The aim of this study was to investigate the effects of tributyrin supplementation on the production traits, the main metabolic parameters and gut microbiota in weaned piglets. One hundred and twenty crossbred piglets (Large White × Landrace) were randomly divided into two experimental groups (six pens each; 10 piglets per pen): the control group (CTRL), that received a basal diet, and the tributyrin group (TRIB) that received the basal diet supplemented with 0.2% tributyrin. The experimental period lasted 40 days. Production traits were measured at days 14, 28 and 40. A subset composed of 48 animals (n = 4 for each pen; n = 24 per group) was considered for the evaluation of serum metabolic parameters and hair cortisol by enzyme-linked immunosorbent assay (ELISA), and faecal microbiota by real-time polymerase chain reaction (PCR). Our results showed that the treatment significantly increased body weight (BW) at day 28 and day 40 (p = 0.0279 and p = 0.0006, respectively) and average daily gain (ADG) from day 28 to day 40 (p = 0.046). Gain to feed ratio (G:F) was significantly higher throughout the experimental period (p = 0.049). Even if the serum parameters were in the physiological range, albumin, albumin/globulin (A/G) ratio, glucose and high-density lipoproteins (HDL) fraction were significantly higher in the TRIB group. On the contrary, tributyrin significantly decreased the urea blood concentration (p = 0.0026), which was correlated with lean gain and feed efficiency. Moreover, serum insulin concentration, which has a regulatory effect on protein and lipid metabolism, was significantly higher in the TRIB group (p = 0.0187). In conclusion, this study demonstrated that tributyrin can be considered as a valid feed additive for weaned piglets.

We evaluated the effects of leonardite supplementation, mainly composed of humic acids (HAs), as a functional feed additive in weaned piglets. One hundred and twenty piglets (Large Withe × Landrace) were weaned at 28 ± 2 days, and randomly divided into two groups (6 pens per group, 10 piglets per pen). After one week of adaptation, for 40 days groups were fed a control diet (CTRL) and an HA enriched diet (0.25% of leonardite; HAG). Body weight (BW), average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR) were measured throughout the experimental period. On the last day of the trial four piglets per pen were randomly selected and the blood was collected to evaluate the serum metabolic profile and diamine oxidase content.Chemical analyses showed that leonardite was characterized by a high content of ash 23.27% (as-fed basis), polyphenolic content of 35.18 ± 3.91 mg TAEq/g, and an antioxidant capacity of 73.31 ± 8.22 μmol TroloxEq/g.The HAG group showed an increase in BW, ADG and ADFI (P < 0.01) compared to the CTRL group during the experimental period. In terms of the serum metabolic profile, the HAG group showed a significant increase in total protein content (P < 0.001), albumin (P < 0.001), albumin/globulin ratio (P < 0.01), phosphatase alkaline (P < 0.01), calcium, phosphorus and magnesium (P < 0.05) compared to the CTRL group.A modulation in the serum lipid profile was recorded. The HAG group showed a decrease in total triglycerides (P < 0.05) with higher total cholesterol (P < 0.05), however only high-density lipoprotein showed a significant increase (P < 0.001) compared to the CTRL group. No significant differences in the amount of diamine oxidase were found between groups.In conclusion, leonardite inclusion in the diet at 0.25% was shown to have a positive effect on the serum lipid profile and animal growth. This thus suggests that leonardite can be considered as a new feed additive, which improves the health and performance of weaned piglets.

