Resveratrol beneficially affects meat quality of heat-stressed broilers which is associated with changes in muscle antioxidant status

L-Theanine attenuates oxidative damage induced by heat stress through the PI3K/AKT/Nrf2 signaling pathway in skeletal muscle cells

The rising prevalence of heat stress (HS), because of global warming, presents a considerable challenge to both human and animal health and welfare. L-Theanine (LTA), a naturally occurring amino acid, may enhance poultry muscle yield and quality, suggesting its potential application in alleviating the negative impacts of HS. However, the molecular mechanisms through which LTA exerts its beneficial effects remain to be fully understood. This study explored the protective effects of LTA on cultured broiler skeletal muscle cells under oxidative stress induced by HS, focusing on the molecular mechanisms involved. Our findings indicate that treatment with LTA significantly improved cell survival, bolstered the activity of antioxidant enzymes, decreased reactive oxygen species (ROS) contents and diminished malondialdehyde (MDA) levels in HS-treated cultured cells. Furthermore, LTA enhanced the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways in HS-treated cultured cells, facilitating mitochondrial biogenesis and reducing cell apoptosis. The protective effects of LTA in HS-treated cultured cells were significantly reduced by the PI3K inhibitor LY294002 or the Nrf2 inhibitor ML385. In conclusion, our study showed that LTA protects cultured skeletal muscle cells from HS-induced oxidative damage by modulating the PI3K/AKT/Nrf2 signaling pathway, positioning LTA as a promising natural antioxidant for poultry feed additives aimed at improving muscle health.

Dietary Tributyrin Improves Growth Performance, Meat Quality, Muscle Oxidative Status, and Gut Microbiota in Taihe Silky Fowls under Cyclic Heat Stress

Heat stress adversely affects poultry production and meat quality, leading to economic losses. This study aimed to investigate the effects of adding tributyrin on growth performance, meat quality, muscle oxidative status, and gut microbiota of Taihe silky fowls under cyclic heat stress (CHS) conditions. In this study, 120-day-old Taihe silky fowls (male) were randomly divided into six dietary treatments. These treatments included a normal control treatment (NC, fed a basal diet), a heat stress control treatment (HS, fed a basal diet), and HS control treatments supplemented with 0.04%, 0.08%, 0.16%, and 0.32% tributyrin, respectively. The NC treatment group was kept at 24 ± 1 °C, while the HS treatment birds were exposed to 34 ± 1 °C for 8 h/d for 4 weeks. Results showed that CHS decreased growth performance and compromised the meat quality of broilers (p < 0.05). However, tributyrin supplementation improved ADG and FCR in broilers exposed to CHS (p < 0.05). Additionally, tributyrin supplementation resulted in increased shear force value and GSH-Px activity, as well as a decrease in drip loss, ether extract content, and MDA content of the breast muscle in broilers under CHS (p < 0.05). Furthermore, tributyrin supplementation up-regulated the mRNA expressions of Nrf2, NQO1, HO-1, SOD, and GSH-Px of the breast muscle in broilers exposed to CHS (p < 0.05). Based on these positive effects, the study delved deeper to investigate the impact of 0.16% tributyrin supplementation (HS + 0.16%T) on the cecum microbiota. The HS + 0.16%T treatment showed an increase in the relative abundance of Rikenellaceae_RC9_gut_group (p < 0.05) and a trend towards an increase in Lactobacillus (p = 0.096) compared to the HS treatment. The results indicate that supplementation successfully improved the growth performance and meat quality of Taihe silky fowls. Furthermore, tributyrin supplementation, particularly at levels of 0.16%, improved meat quality by enhancing muscle antioxidant capacity, which is believed to be associated with activation of the Nrf2 signaling pathway.

Exercise Volume Provides New Insight into the Effects of Housing Systems on Chicken Body Conformation, Carcass Traits, Meat Quality, and Serum Biochemical Parameters

This study aims to investigate the dynamic changes in daily step counts under different housing systems and further explore the effects of housing system on the body conformation, carcass traits, meat quality, and serum biochemical parameters of a Chinese indigenous chicken breed. At 60 d of age, 300 Jiuyuan Black male chickens with similar body weights in each housing system were further raised until the age of 150 d. At 90, 120, and 150 d of age, in both cage-reared and free-range systems, the top 20 chickens with the highest step counts measured using pedometers and the bottom 20 chickens with the lowest step counts were designated as the cage high-steps group (CHS), the cage low-steps group (CLS), the free-range high-steps group (FHS), and the free-range low-steps group (FLS), respectively. The results show that, at any age stage, the average daily steps (ADS) and total steps (TS) of the FHS group are significantly higher than the other three groups (p < 0.05). The TS of almost all groups showed an overall downward trend as the age increased. Increased exercise volume results in reduced shank length (90 d), breast width (90 d), and keel length (150 d) (p < 0.05). Only birds at 90 d of age from the FHS and FLS groups exhibited lower live body weight, carcass weight, half-eviscerated weight, eviscerated weight, breast muscle weight, leg muscle weight, and percentage of eviscerated weight than the CLS group (p < 0.05). Birds from the FHS group showed the highest heart weight values but the lowest abdominal fat weight values among these four groups (p < 0.05). Both the breast and leg muscle samples from the FHS group displayed higher dry matter and shear force than those from the CHS and CLS groups (p < 0.05). The FHS group displayed the lowest intramuscular fat among the four groups (p < 0.05). The creatine kinase (CK) and lactate dehydrogenase (LDH) levels in chickens of all age stages were almost observed to rise with increased physical activity. In conclusion, free-range chickens with more exercise volume exhibited an elevated heart weight and reduced abdominal fat but showed negative effects on some body measurements and carcass traits. These results can provide a theoretical basis for the selection of different housing systems for Chinese indigenous chickens.

Dietary pterostilbene exerts potential protective effects by regulating lipid metabolism and enhancing antioxidant capacity on liver in broilers

Intensive breeding of broilers met the increasing demands of human for broiler products, but it raised their increased susceptibility to various stressors resulting in the disorder of lipid metabolism. Pterostilbene, the methoxylated analogue of resveratrol, exhibits astonishing functions of antioxidant, anti-inflammatory and glycolipid regulatory. The study aimed to elucidate the protective effects of pterostilbene on broiler liver and to explore the potential mechanisms. A total of 480 one-day-old male Arbor Acres (AA) broilers were randomly divided into four groups: the control group (basal diet) and pterostilbene groups (PT200, PT400, and PT600 feeding with basal diet containing 200, 400 and 600 mg/kg pterostilbene, respectively). The results showed that the dietary pterostilbene supplementation significantly improved the ADG of broilers. Dietary pterostilbene supplementation regulated the expression levels of the genes Sirt1 and AMPK and the downstream genes related to lipid metabolism to protect liver function and reduce lipid accumulation in broilers. Dietary pterostilbene supplementation upregulated the expression levels of the Nrf2 gene and its downstream antioxidant genes (SOD, CAT, HO-1, NQO-1, GPX) and phase II detoxification enzyme-related genes (GST, GCLM, GCLC). Collectively, pterostilbene was confirmed the positive effects as a feed additive on lipid metabolism and antioxidant via regulating Sirt1/AMPK and Nrf2 signalling pathways in broilers.

Effects of dietary tryptophan supplementation on rectal temperature, humoral immunity, and cecal microflora composition of heat-stressed broilers

This trial aimed to determine the effects of tryptophan (Trp) on the rectal temperature, hormone, humoral immunity, and cecal microflora composition in broiler chickens under heat stress (HS). One hundred and eighty 18 days-old female Arbor Acres broilers were randomly divided into three treatment groups, with six replicates of ten birds in each replicate. The broilers were either raised under thermoneutral conditions (TN, 23 ± 1°C) or subjected to heat stress (34 ± 1°C for 8 h daily). The TN group received a basal diet, and another two heat-stressed groups were fed the basal diet (HS) or the basal diet supplemented with 0.18% Trp (HS + 0.18% Trp) for 21 consecutive days. The basal diet contained 0.18% Trp. Results revealed that HS increased the rectal temperature, serum epinephrine (EPI), and corticotropin-releasing hormone (CRH) concentrations (p < 0.05), reduced the bursal index, the levels of serum immunoglobulin A (IgA), IgG, IgM, and serotonin (5-HT) as well as the relative abundance of Actinobacteria in cecum (p < 0.05) compared with the TN group. Dietary supplementation of Trp decreased the rectal temperature, serum dopamine (DA), EPI, and the levels of CRH and L-kynurenine (p < 0.05), increased the bursal index, the levels of serum IgA, IgM, and 5-HT as well as the relative abundance of Ruminococcus torques group in cecum of heat-stressed broilers (p < 0.05) compared to HS group. In conclusion, dietary Trp supplementation decreased rectal temperature, improved cecal microbiota community and Trp metabolism, and enhanced humoral immunity of heat-stressed broilers.

