Dietary Manipulation Research Articles

Recent Advances in Enteric Methane Mitigation and the Long Road to Sustainable Ruminant Production.

Mitigation of methane emission, a potent greenhouse gas, is a worldwide priority to limit global warming. A substantial part of anthropogenic methane is emitted by the livestock sector, as methane is a normal product of ruminant digestion. We present the latest developments and challenges ahead of the main efficient mitigation strategies of enteric methane production in ruminants. Numerous mitigation strategies have been developed in the last decades, from dietary manipulation and breeding to targeting of methanogens, the microbes that produce methane. The most recent advances focus on specific inhibition of key enzymes involved in methanogenesis. But these inhibitors, although efficient, are not affordable and not adapted to the extensive farming systems prevalent in low- and middle-income countries. Effective global mitigation of methane emissions from livestock should be based not only on scientific progress but also on the feasibility and accessibility of mitigation strategies.

Randomised controlled trial of the effects of kefir on behaviour, sleep and the microbiome in children with ADHD: a study protocol

IntroductionCurrent interventions for children with attention-deficit/hyperactivity disorder (ADHD) are primarily medication, behavioural therapy and parent training. However, research suggests dietary manipulations may provide therapeutic benefit for some. There is accumulating...

Gut Microbiota and Obesity: The Chicken or the Egg?

Although the link between gut microbiota and obesity is increasingly reported, the pathophysiological mechanisms and clinical outcomes are still under debate. This overview of human and animal data addresses several pathophysiologic mechanisms, dietary habits, exercise and probiotic and symbiotic supplementation in the fields of gut microbiota and obesity. Overall, obesity impairs gut microbiota composition due to factors that may be linked to the onset of the disease, such as excessive consumption of high-energy foods, sugars and fats, as well as a low fiber intake and physical inactivity. Conversely, low-energy diets, physical exercise, and probiotic and prebiotic supplementations can enhance gut microbiota in patients with obesity, in addition to improving cardiometabolic markers. As for perspectives, further research is warranted to ascertain proper dietary manipulation, physical exercise protocols and dosing regimens of probiotics. Regarding the latter, the effects on indicators of obesity are clinically modest, and hence skepticism must be exercised.

Major clinical evidence of calorie restriction and intermittent fasting on skin health: a systematic review

Introduction: Combined skin diseases represent the fourth leading cause of non-fatal disability worldwide. In 2013, it was estimated that skin diseases represented almost 2.0% of the total global burden of disease. Different fasting models have been studied in an attempt to understand the effect of fasting on skin structure and function. Objective: It was to present the main scientific evidence of the effects of calorie restrictions and intermittent fasting on skin health. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from July to September 2023 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 119 articles were found, and 26 articles were evaluated in full, and 23 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 22 studies with a high risk of bias and 26 studies that did not meet GRADE and AMSTAR-2. Most studies showed homogeneity in their results, with X2=64.7%>50%. It was concluded that although calorie restriction is the most effective intervention to prolong the life of organisms and prevent age-related diseases, its effects on aging and skin diseases can be significant. Dietary lifestyles can affect epithelial lineages such as the skin and intestine. The impact of Ramadan fasting on skin health can be compared with the effect of other types of fasting, including periodic dieting, calorie restriction, dietary restriction, dietary manipulation, and intermittent, short-term, and prolonged fasting. However, despite the scarcity of studies on the topic, no serious health risks have been reported and, therefore, patients who wish to fast should be warned about the importance of continuing their treatment and the administration of transdermal/topical medications.

