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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., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The rumen simulation technique (RUSITEC) was used to investigate the effect of ergot alkaloids (EA) and a mycotoxin deactivating product (Biomin AA; MDP) on nutrient digestion, ruminal fermentation parameters, total gas, methane, and microbial nitrogen production. Ruminal fermentation vessels received a feedlot finishing diet of 90:10 concentrate:barley silage (DM basis). Using a randomized complete block design, treatments were assigned (n = 4 vessels/treatment) within two RUSITEC apparatuses in a 2 × 2 factorial arrangement. Treatments included: (1) control (CON) diet (no EA and no MDP); (2) CON diet + 1 g/d MDP; (3) CON diet + 20 mg/kg EA; and (4) CON diet + 20 mg/kg EA + 1 g/d MDP. The study was conducted over 14 d with 7 d of adaptation and 7 d of sample collection. Data were analyzed in SAS using PROC MIXED including fixed effects of EA, MDP, and the EA×MDP interaction. Random effects included RUSITEC apparatus and cow rumen inoculum (n = 4). Ergot alkaloids decreased dry matter (DMD) (P = 0.01; 87.9 vs. 87.2%) and organic matter disappearance (OMD) (P = 0.02; 88.8 vs. 88.4%). Inclusion of MDP increased OMD (P = 0.01; 88.3 vs. 88.9%). Neutral detergent fiber disappearance (NDFD) was improved with MDP; however, an EA×MDP interaction was observed with MDP increasing (P < 0.001) NDFD more with EA diet compared to CON. Acetate proportion decreased (P = 0.01) and isovalerate increased (P = 0.03) with EA. Consequently, acetate:propionate was reduced (P = 0.03) with EA. Inclusion of MDP increased total volatile fatty acid (VFA) production (P < 0.001), and proportions of acetate (P = 0.03) and propionate (P = 0.03), and decreased valerate (P < 0.001), isovalerate (P = 0.04), and caproate (P = 0.002). Treatments did not affect (P ≥ 0.17) ammonia, total gas, or methane production (mg/d or mg/g of organic matter fermented). The inclusion of MDP reduced (P < 0.001) microbial nitrogen (MN) production in the effluent and increased (P = 0.01) feed particle-bound MN. Consequently, total MN decreased (P = 0.001) with MDP. In all treatments, the dominant microbial phyla were Firmicutes, Bacteroidota, and Proteobacteria, and the major microbial genus was Prevotella. Inclusion of MDP further increased the abundance of Bacteroidota (P = 0.04) as it increased both Prevotella (P = 0.04) and Prevotellaceae&#95;UCG-003 (P = 0.001). In conclusion, EA reduced OMD and acetate production due to impaired rumen function, these responses were successfully reversed by the addition of MDP., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The purpose of this experiment was to determine if supplying butyrate to the postruminal gastrointestinal tract of growing lambs alters blood flow and nutrient flux across the portal-drained viscera (PDV) and hepatic tissues. Polled Dorset wether lambs ( = 10; initial BW = 55 ± 3.3 kg) had catheters surgically implanted into the portal vein, a branch of the hepatic vein, a mesenteric vein, and the abdominal aorta. A cannula was placed in the abomasum to deliver the treatment. Lambs were fed a pelleted ration once daily consisting of 69.7% dehydrated alfalfa, 30.0% ground corn, and 0.3% salt at 1.3 × NE requirement. The experimental design was a crossover balanced in time, so that each lamb received both treatments. Treatments consisted of either a pulse dose infusion of butyrate (buffered solution) to supply butyrate (10 mg/kg BW) or a buffered saline solution (1 mL/kg BW) once daily at the time of feeding. On d 14 of the treatment period, nutrient fluxes were measured using para-aminohippuric acid as a blood flow marker. Blood samples were collected from the aorta, portal vein, and hepatic vein every hour for 9 h beginning at 30 min prior to treatment/feeding. There was a tendency for a treatment × time interaction ( = 0.05) for portal vein blood flow, indicating that blood flow began to decrease earlier postprandial in lambs receiving butyrate. The butyrate treatment tended to increase the uptake of O ( = 0.07) and increased the uptake of glucose ( = 0.002), glutamate ( = 0.04), and glutamine ( = 0.02) by the PDV. There was a treatment × time interaction ( < 0.01) for flux of acetate, propionate, butyrate, isobutyrate, and valerate across the PDV. The interaction was mainly due to an earlier postprandial peak and associated decrease in the flux rate of the VFA. The alteration in timing of the postprandial peak of VFA flux was also observed in hepatic fluxes of VFA. It appears that supplying butyrate to the postruminal tissues through an abomasal cannula increases glucose, glutamate, and glutamine metabolism by the PDV.