Comprehensive review of resveratrol as a feed additive in dairy cows: exploring its potential diverse effects and implications

Heat stress and growing demand for dairy products in tropical regions exert metabolic pressure on dairy cows, leading to metabolic diseases and economic losses. Resveratrol (RSV) is known for its numerous beneficial health effects and can be used as a barrier against metabolic abnormalities and prevent economic losses. Several studies have investigated the effects of RSV in humans and various animal species. In this review, we attempted to investigate the effects of RSV from different aspects so that we could have a practical proposal for its utilization in dairy cows. RSV was found to have potential antioxidant, anti-inflammatory, anti-obesity, and antimicrobial effects, leading to improved reproductive performance. It is interesting that the effect of RSV on the microbial population leads to a significant decrease in methane emissions. However, high doses of RSV have been associated with possible adverse effects, underscoring the dose dependence of its efficacy. In conclusion, RSV polyphenol at optimal doses is a promising agent for the prevention and treatment of metabolic abnormalities in dairy cows, based on our literature review and study results.

Surviving high temperatures: a case study of the spotted munia (Lonchura punctulata)

Every year, a combination of summer with extreme weather events such as "heatwaves" affects the life of organisms on earth. Previous studies on humans, rodents, and some birds signify the impact of heat stress on their survival and existence. Over the past four decades, the frequency of heatwaves has increased because of global warming. Therefore, we performed a longitudinal study on a resident bird species, the spotted munia (Lonchura punctulata) by simulating a heatwave-like condition. We were interested in understanding how a Passeriformes native to a sub-tropical country deals with heatwave-like conditions. Initially, the birds were subjected to room temperature (25 ± 2 °C; T1) for 10 days, followed by a simulated heatwave-like condition (42 ± 1 °C; T2) for 7 days and again back to room temperature (25 ± 2 °C; RT1) for the next 7 days. To elucidate how birds cope with simulated heatwave conditions, we examined different behavioral and physiological parameters. We found that although heat stress significantly reduced total activity counts and food intake but, the body mass, blood glucose, and hemoglobin levels remained unaffected by any of the temperature conditions. Furthermore, HSP70 and biochemical markers of liver injuries such as ALP, AST, ALT, bilirubin direct, and bilirubin total were found elevated in response to the simulated heatwave-like condition, whereas uric acid and triglyceride were reduced. Creatinine and total protein levels were unaffected by the heatwave. The post heatwave treatment resulted in a rebound of the behavioral and physiological responses, but the recovered responses were not equivalent to the pre-heatwave levels (T1 conditions). Thus, the present study demonstrates heatwave-associated behavioral and physiological changes in a resident passerine finch which has tremendous physiological flexibility.

Biological function of resveratrol and its application in animal production: a review

With the prohibition of antibiotics in feed, plant functional substances have been widely studied as feed additives. Resveratrol, a natural stilbene, and a non-flavonoid polyphenol found in plants, possesses antioxidant, anti-inflammatory, and metabolic regulatory features. Resveratrol generated intense scientific and public interest, primarily due to its widely reported ability to prevent cancer, delay aging and alleviate related metabolic diseases. Recently, resveratrol has been studied and applied as a feed additive in animal production. This review focuses on the outline of the absorption and metabolism and biological functions of resveratrol and summarizes the application of dietary resveratrol in animal production up to the present, including pigs, poultry, and ruminants. In pigs, dietary resveratrol improved intestinal health, mitochondrial function, meat quality, and more. In poultry, studies have shown that dietary resveratrol improves growth performance and meat and egg quality and alleviates heat stress induced adverse effects. There are few studies on dietary resveratrol in ruminants; however previous studies have indicated that dietary resveratrol increases nutrient digestibility and reduces methane emissions in sheep. It is hoped that this review could provide a specific theoretical basis and research ideas for the research and application of resveratrol.

Dietary supplementation with chia polyphenols alleviates oxidative stress and improves egg nutritional quality in Japanese quails under heat stress

Heat stress in poultry is a major concern, especially in regions with hot summers and scarce cooling infrastructure. Dietary supplementation with antioxidants, such as polyphenols, has risen as a strategy to mitigate the physiological consequences of heat stress. A by-product of the extraction of oil from chia seeds, which is discarded if not used, could be a possible source of polyphenols. The aim of the present study was to evaluate the effects of dietary supplementation with polyphenols from defatted chia seed cake on the general performance, and oxidative status of Japanese quail exposed to heat stress. Furthermore, productive performance, egg quality and yolk fatty acid composition were also assessed. A total of 36 females (96 days of age) were randomly assigned to different diets: BASAL (control), LDCP (low dose of chia polyphenols), or HDCP (high dose of chia polyphenols). Half the animals in each diet group were exposed to 34 °C for 9 h a day (Heat Stress; HS), while the other half remained at the standard 24 °C (No Heat Stress; NHS). After 23 days of experimental conditions, animals under HS showed higher body temperatures and time spent panting, but lower egg laying rate. Moreover, HS modulated the activity of catalase and glutathione peroxidase enzymes, increasing lipid peroxidation in serum and liver; and increased saturated fatty acids in egg yolk. Supplementation with chia polyphenols helped to mitigate the HS effects, especially on glutathione peroxidase activity, decreasing lipid peroxidation. In addition, supplementation with HDCP showed the highest proportion of polyunsaturated fatty acids in liver and egg yolk. In conclusion, the use of defatted chia seed cake could represent a sustainable strategy to mitigate heat stress effects on Japanese quail, due to its capacity to decrease oxidative stress and improve the nutritional quality of egg, while decreasing the amount of waste generated by the food industry.

Resveratrol relieves chronic heat stress-induced liver oxidative damage in broilers by activating the Nrf2-Keap1 signaling pathway

Heat stress (HS) affects poultry production and welfare, causing enormous damage to poultry. Resveratrol, an antioxidant and anti-inflammatory natural plant polyphenol, is widely used in agriculture for the prevention of oxidative stress-related diseases. This study aimed to explore the effects and potential mechanism of resveratrol on liver oxidative damage in heat-stressed broilers. Sixty SPF chickens were randomly divided into control, heat stress (HS) and HS+ resveratrol (resveratrol) groups. Broilers were exposed to 35 ± 2 ℃ (8 h/d) for 7 consecutive days to induce HS, and the other 16 h/d were kept at 23 ± 2 ℃, similar to the control group. Broilers received 400 mg/kg resveratrol in the basic diet 2 days before exposure to HS and for the following 7 days. The results showed that resveratrol improved growth performance by increasing the average daily gain (ADG) and reducing the feed conversion ratio (FCR), compared with the HS group. Heat stress reduced liver weight and index, increased inflammatory cell infiltration in the liver, enhanced serum AST levels, and decreased TP and ALB II levels, which resulted in liver injury in broilers, and resveratrol effectively alleviated liver injury. Moreover, supplementation with resveratrol enhanced the activities of liver antioxidant enzymes resulting in higher GPX and SOD levels than those in the heat-stressed broilers, and decreased MDA levels. Furthermore, resveratrol alleviated liver oxidative stress by activating the gene and protein levels of Nrf2 and HO-1, enhancing NQO1 and SOD1 gene levels, and decreasing protein levels of HSP70, p62, and Keap1, and thereby alleviated the liver injury of heat-stressed broilers. Compared with the HS group, Nrf2 immunofluorescence was significantly up-regulated in the livers of resveratrol group. These results suggest that resveratrol can enhance the liver antioxidant function by activating the Nrf2-Keap1 signaling pathway to promote growth performance in broilers under HS.

