Dietary plant extracts improve immune responses and growth efficiency of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Influence of long-term supplementation of a formulated botanical blend on growth performance and carcass traits in feedlot steers

OBJECTIVE

The objective of this study was to determine if a formulated blend of capsicum oleoresin, clove essential oil, and garlic essential oil (Fytera Advance - Selko USA, Indianapolis IN, USA; CCG) influences measures of cattle growth, efficiency, or carcass traits, during the finishing phase in steers fed a concentrate-based diet.

METHODS

Charolais×Angus steers (n = 96; initial shrunk body weight [BW] = 391±34.0 kg) were used in a 144-d (16 February 2023 to 9 July 2023) finishing feedlot experiment in Brookings, SD, USA. Steers were individually weighed and allotted to one of 14 pens (6 to 7 steers; 7 pens/treatment) in a randomized complete block design and randomly assigned to 1 of 2 treatments: control diet without the test product (CON) or a diet including CCG at 500 mg/steer daily (CCG). Steers were fed twice daily, and bunks were managed according to a slick bunk system.

RESULTS

There were no differences (p≥0.10) in any growth performance outcomes from d 1 to 35, 36 to 70, or 71 to 98. From d 99 to 144 steers from CCG tended to have 5% greater average daily gain (p = 0.09) and 8% improved feed conversion (G:F) (p = 0.01). No differences (p≥0.15) were noted for cumulative growth performance measures. No differences were noted for any carcass measurements or categorical carcass outcomes, nor lung or liver health outcomes (p≥0.15).

CONCLUSION

The use of CCG had no influence on cumulative growth performance responses. However, the use of CCG improved G:F during the late feeding period.

Augmentation of Fermentability and Bioavailability Characteristics of Wheat Bran via the Synergistic Interaction between Arabinoxylan-Specific Degrading Enzymes and Lactic Acid Bacteria

To enhance the use of wheat bran in chicken feed, a solid-state fermentation approach was used with Lactobacillus paracasei LAC28 and Pediococcus acidilactici BCC-1, along with arabinoxylan-specific degrading enzymes (xylanase, arabinofuranosidase, feruloyl esterase, XAF). The effects of the fermentation process were evaluated both in vitro and in vivo. In the in vitro study, XAF supplementation demonstrated superior performance, significantly reducing the pH of the fermented wheat bran (FWB) and increasing lactic, acetic, and butyric acid levels, total phenol content, and free radical scavenging capacity (P < 0.05) compared to the XAF-free group. In the in vivo study, broilers were fed diets containing either unfermented wheat bran (UFWB) or FWB (fermented individually with LAC28 or BCC-1). Broilers fed FWB with BCC-1 exhibited significant improvements in body weight gain, intestinal morphology, and nutrient digestibility (P < 0.05) compared to the control group. Moreover, the FWB established a healthier microbial community in the avian gastrointestinal tract. Overall, this study demonstrated the potential of combining XAF and bacteria to enhance wheat bran fermentation, benefiting broiler intestinal health and growth. This innovative approach holds promise as a cost-efficient and sustainable strategy to improve the nutritional quality of wheat bran for animal feed applications.

Immune response enhancement by dietary supplementation with Caesalpinia sappan extract in weaned pigs challenged with porcine reproductive and respiratory syndrome virus

BACKGROUND

At present, porcine reproductive and respiratory syndrome (PRRS) caused by the PRRS virus (PRRSV) is one of the most severe epidemics impacting pig farming globally. Despite the fact that a number of studies have been conducted on potential solutions to this problem, none have proven effective. The focus of problem solving is the use of natural ingredients such as plant extracts. Popular throughout Asia, Caesalpinia sappan (CS) is a therapeutic plant that inhibits PRRSV in vitro. Therefore, this study was performed to determine the efficacy of CS extract dietary supplementation on the productive performance, antibody levels, immunological indicators, and lung pathology of PRRSV-challenged weaned pigs. A total of 32 weaned piglets (28 days old) were randomized into 4 groups and kept separately for 14 days. The treatments were organized in a 2 × 2 factorial design involving two factors: PRRSV challenge and supplementation with 1 mg/kg CS extract. The pigs in the PRRSV-challenged groups were intranasally inoculated with 2 mL of PRRSV (VR2332) containing 104 TCID50/mL, while those in the groups not challenged with PRRSV were inoculated with 2 mL of normal saline.

RESULTS

In the PRRSV-challenged group (CS + PRRSV), supplementation with CS extract led to an increase in white blood cells (WBCs) on Day 7 post infection (p < 0.05) and particularly in lymphocytes on Days 7 and 14. The antibody titer was significantly greater in the CS + PRRSV group than in the PRRSV-challenged group not administered CS (PRRSV group) on Day 14 postinfection (S/P = 1.19 vs. 0.78). In addition, CS extract administration decreased the prevalence of pulmonary lesions, which were more prevalent in the PRRSV-challenged pigs that did not receive the CS extract.

CONCLUSION

The findings of this study suggest that supplementation with CS extract is beneficial for increasing WBC counts, especially lymphocytes, increasing the levels of antibodies and reducing the prevalence of lung lesions in PRRSV-infected pigs.

Dietary glycerides of valerate ameliorate diarrhea and impact intestinal physiology and serum biomarkers in weaned piglets infected with enterotoxigenic Escherichia coli F18

In the commercial swine farm setting, the postweaning period is a critical window during which piglets are highly susceptible to infection and enterotoxigenic E. coli (ETEC)-associated diarrhea. Short-chain fatty acids and their glycerides are compounds that may influence intestinal health; however, valerate is one that has not been well-characterized for its role as a dietary supplement. Therefore, the major objective of this experiment was to investigate two forms of valerate glycerides on diarrhea, intestinal physiology, and systemic immunity of weaned pigs experimentally infected with ETEC F18. Dietary treatments included a control diet and three additional diets supplemented with 0.075% monovalerin, 0.1% monovalerin, or 0.1% trivalerin, respectively. Piglets were weaned (21 d to 24 d of age), individually housed, and experimental diets were fed through the 28-d trial period. After a 7-d period, all piglets were inoculated on three consecutive days with 1010 CFU ETEC F18/3 mL. Growth performance was monitored throughout the trial, and daily diarrhea scores were recorded. Rectal swabs were collected for bacterial culture to confirm the presence or absence of β-hemolytic coliforms throughout the trial. Serum samples were collected and analyzed for inflammatory biomarkers on days 0, 3, 6, and 21 postinoculation (PI) and untargeted metabolomics on day 6 PI. Intestinal mucosa and tissue sections were harvested from pigs sacrificed on day 7 PI for gene expression and histology analysis. All data, except for frequency of diarrhea and metabolomics, were analyzed by ANOVA using the PROC MIXED of SAS. Dietary trivalerin reduced (P < 0.05) the frequency of severe diarrhea over the entire trial period and the frequency of β-hemolytic coliforms on day 7 PI compared with the control. The intestinal villus height on day 7 PI in jejunum tissue was increased (P < 0.05) in pigs fed trivalerin. The mRNA expression of TNF-α was decreased (P < 0.05) in the trivalerin group, while that of ZO1 was increased (P < 0.05) compared with control. Throughout the trial, serum TNF-α was reduced in pigs fed trivalerin compared with control. Serum metabolites, adenosine, inosine, and shikimic acid were reduced (P < 0.05) on day 6 PI in all treatment groups compared with control. In conclusion, the present results indicate supplementing dietary valerate glycerides exhibited beneficial impacts on diarrhea, inflammation, and intestinal gene expression of piglets during the postweaning period.

Dietary Curcumin Modulating Effect on Performance, Antioxidant Status, and Immune-Related Response of Broiler Chickens Exposed to Imidacloprid Insecticide

Birds appear to be especially vulnerable to adverse impacts from insecticides. This is especially true for imidacloprid (IMI), which is considered the most toxic to avian species. Recently, prospective studies aimed at including natural alternative products to alleviate the toxic impact that comes from insecticides have been increased. Focusing on herbal growth promoters and antioxidative medicament for the poultry industry, this ongoing experiment was conducted to examine the curcumin role (CUR) in mitigating IMI-prompted detrimental effects on broilers' performance, immunity, and antioxidant status. A total number of one hundred and fifty commercial meat-type Ross 308 broilers chicks (one-day-old) were randomly allocated into equal five groups (30 chicks/group and 10 birds/replicate). The first group (C) was the control; the second group (CUR) was fed a diet containing CUR at the level of 450 mg/kg; the third group (IMI) was fed control diet for 14 days and then was fed a diet containing IMI at the level of 50 mg/kg; the fourth group (CUR+IMI co-treated) was fed a diet containing CUR+IMI; and the fifth group (CUR+IMI pro/co-treated) was fed a diet containing CUR for 14 days as protective and then a diet containing CUR+IMI for the rest of the trial. CUR supplementation either in the (CUR pro/co-treated) or (CUR co-treated) groups significantly (p < 0.05) improved final body weight and total body weight gain while decreasing the total feed intake and feed conversion ratio when compared to the IMI-exposed and non-treated birds. CUR induced a significant (p < 0.05) enhancement in hematological indices, phagocytosis %, phagocytic index, intracellular killing capacity, total proteins, globulin, liver function enzymes, lysozyme activity, and immunoglobulin-G levels compared to IMI-exposed and non-treated birds. In addition, dietary supplementation of CUR significantly (p < 0.05) modulated oxidative stress-related biomarkers in splenic tissues (total antioxidant capacity, superoxide dismutase, catalase, and glutathione peroxidase) and decreased malondialdehyde levels (p < 0.05) when compared to IMI-exposed and non-treated birds. CUR significantly down-regulated mRNA levels expression of IL-1β, TNF-α, and TLR4 and up-regulated IL-10 mRNA expression levels in spleens of birds when compared to those exposed to IMI-and non-treated. Finally, our results provided new insight into IMI-induced immuno-toxicity in broiler chickens. Furthermore, for the first time, our study informed that CUR can cause an in vivo protective effect against IMI toxicity, principally as a protective and/or as concurrent supplementation during the exposure to IMI toxicity.

