In vitro inhibition studies of natural resin acids to Clostridium perfringens , Staphylococcus aureus and Escherichia coli O149

Effect of dietary tall oil fatty acids and hydrolysed yeast in SNP2-positive and SNP2-negative piglets challenged with F4 enterotoxigenic Escherichia coli

Reduction of post-weaning diarrhoea caused by ETEC is a principal objective in pig farming in terms of welfare benefits. This study determined the effects of genetic susceptibility and dietary strategies targeting inflammation and fimbriae adherence on F4-ETEC shedding and diarrhoea in weaned piglets in an experimental challenge model. A DNA marker test targeting single nucleotide polymorphism 2 (SNP2) identified piglets as heterozygous (SNP2+, susceptible) or homozygous (SNP2-, resistant) to developing F4ac-ETEC diarrhoea. A total of 50 piglets, 25 SNP2+ and 25 SNP2-, were weaned at 30 days of age and equally distributed to different treatments (n = 10): Positive control (PC): piglets fed with a negative control diet and provided with colistin via drinking water; Negative control (NC): piglets fed with a negative control diet; Tall oil fatty acids (TOFA): piglets fed with a negative control diet + 1.0 g TOFA/kg feed; Yeast hydrolysate (YH): piglets fed with a negative control diet + 1.5 g YH/kg feed derived from Saccharomyces cerevisiae; and Combination (COM): piglets fed with a negative control diet + 1.0 g TOFA and 1.5 g YH/kg feed. On day 10 post-weaning, all piglets were infected with F4-ETEC by oral administration. Piglets fed with PC, TOFA, YH or COM had a lower faecal shedding of F4-ETEC than NC piglets (P < 0.001), which was also shorter in duration for PC and TOFA piglets than for NC piglets (P < 0.001). Piglets in PC, TOFA, YH and COM had a shorter diarrhoea duration versus NC when classified as SNP2+ (P = 0.02). Furthermore, PC, TOFA and YH piglets grew more than NC and COM piglets in the initial post-inoculation period (P < 0.001). In addition, the level of faecal F4-ETEC shedding and the percentage of pigs that developed F4-ETEC diarrhoea (72 vs. 32%, P < 0.01) following infection were higher, and the duration of F4-ETEC diarrhoea longer (2.6 vs. 0.6 days, P < 0.001), in SNP2+ piglets than in SNP2- piglets, and led to reduced growth performance (P = 0.03). In conclusion, piglets fed with TOFA, YH or their combination, irrespective of their SNP2 status, are more resilient to F4-ETEC infection. Moreover, SNP2+ piglets show a higher level of F4-ETEC shedding and diarrhoea prevalence than SNP2- piglets, confirming an association between SNP2 and F4ac-ETEC susceptibility.

In-Feed Supplementation of Resin Acid-Enriched Composition Modulates Gut Microbiota, Improves Growth Performance, and Reduces Post-Weaning Diarrhea and Gut Inflammation in Piglets

The weaning process represents a delicate phase for piglets, and is often characterized by lower feed intake, lower weight gain, diarrhea, and ultimately increased mortality. We aimed to determine the effects of RAC supplementation in diets on improving piglet growth and vitality, reducing post-weaning diarrhea, and enhancing gut health. In a 2 × 2 × 2 factorial experiment, we selected forty sows and their piglets. Piglets were followed until seven weeks of age. There were no significant differences found between RAC treated and control piglets until weaning (p = 0.26). However, three weeks after weaning, RAC treated piglets had higher body weight and average daily growth (ADG) than the control piglets (p = 0.003). In addition, the piglets that received RAC after weaning, irrespective of mother or prior creep feed treatment, had lower post-weaning diarrhea (PWD) and fecal myeloperoxidase (MPO) level than control piglets. Gut microbiota analysis in post-weaning piglets revealed that RAC supplementation significantly increased Lachnospiraceae_unclassified, Blautia, Butyricicoccus, Gemmiger and Holdemanella, and decreased Bacteroidales_unclassified. Overall, RAC supplementation to piglets modulated post-weaning gut microbiota, improved growth performance after weaning, reduced post-weaning diarrhea and reduced fecal myeloperoxidase levels. We therefore consider RAC to be a potential natural feed supplement to prevent enteric infections and improve growth performance in weaning piglets.