Effect of dietary resveratrol supplementation on growth performance, antioxidant capacity, intestinal immunity and gut microbiota in yellow-feathered broilers challenged with lipopolysaccharide

Resveratrol (RES) displays strong antioxidant and anti-inflammatory properties in protecting the animals from various stressors and inflammatory injuries, but its interrelationship with the gut microbiota remained largely unclear. This study was carried out to investigate the effects of dietary RES supplementation on growth performance, antioxidant capacity, intestinal immunity and gut microbiota in yellow-feathered broilers challenged by lipopolysaccharide (LPS). A total of 240 yellow-feathered broilers were randomly assigned to four treatment groups in a 2 × 2 factorial design. The broilers were fed with the control diet or control diet supplemented with 400 mg/kg RES, followed by challenge with LPS or the same amount of saline. Dietary RES supplementation significantly alleviated the decreases in the final body weight (BW), average daily gain (ADG), and ADFI induced by LPS (P &lt; 0.05). LPS challenge significantly increased plasma concentrations of triglyceride, high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), and cortisol levels, but decreased triiodothyronine (T3) and insulin levels (P &lt; 0.05). Dietary supplementation with RES significantly reversed the elevated creatinine concentrations and the decreased concentrations of T3 and insulin caused by LPS (P &lt; 0.05). Moreover, dietary RES supplementation significantly increased plasma total antioxidant capacity (T-AOC) and catalase (CAT) activities and superoxide dismutase (SOD) and T-AOC activities in jejunal mucosa and reduced malondialdehyde (MDA) concentration in the plasma (P &lt; 0.05). The reduction in the villus height to crypt depth ratio in duodenum, jejunum and ileum and the shortening of villus height in jejunum and ileum caused by LPS were also alleviated by RES treatment (P &lt; 0.05). Furthermore, the increased concentrations of intestinal tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β caused by LPS were significantly decreased by RES treatment (P &lt; 0.05). Dietary RES treatment increased the mRNA expression of claudin-1, claudin-5, occludin, and zonula occludens-1 (ZO-1), and decreased mRNA expression of IL-1β, IL-8, IL-17, and TNF-α after LPS challenge (P &lt; 0.05). Dietary RES treatments significantly decreased the dominance of cecal microbiota, and increased the Pieiou-e and Simpson index. Moreover, dietary RES supplementation increased relative abundance of UCG_ 009, Erysipelotrichaceae, Christensenellaceae_R-7_group, Anaerotruncus, RF39, and Ruminococcus while decreasing the abundance of Alistipes at genus level. Spearman correlation analysis revealed that the microbes at the order and genus levels significantly correlated with indicators of growth performance, antioxidant capacity, and intestinal health. Collectively, dietary supplementation with 400 mg/kg RES could improve growth performance and antioxidant capacity, and modulate intestinal immunity in yellow-feathered broilers challenged by LPS at early stage, which might be closely associated with the regulation of gut microbiota community composition.

Resveratrol Attenuates Heat Stress-Induced Impairment of Meat Quality in Broilers by Regulating the Nrf2 Signaling Pathway

Studies have indicated that dietary resveratrol (RES) improves the meat quality of broilers subjected to heat stress (HS), but the mechanism of action remains unclear. Therefore, the main purpose of this study was to investigate the effect of RES on meat quality, muscle antioxidant status, and its mechanism of action in broilers under HS. A total of 162 male AA broilers at 21 days old with similar weight were randomly assigned to 3 treatment groups with 6 replicates each. The control group (ambient temperature: 22 ± 1 °C) and HS group (ambient temperature: 33 ± 1 °C for 10 h a day from 8:00 to 18:00 and 22 ± 1 °C for the remaining time) were fed a basal diet and the HS + RES group was fed a basal diet with 400 mg/kg RES. The feeding was conducted for 21 continuous days. The results indicated that HS decreased final body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), breast and leg muscle yield, a*24h, pH24h, the activities of catalase (CAT), glutathione S-transferase (GST) and glutathione peroxidase (GSH-Px), and mRNA levels of nuclear factor erythroid 2−related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase 1 (NQO1), and GSH-Px (p < 0.05). HS also increased b*45min, L*24h, drip loss, malondialdehyde (MDA) content, and kelch-like epichlorohydrin-associated protein 1 (Keap1) mRNA level (p < 0.05). Compared with the HS group, the HS + RES group exhibited a higher ADG, breast and leg muscle yield, a*24h, pH24h, activities of GST and GSH-Px, and mRNA levels of Nrf2, HO-1, and NQO1 but had lower drip loss and Keap1 mRNA level (p < 0.05). RES can improve meat quality and the muscle antioxidant ability of heat-stressed broilers by activating the Nrf2 signaling pathway.

Protective Effects and Potential Mechanisms of Dietary Resveratrol Supplementation on the Spleen of Broilers Under Heat Stress

Resveratrol (RSV) is a natural polyphenolic compound with potent antioxidant and anti-inflammatory properties. This study aimed to investigate the protective effects of RSV supplementation on the inflammatory responses of broilers during heat stress. A total of 432 28-d-old white-feathered broilers (817 crossbred chicken) with an average weight of 549 ± 4 g were randomly allotted to 4 equal groups (Half male and half female, 6 replicates/group, 18 chickens/replicate), including normal temperature (NT) group (24 ± 2°C for 24 h/d, basal diet), NT+RSV group (24 ± 2°C for 24 h/d, basal diet + RSV), heat stress (HT) group (37 ± 2°C for 8 h/d, basal diet), and HT+RSV group (37 ± 2°C for 8 h/d, basal diet + RSV). Serum samples were collected on d 7 and 14 of heat stress, and thymus, spleen, jejunum, and bursa of Fabricius samples were collected and analyzed on d14. RSV treatment decreased the feed conversion ratio, partially reversed the negative alternations in body weight, average daily gain, and average daily feed intake caused by heat stress. RSV treatment also decreased the elevated levels of corticosterone on d 14, adrenocorticotropic hormone, and triiodothyronine in serum on d 7 caused by heat stress, and significantly increased the villus height to crypt depth ratio in the jejunum on d 14. Dietary RSV also reduced heat stress-induced splenic pro-inflammatory cytokine concentrations. TUNEL assay showed that RSV significantly reduced heat stress-induced the number of apoptotic cells. Remarkably, RSV down-regulated some splenic related genes for apoptosis genes, including BCL-2, Apaf-1, and MDM2 mRNA levels induced by heat stress. According to GO and KEGG enrichment analyses, the differential genes between HT and HT + RSV groups were mainly associated with immune system process, hematopoietic or lymphoid organ development, and toll-like receptor signaling pathway. The relative mRNA expression of NF-κB, heat shock protein 70 (HSP70), and p38 MAPK were markedly decreased by the combination of RSV and heat stress. These findings showed that RSV might reduce the splenic inflammatory response in heat-stressed white-feather broilers by inhibiting heat stress-induced activation of NF-B, MAPK, and HSP70, as well as inhibiting the activation of mitochondrial apoptotic pathways.

Effect of coconut water and milk on heat stress-induced gastrointestinal tract dysmotility in rats: Role of oxidative stress and inflammatory response

The potential effects of coconut water (CCW) and milk (CCM) on gastrointestinal motility {intestinal transit (IT), intestinal fluid accumulation (IFA) and colonic motility}, tissue oxidative, and inflammatory responses in heat-stressed rats were investigated. There were four (4) temperature exposure groups; (i) Control at 30°C, (CON), (ii) heat-stressed (HS) group exposed to the ambiance of 40°C, (iii) heat-stressed pre-treated with coconut water (HS+ CCW), and (iv) coconut milk (HS + CCM). Skin temperatures (ST) and rectal temperatures (RT) were taken daily, before and after 2 hr heat exposure. GE, IT, and IFA were assessed using standard methods while colonic motility was assessed by colonic bead expulsion (CBE) time after the 14-day exposure. Serum cortisol and lipid peroxidation, antioxidant enzyme activities, inflammatory cytokines in intestinal samples were assessed. Stomach and intestinal morphology were equally examined on histomorphometry. Increased GE, IT, IFA, and colonic motility were observed in HS. CCW and CCM reversed the increases in GE, IT, IFA, and colonic motility in the heat-stressed rats (p < .05). Elevated serum cortisol level and intestinal MDA were significantly reduced in the CCW and CCM treated. Tissue GPx, T-AOC, and T-SOD were all enhanced in HS + CCW and HS + CCM. While tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were suppressed in the HS group, interleukin-4 (IL-4) and interleukin-10 (IL-10) were enhanced with CCW and CCM. Altered intestinal morphology in the HS was also significantly mitigated by CCW and CCM. We showed that coconut water and milk could ameliorate intestinal dysmotility associated with heat stress via oxidative stress reduction and suppression of inflammatory responses. PRACTICAL APPLICATIONS: Heat stress impacts negatively on intestinal health and integrity in both humans and animals via oxidative stress and inflammation. Conversely, coconut has demonstrated anti-oxidative and anti-inflammatory properties in health and medicinal applications. From the findings of this study, coconut water and milk display beneficial potentials against the untoward heat stress effect on gastrointestinal health.

