Effects of dietary oregano essential oil and vitamin E supplementation on meat quality, stress response and intestinal morphology in pigs following transport stress

N-Carbamylglutamate in ovo feeding improves carcass yield, muscle fiber development, and meat quality in broiler chickens

BACKGROUND

Insufficient endogenous nutrients in the broiler embryo can lead to muscle gluconeogenesis, which ultimately affects the post-hatching performance of chicks. This study investigated the effects of in ovo feeding (IOF) of N-carbamylglutamate (NCG) on the growth hormones, carcass yield, and meat quality in broilers. Fertile eggs from a 30-week-old Ross 308 breeder flock were divided into three treatment groups: NC (non-injection), SC (100 μL saline-injection), and NCG (2 mg NCG injection). Each group had six replicates, with 70 eggs per replicate during incubation. Injections were administered on the 17.5th day of embryonic development. After hatching, 270 chicks were selected for 42-day rearing for further sampling.

RESULTS

Chicks in the NCG group had significantly higher body weight (BW) and average daily gain (ADG) at the growing phase, increased growth and testosterone hormone in both feeding phases (21 and 42 days), and improved average daily gain (ADG) and food conversion ratio (FCR) in both grower and entire feeding phases (P < 0.05). Triiodothyronine (T3) and tetraiodothyronine (T4) levels, carcass yield, dressing, drum weight, breast muscle weight, drumstick weights, thighs, pectoralis major, and their part percentage of carcass were improved in the NCG group (P < 0.05), these effects were varied along feeding phases. Moreover, IOF of the NCG also improved pectoralis breast muscle color values at 24 h post mortem (P < 0.05).

CONCLUSION

These results suggest that NCG injection at the late embryonic age of broiler enhances growth performance and meat quality throughout the lifespan and this can probably be attributed to an increase in thyroid and testosterone hormones, indicating potential involvement in metabolic and nutrient partitioning pathway regulation. © 2024 Society of Chemical Industry.

Phytogenic feed additives as natural antibiotic alternatives in animal health and production: A review of the literature of the last decade

The use of antibiotics in animal production raises great public safety concerns; therefore, there is an urgent need for the development of substitutes for antibiotics. In recent decades, plant-derived feed additives have been widely investigated as antibiotic alternatives for use in animal health and production because they exert multiple biological functions and are less likely to induce resistance development. This review summarizes the research history and classification of phytogenic feed additives and their main functions, potential modes of action, influencing factors, and potential negative effects. Further, we highlight the challenges in developing sustainable, safe, and affordable plant-derived antibiotic alternatives for use in livestock production.

The Role of Vitamins in Mitigating the Effects of Various Stress Factors in Pigs Breeding

Good practices in farm animal care are crucial for upholding animal well-being, efficiency, and health. Pigs, like other farm animals, are exposed to various stressors, including environmental, nutritional, chemical, psychological, physiological, and metabolic stressors, which can disrupt their internal balance and compromise their well-being. Oxidative stress can adversely affect animal performance, fertility, and immunity, leading to economic losses for farmers. Dietary considerations are hugely important in attaining these objectives. This paper reviews studies investigating the impact of additional vitamin supplementation on stress reduction in pigs. Vitamin A can be beneficial in counteracting viral and parasitic threats. Vitamin B can be a potential solution for reproductive issues, but it might also be beneficial in reducing the effects of inappropriate nutrition. Vitamin C plays a vital role in reducing the effects of heat stress or exposure to toxins in pigs. Vitamin D proves to be beneficial in addressing stress induced mostly by infections and weaning, while vitamin E has been shown to mitigate the effects of toxins, heat stress, or transport stress. This review highlights the potential benefits of these dietary antioxidants in maintaining pig health, enhancing productivity, and counteracting the adverse effects of various stressors. Understanding the role of vitamins in pig nutrition and stress management is vital for optimising farm animal welfare and production efficiency.