Beneficial Effects of Daily Consumption of Garlic and Onion Extract Concentrate on Infectious Respiratory Diseases in Elderly Resident Volunteers

Aging is a biological process with high susceptibility to several infections. This risk increases in older patients in residential care facilities (RCF). Thus, there is a clear demand for developing preventive interventions with new therapeutic compounds that combine efficacy and safety. This could be the case of compounds derived from plants of the genus Allium spp. The purpose of this study was to evaluate the impact of a combination of a garlic and onion extract concentrate standardized in organosulfur compounds derived from propiin on the incidence of respiratory tract infections in elderly patients of RCF. Sixty-five volunteers were selected at random to receive a placebo or a single daily dose of the extract for thirty-six weeks. Different clinical visits were performed to evaluate the main respiratory diseases with an infectious origin, as well as the associated symptoms and their duration. The extract showed a clinical safety profile and significantly reduced the incidence of respiratory infections. Moreover, the treatment decreased the number and duration of the associated symptoms compared with the placebo group. For the first time, we demonstrated the protective effect of Alliaceae extract in respiratory infectious diseases in elderly healthy volunteers, which could be used prophylactically against the most common infectious respiratory diseases.

Allicin Inhibits Porcine Reproductive and Respiratory Syndrome Virus Infection In Vitro and Alleviates Inflammatory Responses

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically important pathogens to the swine industry worldwide over the past three decades. No approved effective antiviral drug is available to control this virus. The antiviral effects of allicin (diallyl thiosulfinate) on many human and animal viruses have been documented. However, the antiviral effect of allicin on PRRSV infection remains unknown. In this study, we found that allicin exhibited an inhibitory effect on HP-PRRSV and NADC30-like PRRSV in a dose-dependent manner by interfering with viral entry, replication, and assembly. Furthermore, allicin alleviated the expression of pro-inflammatory cytokines (IFN-β, IL-6, and TNFα) induced by PRRSV infection. The pro-inflammatory signaling pathways, TNF signaling pathway and MAPK signaling pathway, up-regulated by PRRSV infection were restored by allicin treatment. Taken together, these results demonstrate that allicin has antiviral activity against PRRSV and ameliorates inflammatory responses induced by PRRSV infection, suggesting that allicin is a promising drug candidate for anti-PRRSV therapy in vivo.

Pearls before Swine: Plant-Derived Wastes to Produce Low-Cholesterol Meat from Farmed Pigs-A Bibliometric Analysis Combined to Meta-Analytic Studies

Due to environmental and human factors, there is a growing amount of agri-food waste worldwide. The European Commission is incentivizing a zero-waste policy by 2025, pushing to find a "second life" for at least the avoidable ones. In this review, after summarizing the nutritional values of pork and the importance of its inclusion in human diet, a phylogenetic analysis was conducted to investigate potential differences in the structure and activity of HMGCR, which is a key enzyme in cholesterol metabolism. In addition, a bibliometric analysis combined with visual and meta-analytical studies on 1047 scientific articles was conducted to understand whether the inclusion of agro-food waste could affect the growth performance of pigs and reduce cholesterol levels in pork. Although some critical issues were highlighted, the overall data suggest a modern and positive interest in the reuse of agri-food waste as swine feed. However, although interesting and promising results have been reported in several experimental trials, further investigation is needed, since animal health and meat quality are often given marginal consideration.

Anti-Inflammatory and Antioxidative Phytogenic Substances against Secret Killers in Poultry: Current Status and Prospects

Chronic stress is recognized as a secret killer in poultry. It is associated with systemic inflammation due to cytokine release, dysbiosis, and the so-called leaky gut syndrome, which mainly results from oxidative stress reactions that damage the barrier function of the cells lining the gut wall. Poultry, especially the genetically selected broiler breeds, frequently suffer from these chronic stress symptoms when exposed to multiple stressors in their growing environments. Since oxidative stress reactions and inflammatory damages are multi-stage and long-term processes, overshooting immune reactions and their down-stream effects also negatively affect the animal's microbiota, and finally impair its performance and commercial value. Means to counteract oxidative stress in poultry and other animals are, therefore, highly welcome. Many phytogenic substances, including flavonoids and phenolic compounds, are known to exert anti-inflammatory and antioxidant effects. In this review, firstly, the main stressors in poultry, such as heat stress, mycotoxins, dysbiosis and diets that contain oxidized lipids that trigger oxidative stress and inflammation, are discussed, along with the key transcription factors involved in the related signal transduction pathways. Secondly, the most promising phytogenic substances and their current applications to ameliorate oxidative stress and inflammation in poultry are highlighted.

Dietary butyrate and valerate glycerides impact diarrhea severity and immune response of weaned piglets under ETEC F4-ETEC F18 coinfection conditions

Enterotoxigenic Escherichia coli (ETEC) causes post-weaning diarrhea in piglets, significantly impacting animal welfare and production efficiency. The two primary ETEC pathotypes associated with post-weaning diarrhea are ETEC F4 and ETEC F18. During the post-weaning period, piglets may be exposed to both ETEC F4 and ETEC F18. However, the effects of coinfection by both strains have not been studied. Short chain fatty acid feed additives, such as butyrate and valerate, are being investigated for their potential to improve animal performance and disease resistance. Therefore, this pilot experiment aimed to test the effects of butyrate glycerides or valerate glycerides on growth performance, diarrhea incidence, and immune responses of piglets under ETEC F4-ETEC F18 coinfection conditions. Twenty piglets were individually housed and assigned to one of the three dietary treatments immediately at weaning (21 to 24 d of age). The dietary treatments included control (basal diet formulation), control supplemented with 0.1% butyrate glycerides or 0.1% valerate glycerides. After a 7-d adaptation, all pigs were inoculated with ETEC F4 and ETEC F18 (0.5 × 109 CFU/1.5 mL dose for each strain) on three consecutive days. Pigs and feeders were weighed throughout the trial to measure growth performance. Fecal cultures were monitored for hemolytic coliforms, and blood samples were collected for whole blood and serum analysis. Pigs fed valerate glycerides tended (P = 0.095) to have higher final body weight compared with control. The overall severity of diarrhea was significantly (P < 0.05) lower in both treatment groups than control. Pigs fed valerate glycerides tended (P = 0.061) to have lower neutrophils and had significantly (P < 0.05) lower serum TNF-α on day 4 post-inoculation. This pilot experiment established an appropriate experimental dose for an ETEC F4-ETEC F18 coinfection disease model in weaned piglets. Results also suggest that butyrate glycerides and valerate glycerides alleviated diarrhea and regulated immune responses in piglets coinfected with ETEC F4 and ETEC F18.

A standardized method to study immune responses using porcine whole blood

BACKGROUND

Peripheral blood mononuclear cells (PBMCs) are commonly used to assess in vitro immune responses. However, PBMC isolation is a time-consuming procedure, introduces technical variability, and requires a relatively large volume of blood. By contrast, whole blood assay (WBA) is faster, cheaper, maintains more physiological conditions, and requires less sample volume, laboratory training, and equipment.

OBJECTIVES

Herein, this study aimed to develop a porcine WBA for in vitro evaluation of immune responses.

METHODS

Heparinized whole blood (WB) was diluted (non-diluted, 1/2, 1/8, and 1/16) in RPMI-1640 media, followed by phorbol myristate acetate and ionomycin. After 24 h, cells were stained for interferon (IFN)-γ secreting T-cells followed by flow cytometry, and the supernatant was analyzed for tumor necrosis factor (TNF)-α. In addition, diluted WB was stimulated by lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (poly I:C), reference strain KCTC3557 (RS), field isolate (FI), of heat-killed (HK) Streptococcus suis, and porcine reproductive and respiratory syndrome virus (PRRSV).

RESULTS

The frequency of IFN-γ⁺CD3⁺ T-cells and concentration of TNF-α in the supernatant of WB increased with increasing dilution factor and were optimal at 1/8. WB TNF-α and interleukin (IL)-10 cytokine levels increased significantly following stimulation with LPS or poly I:C. Further, FI and RS induced IL-10 production in WB. Additionally, PRRSV strains increased the frequency of IFN-γ⁺CD4^-CD8⁺ cells, and IFN-γ was non-significantly induced in the supernatant of re-stimulated samples.

CONCLUSIONS

We propose that the WBA is a rapid, reliable, and simple method to evaluate immune responses and WB should be diluted to trigger immune cells.