The Effect of Dietary Supplementation with Resveratrol on Growth Performance, Carcass and Meat Quality, Blood Lipid Levels and Ruminal Microbiota in Fattening Goats

This study investigated the effects of resveratrol (RES) supplementation on the growth performance, carcass and meat quality, blood lipid levels and ruminal bacterial microbiota of fattening goats. A total of forty castrated Nubian goats (28.25 ± 0.26 kg body weight) were randomly divided into four groups and provided with diets containing different levels of RES (0, 150, 300 and 600 mg/kg) for 120 d. The results showed that RES increased redness and intramuscular fat content, whilst reducing shear force in the longissimus dorsi muscle of goats (p < 0.05). In addition, the final weight, average daily gain, hot carcass weight, net meat weight, carcass lean percentage and eye muscle area of goats were significantly increased in the 150 mg/kg RES group compared with the other three groups, while those in the 600 mg/kg RES group significantly decreased (p < 0.05). RES significantly decreased serum triacylglycerol and LDL-C contents (p < 0.05), and increased HDL-C content and the HDL-C/TC ratio (p < 0.05). Supplementation with 150 mg/kg RES also increased the proportion of Acetitomaculum and Moryella, genera comprising short-chain fatty acid-producing bacteria. The present study indicated that an appropriate supplemental level of RES could improve the growth performance, neat percentage, meat quality, ruminal microbiota and serum lipid levels of fattening goats.

Integrated Analysis of mRNA and MicroRNA Co-expressed Network for the Differentiation of Bovine Skeletal Muscle Cells After Polyphenol Resveratrol Treatment

Resveratrol (RSV) has been confirmed to benefit human health. Resveratrol supplemented in the feeds of animals improved pork, chicken, and duck meat qualities. In this study, we identified differentially expressed (DE) messenger RNAs (mRNAs) (n = 3,856) and microRNAs (miRNAs) (n = 93) for the weighted gene co-expression network analysis (WGCNA) to investigate the co-expressed DE mRNAs and DE miRNAs in the primary bovine myoblasts after RSV treatment. The mRNA results indicated that RSV treatments had high correlations with turquoise module (0.91, P-value = 0.01) and blue module (0.93, P-value < 0.01), while only the turquoise module (0.96, P-value < 0.01) was highly correlated with the treatment status using miRNA data. After biological enrichment analysis, the 2,579 DE genes in the turquoise module were significantly enriched in the Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The top two GO terms were actin filament-based process (GO:0030029) and actin cytoskeleton organization (GO:0030036). The top two KEGG pathways were regulation of actin cytoskeleton (bta04810) and tight junction (bta04530). Then, we constructed the DE mRNA co-expression and DE miRNA co-expression networks in the turquoise module and the mRNA–miRNA targeting networks based on their co-expressions in the key module. In summary, the RSV-induced miRNAs participated in the co-expression networks that could affect mRNA expressions to regulate the primary myoblast differentiation. Our study provided a better understanding of the roles of RSV in inducing miRNA and of the characteristics of DE miRNAs in the key co-expressed module in regulation of mRNAs and revealed new candidate regulatory miRNAs and genes for the beef quality traits.

Chitosan oligosaccharides alleviate acute heat stress-induced oxidative damage by activating ERK1/2-mediated HO-1 and GSH-Px gene expression in breast muscle of broilers

The purpose of this study was to evaluate the effects of chitosan oligosaccharides (COS) on acute heat stress (AHS) induced poor meat quality by alleviating oxidative damage through mitogen-activated protein kinase-nuclear factor-erythroid 2-related factor 2-antioxidant responsive element (MAPK-Nrf2-ARE) signaling pathway. A total of 108 thirty-five-day-old Chinese indigenous broilers (Luhua chicken) was used for this 42-d experiment. The broilers were randomly allocated to 3 treatments: control group (CON), AHS group, and AHS with 400 mg/kg COS supplementation (AHS-C) group. Both CON and AHS groups given the basal diet, and the AHS-C group given the basal diet with 400 mg/kg COS supplementation. On d 42, broilers in the AHS and AHS-C groups treated with AHS (increasing temperature from 24 to 34°C in 2-h and held for another 2-h), and the CON group under normal temperature (24°C). AHS exposure elevated (P < 0.05) body temperature (rectal, comb, eyelids, and feet) of broilers, increased (P < 0.05) breast muscle lightness (L*), drip loss, share force, hydrogen peroxide (H₂O₂) scavenging activity, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and catalase (CAT) activity, however, decreased (P < 0.05) pH_45min, pH_24h, redness (a*), and relative expression of heme oxygenase-1 (HO-1). Compared to the AHS group, dietary COS supplementation increased (P < 0.05) breast muscle pH_45min, pH_24h, and a*, H₂O₂ scavenging activity, as well as relative expression of HO-1 and glutathione peroxidase (GSH-Px), however, decreased (P < 0.05) drip loss, share force, superoxide anion free radicals (O₂^•−) scavenging activity, ROS production, and MDA content. It was concluded that AHS impaired meat quality, which may be related to oxidative damage, as evidenced by increasing ROS production, MDA content, and decreasing the relative expression of HO-1. Dietary COS supplementation could effectively elevate the meat quality of broilers exposed to AHS via decreasing ROS production, activating the Nrf2 pathway, and Nrf2-mediated HO-1 and GSH-Px gene expression.

Effects of Dietary Supplementation with Epigallocatechin Gallate on Meat Quality and Muscle Antioxidant Capacity of Broilers Subjected to Acute Heat Stress

Simple Summary

Broilers are readily affected by acute heat stress (AHS), and the development of intensive and high-density management and the occurrence of high temperatures during the summer exacerbate this problem. AHS has undesirable effects on animal immunity, meat quality, antioxidant capacity, and welfare of broilers, which can be alleviated by nutrition regulation. Epigallocatechin gallate (EGCG) has been found to reduce the damage of AHS on growth performance, antioxidant capacity, and the expression of nuclear factor erythroid 2-related 2 (Nrf2) in liver and jejunum. However, there are few reports on the effect and mechanism of action of EGCG on meat quality and antioxidant function in broilers under AHS. We demonstrated that EGCG protects against AHS-impaired meat quality by improving muscle antioxidant capacity, which seems to be associated with the activation of the Nrf2 signaling pathway. Moreover, these findings suggested that EGCG could be an effective additive to improve meat quality and muscle redox balance by regulating the Nrf2 signaling pathway.

Abstract

This study evaluated epigallocatechin gallate’s (EGCG’s, 400 mg/kg) effect on meat quality and muscle antioxidant status of broilers under acute heat stress (AHS). A total of 144 21-day-old male Huainan partridge chickens were randomly allocated to the EGCG-free group (12 replicates) and the EGCG group (6 replicates). On day 94, the EGCG-free group was divided into the control group (CON) and the AHS group, and then AHS group and EGCG group (identified as AHS + EGCG group) were treated with AHS (33 ± 1 °C for 12 h). AHS increased (p < 0.05) L*_24h, drip loss, muscle lactic acid, malondialdehyde (MDA) contents, and kelch-like ECH-associated protein 1 (Keap1) mRNA level, and decreased (p < 0.05) eviscerated percentage, pH_24h, a*, muscle total superoxide dismutase (T-SOD) activity, the ratio of T-SOD/MDA and glutathione peroxidase /MDA, glycogen content, and nuclear factor erythroid 2-related 2 (Nrf2), catalase (CAT), NAD(P)H/quinone dehydrogenase 1 (NQO1) mRNA levels. The AHS + EGCG group exhibited lower (p < 0.05) L*_24h, drip loss, muscle lactic acid, MDA contents and Keap1 mRNA level, and greater (p < 0.05) eviscerated percentage, pH_24h, a*, muscle T-SOD activity, the ratio of T-SOD/MDA, Nrf2, and NQO1 mRNA levels compared with the AHS group. In conclusion, EGCG protects against AHS-impaired meat quality by improving muscle antioxidant capacity, which seems to be associated with the activation of the Nrf2 signaling pathway.