The Genetic Selection of HSPD1 and HSPE1 Reduce Inflammation of Liver and Spleen While Restraining the Growth and Development of Skeletal Muscle in Wuzhishan Pigs

Wuzhishan (WZS) pigs, which are minipigs native to Hainan Province in China, are characterized by strong resistance to extreme hot temperatures and humidity. The relationship between their immune response and growth still needs to be clarified. In this study, we used whole genome sequencing (WGS) to detect variations within 37 WZS pigs, 32 Large White (LW) pigs, and 22 Xiangxi black (XXB) pigs, and ~2.49 GB of SNPs were obtained. These data were combined with those of two other pig breeds, and it was found that most of the genes detected (354) were located within the distinct genetic regions between WZS pigs and LW pigs. The network that was constructed using these genes represented a center including 12 hub genes, five of which had structural variations (SVs) within their regulatory regions. Furthermore, RNA-seq and RT-qPCR data for 12 genes were primarily consistent in liver, spleen, and LDM tissues. Notably, the expression of HSPs (HSPD1 and HSPE1) was higher while that of most genes involved in the JAK3-STAT pathway were lower in liver tissue of WZS pigs, compared with LW pigs. This likely not only reduced inflammation-related immune response but also impaired their growth. Our findings demonstrated the role of HSPs in the connection between inflammation and growth rate, while also providing the fundamental genetic selection of the adaptability of WZS pigs.

Nano vitamin E improved the antioxidant capacity of broiler chickens

Vitamin E (VE) is a potent nutritional antioxidant that is critical in alleviating poultry oxidative stress. However, the hydrophobic nature and limited stability of VE restrict its effective utilization. Nanotechnology offers a promising approach to enhance the bioavailability of lipophilic vitamins. The objective of this experiment was to investigate the effects of different sources and addition levels of VE on the growth performance, antioxidant capacity, VE absorption site, and pharmacokinetics of Arbor Acres (AA) broilers. Three hundred and eighty-four 1-d-old AA chicks were randomly allocated into four groups supplemented with 30 and 75 IU/kg VE as regular or nano. The results showed that dietary VE sources had no significant impact on broiler growth performance. However, chickens fed 30 IU/kg VE had a higher average daily gain at 22 to 42 d and 1 to 42 d, and lower feed conversion ratio at 22 to 42 d than 75 IU/kg VE (P < 0.05). Under normal feeding conditions, broilers fed nano VE (NVE) displayed significantly higher superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) enzyme activities and lower malonic dialdehyde (MDA) concentration (P < 0.05). Similarly, NVE had a higher antioxidant effect in the dexamethasone-constructed oxidative stress model. It was found that nanosizing technology had no significant effect on the absorption of VE in the intestinal tract by examining the concentration of VE in the intestinal tract (P > 0.05). However, compared to broilers perfused with regular VE (RVE), the NVE group displayed notably higher absorption rates at 11.5 and 14.5 h (P < 0.05). Additionally, broilers perfused with NVE showed a significant increase in the area under the concentration versus time curve from zero to infinity (AUC0-∞), mean residence time (MRT0-∞), elimination half-life (t1/2z), and peak concentration (Cmax) of VE in plasma (P < 0.05). In summary, nanotechnology provides more effective absorption and persistence of VE in the blood circulation for broilers, which is conducive to the function of VE and further improves the antioxidant performance of broilers.

Oregano Essential Oil and Purple Garlic Powder Effects on Intestinal Health, Microbiota Indicators and Antimicrobial Resistance as Feed Additives in Weaning Piglets

Finding alternatives to zinc oxide is a pressing issue for the pig production sector. We studied the impact of the bioactive components degradation of oregano essential oil (OEO) and purple garlic powder (PGP) during storage in silos, their effect on the morphometry of the jejunum and ileum and the cecal microbiota as intestinal health indicators in piglets during the post-weaning period. We also monitored antimicrobial resistance in the commensal indicator E. coli. Histological parameters and intestinal microbiota were measured in 140 piglets weaned at 21 days of age. Seven dietary treatments were used: a negative control group (basal diet), a positive control group with ZnO (3000 mg/kg of food), two groups with OEO at 0.4% and 1.2%, respectively, two groups with PGP 0.4% and 2%, respectively, and a group with OEO with 1.2% combined with PGP with 2%. Each group of piglets received the treatment for seven weeks, from weaning, before samples were taken. Antibiotic resistance profiles were measured in 81 E. coli strains. On this occasion, only the control groups, ZnO, OEO 1.2%, PGP 2% and OEO 1.2% + PGP 2% were used, and the samples were obtained from the cecal content. A progressive loss of the bioactive components of OEO and PGP was observed during the 34 days of storage (p < 0.05). PGP 2%, OEO 1.2% and their combination showed results similar to ZnO (p > 0.05), or superior in the study of intestinal morphometry and the values of E. coli and Lactobacillus. All categories showed high levels of resistance. Only the strains isolated from the OEO 1.2% group did not show resistance to colistin and presented the lowest resistance values. In general, high doses of the additives studied showed the best results, obtaining levels like or higher than those offered by ZnO.