Thermoregulation and Performance of Dairy Cows Subjected to Different Evaporative Cooling Regimens, with or without Pepper Extract Supplementation

The objective of this study was to evaluate whether there is an interaction between pepper extract (PE) supplementation and evaporative cooling regimens on the performance, thermal comfort, and metabolism of lactating cows. The experiment was designed as a double 4 × 4 Latin square using eight multiparous Holstein cows (days in milk 147 ± 43.8 days). Treatments were a 2 × 2 factorial arrangement; two evaporative cooling regimens [sprinkler cycles of 30 s on and 4.5 min off (R5) and 30 s on and 9.5 min off (R10)] were combined with no inclusion of pepper extract (CT) or 800 mg/cow daily of PE. The inclusion of PE allowed a greater reduction in the surface temperature of the coat, and the cows remained for longer periods in the feeding area. There was an interaction between the use of PE and the climate regimen for surface temperature, which was lower for PER5. Cows experiencing greater intermittency in the spraying cycles (R10) spent 35% more time at the feeding area. A significant interaction was observed for milk production, with greater production for CTR5 compared to the other treatments. The feed efficiency for R5 was higher than that for R10. The R5 treatment combined with PE reduced water intake. There was no significant difference in serum parameters other than gamma-glutamyl transferase, with an interaction between treatments and greater activity for PER10, and total protein and albumin, which had cooling effects that were higher for R10. The two factors tested interfered in different and dissociated ways. The evaporative cooling strategies were effective, and the R5 treatment resulted in higher feed efficiency and milk production. The inclusion of PE enhanced heat reduction in cows when they were subjected to a cooling regime.

Essential Oils and COVID-19

Herbal products are a major source of herbal medicines and other medicines. Essential oils have shown various pharmacological activities, such as antiviral activity, and therefore are proposed to have potential activity against SARS-CoV-2. Due to their lipophilicity, essential oils can easily penetrate the viral membrane and cause the viral membrane to rupture. In addition, crude essential oils usually have many active constituents that can act on different parts of the virus including its cell entry, translation, transcription, and assembly. They have further beneficial pharmacological effects on the host's respiratory system, including anti-inflammatory, immune regulation, bronchiectasis, and mucolytics. This review reported potential essential oils which could be promising drugs for COVID-19 eradication. Essential oils have many advantages because they are promising volatile antiviral molecules, making them potential drug targets for the prevention and treatment of COVID-19, whether used alone or in combination with other chemotherapeutic drugs. The aim of the current review is to shed light on the potential essential oils against enveloped viruses and their proposed activity against SARS-CoV-2 which is also an enveloped virus. The objectives were to present all data reflecting the promising activities of diverse essential oils against enveloped viruses and how they could contribute to the eradication of COVID disease, especially in indoor places. The data collected for the current review were obtained through the SciFinder database, Google scholar, PubMed, and Mendeley database. The data of the current review focused on the most common essential oils which are available in the pharmaceutical market and showed noticeable activities against enveloped viruses such as HSV and influenza.

Phytochemicals as Alternatives to Antibiotics in Animal Production

Despite the continuous improvement of feed diets and recipes, animal health problems persist. For their treatment, antibiotics and chemotherapy have been shown to have side effects hard to control. The antibiotic residues in animal products may endanger human health. Since the antibiotics were restricted in animals’ diets, which were previously used to keep under control digestive and respiratory pathologies, as well as allergies, so the researchers began to search for natural alternatives. Thus, it was developed the concept of phytoadditives, and these natural plant extracts are gaining ground in animal farming. Since then, more and more animal breeders and farms are willing to use various types of phytoadditives. This chapter aims to present the most widely used phytochemicals in animal nutrition, their effects on animal production and health, and to make some recommendations on the use of phytochemicals in farm animals’ diets.

Supplementation with artificial sweetener and capsaicin alters metabolic flexibility and performance in heat-stressed and feed-restricted pigs

Substantial economic losses in animal agriculture result from animals experiencing heat stress (HS). Pigs are especially susceptible to HS, resulting in reductions in growth, altered body composition, and compromised substrate metabolism. In this study, an artificial high-intensity sweetener and capsaicin (CAPS-SUC; Pancosma, Switzerland) were supplemented in combination to mitigate the adverse effects of HS on pig performance. Forty cross-bred barrows (16.2 ± 6 kg) were assigned to one of five treatments: thermal neutral controls (TN) (22 ± 1.2 °C; 38%-73% relative humidity) with ad libitum feed, HS conditions with ad libitum feed with (HS+) or without (HS-) supplementation, and pair-fed to HS with (PF+) or without supplementation (PF-). Pigs in heat-stressed treatments were exposed to a cyclical environmental temperature of 12 h at 35 ± 1.2 °C with 27%-45% relative humidity and 12 h at 30 ± 1.1 °C with 24%-35% relative humidity for 21 d. Supplementation (0.1 g/kg feed) began 7 d before and persisted through the duration of environmental or dietary treatments (HS/PF), which lasted for 21 d. Rectal temperatures and respiration rates (RR; breaths/minute) were recorded thrice daily, and feed intake (FI) was recorded daily. Before the start and at the termination of environmental treatments (HS/PF), a muscle biopsy of the longissimus dorsi was taken for metabolic analyses. Blood samples were collected weekly, and animals were weighed every 3 d during treatment. Core temperature (TN 39.2 ± 0.02 °C, HS- 39.6 ± 0.02 °C, and HS+ 39.6 ± 0.02 °C, P < 0.001) and RR (P < 0.001) were increased in both HS- and HS+ groups, but no difference was detected between HS- and HS+. PF- pigs exhibited reduced core temperature (39.1 ± 0.02 °C, P < 0.001), which was restored in PF+ pigs (39.3 ± 0.02 °C) to match TN. Weight gain and feed efficiency were reduced in PF- pigs (P < 0.05) but not in the PF+ or the HS- or HS+ groups. Metabolic flexibility was decreased in the HS- group (-48.4%, P < 0.05) but maintained in the HS+ group. CAPS-SUC did not influence core temperature or weight gain in HS pigs but did restore core temperature, weight gain, and feed efficiency in supplemented PF pigs. In addition, supplementation restored metabolic flexibility during HS and improved weight gain and feed efficiency during PF, highlighting CAPS-SUC's therapeutic metabolic effects.

Systematic review of animal-based indicators to measure thermal, social, and immune-related stress in pigs

The intense nature of pig production has increased the animals’ exposure to stressful conditions, which may be detrimental to their welfare and productivity. Some of the most common sources of stress in pigs are extreme thermal conditions (thermal stress), density and mixing during housing (social stress), or exposure to pathogens and other microorganisms that may challenge their immune system (immune-related stress). The stress response can be monitored based on the animals’ coping mechanisms, as a result of specific environmental, social, and health conditions. These animal-based indicators may support decision making to maintain animal welfare and productivity. The present study aimed to systematically review animal-based indicators of social, thermal, and immune-related stresses in farmed pigs, and the methods used to monitor them. Peer-reviewed scientific literature related to pig production was collected using three online search engines: ScienceDirect, Scopus, and PubMed. The manuscripts selected were grouped based on the indicators measured during the study. According to our results, body temperature measured with a rectal thermometer was the most commonly utilized method for the evaluation of thermal stress in pigs (87.62%), as described in 144 studies. Of the 197 studies that evaluated social stress, aggressive behavior was the most frequently-used indicator (81.81%). Of the 535 publications examined regarding immune-related stress, cytokine concentration in blood samples was the most widely used indicator (80.1%). Information about the methods used to measure animal-based indicators is discussed in terms of validity, reliability, and feasibility. Additionally, the introduction and wide spreading of alternative, less invasive methods with which to measure animal-based indicators, such as cortisol in saliva, skin temperature and respiratory rate via infrared thermography, and various animal welfare threats via vocalization analysis are highlighted. The information reviewed was used to discuss the feasible and most reliable methods with which to monitor the impact of relevant stressors commonly presented by intense production systems on the welfare of farmed pigs.

Intestinal microbiota and its interaction to intestinal health in nursery pigs

The intestinal microbiota has gained increased attention from researchers within the swine industry due to its role in promoting intestinal maturation, immune system modulation, and consequently the enhancement of the health and growth performance of the host. This review aimed to provide updated scientific information on the interaction among intestinal microbiota, dietary components, and intestinal health of pigs. The small intestine is a key site to evaluate the interaction of the microbiota, diet, and host because it is the main site for digestion and absorption of nutrients and plays an important role within the immune system. The diet and its associated components such as feed additives are the main factors affecting the microbial composition and is central in stimulating a beneficial population of microbiota. The microbiota–host interaction modulates the immune system, and, concurrently, the immune system helps to modulate the microbiota composition. The direct interaction between the microbiota and the host is an indication that the mucosa-associated microbiota can be more effective in evaluating its effect on health parameters. It was demonstrated that the mucosa-associated microbiota should be evaluated when analyzing the interaction among diets, microbiota, and health. In addition, supplementation of feed additives aimed to promote the intestinal health of pigs should consider their roles in the modulation of mucosa-associated microbiota as biomarkers to predict the response of growth performance to dietary interventions.