103 Development of a Novel, Experimental, Minimally Invasive Model to Investigate the Genesis and Etiology of Liver Abscesses in Cattle

Abstract Most research surrounding liver abscesses involves post-hoc evaluation of naturally occurring abscesses in production settings. Few studies have been designed to experimentally induce abscesses with the purpose of identifying a time course, causality, and associated physiological implications. Therefore, we set out to develop a minimally invasive, reliable, and repeatable model to induce liver abscesses in calves in a controlled research environment to elucidate the genesis and etiology of the disease, with the ultimate goal of developing abscess reduction strategies. Experiment 1 was an attempt to induce abscesses by intraruminal inoculation with Fusobacterium necrophorum, Salmonella lubbock, and Truperella pyogenes (FST) following an intravenous lipopolysaccharide challenge. Holstein steers were harvested 3- and 10-d after inoculation, but no abscesses were detected. Experiments 2 and 3 involved diet manipulation by cycling calves on and off a high-starch, acidotic diet followed by intraruminal inoculation of microbes. In Experiment 2, Holstein calves were fed a negative control diet, an acidotic diet, and an acidotic diet plus bacterial inoculation with FST. No abscesses formed in the control or acidotic diet calves, but 43% of calves fed the acidotic diet with FST inoculation formed liver abscesses, suggesting that acidosis alone is insufficient to produce abscesses. In Experiment 3, treatments consisted of Holstein steers fed a negative control, an acidotic diet, an acidotic diet plus ruminal Fusobacterium necrophorum (F), and an acidotic diet plus Fusobacterium and Salmonella (FS). Again, there were no abscesses in the control or calves fed an acidotic diet alone; however, 40% of calves receiving F presented with an abscess, and 50% of the calves that received FS presented with abscesses. These data suggest that ruminal acidosis in conjunction with a ruminal load of pathogens commonly associated with liver abscesses provides a model that will induce liver abscesses. While the role of barrier dysfunction in the rumen and the lower gastrointestinal tract in formation of abscesses is not fully understood, this work provides a foundation to further explore the etiology of this disease and potential mitigation strategies.

Food and mood: healthy eating for mental health with chronic kidney disease

There is a growing interest in the connection between healthy eating, mental health (MH) and chronic disease prevention. Although people with chronic kidney disease (CKD) are disproportionately affected by poor MH, nutritional guidelines have traditionally focused on non-mental factors, such as physical health, disease progression and biochemical control. Dietary manipulation, through healthy eating, may influence the gut microbiome, as well as mental and kidney health. This can be achieved through the interaction between the gut microbiome, brain and kidney, as well as the body's metabolism of nutrients, such as the amino acid tryptophan. While a wide range of nutrients are implicated in brain function and health, there is little evidence to support supplementation-based treatments–other than to avoid conventional malnutrition and micronutrient deficiencies. Whole diets, such as the Mediterranean diet, may benefit MH, as well as reducing cardiovascular, renal and other chronic disease risk. A supportive and individualised approach to renal dietary restrictions may help to reduce the MH burden of CKD.

312 Evaluation of Dietary Roughage Manipulation During the Feeding of Ractopamine Hydrochloride as a Method to Improve Ruminal Health and Control Liver Abscess Severity in Feedlot Steers

Abstract The objective of this study was to determine if additional roughage inclusion to feedlot steer finishing diets during the feeding of ractopamine hydrochloride (RH) is an effective method to improve rumen health and control liver abscess severity. Steers [n = 64; initial shrunk body weight (SBW) = 633 kg ± 35.1 kg] were sourced from an unrelated trial and remained in their previous study pens; pens (n = 8) were assigned to dietary treatment in a completely randomized design. All steers on trial were fed a common 7% [dry matter (DM) basis] roughage equivalent (RE) finishing diet composed of dry-rolled corn, dried distillers grains plus solubles, corn silage, and grass hay for the 58 d preceding study initiation. Steers were fitted with rumination tags to track daily rumination. Dietary treatments were CON: no diet change; and 12R: 5% (DM basis) RE addition to diet via grass hay during the feeding of RH. Steers were fed RH (300 mg/steer/d), finished on treatment diets for 28 d, and harvested at a commercial beef processor. Growth performance, efficiency of dietary net energy (NE) utilization, and continuous carcass data were analyzed with pen as the experimental unit (EU) and fixed effect of treatment. Minutes ruminating was analyzed as an analysis of covariance with individual animal as the EU, fixed effects of treatment, days on feed (DOF) and their interaction, and baseline minutes ruminating as a covariate in the model. Liver abscess prevalence, rumen health, and categorical carcass data were analyzed with the Fisher’s exact test to determine differences between treatments. No difference (P ≥ 0.19) was observed for final SBW, average daily gain, dry matter intake, feed conversion efficiency, dressing percentage, hot carcass weight, calculated yield grade, marbling score, 12th rib fat thickness, calculated empty body fat, observed dietary NE for maintenance and gain, observed-to-expected dietary NE for maintenance and gain, or distribution of liver abscess prevalence, ruminitis score, or USDA yield grade. Ribeye area tended (P = 0.10) to differ between treatments with 12R steers exhibiting a 3.5% larger ribeye. Distribution of USDA quality grade differed (P = 0.003) between treatments with 12R steers having 25% more carcasses grading USDA average choice or better. A treatment × DOF interaction (P = 0.045) was observed for minutes ruminating per day. Daily minutes ruminating was increased (P ≤ 0.05) for 12R on d 1, 2, and 20 and tended to be increased (P ≤ 0.10) for 12R on days 10, 13, 24, and 25. Inclusion of an additional 5% RE to finishing cattle diets during a 28 d RH feeding period can be a management strategy to decrease risk of digestive upsets without sacrificing growth performance or carcass quality.