Effect of dietary oregano essential oil and milk replacer on physiological status and immunological responses of pre- and post-weaned Ghoongroo piglets

Ghoongroo pigs have good adaptability in a low input production system with high prolificacy. The present study was conducted on pre-and post-weaned Ghoongroo piglets from 2-3 days to 12 weeks of age to evaluate the effect of a milk replacer and oregano essential oil (EO) on growth, physiological and immunological responses. Thirty six piglets were randomly divided into three groups. The control group (n = 12) was allowed to suck mother's milk. Second group piglets were provided milk replacer (MR) and piglets of the third group were provided milk replacer along with oregano EO at 500 mg/kg diet. After weaning, piglets were provided standard concentrate diets. The results showed that the body weight in MR and MR + EO groups were significantly higher compared with the control. The MR + EO group had better intestinal microbiota, greater nonspecific innate immunity with the phagocytosis efficacy of neutrophils, lower cortisol concentration and more stable thyroid hormones than the other groups. The better haematological status supported the rapid organ development and improved intestinal health status in both the experimental groups. In conclusion, milk replacer, especially with the inclusion of oregano EO, can lower weaning stress, enhance nonspecific immunity and improve growth and health status of piglets.

Dietary oregano essential oil supplementation alters meat quality, oxidative stability, and fatty acid profiles of beef cattle

This study was conducted to elucidate the effects of oregano essential oil (OEO) supplementation on the meat quality, antioxidant capacity, and nutritional value of the longissimus thoracis muscle in steers. Steers were divided into three groups (n = 9) and fed either a basal diet, or a basal diet supplemented with 130 mg/d OEO, or 230 mg/d OEO for 390 days. The results demonstrated that dietary OEO supplementation increased the total antioxidant capacity and activity of catalase, glutathione peroxidase, and superoxide dismutase, and decreased pH30min, pH24h, cooking loss, and malondialdehyde content. OEO increased the concentrations of polyunsaturated fatty acids and conjugated linoleic acid. In contrast, saturated fatty acids decreased, accompanied by increased essential amino acids, flavor amino acids, and total amino acids in the longissimus thoracis muscle. In summary, dietary OEO supplementation promotes the nutritional and meat quality of beef by maintaining its water-holding capacity and meat color, enhancing its antioxidative capacity, and preventing lipid oxidation.

Effects of different amino acid levels and a carvacrol-thymol blend on growth performance and intestinal health of weaned pigs

Background

Over the past years, antibiotic growth promoter had been restricted in animal husbandry production in many countries because of antimicrobial resistance and foodborne antibiotic residues. However, the problems of poor intestinal health and low growth efficiency of piglets have not been solved completely in an antibiotic-free diet, and it is urgent to explore alternatives to antimicrobial growth promoters.

Methods

Here, a total of 532 weaned pigs were assigned to one of 4 treatments, the low amino acid (AA) level diet (d 1 to d 14 is 1.35%, d 15 to d 42 is 1.25%) (Low AA), the low AA level diet supplementation with a carvacrol–thymol blend (50 mg carvacrol and 50 mg thymol/kg of diet) (CB) (Low AA+CB), the high AA level diet (d 1 to d 14 is 1.50%, d 15 to d 42 is 1.40%) (High AA), and the high AA level diet supplementation with a CB (High AA+CB), respectively. Then we measured growth performance and intestinal health indicators of weaned pigs.

