Cromolyn-mediated improvement of intestinal barrier function is associated with enhanced piglet performance after weaning.

BACKGROUND: Previous work showed that weaning stress causes gut barrier dysfunction partly by triggering the release of corticotropin releasing factor (CRF) and thereby inducing the degranulation of intestinal mast cell (MC). This study investigated the hypothesis that attenuating the weaning-induced activation of the CRF-MC axis via administration of a MC stabilizing agent (cromolyn) may improve gut permeability and piglet performance after weaning. RESULTS: To test the hypothesis twenty piglets were weaned (20 ± 1.0 d of age; 6.4 ± 0.4 kg of BW) and injected intraperitoneally with saline (control, n = 10) or 20 mg/kg BW of sodium cromolyn (cromolyn, n = 10) at - 0.5, 8 and 16 h relative to weaning. Piglets were housed individually and fed ad libitum a pre-starter diet from one to 15 d post-weaning followed by a starter diet until the end of the study on d 36. Cromolyn improved intestinal permeability as indicated by the reduced recovery of cobalt and mannitol in plasma samples. Cromolyn treated pigs consumed more feed (369 vs. 313 g/d; P < 0.009), gained more BW (283 vs. 238 g/d; P < 0.006), and grew more efficiently (0.60 vs. 0.40; P < 0.042) than their control counterparts. As a result, cromolyn treated pigs were 1.4 kg heavier than those in the control group by d 36 after weaning (16.5 vs. 17.9 kg; P < 0.002). CONCLUSIONS: In agreement with our hypothesis, present data indicate that the cromolyn-mediated improvement of intestinal permeability is associated with enhanced pig performance after weaning.

Bile acids induce glucagon-like peptide 2 secretion with limited effects on intestinal adaptation in early weaned pigs.

Early weaning is a stressful event characterized by a transient period of intestinal atrophy that may be mediated by reduced secretion of glucagon-like peptide (GLP) 2. We tested whether enterally fed bile acids or plant sterols could increase nutrient-dependent GLP-2 secretion and improve intestinal adaptation in weanling pigs. During the first 6 d after weaning, piglets were intragastrically infused once daily with either deionized water (control), chenodeoxycholic acid (CDC; 60 mg/kg body weight), or ß-sitoesterol (BSE; 100 mg/kg body weight). Infusing CDC increased plasma GLP-2 (P < 0.05) but did not affect plasma GLP-1 and feed intake. The intestinal expression of glucagon-like peptide 2 receptor, sodium-dependent bile acid transporter, farnesoid X receptor, and guanosine protein-coupled bile acid receptor genes were not affected by CDC treatment. The intragastric administration of CDC did not alter the weight and length of the intestine, yet increased the activation of caspase-3 in ileal villi (P < 0.02) and the expression of interleukin 6 (P < 0.002) in the jejunum. In contrast, infusing BSE did not affect any of the variables that were measured. Our results show that the enteral administration of the bile acid CDC potentiates the nutrient-induced secretion of endogenous GLP-2 in early-weaned pigs. Bile acid-enhanced release of GLP-2, however, did not result in improved intestinal growth, morphology, or inflammation during the postweaning degenerative phase.

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.

Potential of Oral Nanoparticles Containing Cytokines as Intestinal Mucosal Immunostimulants in Pigs: A Pilot Study.

Antimicrobial resistance is a global threat that is worryingly rising in the livestock sector. Among the proposed strategies, immunostimulant development appears an interesting approach to increase animal resilience at critical production points. The use of nanoparticles based on cytokine aggregates, called inclusion bodies (IBs), has been demonstrated as a new source of immunostimulants in aquaculture. Aiming to go a step further, the objective of this study was to produce cytokine nanoparticles using a food-grade microorganism and to test their applicability to stimulate intestinal mucosa in swine. Four cytokines (IL-1ß, IL-6, IL-8, and TNF-α) involved in inflammatory response were produced recombinantly in Lactococcus lactis in the form of protein nanoparticles (IBs). They were able to stimulate inflammatory responses in a porcine enterocyte cell line (IPEC-J2) and alveolar macrophages, maintaining high stability at low pH and high temperature. In addition, an in vivo assay was conducted involving 20 piglets housed individually as a preliminary exploration of the potential effects of IL-1ß nanoparticles in piglet intestinal mucosa after a 7 d oral administration. The treated animals tended to have greater levels of TNF-α in the blood, indicating that the tested dose of nanoparticles tended to generate an inflammatory response in the animals. Whether this response is sufficient to increase animal resilience needs further evaluation.