A multicatheter sow model was established to study the effects of dietary β-hydroxy β-methyl butyrate (HMB) supplementation on net portal flux (NPF) and net hepatic flux (NHF) of HMB, glucose, and the AA Ala, Gly, Ile, Leu, Phe, Tyr, and Val. Eight second parity sows were fitted with permanent indwelling catheters in an artery and in the portal, hepatic, and mesenteric veins. Eight hourly sets of blood samples were taken starting 30 min before the morning meal on day -3 and day 3 relative to parturition. Four control (CON) sows were fed a standard lactation diet from day -15 and throughout the experiment, and 4 HMB sows were fed the control diet supplemented with 15 mg Ca(HMB)(2)/kg BW mixed in one third of the morning meal from day -10 until parturition. Net portal flux of HMB was affected by treatment (Trt; P < 0.01) and peaked in the HMB sows at 6.9 mmol/h 30 min after the morning meal and then decreased towards preprandial level (0.0 mmol/h) 3.5 h after the meal, revealing that dietary HMB was rapidly absorbed from the intestine. The NHF of HMB tended to be affected by Trt (P = 0.06) showing a small hepatic uptake of HMB (1.1 mmol/h) in HMB sows. Net portal flux of glucose and all measured AA, except for Gly and Tyr, were affected the Trt × time interaction (P < 0.01). The NPF was positive for all nutrients, indicating absorption from the intestine to the portal blood. Absorption rates appeared to be more stable for HMB than for CON sows. Net hepatic flux of glucose was not affected by Trt. It was negative from 1.5 to 2.5 h after the meal, indicating hepatic uptake, but positive before and after, indicating net hepatic release of glucose. Net hepatic fluxes of AA were negative and were not affected by Trt (P > 0.10), except for Phe (P < 0.05). In conclusion, HMB reduced the variation in net portal flux of glucose and AA during 8 h of blood sampling and suggest that the improved sow productivity observed by others may be due to a more uniform nutrient absorption pattern into portal blood.

Supplementation of the leucine metabolite β-hydroxy β-methyl butyrate (HMB) to sows during late gestation or lactation has been shown to improve piglet health, survival, and growth. This study aimed to investigate long-term effects of HMB supplementation to late-gestating sows on body characteristics of piglets at weaning. Sows were fed a standard lactation diet from day -15 relative to parturition and throughout the experiment and a diet supplemented with (HMB; n = 2) or without [control (CON); n = 3] 15 mg Ca(HMB)(2)/kg BW in morning meals from day -10 until parturition. Fifty-six suckling piglets were weighed at day 28 and water content was assessed by deuterium oxide dilution. Piglets were euthanized, organ weights and lengths were recorded, the empty carcass was analyzed for dry matter, ash, and crude protein content, and body fat content was calculated. Two litters were treated for diarrhea, which was included in the statistical model. Weight at birth and at day 28 was not affected by maternal HMB supplementation. The total weight of the small intestine in HMB piglets was 15% lighter (P < 0.01) and the caecum of HMB piglets were 16% longer and 22% heavier (P < 0.01) than in CON piglets, and the large intestine was not affected by treatment. Diarrhea increased the length and weight of small and large intestine (P < 0.01) and weight of the kidneys (P < 0.01). The weight of the liver was increased by 8% in the HMB piglets (P < 0.01) compared with CON piglets, and the spleen was 31% heavier in HMB piglets (P < 0.01). The weight of the kidneys was increased for the HMB piglets (P < 0.01) whereas the weights of stomach and heart were not affected by HMB supplementation. The carcasses of HMB piglets had a lower DM and fat content (P < 0.05) and increased CP content (P < 0.01) compared with CON piglets. In conclusion, the study showed that maternal HMB supplementation in late gestation had long-lasting effects on characteristics of the piglets.

This trial was conducted to investigate whether β-hydroxy β-methyl butyrate (HMB) supplementation during late gestation and throughout lactation would influence colostrum and milk production of sows and neonatal piglet survival (0 to 24 h). Control sows (CON; n = 8) were fed a standard lactation diet from day 108 of gestation and until 28 d after parturition (weaning). Sows fed HMB (n = 8) were fed the CON diet topdressed with 2.5 g Ca(HMB)(2) equally divided at each 2 daily meals throughout the experiment. Litters were standardized to 12 piglets per sow within experimental group on day 1, and both groups weaned on average 11.3 piglets per sow. Blood samples were taken from the sows by jugular vein puncture on days -3, 1, 10, 17, and 28 relative to parturition. Piglets were weighed at birth, after 24 h, and repeatedly throughout lactation to estimate the colostrum and milk yield of the sows. Samples of colostrum and milk were collected and analyzed. Sows fed HMB had a higher colostrum yield (512 vs. 434 ± 30 g/piglet; P = 0.05) estimated based on the piglet weight gain during the colostrum period (132 vs. 76 ± 21 g/piglet; P = 0.05) and the mortality rate of HMB piglets were lower during the colostrum period (0.0 vs. 4.8%, P < 0.05). The HMB supplementation did not affect colostrum composition (P > 0.10). Supplementation with HMB increased milk content of fat (7.40 vs. 6.47 ± 0.30%; P < 0.05), dry matter (19.0 vs. 18.2 ± 0.26; P < 0.05), and energy (4.81 vs. 4.47 ± 0.12 kJ/g; P < 0.05) and reduced the sow backfat at weaning (11.4 vs. 14.5 ± 1.0 mm; P < 0.05). The HMB piglets weighed less at weaning than the control piglets (7.48 vs. 8.30 ± 0.20 kg; P < 0.01), although the milk yield was not reduced. Plasma acetate was higher in HMB sows [202 (175; 233) vs. 158 (141; 179) μM; P < 0.05] whereas plasma 3-hydroxy butyrate was reduced in HMB sows during lactation. In conclusion, HMB supplemented to sows improved the colostrum production but inhibited piglet growth at peak lactation.