Results

Results showed that high AA level significantly reduced plasma urea nitrogen, plasma Interleukin-6 (IL-6) and fecal lipocalin-2 contents (P <  0.05), significantly increased the relative abundance of fecal Lactobacillus and Enterococcus, and had a trend to increase the fecal secretory immunoglobulin A (sIgA) and mucin 2 (MUC 2) contents (P <  0.05) in piglets, thereby alleviating the diarrhea of piglets and reducing the feed conversion ratio (FCR) of piglets during d 1~14 after weaning. Dietary supplementation with CB significantly increased the activity of plasma antioxidant enzymes T-SOD and GSH-px (P <  0.05), while significantly reduced plasma malondialdehyde (MDA), plasma interleukin-1β (IL-1β), plasma endotoxin and D-lactic acid contents (P <  0.05). Meanwhile, CB significantly decreased fecal lipocalin-2 contents and the abundance of fecal Escherichia coli (P < 0.05). Thus, we hypothesis that dietary supplementation with CB significantly increased the average daily gain (ADG) of piglets (P < 0.05) during d 1~14 after weaning through promoting intestinal health.

Conclusion

These results suggest that high AA level and dietary supplementation with CB improved the growth performance of weaned pigs in an antibiotic-free diet by improving AA metabolism and intestinal antioxidant capacity.

Effects of dietary plant essential oil supplementation on growth performance, nutrient digestibility and meat quality in finishing pigs

This study was aimed to explore the effects of dietary plant essential oil (PEO) supplementation on growth performance and meat quality in finishing pigs. A total of eighteen Duroc × Landrace × Yorkshire finishing barrows with an average initial body weight of 79.86 ± 1.94 kg were randomly assigned to CON group (fed with a basal diet) and PEO group (fed with the basal diet containing 200 mg/kg PEO) with 9 replicates per treatment. The trial lasted for 42 days. The results showed that dietary PEO supplementation significantly increased ADG during phase I (1-21 days) and the overall experimental period (p < 0.05), tended to increase ADFI in phase II (22-42 days) and the overall experimental period (p = 0.09), decreased F/G in phase I (p < 0.05) and tended to decrease F/G during the overall experimental period (p = 0.08). Meanwhile, compared to the CON group, the digestibility of DM, GE and EE in the PEO group was improved remarkably (p < 0.05). PEO supplementation also significantly improved T-AOC and lowered MDA content in longissimus dorsi (p < 0.05), tended to increase the activity of T-SOD (p = 0.06). A higher IMF content (p = 0.09) and a lower shear force (p = 0.08) of longissimus dorsi were found in the PEO group than that in CON group (p = 0.09). Furthermore, pigs fed the PEO diet showed higher mRNA abundances of GLUT4, LPL, CPT-1, CD36, FABP and LDL-R in the liver, and GLUT4 and FAS in the longissimus dorsi (p < 0.05). In conclusion, PEO fed to finishing pigs improved the growth performance and nutrient digestibility. Furthermore, PEO supplementation had the potential role to improve pork quality by increasing the antioxidant capacity and IMF content, and decreasing the shear force of longissimus dorsi to a certain extent.

Potential improvements of the cognition of piglets through a synbiotic supplementation from 1 to 28 days via the gut microbiota

The influence of feed supplements on behavior and memory has been recently studied in livestock. The objectives of the study were to evaluate the effects of a synbiotic on: an episodic-like (SOR: Spontaneous Object Recognition), a working (BARR: Fence barrier task), a long-term (TMAZE: Spatial T-maze task) memory test and on gut microbiota composition. Eighteen female piglets were supplemented from 1 to 28 days of age with a synbiotic (SYN), while 17 served as control (CTL). Feces were collected on days 16, 33 and 41 for 16S rRNA gene composition analyses. In the SOR, SYN piglets interacted more quickly with the novel object than CTL piglets. In the BARR, SYN piglets had shorter distances to finish the test in trial 3. In the TMAZE, SYN piglets were quicker to succeed on specific days and tended to try the new rewarded arm earlier during the reversal stage. Difference of microbiota composition between treatments was nonexistent on D16, a tendency on D33 and significant on D41. The synbiotic supplement may confer memory advantages in different cognitive tasks, regardless of the nature of the reward and the memory request. Difference in memory abilities can potentially be explained by differences in microbiota composition.