Effect of supplementing lactation and nursery pig diets with capsaicin on growth performance and gene expression of nursery pigs

The objective of this study was to determine the effects of supplementing capsaicin in diets for lactating sows and their offspring on the growth performance and gene expression of pigs postweaning. Twenty-eight multiparous sows were fed corn-soybean meal-based diets without (n = 14) and with (n = 14) capsaicin (2.5 mg/kg) during a 19-d lactation period. Litters from these sows (n = 288 pigs) were weaned and assigned to 36 blocks (pens) based on maternal dietary treatment and initial body weight (BW) to provide 8 pigs/pen. Blocks were assigned randomly to one of two nursery dietary treatments (control or capsaicin supplemented diets) in a 2 × 2 factorial arrangement of treatments to provide nine replications per treatment combination. A three-phase nursery feeding program was used and consisted of feeding phase 1 (weaning to d 7), phase 2 (d 8–21), and phase 3 (d 22–38) diets postweaning, without and with 1.0, 1.3, and 1.6 mg capsaicin/kg of diet, respectively. Data were analyzed using a mixed model with the effect of nursery dietary treatment nested within sow lactation treatment, the effect of time with repeated measures, and interactions between treatments and wk postweaning. On d 38 postweaning, blood samples were collected from one pig in each pen (n = 36) with BW closest to the pen average for RNA sequencing and gene expression analysis. There were no effects of feeding capsaicin diets to lactating sows and/or their weaned offspring on BW, average daily gain, or average daily feed intake of pigs during the 35-d nursery period. However, pigs weaned from sows fed capsaicin during lactation and continuing to be fed capsaicin diets during the nursery period tended (P = 0.09) to have greater gain:feed (G:F) than pigs fed the other dietary treatments. Furthermore, there was an interaction (P < 0.01) for G:F for dietary treatment and week postweaning, where the magnitude of improvement was greater during the first week postweaning than subsequent wks. There were a limited number of differentially expressed genes among dietary treatment combinations but the greatest number occurred in offspring from sows that were fed capsaicin during lactation. In conclusion, the combination of feeding capsaicin to sows during lactation and to their offspring after weaning appears to improve gain efficiency for the first wk postweaning and may alter gene expression to a greater extent than when capsaicin is supplemented only in the nursery diets.

Dietary Supplementation With Didancao (Elephantopus scaber L.) Improves Meat Quality and Intestinal Development in Jiaji Ducks

Didancao (Elephantopus scaber L.) has been used as a traditional herbal medicine and has exhibited a beneficial role in animal health. This study aimed to investigate the effects of dietary supplementation with E. scaber on growth performance, meat quality, intestinal morphology, and microbiota composition in ducks. A total of 480 Jiaji ducks (42 days old, male:female ratio = 1:1) were randomly assigned to one of four treatments. There were six replicates per treatment, with 20 ducks per replicate. The ducks in the control group (Con) were fed a basal diet; the three experimental groups were fed a basal diet supplementation with 30 (T1), 80 (T2), and 130 mg/kg (T3) of E. scaber. After a 48-day period of supplementation, growth performance, meat quality, intestinal morphology, and microbiota composition were evaluated. The results showed that no differences were observed in the final body weight, average daily feed intake, and average daily gain among the four groups. Compared with that in the Con group, the feed conversion in the T1 and T2 groups was increased significantly; the T2 group was shown to decrease the concentration of alanine aminotransferase in serum; the T3 group was lower than the Con group in the concentration of aspartate aminotransferase and was higher than the Con group in the concentration of high-density lipoprotein-cholesterol. The highest concentration of creatinine was observed in the T1 group. The T2 group was higher than the Con group in the contents of Phe, Ala, Gly, Glu, Arg, Lys, Tyr, Leu, Ser, Thr, Asp, and total amino acids in the breast muscle. Moreover, the T2 group was higher than the Con group in the contents of meat C18:2n−6 and polyunsaturated fatty acid. The concentration of inosinic acid in the T1, T2, and T3 groups was significantly higher than that in the Con group. However, the Con group was higher than the T2 or T3 group in the Zn content. The T2 group was lower than the Con group in the jejunal crypt depth. The T3 group was higher than the Con group in the ileal villus height and the ratio of villus height to crypt depth. In addition, the T3 group had a trend to significantly increase the abundance of Fusobacteria. Compared with the Con group, the T1 and T2 groups displayed a higher abundance of Subdoligranulum. Collectively, dietary supplementation with 80 mg/kg of E. scaber improves meat quality and intestinal development in ducks.

Manno-oligosaccharide attenuates inflammation and intestinal epithelium injury in weaned pigs upon enterotoxigenic Escherichia coli K88 challenge

To explore the effect of manno-oligosaccharide (MOS) on intestinal health in weaned pigs upon enterotoxigenic Escherichia coli K88 (ETEC) challenge, thirty-two male weaned pigs were randomly assigned into four groups. Pigs fed with a basal diet or basal diet containing MOS (0·6 g/kg) were orally infused with ETEC or culture medium. Results showed that MOS significantly elevated the digestibility of crude protein and gross energy in both ETEC-challenged and non-challenged pigs (P < 0·05). MOS also elevated serum concentrations of IgA and IgM (P < 0·05), but decreased serum concentrations of TNF-α, IL-1β and IL-6 (P < 0·05) in ETEC-challenged pigs. Interestingly, MOS increased villus height and the ratio of villus height:crypt depth in duodenum and ileum (P < 0·05). MOS also increased duodenal sucrase and ileal lactase activity in ETEC-challenged pigs (P < 0·05). MOS decreased the abundance of E. coli, but increased the abundance of Lactobacillus, Bifidobacterium and Bacillus in caecum (P < 0·05). Importantly, MOS not only elevated the expression levels of zonula occludens-1 (ZO-1), claudin-1 and GLUT-2 in duodenum (P < 0·05) but also elevated the expression levels of ZO-1, GLUT-2 and L-type amino acid transporter-1 in ileum (P < 0·05) upon ETEC challenge. These results suggested that MOS can alleviate inflammation and intestinal injury in weaned pigs upon ETEC challenge, which was associated with suppressed secretion of inflammatory cytokines and elevated serum Ig, as well as improved intestinal epithelium functions and microbiota.

Jejunal Transcriptomic Profiling for Differences in Feed Conversion Ratio in Slow-Growing Chickens

Simple Summary

The slow-growing Korat chicken (KR) is economically attractive, as KR meat has a high selling price and has thus been used in Thailand to support smallholder farmers. However, low feed efficiency in KR stockbreeding makes the product less competitive and improving KR feed efficiency is central to increasing KR profitability. Using RNA sequencing, we compared the jejunal transcriptomic profiles of low- and high-feed conversion ratio (FCR) KR chickens, to identify FCR-related transcriptional variation and biological pathways. Gene Ontology and Kyoto Encyclopedia of Gene and Genome analysis revealed that the main pathways involved in KR FCR variation are related to immune response, glutathione metabolism, vitamin transport and metabolism, lipid metabolism, and neuronal and cardiac maturation, development, and growth. This is the first study to investigate, in the jejunum, the molecular genetic mechanisms affecting the FCR of slow-growing chickens. These findings will be useful in line-breeding programs to improve feed efficiency and profitability in slow-growing chicken stockbreeding.

Abstract

Improving feed efficiency is an important breeding target for the poultry industry; to achieve this, it is necessary to understand the molecular basis of feed efficiency. We compared the jejunal transcriptomes of low- and high-feed conversion ratio (FCR) slow-growing Korat chickens (KRs). Using an original sample of 75 isolated 10-week-old KR males, we took jejunal samples from six individuals in two groups: those with extremely low FCR (n = 3; FCR = 1.93 ± 0.05) and those with extremely high FCR (n = 3; FCR = 3.29 ± 0.06). Jejunal transcriptome profiling via RNA sequencing revealed 56 genes that were differentially expressed (p < 0.01, FC > 2): 31 were upregulated, and 25 were downregulated, in the low-FCR group relative to the high-FCR group. Functional annotation revealed that these differentially expressed genes were enriched in biological processes related to immune response, glutathione metabolism, vitamin transport and metabolism, lipid metabolism, and neuronal and cardiac maturation, development, and growth, suggesting that these are important mechanisms governing jejunal feed conversion. These findings provide an important molecular basis for future breeding strategies to improve slow-growing chicken feed efficiency.

The administration of diets contaminated with low to intermediate doses of deoxynivalenol and supplemented with antioxidants and binding agents slightly affects the growth, antioxidant status, and vaccine response in weanling pigs

This study aimed to evaluate the impact of grading levels of deoxynivalenol (DON) in the diet of weaned pigs, as well as the effects of a supplementation with antioxidants (AOX), hydrated sodium calcium aluminosilicates (HSCAS), and their combination on the growth, AOX status, and immune and vaccine responses against the porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2). At weaning, 336 piglets were allocated to six dietary treatments according to a randomized complete block design. Treatments were as follows: basal diet (CTRL); basal diet containing DON at 1.2 mg/kg (DON1.2); basal diet containing DON at 2.4 mg/kg (DON2.4); DON2.4 diet + a mix of AOX which included vitamins A and E at 20,000 IU and 200 IU/kg feed respectively, selenized yeast at 0.3 mg/kg, and a grape seed extracts at 100 mg/kg feed (DON2.4 + AOX); DON2.4 diet + the mix of AOX and the modified HSCAS mentioned above (DON2.4 + AOX + HSCAS); DON2.4 + AOX + HSCAS. Pigs were vaccinated against PRRSV and PCV2 at 7 d; on 0, 14, and 35 d, growth performance was recorded, and blood samples were collected in order to evaluate the oxidative status, inflammatory blood markers, lymphocyte blastogenic response, and vaccine antibody response. Increasing intake of DON resulted in a quadratic effect at 35 d in the lymphocyte proliferative response to concanavalin A and PCV2 as well as in the anti-PRRSV antibody response, whereas the catalase activity decreased in DON2.4 pigs compared with the CTRL and DON1.2 groups (P ≤ 0.05). Compared with the DON2.4 diet, the AOX supplementation slightly reduced gain to feed ratio (P = 0.026) and increased the ferric reducing ability of plasma as well as α-tocopherol concentration (P < 0.05), whereas the association of AOX + HSCAS increased the anti-PRRSV IgG (P < 0.05). Furthermore, the HSCAS supplement reduced haptoglobin levels in serum at 14 d compared with the DON2.4 group; however, its concentration decreased in all the experimental treatments from 14 to 35 d and particularly in the DON2.4 + AOX pigs, whereas a different trend was evidenced in the DON2.4 + HSCAS group, where over the same period haptoglobin concentration increased (P < 0.05). Overall, our results show that the addition of AOX and HSCAS in the diet may alleviate the negative effects due to DON contamination on the AOX status and immune response of vaccinated weanling pigs.