The net portal appearance of volatile fatty acids (VFA) was investigated in four ruminally fistulated and multicatheterized sheep. During the experiments, the sheep were fed once every hour for 14 h and intraruminally infused with mixtures of VFA for the 12 h commencing 2 h after the initiation of the hourly feeding protocol. Paired arterial and portal blood samples were obtained hourly during the last 6 h of the experiments. In the control treatment (1), only water was infused intraruminally. In Treatments 2 through 4, the intraruminal infusion rates of propionate (40 mmol/h), isobutyrate (5 mmol/h), and valerate (5 mmol/h) were unchanged. In Treatments 2, 3, and 4, the acetate infusion rate was 100, 60, and 20 mmol/h, respectively, and the butyrate infusion rate was 10, 30, and 50 mmol/h, respectively. Thus, the infusion rate of VFA carbon was constant across Treatments 2 through 4. Portal recovery estimated from the increased net portal appearance in Treatments 2 through 4 compared to the control treatment was 85% for propionate and 60% for isobutyrate, and these recoveries were unaffected by treatment. The portal recovery of butyrate increased (from 21 to 32%) with increasing infusion rate of butyrate and decreasing infusion rate of acetate, as did the portal recovery of valerate (from 14 to 31%). The portal recovery of acetate was 55%, when measured as net portal appearance. Thus, it seems that the capacity for beta-oxidation in ruminal epithelium is limited, which would explain the increasing portal recovery of butyrate and valerate with increasing infusion rate of butyrate, when infusion rate of VFA carbon is unchanged.

Three trials were conducted to test whether feeding the leucine metabolite beta-hydroxy-beta-methyl butyrate (HMB) would increase fat content of sows' milk and pig weight gain. All sows received a basal diet and were assigned at random to receive either 2 g of CaCO3/d (control) or 2 g of Ca(HMB)2/d (HMB), which was top-dressed to the basal diet. Treatment began 3 to 4 d before farrowing. In Trials 1, 2, and 3 there were 4, 19, and 11 pairs of sows, respectively. In a combined analysis that included all three trials, milk fat at d 1 was increased by 41% (P = .01) and pig weight at d 21 was increased by 7% (P = .01) for sows fed diets containing HMB compared with sows fed control diets. Sows fed HMB lost more backfat (P = .03); however, sows receiving HMB had more (P < .05) backfat depth at farrowing than control sows. At weaning there was no difference in backfat depth between the treatment groups. Sows fed HMB tended to consume less feed (P = .07) than control sows. In Trials 2 and 3, data were collected on the subsequent reproductive cycles of the sows. A combined analysis of the data revealed no differences in sow performance when sows previously fed the diet containing HMB were compared with sows previously fed the control diet. In conclusion, beta-hydroxy-beta-methyl butyrate, when fed to sows at 2 g/d, resulted in an increase in fat percentage of sow's milk and pig performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-hydroxy-beta-methyl butyrate (HMB), a compound formed during catabolism of leucine, was fed to 256 crossbred steers as 0 or .03% of diet dry matter. Effects on performance, carcass characteristics, and tissue composition were measured. Groups of 32 steers per diet were slaughtered after 105, 119, 133, and 147 d on feed. The HMB was fed to each group only during the final 82 d they were fed. Averaged across slaughter date, animal performance was not altered by HMB; however, an interaction between HMB and time on feed was detected. Feeding HMB increased (P < .01) daily gain of steers slaughtered at 105 d but decreased (P < .01) daily gain of steers slaughtered at 147 d. Steers fed HMB had numerically higher marbling scores that resulted in a trend toward higher carcass quality grades. Steers receiving HMB tended to have less (P < .08) s.c. fat and fewer steers with yield grades of 4 or greater (1.6 vs 4.7%). Supplementation of HMB to feedlot steers tended to increase (P < .07) the ratio of intramuscular fat to subcutaneous fat. Steers fed HMB had higher (P < .001) blood plasma concentrations of HMB (3.06 vs 1.70 mg/L) and lower (P < .03) blood plasma concentrations of cholesterol (108.4 vs 118.7 mg/dL). Feeding HMB tended to increase (P < .10) lipid content of the longissimus muscles of those steers slaughtered at 105 d.