91 Methanogen Ecology in the Ruminant Hindgut

Abstract Environmental methane production continues to be an ongoing global concern and interest is growing to reduce total methane production. As a part of this collective effort mitigation of methane production in ruminants has become one of the targets for ongoing research. Several strategies have emerged including dietary manipulation, administration of unique feed additives that specifically target methanogens, and host animal modulation approaches. Most of these efforts have focused on the rumen methanogen population and understanding their ecology in relationship to the non-methanogen microbial population. However, there is potential for methane production in the hindgut of the ruminant animal, and this should be considered in any overall strategy for mitigation of methane production in ruminants. The emphasis of this presentation is to discuss the current knowledge and future prospects for understanding the contribution of hindgut methanogens to overall ruminant methane production and their potential for contribution to mitigation of ruminant methane production.

Effects of junk-food on food-motivated behavior and nucleus accumbens glutamate plasticity; insights into the mechanism of calcium-permeable AMPA receptor recruitment

In rats, eating obesogenic diets increases calcium-permeable AMPA receptor (CP-AMPAR) transmission in the nucleus accumbens (NAc) core, and enhances food-motivated behavior. Interestingly, these diet-induced alterations in NAc transmission are pronounced and sustained in obesity-prone (OP) male rats and absent in obesity-resistant (OR) populations. However, effects of diet manipulation on food motivation, and the mechanisms underlying this NAc plasticity in OPs is unknown. Using male selectively-bred OP and OR rats, we assessed food-motivated behavior following ad lib access to chow (CH), junk-food (JF), or 10d of JF followed by a return to chow diet (JF-Dep). Motivation for food was greater in OP than OR rats, as expected. However, JF-Dep only produced enhancements in food-seeking in OP groups, while continuous JF access reduced food-seeking in both OPs and ORs. Additionally, optogenetic, chemogenetic, and pharmacological approaches were used to examine NAc CP-AMPAR recruitment following diet manipulation and ex vivo treatment of brain slices. Reducing excitatory transmission in the NAc was sufficient to recruit CP-AMPARs to synapses in OPs, but not ORs. In OPs, JF-induced increases in CP-AMPARs occurred in mPFC-, but not BLA-to-NAc inputs. Together results show that diet differentially affects behavioral and neural plasticity in obesity susceptible populations. We also identify conditions for acute recruitment of NAc CP-AMPARs; these results suggest that synaptic scaling mechanisms contribute to NAc CP-AMPAR recruitment. Overall, this work helps elucidate how diet interacts with obesity susceptibility to influence food-motivated behavior and extends our fundamental understanding of NAc CP-AMPAR recruitment.

Dietary fatty acids improve perceived sleep quality, stress, and health in migraine: a secondary analysis of a randomized controlled trial.

