemorrhages in muscles

In this study we investigated the occurrence of hemorrhages in four groups of electrically stunned broilers, differing with respect to growth rate, age at slaughter, hemodynamic parameters, and ascites mortality. In addition, the effect of three thermal preslaughter conditions on hemorrhage occurrence in thigh and breast muscles was studied. Broilers were either reared at a thermoneutral or low temperature regimen, and were either restricted in their feed consumption or consumed feed ad libitum. Prior to slaughter the broilers were exposed for 2 +/- 0.5 h to either cold (4 +/- 2 C, RH 100%), moderate (19 +/- 2 C, RH: 70 to 80%), or warm (30 +/- 2 C, RH: 60 to 70%) conditions. There was no effect of rearing group, nor was there an interaction between rearing group and preslaughter condition on hemorrhage scores in the thighs or breasts. Preslaughter conditions only affected hemorrhage scores in the left thigh. Scores were highest in broilers exposed to moderate preslaughter conditions. These data indicate that the cause of hemorrhages in muscles is multifactorial. Hemorrhage severity was not diminished in broilers retarded in growth. Pathological hemodynamic adaptations to low rearing temperatures, leading to ascites, did not increase hemorrhage severity, neither upon exposure to moderate nor to cold or warm preslaughter conditions.

Effects of ambient temperature on broiler mineral balance partitioned into urinary and faecal loss

1. Two experiments were conducted on control (intact) and colostomised 4 to 7 week old broilers to evaluate the influence of 24 degrees C, diurnally cycling 24 to 35 degrees C and chronic 35 degrees C ambient temperatures on broiler mineral balance, urinary and faecal mineral excretion and urinary osmolar characteristics. 2. In the first experiment, colostomy had no significant effect on mineral balance. However, broilers exposed to high cycling ambient temperature reduced their retention of phosphorus, potassium, sodium, magnesium, sulphur, manganese, copper and zinc compared with birds housed at 24 degrees C. 3. Despite the minimal effect of high ambient temperature on urine production, minerals excreted disproportionately excreted in urine included potassium, magnesium, phosphorus and sulphur while copper and magnesium were lost primarily via the faeces. 4. In the second experiment, exposure to 35 degrees C increased urine output from 50.7 ml/12 h per kg of body weight at 24 degrees C to 101.3 ml/12 h per kg of body weight and was associated with an increased urine:water ratio and reduced urine osmolality. 5. Reduced urinary chloride and higher potassium, phosphorus, sulphur, sodium, magnesium, calcium and manganese excretion was observed for broilers housed in under high ambient temperatures compared to 24 degrees C. 6. These studies suggest that high ambient temperatures adversely influence mineral metabolism and, furthermore, that the route of excretion varies with the specific mineral and the environmental temperature exposure.