Plant Feed Additives as Natural Alternatives to the Use of Synthetic Antioxidant Vitamins on Livestock Mammals' Performances, Health, and Oxidative Status: A Review of the Literature in the Last 20 Years

In the last two decades, the interest in natural plant feed additives (PFA) as alternatives to synthetic vitamins in livestock nutrition has increased. After a systematic review, a total of 19 peer-reviewed papers published between 2000 and 2020 were retained to evaluate the antioxidant effects of PFA compared to synthetic antioxidant vitamins (mainly vitamin E; VitE) in livestock nutrition. These studies demonstrated that PFAs could be as efficient as VitE in counteracting oxidative stress in pigs, rabbits, and ruminants. However, PFAs only positively affected animals’ growth performance and feed efficiency in some monogastric studies. The PFA can affect antioxidant enzyme activity in a dose- and method of administration-dependent manner. The antioxidant capacity of both PFA and VitE were depressed in cows fed with diets rich in polyunsaturated fatty acids. Variability among studies could be related to species differences. Despite the interest of the feed industry sector in PFA, there are still very few studies evaluating their antioxidant effect in species other than poultry.

Transport stress affects the fecal microbiota in healthy donkeys

Background

With the development of large‐scale donkey farming in China, long‐distance transportation has become common practice, and the incidence of intestinal diseases after transportation has increased. The intestinal microbiota is important in health and disease, and whether or not transportation disturbs the intestinal microbiota in donkeys has not been investigated.

Objectives

To determine the effects of transportation on the fecal microbiota of healthy donkeys using 16S rRNA sequencing.

Animals

Fecal and blood samples were collected from 12 Dezhou donkeys before and after transportation.

Methods

Prospective controlled study. Cortisol, ACTH, and heat‐shock protein 90 (HSP90) concentrations were measured. Sequencing of 16S rRNA was used to assess the microbial composition. Alpha diversity and beta diversity were assessed.

Results

Results showed significant (P < .05) increases in cortisol (58.1 ± 14.6 to 71.1 ± 9.60 ng/mL), ACTH (163.8 ± 31.9 to 315.8 ± 27.9 pg/mL), and HSP90 (10.8 ± 1.67 to 14.6 ± 1.75 ng/mL) on the day of arrival. A significantly lower (P = .04) level of bacterial richness was found in fecal samples after transportation, compared with that before transportation without distinct changes in diversity. Most notably, donkeys had significant decreases in Atopostipes, Eubacterium, Streptococcus, and Coriobacteriaceae.

Conclusions and Clinical Importance

Transportation can induce stress in healthy donkeys and have some effect on the composition of the in fecal microbiota. Additional studies are required to understand the potential effect of these microbiota changes, especially significantly decreased bacteria, on the development intestinal diseases in donkeys during recovery from transportation.

Plant Feed Additives as Natural Alternatives to the Use of Synthetic Antioxidant Vitamins in Livestock Animal Products Yield, Quality, and Oxidative Status: A Review

The interest for safe and natural foods of animal origin is currently increasing the use of plant feed additives (PFA) as antioxidants in animal nutrition. However, studies with livestock animals dealing with PFA as antioxidants are scarce. The aim of the present review was to evaluate the antioxidant impact of PFA compared with synthetic vitamins on animal food product yield and quality. For this purpose, peer-reviewed studies published between 2000 and 2020 were collected. Most papers were carried out on ruminants (n = 13), but PFA were also tested in swine (n = 6) and rabbits (n = 2). The inclusion of PFA in the diets of pigs, rabbits, and ruminants improved the products’ quality (including organoleptic characteristics and fatty acids profile), oxidative stability, and shelf life, with some impacts also on their yields. The effects of PFA are diverse but often comparable to those of the synthetic antioxidant vitamin E, suggesting their potential as an alternative to this vitamin within the diet.