Migraine is a prevalent disabling condition often associated with comorbid physical and psychological symptoms that contribute to impaired quality of life and disability. Studies suggest that increasing dietary omega-3 fatty acid is associated with headache reduction, but less is known about the effects on quality of life in migraine. After a 4-week run-in, 182 adults with 5-20 migraine days per month were randomized to one of the 3 arms for sixteen weeks. Dietary arms included: H3L6 (a high omega-3, low omega-6 diet), H3 (a high omega-3, an average omega-6 diet), or a control diet (average intakes of omega-3 and omega-6 fatty acids). Prespecified secondary endpoints included daily diary measures (stress perception, sleep quality, and perceived health), Patient-Reported Outcome Measurement Information System Version 1.0 ([PROMIS©) measures and the Migraine Disability Assessment (MIDAS). Analyses used linear mixed effects models to control for repeated measures. The H3L6 diet was associated with significant improvements in stress perception [adjusted mean difference (aMD): -1.5 (95% confidence interval: -1.7 to -1.2)], sleep quality [aMD: 0.2 (95% CI:0.1-0.2)], and perceived health [aMD: 0.2 (0.2-0.3)] compared to the control. Similarly, the H3 diet was associated with significant improvements in stress perception [aMD: -0.8 (-1.1 to -0.5)], sleep quality [aMD: 0.2 (0.1, 0.3)], and perceived health [aMD: 0.3 (0.2, 0.3)] compared to the control. MIDAS scores improved substantially in the intervention groups compared with the control (H3L6 aMD: -11.8 [-25.1, 1.5] and H3 aMD: -10.7 [-24.0, 2.7]). Among the PROMIS-29 assessments, the biggest impact was on pain interference [H3L6 MD: -1.8 (-4.4, 0.7) and H3 aMD: -3.2 (-5.9, -0.5)] and pain intensity [H3L6 MD: -0.6 (-1.3, 0.1) and H3 aMD: -0.6 (-1.4, 0.1)]. The diary measures, with their increased power, supported our hypothesis that symptoms associated with migraine attacks could be responsive to specific dietary fatty acid manipulations. Changes in the PROMIS© measures reflected improvements in non-headache pain as well as physical and psychological function, largely in the expected directions. These findings suggest that increasing omega-3 with or without decreasing omega-6 in the diet may represent a reasonable adjunctive approach to reducing symptoms associated with migraine attacks. Trial Registration: ClinicalTrials.gov NCT02012790.

Optimization of Brewer's Yeast Quantity in Liquid and Gel Larval Diets for the Mediterranean Fruit Fly.

Several artificial larval diets have been developed, evaluated and used for mass-rearing of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Teprhitidae). There are several efforts to reduce the cost of rearing and optimize the quality of the produced sterile males that are destined for release in sterile insect release programs. Survival, growth, longevity and reproductive capacity of sterile males are strongly connected with the most expensive ingredient, the brewer's yeast (protein), in the larval diet. The current study focused on settling the optimal content of brewer's yeast in a liquid diet and a gel diet. Egg hatch rates, developmental duration of immatures, pupation rate, pupae and adult survival were recorded as indicators of quantity and quality of the produced adults. Egg hatch was higher and larval developmental duration longer in the gel diet. In contrast to the liquid diet, an increase in brewer's yeast concentration was correlated with increased pupation rate and pupae survival in the gel diet. Reducing brewer's yeast up to 50% of its initial quantity had no significant effect on the survival of the emerging adults regardless of the diet type. Our findings may contribute to the production of low-cost and effective diets for use in mass-rearing facilities of medflies.