Olive oil cake extract stabilizes the physiological condition of lipopolysaccharide-challenged piglets by reducing oxidative stress and inflammatory responses and modulating the ileal microbiome.

Olives are a rich source of compounds with antioxidant and anti-inflammatory activities. This study was designed to investigate whether a standardized olive cake extract was able to alleviate oxidative stress, inflammation and intestinal villus damage in a model of lipopolysaccharide (LPS)-challenged piglets. Thirty weaned piglets (6.9 ± 0.9 kg) were assigned to five groups using a randomized complete block design. Piglets were fed a basal diet before intraperitoneal (i.p.) injection of physiological saline (C); fed a basal diet alone (CL) or fed a basal diet plus an olive cake extract (OL), antibiotics (AL), or olive cake extract plus antibiotics (OAL) before i.p. injection of LPS. The feeding period lasted for 2 weeks. Piglets were euthanized 4 h after the LPS injection. Systemic oxidative and inflammatory status and intestinal morphology were evaluated. LPS challenge significantly lowered the serum levels of GSH-Px, SOD and ALB and increased the serum concentration of MDA, NO, LDH, ALT, AST, TNF-α, IL-6, DAO and D-xylose (P < 0.05), as extracted from the comparison of piglets in the C and CL groups. Intestinal morphology was altered in the duodenum and ileum, displaying that the CL group had significantly lower villus height (VH), higher crypt depth (CD) and lower VH/CD compared with the control group (P < 0.05). Moreover, feed supplementation was able to partially mitigate the negative effects of LPS challenge in all groups (OL, AL, and OAL), as evidenced by the significantly increased serum levels of GSH-Px, SOD, ALB and IL-10 and decreased concentration of MDA, NO, LDH, ALT, AST, TNF-α, IL-6, DAO and D-xylose, compared with the CL group (P < 0.05). Alterations in intestinal morphology were also prevented and the OL, AL, and OAL groups had significantly lower CD and higher VH/CD compared with the CL group (P < 0.05), both in the ileum and duodenum. Furthermore, the positive effect in the relative abundance of intestinal Lactobacillus and Clostridium at the genus level was also observed for the OL group compared to the CL group. In summary, dietary supplementation with an olive cake extract stabilized the physiological condition of piglets subjected to an acute LPS challenge by reducing oxidative stress and the inflammatory status, improving intestinal morphology and increasing the abundance of beneficial intestinal bacteria. This trial was registered at Zhejiang University (http://www.lac.zju.edu.cn) as No. ZJU20170529.

Chicken or the Egg: The Reciprocal Association Between Feeding Behavior and Animal Welfare and Their Impact on Productivity in Dairy Cows.

Feeding behavior in dairy cattle has a significant impact on feed efficiency, which is important for increasing the profitability of livestock and, at the same time, reducing the environmental impact. Feeding behavior can be measured by feeding time, meal duration, meal frequency, feeding rate, and rumination time. Higher feed intake is related to lower feed efficiency; whereas, an increase in feeding time facilitates chewing, reduces feed particle size and increases its digestibility. More frequent and shorter meals are usually associated with a more efficient use of feed due to improvement of feed digestibility. Rumination time is positively associated with milk production. Impaired health is associated with variations in feeding behavior, which can be used to identify and predict some diseases such as ketosis, mastitis, or lameness. Changes in rumination time are also a reliable indicator of mastitis, lameness, ketosis, abomasal displacement, and the onset of calving. In addition to the cause-effect relationship between disease and changes in feeding behavior, there are also some cases in which changes in feeding behavior may lead to an increased risk of disease, as exemplified by the relationship of feeding rate with sub-acute ruminal acidosis. Feeding behavior is regulated by internal and external factors and some of them are relevant for animal welfare. The main welfare-associated factors influencing feeding behavior are social behavior and temperament, and environmental effects. Cattle are social animals and hierarchy has a notable impact on feeding behavior, especially when access to feed is limited. Competition for feed causes a reduction in the average feeding time but increases feeding rate. Excitable animals visit the feeder more often and spend less time per meal. High environmental temperature affects feeding behavior, as heat-stressed cattle change their feeding pattern by concentrating the feeding events in crepuscular hours, leading to an increased risk of sub-acute ruminal acidosis. In conclusion, feeding behavior is a determinant feature for improving efficiency, productivity and welfare of dairy cattle. Routine assessment of feeding behavior allows monitoring of health and production status of dairy cattle at the individual and farm level, which is a useful tool to optimize the management of livestock.