Meta-analysis to predict the effects of temperature stress on meat quality of poultry

Temperature stress (TS) is a significant issue in poultry production, which has implications for animal health and welfare, productivity, and industry profitability. Temperature stress, including both hot (heat stress) and cold conditions (cold stress), is associated with increased incidence of meat quality defects such as pale, soft, and exudative (PSE) and dark, firm, and dry (DFD) meat costing poultry industries millions of dollars annually. A meta-analysis was conducted to determine the effect of ambient TS on meat quality parameters of poultry. Forty-eight publications which met specific criteria for inclusion were identified through a systematic literature review. Temperature stress was defined by extracting 2 descriptors for each treatment mean from the chosen studies: (1) temperature imposed for the experimental treatments (°C) and duration of temperature exposure. Treatment duration was categorized for analysis into acute (≤24 h) or chronic (>24 h) treatments. Meat quality parameters considered were color (L*-a*-b* scheme), pH (initial and ultimate), drip loss, cooking loss, and shear force. Linear mixed model analysis, including study as a random effect, was used to determine the effect of treatment temperature and duration on meat quality. Model evaluation was conducted by performing a k-fold cross-validation to estimate test error, and via assessment of the root mean square prediction error (RMSPE), and concordance correlation coefficient (CCC). Across both acute and chronic durations, treatment temperature was found to have a significant effect on all studied meat quality parameters. As treatment temperature increased, meat demonstrated characteristics of PSE meat and, as temperature decreased, meat demonstrated characteristics of DFD meat. The interaction between treatment temperature and duration was significant for most traits, however, the relative impact of treatment duration on the studied traits was inconsistent. Acute TS had a larger effect than chronic TS on ultimate pH, and chronic stress had a more considerable impact on color traits (L* and a*). This meta-analysis quantifies the effect of ambient TS on poultry meat quality. However, quantitative effects were generally small, and therefore may or may not be of practical significance from a processing perspective.

Dietary supplementation of Solanum aethiopicum and Solanecio biafrae leaves alters stress and immune responses, antioxidant status, and meat quality in broilers raised in a hot-dry environment

1. This study investigated the influence of dietary supplementation of Solanum aethiopicum and Solanecio biafrae leaves, which have nutraceutical properties, on stress response, cytokine expression, antioxidant status, blood chemistry, abdominal fat and meat quality in broilers reared in a hot, dry environment.2. One day old, Ross 308 chicks (n = 350) were randomly allotted to basal diets containing either no supplement (D1); 2.5 g/kg Solanum aethiopicum leaf (SAL; D2); 5 g/kg SAL (D3); 2.5 g/kg Solanecio biafrae leaf (SBL; D4); or 5 g/kg SBL (D5) for 42 d. Birds were reared at 34 ± 2°C and 40-50% relative humidity for 6 h/d from 22-42 d. Each dietary group was replicated in seven pens containing 10 chicks.3. In the period 1-21 d, body weight gain, feed efficiency and feed intake were not influenced by diet. At 22-42 and 1-42 d, birds supplemented with SAL and SBL had higher (P < 0.05) body weight gain and feed efficiency than the D1 birds. Cloaca temperature, carcase cuts and relative organ weight did not differ between diets. The D3 birds had higher (P < 0.05) erythrocytes and haemoglobin compared with other birds. Dietary supplements reduced (P < 0.05) mortality, abdominal fat, serum total cholesterol, corticosterone, glucose and blood aspartate aminotransferase levels.4. The treatments up-regulated (P < 0.05) splenic intelukin-10, and down-regulated (P < 0.05) tumour necrosis factor-α and interleukin-1β genes. A dose-dependent improvement (P < 0.05) in antioxidant enzyme activities and total antioxidant capacity of serum and breast muscle were found in the supplemented birds. The breast meat of the supplemented birds had lower (P < 0.05) carbonyl and malondialdehyde contents, and higher (P < 0.05) water holding capacity and redness compared with the non-supplemented meat.5. These results illustrated that supplementation with either 5 g/kg SAL or 5 g/kg SBL attenuated the deleterious effects of heat stress in broiler chickens.

Effects of Resveratrol on Growth Performance, Intestinal Development, and Antioxidant Status of Broilers under Heat Stress

Simple Summary

Broilers have unique physiological characteristics, no sweat glands and full of feathers, which makes it difficult to dissipate heat in high-temperature environments and is prone to heat stress (HS). HS has strong adverse effects on the meat production, growth performance, intestinal morphology, mortality and welfare of broilers, which can be alleviated by nutrition regulation. Resveratrol has been found to reduce the damage of HS on meat quality, immune and inflammatory response of broilers. However, there are few reports on the effects of resveratrol on the intestinal development and antioxidant capacity of broilers under HS. We demonstrated that resveratrol could improve the intestinal development and growth performance of broilers under HS. Besides, these findings suggest that resveratrol may offer an effective nutritional strategy to improve intestinal antioxidant function by regulating the expression of critical factors in the Nrf2 signaling pathway.

Abstract

The study investigated resveratrol’s effect on growth performance, intestinal development, and antioxidant capacity of broilers subjected to heat stress (HS). A total of 162 21-day-old male AA broilers were randomly divided into 3 treatment groups with 6 replicates of 9 birds each. The 3 treatment groups were as follows: the control (CON), in which broilers were housed at 22 ± 1 °C for 24 h day⁻¹, and the HS and HS + resveratrol (400 mg/kg) groups, in which broilers were housed at 33 ± 1 °C for 10 h a day from 8:00 to 18:00 and 22 ± 1 °C for rest of the time. Results indicated that birds in the HS group exhibited lower (p < 0.05) final body weight (BW) and average daily gain (ADG) compared with birds in the CON group. HS birds also had lower (p < 0.05) relative jejunum weight, relative ileum and jejunum length, jejunal villus height, and villus height to crypt depth ratios than the CON group. The activities of glutathione peroxidase (GPX), glutathione S-transferase (GST), superoxide dismutase (SOD), and the mRNA levels of NF-E2-related factor 2 (Nrf2), SOD1, and GPX were also lower (p < 0.05) in the HS than CON group. The HS group had higher (p < 0.05) protein carbonyl (PC) contents and Kelch-like ECH-associated protein 1 (Keap1) mRNA levels. Compared with HS group, the HS + resveratrol group exhibited higher (p < 0.05) BW and ADG, relative jejunum weight, relative length of ileum, jejunal villus height, activities of GPX and GST, and mRNA levels of Nrf2 and SOD1, but they had lower (p < 0.05) PC content and Keap1 mRNA levels. In conclusion, resveratrol can improve the intestinal development and antioxidant function of broilers under HS, and therefore improve growth performance. The mechanism by which resveratrol enhances the intestinal antioxidant capacity is mediated by Nrf2 signaling pathway.

Exercise profile and effect on growth traits, carcass yield, meat quality, and tibial strength in Chinese Wannan chickens

The aim of the study was to understand the dynamic changes in daily step counts (DSC) during the development of chickens and to further explore the effects of exercise on the growth performance, carcass yield, meat quality, and tibial strength of cocks. A total of 600 (half male and half female) 1-day-old Wannan chickens with similar hatching weights were raised under the same rearing conditions. All birds were wing banded and housed in identical cages for from 1 to 8 wk in the experimental poultry house. The dimensions of the cages were 70 × 70 × 40 cm (length × width × height). At the age of 9 to 16 wk, these birds were reared in indoor pens (2 m × 2 m, 1,000 cm² per bird). In addition, they also had a free-range grass paddock (20 m × 30 m, 1 m² per bird). The DSC of male and female Wannan chicks were recorded from 70 to 112 d by using a pedometer. At 112 d of age, based on the average DSC, birds were divided into groups representing the highest (HS), medium, and lowest (LS) number of step groups. Fifteen cocks from each group were selected for subsequent experiments. Compared with the LS group, the HS group displayed higher tibial strength (P = 0.025) and lower BW, cooking loss (P = 0.014), shear force (P = 0.023), and drip loss (P = 0.008). The DSC had no effects on the female BW or male carcass parameters. There was no significant change in the DSC of all birds from 70 to 112 d. However, male chickens took more steps than females at 15 (P = 0.025) and 16 (P = 0.012) week of age. In conclusion, the effects of the DSC on the BW of Wannan chickens depend on sex, and enhanced exercise could improve the meat quality and tibial strength of cocks.