Environmentally enriched housing conditions affect pig welfare, immune system and gut microbiota in early life

BACKGROUND

Conventional pig housing and management conditions are associated with gastrointestinal pathophysiology and disease susceptibility in early life. Developing new strategies to reduce both therapeutic and prophylactic antibiotic use is urgent for the sustainable swine production globally. To this end, housing methodology providing effective environmental enrichment could be a promising alternative approach to reduce antibiotic usage, as it has been proven to positively influence pig welfare and immune status and reduce susceptibility to infections. It is, however, poorly understood how this enriched housing affects systemic and local pulmonary immune status and gut microbiota colonization during early life. In the present study, we compared the effects of two housing conditions, i.e., conventional housing: (CH) versus enriched housing (EH), on immune status and gut microbiota from birth until 61 days of age.

RESULTS

The expected benefits of enrichment on pig welfare were confirmed as EH pigs showed more positive behaviour, less aggression behaviour during the weaning transition and better human animal relation during the post weaning phase. Regarding the pigs' immune status, EH pigs had higher values of haemoglobin and mean corpuscular volume in haematological profiles and higher percentages of T cells and cytotoxic T cells in peripheral blood. Furthermore, EH pigs showed higher ex vivo secretion of IL1ß and TNF-α after lipopolysaccharide stimulation of whole blood than CH pigs. The structure of the developing faecal microbiota of CH and EH pigs significantly differed as early as day 12 with an increase in the relative abundance of several bacterial groups known to be involved in the production of short chain fatty acids, such as Prevotella_2, Christensenellaceae_R_7_group and Ruminococcus gauvreauii group. Furthermore, the main difference between both housing conditions post weaning was that on day 61, CH pigs had significantly larger inter-individual variation of ileal and colonic microbiota than EH pigs. In addition to housing, other intrinsic factors (e.g., sex) were associated with gut microbiota development and immune competence.

CONCLUSIONS

In addition to the known welfare benefits for pigs, environmentally enriched housing also positively drives important aspects of the development of the immune system and the establishment of gut microbiota in early life. Consequently, EH may contribute to increasing productivity of pigs and reducing antibiotic use.

Effect of Ethanolic Caesalpinia sappan Fraction on In Vitro Antiviral Activity against Porcine Reproductive and Respiratory Syndrome Virus

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major epidemic in pig production, leading to economic losses in the pig industry worldwide. The use of medicinal plants with antiviral properties might be useful help to prevent and control PRRSV outbreaks. Caesalpinia sappan (CS) heartwood is an important herbal ingredient used in Thai folk medicine, possessing various biological activities, including antiviral activity. The present study focuses on the in vitro antiviral activity against PRRSV of a semi-purified fraction of ethanolic CS crude extract using preparative high-performance liquid chromatography. Qualification of the fractions illustrating positive antiviral activity was carried out with liquid chromatography–quadrupole time-of-flight mass spectrometry. The preparative chromatography separated the crude extract into six consecutive fractions, among which the first fraction showed potential antiviral activity by inhibiting PRRSV replication in a MARC-145 monolayer (virus titer 2.75 median tissue culture infective dose (TCID₅₀)/mL (log₁₀) vs. 9.50 median log10 TCID₅₀/mL of the control) at 72 h post-infection, and this fraction included byakangelicin, brazilin, naringenin, and brazilein. These results provide useful information for further study to effectively develop the CS bioactive antiviral compounds against PRRSV as a feed additive or veterinary drug in the pig industry.

Garlic Essential Oil as Promising Option for the Treatment of Acute Campylobacteriosis-Results from a Preclinical Placebo-Controlled Intervention Study

Since human infections with Campylobacter jejuni including antibiotic-resistant strains are rising worldwide, natural compounds might constitute promising antibiotics-independent treatment options for campylobacteriosis. Since the health-beneficial properties of garlic have been known for centuries, we here surveyed the antimicrobial and immune-modulatory effects of garlic essential oil (EO) in acute experimental campylobacteriosis. Therefore, secondary abiotic IL-10^-/- mice were orally infected with C. jejuni strain 81-176 and garlic-EO treatment via the drinking water was initiated on day 2 post-infection. Mice from the garlic-EO group displayed less severe clinical signs of acute campylobacteriosis as compared to placebo counterparts that were associated with lower ileal C. jejuni burdens on day 6 post-infection. Furthermore, when compared to placebo application, garlic-EO treatment resulted in alleviated colonic epithelia cell apoptosis, in less pronounced C. jejuni induced immune cell responses in the large intestines, in dampened pro-inflammatory mediator secretion in intestinal and extra-intestinal compartments, and, finally, in less frequent translocation of viable pathogens from the intestines to distinct organs. Given its potent immune-modulatory and disease-alleviating effects as shown in our actual preclinical placebo-controlled intervention study, we conclude that garlic-EO may be considered as promising adjunct treatment option for acute campylobacteriosis in humans.

Carbohydrates effects on nutrition and health functions in pigs

The greatest improvement in carbohydrates studies on pig nutrition and health is that carbohydrates are classified more clearly, which is based not only on their chemical structure but also on their physiological characteristics. Besides its primary energy source, different types and structures of carbohydrates are a benefit for nutrition and health functions in pigs, which are involved in promoting growth performance and intestinal functions, regulating the community of gut microbiota, and modulating the lipids and glucose metabolism. The underlying mechanism of carbohydrates regulates the lipids and glucose metabolism through their metabolites (short-chain fatty acids [SCFAs]) and mainly via the SCFAs-GPR43/41-PYY/GLP1, SCFAs-AMP/ATP-AMPK, and SCFAs-AMPK-G6Pase/PEPCK pathways. Emerging research had evaluated an optimal combination in different types and structures of carbohydrates, which could enhance growth performance and nutrient digestibility, promote intestinal functions, and increase the abundances of butyrate-producing bacteria in pigs. Overall, compelling evidence supports the notion that carbohydrates play important roles in both nutrition and health functions in pigs. Moreover, identifying the carbohydrates combinations will be of both theoretical and practical values for developing the technology of carbohydrates balance in pigs.

Intestinal Health of Pigs Upon Weaning: Challenges and Nutritional Intervention

The primary goal of nursery pig management is making a smooth weaning transition to minimize weaning associated depressed growth and diseases. Weaning causes morphological and functional changes of the small intestine of pigs, where most of the nutrients are being digested and absorbed. While various stressors induce post-weaning growth depression, the abrupt change from milk to solid feed is one of the most apparent challenges to pigs. Feeding functional feed additives may be viable solutions to promote the growth of nursery pigs by enhancing nutrient digestion, intestinal morphology, immune status, and by restoring intestinal balance. The aim of this review was to provide available scientific information on the roles of functional feed additives in enhancing intestinal health and growth during nursery phase. Among many potential functional feed additives, the palatability of the ingredient and the optimum supplemental level are varied, and these should be considered when applying into nursery pig diets. Considering different stressors pigs deal with in the post-weaning period, research on nutritional intervention using a single feed additive or a combination of different additives that can enhance feed intake, increase weight gain, and reduce mortality and morbidity are needed to provide viable solutions for pig producers. Further research in relation to the feed palatability, supplemental level, as well as interactions between different ingredients are needed.

Supplementing chestnut tannins in the broiler diet mediates a metabolic phenotype of the ceca

As the demand for alternatives to antibiotic growth promoters (AGP) increases in food animal production, phytobiotic compounds gain popularity because of their ability to mimic the desirable bioactive properties of AGP. Chestnut tannins (ChT) are one of many phytobiotic compounds used as feed additives, particularly in South America, for broilers because of its favorable antimicrobial and growth promotion capabilities. Although studies have observed the microbiological and immunologic effects of ChT, there is a lack of studies evaluating the metabolic function of ChT. Therefore, the objective of this study was to characterize the cecal metabolic changes induced by ChT inclusion and how they relate to growth promotion. A total of 200 day-of-hatch broiler chicks were separated into 2 feed treatment groups: control and 1% ChT. The ceca from all the chicks in the treatment groups were collected on day 2, 4, 6, 8, and 10 after hatch. The cytokine mRNA quantitative RT-PCR was determined using TaqMan gene expression assays for IL-1B, IL-6, IL-8, IL-10, and interferon gamma quantification. The cytokine expression showed highly significant increased expressions of IL-6 and IL-10 on day 2 and 6, whereas the other proinflammatory cytokines did not have significantly increased expression. The results from the kinome array demonstrated that the ceca from birds fed with 1% ChT had significant (P < 0.05) metabolic alterations based on the number of peptides when compared with the control group across all day tested. The increased expression of IL-6 appeared to be strongly indicative of altered metabolism, whereas the increased expression of IL-10 indicated the regulatory effect against other proinflammatory cytokines other than IL-6. The ChT initiate a metabolic mechanism during the first 10 d in the broiler. For the first time, we show that a phytobiotic product initially modulates metabolism while also potentially supporting growth and feed efficiency downstream. In conclusion, a metabolic phenotype alteration in the ceca of chickens fed ChT may indicate the importance of enhanced broiler gut health.