Differential Effects of Dietary Oregano Essential Oil on the Inflammation Related Gene Expression in Peripheral Blood Mononuclear Cells From Outdoor and Indoor Reared Pigs

Intensive farming systems represent a stressful environment for pigs and negatively influence neuroendocrine functions, behavior, and performance. Outdoor farming is an alternative option, which is thought to imply several beneficial effects for the animal. Dietary essential oils are known to be an innovative strategy to improve pig health and performance, and oregano essential oil (ORE) possesses beneficial effects due to its antimicrobial, anti-fungal, and antioxidant properties. We tested the effect of dietary ORE on peripheral blood mononuclear cells (PBMCs) in 36 growing pigs, either reared under indoor or outdoor conditions. Quantitative real-time PCR (RT-qPCR) assay was used to evaluate the effect of diet (control vs. ORE) and the time of sampling (T1-120 days vs. T2-190 days) on the expression of inflammatory and immune-related genes (TNF, IL1β, IL8, IL18, IL10, IL1RN, STAT3, HSP90, ICAM-1, and NFKB1). Under outdoor condition, the majority of transcripts were upregulated (p < 0.05), assuming a general inflammatory status (TNF, HSP90, NFKB1, IL1β, and STAT3). However, an interaction between diet and the farming system was observed: HSP90, NFKB1, and STAT3 were downregulated (p < 0.05) in the outdoor reared pigs when fed the ORE diet. Our study showed that bioactive compounds of ORE exert their activity, especially when the animals are exposed to stressful stimuli. Dietary ORE can be an acceptable strategy to help pigs tolerate the stress related to the harsh, outdoor, rearing conditions.

Transport to the Slaughterhouse Affects the Salmonella Shedding and Modifies the Fecal Microbiota of Finishing Pigs

Contaminated pork is a significant source of foodborne Salmonellosis. Pork is contaminated at the slaughterhouse and the intestinal content is the predominant source of Salmonella for carcass contamination. The prevalence of Salmonella-positive pigs increases significantly when the time of transport to the slaughterhouse is longer than two hours. The hypothesis behind this study is that transport to the slaughterhouse increases the load of Salmonella in feces and determines a shift of the fecal microbiota in finishing pigs. Fecal samples were collected in a pig herd positive for Salmonella spp., the day before the transport and at the slaughterhouse. Salmonella loads were estimated by the most probable number (MPN) technique, according to the ISO/TS 6579-2:2012/A1. Moreover, the fecal bacteria composition was assessed by sequencing the V3-V4 hypervariable regions of the 16S rRNA gene. Our study showed that the load of Salmonella increases after transport, confirming that this phase of the production chain is a critical point for the control of Salmonella contamination. A lower richness and an increased beta-diversity characterized the fecal microbiota composition of Salmonella-positive animals after transport. In this stage, a natural Salmonella infection causes a disruption of the fecal microbiota as observed in challenge studies.

Effects of dietary Origanum vulgare on gilthead seabream (Sparus aurata L.) immune and antioxidant status

Origanum sp. is a very common genus of aromatic plants worldwide distributed around the Mediterranean area and O. vulgare (oregano) is the most important species of this genus throughout the world. Due the known medicinal properties of oregano, the effect of diets enriched with 0% (control), 0.5% and 1% oregano leaves powder was studied on the growth, immune and antioxidant status of gilthead seabream (Sparus aurata L.). Fish fed with oregano 0.5% and 1% enriched diets improved both humoral (IgM and bactericidal activity in skin mucus and protease activity in serum) and cellular (head kidney leucocytes phagocytic ability) immunity at 15 and 30 days. Furthermore, the addition of oregano did not provoke any significant effect neither in the growth promotion nor in the liver antioxidant enzymes activity studied in the serum and skin mucus. The possibility of using O. vulgare as a functional additive to fish diet is discussed.

Effects of Three Distinct 2-Week Long Diet Strategies After Transport on Weaned Pigs' Short and Long-Term Welfare Markers, Behaviors, and Microbiota