Effects of chitosan oligosaccharides on meat quality, muscle energy metabolism and anti-oxidant status in broilers that have experienced transport stress

Context Pre-slaughter transport, exposed broilers to various stressors, which resulted in detrimental effects on animal welfare, live bodyweight loss, mortality and meat quality. There was growing interest to explore effective ways to reduce the stress response and improve meat quality of transported broilers by using dietary feed additives. Aims The purpose of the present study was to investigate the effect of chitosan oligosaccharides (COS) on meat quality, muscle energy metabolism and anti-oxidant status of broilers having 3-h transport stress. Methods In total, of 144 35-day-old broilers were randomly allocated to two dietary treatments, including a basal diet (96 broilers), or basal diet supplemented with COS at 200 mg/kg (48 broilers). There were eight broilers per cage, and 12 replication cages in the basal diet group and six replication cages in the basal diet with 200 mg/kg COS group. At the end of the experiment, after a 12-h fast, broilers in the basal diet group were randomly divided into two groups, with six replication cages in each group; then, the broilers were transported as per the following protocols: broilers in the basal diet group (CON group) were without transport stress; broilers in the basal diet group with 3 h of transport stress (TS group), and broilers in the basal diet with 200 mg/kg COS supplementation and 3 h of transport stress (TSC group). The serum corticosterone concentration, serum, liver and muscle anti-oxidant status, as well as meat quality and muscle energy metabolism were analysed. Key results Compared with the CON group, TS group showed increased bodyweight loss, serum corticosterone concentration, breakdown of muscle glycogen, increased muscle lactate dehydrogenase activity, as well as some changes of body anti-oxidant status (higher serum, liver and muscle MDA concentrations, lower serum SOD and GSH-Px, liver SOD and CAT, and lower muscle SOD, GSH-Px, and CAT activity), accompanied with lower pH45min and pH24h. Nevertheless, compared with the TS group, dietary COS supplementation reduced bodyweight loss, decreased muscle MDA concentration, increased muscle SOD and CAT activity, and was accompanied with improving pH24h. Conclusions The results suggested that the positive effects of dietary COS supplementation in maintaining meat quality were mainly due to the improved muscle anti-oxidant status. Implications Dietary supplementation with 200 mg/kg COS could serve as a beneficial and effective way to alleviate transport-impaired meat quality of broilers.

Changes in facial surface temperature of laying hens under different thermal conditions

OBJECTIVE

The purpose of this study was to identify through infrared thermal imaging technology the facial surface temperature (FST) of laying hens in response to the variations in their thermal environment, and to identify the regional differences in FST to determine the most stable and reliable facial regions for monitoring of thermoregulatory status in chickens.

METHODS

Thirty Hy-Line Brown hens (25-week-old) were sequentially exposed to three different thermal conditions; optimal (OT, 22°C±2°C), low (LT, 10°C±4°C), and high temperature (HT, 30°C±2°C). The mean values of FST in five facial regions including around the eyes, earlobes, wattles, beak and nose, and comb were recorded through infrared thermography. The maximum FST (MFST) was also identified among the five face-selective regions, and its relationship with temperature-humidity index (THI) was established to identify the range of MFST in response to the variations in their thermal environment.

RESULTS

Hens exposed to OT condition at 15:00 displayed a higher temperature at wattles and around the eyes compared to other regions (p<0.001). However, under LT condition at 05:00 to 08:00, around the eyes surface temperature showed the highest value (p<0.01). In HT, wattles temperature tended to show the highest temperature over almost time intervals. Main distribution regions of MFST were wattles (63.3%) and around the eyes (16.7%) in OT, around the eyes (50%) in LT, and wattles (62.2%) and comb (18.3%) in HT. The regression equation between MFST and THI was estimated as MFST = 35.37+ 0.2383×THI (R2 = 0.44; p<0.001).

CONCLUSION

The FST and the frequency of MFST in each facial region of laying hens responded sensitively to the variations in the thermal environment. The findings of this experiment provide useful information about the effect of the thermal conditions on the specific facial regions, thus offering an opportunity to stress and welfare assessment in poultry research and industry.

Effect of L-theanine on meat quality, muscle amino acid profiles, and antioxidant status of broilers

This study investigated the effect of L-theanine on carcass traits, meat quality, muscle antioxidant capacity, and amino acid (AA) profiles of broilers. Three hundred 1-day-old Ross 308 male broilers were randomly allotted to five groups with six replicates. Birds were fed the basal diet or basal diet with 300, 600, 900, or 1,500 mg/kg L-theanine for 42 consecutive days. The results showed that L-theanine quadratically increased dressing percentage, eviscerated percentage, and leg muscle yield (p < .05). Meanwhile, drip loss, cooking loss, shear force, L*_24h, and muscle lactate content decreased quadratically in response to dietary L-theanine supplementation (p < .05), while pH_24h and muscle glycogen content were quadratically improved by L-theanine (p < .05). Notably, the contents of muscle malondialdehyde and protein carbonyl, and the activities of muscle total antioxidant capacity, catalase, and glutathione peroxidase decreased quadratically in response to dietary L-theanine supplementation (p < .05), suggesting that the oxidative stress level of muscle was decreased quadratically. Moreover, L-theanine quadratically increased the concentrations of most of muscle essential AA, nonessential AA, and flavor AA (p < .05). In conclusion, L-theanine can be used as a valuable feed additive to modulate carcass traits, meat quality, muscle antioxidant status, and AA profiles of boilers, and its optimum addition level is 600 mg/kg based on the present study.

Resveratrol improves meat quality, muscular antioxidant capacity, lipid metabolism and fiber type composition of intrauterine growth retarded pigs

This study investigated whether resveratrol could improve meat quality, muscular antioxidant capacity, lipid metabolism and fiber type composition of intrauterine growth retarded pigs. Thirty-six pairs of male normal birth weight and intrauterine growth retardation (IUGR) piglets were orally fed with 80 mg resveratrol/kg body weight/d or vehicle during the sucking period (7-21 d). Then the offspring were fed with a basal diet containing 300 mg resveratrol/kg or a basal diet from weaning to slaughter (150 d). The IUGR-impaired meat quality (luminance and yellowness) was associated with muscular oxidative stress via increased Keap1 protein level, fat accumulation, and higher MyHC IIb gene expression. Expectedly, resveratrol increased glutathione peroxidase activity and MyHC I gene expression, reduced protein carbonyl and malondialdehyde contents, enhanced fatty acid oxidation via upregulated PPARα and targeted genes expression, and thereby improving drip loss and yellowness. Results indicate that resveratrol improved meat quality of IUGR pigs through enhancing antioxidant capacity, increasing oxidative fiber composition, and suppressing lipid accumulation.

Sodium butyrate as an effective feed additive to improve performance, liver function, and meat quality in broilers under hot climatic conditions

This study was conducted to investigate the effects of dietary sodium butyrate (SB) supplementation on growth performance, liver function, antioxidant capacity, carcass characteristics, and meat quality in broilers under hot climatic conditions. A total of 288 one-day-old Arbor Acres broilers were randomly allocated to 4 dietary treatments as follow: CON, control diet without SB; T1, control diet with 300 mg/kg SB; T2, control diet with 600 mg/kg SB; and T3, control diet with 1,200 mg/kg SB. Each treatment had 6 replication pens and 12 broilers per pen. The results indicated that the BW on day 35; ADG from day 1 to 21, day 22 to 35, and day 1 to 35; and ADFI from day 22 to 35 linearly (P < 0.05) increased with SB supplementation. Interestingly, alanine aminotransferase and aspartate aminotransferase content in serum were linearly (P < 0.05) decreased by SB supplementation. There was linear (P < 0.05) improvement in activity of superoxide dismutase and catalase in the liver, whereas the content of malondialdehyde was linearly (P < 0.05) decreased with the inclusion of SB. Increasing SB level linearly (P < 0.05) increased CP composition and decreased drip loss percentage on day 1 and 3 of breast muscle. Furthermore, there was linear (P < 0.05) improvement in activity of superoxide dismutase, glutathione peroxidase, and catalase, whereas the content of malondialdehyde showed decreasing trend (P < 0.10) with the inclusion of SB in breast muscle. In conclusion, SB can be used as an effective feed additive to improve growth performance, liver function, and meat quality of broilers under hot climatic conditions.

Effects of dietary resveratrol supplementation in sows on antioxidative status, myofiber characteristic and meat quality of offspring

This study investigated the influence of dietary resveratrol (300 mg/kg) supplementation in sows on the antioxidative status, myofiber characteristic and meat quality of their progeny. Results showed that maternal dietary resveratrol supplementation increased (P < 0.05) the backfat thickness and tended (P = 0.055) to increase the intramuscular fat of finishing pigs. The drip loss and lactic acid level were reduced, and the pH_{24 h} of longissimus thoracis was increased by maternal dietary resveratrol supplementation (P < 0.05). Maternal dietary resveratrol supplementation increased the mRNA and protein expression of MyHC I and decreased the mRNA and protein expression of MyHC IIb in the longissimus thoracis (P < 0.05). The malonaldehyde (MDA) level in longissimus thoracis was reduced and the superoxide dismutase (SOD) activity and SOD2 mRNA expression were increased by maternal dietary resveratrol supplementation (P < 0.05). In conclusion, dietary resveratrol supplementation in sows improves the meat quality of offspring by altering the myofiber characteristic and antioxidative status.