The impact of diet on sperm length in the long‐tailed finch (Poephila acuticauda)

Sperm traits are important in determining fertilisation success and are metabolically expensive to produce. There is little known about how energy acquisition and allocation affect sperm traits in avian taxa. This study assesses the impact of experimentally manipulated diet on long‐tailed finch sperm by comparing the length of sperm components (head, midpiece, flagellum and total sperm) between the treatment groups (homogenous diet and diverse diet) and across time points (before and after the experiment). Diet homogeneity was manipulated as this may impact diet quality in a species that is usually fed a diversity of seed species to thrive in captivity. Our results showed no impact of diet on the length of different sperm components. These results contrast with findings of a similar recent study of the zebra finch which found a significant level of diet‐affected plasticity in midpiece length. For both diet treatment groups in this study there was a slight but significant increase in head, flagellum and total sperm length over the treatment period. Despite this, all sperm components were highly repeatable, consistent with the finding from observational studies in passerine birds. The efficacy of our dietary manipulation was confirmed by a significant reduction in the saturation of bill colour in the long‐tailed finches as a result of the homogenous diet, and a difference in body mass across the treatment groups.

Dietary supplementation of cystinotic mice by lysine inhibits the megalin pathway and decreases kidney cystine content

Megalin/LRP2 is a major receptor supporting apical endocytosis in kidney proximal tubular cells. We have previously reported that kidney-specific perinatal ablation of the megalin gene in cystinotic mice, a model of nephropathic cystinosis, essentially blocks renal cystine accumulation and partially preserves kidney tissue integrity. Here, we examined whether inhibition of the megalin pathway in adult cystinotic mice by dietary supplementation (5x-fold vs control regular diet) with the dibasic amino-acids (dAAs), lysine or arginine, both of which are used to treat patients with other rare metabolic disorders, could also decrease renal cystine accumulation and protect cystinotic kidneys. Using surface plasmon resonance, we first showed that both dAAs compete for protein ligand binding to immobilized megalin in a concentration-dependent manner, with identical inhibition curves by l- and d-stereoisomers. In cystinotic mice, 2-month diets with 5x-l-lysine and 5x-l-arginine were overall well tolerated, while 5x-d-lysine induced strong polyuria but no weight loss. All diets induced a marked increase of dAA urinary excretion, most prominent under 5x-d-lysine, without sign of kidney insufficiency. Renal cystine accumulation was slowed down approx. twofold by L-dAAs, and totally suppressed by d-lysine. We conclude that prolonged dietary manipulation of the megalin pathway in kidneys is feasible, tolerable and can be effective in vivo.

Does altering your diet reduce your risk of depression and are any dietary manipulations an effective treatment for depression?

One of the areas of greatest public interest is whether altering your diet can reduce your risk of developing depression and whether there are any dietary manipulations that are effective treatments for depression? Many epidemiological studies have suggested associations between lower rates of depression and specific dietary types (e.g., Mediterranean, ‘anti-inflammatory’, Keto, low carbohydrate and Fish oil-rich) (Dietch et al., 2023). These epidemiological data are buttressed by post hoc analyses of several large-scale clinical trials with other primary outcomes – the PREDIMED study being an exemplar (Sánchez et al., 2013). In addition, the first generation of randomised controlled trials is now available suggesting that a healthier diet pattern especially the Mediterranean diet reduces the symptoms of depression in clinical populations (Jacka et al., 2017).

Postprandial metabolism of Australian hybrid abalone (Haliotis laevigata × H. rubra) in relation to temperature and dietary protein manipulation

Understanding the physiological responses of abalone to culture conditions and nutritional inputs is paramount to maintain optimal performance under densely stocked farming conditions. High water temperature (>24 °C) is widely accepted as a key contributor to elevated summer mortality. High crude protein levels in modern abalone diets may interact with elevated water temperature to produce detrimental effects on abalone physiological processes but have received scant attention. This study measured the energy used in the digestion, absorption, and assimilation (i.e., specific dynamic action (SDA)) of hybrid abalone (Haliotis laevigata x H. rubra) after four months of acclimation to three protein levels (32, 38 and 44%) at three culture temperatures (12, 17 and 22 °C). Hybrid abalone exhibited significant stepwise increases in meal size as temperature increased from 12 through to 22 °C, contributing to significantly different SDA between the temperature treatments. Resting (standard) aerobic metabolic rate and peak metabolism (peak ṀO2) during SDA both increased with temperature, while SDA duration was lowest at 17 °C. No effect of dietary protein was observed within the temperature treatments for the SDA metrics. Abalone held at 12 °C exhibited significantly higher rates of gonad maturation, particularly among females. When 22 °C-acclimated abalone were exposed to a simulated summer heatwave up to 26 °C, they exhibited similar mortality and metabolic responses across protein treatment groups and there was a trend of steadily decreasing ṀO2 with sustained 26 °C water temperature, probably due to fasting. These results help to inform best farming practices to ensure optimal diet, growth, metabolic performance, and survival of hybrid abalone in the dynamic farm environment.