Insight into the intestinal microbiome of farrowing sows following the administration of garlic (Allium sativum) extract and probiotic bacteria cultures under farming conditions

Background

Due to the tendency to reduce antibiotic use in humans and animals, more attention is paid to feed additives as their replacement. Crucial role of feed additives is to improve the health status, production efficiency and performance. In this original research, we estimate the potential influence of garlic (Allium sativum) extract and probiotic formula including Enterococcus faecium, Lactobacillus rhamnosus and Lactobacillus fermentum on the intestinal microbiota of sows, using the next generation sequencing method (NGS).

Results

Our results indicate that the overall species richness as well as the composition of swine gut microbiota may be shaped by regular feeding with supplemented additives. On the Family and Genus level both additives (garlic extract and probiotics) seem to decrease microbiome diversity and richness. However, when it comes to garlic supplementation, we found the opposite trend on the Species level.

Conclusions

The analysis of the selected microbial function indicates that both additives used in this study (garlic extract and composition of probiotics) seem to create a greater metabolic potential than estimated in a control group of sows. A general trend of losing or decreasing members of pathogenic species in the swine microbiome seems to occur in relation to both supplemented additives. In the prevention of some bacterial diseases supplemented additives could be considered for future use.

Effects of an F18 enterotoxigenic Escherichia coli challenge on growth performance, immunological status, and gastrointestinal structure of weaned pigs and the potential protective effect of direct-fed microbial blends

The objective of this experiment was to investigate the impact of an F18 enterotoxigenic Escherichia coli (ETEC) challenge on growth performance, aspects of intestinal function, and selected immune responses of piglets, as well as to evaluate potential protective effects of direct-fed microbial (DFM) blends. Seventy-two weaned piglets (6.4 ± 0.2 kg body weight [BW]; ~21 d of age) were assigned to one of four treatments: 1) NC: Nonchallenged (n = 10), 2) positive challenged control (PC): F18 ETEC-challenged (n = 10), 3) PC + DFM1 (n = 8; three strains of Bacillus amyloliquefaciens; 7.5 × 10⁵ colony-forming units [cfu]/g), or 4) PC + DFM2 (n=8; 2 strains of B. amyloliquefaciens and one strain of Bacillus subtilis; 1.5 × 10⁵ cfu/g). Feed intake and BW were recorded on day 0, 7, and 17. Pigs were sham-infected either with 6 mL phosphate-buffered saline or inoculated with 6 mL F18 ETEC (~1.9 × 10⁹ cfu/mL) on day 7 (0 d postinoculation [dpi]). All ETEC-challenged pigs were confirmed to be genetically susceptible to F18. Pigs had ad libitum access to feed and water throughout the 17-d trial. Fecal scores were visually ranked and rectal temperatures were recorded daily. To evaluate ETEC shedding, fecal swabs were collected on dpi 0, 1, 2, 3, 5, 7, and 10. Blood samples were collected on dpi 0, 1, 2, 4, 7, and 10. Ileal tissues were collected at necropsy on dpi 10. All challenged treatments had lower final BW, decreased average daily gain (ADG), and average daily feed intake (ADFI) during the 10-d postchallenge period (P < 0.01). The DFM2 treatment increased E. coli shedding on dpi 2 and decreased iton dpi 7 (P < 0.05) compared with the PC. Rectal temperature decreased across all challenged treatments (P < 0.01). Ileal mRNA abundance of occludin (OCLN) and zonula occludens-1 (ZO-1) decreased in PC and DFM1 compared with NC (P < 0.05). Pigs fed DFM2 had intermediate ileal mRNA abundance of OCLN and increased ZO-1 mRNA compared with pigs in PC (P < 0.05). Interleukin 8 (IL-8) increased in the plasma of PC and DFM2 on dpi 2 compared with NC (P < 0.05). Mucosal IL-8 increased in PC compared with NC (P < 0.05). All challenged treatments tended to have elevated tumor necrosis factor-α (TNF-α) mRNA abundance compared with NC (P < 0.10). Challenged pigs had reduced secretory immunoglobulin A and villus height compared with NC pigs (P < 0.05). The impact of an ETEC challenge on intestinal function and the immune system has been revealed, information critical to developing improved treatment regimes.

Dietary supplementation of artificial sweetener and capsicum oleoresin as a strategy to mitigate the negative consequences of heat stress on pig performance

Pigs exposed to elevated ambient temperatures exhibit reduced daily gain, alterations in muscle and fat deposition, and decreased health. Negative aspects of gastrointestinal (GI) function, integrity, and permeability also occur. High-intensity sweeteners can ameliorate the negative effects of heat stress (HS) by increasing GI glucagon-like peptide-2 production while capsicum oleoresin has been shown to reduce inflammatory response. The effects of an artificial high-intensity sweetener and capsicum oleoresin (CAPS-SUC; TakTik X-Hit, Pancosma, Switzerland) on growth performance of pigs were examined. Forty-eight pigs (12 wk of age, 43.2 ± 4.3 kg) were assigned to six treatments: thermoneutral conditions (21 ± 1.1 °C; 40% to 70% relative humidity) fed ad libitum with (TN+) or without supplement (TN-), heat stress (35 ± 1 °C; 20% to 40% relative humidity) fed ad libitum with (HS+) or without supplement (HS-), and thermoneutral conditions pair-fed to HS intake with (PFTN+) or without supplement (PFTN-). Supplementation (0.1 g/kg feed) began 2 d prior to the 3-d environmental treatment period. Body weights (BWs) and blood samples were collected on days -1 and 3. Rectal temperature (RT) and respiration rate (RR) were measured thrice daily and the feed intake (FI) was recorded daily. Intestinal sections were collected for histology. Pigs in HS conditions exhibited increased RT (~1.2 °C) and RR (~2.7-fold) compared with TN and PFTN groups (P < 0.01). HS+ animals had increased RR when compared with HS- animals (P < 0.02). Heat stress decreased FI compared with TN. HS and PFTN decreased (P < 0.05) average daily gain compared with TN. Supplement did not alter the BW gain. HS and PFTN decreased (P < 0.05) Gain:Feed compared with TN during environmental treatment. Supplementation with CAPS-SUC increased Gain:Feed by 0.12 (P < 0.05). Circulating glucose concentrations tended to decrease in CAPS-SUC vs. non-supplemented HS and PFTN animals (P ≤ 0.1). Circulating insulin concentrations as well as monocyte count increased in HS compared with PFTN (P < 0.04) but did not differ from TN and likely linked to altered FI. CAPS-SUC increased basophil count (P < 0.02), irrespective of environment. Ileal villus height tended to decrease during HS and PFTN compared with TN (P < 0.08), indicating an effect of intake. Overall, CAPS-SUC supplementation increased pig feed efficiency and may improve immune response.

Antiviral potential of garlic (Allium sativum) and its organosulfur compounds: A systematic update of pre-clinical and clinical data

BACKGROUND

Garlic (Allium sativum L.) is a common herb consumed worldwide as functional food and traditional remedy for the prevention of infectious diseases since ancient time. Garlic and its active organosulfur compounds (OSCs) have been reported to alleviate a number of viral infections in pre-clinical and clinical investigations. However, so far no systematic review on its antiviral effects and the underlying molecular mechanisms exists.

SCOPE AND APPROACH

The aim of this review is to systematically summarize pre-clinical and clinical investigations on antiviral effects of garlic and its OSCs as well as to further analyse recent findings on the mechanisms that underpin these antiviral actions. PubMed, Cochrane library, Google Scholar and Science Direct databases were searched and articles up to June 2020 were included in this review.

KEY FINDINGS AND CONCLUSIONS

Pre-clinical data demonstrated that garlic and its OSCs have potential antiviral activity against different human, animal and plant pathogenic viruses through blocking viral entry into host cells, inhibiting viral RNA polymerase, reverse transcriptase, DNA synthesis and immediate-early gene 1(IEG1) transcription, as well as through downregulating the extracellular-signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) signaling pathway. The alleviation of viral infection was also shown to link with immunomodulatory effects of garlic and its OSCs. Clinical studies further demonstrated a prophylactic effect of garlic in the prevention of widespread viral infections in humans through enhancing the immune response. This review highlights that garlic possesses significant antiviral activity and can be used prophylactically in the prevention of viral infections.

Dietary plant extracts modulate gene expression profiles in alveolar macrophages of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

BACKGROUND

Our previous study showed that 3 plant extracts enhanced the immune responses and growth efficiency of weaned pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV), which is one of the most economically important disease in swine industry. However, each plant extract differently effected on growth efficiency and immune responses. Therefore, the objective of this study was conducted to characterize the effects and investigate the potential underlying mechanisms of 3 plant extracts on gene expression of alveolar macrophages in weaned pigs experimentally infected with PRRSV.