Single components of botanicals and nature-identical compounds as a non-antibiotic strategy to ameliorate health status and improve performance in poultry and pigs

In the current post-antibiotic era, botanicals represent one of the most employed nutritional strategies to sustain antibiotic-free and no-antibiotic-ever production. Botanicals can be classified either as plant extracts, meaning the direct products derived by extraction from the raw plant materials (essential oils (EO) and oleoresins (OR)), or as nature-identical compounds (NIC), such as the chemically synthesised counterparts of the pure bioactive compounds of EO/OR. In the literature, differences between the use of EO/OR or NIC are often unclear, so it is difficult to attribute certain effects to specific bioactive compounds. The aim of the present review was to provide an overview of the effects exerted by botanicals on the health status and growth performance of poultry and pigs, focusing attention on those studies where only NIC were employed or those where the composition of the EO/OR was defined. In particular, phenolic compounds (apigenin, quercetin, curcumin and resveratrol), organosulfur compounds (allicin), terpenes (eugenol, thymol, carvacrol, capsaicin and artemisinin) and aldehydes (cinnamaldehyde and vanillin) were considered. These molecules have different properties such as antimicrobial (including antibacterial, antifungal, antiviral and antiprotozoal), anti-inflammatory, antioxidant, immunomodulatory, as well as the improvement of intestinal morphology and integrity of the intestinal mucosa. The use of NIC allows us to properly combine pure compounds, according to the target to achieve. Thus, they represent a promising non-antibiotic tool to allow better intestinal health and a general health status, thereby leading to improved growth performance.

Herbs as thermoregulatory agents in poultry: An overview

The adverse effect of increased environmental temperature during summer season on avian industry has received great global concern. High temperature leads to severe economic loss in poultry production, because it is considered as valuable stress factor. Several practical methods were used to alleviate the adverse impact of increased temperature; among them were dietary modifications. So, several types of herbs are supplemented to reduce the deleterious influences of thermal stress altitudes in various animals, and even to prevent their adverse impacts. Therefore, sustainable supports for dietary modification based on herbs supplementations are largely needed, particularly when consider the additional advantages of herbs such as availability, actual efficiency, low cost, as well as their free from residual impact and antibiotic resistance. Numerous types of herbs were concluded to their efficient properties by poultry breeders to overcome a variety of the harmful effects of high ambient temperature. The present article deliberates the different practical applications of several members of the traditional herbal wealth to improve the general health state of poultry particularly as thermoregulatory and immunomodulatory agents, and for countering the heat stress-associated immunosuppressive effects. Additionally, the antioxidant activity of herbal growth promoters and their influence on improvement of production performances were a special aim of this review. The reported information will be helpful for improvement of general production and health status of birds reared under the heat stress via enhancement of immune response and stress tolerance, and popularizes usage of herbs amongst poultry producers.

Glutamine improves heat stress-induced oxidative damage in the broiler thigh muscle by activating the nuclear factor erythroid 2-related 2/Kelch-like ECH-associated protein 1 signaling pathway

The aim of the present study was to evaluate the effect of glutamine (Gln) on modulating heat stress–induced oxidative damage in the broiler thigh muscle through nuclear factor erythroid 2–related 2/Kelch-like ECH-associated protein 1 (Nrf2-Keap1) pathway. Three-hundred 22-day-old Arbor Acres broilers were reallocated into 5 groups: a control group (24 °C) fed with basal diet and 4 heat stress (HS) groups (34 °C for 8 h/D) fed with basal diet containing 0, 0.5, 1.0, and 1.5% Gln. This experiment lasted 21 D. Heat stress decreased (P < 0.05) pH, redness, and Gln levels, and increased (P < 0.05) luminance, water loss rate, and cooking loss (CL) values of the thigh meat. Compared with the HS group, supplementation with 1.5% Gln increased (P < 0.05) pH, redness, and Gln levels, but decreased (P < 0.05) luminance and CL values in the thigh meat. There were significant decreases (P < 0.05) in glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and Nrf2 levels, but significant increases (P < 0.05) in the malondialdehyde (MDA) and Keap1 levels of the thigh muscle after HS treatment. Compared with the HS group, supplementation with 1.0, and 1.5% Gln decreased (P < 0.05) MDA and Keap1 levels; supplementation with 1.5% Gln increased (P < 0.05) GSH, GSH-Px, T-AOC, CAT, SOD, and Nrf2 levels in the thigh muscle of heat-stressed broilers. Furthermore, HS decreased (P < 0.05) Nrf2, SOD, CAT, and GSH-Px mRNA expression levels, but increased (P < 0.05) Keap1 mRNA level in the thigh muscle of broiler. Dietary supplementation with 1.5% Gln increased (P < 0.05) Nrf2, GSH-Px, CAT, and SOD mRNA expression levels, but decreased (P < 0.05) Keap1 mRNA level in the thigh muscle of heat-stressed broilers. In conclusion, dietary Gln improved the resistance of heat-stressed broiler muscles to oxidative damage possibly through reversing the muscle Gln level and inducing the expression of the Nrf2-Keap1 pathway.

Effects of resveratrol on intestinal oxidative status and inflammation in heat-stressed rats

Heat stress, experienced by humans and animals under high ambient temperatures, is known to induce oxidative stress and inflammation, which endangers human health as well as animal welfare and production. The gastrointestinal tract is predominantly responsive to heat stress and compromised intestinal functions can contribute to multi-organ injury under heat environment. Resveratrol (RSV) has significant antioxidant and anti-inflammatory activities. The aim of this study was to investigate the potential effects of RSV on intestinal function (digestion and barrier), oxidative stress and inflammation in heat-stressed rats. Male Sprague-Dawley rats were orally fed with 100 mg RSV/kg body weight/day prior to daily heat stress (40 °C per day for 1.5 h) exposure for 3 consecutive days. The results showed that RSV reversed the increased serum cortisol level and diamine oxidase activity, the altered jejunal morphology, the decreased jejunal disaccharidase activities, the elevated malondialdehyde and tumor necrosis factor alpha concentrations and antioxidant enzymes activities in the jejunum, as well as the increased jejunal mRNA expression of toll-like receptor 4, cytokines, antioxidant enzymes and tight junction proteins in heat-stressed rats, to various degrees. In conclusion, RSV could alleviate intestinal injury and dysfunctions by improving oxidative status and suppressing inflammation in heat-stressed rats.

Protective effect of resveratrol against hepatic damage induced by heat stress in a rat model is associated with the regulation of oxidative stress and inflammation

Heat stress jeopardizes humans and animals health, and results in enormous economic loss in public health care and livestock production. The aim of this study was to investigate the effects of resveratrol on hepatic oxidative stress and inflammation in heat-stressed rats. Male Sprague-Dawley rats were orally fed with 100 mg resveratrol/kg body weight/day prior to heat stress (40 ∘C per day for 1.5 h) exposure for 3 consecutive days. Serum and liver samples were collected for the analysis of hepatic injury, redox status and immune response. The results showed that the heat-stress-induced increased aspartate aminotransferase activities in the serum, aberrant hepatic histology, excessive hepatic malondialdehyde and tumor necrosis factor alpha concentrations, and up-regulation of heat shock protein 70, superoxide dismutase 1, glutathione peroxidase 1, toll-like receptor 4 and interleukin 10 mRNA expression in the liver were mitigated by oral resveratrol treatment. Collectively, the beneficial effects of resveratrol on hepatic damage induced by heat stress were associated with the regulation of oxidative stress and inflammation.

Polyphenols as Potential Attenuators of Heat Stress in Poultry Production

Heat stress is a non-specific physiological response of the body when exposed to high ambient temperatures, which can break the balance of body redox and result in oxidative stress that affects growth performance as well as the health of poultry species. Polyphenols have attracted much attention in recent years due to their antioxidant ability and thus, can be an effective attenuator of heat stress. In this paper, the potential mechanisms underlying the inhibitory effect of polyphenols on heat stress in poultry has been reviewed to provide a reference and ideas for future studies related to polyphenols and poultry production.