Nutritional Considerations for Bladder Storage Conditions in Adult Females.

Clinical guidelines developed by urologic, urogynecologic, and gynecologic associations around the globe include recommendations on nutrition-related lifestyle and behavioral change for bladder storage conditions. This study identified and compared clinical guidelines on three urological conditions (interstitial cystitis/bladder pain syndrome (IC/BPS), overactive bladder, and stress urinary incontinence) affecting adult women. A three-step process was employed to identify the guidelines. Next, a quality assessment of the guidelines was conducted employing the Appraisal of Guidelines Research and Evaluation (AGREE II) International tool. (3) Results: Twenty-two clinical guidelines, prepared by seventeen groups spanning four continents, met the inclusion criteria. The AGREE II analyses revealed that most of the guideline development processes complied with best practices. The most extensive nutrition recommendations were for women with IC/BPS. Dietary manipulation for the other two storage LUTS primarily focused on the restriction or limitation of specific beverages and/or optimal fluid intake. (4) Conclusion: Clinical guidelines for IC/BPS, overactive bladder, and stress urinary incontinence include nutrition recommendations; however, the extent of dietary manipulation varied by condition. The need to ensure that clinicians are informing patients of the limitations of the evidence supporting those recommendations emerged. Furthermore, given the need to treat nutrition-related comorbid conditions as a strategy to help mitigate these three urological disorders, the value of referral to a dietitian for medical nutrition therapy is apparent.

Mechanisms of improved body composition among perimenopausal women practicing Meditative Movement: a proposed biobehavioral model.

Weight gain and unfavorable body composition are prevalent among midlife/older women throughout menopause. These shifts may negatively impact health, well-being, and longevity. Efforts to attenuate weight and body composition changes are traditionally driven by manipulation of diet and/or exercise; however, sustained results are limited, possibly because the full spectrum of biobehavioral systems is not addressed by diet and exercise alone. We propose a biobehavioral model detailing mechanisms of body composition decline among perimenopausal women and the associated components of Meditative Movement (ie, tai chi, qigong, yoga) that address each of these factors. Based on our previous work and extensive review of the literature, we developed a multifactorial and multidimensional biobehavioral model including factors that most directly relate to body composition among perimenopausal women: 1) psychological (ie, stress and mood, mindfulness and self-compassion, body awareness), 2) behavioral (ie, sleep, physical activity, eating behaviors), and 3) physiological (ie, cortisol, estrogen). Relationships between each factor, Meditative Movement practice components, and predicted effects on body composition were explored in detail. Our model describes select psychological, behavioral, and physiological factors, and potential mechanistic pathways of Meditative Movement practice driving improved changes in body composition and weight outcomes for perimenopausal women. The proposed model details a novel, evidence-supported means to reduce the risk of deleterious shifts in body composition throughout perimenopause and menopause thereafter. We suggest that these changes may occur directly and/or indirectly through psychological, behavioral, and physiological mechanisms that facilitate the desired changes in body composition.

The onset of adenosine monophosphate-activated protein kinase activity on orthodontic tooth movement in rats with type 2 diabetes.