In pig livestock, alternatives to in-feed antibiotics are needed to control enteric infections. Plant extracts such as tannins can represent an alternative as a natural source of functional compounds. The aim of this study was to evaluate the in vitro digestibility and in vivo effects of oral supplementation of combined chestnut (Ch) and quebracho (Qu) tannins in order to establish if they can induce a positive effect on weaned piglets’ performance, metabolic status and fecal parameters. In vitro digestibility (dry matter, DM) of diets was calculated using a multi-step enzymatic technique. In vitro digested diet samples were further tested on an intestinal porcine enterocyte cell line (IPEC-J2). Weaned piglets (n = 120; 28 ± 2 day old) were randomly allotted to two groups (12 pens in total with 10 pigs per pen): control (Ctrl) and treatment (Ch/Qu). After one week of adaptation (day 0), 35-day-old piglets in the Ctrl group were fed a Ctrl diet and the Ch/Qu group were fed with 1.25% Ch/Qu for 40 days. Body weight and feed intake per pen were recorded weekly. At day 40, blood and fecal samples were collected. Principal metabolic parameters were evaluated from blood samples by enzymatic colorimetric analysis. Total phenolic compounds, urea, and ammonia in feces were analyzed (Megazyme International, Bray, Ireland). In vitro digestibility and cell viability assays showed that the inclusion of 1.25% Ch/Qu slightly reduced diet digestibility compared with the Ctrl diet, while intestinal cell viability was not altered with low concentrations of Ch/Qu digesta compared with Ctrl. In vivo results did not show any adverse effects of Ch/Qu on feed intake and growth performance, confirming that dietary inclusion of Ch/Qu at a concentration of 1.25% did not impair animal performance. The decreased diet DM digestibility in the Ch/Qu diet may cause increased serum concentration of albumin (Ctrl: 19.30 ± 0.88; Ch/Qu: 23.05 ± 0.88) and albumin/globulin ratio (Ctrl: 0.58 ± 0.04; Ch/Qu: 0.82 ± 0.04), but decreased creatinine (Ctrl: 78.92 ± 4.18; Ch/Qu: 54.82 ± 4.18) and urea (Ctrl: 2.18 ± 0.19; Ch/Qu: 0.95 ± 0.19) compared with Ctrl. Pigs in the Ch/Qu group contained higher (p < 0.05) concentrations of fecal phenolic compounds and nitrogen than the Ctrl group, while fecal ammonia and urea were not affected by tannins. In conclusion, Ch/Qu tannin supplementation did not influence growth performance. Although lower digestibility was observed in the diet supplemented with Ch/Qu tannins, Ch/Qu supplementation did not show any adverse effect on intestinal epithelial cell viability.

The aim of this study was to evaluate the antioxidant capacity, the antimicrobial proprieties of algae Ascophyllum nodosum and Schizochytrium spp. against one of major swine enteric pathogen Escherichia coli O138 by broth macro-dilution method in Luria-Bertani (LB) medium. The antimicrobial effect of the algal extracts at supplementation of 0.12%, 0.06% and 0.03% (v/v) on E. coli O138, genetically characterised by PCR, was evaluated by following the bacterial growth. The antioxidant activity was determined by the ABTS Radical Cation Decolorisation Assay. In particular, the log 10 E. coli used as control resulted significantly higher than 0.12% at 3 hours (8.82 ± 0.07 and 8.18 ± 0.07 log 10 cells/mL, respectively; p<.01) suggesting an inhibitory activity related to the dose. No effect activity was observed with Schizochytrium spp. against E. coli growth. A. nodosum and Schizochytrium spp. exhibited antioxidant capacity (p<.05). The combination of them (1:1) exhibited antioxidant activity suggesting a synergistic effect (p<.05). The different proprieties of algal species that can modulate the O138 E. coli growth, one of the major pathogen of swine species, together with the antioxidant capacity, make them a promising functional feed additive to improve the gut health, therefore further studies are needed to confirm these activities in vivo. HIGHLIGHTSThe aim of the study was to evaluate the antimicrobial and antioxidant proprieties of two species of algae: Ascophyllum nodosum and Schizochytrium spp. Ascophyllum nodosum revealed antimicrobial effect against Escherichia coli O138. Both algae exhibited antioxidant capacity also with a synergistic effect. ARTICLE HISTORY

Weaned piglets often suffer from the enteric disorders and post-weaning diarrhoea. Natural extracts, due to its functional properties, such as tannins from chestnut and quebracho are often considered as feed additives against diarrhoea after the antibiotics ban (Reg. UE 1831/2003). The aim of this study was to evaluate the dietary effects of tannins on growth performance and blood parameters of weaned piglets. A total of 120 piglets (Large White x Landrace) weaned at d 28±2 were randomly allotted to one of two treatments (control vs. tannin) with 6 pens per treatment and 10 pigs per pen. The tannin diet was supplemented with 1.25% of chestnut and quebracho tannins (Silvateam, Italy). The experiment lasted 40 days. Individual body weight (BW) was recorded at d 0, 14, 28 and 40. Feed intake was measured weekly to calculate feed efficiency from d 0 to 14, d 14 to 28, and d 28 to 40. Blood samples were collected on d 40 from a subset of animals (4 pigs/pen). Data were analyzed using PROC GLIMMIX of SAS 9.4 (SAS Inst. Inc., Cary, NC). Supplementation of tannins did not affect BW and feed intake throughout the experiment. However, addition of tannins showed tendency to increase the feed efficiency on d 14 to d 28, compared with control (P = 0.54; 60.4 vs. 52.3, respectively). Dietary addition of tannins significantly increase the serum concentration of albumin, and decrease of globulin, urea and creatinine compared with control (P &lt; 0.05; 23.05 vs. 19.31 g/L, 30.13 vs. 33.58 g/L; 0.98 vs. 2.18 mmol/L; 53.92 vs. 78.92 μmol/L, respectively). In conclusion, tannin supplementation impacted the blood parameters that were related to protein utilization, although this benefit was not reflected in growth performance of weaned pigs.