Interactive effect of 2 dietary calcium and phytase levels on broilers challenged with subclinical necrotic enteritis: part 1-broiler performance, gut lesions and pH, bacterial counts, and apparent ileal digestibility

This study investigated the hypothesis that high dietary calcium (Ca) would stimulate necrotic enteritis (NE) and reduce performance, gut health, and nutrient digestibility, and if increased, phytase would reduce NE. Ross 308 male broilers (n = 768) were randomly distributed to 8 treatments in a factorial arrangement. Factors were NE challenge (no or yes), phytase level (500 or 1,500 FTU/kg using 500 FTU/kg matrix values), and Ca level (0.6 or 1.0% starter, 0.5 or 0.9% grower, 0.4 or 0.8% finisher) with the same level of available P (0.40 S, 0.35 G, and 0.35 F). There were 48 pens, 16 birds per pen and 6 replications. Half of the birds were challenged with Eimeria spp on day 9 and 10⁸ CFU per mL of Clostridium perfringens strain EHE-NE18 on day 14 and 15. Gain was higher in birds fed high phytase on day 14 (P < 0.01), day 21 (P < 0.01), day 28 (P < 0.01), and day 35 (P < 0.01). Birds fed high phytase had greater livability on day 21 (P < 0.01). Ca was more digestible in high-Ca diets on day 16, and an NE × Ca interaction (P < 0.05) showed this effect to be more pronounced in unchallenged than in challenged birds. A challenge × Ca interaction for apparent ileal digestibility (AID) of crude protein (CP) (P < 0.05) indicated lower AID of CP in challenged birds fed high Ca. The challenge decreased AID of Ca (P < 0.01). Ca level had no impact on C. perfringens count, but it decreased Lactobacillus (P < 0.05) and Bifidobacteria (P < 0.05) populations in the ceca. High dietary Ca decreased feed conversion ratio. Overall (42 D), the highest WG was observed in unchallenged birds fed high Ca and high phytase with the lowest WG observed in NE-challenged birds fed low Ca and low phytase. The results suggest that full matrix values for high doses of phytase may be appropriate during NE challenge.

In-feed resin acids reduce matrix metalloproteinase activity in the ileal mucosa of healthy broilers without inducing major effects on the gut microbiota

The chicken gut is constantly exposed to harmful molecules and microorganisms which endanger the integrity of the intestinal wall. Strengthening intestinal mucosal integrity is a key target for feed additives that aim to promote intestinal health in broilers. Recently, dietary inclusion of resin-based products has been shown to increase broiler performance. However, the mode of action is still largely unexplored. Coniferous resin acids are known for their anti-microbial, anti-inflammatory and wound-healing properties, all properties that might support broiler intestinal health. In the current study, the effect of pure resin acids on broiler intestinal health was explored. Ross 308 broilers were fed a diet supplemented with coniferous resin acids for 22 days, after which the effect on both the intestinal microbiota as well as on the intestinal tissue morphology and activity of host collagenases was assessed. Dietary inclusion of resin acids did not alter the morphology of the healthy intestine and only minor effects on the intestinal microbiota were observed. However, resin acids-supplementation reduced both duodenal inflammatory T cell infiltration and small intestinal matrix metalloproteinase (MMP) activity towards collagen type I and type IV. Reduced breakdown of collagen type I and IV might indicate a protective effect of resin acids on intestinal barrier integrity by preservation of the basal membrane and the extracellular matrix. Further studies are needed to explore the protective effects of resin acids on broiler intestinal health under sub-optimal conditions and to elaborate our knowledge on the mechanisms behind the observed effects.

Chemical Composition of Lipophilic Bark Extracts from Pinus pinaster and Pinus pinea Cultivated in Portugal

The chemical composition of lipophilic bark extracts from Pinus pinaster and Pinus pinea cultivated in Portugal was evaluated using gas chromatography-mass spectrometry. Diterpenic resin acids were found to be the main components of these lipophilic extracts, ranging from 0.96 g kg−1 dw in P. pinea bark to 2.35 g kg−1 dw in P. pinaster bark. In particular, dehydroabietic acid (DHAA) is the major constituent of both P. pinea and P. pinaster lipophilic fractions, accounting for 0.45 g kg−1 dw and 0.95 g kg−1 dw, respectively. Interestingly, many oxidized compounds were identified in the studied lipophilic extracts, including DHAA-oxidized derivatives (7-oxo-DHAA, 7α/β-hydroxy-DHAA, and 15-hydroxy-DHAA, among others) and also terpin (an oxidized monoterpene). These compounds are not naturally occurring compounds, and their formation might occur by the exposure of the bark to light and oxygen from the air, and the action of micro-organisms. Some of these compounds have not been previously reported as lipophilic constituents of the bark of the referred pine species. Other constituents, such as aromatic compounds, fatty acids, fatty alcohols, and sterols, are also present in the studied extracts. These results can represent an opportunity to valorize P. pinaster and P. pinea by-products as a primary source of the bioactive resin acids that are integrated into the current uses of these species.