Alternative feed supplements have shown promising effects in terms of performance, but their effects on welfare have had little evaluation. In the present study, we aimed at evaluating the effect of diet supplementation on welfare indicators. A total of 246 piglets were weaned and transported for 12 h. After transport, they were assigned to one of 3 diets for a 14-day period: A-an antibiotic diet including chlortetracycline and tiamulin, NA-a control diet without any antibiotic or feed supplement, GLN-a diet including 0.20% L-glutamine. After the 14-day period, all piglets were fed the same diet. Tear staining was measured 11 times post-weaning (from d0 to 147). Skin lesions were counted before and after weaning (d-2, 2, and 36). Novel object tests (NOT) were done in groups 4 times post-weaning (d17, 47, 85, 111). Samples for 16S rRNA gene composition were collected prior to transport (d0), following the 14-day period (d14) and at the conclusion of the nursery phase (d34). The NA pigs appeared less interested in novel objects. On d17, they avoided the object less than A pigs (P < 0.05). They spent less time exploring the object on d85 and took longer to interact with the object on d111 than A and GLN pigs (P < 0.05). NA pigs also appeared more sensitive to environment and management. They had larger tear stains than GLN pigs on d84 and 110 (P < 0.05). On d2, NA pigs had more lesions than A and GLN (P < 0.01). In terms of microbiota composition, GLN had higher α-diversity than A and NA (P < 0.001). Differences between dietary treatments were absent at d0, were demonstrated at d14 and disappeared at d34. Pearson correlations between aggression, stress and anxiety indicators and bacterial populations were medium to high from 0.31 to 0.69. The results demonstrate that short-term feeding strategy can have both short- and long-term effects on behavior and welfare, that may partly be explained by changes in gut microbiota composition. Supplementation with GLN appears to confer similar benefits to dietary antibiotics and thus could be a viable alternative.

Changes in saliva proteins in two conditions of compromised welfare in pigs: An experimental induced stress by nose snaring and lameness

The aim of this study was to identify biological pathways and proteins differentially expressed in saliva of pigs in two conditions of compromised welfare: an acute stress consisting of restraint with a nose snare and in pigs with lameness which is a highly frequent problem in the swine industry. For this purpose, high-resolution quantitative proteomics based on Tandem Mass Tags labelling was used. Four proteins showed significant differences in the conditions of compromised welfare, namely cornulin, the heat shock protein 27 and lactate dehydrogenase (LDH), that showed significant increases, whereas immunoglobulin J chain showed a significant decrease. LDH, which was the protein that showed the highest differences, was selected for validation and clinical evaluation as a diagnostic biomarker. Significant changes in this protein were observed between pigs restrained with a nose snare and pigs with lameness compared with healthy pigs when measured with available commercial assays in a larger population of pigs. In conclusion, this study reports that in situations of compromised welfare on farm, such as acute stress and lameness in pigs, there are changes in proteins and metabolic pathways in saliva, and describes a series of proteins that could potentially be used as biomarkers for both short term acute stress and longer term chronic stress of lameness. These biomarkers would have the advantage of being measured in saliva by a noninvasive and not stressful collection sampling procedure.

A neglected fish stressor: mechanical disturbance during transportation impacts susceptibility to disease in a globally important ornamental fish

The transport of fish in aquaculture and the ornamental trade exposes fish to multiple stressors that can cause mass mortalities and economic loss. Previous research on fish transport has largely focussed on chemical stress related to deterioration in water quality. However, mechanical disturbance during routine fish transport is unpredictable and is a neglected potential stressor when studying fish welfare. Stress-induced immunosuppression caused by mechanical disturbance can increase the chances of contracting infections and can significantly increase infection burden. Here, using a model host-parasite system (guppy Poecilia reticulata and the monogenean ectoparasite Gyrodactylus turnbulli) and a new method of bagging fish (Breathing Bags™), which reduces mechanical disturbance during fish transport, we investigated how parasite infections contracted after simulated transport impact infection trajectories on a globally important ornamental freshwater species. Guppies exposed to mechanical transport disturbance suffered significantly higher parasite burden compared to fish that did not experience transport disturbance. Unfortunately, there was no significant reduction in parasite burden of fish transported in the Breathing Bags™ compared to standard polythene carrier bags. Thus, transport-induced mechanical disturbance, hitherto neglected as a stressor, can be detrimental to disease resistance and highlights the need for specific management procedures to reduce the impact of infectious diseases following routine fish transport.