Adenosine monophosphate-activated protein kinase (AMPK) plays pivotal roles in metabolic diseases including type 2 diabetes. However, the specific role of AMPK for orthodontic tooth movement in type 2 diabetes is unclear. In this study, a diabetic rat model was established through dietary manipulation and streptozocin injection. Examinations were conducted to select qualified type 2 diabetic rats. Then, an orthodontic device was applied to these rats for 0, 3, 7, or 14 days. The distance of orthodontic tooth movement and parameters of alveolar bone were analyzed by micro-computed tomography. Periodontal osteoclastic activity, inflammatory status, and AMPK activity were measured via histological analyses. Next, we repeated the establishment of diabetic rats to investigate whether change of AMPK activity was associated with orthodontic tooth movement under type 2 diabetes. The results showed that diabetic rats exhibited an exacerbated alveolar bone resorption, overactive inflammation, and decreased periodontal AMPK activity during orthodontic tooth movement. Injection of the AMPK agonist alleviated type 2 diabetes-induced periodontal inflammation and alveolar bone resorption, thus normalizing distance of orthodontic tooth movement. Our study indicates that type 2 diabetes decreases periodontal AMPK activity, leading to excessive inflammation elevating osteoclast formation and alveolar bone resorption, which could be reversed by AMPK activation.

Alleviating heat stress effects in poultry: updates on methods and mechanisms of actions.

Heat stress is a threat that can lead to significant financial losses in the production of poultry in the world's tropical and arid regions. The degree of heat stress (mild, moderate, severe) experienced by poultry depends mainly on thermal radiation, humidity, the animal's thermoregulatory ability, metabolic rate, age, intensity, and duration of the heat stress. Contemporary commercial broiler chickens have a rapid metabolism, which makes them produce higher heat and be prone to heat stress. The negative effect of heat stress on poultry birds' physiology, health, production, welfare, and behaviors are reviewed in detail in this work. The appropriate mitigation strategies for heat stress in poultry are equally explored in this review. Interestingly, each of these strategies finds its applicability at different stages of a poultry's lifecycle. For instance, gene mapping prior to breeding and genetic selection during breeding are promising tools for developing heat-resistant breeds. Thermal conditioning during embryonic development or early life enhances the ability of birds to tolerate heat during their adult life. Nutritional management such as dietary manipulations, nighttime feeding, and wet feeding often, applied with timely and effective correction of environmental conditions have been proven to ameliorate the effect of heat stress in chicks and adult birds. As long as the climatic crises persist, heat stress may continue to require considerable attention; thus, it is imperative to explore the current happenings and pay attention to the future trajectory of heat stress effects on poultry production.

The Effect of Maternal Probiotic or Synbiotic Supplementation on Sow and Offspring Gastrointestinal Microbiota, Health, and Performance.

The increasing prevalence of antimicrobial-resistant pathogens has prompted the reduction in antibiotic and antimicrobial use in commercial pig production. This has led to increased research efforts to identify alternative dietary interventions to support the health and development of the pig. The crucial role of the GIT microbiota in animal health and performance is becoming increasingly evident. Hence, promoting an improved GIT microbiota, particularly the pioneer microbiota in the young pig, is a fundamental focus. Recent research has indicated that the sow's GIT microbiota is a significant contributor to the development of the offspring's microbiota. Thus, dietary manipulation of the sow's microbiota with probiotics or synbiotics, before farrowing and during lactation, is a compelling area of exploration. This review aims to identify the potential health benefits of maternal probiotic or synbiotic supplementation to both the sow and her offspring and to explore their possible modes of action. Finally, the results of maternal sow probiotic and synbiotic supplementation studies are collated and summarized. Maternal probiotic or synbiotic supplementation offers an effective strategy to modulate the sow's microbiota and thereby enhance the formation of a health-promoting pioneer microbiota in the offspring. In addition, this strategy can potentially reduce oxidative stress and inflammation in the sow and her offspring, enhance the immune potential of the milk, the immune system development in the offspring, and the sow's feed intake during lactation. Although many studies have used probiotics in the maternal sow diet, the most effective probiotic or probiotic blends remain unclear. To this extent, further direct comparative investigations using different probiotics are warranted to advance the current understanding in this area. Moreover, the number of investigations supplementing synbiotics in the maternal sow diet is limited and is an area where further exploration is warranted.