Stress Effects on Meat Quality: A Mechanistic Perspective

Stress inevitably occurs from the farm to abattoir in modern livestock husbandry. The effects of stress on the behavioral and physiological status and ultimate meat quality have been well documented. However, reports on the mechanism of stress effects on physiological and biochemical changes and their consequent effects on meat quality attributes have been somewhat disjointed and limited. Furthermore, the causes of variability in meat quality traits among different animal species, muscle fibers within an animal, and even positions within a piece of meat in response to stress are still not entirely clear. This review 1st summarizes the primary stress factors, including heat stress, preslaughter handling stress, oxidative stress, and other stress factors affecting animal welfare; carcass quality; and eating quality. This review further delineates potential stress-induced pathways or mediators, including AMP-activated protein kinase-mediated energy metabolism, crosstalk among calcium signaling pathways and reactive oxygen species, protein modification, apoptosis, calpain and cathepsin proteolytic systems, and heat shock proteins that exert effects that cause biochemical changes during the early postmortem period and affect the subsequent meat quality. To obtain meat of high quality, further studies are needed to unravel the intricate mechanisms involving the aforementioned signaling pathways or mediators and their crosstalk.

Protective effects of resveratrol against high ambient temperature-induced spleen dysplasia in broilers through modulating splenic redox status and apoptosis

BACKGROUND

Resveratrol has been shown to prevent high ambient temperature (HT)-induced spleen dysplasia, but the mechanisms of action are not clear. This study aims to examine the hypothesis that HT-induced spleen dysplasia may be associated with HT-induced oxidative stress and apoptosis, and resveratrol may activate the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, thus reducing oxidative stress and apoptosis.

RESULTS

Results showed that HT caused spleen dysplasia in broilers, reflecting the lower relative weight of the spleen (P < 0.05). Compared with birds in a normal ambient temperature group, birds in the HT group exhibited higher (P < 0.05) malondialdehyde (MDA), protein carbonyl (PC), 8-hydroxydeoxyguanosine (8-OHdG) and Bcl-2 associated X protein (Bax) content, higher Bax, caspase-3 and caspase-9 mRNA levels, and caspase-3 and caspase-9 activity, and a higher Bax/B-cell lympoma/leukemia-2 (Bcl-2) ratio, but they exhibited lower (P < 0.05) glutathione (GSH) and Bcl-2 content, and lower Nrf2, glutathione peroxidase (Gpx), MnSOD, heme oxygenase 1, glutathione reductase (GR) and Bcl-2 mRNA levels, and lower total antioxidant capacity (T-AOC), T-SOD and catalase and maganese superoixide dismutase (CAT) activity, indicating HT-induced oxidative stress and apoptosis. Compared with birds in the HT group, birds in the HT + Res group exhibited higher (P < 0.05) GSH and Bcl-2 content, higher Nrf2, CAT, MnSOD, GR and Bcl-2 mRNA levels, and higher T-AOC, T-SOD and CAT activity, but lower (P < 0.05) MDA content, and Bax and caspase-3 mRNA levels, lower caspase-3 and caspase-9 activities, and Bax/Bcl-2 ratio, indicating that resveratrol activated the Nrf2 signaling pathway and decreased apoptosis in the spleen.

CONCLUSION

Resveratrol was effective in ameliorating HT-induced spleen dysplasia in broilers through the activation of the Nrf2 signaling pathway, thereby decreasing apoptosis, suggesting that resveratrol may offer a potential nutritional strategy to protect against some HT-induced detriments. © 2018 Society of Chemical Industry.

Effect of l-theanine on the growth performance, immune function, and jejunum morphology and antioxidant status of ducks

l-theanine is a unique nonproteinogenic amino acid found in tea, and has recently received considerable attention because of its various biological activities. However, there is no available research report on the use of l-theanine as a feed additive in ducks. This study was conducted to investigate the potential benefits and appropriate dosages of l-theanine on the growth performance, immune function, serum biochemical parameters, and jejunum morphology and antioxidant capacity of ducks. A total of 600 1-day-old Chaohu ducks were randomly allocated into five dietary treatment groups supplemented with 0 (control group), 300, 600, 900 and 1500 mg/kg of l-theanine. Each group included five replicates of 24 birds each. Body weight at day 28 was increased (P&lt;0.05) by l-theanine. From days 15 to 28, l-theanine elevated cumulative BW gain (BWG) and cumulative feed intake (FI), and decreased feed to gain ratio. From days 1 to 28, l-theanine elevated (P&lt;0.05) cumulative BWG and cumulative FI. l-theanine elevated (P&lt;0.05) the relative weight of bursa of Fabricus (day 14), thymus (day 14), spleen (day 28) and liver (day 28). On day 28, l-theanine decreased (P&lt;0.05) serum glucose, uric acid, triacylglycerol, total cholesterol, low-density lipoprotein cholesterol, insulin, interleukin-2 (IL-2) and IL-6 contents, and elevated (P&lt;0.05) serum total protein, globulin (GLB), immune globulin A (IgA) and IgG contents, but only serum insulin, interferon-γ, tumor necrosis factor-α and IL-6 contents was decreased (P&lt;0.05) and serum GLB and IgM content was elevated (P&lt;0.05) by l-theanine on day 14. On day 14, l-theanine decreased (P&lt;0.05) jejunum crypt depth, and elevated (P&lt;0.05) jejunum villus height, villus height to crypt depth ratio (V/C), goblet cell number and total superoxide dismutase (T-SOD) activity. On day 28, l-theanine decreased (P&lt;0.05) jejunum malondialdehyde content, and elevated (P&lt;0.05) jejunum villus height, V/C, goblet cell number, and T-SOD, catalase and glutathione peroxidase activities. l-theanine levels caused quadratic effect on the growth performance, relative organ weight, serum parameters, jejunum morphology and antioxidant capacity. In conclusion, l-theanine can be used as a promising feed additive for ducks, and its optimal supplementation level was 600 to 900 mg/kg based on the current experimental condition.

Rabbit metabolic response and selected meat quality traits: Evaluation of dietary PLX® 23 and LycoBeads® feed supplement

Effects of dietary supplementation of verbascoside and lycopene, alone and in combination, on some blood parameters, plasma oxidative status and meat quality traits in intensively reared rabbits were investigated. The test lasted 60 days and was conducted on 200 weaned-rabbits, divided into four groups of 50 animals each (5 animals each cage × 10 repetitions). The control group (CON) received a fattening feed without any feed supplements, whereas the experimental groups received the following: the first, an integration in 22 g of PLX^® 23 (Lippia citriodora extract; VB group) per ton of feed; the second, an integration in 100 g of LycoBeads^® (Solanum lycopersicum extract; LIC group) per ton of feed; and the third, an integration of both feed supplements in combination at the same doses (LIC+VB group). The dietary supplementation with Lippia citriodora and Solanum lycopersicum resulted in an improvement of the blood lipid profile, oxidative plasma markers, and hepatic and renal activity of treated growing rabbits. Feed additives also produced meat with a lower content in SFA and an increased PUFA content, and inhibited the lipid oxidation improving the oxidative stability of rabbit meat. The dietary supplementation, even reporting no effects on productive parameters and carcass yield, showed an improvement on several blood parameters, as indicator of animal welfare, and on quality and healthy meat markers.

Effects of different rearing systems on growth performance, carcass traits, meat quality and serum biochemical parameters of Chaohu ducks

This study was conducted using a total of 360 22-day-old Chaohu ducks to evaluate the effect of rearing system on growth performance, carcass traits, meat quality and serum parameters of male and female Chaohu ducks. The birds were divided and raised in separate pens according to sex and rearing system, with three replicate pens of 30 male or 30 female ducks per pen for each rearing system. The rearing systems consisted of a floor rearing system (FRS) and a net rearing system (NRS). Results showed that ducks raised in NRS had better growth performance, whereas, ducks raised in FRS exhibited better carcass traits and meat color, and lower intramuscular fat. For the serum parameters, NRS significantly decreased high-density lipoprotein cholesterol content, and enhanced total protein and triacylglycerol contents. Male ducks had lower abdominal fat percentage, and higher growth performance and shear force, but there were no other significant differences between sexes. No rearing system × sex interaction was observed in the present study, revealing that rearing system had the same effect on both sexes. In conclusion, NRS was beneficial to the growth performance of Chaohu ducks, whereas this system had some negative effects on carcass traits, meat quality and serum profiles.