RESULTS

PRRSV infection altered (P < 0.05) the expression of 1,352 genes in pigs fed the control (CON; 755 up, 597 down). Compared with the infected CON, feeding capsicum (CAP), garlic botanical (GAR), or turmeric oleoresin (TUR) altered the expression of 46 genes (24 up, 22 down), 134 genes (59 up, 75 down), or 98 genes (55 up, 43 down) in alveolar macrophages of PRRSV-infected pigs, respectively. PRRSV infection up-regulated (P < 0.05) the expression of genes related to cell apoptosis, immune system process, and response to stimulus, but down-regulated (P < 0.05) the expression of genes involved in signaling transduction and innate immune response. Compared with the infected CON, feeding TUR or GAR reduced (P < 0.05) the expression of genes associated with antigen processing and presentation, feeding CAP up-regulated (P < 0.05) the expression of genes involved in antigen processing and presentation. Supplementation of CAP, GAR, or TUR also enhanced (P < 0.05) the expression of several genes related to amino acid metabolism, steroid hormone synthesis, or RNA degradation, respectively.

CONCLUSIONS

The results suggest that 3 plant extracts differently regulated the expression of genes in alveolar macrophages of PRRSV-infected pigs, especially altering genes involved in immunity.

Standardized Plant Extract Alleviates the Negative Effects of FMD Vaccination on Animal Performance

Simple Summary

Foot and Mouth Disease (FMD) is among the viral diseases causing poor growth performance and reduced immune status, leading to heavy economic losses in livestock. The vaccination of animals against FMD may lead to vaccination stress, thereby reducing the growth performance of animals. The growth promoting effects of a plant extract (consisting of capsicum and turmeric oleoresins) against FMD vaccinated growing pigs are evaluated in the present study. It was determined that the supplementation of the plant extract significantly improved performance and increased the antibody titer against FMD antigens. However, the immune parameters measured at days 10, 15, 20 and 25 post-FMD vaccination remained unaffected.

Abstract

The present study was conducted to assess the efficacy of a plant extract (PE) on growth performance and immune status in foot and mouth disease (FMD)-vaccinated growing pigs. A total of 120 crossed ((Landrace × Yorkshire) × Duroc) growing pigs with an average initial body weight (BW) of 24.66 ± 2.34 kg and an average age of 70 days were randomized into three groups (10 pens; 4 pigs per pen per treatment) as follows: a nonvaccinated negative control group (NV), a FMD vaccinated group (OV), and a third group received a 0.0125% PE supplement after vaccination (PV), in a 6-week trial. The PV group receiving PE supplementation increased (p < 0.05) the BW compared with the OV group, and average daily gain (ADG) during days 1–14, overall and gain-to-feed ratio (G: F) in days 1–14, and dry matter (DM) digestibility at week 6 were higher (p < 0.05) in the PV compared with the OV group. A significant increase (p < 0.05) in haptoglobin concentration was observed in the OV group compared with the NV group at 25 days postvaccination. The inhibition percentage of antibodies against FMD in the sera reached above 50% in the PV group 5 days earlier than in the OV group. The findings suggest that the inclusion of PE in the diet promoted the performance of vaccinated growing pigs.

Nutritional Regulation of Gut Barrier Integrity in Weaning Piglets

Simple Summary

Weaning is a very stressful period in the piglet’s life in intensive farming: it is a sudden process occurring between three to four weeks of age, when the gastrointestinal tract (GIT) is still immature. The GIT is formed by the epithelial, immune and enteric nervous system which controls epithelial barrier integrity as well as gut functions including the transport of luminal nutrients, water and electrolytes. Early weaning is characterized by a breakdown of these gut functions, an increase in intestinal permeability and the appearance of gastrointestinal functional disorders, which can have long-lasting consequences in the pig’s life. Weaning, therefore, requires the correct level of nutrients, high quality ingredients, and management, which are directed primarily at encouraging rapid feed intake whilst reducing mortality and morbidity. This review describes the organization of the GIT and highlights the interactions between feed components and the morphology and physiology of the epithelial barrier. Novel dietary strategies focused on improving gut health are also discussed, considering the impacts of selected feed ingredients or additives on the GIT such as functional amino acids, phytochemicals and organic acids.

Abstract

Weaning is very stressful for piglets and leads to alterations in the intestinal barrier, a reduction in nutrient absorption and a higher susceptibility to intestinal diseases with heavy economic losses. This review describes the structures involved in the intestinal barrier: the epithelial barrier, immune barrier and the enteric nervous system. Here, new insights into the interactions between feed components and the physiology and morphology of the epithelial barrier are highlighted. Dietary strategies focused on improving gut health are also described including amino acids, phytochemicals and organic acids.

Effects of dietary soy isoflavones and soy protein source on response of weanling pigs to porcine reproductive and respiratory syndrome viral infection

Porcine reproductive and respiratory syndrome virus (PRRSV) is the most prevalent disease of swine globally. Infection of weanling pigs with PRRSV leads to a complex immune response resulting in significant disease and decreased growth performance. Previous experimental evidence suggests that increasing concentrations of soybean meal in the diet of young pigs confer benefits in terms of growth performance and immune parameters. The objective of this experiment was to identify potential modes of action for this benefit, specifically the ability for soy-derived isoflavones (ISF) to confer immunological benefits to young pigs infected with PRRSV. Four dietary treatments differing in soy protein source (soy protein concentrate vs. enzyme-treated soybean meal) and ISF supplementation (none vs. 1,500 mg total ISF/kg) were fed; the control diet (CON) contained soy protein concentrate and no supplemental ISF. Weanling pigs (60 barrows, 21 d of age, 5.71 ± 0.44 kg) from a naturally Mycoplasma hyopneumoniae (Mh)-infected source herd were individually housed in disease containment chambers and provided ad libitum access to experimental diets for 7 d before receiving either a sham inoculation or a 9.28 × 103 50% tissue culture infective dose of PRRSV at 28 d of age (0 d postinoculation). A total of 5 experimental treatments included an uninfected group receiving the CON diet, plus four infected groups each receiving a different dietary treatment. Growth performance and rectal temperatures were recorded throughout the study, and blood was collected for quantification of serum PRRSV load, presence of anti-PRRSV antibodies, differential complete blood counts, cytokine concentrations, and T-cell immunophenotyping. Data were analyzed as a 2-way or 3-way ANOVA for all treatments including PRRSV-infected pigs, in addition to a single degree of freedom contrast to compare uninfected and infected pigs receiving the CON diet. PRRSV-infection reduced growth rate and efficiency compared with noninfected controls with minimal influences by ISF. Supplemental ISF reduced PRRSV-induced band neutrophilia and improved cytotoxic-to-helper T-cell ratios. These results suggest that ISF contribute to activation of adaptive immune system pathways and could benefit recovery from and clearance of PRRSV infections.

Antibiotic Application and Resistance in Swine Production in China: Current Situation and Future Perspectives

To meet increasing demand for animal protein, swine have been raised in large Chinese farms widely, using antibiotics as growth promoter. However, improper use of antibiotics has caused serious environmental and health risks, in particular Antimicrobial resistance (AMR). This paper reviews the consumption of antibiotics in swine production as well as AMR and the development of novel antibiotics or alternatives in China. The estimated application of antibiotics in animal production in China accounted for about 84240 tons in 2013. Overuse and abuse of antibiotics pose a great health risk to people through food-borne antibiotic residues and selection for antibiotic resistance. China unveiled a national plan to tackle antibiotic resistance in August 2016, but more support is needed for the development of new antibiotics or alternatives like plant extracts. Antibiotic resistance has been a major global challenge, so international collaboration between China and Europe is needed.

Nutritional Intervention for the Intestinal Development and Health of Weaned Pigs

Weaning imposes simultaneous stress, resulting in reduced feed intake, and growth rate, and increased morbidity and mortality of weaned pigs. Weaning impairs the intestinal integrity, disturbs digestive and absorptive capacity, and increases the intestinal oxidative stress, and susceptibility of diseases in piglets. The improvement of intestinal development and health is critically important for enhancing nutrient digestibility capacity and disease resistance of weaned pigs, therefore, increasing their survival rate at this most vulnerable stage, and overall productive performance during later stages. A healthy gut may include but not limited several important features: a healthy proliferation of intestinal epithelial cells, an integrated gut barrier function, a preferable or balanced gut microbiota, and a well-developed intestinal mucosa immunity. Burgeoning evidence suggested nutritional intervention are one of promising measures to enhance intestinal health of weaned pigs, although the exact protective mechanisms may vary and are still not completely understood. Previous research indicated that functional amino acids, such as arginine, cysteine, glutamine, or glutamate, may enhance intestinal mucosa immunity (i.e., increased sIgA secretion), reduce oxidative damage, stimulate proliferation of enterocytes, and enhance gut barrier function (i.e., enhanced expression of tight junction protein) of weaned pigs. A number of feed additives are marketed to assist in boosting intestinal immunity and regulating gut microbiota, therefore, reducing the negative impacts of weaning, and other environmental challenges on piglets. The promising results have been demonstrated in antimicrobial peptides, clays, direct-fed microbials, micro-minerals, milk components, oligosaccharides, organic acids, phytochemicals, and many other feed additives. This review summarizes our current understanding of nutritional intervention on intestinal health and development of weaned pigs and the importance of mechanistic studies focusing on this research area.