Effects of feeding diets containing essential oils and betaine to heat-stressed growing-finishing pigs

This study was to evaluate the effects of dietary essential oils (EO) and betaine on growth performance, nutrient digestibility and serum hormones in growing-finishing pigs under heat stress conditions. A total of 96 crossed pigs [(Landrace × Yorkshire) × Duroc] with an initial body weight (BW) of 24.7 ± 0.27 kg were used in an 18-week trial. Pigs were randomly allocated to four treatments according to BW and gender. There were six replication pens in each treatment, with four pigs (two barrows and two gilts) per pen. Treatment groups were: (1) control group (CON), basal diet + 23°C for 24 h; (2) heat stress group (HC) with basal diet + 37°C for 9 h, 23°C for 15 h; (3) group HEO, HC with 0.01% EO; (4) group HBE, HC with 0.1% betaine. During the overall period, groups HEO and HBE had higher (p < 0.05) average daily gain than group HC. At week 6, group HC had a lower apparent total tract digestibility (ATTD) of dry matter (DM) (p < 0.05), but at week 12, this group had lower ATTD of DM, nitrogen and gross energy than group HEO (p < 0.05). At week 12 and 18, dietary EO decreased (p < 0.05) serum cortisol and norepinephrine concentration. At week 18, dietary EO and betaine decreased (p < 0.05) epinephrine concentration. Conclusively, dietary EO may be a potential nutritional strategy to alleviate heat stress in growing-finishing pigs.

Effect of oregano essential oil and benzoic acid supplementation to a low-protein diet on meat quality, fatty acid composition, and lipid stability of longissimus thoracis muscle in pigs

BACKGROUND

Consumers are becoming increasingly interested in food containing appropriately high concentration of intramuscular fat (IMF) and polyunsaturated fatty acids (PUFA). The supplementation of feed with antioxidants decreases degradation of lipids in muscles thereby enhances nutritional and sensory properties of meat. Two experiments were conducted to determine the effects of adding oregano essential oil (OEO) and benzoic acid (BA) to low-protein, amino acid-supplemented diets on meat quality, sensory profile, fatty acid composition, and lipid oxidation of longissimus thoracis (LT) muscle in pigs.

METHODS

In Exp. 1, 21 barrows were housed in metabolism cages and randomly allotted to 1 of 3 diets. The three diets were normal protein diet (NPD), medium protein diet (MPD) and low protein diet (LPD) with 1% and 2% less than NPD, respectively. In Exp. 2, 36 barrows were randomly divided into three experimental groups, namely, NPD, LPD, and identical LPD supplemented with blends of OEO (250 mg/kg feed) and BA (1000 mg/kg feed) (LPOB) groups.

RESULTS

No significant effects of diets on meat quality were observed in Exp. 1. The b*45min, tenderness, and IMF content in LPD muscle were higher than those in NPD and LPOB muscle. The LT muscle in LPD group contained a higher percentage of oleic acid (C18:1n-9) and a lower percentage of linoleic acid (C18:2n-6) than those in NPD group. Dietary LPOB improved oxidative stability, total superoxide dismutase, and glutathione peroxidase but decreased drip loss in LT muscle.

CONCLUSIONS

These findings suggest that growing-finishing pigs fed with a low-protein, amino acid-supplemented diet show a high content of intramuscular fat in the longissimus thoracis muscle. Dietary LPOB enhances the anti-oxidative status by improving antioxidative capacity but deteriorates the sensory attributes by decreasing IMF content of meat.

Effect of oregano essential oil supplementation to a reduced-protein, amino acid-supplemented diet on meat quality, fatty acid composition, and oxidative stability of Longissimus thoracis muscle in growing-finishing pigs

This study investigated the effects of reduced-protein, amino acid-supplemented diet supplementation with oregano essential oil (OEO) in pigs, from growing period to slaughter, on the meat quality, fatty acid composition, and oxidative stability of Longissimus thoracis (LT) muscle. Thirty-six barrows were randomly divided into three experimental treatments, namely, normal protein diet (NPD), reduced-protein, amino acid-supplemented diet (RPD), and identical RPD supplemented (250mg/kg feed) with OEO (OEO) treatments. Dietary RPD and OEO increased the b*_45min, tenderness, overall acceptance, and intramuscular fat (IMF) content of pork compared with dietary NPD. The percentage of n-3 polyunsaturated fatty acid (n-3 PUFA) and the percentage of monounsaturated fatty acid in OEO muscle were higher and lower than those in RPD muscle, respectively. Dietary OEO improved oxidative stability, total antioxidative capacity, and catalase but decreased drip loss in LT muscle. Results indicated that dietary OEO enhanced the sensory attributes and anti-oxidative status of pork meat by improving IMF and n-3 PUFA proportion and antioxidative capacity.