Phytochemicals as antibiotic alternatives to promote growth and enhance host health

There are heightened concerns globally on emerging drug-resistant superbugs and the lack of new antibiotics for treating human and animal diseases. For the agricultural industry, there is an urgent need to develop strategies to replace antibiotics for food-producing animals, especially poultry and livestock. The 2nd International Symposium on Alternatives to Antibiotics was held at the World Organization for Animal Health in Paris, France, December 12-15, 2016 to discuss recent scientific developments on strategic antibiotic-free management plans, to evaluate regional differences in policies regarding the reduction of antibiotics in animal agriculture and to develop antibiotic alternatives to combat the global increase in antibiotic resistance. More than 270 participants from academia, government research institutions, regulatory agencies, and private animal industries from >25 different countries came together to discuss recent research and promising novel technologies that could provide alternatives to antibiotics for use in animal health and production; assess challenges associated with their commercialization; and devise actionable strategies to facilitate the development of alternatives to antibiotic growth promoters (AGPs) without hampering animal production. The 3-day meeting consisted of four scientific sessions including vaccines, microbial products, phytochemicals, immune-related products, and innovative drugs, chemicals and enzymes, followed by the last session on regulation and funding. Each session was followed by an expert panel discussion that included industry representatives and session speakers. The session on phytochemicals included talks describing recent research achievements, with examples of successful agricultural use of various phytochemicals as antibiotic alternatives and their mode of action in major agricultural animals (poultry, swine and ruminants). Scientists from industry and academia and government research institutes shared their experience in developing and applying potential antibiotic-alternative phytochemicals commercially to reduce AGPs and to develop a sustainable animal production system in the absence of antibiotics.

Non-antibiotic feed additives in diets for pigs: A review

A number of feed additives are marketed to assist in boosting the pigs' immune system, regulate gut microbiota, and reduce negative impacts of weaning and other environmental challenges. The most commonly used feed additives include acidifiers, zinc and copper, prebiotics, direct-fed microbials, yeast products, nucleotides, and plant extracts. Inclusion of pharmacological levels of zinc and copper, certain acidifiers, and several plant extracts have been reported to result in improved pig performance or improved immune function of pigs. It is also possible that use of prebiotics, direct-fed microbials, yeast, and nucleotides may have positive impacts on pig performance, but results have been less consistent and there is a need for more research in this area.

Immunomodulatory effects of phytogenics in chickens and pigs - A review

Environmental stressors like pathogens and toxins may depress the animal immune system through invasion of the gastrointestinal tract (GIT) tract, where they may impair performance and production, as well as lead to increased mortality rates. Therefore, protection of the GIT tract and improving animal health are top priorities in animal production. Being natural-sourced materials, phytochemicals are potential feed additives possessing multiple functions, including: anti-inflammatory, anti-fungal, anti-viral and antioxidative properties. This paper focuses on immunity-related physiological parameters regulated by phytochemicals, such as carvacrol, cinnamaldehyde, curcumin, and thymol; many studies have proven that these phytochemicals can improve animal performance and production. On the molecular level, the impact of inflammatory gene expression on underlying mechanisms was also examined, as were the effects of environmental stimuli and phytochemicals in initiating nuclear factor kappa B and mitogen-activated protein kinases signaling pathways and improving health conditions.

Essential role for simulation models in animal research and application

Simulation models have been used productively to aid understanding of animal biology and production systems. Emphasis here is on pig growth models, but the principles apply also to other species and other outcomes. Main applications for such models are direct use within a production system, indirect use across production systems and guidance of research. Most useful models are dynamic and mechanistic; most are deterministic but some gain added utility from stochasticity. Several pig growth models have predicted growth rate, feed efficiency and body and carcass composition from inputs, including protein accretion capacity and diet composition and intake. They have been so successful that now attention can be applied elsewhere. Pigs in commercial production fail to achieve their potential growth, presumably because of various stressors, including disease, and the gap between actual and potential growth is a rich target for future simulation models. Models should address activation of the innate immune system separately from clinical disease. They can provide special benefits from prediction of the impacts of several health-promoting technologies, including those in feed.

Anethol, cinnamaldehyde, and eugenol inclusion in feed affects postweaning performance and feeding behavior of piglets

The early exposure of the fetus to certain volatiles may result in a further preference for these compounds later in life and could positively affect the acceptance of feed containing a similar flavor and the zootechnical responses. The study consisted of 2 trials to determine if including Fluidarom 1003 (a commercially flavored feed additive containing >25% anethol and cinnamaldehyde and >10% eugenol; Norel S.A., Madrid, Spain, Spain) in sow and postweaning piglet diets 1) provokes the presence or absence of 3 major volatile compounds (anethol, cinnamaldehyde, and eugenol) in amniotic fluid and milk, affecting piglet performance (BW, ADG, ADFI, and feed conversion ratio) after weaning, and 2) modifies creep feed consumption and feed preference in a 2-choice test. The major compounds, anethol, cinnamaldehyde, and eugenol, were detected in amniotic fluid; however, only traces were observed in milk. The inclusion of flavor in the sow diets improved piglet consumption and growth after weaning ( = 0.001). Furthermore, the positive reward associated with the flavor included in the sow diet was stronger when piglets were offered a nonflavored creep feed ( < 0.05). Therefore, early exposure of pigs' fetuses to maternal dietary clues at the end of gestation might allow for conditioning pigs after weaning.

Effects of rumen-protected Capsicum oleoresin on immune responses in dairy cows intravenously challenged with lipopolysaccharide

The objective of this experiment was to investigate the effects of rumen-protected Capsicum oleoresin (RPC) on productivity and immune responses including feed intake, milk yield and composition, white and red blood cells, lipid peroxidation, and blood concentration of cortisol, haptoglobin, glucose, and insulin in lactating dairy cows experimentally challenged with lipopolysaccharide (LPS). The experiment was a replicated 3 × 3 Latin square design with 9 multiparous Holstein cows in three 28-d periods. Treatments were 0 (control), 100, and 200 mg of RPC/cow per day, mixed with small portions of the total mixed ration and top-dressed. Bacterial LPS was intravenously administered at 1.0 μg/kg of body weight in the last week of each experimental period, and blood samples were collected at 0, 2, 4, 8, and 24 h after administration. Dry matter intake, milk yield, and white blood cells including neutrophils, lymphocytes, monocytes, and eosinophils were decreased, and rectal temperature, hemoglobin, and serum concentrations of cortisol and haptoglobin were increased by LPS. Red blood cells, platelets, and plasma concentration of thiobarbituric acid reactive substances were not affected by LPS. Dry matter intake, milk yield, and milk composition in the 5 d post-LPS challenge were not affected by RPC. Rectal temperature, white blood cells, red blood cells, hemoglobin, and platelets were also not affected by RPC. Compared with the control, RPC tended to decrease cortisol at 2 h following LPS challenge and decreased haptoglobin concentration in serum across sampling points. Concentration of thiobarbituric acid reactive substances in plasma was decreased by RPC at 24 h post-LPS challenge. Glucose and insulin were not affected by RPC, but serum insulin concentration at 8 h was lowered by RPC compared to the control. Collectively, RPC had no or subtle effects on feed intake, milk yield and composition, rectal temperature, white and red blood cells, and serum glucose and insulin concentration in dairy cows challenged by LPS. However, RPC tended to decrease cortisol and decreased concentrations of haptoglobin and thiobarbituric acid reactive substances in blood following LPS challenge. Data suggest that dietary supplementation of RPC may modulate acute phase responses induced by bacterial infection in lactating dairy cows.

Highly pathogenic porcine reproductive and respiratory syndrome virus infection and induction of apoptosis in bone marrow cells of infected piglets

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) has been shown to have a wide range of tissue tropism, and can directly and indirectly induce cellular apoptosis. However, the impact of HP-PRRSV infection on the bone marrow (BM) of piglets remains unclear. In this study, we investigated the BM as a novel site of infection by the HP-PRRSV strain in piglets. HP-PRRSV infected SWC3+SWC8- cells in the BM and induced BM cells to undergo apoptosis. The number of apoptotic cells highlights the striking effects of HP-PRRSV on the central immune organs (BM and thymus) that may enhance the susceptibility of pigs to secondary infections and lead to high mortality. This study is, to the best of our knowledge, the first to report the impact of HP-PRRSV on the BM and implicate the depletion of BM cells during HP-PRRSV infection in the development of immunosuppression in this disease.

Effects of Direct-fed Microbial and Pine Cone Extract on Carcass Traits and Meat Quality of Hanwoo (Korean Native Cattle)

The carcass traits and meat quality of Hanwoo (Korean native cattle) whose diets were supplemented with direct-fed microbial (DFM) and pine cone extract (PCE) were evaluated. Twenty head of Hanwoo steers were divided equally into four groups and for a period of 6 months were given different diets: One group was fed a basal diet as control (CON), the other three groups were fed a basal diet supplemented with DFM-1%, DFM+PCE-1% and DFM+PEC-3%, respectively. DFM+PCE3% diet resulted the lowest carcass quality grade. The loins of DFM-1% contained higher moisture and lower fat than did the loins from the CON group. The crude protein content of DFM+PCE-3% group was significantly higher than that of the other groups. The water holding capacity and Warner-Bratzler shear force of the DFM+PCE-1% and 3% groups were lower than those of the CON and DFM-1% groups. The DFM-1% and 3% groups contained lower saturated fatty acid, higher unsaturated fatty acid, mono-unsaturated fatty acid, and poly-unsaturated fatty acid than did CON and DFM+PCE 1% group. Moreover, the n6:n3 ratios of DFM-1% and DFM+PCE-1% and 3% groups were slightly lower than that of the CON group. Thus we concluded that DFM and PCE supplementation resulted healthier Hanwoo beef with lower fat content and n6:n3 ratio.